TERCOM

Terrain Contour Matching (TERCOM) is a terrain-aided navigation method that corrects position estimates by matching altimeter measurements against a stored digital elevation map (DEM). Developed by Boeing in the 1980s for cruise missile guidance, TERCOM enables accurate navigation in GPS-denied environments by exploiting the unique terrain signature at each location. TERCOM remains essential for missile guidance, autonomous underwater vehicles, and systems operating in jamming scenarios.