Concurrent Internal Calibration of Spaceborne SAR Systems

Abstract:
The internal calibration of a SAR instrument is required to guaranty the stability of the instrument hardware over time. Unfortunately most of the current internal calibration schemes cause an interruption of the SAR data acquisition during internal calibration and hence a reduction of the acquisition time and quality for each target. An advanced internal calibration scheme is introduced which allows continuous internal calibration during a data take by injecting a coded signal into the signal path during the radar receive window. The avoidance of gaps due to internal calibration is important for future SAR missions allowing data acquisition over long periods of time (several 10 min). The performance of some coding scheme which can be used for the introduced internal calibration is analyzed using real TerraSAR-X L0 data.