Digital terrain elevation mapping system

The Lockheed Martin Digital Terrain Elevation Mapping System (DTEMS) will be a commercial system for collection processing and archive of sub-meter precision digital terrain matrix (DTM) and three-meter resolution ortho-rectified digital polarimetric synthetic aperture radar (SAR) imagery. DTEMS will also produce commercial cartographic, terrain display, and topographic engineering products. DTEMS will use a synthetic aperture radar (SAR) mounted in an ER-2 aircraft to obtain stereo polarimetric X-band SAR images. The SAR images will be processed to obtain estimates of the horizontal position and elevation at postings separated horizontally by three meters. These estimates will be used to form the DTM. In turn, the DTM will be used to geometrically correct and ortho-rectify the polarimetric SAR images. To minimize the operational costs, the system will collect data simultaneously on both sides of the aircraft. The effective area coverage rate will exceed 700 km²/minute. For terrain with slopes of 45 degree or less, DTEMS will deliver DTMs with average one σ elevation precision of 0.3 meter, average absolute one σ elevation precision less than 0.6 meter, and three meter post spacing (posting). DTEMS data will satisfy National Map Accuracy Standards (NMAS) contour intervals of two to three meters