Effects of Polarization Distortion at Transmission and Faraday Rotation on Compact Polarimetric SAR System and <inline-formula> <tex-math notation="LaTeX">$H/\bar{\alpha}$</tex-math></inline-formula> Decomposition

Abstract

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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H/\bar{\alpha} $</tex-math></inline-formula> decomposition. This letter assesses the polarization quality of a C-PolSAR system and evaluates the various effects of errors on the compact polarimetric parameters, including polarimetric entropy <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\bar{\alpha} $</tex-math></inline-formula> . Quality assessment and error analysis can be used to inform the C-PolSAR system design. Canadian AirSAR L-band data are used to assess the impact of the distortions on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H/\bar{\alpha}$</tex-math></inline-formula> .