Calibration of RCM Compact Modes

Abstract

The RADARSAT Constellation Mission (RCM) planned for launch in June 2019 will involve three small SAR satellites flying in a constellation configuration. Each satellite SAR will be equipped with Compact (i.e. Hybrid) capabilities in addition to single-polarization (HH, HV, VV), and conventional (HH-HV, VV-VH, and HH-VV) dual-polarization. Compact (CP) SAR transmits a circular polarization and measures the received signal at the horizontal and vertical antenna polarization. It is now admitted that the actual SAR technology does not permit the generation of a perfectly circular polarization and this may significantly affect CP information [1], [2]. All the existing CP calibration models are mainly based on the Freeman CP model [3], which assumes that the transmitted polarization is perfectly circular. Recently, a new CP calibration mode [2], [4], which explicitly takes into account the non circularity of transmitted polarization, in addition to conventional antenna distortion matrix channel imbalance and Faraday rotation contamination, is introduced and validated using ALOS2-CP data [2], [5]. In this study, the new CP calibration model will be adapted to the RCM. The strategy adopted for RCM CP calibration is described. Preliminary results obtained with RCM data will be presented at the conference.