Polarimetric Measurements for Sentinel-1 and Radarsat Constellation Mission using Reference Point Targets

Abstract

The paper focuses on polarimetric measurements executed for two C-Band SAR missions: Sentinel-1 (S1) and Radarsat Constellation Mission (RCM). RCM is able to operate as a quad-pol system which transmits alternating-ly H and V polarization pulses and receives H and V simultaneously. In contrast to this, S1 is implemented as du-al-polarization system which transmits either H or V polarization for a specific acquisition and receives both H and V polarization simultaneously. For this purpose, reference point targets have been used to allow a compari-son of the impulse response function derived from the different polarization channels. While trihedral corner re-flectors allow to compare co-polarized channels only, transponders are used for analyzing all four polarization channels (HH, VV, HV and VH). In order to enable a comparison of all four polarization channels also for S1, longer time series of acquisitions over stable reference targets have been acquired. The results show that the po-larization channels are well balanced for both SAR missions. The channel imbalance between the polarization channels is low for all pairs in particular between co-polarized channels (HH-VV) but also for cross-polarized channels (HV-VH).