ABSTRACT
“Navigation” is the determination of the position and velocity of a moving vehicle, on land, at sea, in the air, or in space. In the usual navigation system, the state vector is derived on board, displayed to the crew, recorded on board, or transmitted to the ground. Navigation information is usually sent to other onboard subsystems such as waypoint steering, communication control, display, weapon-control, and electronic warfare (emission detection and jamming) computers. Dead-reckoning navigation systems derive their state vectors from a continuous series of measurements beginning at a known initial position. Mapping navigation systems observe and recognize images of the ground, profiles of altitude, sequences of turns, or external features. An onboard computer resolves the accelerations into navigation coordinates and integrates the components of acceleration once to obtain velocity and again to obtain position. During the 1990s, Russia deployed a satellite navigation system, incompatible with global positioning system, called GLONASS.
