Overview of the active TerraSAR-X calibrators and first results

This paper describes the development and system concept for an active and highly integrated, digitally controlled SAR system calibrator. For precise and high-quality SAR data, precise ground targets are necessary for external calibration of the SAR data. Compared to passive targets, active radar targets like transponders offer more features. The recording of the transmitted radar signals from the satellite becomes possible and allows additional data analysis and data correction. A total of 18 active transponder and receiver systems and 16 receiver only systems were fabricated for the TerraSAR-X calibration campaign in summer 2007 [1], [2], [3]. TerraSAR-X is the first German spaceborne X-band SAR satellite mission.