- published: 14 Nov 2008
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Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around 1,600 kilometres (1,000 mi) from the coast of Africa and 2,250 kilometres (1,400 mi) from the coast of South America, which is roughly midway between the horn of South America and Africa. It is governed as part of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha, of which the main island, Saint Helena, is around 1,300 kilometres (800 mi) to the southeast, and the territory also includes the "remotest populated archipelago" on earth, the sparsely populated Tristan da Cunha archipelago some thirty degrees farther south–about half the way to the Antarctic Circle.
The Island is named after the day of its recorded discovery, Ascension Day, and is located at 7°56′S 14°22′W / 7.933°S 14.367°W / -7.933; -14.367Coordinates: 7°56′S 14°22′W / 7.933°S 14.367°W / -7.933; -14.367, about as far south of the equator as tropical Venezuela is to its north. Historically, it has played a role as an important safe haven and coaling station to mariners and for commercial airliners during the days of international air travel by flying boats and during World War II was an important naval and air station, especially providing antisubmarine warfare bases in the Battle of the Atlantic and throughout the war. Ascension Island was garrisoned by the British Admiralty from 22 October 1815 to 1922.
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Australia
Australia (
/əˈstreɪljə/), officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent as well as the island of Tasmania and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area. Neighbouring countries include Indonesia, East Timor and Papua New Guinea to the north; the Solomon Islands, Vanuatu and New Caledonia to the north-east; and New Zealand to the south-east.
For at least 40,000 years before European settlement in the late 18th century, Australia was inhabited by indigenous Australians, who belonged to one or more of roughly 250 language groups. After discovery by Dutch explorers in 1606, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788. The population grew steadily in subsequent decades; the continent was explored and an additional five self-governing Crown Colonies were established.
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Canada
Canada ( /ˈkænədə/) is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean. Spanning over 9,900,000 km2 (3,800,000 sq mi), Canada is the world's second-largest country by total area, and its common border with the United States is the longest land border in the world.
The land that is now Canada has been inhabited for millennia by various Aboriginal peoples. Beginning in the late 15th century, British and French colonial expeditions explored, and later settled, along the region's Atlantic coast. France ceded nearly all of its colonies in North America in 1763 after the Seven Years' War. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces and territories and a process of increasing autonomy; the Canada Act 1982 severed the vestiges of legal dependence on Britain.
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Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.
It is part of a region known as the Space Coast, and is the site of the Cape Canaveral Air Force Station. Since many U.S. spacecraft are launched from both the station and the Kennedy Space Center on Merritt Island, the terms "Cape Canaveral," "Canaveral", or "the Cape" have become metonyms that refer to both as the launch site of spacecraft. In homage to its spacefaring heritage, the Florida Public Service Commission allocated area code 321 to the Cape Canaveral area.
Other features of the cape include the Cape Canaveral lighthouse and Port Canaveral. The city of Cape Canaveral is a few miles south of the cape. Mosquito Lagoon, the Indian River, Merritt Island National Wildlife Refuge and Canaveral National Seashore are also features of this area.
wn.com/Cape_Canaveral -
China
China (
i/ˈtʃaɪnə/; Chinese: 中国; pinyin: Zhōngguó; see also Names of China), officially the People's Republic of China (PRC), is the world's most-populous country, with a population of over 1.3 billion. Covering approximately 9.6 million square kilometres, the East Asian state is the world's second-largest country by land area, and the third- or fourth-largest in total area, depending on the definition of total area.
The People's Republic of China is a single-party state governed by the Communist Party of China. It exercises jurisdiction over 22 provinces, five autonomous regions, four directly controlled municipalities (Beijing, Tianjin, Shanghai, and Chongqing), and two mostly self-governing special administrative regions (Hong Kong and Macau). Its capital city is Beijing. The PRC also claims Taiwan—which is controlled by the Republic of China (ROC), a separate political entity—as its 23rd province, a claim controversial due to the complex political status of Taiwan and the unresolved Chinese Civil War. The PRC government denies the legitimacy of the ROC.
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Czech Republic
The Czech Republic (i/ˈtʃɛk/ CHEK;Czech: Česká republika, pronounced [ˈtʃɛskaː ˈrɛpuˌblɪka] (
listen), short form Česko Czech pronunciation: [ˈtʃɛskɔ]) is a landlocked country in Central Europe. The country is bordered by Poland to the north, Germany to the west, Austria to the south and Slovakia to the east. Its capital and largest city, with 1.3 million inhabitants, is Prague.
It is a pluralist multi-party parliamentary representative democracy, a member of the European Union, NATO, the OECD, the OSCE, the Council of Europe and the Visegrád Group.
The Czech state, formerly known as Bohemia, was formed in the late 9th century as a small duchy around Prague, at that time under dominance of the powerful Great Moravian Empire (which reached its greatest territorial extent during the reign of Svatopluk I from the House of Mojmír). After the fall of the Empire in 907, the centre of power was transferred from Moravia to Bohemia, under the Přemyslids. During the rule of Přemyslid dukes/kings and their successors, the Luxembourgs, the country reached its greatest territorial extent (13th–14th century). Life in the country was significantly affected by the Hussite wars, during which it faced economic embargo and crusades from all over Europe. Following the Battle of Mohács in 1526, the Crown of Bohemia was gradually integrated into the Habsburg monarchy as one of its three principal parts alongside the Archduchy of Austria and the Kingdom of Hungary. The Bohemian Revolt (1618–20) led to the further centralization of the monarchy including forced recatholization and Germanization. During radical reforms in the 18th century the Bohemian Crown was even de facto abolished (1749). In the 19th century the Czech lands became the industrial powerhouse of the monarchy and the core of the Republic of Czechoslovakia which was formed in 1918, following the collapse of the Austro-Hungarian empire after World War I.
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DCF77
Coordinates: 50°0′56″N 9°00′39″E / 50.01556°N 9.01083°E / 50.01556; 9.01083
DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located at 50°0′56″N 9°00′39″E / 50.01556°N 9.01083°E / 50.01556; 9.01083 in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the Physikalisch-Technische Bundesanstalt, Germany's national physics laboratory. DCF77 has been in service as a standard-frequency station since 1959; date and time information was added in 1973. The timestamp sent is either in UTC+1 or UTC+2 depending on daylight saving time.
The 77.5 kHz carrier signal is generated from local atomic clocks that are linked with the German master clocks in Braunschweig. With a relatively high power of 50 kW, the station can be received in large parts of Europe, as far as 2000 km from Frankfurt (and further away depending on signal propagation and local interference). As an example, reception with high-grade consumer clocks is possible in Portugal and Gibraltar (during night hours). Its signal carries an amplitude-modulated, pulse-width coded 1 bit/s data signal. The same data signal is also phase modulated onto the carrier using a 512-bit long pseudorandom sequence (direct-sequence spread spectrum modulation). The transmitted data repeats each minute.
wn.com/DCF77 -
Diego Garcia
Diego Garcia is a tropical, footprint-shaped coral atoll located south of the equator in the central Indian Ocean at 7 degrees, 26 minutes south latitude. It is part of the British Indian Ocean Territory (BIOT) and is positioned at 72°23' east longitude.
The atoll is approximately 1,800 nautical miles (3,300 km) east of the coast of Africa and 1,200 nautical miles (2,200 km) south of the southern tip of India. Diego Garcia lies at the southernmost tip of the Chagos-Laccadive Ridge a vast submarine range in the Indian Ocean topped by a long chain of coral reefs, atolls, and islands comprising the Lakshadweep, Maldives, and the Chagos Archipelago, in which Diego Garcia is geographically situated. Local time is GMT + 6 hours year-round (no daylight time change).
The US Navy operates a large naval ship and submarine support base, military air base, communications and space tracking facilities, and an anchorage for pre-positioned military supplies for regional operations aboard Military Sealift Command ships in the lagoon.
wn.com/Diego_Garcia -
East Germany
The German Democratic Republic (GDR; German: Deutsche Demokratische Republik [ˈdɔʏtʃə demoˈkʀaːtɪʃə ʀepuˈbliːk] or DDR), informally known as East Germany (German: Ostdeutschland), was a socialist state established by the USSR in 1949 in the Soviet zone of occupied Germany, including East Berlin of the Allied-occupied capital city. The GDR had an area of 107,771 km2 (41,610 mi2), bordering Czechoslovakia to the south, West Germany to the south and west, Poland to the east, and the Baltic Sea to the north. East Germany was dissolved upon joining the institutions of West Germany in the German reunification, on 3 October 1990.
wn.com/East_Germany -
Ecuador
Ecuador (i/ˈɛkwədɔr/ E-kwə-dawr), officially the Republic of Ecuador (Spanish: República del Ecuador [reˈpuβlika ðel ekwaˈðor], which literally translates to the "Republic of the Equator") is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, (along with Chile), that do not have a border with Brazil. The country also includes the Galápagos Islands in the Pacific, about 1,000 kilometres (620 mi) west of the mainland.
The main spoken language in Ecuador is Spanish. Ecuador straddles the equator, from which it takes its name, and has an area of 275,830 km2 (106,500 sq mi). Its capital city is Quito, which was declared a World Heritage Site by UNESCO in the 1970s for having the best preserved and least altered historic center in Latin America. The country's largest city is Guayaquil. The historic center of Cuenca, the third largest city in the country, was also declared a World Heritage Site in 1999, for being an outstanding example of a planned inland Spanish style colonial city in the Americas. Ecuador is also home—despite its size—to a great variety of species, many of them endemic, like those of the Galápagos islands. This species diversity makes Ecuador one of the 17 megadiverse countries in the world. The new constitution of 2008 is the first in the world to recognize legally enforceable Rights of Nature, or ecosystem rights.
wn.com/Ecuador -
France
France (Englishi/ˈfræns/ FRANSS or /ˈfrɑːns/ FRAHNSS; French: [fʁɑ̃s] ( listen)), officially the French Republic (French: République française [ʁepyblik fʁɑ̃sɛz]), is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean. It is often referred to as l’Hexagone ("The Hexagon") because of the geometric shape of its territory. It is the largest western European country and it possesses the second-largest exclusive economic zone in the world, covering 11,035,000 km2 (4,260,000 sq mi), just behind that of the United States (11,351,000 km2 / 4,383,000 sq mi).
Over the past 500 years, France has been a major power with strong cultural, economic, military and political influence in Europe and around the world. During the 17th and 18th centuries, France colonised great parts of North America and Southeast Asia; during the 19th and early 20th centuries, France built the second largest colonial empire of the time, including large portions of North, West and Central Africa, Southeast Asia, and many Caribbean and Pacific Islands.
wn.com/France -
Germany
Germany (i/ˈdʒɜrməni/), officially the Federal Republic of Germany (German: Bundesrepublik Deutschland, pronounced [ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant] ( listen)), is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate. With 81.8 million inhabitants, it is the most populous member state and the largest economy in the European Union. It is one of the major political powers of the European continent and a technological leader in many fields.
A region named Germania, inhabited by several Germanic peoples, was documented before AD 100. During the Migration Period, the Germanic tribes expanded southward, and established successor kingdoms throughout much of Europe. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation while southern and western parts remained dominated by Roman Catholic denominations, with the two factions clashing in the Thirty Years' War, marking the beginning of the Catholic–Protestant divide that has characterized German society ever since. Occupied during the Napoleonic Wars, the rise of Pan-Germanism inside the German Confederation resulted in the unification of most of the German states into the German Empire in 1871 which was Prussian dominated. After the German Revolution of 1918–1919 and the subsequent military surrender in World War I, the Empire was replaced by the Weimar Republic in 1918, and partitioned in the Treaty of Versailles. Amidst the Great Depression, the Third Reich was proclaimed in 1933. The latter period was marked by Fascism and World War II. After 1945, Germany was divided by allied occupation, and evolved into two states, East Germany and West Germany. In 1990 Germany was reunified.
wn.com/Germany -
Hawaii
Coordinates: 21°18′41″N 157°47′47″W / 21.31139°N 157.79639°W / 21.31139; -157.79639
Hawaii (i/həˈwaɪ.iː/ or /həˈwaɪʔiː/; Hawaiian: Hawaiʻi Hawaiian pronunciation: [hɐˈvɐiʔi]) is the most recent of the 50 U.S. states (August 21, 1959), and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean.
Hawaii’s diverse natural scenery, warm tropical climate, abundance of public beaches and oceanic surrounding, and active volcanoes make it a popular destination for tourists, surfers, biologists, and volcanologists alike. Due to its mid-Pacific location, Hawaii has many North American and Asian influences along with its own vibrant native culture. Hawaii has over a million permanent residents along with many visitors and U.S. military personnel. Its capital is Honolulu on the island of Oʻahu.
The state encompasses nearly the entire volcanic Hawaiian Island chain, which comprises hundreds of islands spread over 1,500 miles (2,400 km). At the southeastern end of the archipelago, the eight "main islands" are (from the northwest to southeast) Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Kahoʻolawe, Maui, and the island of Hawaiʻi. The last is by far the largest and is often called "The Big Island" to avoid confusion with the state as a whole. The archipelago is physiographically and ethnologically part of the Polynesian subregion of Oceania.
wn.com/Hawaii -
HLA (radio station)
Coordinates: 36°23′15″N 127°21′59″E / 36.38753°N 127.36650°E / 36.38753; 127.36650 (HLA time signal antenna) HLA is a time signal radio station in Daejeon, South Korea, operated by the Korea Research Institute of Standards and Science. Established on November 24, 1984, it transmits a 2 kW signal on 5 MHz (±0.01 Hz). Originally only transmitted for 7 hours per day (01:00–08:00), 5 days per week (M–F), it is continuous as of 2011, There are over 100 users of the signal in Korea.
It broadcasts a time signal similar to that of the WWV and WWVH stations with which it shares a frequency:
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India
India (i/ˈɪndiə/), officially the Republic of India (Bhārat Gaṇarājya), is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the south-west, and the Bay of Bengal on the south-east, it shares land borders with Pakistan to the west;China, Nepal, and Bhutan to the north-east; and Burma and Bangladesh to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; in addition, India's Andaman and Nicobar Islands share a maritime border with Thailand and Indonesia.
Home to the ancient Indus Valley Civilisation and a region of historic trade routes and vast empires, the Indian subcontinent was identified with its commercial and cultural wealth for much of its long history. Four of the world's major religions—Hinduism, Buddhism, Jainism, and Sikhism—originated here, whereas Zoroastrianism, Christianity, and Islam arrived in the 1st millennium CE and also helped shape the region's diverse culture. Gradually annexed by and brought under the administration of the British East India Company from the early 18th century and administered directly by the United Kingdom from the mid-19th century, India became an independent nation in 1947 after a struggle for independence that was marked by non-violent resistance led by Mahatma Gandhi.
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Japan
Japan
i/dʒəˈpæn/ (Japanese: 日本 Nihon or Nippon; formally 日本国 
Nippon-koku or Nihon-koku, literally the State of Japan) is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south. The characters that make up Japan's name mean "sun-origin", which is why Japan is sometimes referred to as the "Land of the Rising Sun".
Japan is an archipelago of 6,852 islands. The four largest islands are Honshū, Hokkaidō, Kyūshū and Shikoku, together accounting for ninety-seven percent of Japan's land area. Japan has the world's tenth-largest population, with over 127 million people. The Greater Tokyo Area, which includes the de facto capital city of Tokyo and several surrounding prefectures, is the largest metropolitan area in the world, with over 30 million residents.
Archaeological research indicates that people lived in Japan as early as the Upper Paleolithic period. The first written mention of Japan is in Chinese history texts from the 1st century AD. Influence from other nations followed by long periods of isolation has characterized Japan's history. In the late 19th and early 20th centuries, victory in the First Sino-Japanese War, the Russo-Japanese War and World War I allowed Japan to expand its empire during a period of increasing militarism. The Second Sino-Japanese War of 1937 expanded into part of World War II in 1941, which came to an end in 1945 following the atomic bombings of Hiroshima and Nagasaki. Since adopting its revised constitution in 1947, Japan has maintained a unitary constitutional monarchy with an emperor and an elected parliament called the Diet.
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Moneron Island
Moneron Island, (Russian: Монерон, Japanese: 海馬島 Kaibato, Ainu: Totomoshiri) is a Russian possession located off Sakhalin Island.
Moneron has an area of about 30 square kilometres (12 sq mi) and a highest point of 429 metres (1,407 ft). It is approximately 4.5 miles (7.2 km) long (N/S axis) by 3.5 miles (5.6 km) wide, and is located 41 nautical miles (76 km) from Sakhalin's port of Nevelsk and about 24 nautical miles (44 km) directly southwest of Sakhalin Island itself at the northeastern end of the Sea of Japan. It has no permanent population.
The island was known as Totomoshiri ("island of sea lions") by its original Ainu inhabitants. It came under the daimyo of Matsumae clan in the 18th century and got its current European name from a visit of the French navigator La Perouse, who named it Moneron after Paul Mérault Monneron, the chief engineer of his expedition. Latterly, the Japanese named it Kaibatō (海馬島), which was a Sinicized rendition of its Ainu name, but it reverted to its European name after Japan's defeat in World War II and its occupation by the Soviet Union.
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QUALCOMM
Qualcomm (NASDAQ: QCOM) is an American global telecommunications equipment corporation that designs, manufactures and markets digital wireless telecommunications products and services based on its code division multiple access (CDMA) technology and other technologies. Headquartered in San Diego, CA, USA. The company operates through four segments: Qualcomm CDMA Technologies (QCT); Qualcomm Technology Licensing (QTL); Qualcomm Wireless & Internet (QWI), and Qualcomm Strategic Initiatives (QSI).
Qualcomm was founded in 1985 by MIT Alumnus and UC San Diego Professor Irwin Jacobs, MIT and USC Alumnus Andrew Viterbi, Harvey White, Adelia Coffman, Andrew Cohen, Klein Gilhousen, and Franklin Antonio. Jacobs and Viterbi had previously founded Linkabit. Qualcomm's first products and services included the OmniTRACS satellite locating and messaging service, used by long-haul trucking companies, developed from a product called Omninet owned by Parviz Nazarian and Neil Kadisha, and specialized integrated circuits for digital radio communications such as a Viterbi decoder.
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Russia
Russiai/ˈrʌʃə/ or /ˈrʊʃə/ (Russian: Россия, tr. Rossiya; IPA: [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation (Russian: Российская Федерация, tr. Rossiyskaya Federatsiya; IPA: [rɐˈsʲijskəjə fʲɪdʲɪˈratsɨjə] ( listen)), is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects. From northwest to southeast, Russia shares borders with Norway, Finland, Estonia, Latvia, Lithuania and Poland (both via Kaliningrad Oblast), Belarus, Ukraine, Georgia, Azerbaijan, Kazakhstan, China, Mongolia, and North Korea. It also has maritime borders with Japan by the Sea of Okhotsk, and the US state of Alaska by the Bering Strait. At 17,075,400 square kilometres (6,592,800 sq mi), Russia is the largest country in the world, covering more than one eighth of the Earth's inhabited land area. Russia is also the eighth most populous nation with 143 million people. It extends across the whole of northern Asia and 40% of Europe, spanning nine time zones and incorporating a wide range of environments and landforms. Russia has the world's largest reserves of mineral and energy resources and is the largest producer of oil and natural gas globally. Russia has the world's largest forest reserves and its lakes contain approximately one-quarter of the world's fresh water.
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RWM
Coordinates: 55°43′36.73″N 38°12′29.39″E / 55.7268694°N 38.2081639°E / 55.7268694; 38.2081639 RWM is the callsign of a high frequency (shortwave) standard frequency and time signal radio station in Moscow, Russia. RWM transmits on 4996 kHz with 5 kW and on 9996 and 14996 kHz with 8 kW.
The frequencies are very close to those of WWV, and WWVH. Because of this, RWM is very difficult to receive in North America with simple receivers of low selectivity, due to interference from these said stations.
The mode of transmission is N0N and A1A (CW). Between 0 and 8 minutes past the hour, RWM transmits a straight unmodulated carrier wave. At 9 minutes past, RWM identifies itself in Morse code. Between 10 and 20 minutes past the hour, RWM transmits a pulse of carrier every second, with the difference between UT1 and UTC in units of one-fiftieth of a second encoded onto the once-per-second pulses. Between 20 and 30 minutes past the hour, RWM transmits 10 carrier pulses each second. This transmission cycle is repeated every half hour.
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Sakhalin
Sakhalin (Russian: Сахалин, pronounced [səxɐˈlʲin]; also known as Kuye (simplified Chinese: 库页; traditional Chinese: 庫頁; pinyin: Kùyè); Japanese: Karafuto (樺太?) or Saharin (サハリン?)) or Saghalien, is a large island in the North Pacific, lying between 45°50' and 54°24' N.
It is part of Russia, and is Russia's largest island, and is administered as part of Sakhalin Oblast. Sakhalin, which is about one fifth the size of Japan, is just off the east coast of Russia, and just north of Japan.
The indigenous peoples of the island are the Ainu, Oroks, and Nivkhs. Most Ainu relocated to Hokkaidō when the Japanese were displaced from the island in 1949.
Sakhalin was claimed by both Russia and Japan in the course of the 19th and 20th centuries, which led to bitter disputes between the two countries over control of the island.
The European names derive from misinterpretation of a Manchu name sahaliyan ula angga hada ("peak/craggy rock at the mouth of the Amur River"). Sahaliyan, the word that has been borrowed in the form of "Sakhalin", means "black" in Manchu and is the proper Manchu name of the Amur River (sahaliyan ula, literally "Black River" ; see Sikhote-Alin). Its Japanese name, Karafuto (樺太?), supposedly comes from Ainu kamuy kar put ya mosir (カムイ・カラ・プト・ヤ・モシリ, shortened to Karput カラ・プト), which means "Land/Island/Country at the Shore of the God-Made (River) Mouth/Confluence."[citation needed] The name was used by the Japanese during their possession of its southern part (1905–1945).
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South Korea
South Korea ( listen), officially the Republic of Korea (Hangul: 대한민국; Hanja: 大韓民國; Daehan Minguk listen), is a sovereign state in the southern part of the Korean Peninsula. The name "Korea" is derived from Goryeo, a dynasty which ruled in the Middle Ages (an initial "G" in Korean is pronounced like an English "K").
Its neighbors are China to the west, Japan to the east, North Korea to the north, and the Korea Strait to the south. South Korea lies in the north temperate zone with a predominantly mountainous terrain. It covers a total area of 99,392 square kilometers and has a population of almost 50 million. The capital and largest city is Seoul, with a population of 9,794,304.
Archaeological findings show that the Korean Peninsula was occupied by the Lower Paleolithic period.Korean history begins with the founding of Gojoseon in 2333 BC by the legendary Dan-gun. Following the unification of the Three Kingdoms of Korea under Silla 668 AD, Korea went through the Goryeo Dynasty and Joseon Dynasty as one nation until the end of the Korean Empire in 1910, when it was annexed by Japan. After liberation and occupation by Soviet and U.S. forces at the end of World War II, the nation was divided into North and South Korea. The latter was established in 1948 as a democracy, though political turmoil and times of military rule and martial law characterized much of the period until the foundation of the Sixth Republic in 1987.
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Soviet Union
The Soviet Union (Russian: Советский Союз, tr. Sovetsky Soyuz), officially the Union of Soviet Socialist Republics (USSR; Russian: Сою́з Сове́тских Социалисти́ческих Респу́блик, tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik; IPA: [sɐˈjus sɐˈvʲetskʲɪx sətsɨəlʲɪˈstʲitɕɪskʲɪx rʲɪsˈpublʲɪk] ( listen); abbreviated СССР, SSSR), was a constitutionally socialist state that existed in Eurasia between 1922 and 1991.
The Soviet Union was a single-party state ruled by the Communist Party from its foundation until 1990. A union of 15 subnational Soviet republics, the Soviet state was structured under a highly centralized government and economy.
The Russian Revolution of 1917 caused the downfall of the Russian Empire. Following the Russian Revolution, there was a struggle for power between the Bolshevik party, led by Vladimir Lenin, and the anti-communist White movement. In December 1922, the Bolsheviks won the civil war, and the Soviet Union was formed with the merger of the Russian Soviet Federative Socialist Republic, the Transcaucasian Socialist Federative Soviet Republic, the Ukrainian Soviet Socialist Republic and the Byelorussian Soviet Socialist Republic.
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Stanford University
Coordinates: 37°26′N 122°10′W / 37.43°N 122.17°W / 37.43; -122.17
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto, California, United States. It is situated in the northwestern Silicon Valley, approximately 20 miles (32 km) northwest of San Jose and 37 miles (60 km) southeast of San Francisco.
Leland Stanford, a Californian railroad tycoon and politician, and his wife Jane Lathrop Stanford founded the university in 1891 in honor of their son, Leland Stanford, Jr., who died of typhoid two months before his 16th birthday. The university was established as a coeducational and nondenominational institution, but struggled financially after the senior Stanford's 1893 death and after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, Provost Frederick Terman supported faculty and graduates' entrepreneurialism to build self-sufficient local industry in what would become known as Silicon Valley. By 1970, Stanford was home to a linear accelerator, was one of the original four ARPANET nodes, and had transformed itself into a major research university in computer science, mathematics, natural sciences, and social sciences.
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Switzerland
Switzerland (German: die Schweiz[ˈʃvaɪts]; French: Suisse [sɥis(ə)]; Italian: Svizzera [ˈzvit͡sːɛra]; Romansh: Svizra [ˈʒviːtsrɐ] or [ˈʒviːtsʁːɐ]), in its full name the Swiss Confederation (Latin: Confoederatio Helvetica, hence its abbreviation CH), is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in western Europe, where it is bordered by Germany to the north, France to the west, Italy to the south, and Austria and Liechtenstein to the east.
Switzerland is a landlocked country geographically divided between the Alps, the Swiss Plateau and the Jura, spanning an area of 41,285 km2 (15,940 sq mi). While the Alps occupy the greater part of the territory, the Swiss population of approximately 8 million people is concentrated mostly on the Plateau, where the largest cities are to be found. Among them are the two global cities and economic centres of Zurich and Geneva.
The Swiss Confederation has a long history of armed neutrality—it has not been in a state of war internationally since 1815—and did not join the United Nations until 2002. It pursues, however, an active foreign policy and is frequently involved in peace-building processes around the world. Switzerland is also the birthplace of the Red Cross and home to a large number of international organizations, including the second largest UN office. On the European level, it is a founding member of the European Free Trade Association and is part of the Schengen Area – although it is notably not a member of the European Union, nor the European Economic Area.
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United Kingdom
The United Kingdom of Great Britain and Northern Ireland (commonly known as the United Kingdom, the UK, or Britain) is a sovereign state located off the north-western coast of continental Europe. The country includes the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another sovereign state—the Republic of Ireland. Apart from this land border the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel and the Irish Sea.
The United Kingdom is a unitary state governed under a constitutional monarchy and a parliamentary system, with its seat of government in the capital city of London. It is a country in its own right and consists of four countries: England, Northern Ireland, Scotland and Wales. There are three devolved administrations, each with varying powers, based in Belfast, Edinburgh and Cardiff, the capitals of Northern Ireland, Scotland, and Wales. Associated with the UK, but not constitutionally part of it, are three Crown Dependencies. The United Kingdom has fourteen overseas territories. These are remnants of the British Empire which, at its height in 1922, encompassed almost a quarter of the world's land surface and was the largest empire in history. British influence can still be observed in the language, culture and legal systems of many of its former territories.
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United States
The United States of America (commonly abbreviated to the United States, the U.S., the USA, America, and the States) is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to the east and Russia to the west, across the Bering Strait. The state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories in the Pacific and Caribbean.
At 3.79 million square miles (9.83 million km2) and with over 312 million people, the United States is the third or fourth largest country by total area, and the third largest by both land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The U.S. economy is the world's largest national economy, with an estimated 2011 GDP of $15.1 trillion (22% of nominal global GDP and over 19% of global GDP at purchasing-power parity). Per capita income is the world's sixth-highest.
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USNO
The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation, and Timing (PNT) for the U.S. Navy and the U.S. Department of Defense. Located in Northwest Washington, D.C., it is one of the pre-1900 astronomical observatories located in an urban area; at the time of its construction, it was far from the light pollution thrown off by the (then-smaller) city center. Today, the observatory's primary observational work is done at the U.S. Navy's higher elevation United States Naval Observatory, Flagstaff Station (NOFS) near Flagstaff, Arizona. USNO also has an "Alternate Master Clock" site in Colorado Springs, CO which, with the "Master Clock", provides precise time to the GPS satellite constellation run by the U.S. Air Force; and it performs radio VLBI-based positions of quasars with numerous global collaborators, in order to produce Earth Orientation parameters. Aside from its scientific mission, since 1974, the Observatory is the official residence of the Vice President of the United States.
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Venezuela
Venezuela (i/ˌvɛnɨˈzweɪlə/ VEN-ə-ZWAY-lə), officially called the Bolivarian Republic of Venezuela (Spanish: República Bolivariana de Venezuela [repuˈβlika βoliβaˈɾjana ðe βeneˈswela]), is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south. Its northern coastline of roughly 2,800 kilometres (1,700 mi) includes numerous islands in the Caribbean Sea, and in the north east borders the northern Atlantic Ocean. Caribbean islands such as Trinidad and Tobago, Grenada, Curaçao, Bonaire, Aruba and the Leeward Antilles lie near the Venezuelan coast. Venezuela's territory covers around 916,445 square kilometres (353,841 sq mi) with an estimated population of 29,105,632. Venezuela is considered a state with extremely high biodiversity, with habitats ranging from the Andes mountains in the west to the Amazon Basin rainforest in the south, via extensive llanos plains and Caribbean coast in the center and the Orinoco River Delta in the east.
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Virginia
Virginia (i/vərˈdʒɪnjə/), officially the Commonwealth of Virginia, is a U.S. state located in the South Atlantic region of the United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most populous city and Fairfax County the most populous political subdivision. The Commonwealth's population is over eight million.
The area's history begins with several indigenous groups, including the Powhatan. In 1607 the London Company established the Colony of Virginia as the first permanent New World English colony. Slave labor and the land acquired from displaced Native American tribes each played a significant role in the colony's early politics and plantation economy. Virginia was one of the 13 Colonies in the American Revolution and joined the Confederacy in the American Civil War, during which Richmond was made the Confederate capital and Virginia's northwestern counties separated to form the state of West Virginia. Although the Commonwealth was under conservative single-party rule for nearly a century following Reconstruction, both major national parties are competitive in modern Virginia.
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WWVB
WWVB is a NIST time signal radio station near Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks in most of North America use to synchronize themselves. The signal transmitted from WWVB is a continuous 60 kHz carrier wave, derived from a set of atomic clocks located at the transmitter site. A one-bit-per-second time code, which is based on the IRIG "H" format of time code and derived from the same set of atomic clocks, is then modulated onto the carrier wave using a technique described as pulse width modulation followed by amplitude-shift keying. A single complete frame of time code begins on the second, lasts one minute, and conveys the year, day of year, hour, minute, and other information as of the beginning of the frame.
While most time signals encode the local time of the broadcasting nation, the United States spans multiple time zones, so WWVB broadcasts the time in Coordinated Universal Time (UTC). Radio-controlled clocks have to convert this to their own local time for display.
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Al Gore
Albert Arnold "Al" Gore, Jr. (born March 31, 1948) served as the 45th Vice President of the United States (1993–2001), under President Bill Clinton. He was the Democratic Party's nominee for President and won the popular vote in the 2000 U.S. presidential election.
Gore is currently an author and environmental activist. He has founded a number of non-profit organizations, including the Alliance for Climate Protection, and has received a Nobel Peace Prize for his work in climate change activism.
Gore was previously an elected official for 24 years, representing Tennessee in the U.S. House of Representatives (1977–85), and later in the U.S. Senate (1985–93), and finally becoming Vice President in 1993. In the 2000 presidential election, Gore won the popular vote by a margin of more than 500,000 votes. However, he ultimately lost the Electoral College to Republican George W. Bush when the U.S. Supreme Court settled the legal controversy over the Florida vote recount by ruling 5-4 in favor of Bush. It was the only time in history that the Supreme Court has determined the outcome of a presidential election.
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Anatol Rapoport
Anatol Rapoport (Russian: Анато́лий Бори́сович Рапопо́рт, born May 22, 1911 – January 20, 2007) was a Russian-born American Jewish mathematical psychologist. He contributed to general systems theory, mathematical biology and to the mathematical modeling of social interaction and stochastic models of contagion.
Rapoport was born in Lozоvaya, Kharkov Governorate, Russia (in today's Kharkiv Oblast, Ukraine). In 1922, he came to the United States, and in 1928 he became a naturalized citizen. He started studying music in Chicago and continued with piano, conducting and composition at the Vienna Hochschule für Musik where he studied from 1929 to 1934. However, due to the rise of Nazism, he found it impossible to make a career as a pianist.
He shifted his career into mathematics, getting a Ph.D. degree in mathematics under Otto Schilling and Abraham Adrian Albert at the University of Chicago in 1941 on the thesis Construction of Non-Abelian Fields with Prescribed Arithmetic. According to the Toronto Globe and Mail, he was a member of the American Communist Party for three years, but quit before enlisting in the U.S. Army Air Corps in 1941, serving in Alaska and India during World War II.
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Anthony Wilden
Anthony Wilden (14 December 1935, London, England) is a writer, social theorist, college lecturer, and consultant. Wilden has published numerous books and articles which intersect a number of fields, including systems theory, film theory, structuralism, cybernetics, psychiatry, anthropological theory, water control projects, urban ecosystems, resource conservation, and communications and social relations.
Wilden is credited with one of the first significant introductions to the work of Jacques Lacan in the Anglo-Saxon world, particularly in his role as one of Lacan's early English translators. Today and into the 21st century Wilden's work (and consequent reputation) is arguably more influential in the fields of communication theory, ecology and social interaction. These fields of study evolved out of a long scholarly tradition of "interactional semiotics" that originated with Plato's Cratylus. Along with such figures as Gregory Bateson (ie., Steps to an Ecology of Mind), R. D. Laing (ie., Sanity, Madness and the Family), and Walker Percy (ie., Lost in the Cosmos), Wilden is considered one of this tradition's contemporary (modern and postmodern) pioneers.
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Bill Clinton
William Jefferson "Bill" Clinton (born William Jefferson Blythe III; August 19, 1946) is an American politician who served as the 42nd President of the United States from 1993 to 2001. Inaugurated at age 46, he was the third-youngest president. He took office at the end of the Cold War, and was the first president of the baby boomer generation. Clinton has been described as a New Democrat. Many of his policies have been attributed to a centrist Third Way philosophy of governance.
Born and raised in Arkansas, Clinton became both a student leader and a skilled musician. He is an alumnus of Georgetown University where he was Phi Beta Kappa and earned a Rhodes Scholarship to attend the University of Oxford. He is married to Hillary Rodham Clinton, who has served as the United States Secretary of State since 2009 and was a Senator from New York from 2001 to 2009. Both Clintons received law degrees from Yale Law School, where they met and began dating. As Governor of Arkansas, Clinton overhauled the state's education system, and served as Chair of the National Governors Association.
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Bradford Parkinson
Bradford Parkinson (February 16, 1935) is an American engineer and inventor, and United States Air Force colonel best known as the father of the Global Positioning System.
He attended the United States Naval Academy, graduating in 1957, but decided to join the Air Force because of its superior educational opportunities. Parkinson then attended the Massachusetts Institute of Technology for his M.S. in Aeronautics, graduating in 1961.
After several years in the Air Force, he entered a Ph. D. program at Stanford University, graduating in 1966. In 1973 he became manager of the NAVSTAR GPS development program, where he remained until 1978 when he retired from the Air Force. In 1984, Parkinson became a professor at Stanford University, where today he is a professor emeritus.
In 2003 he shared the Draper Prize with Ivan A. Getting for his contributions to the invention of the Global Positioning System. In 2004 he was inducted into the National Inventors Hall of Fame. Today Parkinson lives in San Luis Obispo, California near his six children and five grandchildren.
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Béla H. Bánáthy
Béla Heinrich Bánáthy (December 1, 1919 – September 4, 2003) was a Hungarian linguist, systems scientist and a professor at San Jose State University and UC Berkeley. Bánáthy was the founder of the White Stag Leadership Development Program whose leadership model was adopted across the United States. He is also founder of the International Systems Institute with its innovative "conversation"-oriented conference structure, co-founder of the General Evolutionary Research Group, an influential professor of systems theory and a widely-read and respected author.
Béla Bánáthy was born in 1919 in Gyula, Hungary. The oldest of four sons, his father Peter was a minister of the Reformed Church in Hungary and his mother Hildegard Pallmann was a teacher. Peter Bánáthy had earned the honorary title Vitéz for his service during World War I, and Béla, as his oldest son, would inherit the title.
When Bánáthy was about six years old, their family informally adopted Tamas Feri. Tamas was about 13 years old and from a poor gardener family. Tamas took Bánáthy on his first overnight camp out with his patrol to a small forest near Gyula. Bánáthy's father then became the Scoutmaster of the "small scouts" troop (similar to American Cub Scouts).
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C. West Churchman
Charles West Churchman (29 August 1913, Philadelphia – 21 March 2004 Bolinas, California) was an American philosopher and systems scientist, who was Professor at the School of Business Administration and Professor of Peace and Conflict Studies at the University of California, Berkeley. He was internationally known for his pioneering work in operations research, system analysis and ethics.
Churchman was born in Philadelphia in 1913, Pennsylvania, to Clark Wharton Churchman and Helen Norah Fassitt, descendents of old line Philadelphia families. His first intellectual love was for philosophy and this far-ranging love for wisdom captivated him to the end of his life. He studied philosophy at the University of Pennsylvania, where he was admitted to the Zeta Psi fraternity. He earned a bachelor's degree in 1935, a master's in 1936, and a PhD in 1938, all in philosophy. One of his teachers was Edgar A. Singer, who had been a student at Harvard of the philosopher and psychologist William James.
Before completing his dissertation, in 1937, he became Instructor of Philosophy, also at the University of Pennsylvania. Upon finishing his degree, he was appointed Assistant Professor at the University. During World War II, Churchman headed the mathematical section of the U.S. Ordnance Laboratory at the Frankford Arsenal in Philadelphia and devised a way to test small arms ammunition and detonators based on the statistical methods of bioassay. He also investigated the theory of detonation, applying high-speed photography. In 1945, back in Pennsylvania he was elected Chairman of the Department of Philosophy. In 1951, Churchman moved to the Case Institute of Technology in Cleveland, Ohio, and until 1957 he was Professor of Engineering Administration at Case. In 1957, he joined the faculty of the University of California, Berkeley and remained there as a Professor Emeritus after his retirement.
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Charles A S Hall
Charles A.S. Hall is ESF Foundation Distinguished Professor at State University of New York in the College of Environmental Science & Forestry. Hall describes himself primarily as a systems ecologist in the field of Systems ecology with strong interests in biophysical economics, and the relation of energy to society.
Dr. Hall was trained as a systems ecologist by Howard Odum at the University of North Carolina. Since then he has had a diverse career at Brookhaven Laboratory, The Ecosystems Center at the Marine Biological Laboratory, Woods Hole, Cornell University, University of Montana and, for the last 20 years, at the State University of New York College of Environmental Science and Forestry (SUNY ESF). His work has involved streams, estuaries and tropical forests but focused increasingly on human-dominated ecosystems in the US and Latin America. His research reflects his interest in understanding and developing analyses and computer simulation models of the complex systems of nature and humans and their interactions. Halls focus has been on energy as it relates to economics and environment. His focus is studying material and energy flows referred to as Industrial ecology, and applying this perspective, to attempting to understand human economies from a biophysical rather than just social perspective. Dr. Hall teaches a freshman course called The Global Environment and the Evolution of Human Culture and graduate level courses in Systems Ecology, Ecosystems, Energy systems, Tropical Development and Biophysical Economics.
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China
China (i/ˈtʃaɪnə/; Chinese: 中国; pinyin: Zhōngguó; see also Names of China), officially the People's Republic of China (PRC), is the world's most-populous country, with a population of over 1.3 billion. Covering approximately 9.6 million square kilometres, the East Asian state is the world's second-largest country by land area, and the third- or fourth-largest in total area, depending on the definition of total area.
The People's Republic of China is a single-party state governed by the Communist Party of China. It exercises jurisdiction over 22 provinces, five autonomous regions, four directly controlled municipalities (Beijing, Tianjin, Shanghai, and Chongqing), and two mostly self-governing special administrative regions (Hong Kong and Macau). Its capital city is Beijing. The PRC also claims Taiwan—which is controlled by the Republic of China (ROC), a separate political entity—as its 23rd province, a claim controversial due to the complex political status of Taiwan and the unresolved Chinese Civil War. The PRC government denies the legitimacy of the ROC.
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Claude Shannon
Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electronic engineer, and cryptographer known as "the father of information theory".
Shannon is famous for having founded information theory with one landmark paper published in 1948. But he is also credited with founding both digital computer and digital circuit design theory in 1937, when, as a 21-year-old master's student at MIT, he wrote a thesis demonstrating that electrical application of Boolean algebra could construct and resolve any logical, numerical relationship. It has been claimed that this was the most important master's thesis of all time. Shannon contributed to the field of cryptanalysis during World War II and afterwards, including basic work on code breaking.
Shannon was born in Petoskey, Michigan. His father, Claude Sr (1862–1934), a descendant of early New Jersey settlers, was a self-made businessman and for a while, Judge of Probate. His mother, Mabel Wolf Shannon (1890–1945), daughter of German immigrants, was a language teacher and for a number of years principal of Gaylord High School, Michigan. The first 16 years of Shannon's life were spent in Gaylord, Michigan, where he attended public school, graduating from Gaylord High School in 1932. Shannon showed an inclination towards mechanical things. His best subjects were science and mathematics, and at home he constructed such devices as models of planes, a radio-controlled model boat and a wireless telegraph system to a friend's house half a mile away. While growing up, he worked as a messenger for Western Union. His childhood hero was Thomas Edison, who he later learned was a distant cousin. Both were descendants of John Ogden, a colonial leader and an ancestor of many distinguished people.
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Donella Meadows
Donella H. "Dana" Meadows (March 13, 1941 Elgin, Illinois, USA - February 20, 2001, Hanover, New Hampshire) was a pioneering American environmental scientist, teacher and writer. She is best known as lead author of the influential book The Limits to Growth, which made headlines around the world.
Born in Elgin, Illinois, Meadows was educated in science, receiving a B.A. in chemistry from Carleton College in 1963, and a Ph.D. in biophysics from Harvard in 1968. After a year-long trip with her husband, Dennis Meadows, from England to Sri Lanka and back, she became, along with him, a research fellow at MIT as a member of a team in the department created by Jay Forrester, the inventor of system dynamics as well as the principle of magnetic data storage for computers. She taught at Dartmouth College for 29 years, beginning in 1972.
Meadows was honored both as a Pew Scholar in Conservation and Environment (1991) and as a MacArthur Fellow (1994). She received the Walter C. Paine Science Education Award in 1990. She also posthumously received the John H. Chafee Excellence in Environmental Affairs Award for 2001 presented by the Conservation Law Foundation.
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Edward Norton Lorenz
Edward Norton Lorenz (May 23, 1917 – April 16, 2008) was an American mathematician and meteorologist, and a pioneer of chaos theory. He discovered the strange attractor notion and coined the term butterfly effect.
Lorenz was born in West Hartford, Connecticut. He studied mathematics at both Dartmouth College in New Hampshire and Harvard University in Cambridge, Massachusetts. From 1942 until 1946, he served as a meteorologist for the United States Army Air Corps. After his return from the war, he decided to study meteorology. Lorenz earned two degrees in the area from the Massachusetts Institute of Technology where he later was a professor for many years. He was a Professor Emeritus at MIT from 1969 until his death.
During the 1950s, Lorenz became skeptical of the appropriateness of the linear statistical models in meteorology, as most atmospheric phenomena involved in weather forecasting are non-linear. His work on the topic culminated in the publication of his 1963 paper Deterministic Nonperiodic Flow in Journal of the Atmospheric Sciences, and with it, the foundation of chaos theory. His description of the butterfly effect followed in 1969,. He was awarded the Kyoto Prize for basic sciences, in the field of earth and planetary sciences, in 1991, the Buys Ballot Award in 2004, and the Tomassoni Award in 2008.[citation needed] In his later years, he lived in Cambridge, Massachusetts. He was an avid outdoorsman, who enjoyed hiking, climbing, and cross-country skiing. He kept up with these pursuits until very late in his life, and managed to continue most of his regular activities until only a few weeks before his death. According to his daughter, Cheryl Lorenz, Lorenz had "finished a paper a week ago with a colleague." On April 16, 2008, Lorenz died at his home in Cambridge at the age of 90, having suffered from cancer.
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Francis X. Kane
Colonel Francis X. "Duke" Kane, Ph.D., USAF, retired, (born December 12, 1918) is the space planner and engineer responsible for the design concept of the Global Positioning System (GPS). Colonel Kane was General Bernard A. Schriever's Chief for Space and Ballistic Missile Planning at the U.S. Air Force Systems Command from 1961-1970. Colonel Kane was responsible for space systems planning in Project Forecast (1963–1964). Project Forecast was the longest range technology forecast undertaken by the U.S. military prior to 1963. Project forecast contemplated the strategic technological environment of 1975 and the requirements for U.S. advancements in air, space, missile and computer technology.
In 1963, the Air Force Space Systems Division funded Colonel Kane to lead a classified project known as 621B. Phase I of 621B was for the engineering concept for a "space-based navigation system" that would later become known as the Global Positioning System (GPS). According to Colonel Brad Parkinson (USAF, retired), Project 621B had "many of the attributes that you now see in GPS. It has probably never been given its due credit."
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Francisco Varela
Francisco Javier Varela García (September 7, 1946 – May 28, 2001), was a Chilean biologist, philosopher and neuroscientist who, together with his teacher Humberto Maturana, is best known for introducing the concept of autopoiesis to biology, and for co-founding the Mind and Life Institute to promote dialog between science and Buddhism.
Francisco Varela was born in 1946 in Santiago in Chile. After completing secondary school at the Liceo Aleman de Santiago (1951–1963). Like his mentor Humberto Maturana, Varela first studied medicine then biology at the University of Chile, then did a Ph.D. in biology at Harvard University. His thesis, defended in 1970 and supervised by Torsten Wiesel, was titled Insect Retinas: Information processing in the compound eye.
After the 1973 military coup led by Augusto Pinochet, Varela and his family spent 7 years in exile in the USA before returning to Chile to become a Professor of biology.
Varela became a Tibetan Buddhist in the 1970s, initially studying, together with Keun-Tshen Goba, with the meditation master Chögyam Trungpa Rinpoche, founder of Vajradhatu and Shambhala Training, and later with Tulku Urgyen Rinpoche, a Nepalese meditation master of higher tantras.
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George Dantzig
George Bernard Dantzig (November 8, 1914 – May 13, 2005) was an American mathematical scientist who made important contributions to operations research, computer science, economics, and statistics.
Dantzig is known for his development of the simplex algorithm, an algorithm for solving linear programming problems, and his work with linear programming, some years after it was invented by the Soviet mathematician & economist Leonid Kantorovich[citation needed]. In statistics, Dantzig solved two open problems in statistical theory, which he had mistaken for homework after arriving late to a lecture of Jerzy Neyman.
Dantzig was the Professor Emeritus of Transportation Sciences and Professor of Operations Research and of Computer Science at Stanford.
Born in Portland, Oregon, George Bernard Dantzig was named after George Bernard Shaw, the Irish writer.. His father, Tobias Dantzig, was a Baltic German mathematician and linguist, and his mother, Anja Dantzig (née Ourisson), was a French linguist. Dantzig's parents met during their study at the Sorbonne University in Paris, where Tobias studied mathematics under Henri Poincaré. The Dantzigs immigrated to the United States, where they settled in Portland, Oregon.
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George Klir
George Jiri Klir (born 1932 Prague, Czechoslovakia) is a Czech-American computer scientist and professor of systems sciences at the Center for Intelligent Systems at Binghamton University in Binghamton, New York.
George Klir was born in 1932 in Prague, Czechoslovakia. In 1957 he received a M.S. degree in Electrical engineering at the Czech Technical University in Prague. In the early 1960s he taught at the Institute of Computer Research in Prague. In 1964 he received a doctorate in Computer science from the Czechoslovak Academy of Sciences.
In the 1960s Klir went to Iraq to teach at the Baghdad University for two years. At the end he managed to immigrate to the U.S. He started teaching computer science at UCLA and at the Fairleigh Dickinson University. In 1969 he came to Binghamton University, where he later became professor of Systems science. One year (1982–1983) he stayed as a fellow in Dutch Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS), where he completed the manuscript of his book Architecture of Systems Problem Solving. In 2007 he retired after 37 years at the University. One of his doctoral students was Richard Sternberg.
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George W. Bush
George Walker Bush (born July 6, 1946) is an American politician and businessman who was the 43rd President of the United States from 2001 to 2009 and the 46th Governor of Texas from 1995 to 2000. The eldest son of Barbara Bush and George H. W. Bush, he was born in New Haven, Connecticut. After graduating from Yale University in 1968 and Harvard Business School in 1975, Bush worked in oil businesses. He married Laura Welch in 1977 and ran unsuccessfully for the House of Representatives shortly thereafter. He later co-owned the Texas Rangers baseball team before defeating Ann Richards in the 1994 Texas gubernatorial election. In a close and controversial election, Bush was elected President in 2000 as the Republican candidate, defeating Vice President Al Gore in the Electoral College. Bush is the second American president to have been the son of a former president. He is also the brother of Jeb Bush, former Governor of Florida.
Terrorist attacks occurred eight months into Bush's first term as president on September 11, 2001. In response, Bush announced the War on Terror, an international military campaign which included the war in Afghanistan launched in 2001 and the war in Iraq launched in 2003. In addition to national security issues, Bush promoted policies on the economy, health care, education, and social security reform. He signed into law broad tax cuts, the PATRIOT Act, the No Child Left Behind Act, the Partial-Birth Abortion Ban Act, and Medicare prescription drug benefits for seniors. His tenure saw national debates on immigration, Social Security, electronic surveillance, and enhanced interrogation techniques. His administration also withdrew the U.S. from a some international treaty processes, including the Kyoto Protocol on global warming.
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Gregory Bateson
Gregory Bateson (9 May 1904 – 4 July 1980) was an English anthropologist, social scientist, linguist, visual anthropologist, semiotician and cyberneticist whose work intersected that of many other fields. In the 1940s he helped extend systems theory/cybernetics to the social/behavioral sciences, and spent the last decade of his life developing a "meta-science" of epistemology to bring together the various early forms of systems theory developing in various fields of science. Some of his most noted writings are to be found in his books, Steps to an Ecology of Mind (1972) and Mind and Nature (1979). Angels Fear (published posthumously in 1987) was co-authored by his daughter Mary Catherine Bateson.
Bateson was born in Grantchester in Cambridgeshire, England on 9 May 1904 - the third and youngest son of [Caroline] Beatrice Durham and of the distinguished geneticist William Bateson. The younger Bateson attended Charterhouse School from 1917 to 1921, obtained a BA in biology at St. John's College, Cambridge in 1925, and continued at Cambridge from 1927 to 1929. Bateson lectured in linguistics at the University of Sydney in 1928. From 1931 to 1937 he was a Fellow of St. John's College, Cambridge, spent the years before World War II in the South Pacific in New Guinea and Bali doing anthropology. During 1936-1950 he was married to Margaret Mead. At that time he applied his knowledge to the war effort before moving to the United States.
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Heinz von Foerster
Heinz von Foerster (born Heinz von Förster; November 13, 1911, Vienna – October 2, 2002, Pescadero, California) was an Austrian American scientist combining physics and philosophy. Together with Warren McCulloch, Norbert Wiener, John von Neumann, Lawrence J. Fogel, and others, Heinz von Foerster was an architect of cybernetics.
Von Foerster was born in 1911 in Vienna, Austria-Hungary, as Heinz von Förster. He studied physics at the Technical University of Vienna and at the University of Breslau, where in 1944 he received a Ph.D. in physics.
He moved to the USA in 1949, and worked at the University of Illinois at Urbana-Champaign, where he was a professor of electrical engineering from 1951 to 1975. From 1962 to 1975 he also was professor of biophysics and 1958–75 director of the Biological Computer Laboratory. Additionally, in 1956–57 and 1963–64 he was a Guggenheim-Fellow. From 1963 to 1965 he was president of the Wenner-Gren-Foundation for anthropological research.
He knew well and was in conversation with John von Neumann, Norbert Wiener, Humberto Maturana, Francisco Varela, Gordon Pask, Gregory Bateson, Lawrence J. Fogel and Margaret Mead, among many others. He influenced generations of students as a teacher and inclusive, enthusiastic collaborator.
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Howard T. Odum
Howard Thomas Odum (1924, Chapel Hill, North Carolina–2002 Gainesville, Florida) (also known as Tom or just H.T.) was an American ecologist. He is known for his pioneering work on ecosystem ecology, and for his provocative proposals for additional laws of thermodynamics, informed by his work on general systems theory.
Odum was the third child of the American sociologist Howard W. Odum, and the brother of Eugene Odum. Their father "encouraged his sons to go into science and to develop new techniques to contribute to social progress. Howard learned his early scientific lessons about birds from his brother, about fish and the philosophy of biology while working after school for the marine zoologist Robert Coker, and about electrical circuits from The Boy Electrician by Alfred Powell Morgan
Howard Thomas studied zoology at the University of North Carolina at Chapel Hill, where he published his first paper while still an undergraduate. His education was interrupted for three years by his World War II service with the Army Air Force in Puerto Rico and the Panama Canal Zone where he worked as a tropical meteorologist. After the war, he returned to the University of North Carolina and completed his B.S. in zoology (Phi Beta Kappa) in 1947.
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Ilya Prigogine
Ilya, Viscount Prigogine (Russian: Илья́ Рома́нович Приго́жин, Ilya Romanovich Prigozhin) (25 January 1917 – 28 May 2003) was a Belgian physical chemist and Nobel Laureate noted for his work on dissipative structures, complex systems, and irreversibility.
Prigogine was born in Moscow a few months before the Russian Revolution of 1917, into a Jewish family. His father, Roman (Ruvim Abramovich) Prigogine, was a chemical engineer at the Moscow Institute of Technology; his mother, Yulia Vikhman, was a pianist. Because the family was critical of the new Soviet system, they left Russia in 1921. They first went to Germany and in 1929, to Belgium, where Prigogine received Belgian citizenship in 1949.
Prigogine studied chemistry at the Free University of Brussels, where in 1950, he became professor. In 1959, he was appointed director of the International Solvay Institute in Brussels, Belgium. In that year, he also started teaching at the University of Texas at Austin in the United States, where he later was appointed Regental Professor and Ashbel Smith Professor of Physics and Chemical Engineering. From 1961 until 1966 he was affiliated with the Enrico Fermi Institute at the University of Chicago. In Austin, in 1967, he co-founded what is now called The Center for Complex Quantum Systems. In that year, he also returned to Belgium, where he became director of the Center for Statistical Mechanics and Thermodynamics.
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Ivan Getting
Ivan Alexander Getting (January 18, 1912—October 11, 2003) was an American physicist and electrical engineer, credited (along with Roger L. Easton and Bradford Parkinson) with the development of the Global Positioning System (GPS). He was the co-leader (the other being Louis Ridenour) of the research group which developed the SCR-584, an automatic microwave tracking fire-control system, which enabled anti-aircraft guns to destroy a significant percentage of the German V-1 flying bombs launched against London late in the Second World War.
Ivan A. Getting was born on 18 January, 1912 in New York City to family of Slovak immigrants from Bytča, Slovakia and grew up in Pittsburgh, Pennsylvania. He attended the Massachusetts Institute of Technology (MIT) as an Edison Scholar (S.B. Physics, 1933); and Oxford University as a Graduate Rhodes Scholar (D.Phil., 1935). He then worked at Harvard University on nuclear instrumentation and cosmic rays (Junior Fellow, 1935-1940) and the MIT Radiation Laboratory (1940-1950; Director of the Division on Fire Control and Army Radar, Associate Professor 1945; Professor 1946). During the Second World War he was a special consultant to Secretary of War Henry L. Stimson on the Army’s use of radar. He also served as head of the Naval Fire Control Section of the Office of Scientific Research and Development, member of the Combined Chiefs of Staff Committee on Searchlight and Fire Control, and head of the Radar Panel of the Research and Development Board of the Department of Defense.he was getting involed in world War 2.
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James Grier Miller
James Grier Miller (1916 – 7 November 2002, California) was an American biologist, a pioneer of systems science, who originated the modern use of the term "behavioral science", founded and directed the multi-disciplinary Mental Health Research Institute at the University of Michigan, and originated the living systems theory.
Miller received his A.B. summa cum laude in 1937, an A.M. in psychology in 1938, an M.D. cum laude in 1942, and Ph.D. in psychology in 1943 all from Harvard University, where he was also a junior fellow of the Society of Fellows. Following military service in World War II, he served as Chief of the newly formed Clinical Psychology section of the Veteran's Administration central office in Washington.
He has served on the faculty at Harvard. In 1948, he accepted the position of Chairman of the Department of Psychology at the University of Chicago, which he held until 1955. From 1955 to 1967 he directed the multi-disciplinary Mental Health Research Institute At Michigan. In 1967 to pursue an administrative career, first as provost of the newly founded Cleveland State University, and then in 1973 as president of the University of Louisville, from which position he retired in 1980.
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Jay Wright Forrester
Jay Wright Forrester (born July 14, 1918-) is a pioneer American computer engineer, systems scientist and was a professor at the MIT Sloan School of Management. Forrester is known as the founder of System Dynamics, which deals with the simulation of interactions between objects in dynamic systems.
Forrester was born in 1918 on a cattle ranch near Anselmo, Nebraska. His early interest in electricity was possibly sparked by the fact that the ranch had none. While in high school, he built a wind-driven 12-volt electrical system using old car parts—it gave the ranch its first electric power. After finishing high school, he had received a scholarship to go to the Agricultural College. Three weeks before enrolling, he realized a future of herding cattle in Nebraska winter blizzards had never appealed to him. So in 1936 he enrolled in the Engineering College at the University of Nebraska to study electrical engineering. As it turns out this study was about the only academic field with a solid, central core of theoretical dynamics.
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Kenneth E. Boulding
Kenneth Ewart Boulding (January 18, 1910 – March 18, 1993) was an economist, educator, peace activist, poet, religious mystic, devoted Quaker, systems scientist, and interdisciplinary philosopher. He was cofounder of General Systems Theory and founder of numerous ongoing intellectual projects in economics and social science. He was married to Elise M. Boulding.
Boulding was born in Liverpool, England in 1910. He graduated from Oxford University, and was granted United States citizenship in 1948. During the years 1949 to 1967, he was a faculty member of the University of Michigan. In 1967, he joined the faculty of the University of Colorado at Boulder, where he remained until his retirement.
Boulding was president of numerous scholarly societies including the American Economic Association, the Society for General Systems Research, and the American Association for the Advancement of Science. He was not only a prolific writer and a creative integrator of knowledge, but an academician of world stature—indeed, a magisterial figure in the discipline of social science. For Boulding, economics and sociology were not social sciences—rather, they were all aspects of a single social science devoted to the study of human persons and their relationships (organizations). Boulding spearheaded an evolutionary (instead of equilibrium) approach to economics.
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Kevin Warwick
Kevin Warwick (born 9 February 1954 Coventry, UK) is a British scientist and professor of cybernetics at the University of Reading, Reading, Berkshire, United Kingdom. He is known for his studies on direct interfaces between computer systems and the human nervous system, and has also done research in the field of robotics.
Kevin Warwick was born in 1954 in Coventry in the United Kingdom. He attended Lawrence Sheriff School in Rugby, Warwickshire. He left school in 1970 to join British Telecom, at the age of 16. In 1976 he took his first degree at Aston University, followed by a Ph.D and a research post at Imperial College London.
He subsequently held positions at Oxford, Newcastle and Warwick universities before being offered the Chair in Cybernetics at the University of Reading in 1987.
Warwick is a Chartered Engineer, a Fellow of the Institution of Engineering and Technology and a Fellow of the City and Guilds of London Institute. He is Visiting Professor at the Czech Technical University in Prague and the University of Strathclyde and in 2004 was Senior Beckman Fellow at the University of Illinois at Urbana-Champaign, USA. He is also Director of the University of Reading Knowledge Transfer Partnerships Centre, which links the University with Companies and is on the Advisory Boards of the Instinctive Computing Laboratory, Carnegie Mellon University and the Centre for Intermedia, University of Exeter.
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Margaret Mead
Margaret Mead (December 16, 1901 – November 15, 1978) was an American cultural anthropologist, who was frequently a featured writer and speaker in the mass media throughout the 1960s and 1970s. She earned her bachelor degree at Barnard College in New York City, and her M.A. and Ph.D. degrees from Columbia University.
She was both a popularizer of the insights of anthropology into modern American and Western culture and a respected, if controversial, academic anthropologist. Her reports about the attitudes towards sex in South Pacific and Southeast Asian traditional cultures amply informed the 1960s sexual revolution. Mead was a champion of broadened sexual mores within a context of traditional western religious life.
An Anglican Christian, she played a considerable part in the drafting of the 1979 American Episcopal Book of Common Prayer.
Mead, the first of five children, was born in Philadelphia, Pennsylvania, but raised in Doylestown. Her father, Edward Sherwood Mead, was a professor of finance at the Wharton School of the University of Pennsylvania, and her mother, Emily (Fogg) Mead, was a sociologist who studied Italian immigrants. Her sister Katharine (1906–1907) died at the age of nine months. This was a traumatic event for Mead, who had named this baby, and thoughts of her lost sister permeated her daydreams for many years. Her family moved frequently, so her early education alternated between home-schooling and traditional schools. Born into a family of varying religious outlooks, she searched for a form of religion that gave an expression of the faith that she had been formally acquainted with, Christianity. In doing so, she found the rituals of the Episcopal Church to fit the expression of religion she was seeking. Margaret studied one year, 1919, at DePauw University, then transferred to Barnard College where she earned her bachelor's degree in 1923.
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Mihajlo D. Mesarovic
Mihajlo D. Mesarovic (1928), (Serbian: Mihajlo D. Mesarović, Serbian Cyrillic: Михајло Д. Месаровић) is a Yugoslavian scientist, who is a professor of Systems Engineering and Mathematics at Case Western Reserve University. Mesarovic has been a pioneer in the field of systems theory, he was UNESCO Scientific Advisor on Global change and also a member of the Club of Rome.
Mihajlo D. Mesarovic was born in Yugoslavia in 1928. He was awarded the M.S. from the University of Belgrade Faculty of Electrical Engineering in 1951. In 1955 he received a Ph.D. in Technical sciences from the University of Belgrade. In 1958 he became a Sloane Post-Doctoral Fellow at MIT.
Mesarovic held academic positions at University of Belgrade, Yugoslavia form 1954 to 1958. He was associate Professor at CWRU from 1959 to 1964 and professor from 1964 to 1978. In that time he was head of the Systems Engineering Group 1965-68, head of the Systems Engineering Department 1968-72 and director of the Systems Research Center 1968-78. Starting 1978, Prof. Mesarovic has been the Cady Staley Professor of Systems Engineering and Mathematics. One of his students was Roger W. Brockett.
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Murray Bowen
Murray Bowen, M.D., (31 January 1913, Waverly, Tennessee - 9 October 1990) was an American psychiatrist and a professor in psychiatry at the Georgetown University. Bowen was among the pioneers of family therapy and founders of systemic therapy. Beginning in the 1950s, he developed a systems theory of the family.
Murray Bowen was born in 1913 as the oldest of five and grew up in the small town of Waverly, Tennessee, where his father was the mayor for some time. Bowen got his B.S. in 1934 at the University of Tennessee in Knoxville. He received his MD in 1937 at the Medical School of the University of Tennessee Medical School in Memphis. After that, he had internships at the Bellevue Hospital in New York City in 1938 and at the Grasslands Hospital, Valhalla, New York, from 1939 to 1941. From 1941 to 1946, he had his military training followed by five years of active duty with Army in the United States and Europe. During the war, his interest changed from surgery to psychiatry. While observing the soldiers he decided that mental illness was a more pressing and worthwhile goal. After his military service he had been accepted for fellowship in surgery at Mayo Clinic. But in 1946, he started at the Menninger Foundation in Topeka, Kansas, as fellow in psychiatry and personal psychoanalysis. This psychiatric training and experience lasted here until 1954.
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Niklas Luhmann
Niklas Luhmann (December 8, 1927 - November 6, 1998) was a German sociologist, and a prominent thinker in sociological systems theory.
Luhmann was born in Lüneburg, Lower Saxony, where his father's family had been running a brewery for several generations. After graduating from the Johanneum school in 1943, he was conscripted as a Luftwaffenhelfer in World War II and served for two years until, at the age of 17, he was taken prisoner of war by American troops in 1945. After the war Luhmann studied law at the University of Freiburg from 1946 to 1949, when he obtained a law degree, and then began a career in Lüneburg's public administration. During a sabbatical in 1961, he went to Harvard, where he met and studied under Talcott Parsons, then the world's most influential social systems theorist.
In later years, Luhmann dismissed Parsons' theory, developing a rival approach of his own. Leaving the civil service in 1962, he lectured at the national Deutsche Hochschule für Verwaltungswissenschaften (University for Administrative Sciences) in Speyer, Germany, until 1965, when he was offered a position at the Sozialforschungsstelle (Social Research Centre) of the University of Münster, led by Helmut Schelsky. 1965/66 he studied one semester of sociology at the University of Münster.
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Norbert Wiener
Norbert Wiener (November 26, 1894, Columbia, Missouri – March 18, 1964, Stockholm, Sweden) was an American mathematician. He was Professor of Mathematics at MIT.
A famous child prodigy, Wiener later became an early researcher in stochastic and noise processes, contributing work relevant to electronic engineering, electronic communication, and control systems.
Wiener is regarded as the originator of cybernetics, a formalization of the notion of feedback, with many implications for engineering, systems control, computer science, biology, philosophy, and the organization of society.
Wiener was the first child of Leo Wiener and Bertha Kahn, Jews of Polish and German descent, respectively. Norbert Wiener became a famous child prodigy. Leo had educated Norbert at home until 1903, employing teaching methods of his own invention, except for a brief interlude when Norbert was 7 years of age. Earning his living teaching German and Slavic languages, Leo read widely and accumulated a personal library from which the young Norbert benefited greatly. Leo also had ample ability in mathematics, and tutored his son in the subject until he left home.
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Qian Xuesen
Qian Xuesen (simplified Chinese: 钱学森; traditional Chinese: 錢學森; pinyin: Qián Xuésēn; Wade–Giles: Ch'ien Hsüeh-sên) (11 December 1911 – 31 October 2009) was a scientist who made important contributions to the missile and space programs of both the United States and People's Republic of China. Historical documents in the U. S. commonly refer to him with the earlier family-name last spelling, Hsue-Shen Tsien or H.S. Tsien.
During the 1940s Qian was one of the founders of the Jet Propulsion Laboratory at the California Institute of Technology. During the Second Red Scare of the 1950s, the United States government accused Qian of having communist sympathies, and he was stripped of his security clearance in 1950. Qian then decided to return to China, but instead was detained at Terminal Island near Los Angeles. After spending 5 years under virtual house arrest, Qian was released in 1955, in exchange for the repatriation of American pilots captured during the Korean War. Notified by U.S. authorities that he was free to go, Qian immediately arranged his departure, leaving for China in September 1955, on the passenger liner SS President Cleveland of American President Lines, via Hong Kong. He returned to lead the Chinese rocket program, and became known as the "Father of Chinese Rocketry" (or "King of Rocketry").
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Richard E. Bellman
Richard Ernest Bellman (August 26, 1920 – March 19, 1984) was an American applied mathematician, celebrated for his invention of dynamic programming in 1953, and important contributions in other fields of mathematics.
Bellman was born in 1920 in New York City, where his father John James Bellman ran a small grocery store on Bergen Street near Prospect Park in Brooklyn. Bellman completed his studies at Abraham Lincoln High School in 1937, and studied mathematics at Brooklyn College where he received a BA in 1941. He later earned an MA from the University of Wisconsin–Madison. During World War II he worked for a Theoretical Physics Division group in Los Alamos. In 1946 he received his Ph.D. at Princeton under the supervision of Solomon Lefschetz. From 1949 Bellman worked for many years at RAND corporation and it was during this time that he developed dynamic programming.
He was a professor at the University of Southern California, a Fellow in the American Academy of Arts and Sciences (1975), and a member of the National Academy of Engineering (1977).
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Roger L. Easton
Roger L. Easton (born April 30, 1921) is an American scientist. He is the principal inventor and designer of the Global Positioning System (GPS). In 1955, Easton co-wrote the Naval Research Laboratory's Project Vanguard proposal for a U.S. satellite program in competition with two other proposals, including a proposal from the U.S. Army prepared by Wernher Von Braun. The Eisenhower Administration selected Project Vanguard. Easton also invented the Minitrack tracking system to determine the Vanguard satellite's orbit. When Sputnik was launched in 1957 Easton extended the system to actively follow unknown orbiting satellites. The Naval Space Surveillance System became the first system to detect and track all types of Earth-orbiting objects.
Later in his career at NRL, Easton conceived, patented, and led the development of essential enabling technologies for the United States Global Positioning System (GPS). During the 1960s and early 1970s he developed a time-based navigational system with passive ranging, circular orbits, and space-borne high precision clocks placed in satellites. The idea was tested with four experimental satellites: TIMATION I and II (in 1967 and 1969) and Navigation Technology Satellites (NTS) 1 and 2 (in 1974 and 1977). NTS-2 was the first satellite to transmit GPS signals.
wn.com/Roger_L._Easton -
Ronald Reagan
Ronald Wilson Reagan ( /ˈrɒnəld ˈwɪlsən ˈreɪɡən/; February 6, 1911 – June 5, 2004) was the 40th President of the United States, serving from 1981 to 1989. Prior to that, he was the 33rd Governor of California from 1967 to 1975 and a radio, film and television actor.
Born in Tampico, Illinois and raised in Dixon, Reagan was educated at Eureka College, earning a Bachelor of Arts degree in economics and sociology. After his graduation, Reagan moved first to Iowa to work as a radio broadcaster and then in to Los Angeles in 1937 where he began a career as an actor, first in films and later television. Some of his most notable films include Knute Rockne, All American, Kings Row, and Bedtime for Bonzo. Reagan served as president of the Screen Actors Guild, and later as a spokesman for General Electric (GE); his start in politics occurred during his work for GE. Originally a member of the Democratic Party, his positions began shifting rightward in the late 1950s, and he switched to the Republican Party in 1962. After delivering a rousing speech in support of Barry Goldwater's presidential candidacy in 1964, he was persuaded to seek the California governorship, winning two years later and again in 1970. He was defeated in his run for the Republican presidential nomination in 1968 as well as 1976, but won both the nomination and general election in 1980, defeating incumbent Jimmy Carter.
wn.com/Ronald_Reagan -
Russell L. Ackoff
Russell Lincoln Ackoff (12 February 1919 – 29 October 2009) was an American organizational theorist, consultant, and Anheuser-Busch Professor Emeritus of Management Science at the Wharton School, University of Pennsylvania. Ackoff was a pioneer in the field of operations research, systems thinking and management science.
Russell L. Ackoff was born in 1919 in Philadelphia to Jack and Fannie (Weitz) Ackoff. He received his bachelor degree in architecture at the University of Pennsylvania in 1941. After graduation, he taught at Penn for one year as an assistant instructor in philosophy. From 1942 to 1946, he served in the U.S. Army. He returned to study at the University of Pennsylvania, where he received his doctorate in philosophy of science in 1947 as C. West Churchman’s first doctoral student. He also received a number of honorary doctorates, from 1967 and onward.
From 1947 to 1951 Ackoff was assistant professor in philosophy and mathematics at the Wayne State University. He was associate professor and professor of operations research at Case Institute of Technology from 1951 to 1964. In 1961 and 1962 he was also visiting professor of operational research at the University of Birmingham. From 1964 to 1986 he was professor of systems sciences and professor of management science at the Wharton School at the University of Pennsylvania.
wn.com/Russell_L._Ackoff -
Talcott Parsons
Talcott Parsons (December 13, 1902 – May 8, 1979) was an American sociologist who served on the faculty of Harvard University from 1927 to 1973.
Parsons developed a general theory for the study of society called action theory, based on the methodological principle of voluntarism and the epistemological principle of analytical realism. The theory attempted to establish a balance between two major methodological traditions: the utilitarian-positivist and hermeneutic-idealistic traditions. For Parsons, voluntarism established a third alternative between these two. More than a theory of society, Parsons presented a theory of social evolution and a concrete interpretation of the "drives" and directions of world history.
Parsons analyzed the work of Émile Durkheim and Vilfredo Pareto and evaluated their contributions through the paradigm of voluntaristic action. Parsons was also largely responsible for introducing and interpreting Max Weber's work to American audiences. Although he was generally considered a major structuralist functionalist scholar, in an article late in life, Parsons explicitly wrote that the term "functional" or "structural functionalist" were inappropriate ways to describe the character of his theory. For Parsons, "structural functionalism" was a particular stage in the methodological development of the social science, and "functionalism" was a universal method; neither term was a name for any specific school. In the same way, the concept "grand theory" is a derogatory term, which Parsons himself never used.
wn.com/Talcott_Parsons -
William Perry
William James Perry (born October 11, 1927) is an American businessman and engineer who was the United States Secretary of Defense from February 3, 1994, to January 23, 1997, under President Bill Clinton. He also served as Deputy Secretary of Defense (1993–1994) and Under Secretary of Defense for Research and Engineering (1977-1981).
Perry is currently the Michael and Barbara Berberian Professor at Stanford University, with a joint appointment in the School of Engineering. He is also a senior fellow at Stanford University's Hoover Institution. He is a senior fellow at the Freeman Spogli Institute for International Studies and serves as co-director of the Nuclear Risk Reduction initiative and the Preventive Defense Project. He is an expert in U.S. foreign policy, national security and arms control.
Former Secretary Perry also has extensive business experience and currently serves on the boards of several high-tech companies and is Chairman of Global Technology Partners. He is a member of the National Academy of Engineering and a fellow of the American Academy of Arts and Sciences. Among Perry's numerous awards are the Presidential Medal of Freedom (1997), Knight Commander of the Order of the British Empire (1998) and the Grand Cordon of the Order of the Rising Sun (2002), awarded by the Emperor of Japan.
wn.com/William_Perry -
William Ross Ashby
W. Ross Ashby (London, 6 September 1903 – 15 November 1972) was an English psychiatrist and a pioneer in cybernetics, the study of complex systems. His first name was not used: he was known as Ross Ashby.
His two books, Design for a brain and An introduction to cybernetics, were landmark works. They introduced exact and logical thinking to the nascent discipline, and were highly influential.
William Ross Ashby was born in 1903 in London, where his father was working at an advertising agency. From 1917 to 1921 William studied at the Edinburgh Academy in Scotland, and from 1921 at Sidney Sussex College, Cambridge, where he received his B.A. in 1924 and his M.B. and B.Ch. in 1928. From 1924 to 1928 he worked at the St. Bartholomew's Hospital in London. Later on he also received a Diploma in Psychological Medicine in 1931, and an M.A. 1930 and M.D. from Cambridge in 1935.
Ross Ashby started working in 1930 as a Clinical Psychiatrist in the London County Council. From 1936 until 1947 he was a Research Pathologist in the St Andrew's Hospital in Northampton in England. From 1945 to 1947 he served in India where he was a Major in the Royal Army Medical Corps.
wn.com/William_Ross_Ashby
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How GPS works
- Order: Reorder
- Duration: 5:11
- Updated: 07 Dec 2012
The GPS network and how gravity affects time and space. The military operations needed behind the system to keep it in check.
http://wn.com/How_GPS_works
The GPS network and how gravity affects time and space. The military operations needed behind the system to keep it in check.
Garmin Etrex H Handheld GPS Sat Nav Review
- Order: Reorder
- Duration: 8:26
- Updated: 19 Nov 2012
Quick review of the new Garmin Etrex h (high sensitivity GPS Reciever) www.sciuridae.co.uk webmaster: scalsepeeder
http://wn.com/Garmin_Etrex_H_Handheld_GPS_Sat_Nav_Review
Quick review of the new Garmin Etrex h (high sensitivity GPS Reciever) www.sciuridae.co.uk webmaster: scalsepeeder
- published: 23 Apr 2011
- views: 41631
- author: scalespeeder
The Truth About GPS: How it works
- Order: Reorder
- Duration: 3:11
- Updated: 25 Nov 2012
Col. David Buckman, Air Force Space Command, talks about GPS, how it works, and modernization.
http://wn.com/The_Truth_About_GPS_How_it_works
Col. David Buckman, Air Force Space Command, talks about GPS, how it works, and modernization.
- published: 03 Feb 2010
- views: 46923
- author: airforcespacecommand
Global Positioning System
- Order: Reorder
- Duration: 3:35
- Updated: 08 Oct 2012
This NASA produced short film (3:30) describes the Global Positioning System. It is a great summary and can be used to augment the Galaxy Explorers Mission Plan on GPS.
http://wn.com/Global_Positioning_System
This NASA produced short film (3:30) describes the Global Positioning System. It is a great summary and can be used to augment the Galaxy Explorers Mission Plan on GPS.
- published: 31 Dec 2006
- views: 91386
- author: galaxyexplorers
GPS
- Order: Reorder
- Duration: 1:28
- Updated: 08 Dec 2012
I was under the impression that GPS was supposed to make your life easier...
http://wn.com/GPS
I was under the impression that GPS was supposed to make your life easier...
- published: 15 Sep 2009
- views: 361434
- author: sheepfilms
Is Garmin GPS King? - 2008 GPS Navigation Comparison Video
- Order: Reorder
- Duration: 4:45
- Updated: 16 Nov 2012
www.edmunds.com You've got a busy summer ahead. Before setting out on that road trip out West or back East, you'll have to find time to download some travel music. (We recommend new releases from Common, My Morning Jacket and Weezer.) After that, we've got another assignment for you that promises to make your summer trip easier and may enhance your listening habits, too: Get a portable navigation system. Of course, we wouldn't dream of leaving you out in the cold on such an important decision, so we're updating last year's portable navigation system roundup with four new or newly improved portable systems. Since our last portable navigation review, a few of the units we sampled have changed significantly, plus there are two all-new units that seem promising on paper — the Dash Express and Becker Travel Assistant.
http://wn.com/Is_Garmin_GPS_King?_2008_GPS_Navigation_Comparison_Video
www.edmunds.com You've got a busy summer ahead. Before setting out on that road trip out West or back East, you'll have to find time to download some travel music. (We recommend new releases from Common, My Morning Jacket and Weezer.) After that, we've got another assignment for you that promises to make your summer trip easier and may enhance your listening habits, too: Get a portable navigation system. Of course, we wouldn't dream of leaving you out in the cold on such an important decision, so we're updating last year's portable navigation system roundup with four new or newly improved portable systems. Since our last portable navigation review, a few of the units we sampled have changed significantly, plus there are two all-new units that seem promising on paper — the Dash Express and Becker Travel Assistant.
- published: 14 Jun 2008
- views: 88116
- author: InsideLineVideo
Garmin Nuvi 205 GPS
- Order: Reorder
- Duration: 10:28
- Updated: 17 Nov 2012
Portable and affordable, nüvi 205 is your personal travel assistant for life on the go. This navigator leads the way with turn-by-turn directions and optional MSN® Direct services to get you there on time and keep you informed. It's packed with millions of destinations and maps for the contiguous US Like the rest of the compact nüvi 2x5-series, the 205 is priced right and ultra-easy to use.
http://wn.com/Garmin_Nuvi_205_GPS
Portable and affordable, nüvi 205 is your personal travel assistant for life on the go. This navigator leads the way with turn-by-turn directions and optional MSN® Direct services to get you there on time and keep you informed. It's packed with millions of destinations and maps for the contiguous US Like the rest of the compact nüvi 2x5-series, the 205 is priced right and ultra-easy to use.
- published: 14 Oct 2008
- views: 221356
- author: TigerDirectBlog
Magellan GPS Navigation Premium Car Kit Pre-Release In-Car / On-Road Review (iPhone or iPod Touch)
- Order: Reorder
- Duration: 6:30
- Updated: 25 Nov 2012
Check out this pre-release in-car / on-road review of the Magellan Premium Car Kit for iPhone 3G/3GS or iPod Touch 2G's. This kit is scheduled to be released on January 7th, 2010, so here's your chance to get a closer look at what to expect when this thing hits the shelves next year. A VERY cool kit with lots of innovative features, and awesome form factor. Enjoy, and thanks for looking! From Magellan's website: Transform your iPhone®(3G or 3GS) or iPod touch®(2nd generation) into a complete in-car GPS navigation solution with the Magellan® Premium Car Kit. • Turns your iPod touch (2nd Generation) into a GPS Navigator Built-in GPS receiver allows navigation on an iPod touch (2nd Generation). • Adjustable mount accommodates most skins and hard cases Accommodates most cases or skins for maximum flexibility when inserting into the cradle. Simply pop your iPhone or iPod touch in the mount and you are ready to go! • Rotates for both portrait and landscape use Quickly secure the cradle to your windshield or dashboard and easily adjust for portrait or landscape viewing. • Enhanced signal with built in GPS receiver Build in GPS Receiver Enhances Performance. A powerful, sensitive, built-in GPS receiver for fast and accurate directions. • In-car charging The cradle automatically powers and charges your iPhone or iPod touch when connected. No need to worry about running out of battery power. • Noise cancelling speakerphone For crystal clear calls. • Bluetooth hands-free calling ...
http://wn.com/Magellan_GPS_Navigation_Premium_Car_Kit_Pre-Release_In-Car_On-Road_Review_iPhone_or_iPod_Touch
Check out this pre-release in-car / on-road review of the Magellan Premium Car Kit for iPhone 3G/3GS or iPod Touch 2G's. This kit is scheduled to be released on January 7th, 2010, so here's your chance to get a closer look at what to expect when this thing hits the shelves next year. A VERY cool kit with lots of innovative features, and awesome form factor. Enjoy, and thanks for looking! From Magellan's website: Transform your iPhone®(3G or 3GS) or iPod touch®(2nd generation) into a complete in-car GPS navigation solution with the Magellan® Premium Car Kit. • Turns your iPod touch (2nd Generation) into a GPS Navigator Built-in GPS receiver allows navigation on an iPod touch (2nd Generation). • Adjustable mount accommodates most skins and hard cases Accommodates most cases or skins for maximum flexibility when inserting into the cradle. Simply pop your iPhone or iPod touch in the mount and you are ready to go! • Rotates for both portrait and landscape use Quickly secure the cradle to your windshield or dashboard and easily adjust for portrait or landscape viewing. • Enhanced signal with built in GPS receiver Build in GPS Receiver Enhances Performance. A powerful, sensitive, built-in GPS receiver for fast and accurate directions. • In-car charging The cradle automatically powers and charges your iPhone or iPod touch when connected. No need to worry about running out of battery power. • Noise cancelling speakerphone For crystal clear calls. • Bluetooth hands-free calling ...
- published: 27 Dec 2009
- views: 137913
- author: ShaneXman
GPS Principles Video
- Order: Reorder
- Duration: 4:06
- Updated: 27 Oct 2012
This video explains the principles behind Trimble GPS.
http://wn.com/GPS_Principles_Video
This video explains the principles behind Trimble GPS.
- published: 25 Apr 2008
- views: 26333
- author: Zoe Schumacher
Garmin nuvi 1390T GPS Video Walkthrough
- Order: Reorder
- Duration: 6:44
- Updated: 04 Dec 2012
Video review of Garmin's nuvi 1390T
http://wn.com/Garmin_nuvi_1390T_GPS_Video_Walkthrough
Video review of Garmin's nuvi 1390T
- published: 01 Jul 2009
- views: 186234
- author: gpsmagazine
Darth Vader recording for TomTom GPS - behind the scenes
- Order: Reorder
- Duration: 2:27
- Updated: 08 Dec 2012
Lord Vader commands you to turn to the Dark Side. Will you be able to resist as he guides you to your destination? Get the voice at www.tomtom.com TomTom Gives You More - redeem your game code: YTDARKSIDE here www.tomtom.com
http://wn.com/Darth_Vader_recording_for_TomTom_GPS_behind_the_scenes
Lord Vader commands you to turn to the Dark Side. Will you be able to resist as he guides you to your destination? Get the voice at www.tomtom.com TomTom Gives You More - redeem your game code: YTDARKSIDE here www.tomtom.com
- published: 04 May 2010
- views: 5092753
- author: TomTomOfficial
How To Update Maps On Garmin GPS For FREE
- Order: Reorder
- Duration: 5:26
- Updated: 08 Dec 2012
I will not directly link to the files, because they are copy-written. This video is strictly for the purpose of installing backed-up map files or custom map files. I DO NOT CONDONE PIRACY. if you are looking for 2012 map files because your backup was damaged, i would search thepiratebay.se the mac doesn't seem to completely delete the old map file off the device Garmin 1300, 1350 and 1490 users!! The "gmapprom.img" file is no longer in the root directory of your gps. Garmin does this on purpose so that you don't get yo maps for free! Here's the secret location of the gmapprom: There is a hidden folder on your device called ".SYSTEM" ... its so hidden that even if you've got "view hidden folders" enabled, you still won't be able to see it. You can get to that folder using your address bar: "H:\.System" (replace H with your drive letter)
http://wn.com/How_To_Update_Maps_On_Garmin_GPS_For_FREE
I will not directly link to the files, because they are copy-written. This video is strictly for the purpose of installing backed-up map files or custom map files. I DO NOT CONDONE PIRACY. if you are looking for 2012 map files because your backup was damaged, i would search thepiratebay.se the mac doesn't seem to completely delete the old map file off the device Garmin 1300, 1350 and 1490 users!! The "gmapprom.img" file is no longer in the root directory of your gps. Garmin does this on purpose so that you don't get yo maps for free! Here's the secret location of the gmapprom: There is a hidden folder on your device called ".SYSTEM" ... its so hidden that even if you've got "view hidden folders" enabled, you still won't be able to see it. You can get to that folder using your address bar: "H:\.System" (replace H with your drive letter)
- published: 24 Nov 2010
- views: 954013
- author: NerdHelpDesk
Personalized GPS
- Order: Reorder
- Duration: 2:23
- Updated: 26 Nov 2012
Personalized GPS to fit your lifestyle. Note: We at Tasteless Choice apologize to anyone who we have not yet offended. We're trying our best to get to all of you.
http://wn.com/Personalized_GPS
Personalized GPS to fit your lifestyle. Note: We at Tasteless Choice apologize to anyone who we have not yet offended. We're trying our best to get to all of you.
- published: 20 Jun 2008
- views: 148418
- author: TastelessChoice
What GPS Thinks
- Order: Reorder
- Duration: 2:50
- Updated: 22 Nov 2012
What does your GPS really think about you? www.gpsmaniac.com Thanks to GPSManiac for sponsoring this video!
http://wn.com/What_GPS_Thinks
What does your GPS really think about you? www.gpsmaniac.com Thanks to GPSManiac for sponsoring this video!
- published: 06 Apr 2007
- views: 72168
- author: nalts
What is GPS+ Technology?
- Order: Reorder
- Duration: 5:57
- Updated: 01 Dec 2012
Animated movie about how GPS + Glonass Technolgy works. Basic overview for how GPS technology is utilized in the field
http://wn.com/What_is_GPS+_Technology?
Animated movie about how GPS + Glonass Technolgy works. Basic overview for how GPS technology is utilized in the field
- published: 12 Jan 2007
- views: 53960
- author: TopconRULES
Samsung Galaxy S2 vs HTC Desire S - GPS Test
- Order: Reorder
- Duration: 3:29
- Updated: 05 Dec 2012
Here is a quick demo using an application called GPS Test on both the Galaxy S2 and Desire S follow me :) www.twitter.com/samjpullen
http://wn.com/Samsung_Galaxy_S2_vs_HTC_Desire_S_GPS_Test
Here is a quick demo using an application called GPS Test on both the Galaxy S2 and Desire S follow me :) www.twitter.com/samjpullen
- published: 10 May 2011
- views: 212153
- author: samjpullen
How GPS works
- Order: Reorder
- Duration: 9:57
- Updated: 03 Dec 2012
This video gives you a simple overview of the current GPS system and how it works. It also introduces other GPS systems from, Russia, Europe and China.
http://wn.com/How_GPS_works
This video gives you a simple overview of the current GPS system and how it works. It also introduces other GPS systems from, Russia, Europe and China.
- published: 20 Nov 2009
- views: 39803
- author: alantalkstech
Using Google Maps with your Garmin GPS Device
- Order: Reorder
- Duration: 1:44
- Updated: 06 Dec 2012
Follow along with Jake from the Garmin Blog Team as he shows users how to send Google Map information directly to your Garmin GPS device. Visit garmin.blogs.com for more information.
http://wn.com/Using_Google_Maps_with_your_Garmin_GPS_Device
Follow along with Jake from the Garmin Blog Team as he shows users how to send Google Map information directly to your Garmin GPS device. Visit garmin.blogs.com for more information.
- published: 03 Apr 2008
- views: 510251
- author: garminblog
GPS on PMS
- Order: Reorder
- Duration: 1:32
- Updated: 14 Nov 2012
My GPS started copping an attitude with me because it was on PMS. Luckily I captured it on tape
http://wn.com/GPS_on_PMS
My GPS started copping an attitude with me because it was on PMS. Luckily I captured it on tape
- published: 20 Jun 2006
- views: 116952
- author: nalts
Poor Man's GPS
- Order: Reorder
- Duration: 3:09
- Updated: 20 Nov 2012
Spencer becomes a suitable replacement to my broken GPS. Until... Thanks to GPS Maniac for supporting this video. www.gpsmaniac.com Music by King Fu Bootstrap Studio, Hollywood Executive Producer- Dana Fisher Producer- Lester Craft A production of www.willvideoforfood.com for GPSManiac.com
http://wn.com/Poor_Man's_GPS
Spencer becomes a suitable replacement to my broken GPS. Until... Thanks to GPS Maniac for supporting this video. www.gpsmaniac.com Music by King Fu Bootstrap Studio, Hollywood Executive Producer- Dana Fisher Producer- Lester Craft A production of www.willvideoforfood.com for GPSManiac.com
- published: 20 Sep 2007
- views: 149470
- author: nalts
Bert and Ernie recording for TomTom GPS - behind the scenes
- Order: Reorder
- Duration: 2:37
- Updated: 07 Dec 2012
Grab your rubber duckie and let Bert and Ernie show you the way to Sesame Street or any place you want to go! Get the voice at www.tomtom.com
http://wn.com/Bert_and_Ernie_recording_for_TomTom_GPS_behind_the_scenes
Grab your rubber duckie and let Bert and Ernie show you the way to Sesame Street or any place you want to go! Get the voice at www.tomtom.com
- published: 07 Nov 2011
- views: 751518
- author: TomTomOfficial
Tomorrow (GPS)
- Order: Reorder
- Duration: 1:10
- Updated: 19 Nov 2012
Overall winner of the Mofilm 2010 Pepsi Short Film Competition. www.mofilm.com Credits: Henry Nixon - Man Emma Lung - Woman Damon Herriman - GPS Abe Forsythe - Writer/Director/Editor/DOP Matt Reeder - Producer
http://wn.com/Tomorrow_GPS
Overall winner of the Mofilm 2010 Pepsi Short Film Competition. www.mofilm.com Credits: Henry Nixon - Man Emma Lung - Woman Damon Herriman - GPS Abe Forsythe - Writer/Director/Editor/DOP Matt Reeder - Producer
- published: 19 Feb 2010
- views: 47842
- author: AbeForsythe
How Does GPS Work (2005)
- Order: Reorder
- Duration: 4:27
- Updated: 07 Dec 2012
Credit: NASA LaRC Office of Education Fourth segment of NASA Sci Files The Case of the Technical Knockout explaining how GPS receivers work with satellites to determine an exact location. This segment explains the concept of trilateration in two and three dimensions.
http://wn.com/How_Does_GPS_Work_2005
Credit: NASA LaRC Office of Education Fourth segment of NASA Sci Files The Case of the Technical Knockout explaining how GPS receivers work with satellites to determine an exact location. This segment explains the concept of trilateration in two and three dimensions.
- published: 15 Feb 2012
- views: 11222
- author: airboyd
photo: AP / Photo
06 Dec 2012
Lionel Messi missed out on a chance to match Gerd Mueller's record of 85 goals in a calendar year as he was injured during Barcelona's draw with Benfica. Messi, who hurt his left knee in a collision with Benfica keeper Artur, was taken off 30 minutes after coming on as a second-half substitute. Benfica knew a win would see them finish second behind Barca in Group G ... FC Barcelona's official Twitter account tweeted after the Benfica game....(size: 2.5Kb)
photo: AP / Bullit Marquez
06 Dec 2012
NEW BATAAN, Philippines - A powerful typhoon that washed away emergency shelters, a military camp and possibly entire families in the southern Philippines has killed almost 350 people with nearly 400 missing, authorities said Thursday. More bodies were retrieved from hardest-hit Compostela Valley and Davao Oriental provinces and six others impacted by Tuesday's storm, the Office of Civil Defense reported ... "It was horrible ... --- ... Location....(size: 8.0Kb)
photo: AP / Vahid Salemi
07 Dec 2012
Article by WN.com Correspondent Dallas Darling. The in- and out-fighting between present-day Saudi Arabia and Iran is a mirror image of what occurred to Prophet Muhammad's Islamic Movement right after his death ... Still, and due to prosperity and wealth, an influx of trade goods, religious toleration, an emphasis on learning, and increased food supplies, Islam was becoming a vast empire ... Recent U.S ... Dallas Darling (darling@wn.com)....(size: 7.5Kb)
photo: AP / Osama Faisal
08 Dec 2012
There has been a historic shift in the UN climate talks in Qatar, with the prospect of rich nations having to compensate poor nations for losses due to climate change. The US has fiercely opposed the measure - it says the cost could be unlimited. But after angry tussles throughout the night the principle of Loss and Damage is now in the final negotiating text ... The political stakes are high ... "I will block this ... "I will block this ... ....(size: 3.1Kb)
Denver Post
09 Dec 2012
The New York Times
09 Dec 2012
Yellowstone National Park’s best-known wolf, beloved by many tourists and valued by scientists who tracked its movements, was shot and killed on Thursday outside the park’s boundaries, Wyoming wildlife officials reported. Enlarge This Image ... The wolf was fitted with a $4,000 collar with GPS tracking technology, which is being returned, said Daniel Stahler, a project director for Yellowstone’s wolf program ... campaign ... ....(size: 7.8Kb)
The Guardian
09 Dec 2012
Women bishops will happen, believes one of the Church of England's first female priests. Phillippa Boardman, vicar of St Paul Old Ford church in east London, wears purple under her jacket in support of women bishops. Photograph. Antonio Olmos for the Observer ... "I think in this community people are so used to both men and women being GPs and head-teachers that they are mystified by the fact that it's different in the church," she says ... ....(size: 7.4Kb)
The New York Times
09 Dec 2012
LOS ANGELES — The small, open-hull fishing boats head north from Baja Mexico, traveling at night, their navigation lights off. It is an old smuggling route, popular with tequila runners during Prohibition in the 1920s and then little used for nearly a century ... The authorities in San Diego said last year that they had found a boat equipped with a GPS device, which led them to a cache of fuel drums tied to buoys 50 miles offshore ... ....(size: 10.5Kb)
New York Daily News
09 Dec 2012
After watching Phil Simms do his thing for all these years he can never be accused of holding back. Opinionated, at times controversial (remember un-elite Eli?) and always passionate, the former Giants QB is inclined to let it rip. Or is he? ... “It would be the really raw truth. It would be fun to do.” ... Simms ... Simms ... Instead, the program opened with James Brown happily hyping a GPS sponsor, followed by five minutes of routine football talk....(size: 8.1Kb)
The Examiner
08 Dec 2012
(SAIC), El Segundo, Calif., is being awarded a $14 million contract modification for system engineering and integration services on the Global Positioning System (GPS) ... New GPS IIF satellite operational ... The GPS IIF-3 satellite, now designated SVN-65, is being ... Boeing is providing a total of 12 GPS IIFs to the U.S....(size: 1.6Kb)
Yahoo Daily News
08 Dec 2012
Save 20% to 25% off the new Polar RC3 GPS watch, the first ever fully integrated GPS watch from Polar, at the Heart Rate Watch Company now through December 21st. Bozeman, MT (PRWEB) December 08, 2012 The Polar RC3 is the first-ever fully integrated GPS watch from the folks at Polar, the same people that invented the heart rate monitor back in the 1970's....(size: 1.9Kb)
PR Newswire
08 Dec 2012
Two Wisconsin inventors have developed and successfully patented CrimeAware™, a product that provides real-time crime data on web-connected smartphones and GPS units ... 7, 2012 /PRNewswire/ -- Two Wisconsin inventors have developed and successfully patented CrimeAware™, a product that provides real-time crime data on web-connected smartphones and GPS units....(size: 4.5Kb)
Houston Chronicle
08 Dec 2012
The Heart Rate Watch Company is offering a free Garmin speed and cadence sensor valued at $50 through September 21st on several different Garmin GPS watches ... The free cadence sensor allows cycling compatible products to provide pedal cadence metrics, along with speed if a wheel magnet is desired in lieu of GPS ... Heart Rate Watch Company Offers Free Cadence Sensor With Garmin GPS Watches Thru December 21st....(size: 11.4Kb)
Daily Finance
08 Dec 2012
Every Friday, we scan the weekly ads, deal sites and retailer marketing emails to find the best deals available for the coming week. Here are a few of the best freebies and limited-time offers we found ... To get the deal, just order via the Domino's site and punch in the coupon code 50OFF ... • Gap (nyse.GPS) offers 30% off your entire purchase when you use the coupon code GAPWRAP ... AAPL BBY GPS TGT Manage Your Portfolio. ....(size: 2.4Kb)
The Times of India
08 Dec 2012
Planning a trip is fun. But, what trips many people up is the packing. Remember there is little you really need when you travel. Always ask yourself the simple question, "Do I want it or do I need it? Am I willing to cart it around?" Keep it simple and essential ... Mobile phone charger ... Sunscreen ... Flip flops ... A book ... Activate GPS on phone. With the advent of GPS and Google Maps, it's no longer necessary to carry maps of places you're visiting ... ....(size: 3.5Kb)
Canberra Times
08 Dec 2012
Yearning … Peter Liston wants contact with the children he helped create. Photo. Penny Stephens. Peter Liston has led a full life. He is a father of three, grandfather of two, and has travelled the world extensively as a professional gambler, making millions along the way ... He was paid $100 to cover his costs ... All the Health Department did was send some mini posters and pamphlets to GPs. GPs are inundated with information all the time....(size: 3.9Kb)
Yahoo Daily News
08 Dec 2012
We’ve all been there, standing in the aisle of a store, spending way too much time weighing the small differences between two similar products ... GPS Heart-Rate-Monitor Watches Garmin Forerunner 610 / garmin.comWorth it ... This heart-rate-monitor watch with GPS has a weatherproof touchscreen that can be used while wearing gloves and lets runners wirelessly upload workouts and track them online ... Timex Ironman Global Trainer With GPS ($360) ... ....(size: 6.6Kb)
"GPS" redirects here. For other uses, see GPS (disambiguation).
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This article's use of external links may not follow Wikipedia's policies or guidelines. Please improve this article by removing excessive or inappropriate external links, and converting useful links where appropriate into footnote references. (January 2012) |
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The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver.
The GPS program provides critical capabilities to military, civil and commercial users around the world. In addition, GPS is the backbone for modernizing the global air traffic system.
The GPS project was developed in 1973 to overcome the limitations of previous navigation systems,[1] integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the U.S. Department of Defense (DoD) and was originally run with 24 satellites. It became fully operational in 1994.
Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS system and implement the next generation of GPS III satellites and Next Generation Operational Control System (OCX).[2] Announcements from the Vice President and the White House in 1998 initiated these changes. In 2000, U.S. Congress authorized the modernization effort, referred to as GPS III.
In addition to GPS, other systems are in use or under development. The Russian GLObal NAvigation Satellite System (GLONASS) was in use by only the Russian military, until it was made fully available to civilians in 2007. There are also the planned European Union Galileo positioning system, Chinese Compass navigation system, and Indian Regional Navigational Satellite System.
Contents |
History[link]
The design of GPS is based partly on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator developed in the early 1940s, and used during World War II. In 1956, Friedwardt Winterberg[3] proposed a test of general relativity (for time slowing in a strong gravitational field) using accurate atomic clocks placed in orbit inside artificial satellites. (To achieve accuracy requirements, GPS uses principles of general relativity to correct the satellites' atomic clocks.[4]) Additional inspiration for GPS came when the Soviet Union launched the first man-made satellite, Sputnik in 1957. Two American physicists, William Guier and George Weiffenbach, at Johns Hopkins's Applied Physics Laboratory (APL), decided on their own to monitor Sputnik's radio transmissions.[5] Within hours they realized that, because of the Doppler effect, they could pinpoint where the satellite was along its orbit from the Doppler shift. The Director of the APL gave them access to their UNIVAC to do the heavy calculations required. When they released the orbit of Sputnik to the media, the Russians were dumbfounded to learn how powerful American computers had become, as they would not have been able to calculate the orbit themselves. The following spring, Frank McClure, the deputy director of the APL, asked Guier and Weiffenbach to look at the inverse problem where you know the location of the satellite and you want to find your own location. (The Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the Transit system.[6]
| Official logo for NAVSTAR GPS |  |
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Official logo for NAVSTAR GPS
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Emblem of the 50th Space Wing
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The first satellite navigation system, Transit (satellite), used by the United States Navy, was first successfully tested in 1960. It used a constellation of five satellites and could provide a navigational fix approximately once per hour. In 1967, the U.S. Navy developed the Timation satellite that proved the ability to place accurate clocks in space, a technology required by GPS. In the 1970s, the ground-based Omega Navigation System, based on phase comparison of signal transmission from pairs of stations,[7] became the first worldwide radio navigation system. Limitations of these systems drove the need for a more universal navigation solution with greater accuracy.
While there were wide needs for accurate navigation in military and civilian sectors, almost none of those were seen as justification for the billions of dollars it would cost in research, development, deployment, and operation for a constellation of navigation satellites. During the Cold War arms race, the nuclear threat to the existence of the United States was the one need that did justify this cost in the view of the United States Congress. This deterrent effect is why GPS was funded. It is also the reason for the ultra secrecy at that time. The nuclear triad consisted of the United States Navy's submarine-launched ballistic missiles (SLBMs) along with United States Air Force (USAF) strategic bombers and intercontinental ballistic missiles (ICBMs). Considered vital to the nuclear deterrence posture, accurate determination of the SLBM launch position was a force multiplier.
Precise navigation would enable United States submarines to get an accurate fix of their positions prior to launching their SLBMs.[8] The USAF with two-thirds of the nuclear triad also had requirements for a more accurate and reliable navigation system. The Navy and Air Force were developing their own technologies in parallel to solve what was essentially the same problem. To increase the survivability of ICBMs, there was a proposal to use mobile launch platforms (such as Russian SS-24 and SS-25) and so the need to fix the launch position had similarity to the SLBM situation.
In 1960, the Air Force proposed a radio-navigation system called MOSAIC (MObile System for Accurate ICBM Control) that was essentially a 3-D LORAN. A follow-on study called Project 57 was worked in 1963 and it was "in this study that the GPS concept was born." That same year the concept was pursued as Project 621B, which had "many of the attributes that you now see in GPS"[9] and promised increased accuracy for Air Force bombers as well as ICBMs. Updates from the Navy Transit system were too slow for the high speeds of Air Force operation. The Navy Research Laboratory continued advancements with their Timation (Time Navigation) satellites, first launched in 1967, and with the third one in 1974 carrying the first atomic clock into orbit.[10]
With these parallel developments in the 1960s, it was realized that a superior system could be developed by synthesizing the best technologies from 621B, Transit, Timation, and SECOR in a multi-service program.
During Labor Day weekend in 1973, a meeting of about 12 military officers at the Pentagon discussed the creation of a Defense Navigation Satellite System (DNSS). It was at this meeting that "the real synthesis that became GPS was created." Later that year, the DNSS program was named Navstar. With the individual satellites being associated with the name Navstar (as with the predecessors Transit and Timation), a more fully encompassing name was used to identify the constellation of Navstar satellites, Navstar-GPS, which was later shortened simply to GPS.[11]
After Korean Air Lines Flight 007, carrying 269 people, was shot down in 1983 after straying into the USSR's prohibited airspace,[12] in the vicinity of Sakhalin and Moneron Islands, President Ronald Reagan issued a directive making GPS freely available for civilian use, once it was sufficiently developed, as a common good.[13] The first satellite was launched in 1989, and the 24th satellite was launched in 1994.
Initially, the highest quality signal was reserved for military use, and the signal available for civilian use was intentionally degraded (Selective Availability). This changed with President Bill Clinton ordering Selective Availability to be turned off at midnight May 1, 2000, improving the precision of civilian GPS from 100 meters (330 ft) to 20 meters (66 ft). The executive order signed in 1996 to turn off Selective Availability in 2000 was proposed by the US Secretary of Defense, William Perry, because of the widespread growth of differential GPS services to improve civilian accuracy and eliminate the US military advantage. Moreover, the US military was actively developing technologies to deny GPS service to potential adversaries on a regional basis.[14]
Over the last decade, the U.S. has implemented several improvements to the GPS service, including new signals for civil use and increased accuracy and integrity for all users, all while maintaining compatibility with existing GPS equipment.
GPS modernization [15] has now become an ongoing initiative to upgrade the Global Positioning System with new capabilities to meet growing military, civil, and commercial needs. The program is being implemented through a series of satellite acquisitions, including GPS Block III and the Next Generation Operational Control System (OCX). The U.S. Government continues to improve the GPS space and ground segments to increase performance and accuracy.
GPS is owned and operated by the United States Government as a national resource. Department of Defense (DoD) is the steward of GPS. Interagency GPS Executive Board (IGEB) oversaw GPS policy matters from 1996 to 2004. After that the National Space-Based Positioning, Navigation and Timing Executive Committee was established by presidential directive in 2004 to advise and coordinate federal departments and agencies on matters concerning the GPS and related systems. The executive committee is chaired jointly by the deputy secretaries of defense and transportation. Its membership includes equivalent-level officials from the departments of state, commerce, and homeland security, the joint chiefs of staff, and NASA. Components of the executive office of the president participate as observers to the executive committee, and the FCC chairman participates as a liaison.
The DoD is required by law to "maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis," and "develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses."
Timeline and modernization[link]
| Block | Launch Period |
Satellite launches | Currently in orbit and healthy |
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|---|---|---|---|---|---|---|
| Suc- cess |
Fail- ure |
In prep- aration |
Plan- ned |
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| I | 1978–1985 | 10 | 1 | 0 | 0 | 0 |
| II | 1989–1990 | 9 | 0 | 0 | 0 | 0 |
| IIA | 1990–1997 | 19 | 0 | 0 | 0 | 10 |
| IIR | 1997–2004 | 12 | 1 | 0 | 0 | 12 |
| IIR-M | 2005–2009 | 8 | 0 | 0 | 0 | 7 |
| IIF | 2010– | 2 | 0 | 10 | 0 | 2 |
| IIIA | 2014– | 0 | 0 | 0 | 12 | 0 |
| IIIB | Theoretical | 0 | 0 | 0 | 8 | 0 |
| IIIC | Theoretical | 0 | 0 | 0 | 16 | 0 |
| Total | 60 | 2 | 10 | 36 | 31 | |
| (Last update: 24 May 2010) PRN 01 from Block IIR-M is unhealthy |
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- In 1972, the USAF Central Inertial Guidance Test Facility (Holloman AFB), conducted developmental flight tests of two prototype GPS receivers over White Sands Missile Range, using ground-based pseudo-satellites.[citation needed]
- In 1978, the first experimental Block-I GPS satellite was launched.
- In 1983, after Soviet interceptor aircraft shot down the civilian airliner KAL 007 that strayed into prohibited airspace because of navigational errors, killing all 269 people on board, U.S. President Ronald Reagan announced that GPS would be made available for civilian uses once it was completed.,[18][19] although it had been previously published [in Navigation magazine] that the CA code would be available to civilian users.
- By 1985, ten more experimental Block-I satellites had been launched to validate the concept. Command & Control of these satellites had moved from Onizuka AFS, CA and turned over to the 2nd Satellite Control Squadron (2SCS) located at Falcon Air Force Station in Colorado Springs, Colorado.[20][21]
- On February 14, 1989, the first modern Block-II satellite was launched.
- The Gulf War from 1990 to 1991, was the first conflict where GPS was widely used.[22]
- In 1992, the 2nd Space Wing, which originally managed the system, was de-activated and replaced by the 50th Space Wing.
- By December 1993, GPS achieved initial operational capability (IOC), indicating a full constellation (24 satellites) was available and providing the Standard Positioning Service (SPS).[23]
- Full Operational Capability (FOC) was declared by Air Force Space Command (AFSPC) in April 1995, signifying full availability of the military's secure Precise Positioning Service (PPS).[23]
- In 1996, recognizing the importance of GPS to civilian users as well as military users, U.S. President Bill Clinton issued a policy directive[24] declaring GPS to be a dual-use system and establishing an Interagency GPS Executive Board to manage it as a national asset.
- In 1998, United States Vice President Al Gore announced plans to upgrade GPS with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety and in 2000 the United States Congress authorized the effort, referring to it as GPS III.
- On May 2, 2000 "Selective Availability" was discontinued as a result of the 1996 executive order, allowing users to receive a non-degraded signal globally.
- In 2004, the United States Government signed an agreement with the European Community establishing cooperation related to GPS and Europe's planned Galileo system.
- In 2004, United States President George W. Bush updated the national policy and replaced the executive board with the National Executive Committee for Space-Based Positioning, Navigation, and Timing.[25]
- November 2004, QUALCOMM announced successful tests of assisted GPS for mobile phones.[26]
- In 2005, the first modernized GPS satellite was launched and began transmitting a second civilian signal (L2C) for enhanced user performance.
- On September 14, 2007, the aging mainframe-based Ground Segment Control System was transferred to the new Architecture Evolution Plan.[27]
- On May 19, 2009, the United States Government Accountability Office issued a report warning that some GPS satellites could fail as soon as 2010.[28]
- On May 21, 2009, the Air Force Space Command allayed fears of GPS failure saying "There's only a small risk we will not continue to exceed our performance standard."[29]
- On January 11, 2010, an update of ground control systems caused a software incompatibility with 8000 to 10000 military receivers manufactured by a division of Trimble Navigation Limited of Sunnyvale, Calif.[30]
- On February 25, 2010,[31] the U.S. Air Force awarded the contract to develop the GPS Next Generation Operational Control System (OCX) to improve accuracy and availability of GPS navigation signals, and serve as a critical part of GPS modernization.
- A GPS satellite was launched on May 28, 2010.[32] The oldest GPS satellite still in operation was launched on November 26, 1990, and became operational on December 10, 1990.[33]
- The GPS satellite, GPS IIF-2, was launched on July 16, 2011 at 06:41 GMT from Space Launch Complex 37B at the Cape Canaveral Air Force Station.[34]
Awards[link]
On February 10, 1993, the National Aeronautic Association selected the GPS Team as winners of the 1992 Robert J. Collier Trophy, the nation's most prestigious aviation award. This team combines researchers from the Naval Research Laboratory, the USAF, the Aerospace Corporation, Rockwell International Corporation, and IBM Federal Systems Company. The citation honors them "for the most significant development for safe and efficient navigation and surveillance of air and spacecraft since the introduction of radio navigation 50 years ago."
Two GPS developers received the National Academy of Engineering Charles Stark Draper Prize for 2003:
- Ivan Getting, emeritus president of The Aerospace Corporation and an engineer at the Massachusetts Institute of Technology, established the basis for GPS, improving on the World War II land-based radio system called LORAN (Long-range Radio Aid to Navigation).
- Bradford Parkinson, professor of aeronautics and astronautics at Stanford University, conceived the present satellite-based system in the early 1960s and developed it in conjunction with the U.S. Air Force. Parkinson served twenty-one years in the Air Force, from 1957 to 1978, and retired with the rank of colonel.
- GPS developer Roger L. Easton received the National Medal of Technology on February 13, 2006.[35]
In 1998, GPS technology was inducted into the Space Foundation Space Technology Hall of Fame.[36]
Francis X. Kane (Col. USAF, ret.) was inducted into the U.S. Air Force Space and Missile Pioneers Hall of Fame at Lackland A.F.B., San Antonio, Texas, March 2, 2010 for his role in space technology development and the engineering design concept of GPS conducted as part of Project 621B.
On October 4, 2011, the International Astronautical Federation (IAF) awarded the Global Positioning System (GPS) its 60th Anniversary Award, nominated by IAF member, the American Institute for Aeronautics and Astronautics (AIAA). The IAF Honors and Awards Committee recognized the uniqueness of the GPS program and the exemplary role it has played in building international collaboration for the benefit of humanity.
Basic concept of GPS[link]
A GPS receiver calculates its position by precisely timing the signals sent by GPS satellites high above the Earth. Each satellite continually transmits messages that include
- the time the message was transmitted
- satellite position at time of message transmission
The receiver uses the messages it receives to determine the transit time of each message and computes the distance to each satellite. These distances along with the satellites' locations are used with the possible aid of trilateration, depending on which algorithm is used, to compute the position of the receiver. This position is then displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units show derived information such as direction and speed, calculated from position changes.
Three satellites might seem enough to solve for position since space has three dimensions and a position near the Earth's surface can be assumed. However, even a very small clock error multiplied by the very large speed of light[37] — the speed at which satellite signals propagate — results in a large positional error. Therefore receivers use four or more satellites to solve for both the receiver's location and time. The very accurately computed time is effectively hidden by most GPS applications, which use only the location. A few specialized GPS applications do however use the time; these include time transfer, traffic signal timing, and synchronization of cell phone base stations.
Although four satellites are required for normal operation, fewer apply in special cases. If one variable is already known, a receiver can determine its position using only three satellites. For example, a ship or aircraft may have known elevation. Some GPS receivers may use additional clues or assumptions such as reusing the last known altitude, dead reckoning, inertial navigation, or including information from the vehicle computer, to give a less degraded position when fewer than four satellites are visible.[38][39][40]
Position calculation introduction[link]
To provide an introductory description of how a GPS receiver works, error effects are deferred to a later section. Using messages received from a minimum of four visible satellites, a GPS receiver is able to determine the times sent and then the satellite positions corresponding to these times sent. The x, y, and z components of position, and the time sent, are designated as Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle\left[x_i,\, y_i,\, z_i,\, t_i\right]
where the subscript i has the value 1, 2, 3, or 4. Knowing the indicated time the message was received Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle\ {t}_{r}
, the GPS receiver computes the transit time of the message as Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle\left ( {t}_r-t_i\right ) . A pseudorange, Failed to parse (Missing texvc executable; please see math/README to configure.): \scriptstyle p_i \triangleq \left ( {t}_r-t_i\right )c , is computed as an approximation of the distance from satellite to GPS receiver.
A satellite's position and pseudorange define a sphere, centered on the satellite, with radius equal to the pseudorange. The position of the receiver is somewhere on the surface of this sphere. Thus with four satellites, the indicated position of the GPS receiver is at or near the intersection of the surfaces of four spheres. In the ideal case of no errors, the GPS receiver would be at a precise intersection of the four surfaces.
If the surfaces of two spheres intersect at more than one point, they intersect in a circle. The article trilateration shows this mathematically. A figure, Two Sphere Surfaces Intersecting in a Circle, is shown below. Two points where the surfaces of the spheres intersect are clearly shown in the figure. The distance between these two points is the diameter of the circle of intersection. The intersection of a third spherical surface with the first two will be its intersection with that circle; in most cases of practical interest, this means they intersect at two points.[41] Another figure, Surface of Sphere Intersecting a Circle (not a solid disk) at Two Points, illustrates the intersection. The two intersections are marked with dots. Again the article trilateration clearly shows this mathematically.
For automobiles and other near-earth vehicles, the correct position of the GPS receiver is the intersection closest to the Earth's surface.[42] For space vehicles, the intersection farthest from Earth may be the correct one.
The correct position for the GPS receiver is also on the intersection with the surface of the sphere corresponding to the fourth satellite.
Correcting a GPS receiver's clock[link]
 |
This unreferenced section requires citations to ensure verifiability. |
One of the most significant error sources is the GPS receiver's clock. Because of the very large value of the speed of light, c, the estimated distances from the GPS receiver to the satellites, the pseudoranges, are very sensitive to errors in the GPS receiver clock; for example an error of one microsecond (0.000 001 second) corresponds to an error of 300 metres (980 ft). This suggests that an extremely accurate and expensive clock is required for the GPS receiver to work; however, manufacturers prefer to build inexpensive GPS receivers for mass markets. This dilemma is resolved by taking advantage of the fact that there are four pseudoranges.
It is likely that the surfaces of the three spheres intersect, because the circle of intersection of the first two spheres is normally quite large, and thus the third sphere surface is likely to intersect this large circle. If the clock is wrong, it is very unlikely that the surface of the sphere corresponding to the fourth satellite will initially intersect either of the two points of intersection of the first three, because any clock error could cause it to miss intersecting a point. On the other hand if a solution has been found such that all four sphere surfaces at least approximately intersect with a small deviation from a perfect intersection then it is quite likely that an accurate estimation of receiver position will have been found and that the clock is quite accurate. Methods of solution are discussed in the navigation equations section of this article.
Structure[link]
The current GPS consists of three major segments. These are the space segment (SS), a control segment (CS), and a user segment (US).[43] The U.S. Air Force develops, maintains, and operates the space and control segments. GPS satellites broadcast signals from space, and each GPS receiver uses these signals to calculate its three-dimensional location (latitude, longitude, and altitude) and the current time.[44]
The space segment is composed of 24 to 32 satellites in medium Earth orbit and also includes the payload adapters to the boosters required to launch them into orbit. The control segment is composed of a master control station, an alternate master control station, and a host of dedicated and shared ground antennas and monitor stations. The user segment is composed of hundreds of thousands of U.S. and allied military users of the secure GPS Precise Positioning Service, and tens of millions of civil, commercial, and scientific users of the Standard Positioning Service (see GPS navigation devices).
Space segment[link]
See also: GPS satellite and List of GPS satellite launches
A visual example of the GPS constellation in motion with the Earth rotating. Notice how the number of satellites in view from a given point on the Earth's surface, in this example at 45°N, changes with time.
The space segment (SS) is composed of the orbiting GPS satellites, or Space Vehicles (SV) in GPS parlance. The GPS design originally called for 24 SVs, eight each in three approximately circular orbits,[45] but this was modified to six orbital planes with four satellites each.[46] The orbits are centered on the Earth, not rotating with the Earth, but instead fixed with respect to the distant stars.[47] The six orbit planes have approximately 55° inclination (tilt relative to Earth's equator) and are separated by 60° right ascension of the ascending node (angle along the equator from a reference point to the orbit's intersection).[48] The orbital period is one-half a sidereal day, i.e. 11 hours and 58 minutes.[49] The orbits are arranged so that at least six satellites are always within line of sight from almost everywhere on Earth's surface.[50] The result of this objective is that the four satellites are not evenly spaced (90 degrees) apart within each orbit. In general terms, the angular difference between satellites in each orbit is 30, 105, 120, and 105 degrees apart which, of course, sum to 360 degrees.
Orbiting at an altitude of approximately 20,200 km (12,600 mi); orbital radius of approximately 26,600 km (16,500 mi), each SV makes two complete orbits each sidereal day, repeating the same ground track each day.[51] This was very helpful during development because even with only four satellites, correct alignment means all four are visible from one spot for a few hours each day. For military operations, the ground track repeat can be used to ensure good coverage in combat zones.
As of March 2008[update],[52] there are 31 actively broadcasting satellites in the GPS constellation, and two older, retired from active service satellites kept in the constellation as orbital spares. The additional satellites improve the precision of GPS receiver calculations by providing redundant measurements. With the increased number of satellites, the constellation was changed to a nonuniform arrangement. Such an arrangement was shown to improve reliability and availability of the system, relative to a uniform system, when multiple satellites fail.[53] About nine satellites are visible from any point on the ground at any one time (see animation at right), ensuring considerable redundancy over the minimum four satellites needed for a position.
Control segment[link]
The control segment is composed of
- a master control station (MCS),
- an alternate master control station,
- four dedicated ground antennas and
- six dedicated monitor stations
The MCS can also access U.S. Air Force Satellite Control Network (AFSCN) ground antennas (for additional command and control capability) and NGA (National Geospatial-Intelligence Agency) monitor stations. The flight paths of the satellites are tracked by dedicated U.S. Air Force monitoring stations in Hawaii, Kwajalein, Ascension Island, Diego Garcia, Colorado Springs, Colorado and Cape Canaveral, along with shared NGA monitor stations operated in England, Argentina, Ecuador, Bahrain, Australia and Washington DC.[54] The tracking information is sent to the Air Force Space Command's MCS at Schriever Air Force Base 25 km (16 mi) ESE of Colorado Springs, which is operated by the 2nd Space Operations Squadron (2 SOPS) of the U.S. Air Force. Then 2 SOPS contacts each GPS satellite regularly with a navigational update using dedicated or shared (AFSCN) ground antennas (GPS dedicated ground antennas are located at Kwajalein, Ascension Island, Diego Garcia, and Cape Canaveral). These updates synchronize the atomic clocks on board the satellites to within a few nanoseconds of each other, and adjust the ephemeris of each satellite's internal orbital model. The updates are created by a Kalman filter that uses inputs from the ground monitoring stations, space weather information, and various other inputs.[55]
Satellite maneuvers are not precise by GPS standards. So to change the orbit of a satellite, the satellite must be marked unhealthy, so receivers will not use it in their calculation. Then the maneuver can be carried out, and the resulting orbit tracked from the ground. Then the new ephemeris is uploaded and the satellite marked healthy again.
The Operation Control Segment (OCS) currently serves as the control segment of record. It provides the operational capability that supports global GPS users and keeps the GPS system operational and performing within specification.
OCS successfully replaced the legacy 1970’s-era mainframe computer at Schriever Air Force Base in September 2007. After installation, the system helped enable upgrades and provide a foundation for a new security architecture that supported the U.S. armed forces. OCS will continue to be the ground control system of record until the new segment, Next Generation GPS Operation Control System [2] (OCX), is fully developed and functional.
The new capabilities provided by OCX will be the cornerstone for revolutionizing GPS’s mission capabilities, and enabling [56] Air Force Space Command to greatly enhance GPS operational services to U.S. combat forces, civil partners and myriad of domestic and international users.
The GPS OCX program also will reduce cost, schedule and technical risk. It is designed to provide 50% [57] sustainment cost savings through efficient software architecture and Performance-Based Logistics. In addition, GPS OCX expected to cost millions less than the cost to upgrade OCS while providing four times the capability.
The GPS OCX program represents a critical part of GPS modernization and provides significant information assurance improvements over the current GPS OCS program.
- OCX will have the ability to control and manage GPS legacy satellites as well as the next generation of GPS III satellites, while enabling the full array of military signals.
- Built on a flexible architecture that can rapidly adapt to the changing needs of today’s and future GPS users allowing immediate access to GPS data and constellations status through secure, accurate and reliable information.
- Empowers the warfighter with more secure, actionable and predictive information to enhance situational awareness.
- Enables new modernized signals (L1C, L2C, and L5) and has M-code capability, which the legacy system is unable to do.
- Provides significant information assurance improvements over the current program including detecting and preventing cyber attacks, while isolating, containing and operating during such attacks.
- Supports higher volume near real-time command and control capability.
On September 14, 2011,[58] the U.S. Air Force announced the completion of GPS OCX Preliminary Design Review and confirmed that the OCX program is ready for the next phase of development.
The GPS OCX program has achieved major milestones and is on track to support the GPS IIIA launch in May 2014.
User segment[link]
The user segment is composed of hundreds of thousands of U.S. and allied military users of the secure GPS Precise Positioning Service, and tens of millions of civil, commercial and scientific users of the Standard Positioning Service. In general, GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly stable clock (often a crystal oscillator). They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously. Originally limited to four or five, this has progressively increased over the years so that, as of 2007[update], receivers typically have between 12 and 20 channels.[59]
GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of an RS-232 port at 4,800 bit/s speed. Data is actually sent at a much lower rate, which limits the accuracy of the signal sent using RTCM[citation needed]. Receivers with internal DGPS receivers can outperform those using external RTCM data[citation needed]. As of 2006[update], even low-cost units commonly include Wide Area Augmentation System (WAAS) receivers.
Many GPS receivers can relay position data to a PC or other device using the NMEA 0183 protocol. Although this protocol is officially defined by the National Marine Electronics Association (NMEA),[60] references to this protocol have been compiled from public records, allowing open source tools like gpsd to read the protocol without violating intellectual property laws. Other proprietary protocols exist as well, such as the SiRF and MTK protocols. Receivers can interface with other devices using methods including a serial connection, USB, or Bluetooth.
Further information: GPS navigation device
Applications[link]
While originally a military project, GPS is considered a dual-use technology, meaning it has significant military and civilian applications.
GPS has become a widely deployed and useful tool for commerce, scientific uses, tracking, and surveillance. GPS's accurate time facilitates everyday activities such as banking, mobile phone operations, and even the control of power grids by allowing well synchronized hand-off switching.[44]
Civilian[link]
See also: GNSS applications and GPS navigation device
Many civilian applications use one or more of GPS's three basic components: absolute location, relative movement, and time transfer.
- Clock synchronization: The accuracy of GPS time signals (±10 ns)[61] is second only to the atomic clocks upon which they are based.
- Cellular telephony: Clock synchronization enables time transfer, which is critical for synchronizing its spreading codes with other base stations to facilitate inter-cell handoff and support hybrid GPS/cellular position detection for mobile emergency calls and other applications. The first handsets with integrated GPS launched in the late 1990s. The U.S. Federal Communications Commission (FCC) mandated the feature in either the handset or in the towers (for use in triangulation) in 2002 so emergency services could locate 911 callers. Third-party software developers later gained access to GPS APIs from Nextel upon launch, followed by Sprint in 2006, and Verizon soon thereafter.
- Disaster relief/emergency services: Depend upon GPS for location and timing capabilities.
- Geofencing: Vehicle tracking systems, person tracking systems, and pet tracking systems use GPS to locate a vehicle, person, or pet. These devices are attached to the vehicle, person, or the pet collar. The application provides continuous tracking and mobile or Internet updates should the target leave a designated area.[62]
- Geotagging: Applying location coordinates to digital objects such as photographs and other documents for purposes such as creating map overlays.
- GPS Aircraft Tracking
- GPS tours: Location determines what content to display; for instance, information about an approaching point of interest.
- Map-making: Both civilian and military cartographers use GPS extensively.
- Navigation: Navigators value digitally precise velocity and orientation measurements.
- Phasor measurements: GPS enables highly accurate timestamping of power system measurements, making it possible to compute phasors.
- Robotics: Self-navigating, autonomous robots using a GPS sensors, which calculate latitude, longitude, time, speed, and heading.
- Recreation: For example, geocaching, geodashing, GPS drawing and waymarking.
- Surveying: Surveyors use absolute locations to make maps and determine property boundaries.
- Tectonics: GPS enables direct fault motion measurement in earthquakes.
- Telematics: GPS technology integrated with computers and mobile communications technology in automotive navigation systems
- Fleet Tracking: The use of GPS technology to identify, locate and maintain contact reports with one or more fleet vehicles in real-time.
Restrictions on civilian use[link]
The U.S. Government controls the export of some civilian receivers. All GPS receivers capable of functioning above 18 kilometres (11 mi) altitude and 515 metres per second (1,001 kn)[63] are classified as munitions (weapons) for which State Department export licenses are required. These limits attempt to prevent use of a receiver in a ballistic missile. They would not prevent use in a cruise missile because their altitudes and speeds are similar to those of ordinary aircraft.
This rule applies even to otherwise purely civilian units that only receive the L1 frequency and the C/A (Coarse/Acquisition) code and cannot correct for Selective Availability (SA), etc.
Disabling operation above these limits exempts the receiver from classification as a munition. Vendor interpretations differ. The rule targets operation given the combination of altitude and speed, while some receivers stop operating even when stationary. This has caused problems with some amateur radio balloon launches that regularly reach 30 kilometres (19 mi).
These limits only apply to units exported from (or which have components exported from) the USA - there is a growing trade in various components, including GPS units, supplied by other countries, which are expressly sold as ITAR-free.
Military[link]
_bombs_in_the_forward_mess_decks.jpg)
As of 2009, military applications of GPS include:
- Navigation: GPS allows soldiers to find objectives, even in the dark or in unfamiliar territory, and to coordinate troop and supply movement. In the United States armed forces, commanders use the Commanders Digital Assistant and lower ranks use the Soldier Digital Assistant.[64][65][66][67]
- Target tracking: Various military weapons systems use GPS to track potential ground and air targets before flagging them as hostile.[citation needed] These weapon systems pass target coordinates to precision-guided munitions to allow them to engage targets accurately. Military aircraft, particularly in air-to-ground roles, use GPS to find targets (for example, gun camera video from AH-1 Cobras in Iraq show GPS co-ordinates that can be viewed with specialized software).
- Missile and projectile guidance: GPS allows accurate targeting of various military weapons including ICBMs, cruise missiles and precision-guided munitions. Artillery projectiles. Embedded GPS receivers able to withstand accelerations of 12,000 g or about 118 km/s2 have been developed for use in 155 millimetres (6.1 in) howitzers.[68]
- Search and Rescue: Downed pilots can be located faster if their position is known.
- Reconnaissance: Patrol movement can be managed more closely.
- GPS satellites carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an electromagnetic pulse (EMP) sensor (W-sensor), that form a major portion of the United States Nuclear Detonation Detection System.[69][70]
Communication[link]
Main article: GPS signals
The navigational signals transmitted by GPS satellites encode a variety of information including satellite positions, the state of the internal clocks, and the health of the network. These signals are transmitted on two separate carrier frequencies that are common to all satellites in the network. Two different encodings are used: a public encoding that enables lower resolution navigation, and an encrypted encoding used by the U.S. military.
Message format[link]
-
GPS message format Subframes Description 1 Satellite clock,
GPS time relationship2–3 Ephemeris
(precise satellite orbit)4–5 Almanac component
(satellite network synopsis,
error correction)
Each GPS satellite continuously broadcasts a navigation message on L1 C/A and L2 P/Y at a rate of 50 bits per second (see bitrate). Each complete message takes 750 seconds (12 1/2 minutes) to complete. The message structure has a basic format of a 1500-bit-long frame made up of five subframes, each subframe being 300 bits (6 seconds) long. Subframes 4 and 5 are subcommutated 25 times each, so that a complete data message requires the transmission of 25 full frames. Each subframe consists of ten words, each 30 bits long. Thus, with 300 bits in a subframe times 5 subframes in a frame times 25 frames in a message, each message is 37,500 bits long. At a transmission rate of 50 bps, this gives 750 seconds to transmit an entire almanac message. Each 30-second frame begins precisely on the minute or half minute as indicated by the atomic clock on each satellite.[71]
The first part of the message encodes the week number and the time within the week,[72] as well as the data about the health of the satellite. The second part of the message, the ephemeris, provides the precise orbit for the satellite. The last part of the message, the almanac, sub commutated in subframes 4 & 5, contains coarse orbit and status information for up to 32 satellites in the constellation as well as data related to error correction. Thus, in order to obtain an accurate satellite location from this transmitted message the receiver must demodulate the message from each satellite it includes in its solution for 18 to 30 seconds. In order to collect all the transmitted almanacs the receiver must demodulate the message for 732 to 750 seconds or 12 1/2 minutes.[73]
All satellites broadcast at the same frequencies. Signals are encoded using code division multiple access (CDMA) allowing messages from individual satellites to be distinguished from each other based on unique encodings for each satellite (that the receiver must be aware of). Two distinct types of CDMA encodings are used: the coarse/acquisition (C/A) code, which is accessible by the general public, and the precise (P) code, that is encrypted so that only the U.S. military can access it.
The ephemeris is updated every 2 hours and is generally valid for 4 hours, with provisions for updates every 6 hours or longer in non-nominal conditions. The almanac is updated typically every 24 hours. Additionally data for a few weeks following is uploaded in case of transmission updates that delay data upload.
Satellite frequencies[link]
-
GPS frequency overview Band Frequency Description L1 1575.42 MHz Coarse-acquisition (C/A) and encrypted precision P(Y) codes, plus the L1 civilian (L1C) and military (M) codes on future Block III satellites. L2 1227.60 MHz P(Y) code, plus the L2C and military codes on the Block IIR-M and newer satellites. L3 1381.05 MHz Used for nuclear detonation (NUDET) detection. L4 1379.913 MHz Being studied for additional ionospheric correction.[citation needed] L5 1176.45 MHz Proposed for use as a civilian safety-of-life (SoL) signal.
All satellites broadcast at the same two frequencies, 1.57542 GHz (L1 signal) and 1.2276 GHz (L2 signal). The satellite network uses a CDMA spread-spectrum technique where the low-bitrate message data is encoded with a high-rate pseudo-random (PRN) sequence that is different for each satellite. The receiver must be aware of the PRN codes for each satellite to reconstruct the actual message data. The C/A code, for civilian use, transmits data at 1.023 million chips per second, whereas the P code, for U.S. military use, transmits at 10.23 million chips per second. The actual internal reference of the satellites is 10.22999999543MHz to compensate for relativistic effects[74] [75] that make observers on Earth perceive a different time reference with respect to the transmitters in orbit.
The L1 carrier is modulated by both the C/A and P codes, while the L2 carrier is only modulated by the P code.[76] The P code can be encrypted as a so-called P(Y) code that is only available to military equipment with a proper decryption key. Both the C/A and P(Y) codes impart the precise time-of-day to the user.
The L3 signal at a frequency of 1.38105 GHz is used by the United States Nuclear Detonation (NUDET) Detection System (USNDS) to detect, locate, and report nuclear detonations (NUDETs) in the Earth's atmosphere and near space.[77] One usage is the enforcement of nuclear test ban treaties.
The L4 band at 1.379913 GHz is being studied for additional ionospheric correction.[citation needed]
The L5 frequency band at 1.17645 GHz was added in the process of GPS modernization. This frequency falls into an internationally protected range for aeronautical navigation, promising little or no interference under all circumstances. The first Block IIF satellite that would provide this signal is set to be launched in 2009.[78] The L5 consists of two carrier components that are in phase quadrature with each other. Each carrier component is bi-phase shift key (BPSK) modulated by a separate bit train. "L5, the third civil GPS signal, will eventually support safety-of-life applications for aviation and provide improved availability and accuracy." [79]
A conditional waiver has recently been granted to LightSquared to operate a terrestrial broadband service near the L1 band. Although LightSquared had applied for a license to operate in the 1525 to 1559 band as early as 2003 and it was put out for public comment, the FCC asked LightSquared to form a study group with the GPS community to test GPS receivers and identify issue that might arise due to the larger signal power from the LightSquared terrestrial network. The GPS community had not objected to the LightSquared (formerly MSV and SkyTerra) applications until November 2010, when LightSquared applied for a modification to its Ancillary Terrestrial Component (ATC) authorization. This filing (SAT-MOD-20101118-00239) amounted to a request to run several orders of magnitude more power in the same frequency band for terrestrial base stations, essentially repurposing what was supposed to be a "quiet neighborhood" for signals from space as the equivalent of a cellular network. Testing in the first half of 2011 has demonstrated that the impact of the lower 10 MHz of spectrum is minimal to GPS devices (less than 1% of the total GPS devices are affected). The upper 10 MHz intended for use by LightSquared may have some impact on GPS devices. There is some concern that this will seriously degrade the GPS signal for many consumer uses.[80][81] Aviation Week magazine reports that the latest testing (June 2011) confirms "significant jamming" of GPS by LightSquared's system.[82]
Demodulation and decoding[link]
Because all of the satellite signals are modulated onto the same L1 carrier frequency, the signals must be separated after demodulation. This is done by assigning each satellite a unique binary sequence known as a Gold code. The signals are decoded after demodulation using addition of the Gold codes corresponding to the satellites monitored by the receiver.[83][84]
If the almanac information has previously been acquired, the receiver picks the satellites to listen for by their PRNs, unique numbers in the range 1 through 32. If the almanac information is not in memory, the receiver enters a search mode until a lock is obtained on one of the satellites. To obtain a lock, it is necessary that there be an unobstructed line of sight from the receiver to the satellite. The receiver can then acquire the almanac and determine the satellites it should listen for. As it detects each satellite's signal, it identifies it by its distinct C/A code pattern. There can be a delay of up to 30 seconds before the first estimate of position because of the need to read the ephemeris data.
Processing of the navigation message enables the determination of the time of transmission and the satellite position at this time. For more information see Demodulation and Decoding, Advanced.
Navigation equations[link]
The receiver uses messages received from satellites to determine the satellite positions and time sent. The x, y, and z components of satellite position and the time sent are designated as [xi, yi, zi, ti] where the subscript i denotes the satellite and has the value 1, 2, ..., n, where Failed to parse (Missing texvc executable; please see math/README to configure.): n \ge 4.
When the time of message reception indicated by the on-board clock is Failed to parse (Missing texvc executable; please see math/README to configure.): \, t_\text{r}
, the message's transit time is Failed to parse (Missing texvc executable; please see math/README to configure.): \, t_\text{r} + b - t_i
where Failed to parse (Missing texvc executable; please see math/README to configure.): \, b is clock bias. Assuming the message traveled at the speed of light (c) the distance traveled is (tr + b − ti)c. Knowing the distance from receiver to satellite and the satellite's position implies that the receiver is on the surface of a sphere centered at the satellite's position. Thus the receiver is at or near the intersection of the surfaces of the spheres. In the ideal case of no errors, the receiver is at the intersection of the surfaces of the spheres.
The clock error or bias, b , is the amount that the receiver's clock is off. The receiver has four unknowns, the three components of GPS receiver position and the clock bias [x, y, z, b]. The equations of the sphere surfaces are given by:
- Failed to parse (Missing texvc executable; please see math/README to configure.): (x-x_i)^2 + (y-y_i)^2 + (z-z_i)^2 = \bigl([ t_\text{r} + b - t_i]c\bigr)^2, \; i=1,2,\dots,n
or in terms of pseudoranges, Failed to parse (Missing texvc executable; please see math/README to configure.): p_i = \left ( t_\text{r} - t_i \right )c , as
- Failed to parse (Missing texvc executable; please see math/README to configure.): p_i = \sqrt{(x-x_i)^2 + (y-y_i)^2 + (z-z_i)^2}- bc, \;i=1,2,...,n
.
These equations can be solved by algebraic or numerical methods.
Bancroft's method[link]
Bancroft's method involves an algebraic as opposed to numerical method and can be used for the case of four satellites or for the case of more than four satellites.[85][86] If there are four satellites then Bancroft's method provides one or two solutions for the four unknowns. If there are more than four satellites then Bancroft's method provides the solution which minimizes the sum of the squares of the errors for the over determined system.
Trilateration[link]
The receiver can use trilateration [87][88] and one dimensional numerical root finding.[89] Satellite position and pseudorange determines a sphere centered on the satellite with radius equal to the pseudorange. Trilateration is used to estimate receiver position based on the intersection of three sphere surfaces so determined. In the usual case of two intersections of three sphere surfaces, the point nearest the surface of the sphere corresponding to the fourth satellite is chosen. Let d denote the signed distance from the current estimate of receiver position to the sphere around the fourth satellite. The notation, d(correction) denotes this as a function of the clock correction. The problem is to determine the correction such that d(correction) = 0. This is the familiar problem of finding the zeroes of a one dimensional non-linear function of a scalar variable. Iterative numerical methods, such as those found in the chapter on root finding in Numerical Recipes can solve this type of problem.[89]
Multidimensional Newton-Raphson calculations[link]
Alternatively, multidimensional root finding method such as Newton-Raphson method can be used.[89] The approach is to linearize around an approximate solution, say Failed to parse (Missing texvc executable; please see math/README to configure.): \ \left [x^{(k)}, y ^{(k)}, z^{(k)}, b^{(k)}\right ]
from iteration k, then solve the linear equations derived from the quadratic equations above to obtain Failed to parse (Missing texvc executable; please see math/README to configure.): \left [x^{(k+1)}, y^{(k+1)}, z^{(k+1)}, b^{(k+1)}\right ]
. Although there is no guarantee that the method always converges due to the fact that multidimensional roots cannot be bounded, when a neighborhood containing a solution is known as is usually the case for GPS, it is quite likely that a solution will be found.[89] It has been shown[90] that results are comparable in accuracy to those of the Bancroft's method.
Additional methods for more than four satellites[link]
When more than four satellites are available, the calculation can use the four best or more than four, considering number of channels, processing capability, and geometric dilution of precision (GDOP). Using more than four is an over-determined system of equations with no unique solution, which must be solved by least-squares or a similar technique.[86] If all visible satellites are used, the results are as good as or better than using the four best. Errors can be estimated through the residuals. With each combination of four or more satellites, a GDOP factor can be calculated, based on the relative sky directions of the satellites used.[91] As more satellites are picked up, pseudoranges from various 4-way combinations can be processed to add more estimates to the location and clock offset. The receiver then takes the weighted average of these positions and clock offsets. After the final location and time are calculated, the location is expressed in a specific coordinate system such as latitude and longitude, using the WGS 84 geodetic datum or a country-specific system.[92]
Error sources and analysis[link]
GPS error analysis which is found in Error analysis for the Global Positioning System is an important aspect for determining what errors and their magnitude are to be expected. GPS errors are affected by geometric dilution of precision and depend on signal arrival time errors, numerical errors, atmospherics effects, ephemeris errors, multipath errors and other effects. Variability in solar radiation pressure[93] has an indirect effect on GPS accuracy due to its effect on ephemeris errors.
Accuracy enhancement and surveying[link]
Main article: GPS augmentation
Augmentation[link]
Integrating external information into the calculation process can materially improve accuracy. Such augmentation systems are generally named or described based on how the information arrives. Some systems transmit additional error information (such as clock drift, ephemera, or ionospheric delay), others characterize prior errors, while a third group provides additional navigational or vehicle information.
Examples of augmentation systems include the Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), Differential GPS, Inertial Navigation Systems (INS) and Assisted GPS.
Precise monitoring[link]
Accuracy can be improved through precise monitoring and measurement of existing GPS signals in additional or alternate ways.
The largest remaining error is usually the unpredictable delay through the ionosphere. The spacecraft broadcast ionospheric model parameters, but errors remain. This is one reason GPS spacecraft transmit on at least two frequencies, L1 and L2. Ionospheric delay is a well-defined function of frequency and the total electron content (TEC) along the path, so measuring the arrival time difference between the frequencies determines TEC and thus the precise ionospheric delay at each frequency.
Military receivers can decode the P(Y)-code transmitted on both L1 and L2. Without decryption keys, it is still possible to use a codeless technique to compare the P(Y) codes on L1 and L2 to gain much of the same error information. However, this technique is slow, so it is currently available only on specialized surveying equipment. In the future, additional civilian codes are expected to be transmitted on the L2 and L5 frequencies (see GPS modernization). Then all users will be able to perform dual-frequency measurements and directly compute ionospheric delay errors.
A second form of precise monitoring is called Carrier-Phase Enhancement (CPGPS). This corrects the error that arises because the pulse transition of the PRN is not instantaneous, and thus the correlation (satellite-receiver sequence matching) operation is imperfect. CPGPS uses the L1 carrier wave, which has a period of Failed to parse (Missing texvc executable; please see math/README to configure.): \frac{1\,\mathrm{s}}{1575.42 \times 10^6} = 0.63475\,\mathrm{ns} \approx 1\, \mathrm{ns} \ , which is about one-thousandth of the C/A Gold code bit period of Failed to parse (Missing texvc executable; please see math/README to configure.): \frac{1\, \mathrm{s}}{1023 \times 10^3} = 977.5 \, \mathrm{ns} \approx 1000 \, \mathrm{ns} \ , to act as an additional clock signal and resolve the uncertainty. The phase difference error in the normal GPS amounts to 2–3 metres (6.6–9.8 ft) of ambiguity. CPGPS working to within 1% of perfect transition reduces this error to 3 centimetres (1.2 in) of ambiguity. By eliminating this error source, CPGPS coupled with DGPS normally realizes between 20–30 centimetres (7.9–12 in) of absolute accuracy.
Relative Kinematic Positioning (RKP) is a third alternative for a precise GPS-based positioning system. In this approach, determination of range signal can be resolved to a precision of less than 10 centimetres (3.9 in). This is done by resolving the number of cycles that the signal is transmitted and received by the receiver by using a combination of differential GPS (DGPS) correction data, transmitting GPS signal phase information and ambiguity resolution techniques via statistical tests—possibly with processing in real-time (real-time kinematic positioning, RTK).
[edit] Timekeeping
Timekeeping and leap seconds[link]
While most clocks are synchronized to Coordinated Universal Time (UTC), the atomic clocks on the satellites are set to GPS time (GPST; see the page of United States Naval Observatory). The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections that are periodically added to UTC. GPS time was set to match Coordinated Universal Time (UTC) in 1980, but has since diverged. The lack of corrections means that GPS time remains at a constant offset with International Atomic Time (TAI) (TAI – GPS = 19 seconds). Periodic corrections are performed on the on-board clocks to keep them synchronized with ground clocks.[94]
The GPS navigation message includes the difference between GPS time and UTC. As of 2011, GPS time is 15 seconds ahead of UTC because of the leap second added to UTC December 31, 2008. Receivers subtract this offset from GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) that, given the current period of the Earth's rotation (with one leap second introduced approximately every 18 months), should be sufficient to last until approximately the year 2300.
Timekeeping accuracy[link]
GPS time is accurate to about 14 nanoseconds.[95]
Timekeeping format[link]
As opposed to the year, month, and day format of the Gregorian calendar, the GPS date is expressed as a week number and a seconds-into-week number. The week number is transmitted as a ten-bit field in the C/A and P(Y) navigation messages, and so it becomes zero again every 1,024 weeks (19.6 years). GPS week zero started at 00:00:00 UTC (00:00:19 TAI) on January 6, 1980, and the week number became zero again for the first time at 23:59:47 UTC on August 21, 1999 (00:00:19 TAI on August 22, 1999). To determine the current Gregorian date, a GPS receiver must be provided with the approximate date (to within 3,584 days) to correctly translate the GPS date signal. To address this concern the modernized GPS navigation message uses a 13-bit field that only repeats every 8,192 weeks (157 years), thus lasting until the year 2137 (157 years after GPS week zero).
Carrier phase tracking (surveying)[link]
Another method that is used in surveying applications is carrier phase tracking. The period of the carrier frequency multiplied by the speed of light gives the wavelength, which is about 0.19 meters for the L1 carrier. Accuracy within 1% of wavelength in detecting the leading edge reduces this component of pseudorange error to as little as 2 millimeters. This compares to 3 meters for the C/A code and 0.3 meters for the P code.
However, 2 millimeter accuracy requires measuring the total phase—the number of waves multiplied by the wavelength plus the fractional wavelength, which requires specially equipped receivers. This method has many surveying applications.
Triple differencing followed by numerical root finding, and a mathematical technique called least squares can estimate the position of one receiver given the position of another. First, compute the difference between satellites, then between receivers, and finally between epochs. Other orders of taking differences are equally valid. Detailed discussion of the errors is omitted.
The satellite carrier total phase can be measured with ambiguity as to the number of cycles. Let Failed to parse (Missing texvc executable; please see math/README to configure.): \ \phi(r_i, s_j, t_k)
denote the phase of the carrier of satellite j measured by receiver i at time Failed to parse (Missing texvc executable; please see math/README to configure.): \ \ t_k
. This notation shows the meaning of the subscripts i, j, and k. The receiver (r), satellite (s), and time (t) come in alphabetical order as arguments of Failed to parse (Missing texvc executable; please see math/README to configure.): \ \phi
and to balance readability and conciseness, let Failed to parse (Missing texvc executable; please see math/README to configure.): \ \phi_{i,j,k} = \phi(r_i, s_j, t_k)
be a concise abbreviation. Also we define three functions, :Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^r, \Delta^s, \Delta^t
, which return differences between receivers, satellites, and time points, respectively. Each function has variables with three subscripts as its arguments. These three functions are defined below. If Failed to parse (Missing texvc executable; please see math/README to configure.): \ \alpha_{i,j,k}
is a function of the three integer arguments, i, j, and k then it is a valid argument for the functions, :Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^r, \Delta^s, \Delta^t
, with the values defined as
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^r(\alpha_{i,j,k}) = \alpha_{i+1,j,k} - \alpha_{i,j,k}
,
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^s(\alpha_{i,j,k}) = \alpha_{i,j+1,k} - \alpha_{i,j,k}
, and
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^t(\alpha_{i,j,k}) = \alpha_{i,j,k+1} - \alpha_{i,j,k}
.
Also if Failed to parse (Missing texvc executable; please see math/README to configure.): \ \alpha_{i,j,k}\ and\ \beta_{l,m,n}
are valid arguments for the three functions and a and b are constants then
Failed to parse (Missing texvc executable; please see math/README to configure.): \ ( a\ \alpha_{i,j,k} + b\ \beta_{l,m,n} )
is a valid argument with values defined as
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^r(a\ \alpha_{i,j,k} + b\ \beta_{l,m,n}) = a \ \Delta^r(\alpha_{i,j,k}) + b \ \Delta^r(\beta_{l,m,n})
,
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^s(a\ \alpha_{i,j,k} + b\ \beta_{l,m,n} )= a \ \Delta^s(\alpha_{i,j,k}) + b \ \Delta^s(\beta_{l,m,n})
, and
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^t(a\ \alpha_{i,j,k} + b\ \beta_{l,m,n} )= a \ \Delta^t(\alpha_{i,j,k}) + b \ \Delta^t(\beta_{l,m,n})
.
Receiver clock errors can be approximately eliminated by differencing the phases measured from satellite 1 with that from satellite 2 at the same epoch.[96] This difference is designated as Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^s(\phi_{1,1,1}) = \phi_{1,2,1} - \phi_{1,1,1}
Double differencing[97] computes the difference of receiver 1's satellite difference from that of receiver 2. This approximately eliminates satellite clock errors. This double difference is:
- Failed to parse (Missing texvc executable; please see math/README to configure.): \begin{align} \Delta^r(\Delta^s(\phi_{1,1,1}))\,&=\,\Delta^r(\phi_{1,2,1} - \phi_{1,1,1}) &=\,\Delta^r(\phi_{1,2,1}) - \Delta^r(\phi_{1,1,1}) &=\,(\phi_{2,2,1} - \phi_{1,2,1}) - (\phi_{2,1,1} - \phi_{1,1,1}) \end{align}
Triple differencing[98] subtracts the receiver difference from time 1 from that of time 2. This eliminates the ambiguity associated with the integral number of wave lengths in carrier phase provided this ambiguity does not change with time. Thus the triple difference result eliminates practically all clock bias errors and the integer ambiguity. Atmospheric delay and satellite ephemeris errors have been significantly reduced. This triple difference is:
- Failed to parse (Missing texvc executable; please see math/README to configure.): \ \Delta^t(\Delta^r(\Delta^s(\phi_{1,1,1})))
Triple difference results can be used to estimate unknown variables. For example if the position of receiver 1 is known but the position of receiver 2 unknown, it may be possible to estimate the position of receiver 2 using numerical root finding and least squares. Triple difference results for three independent time pairs quite possibly will be sufficient to solve for receiver 2's three position components. This may require the use of a numerical procedure.[99][100] An approximation of receiver 2's position is required to use such a numerical method. This initial value can probably be provided from the navigation message and the intersection of sphere surfaces. Such a reasonable estimate can be key to successful multidimensional root finding. Iterating from three time pairs and a fairly good initial value produces one observed triple difference result for receiver 2's position. Processing additional time pairs can improve accuracy, overdetermining the answer with multiple solutions. Least squares can estimate an overdetermined system. Least squares determines the position of receiver 2 which best fits the observed triple difference results for receiver 2 positions under the criterion of minimizing the sum of the squares.
Regulatory spectrum issues concerning GPS receivers[link]
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The neutrality of this section is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (October 2011) |
In the United States, GPS receivers are regulated under the Federal Communications Commission's (FCC) Part 15 rules. As indicated in the manuals of GPS-enabled devices sold in the United States, as a Part 15 device, it "must accept any interference received, including interference that may cause undesired operation."[101] With respect to GPS devices in particular, the FCC states that GPS receiver manufacturers, "must use receivers that reasonably discriminate against reception of signals outside their allocated spectrum."[102]
The spectrum allocated for GPS L1 use by the FCC is 1559 to 1610 MHz.[103] Since 1996, the FCC has authorized licensed use of the spectrum neighboring the GPS band of 1525 to 1559 MHz to the Virginia company LightSquared. On March 1, 2001, the FCC received an application from LightSquared's predecessor, Motient Services to use their allocated frequencies for an integrated satellite-terrestrial service.[104] In 2002, the U.S. GPS Industry Council came to an out-of-band-emissions (OOBE) agreement with LightSquared to prevent transmissions from LightSquared's ground-based stations from emitting transmissions into the neighboring GPS band of 1559 to 1610 MHz.[105] In 2004, the FCC adopted the OOBE agreement in its authorization for LightSquared to deploy a ground-based network that used its allocated frequencies of 1525 to 1559 MHz.[106] This authorization was reviewed and approved by the U.S. Interdepartment Radio Advisory Committee, which includes the U.S. Departments of Agriculture, Air Force, Army, Coast Guard, Federal Aviation Administration, National Aeronautics and Space Administration, Interior, and Transportation.[107]
In January 2011, the FCC conditionally authorized LightSquared's wholesale customers, such as Best Buy, Sharp, and C Spire, to be able to only purchase an integrated satellite-ground-based service from LightSquared and re-sell that integrated service on devices that are equipped to only use the ground-based signal using LightSquared's allocated frequencies of 1525 to 1559 MHz.[108] In December 2010, GPS receiver manufacturers expressed concerns to the FCC that LightSquared's signal would interfere with GPS receiver devices[109] although the FCC's policy considerations leading up to the January 2011 order did not pertain to any proposed changes to the maximum number of ground-based LightSquared stations or the maximum power at which these stations could operate. The January 2011 order makes final authorization contingent upon studies of GPS interference issues carried out by a LightSquared led working group along with GPS industry and Federal agency participation.
GPS receiver manufacturers design GPS receivers to use spectrum beyond the GPS-allocated band. In some cases, GPS receivers are designed to use up to 400 MHz of spectrum in either direction of the L1 frequency of 1575.42 MHz.[110] However, as regulated under the FCC's Part 15 rules, GPS receivers are not warranted protection from signals outside GPS-allocated spectrum.[102]
The FCC adopted rules in February 2003 that allowed Mobile Satellite Service (MSS) licensees such as LightSquared to construct ground-based towers in their licensed spectrum to "promote more efficient use of terrestrial wireless spectrum."[111] In July 2010, the FCC stated that it expected LightSquared to use its authority to offer an integrated satellite-terrestrial service to "provide mobile broadband services similar to those provided by terrestrial mobile providers and enhance competition in the mobile broadband sector."[112] However, GPS receiver manufacturers have argued that LightSquared's licensed spectrum of 1525 to 1559 MHz was never envisioned as being used for high-speed wireless broadband although there is no regulatory or legal backing of this claim.[113] To build public support of efforts to reverse the 2004 FCC authorization of LightSquared's network, GPS receiver manufacturer Trimble Navigation Ltd. formed the "Coalition To Save Our GPS."[114]
The FCC and LightSquared have each made public commitments to solve the GPS interference issue before the network is allowed to operate.[115][116] However, according to Chris Dancy of the Aircraft Owners and Pilots Association, airline pilots with the type of systems that would be affected "may go off course and not even realize it."[117] The problems could also affect the Federal Aviation Administration upgrade to the air traffic control system, United States Defense Department guidance, and local emergency services including 911.[117]
On February 14, 2012, the U.S. Federal Communications Commission (FCC) moved to bar LightSquared's planned national broadband network after being informed by the National Telecommunications and Information Administration (NTIA), "the federal agency that coordinates spectrum uses for the military and other federal government entities," that "there is no practical way to mitigate potential interference at this time."[118][119] LightSquared is challenging the FCC's action.
Other systems[link]
Other satellite navigation systems in use or various states of development include:
- GLONASS – Russia's global navigation system. Fully operational worldwide.
- Galileo – a global system being developed by the European Union and other partner countries, planned to be operational by 2014
- Beidou – People's Republic of China's regional system, currently limited to Asia and the West Pacific[121]
- COMPASS – People's Republic of China's global system, planned to be operational by 2020[122][123]
- IRNSS – India's regional navigation system, planned to be operational by 2012, covering India and Northern Indian Ocean[124]
- QZSS – Japanese regional system covering Asia and Oceania
See also[link]
- GPS/INS
- GPS navigation software
- High Sensitivity GPS
- Local positioning system
- Military invention
- Mobile phone tracking
- Navigation paradox
- S-GPS
References[link]
- ^ National Research Council (U.S.). Committee on the Future of the Global Positioning System; National Academy of Public Administration (1995). The global positioning system: a shared national asset: recommendations for technical improvements and enhancements. National Academies Press. p. 16. ISBN 0-309-05283-1. http://books.google.com/books?id=FAHk65slfY4C. , Chapter 1, p. 16
- ^ a b "Factsheets : GPS Advanced Control Segment (OCX)". Losangeles.af.mil. 2011-10-25. http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=18676. Retrieved 2011-11-06.
- ^ Astronautica Acta II, 25 (1956)
- ^ "GPS and Relativity". Astronomy.ohio-state.edu. http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html. Retrieved 2011-11-06.
- ^ Guier, William H.; Weiffenbach, George C. (1997). "Genesis of Satellite Navigation". John Hopkins APL Technical Digest 19 (1): pp. 178–181. http://www.jhuapl.edu/techdigest/td/td1901/guier.pdf.
- ^ Steven Johnson (2010), Where good ideas come from, the natural history of innovation, New York: Riverhead Books
- ^ Jerry Proc. "Omega". Jproc.ca. http://www.jproc.ca/hyperbolic/omega.html. Retrieved 2009-12-08.
- ^ "Why Did the Department of Defense Develop GPS?". Trimble Navigation Ltd. Archived from the original on 2007-10-18. http://web.archive.org/web/20071018151253/http://www.trimble.com/gps/whygps.shtml#0. Retrieved 2010-01-13.
- ^ "Charting a Course Toward Global Navigation". The Aerospace Corporation. http://www.aero.org/publications/crosslink/summer2002/01.html. Retrieved 2010-01-14.
- ^ "A Guide To The Global Positioning System (GPS) — GPS Timeline". Radio Shack. http://support.radioshack.com/support_tutorials/gps/gps_tmline.htm. Retrieved 2010-01-14.
- ^ Michael Russell Rip, James M. Hasik (2002). The Precision Revolution: GPS and the Future of Aerial Warfare. Naval Institute Press. p. 65. ISBN 1-55750-973-5. http://books.google.com/?id=mB9W3H90KDUC. Retrieved 2010-01-14.
- ^ "ICAO Completes Fact-Finding Investigation". International Civil Aviation Organization. http://www.icao.int/cgi/goto_m.pl?icao/en/trivia/kal_flight_007.htm. Retrieved 2008-09-15.
- ^ "United States Updates Global Positioning System Technology". America.gov. February 3, 2006. http://www.america.gov/xarchives/display.html?p=washfile-english&y=2006&m=February&x=20060203125928lcnirellep0.5061609.
- ^ "GPS & Selective Availability Q&A". [1]. http://ngs.woc.noaa.gov/FGCS/info/sans_SA/docs/GPS_SA_Event_QAs.pdf. Retrieved 2010-05-28.
- ^ "GPS Modernization Fact Sheet". U.S. Air Force. http://www.pnt.gov/public/docs/2006/modernization.pdf.
- ^ GPS Wing Reaches GPS III IBR Milestone in InsideGNSS November 10, 2008
- ^ "GPS almanacs". Navcen.uscg.gov. http://www.navcen.uscg.gov/?pageName=gpsAlmanacs. Retrieved 2010-10-15.
- ^ Dietrich Schroeer, Mirco Elena (2000). Technology Transfer. Ashgate. p. 80. ISBN 0-7546-2045-X. http://books.google.com/?id=I7JRAAAAMAAJ. Retrieved 2008-05-25.
- ^ Michael Russell Rip, James M. Hasik (2002). The Precision Revolution: GPS and the Future of Aerial Warfare. Naval Institute Press. ISBN 1-55750-973-5. http://books.google.com/?id=_wpUAAAAMAAJ. Retrieved 2008-05-25.
- ^ "AF Space Command Chronology". USAF Space Command. http://www.afspc.af.mil/heritage/chronology.asp. Retrieved 20 June 2011.
- ^ "FactSheet: 2nd Space Operations Squadron". USAF Space Command. http://www.schriever.af.mil/library/factsheets/factsheet.asp?id=4045. Retrieved 20 June 2011.
- ^ The Global Positioning System: Assessing National Policies, p.245. RAND corporation
- ^ a b "USNO NAVSTAR Global Positioning System". U.S. Naval Observatory. http://tycho.usno.navy.mil/gpsinfo.html. Retrieved 2011-01-07.
- ^ National Archives and Records Administration. U.S. Global Positioning System Policy. March 29, 1996.
- ^ "National Executive Committee for Space-Based Positioning, Navigation, and Timing". Pnt.gov. http://pnt.gov/. Retrieved 2010-10-15.
- ^ "Assisted-GPS Test Calls for 3G WCDMA Networks". 3g.co.uk. November 10, 2004. http://www.3g.co.uk/PR/November2004/8641.htm. Retrieved 2010-11-24.
- ^ This story was written by 010907 (2007-09-17). "losangeles.af.mil". losangeles.af.mil. http://www.losangeles.af.mil/news/story.asp?id=123068412. Retrieved 2010-10-15.
- ^ Johnson, Bobbie (May 19, 2009). "GPS system 'close to breakdown'". The Guardian (London). http://www.guardian.co.uk/technology/2009/may/19/gps-close-to-breakdown. Retrieved 2009-12-08.
- ^ Coursey, David (May 21, 2009). "Air Force Responds to GPS Outage Concerns". ABC News. http://abcnews.go.com/Technology/AheadoftheCurve/story?id=7647002&page=1. Retrieved 2009-05-22.
- ^ "Air Force GPS Problem: Glitch Shows How Much U.S. Military Relies On GPS". Huffingtonpost.comm. 2010-06-01. http://www.huffingtonpost.com/2010/06/01/air-force-gps-problem-gli_n_595727.html. Retrieved 2010-10-15.
- ^ "Raytheon Awarded Next-Generation Control Segment Contract (OCX)". http://www.gpsworld.com/gnss-system/gps-modernization/news/raytheon-awarded-next-generation-control-segment-contract-ocx-960. Retrieved 2010-02-25.
- ^ "United States Naval Observatory (USNO) GPS Constellation Status". ftp://tycho.usno.navy.mil/pub/gps/gpstd.txt. Retrieved 2009-10-13.
- ^ United States Naval Observatory. GPS Constellation Status. Retrieved December 20, 2008.
- ^ "United Launch Alliance GPS IIF-2". United Launch Alliance. http://www.ulalaunch.com/site/pages/News.shtml#/73/. Retrieved 16 July 2011.
- ^ United States Naval Research Laboratory. National Medal of Technology for GPS. November 21, 2005
- ^ "Space Technology Hall of Fame, Inducted Technology: Global Positioning System (GPS)". http://www.spacetechhalloffame.org/inductees_1998_Global_Positioning_System.html.
- ^ GPS signals travel at the speed of light, so computing the distance for a given elapsed time is almost a straightforward calculation. However, the speed of light varies slightly between the partial vacuum of space and the atmosphere. A receiver can approximate these effects and produce a reasonable estimate. Once a rough position is determined, some receivers carefully compute the amount of atmosphere the signal traveled through and adjust the distance accordingly.
- ^ Georg zur Bonsen, Daniel Ammann, Michael Ammann, Etienne Favey, Pascal Flammant (2005-04-01). "Continuous Navigation Combining GPS with Sensor-Based Dead Reckoning". GPS World. Archived from the original on 2006-11-11. http://web.archive.org/web/20061111202317/http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=154870&pageID=6.
- ^ "NAVSTAR GPS User Equipment Introduction" (PDF). United States Government. http://www.navcen.uscg.gov/pubs/gps/gpsuser/gpsuser.pdf. Chapter 7
- ^ "GPS Support Notes" (PDF). 19 January 2007. Archived from the original on 27 March 2009. http://web.archive.org/web/20090327051208/http://www.navmanwireless.com/uploads/EK/C8/EKC8zb1ITsNwDqWcqLQxiQ/Support_Notes_GPS_OperatingParameters.pdf. Retrieved 10 November 2008.
- ^ It is also possible for a circle and a spherical surface to intersect at zero points, one point, or in the very special case where the centers of the three spheres are co-linear (i.e., all three on the same straight line) the sphere surface could intersect the entire circumference of the circle.
- ^ The two intersections are symmetrical about the plane containing the three satellites. Excluding the exceptional case when the three satellites are all in a plane containing the center of the earth, one intersection will be nearer the earth than the other.
- ^ John Pike. "GPS III Operational Control Segment (OCX)". Globalsecurity.org. http://www.globalsecurity.org/space/systems/gps_3-ocx.htm. Retrieved 2009-12-08.
- ^ a b "Global Positioning System". Gps.gov. http://www.gps.gov/systems/gps/index.html. Retrieved 2010-06-26.
- ^ Daly, P.. "Navstar GPS and GLONASS: global satellite navigation systems". IEEE. http://ieeexplore.ieee.org/iel1/2219/7072/00285510.pdf?arnumber=285510.
- ^ Dana, Peter H. (1996-08-08). "GPS Orbital Planes" (GIF). http://www.colorado.edu/geography/gcraft/notes/gps/gif/oplanes.gif.
- ^ What the Global Positioning System Tells Us about Relativity. Retrieved January 2, 2007.
- ^ GPS Overview from the NAVSTAR Joint Program Office. Retrieved December 15, 2006.
- ^ [2] Retrieved October 27, 2011
- ^ "USCG Navcen: GPS Frequently Asked Questions". http://www.navcen.uscg.gov/?pageName=gpsFaq. Retrieved 2007-01-31.
- ^ Agnew, D.C. and Larson, K.M. (2007). "Finding the repeat times of the GPS constellation". GPS Solutions (Springer) 11 (1): 71–76. DOI:10.1007/s10291-006-0038-4. This article from author's web site, with minor correction.
- ^ Tis-pf-nisws. "Nanu 2008030". http://cgls.uscg.mil/pipermail/gps/2008-March/001625.html.
- ^ Massatt, Paul; Wayne Brady (Summer 2002). "Optimizing performance through constellation management". Crosslink: 17–21. http://www.aero.org/publications/crosslink/summer2002/index.html.
- ^ United States Coast Guard General GPS News 9–9–05
- ^ USNO NAVSTAR Global Positioning System. Retrieved May 14, 2006.
- ^ "GPS III Operational Control Segment (OCX)". GlobalSecurity.org. http://www.globalsecurity.org/space/systems/gps_3-ocx.htm.
- ^ "The USA’s GPS-III Satellites". Defense Industry Daily. 2011-10-13. http://www.defenseindustrydaily.com/The-USAs-GPS-III-Satellites-04900/.
- ^ "GPS Completes Next Generation Operational Control System PDR". Air Force Space Command News Service. 2011-09-14. http://www.comspacewatch.com/news/viewpr.html?pid=34625.
- ^ Though there are many receiver manufacturers, they almost all use one of the chipsets produced for this purpose. An example: "GPS Receiver Chip Performance Survey". GPS Technology Reviews. http://gpstekreviews.com/2007/04/14/gps-receiver-chip-performance-survey/.
- ^ "Publications and Standards from the National Marine Electronics Association (NMEA)". National Marine Electronics Association. http://www.nmea.org/pub/index.html. Retrieved 2008-06-27. [dead link]
- ^ "Common View GPS Time Transfer". nist.gov. http://tf.nist.gov/time/commonviewgps.htm. Retrieved 2011-Jul-23.
- ^ "Spotlight GPS pet locator". Spotlightgps.com. http://www.spotlightgps.com/. Retrieved 2010-10-15.
- ^ Arms Control Association.Missile Technology Control Regime. Retrieved May 17, 2006.
- ^ "Commanders Digital Assistant explanation and photo". Web.archive.org. 2007-12-01. Archived from the original on 2007-12-01. http://web.archive.org/web/20071201034857/http://peosoldier.army.mil/factsheets/SWAR_LW_DBCS.pdf. Retrieved 2011-11-06.
- ^ "Latest version Commanders Digital Assistant" (PDF). http://peosoldier.army.mil/factsheets/SWAR_LW_CDA.pdf. Retrieved 2009-10-13. [dead link]
- ^ "Soldier Digital Assistant explanation and photo". Web.archive.org. 2008-06-10. Archived from the original on 2008-06-10. http://web.archive.org/web/20080610092154/http://www.army-technology.com/contractors/computers/lago/lago6.html. Retrieved 2011-11-06.
- ^ Sinha, Vandana (2003-07-24). "Commanders and Soldiers' GPS-receivers". Gcn.com. http://gcn.com/articles/2003/07/24/soldiers-take-digital-assistants-to-war.aspx. Retrieved 2009-10-13.
- ^ "XM982 Excalibur Precision Guided Extended Range Artillery Projectile". GlobalSecurity.org. 2007-05-29. http://www.globalsecurity.org/military/systems/munitions/m982-155.htm. Retrieved 2007-09-26.
- ^ Sandia National Laboratory's Nonproliferation programs and arms control technology.
- ^ Dr. Dennis D. McCrady. "The GPS Burst Detector W-Sensor". Sandia National Laboratories. http://www.osti.gov/bridge/servlets/purl/10176800-S2tU7w/native/10176800.pdf.
- ^ "Satellite message format". Gpsinformation.net. http://gpsinformation.net/gpssignal.htm. Retrieved 2010-10-15.
- ^ Michael Woessner, Anja Koehne. "time-of-week". Kowoma.de. http://www.kowoma.de/en/gps/data_composition.htm. Retrieved 2010-10-15.
- ^ "Interface Specification IS-GPS-200, Revision D: Navstar GPS Space Segment/Navigation User Interfaces" (PDF). Navstar GPS Joint Program Office. http://www.losangeles.af.mil/shared/media/document/AFD-070803-059.pdf. Page 103.
- ^ Misra, Pratap; Enge, Per (2006). Global Positioning System. Signals, Measurements and Performance (2nd ed.). Ganga-Jamuna Press. p. 115. ISBN 0-9709544-1-7. http://books.google.com/books?id=pv5MAQAAIAAJ.
- ^ Borre, Kai; M. Akos, Dennis; Bertelsen, Nicolaj; Rinder, Peter; Jensen, Søren Holdt (2007). A Software-Defined GPS and Galileo Receiver. A single-Frequency Approach. Springer. p. 18. ISBN 0-8176-4390-7. http://books.google.com/books?id=x2g6XTEkb8oC.
- ^ How GPS works. Konowa.de (2005).
- ^ TextGenerator Version 2.0. "United States Nuclear Detonation Detection System (USNDS)". Fas.org. http://www.fas.org/spp/military/program/nssrm/initiatives/usnds.htm. Retrieved 2011-11-06.
- ^ First GPS IIF Satellite Undergoes Environmental Testing. GPS World. November 5, 2007.
- ^ "Air Force Successfully Transmits an L5 Signal From GPS IIR-20(M) Satellite". LA AFB News Release. http://www.losangeles.af.mil/news/story.asp?storyID=123144001. Retrieved 20 June 2011.
- ^ "Federal Communications Commission Presented Evidence of GPS Signal Interference". GPS World. http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029?utm_source=GPS&utm_medium=email&utm_campaign=Navigate_01_31_2011&utm_content=data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029. Retrieved 2011-11-06.
- ^ "Coalition to Save Our GPS". Saveourgps.org. http://www.saveourgps.org/studies-reports.aspx. Retrieved 2011-11-06.
- ^ "LightSquared Tests Confirm GPS Jamming". Aviation Week. http://www.aviationweek.com/aw/generic/story.jsp?id=news/awx/2011/06/09/awx_06_09_2011_p0-334122.xml&headline=LightSquared%20Tests%20Confirm%20GPS%20Jamming&channel=busav. Retrieved 20 June 2011.
- ^ "GPS Almanacs, NANUS, and Ops Advisories (including archives)". GPS Almanac Information. United States Coast Guard. http://www.navcen.uscg.gov/?pageName=gpsAlmanacs. Retrieved 2009-09-09.
- ^ "George, M., Hamid, M., and Miller A. Gold Code Generators in Virtex DevicesPDF (126 KB)
- ^ Bancroft, S. (January 1985). "An Algebraic Solution of the GPS Equations". IEEE Transactions on Aerospace and Electronic Systems AES-21: 56–59. DOI:10.1109/TAES.1985.310538. http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4104017.
- ^ a b "Global Positioning Systems" (PDF). http://www.macalester.edu/~halverson/math36/GPS.pdf. Retrieved 2010-10-15.
- ^ Position Determination with GPS. Konowa.de (2005).
- ^ How GPS Receivers Work at How Stuff Works
- ^ a b c d Press, Flannery, Tekolsky, and Vetterling 1986, Numerical Recipes, The Art of Scientific Computing (Cambridge University Press).
- ^ "Determination of GPS receiver position using Multivariate Newton-Raphson Technique for over specified cases". http://www.thefreelibrary.com/Determination+of+GPS+receiver+position+using+Multivariate...-a0216041321.
- ^ Dana, Peter H.. "Geometric Dilution of Precision (GDOP) and Visibility". University of Colorado at Boulder. http://www.colorado.edu/geography/gcraft/notes/gps/gps.html#Gdop. Retrieved 2008-07-07.
- ^ Peter H. Dana. "Receiver Position, Velocity, and Time". University of Colorado at Boulder. http://www.colorado.edu/geography/gcraft/notes/gps/gps.html#PosVelTime. Retrieved 2008-07-07.
- ^ IPN Progess Report 42-159 (2004)
- ^ "NAVSTAR GPS User Equipment Introduction" (PDF). http://www.navcen.uscg.gov/pubs/gps/gpsuser/gpsuser.pdf. Section 1.2.2
- ^ David W. Allan (1997). "The Science of Timekeeping". Hewlett Packard. http://www.allanstime.com/Publications/DWA/Science_Timekeeping/index.html.
- ^ "Between-Satellite Differencing". Gmat.unsw.edu.au. http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/633.htm. Retrieved 2010-10-15.
- ^ "Double differencing". Gmat.unsw.edu.au. http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/635.htm. Retrieved 2010-10-15.
- ^ "Triple differencing". Gmat.unsw.edu.au. http://www.gmat.unsw.edu.au/snap/gps/gps_survey/chap6/636.htm. Retrieved 2010-10-15.
- ^ chapter on root finding and nonlinear sets of equations
- ^ Preview of Root Finding. Books.google.com. 2007. ISBN 978-0-521-88068-8. http://books.google.com/?id=UQW_VL2H56IC&pg=PA959&lpg=PA959&dq=%22Numerical+Analysis%22+multidimension++root+finding#PPA442,M1. Retrieved 2010-10-15.
- ^ "2011 John Deere StarFire 3000 Operator Manual". John Deere. http://stellarsupport.deere.com/en_US/support/pdf/om/en/ompfp11008_sf3000.pdf. Retrieved 2011-11-13.
- ^ a b "Federal Communications Commission Report and Order In the Matter of Fixed and Mobile Services in the Mobile Satellite Service Bands at 1525-1559 MHz and 1626.5-1660.5 MHz". FCC.gov. 6 April 2011. http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-11-57A1.pdf. Retrieved 2011-12-13.
- ^ "Federal Communications Commission Table of Frequency Allocations". FCC.gov. 18 November 2011. http://transition.fcc.gov/oet/spectrum/table/fcctable.pdf. Retrieved 2011-12-13.
- ^ "FCC Docket File Number: SATASG2001030200017, "Mobile Satellite Ventures LLC Application for Assignment and Modification of Licenses and for Authority to Launch and Operate a Next-Generation Mobile Satellite System"". FCC.gov. March 1, 2001. pp. 9. http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/reports/related_filing.hts?f_key=200647&f_number=SATASG2001030200017.
- ^ "U.S. GPS Industry Council Petition to the FCC to adopt OOBE limits jointly proposed by MSV and the Industry Council". FCC.gov. 4 September 2003. http://fjallfoss.fcc.gov/ecfs/document/view?id=6515082621. Retrieved 2011-12-13.
- ^ "Federal Communications Commission Order and Authorization Granting Authority". FCC.gov. 8 November 2004. http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-04-3553A1.pdf. Retrieved 2011-12-13.
- ^ "Statement of Julius P. Knapp, Chief, Office of Engineering and Technology, Federal Communications Commission". gps.gov. 15 September 2011. pp. 3. http://www.gps.gov/congress/hearings/2011-09-HASC/knapp.pdf. Retrieved 2011-12-13.
- ^ "FCC Order, Granted LightSquared Subsidiary LLC, a Mobile Satellite Service licensee in the L-Band, a conditional waiver of the Ancillary Terrestrial Component "integrated service" rule". Federal Communications Commission. FCC.Gov. 26 January 2011. http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-11-133A1.pdf. Retrieved 2011-12-13.
- ^ "Data Shows Disastrous GPS Jamming from FCC-Approved Broadcaster". gpsworld.com. 1 February 2011. http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029. Retrieved 10 February 2011.
- ^ "Javad Ashjaee GPS World webinar". gpsworld.com. 8 December 2011. http://www.gpsworld.com/gnss-system/news/javad-ashjaee-discuss-javad-gnss-lightsquared-tech-december-8-webinar-12337. Retrieved 2011-12-13.
- ^ "FCC Order permitting mobile satellite services providers to provide an ancillary terrestrial component (ATC) to their satellite systems". Federal Communications Commission. FCC.gov. 2003-02-10. http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-03-15A1.pdf. Retrieved 2011-12-13.
- ^ "Federal Communications Commission Fixed and Mobile Services in the Mobile Satellite Service". Federal Communications Commission. FCC.gov. 2010-07-15. http://www.federalregister.gov/articles/2010/08/16/2010-19824/fixed-and-mobile-services-in-the-mobile-satellite-service#p-31. Retrieved 2011-12-13.
- ^ http://saveourgps.org/pdf/SIS_DOD_Response_Statement_08122011.pdf
- ^ "Coalition to Save Our GPS". Saveourgps.org. http://saveourgps.org/. Retrieved 2011-11-06.
- ^ Jeff Carlisle (23 June 2011). "Testimony of Jeff Carlisle, LightSquared Executive Vice President of Regulatory Affairs and Public Policy to U.S. House Subcommittee on Aviation and Subcommittee on Coast Guard and Maritime Transportation". http://ssv.cachefly.net/lightsquared/wp-content/uploads/2011/06/LSQ-Testimony-Package.pdf. Retrieved 2011-12-13.
- ^ Julius Genachowski (31 May 2011). "FCC Chairman Genachowski Letter to Senator Charles Grassley". http://www.lightsquared.com/documents/FCC%20Julius%20Genachowski%20letter%20to%20Senator%20Grassley%20-%20May%2031,%202011.pdf. Retrieved 2011-12-13.
- ^ a b Tessler, Joelle (2011-04-07). "Internet network may jam GPS in cars, jets". The Sun News. http://www.thesunnews.com/2011/04/07/2085752/internet-network-may-jam-gps-in.html. Retrieved 2011-04-07.
- ^ FCC press release "" Spokesperson Statement on NTIA Letter--LightSquared and GPS " February 14, 2012
- ^ Paul Riegler, FBT. "FCC Bars LightSquared Broadband Network Plan." February 14, 2012. Retrieved February 14, 2012.
- ^ Orbital periods and speeds are calculated using the relations 4π²R³ = T²GM and V²R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×10−11 Nm²/kg², M = mass of Earth ≈ 5.98×1024 kg.
- ^ Beidou coverage
- ^ "Beidou satellite navigation system to cover whole world in 2020". Eng.chinamil.com.cn. http://eng.chinamil.com.cn/news-channels/china-military-news/2010-05/20/content_4222569.htm. Retrieved 2010-10-15.
- ^ Levin, Dan (2009-03-23). "Chinese Square Off With Europe in Space". China: NYTimes.com. http://www.nytimes.com/2009/03/23/technology/23iht-galileo23.html?_r=1&scp=1&sq=chinese%20europe%20galileo&st=cse. Retrieved 2011-11-06.
- ^ "ASM, News on GIS, GNSS, spatial information, remote sensing, mapping and surveying technologies for Asia". Asmmag.com. http://www.asmmag.com/news/india-to-launch-1st-irnss-satellite-by-december. Retrieved 2009-10-13. [dead link]
- "NAVSTAR GPS User Equipment Introduction" (PDF). United States Coast Guard. September 1996. http://www.navcen.uscg.gov/pubs/gps/gpsuser/gpsuser.pdf.
Further reading[link]
- Parkinson; Spilker (1996). The global positioning system. American Institute of Aeronautics and Astronautics. ISBN 978-1-56347-106-3. http://books.google.com/?id=lvI1a5J_4ewC.
- Jaizki Mendizabal; Roc Berenguer; Juan Melendez (2009). GPS and Galileo. McGraw Hill. ISBN 978-0-07-159869-9. http://books.google.com/?id=t1lBTH42mOcC&printsec=frontcover&dq=GPS+and+GALILEO#v=onepage&q&f=false.
- Nathaniel Bowditch (2002). The American Practical Navigator – Chapter 11 Satellite Navigation. United States government.
External links[link]
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Wikimedia Commons has media related to: Global Positioning System |
- Global Positioning System at the Open Directory Project
- Air Force Space Command GPS Operations Center homepage
- FAA GPS FAQ
- GPS.gov—General public education website created by the U.S. Government
- National Space-Based PNT Executive Committee established 2004 to oversee management of GPS and GPS augmentations at national level
- USCG Navigation Center—Status of the GPS constellation, government policy, and links to other references; includes satellite almanac data.
- The GPS Program Office (GPS Wing)—Responsible for designing and acquiring the system on behalf of the United States Government.
- U.S. Army Corps of Engineers manual: NAVSTAR HTML and PDF (22.6 MB, 328 pages)
- National Geodetic Survey Orbits for the Global Positioning System satellites in the Global Navigation Satellite System
- GPS SPS Performance Standard—The official Standard Positioning Service specification (2008 version).
- GPS SPS Performance Standard—The official Standard Positioning Service specification (2001 version).
- GPS PPS Performance Standard—The official Precise Positioning Service specification.
- Satellite Navigation: GPS & Galileo (PDF)—16-page paper about the history and working of GPS, touching on the upcoming Galileo
- Average Latitude & Longitude of Countries
- A comprehensive online tutorial on GPS Principles and Real Time Kinematic positioning techniques by Tekmon Geomatics
- "Sources of Errors in GPS"
- GPS and GLONASS Simulation (Java applet) Simulation and graphical depiction of space vehicle motion including computation of dilution of precision (DOP)
- University of New South Wales: Carrier Phase Measurement
- University of New South Wales: Carrier Beat Phase
- GPS jamming – As the uses of satellite-positioning technology continue to grow, what can be done to stop deliberate and dangerous jamming of the signals? The Economist
- GeoCheckpointing - game for GPS users
- GPS Coordinates
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This article is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License, which means that you can copy and modify it as long as the entire work (including additions) remains under this license.
