| Abstract |
TanDEM-X is a high-resolution interferometric SAR mission of DLR (German Aerospace Center), together with the partners EADS Astrium GmbH and Infoterra GmbH in a PPP (Public Private Partnership) consortium. The mission concept is based on a second TerraSAR-X radar satellite flying in close formation to achieve the desired interferometric baselines in a highly reconfigurable constellation. A contract to built the TanDEM-X spacecraft was signed in September 2006 between DLR and EADS Astrium.
The primary goal of the innovative TanDEM-X/TerraSAR-X constellation is the generation of a global, consistent, timely and high-precision DEM (Digital Elevation Model), corresponding to the HRTI-3 (High Resolution Terrain. Information-3) model specifications (12 m posting, 2 m relative height accuracy for flat terrain). The HRTI specifications were defined by NGA (National Geospatial-Intelligence Agency), Washington, D. C.
The achievable DEM height accuracy has been confirmed in Phase A by a detailed performance analysis taking into account all major system and scene parameters like the finite radiometric sensitivity of the individual radar sensors, co-registration and processing errors, range and azimuth ambiguities, baseline and Doppler decorrelation, the strength and orientation of surface and vegetation scattering, quantization errors, temporal and volume decorrelation, baseline estimation errors and the chosen independent post-spacing (horizontal resolution).
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