Schied, Eberhard; Rostan, Friedhelm (EADS Astrium GmbH, Germany)
Østergaard, Allan; Traver, Ignacio Navas; Snoeij, Paul (ESA-ESTEC, The Netherlands)
The Sentinel-1 C-band SAR instrument implements an internal calibration system with a minimum of dedicated calibration elements. The transmit power times receiver gain product, PG, used for correction of the image data, is obtained from five types of calibrations measurements. Leakage signals from TX to RX are the main error sources on the calibration signals. Their impact is minimised by the PCC2 (pulse coded calibration) technique. An RF Characterization mode is implemented to monitor individual elements of the antenna. This mode is based on the PCC512 pulse coded calibration technique. The expected 3sigma accuracy for internal calibration of PG is about 0.3 dB/ 3deg. The expected 3sigma accuracy of RF characterization mode is about 0.4 dB / 5deg.