Before revision: Altitude matching Modern TERCOM systems use a different concept, based on the altitude of the ground over which missile flies and measure by radar altimeter of the missile and comparing that to measurements of prerecorded terrain altitude maps .
After revision: stored in missile avionics memoryAltitude matching Modern TERCOM systems use a different concept, based on the altitude of the ground over which missile flies and measure by radar altimeter of the missile and comparing that to measurements of prerecorded terrain altitude maps .