A high accuracy calibration and receive instrument for TerraSAR-X ground calibration

TerraSAR-X is a new Earth observing satellite which is launched in spring 2006. It carries a high resolution X-band SAR sensor. For high image data quality, accurate ground calibration targets are necessary. This paper describes a novel system concept for an active and highly integrated, digitally controlled SAR system calibrator. A total of 16 active transponder and receiver systems and 17 receiver only systems will be fabricated for a calibration campaign. The calibration units serve for absolute radiometric calibration of the SAR image data. Additionally, they are equipped with an extra receiver path for 2D satellite antenna pattern recognition. The calibrator is monitored by a dedicated digital control unit. For antenna pattern estimation, an algorithm is presented.