Calibration concept for the TerraSAR-X instrument

The paper describes the calibration measures planned for the TerraSAR-X SAR instrument, due for launch in 2005. TerraSAR-X is a high-resolution X-Band SAR satellite that operates in Strip-map, Spotlight and ScanSAR modes and has selectable or dual polarization. It can image on the left or right side of the sub-satellite track, which is achieved by rolling the satellite. There are also experimental modes for wide bandwidth, providing even higher resolution, as well as for full polarization and along track interferometry (ATI), the latter two being achieved by splitting the receive antenna into two halves. Due to the high degree of flexibility of the instrument, e.g. the large number of modes and possible antenna beams, and the tight performance requirements, the calibration of the sensor is a major challenge and new concepts are needed to keep the costs affordable.