Terrain data aided passive ground target tracking

The primary purpose of passive tracking function is to support weapon systems on the military aircraft. A ground-attacking aircraft must know the precise location of the target to fulfill its missions. The target tracking system must estimate location of the target passively, if the need of stealth performance is highly required. A target is designated using integrated sensors, such as Helmet Mounted Sights, Laser Designators, FLIR (Forward-Looking Infrared Radar), IRSTs (Infra-Red Search and Track), and RF Precision Direction Finding Equipments. These sensors can accurately provide the LOS (Line Of Sight) angle measurements to a ground target passively, but they cannot provide a measurement of range which is required to determine the location of targets on the ground. However, by using of stored digital terrain data, the target's location can be calculated. The digital terrain aided passive target tracking algorithm consists of the LOS intersection algorithm and the Kalman Filter.