Helmet-mounted display
A helmet-mounted display (HMD) is a device used in some modern aircraft, especially combat aircraft. HMDs project information similar to that of head-up displays (HUD) on an aircrew’s visor or reticle, thereby allowing them to obtain situation awareness and/or cue weapons systems to the direction his head is pointing. Applications which allow cuing of weapon systems are referred to as helmet-mounted sight and display (HMSD) or helmet-mounted sights (HMS). These devices were created first by South Africa, then the Soviet Union and followed by the United States.
Requirement
Aviation HMD designs serve these purposes:
using the head angle as a pointer to direct air-to-air and air-to-ground weapons seekers or other sensors (e.g., radar, FLIR) to a target merely by pointing his head at the target and actuating a switch via HOTAS controls. In close combat prior to HMDs, the pilot had to align the aircraft to shoot at a target. HMDs allow the pilot to simply point his head at a target, designate it to weapon and shoot.