Analysis of Faraday rotation on spaceborne CTLR compact polarimetric SAR image reconstruction

Abstract

The CTLR (circular transmit and linear receive) compact polarimetric (CP) synthetic aperture radar (SAR) system transmits only right or left circular polarized signal and receives H and V linear polarized signal. CP SAR mode has significant advantage of doubled swath width compared to the traditional full-polarimetry (FP) mode. In this paper, the effective FP data are reconstructed using Souyris' iteration algorithm from the covariance matrix of the CTLR mode CP SAR data. Then the performance of the algorithm is analyzed. Moreover, the ionospheric effect of Faraday rotation (FR) on longer wavelength (i.e. P-band) spaceborne CP SAR was introduced in the simulation. After simulating the impacts of FR on SAR image reconstruction, an information-theoretical evaluation method was proposed for analyzing the quality of SAR image reconstruction. The mutual information between the original FP data and the reconstructed FP data (namely, from the CTLR CP SAR image) as a function of FR was illustrated, for quantitatively evaluating FR on longer wavelength (e.g. P-band) spaceborne CTLR CP SAR image reconstruction.