Calibration of SIR-C data products

The SIR-C/X-SAR imaging radar flew on the Space Shuttle Endeavour in April and October of 1994. This multi-frequency radar has fully polarimetric capability at L- and C-band, and a single polarization at X-band (XSAR). Analysis of data collected during the two missions reveals that the SIR-C system performed better than expected in terms of image quality and calibration. The cross-talk and phase stability of both systems has been exceptionally good. Calibration of polarimetric L- and C-band data for all the different modes SIR-C offers has been achieved by analysis of pre-flight test data to come up with a model of the system, analysis of in-flight test data to determine the actual antenna pattern and gains of the system during operation, and analysis of data from calibration sites distributed around the SIR-C/X-SAR orbit track. The SIR-C missions are the first multi-frequency polarimetric imaging radar employing a phased array antenna flown in space. The objectives of flying two missions in one year included the study of seasonal changes in the Earth´s environment. In this paper, calibration results from both SIR-C/X-SAR missions are presented