Effects of Polarization Distortion at Transmission and Faraday Rotation on Compact Polarimetric SAR System and Decomposition

In this letter, the influence of a polarization distortion at transmission and the Faraday rotation on compact polarimetric synthetic aperture radar (C-PolSAR) measurements is assessed. Polarization distortions at transmission for a C-PolSAR system can be introduced by nonideal transmission polarization waveforms, channel imbalance, and crosstalk. In addition, the Faraday rotation can also cause a distortion in a low-frequency spaceborne SAR system. The aforementioned two kinds of distortions have different influences on the measured data and the H/α̅ decomposition. This letter assesses the polarization quality of a C-PolSAR system and evaluates the various effects of errors on the compact polarimetric parameters, including polarimetric entropy H and α̅. Quality assessment and error analysis can be used to inform the C-PolSAR system design. Canadian AirSAR L-band data are used to assess the impact of the distortions on H/α̅.