Map of Faraday rotation angle in Advanced Land Observing Satellite-2 full polarimetric data

Spaceborne synthetic aperture radar (SAR) systems operating at low frequency, such as L- and P-bands, are significantly influenced by ionospheric effects. One of the remarkable effects is Faraday rotation (FR), which is known as a serious error source for the polarimetric SAR (PolSAR) application. The FR effect mainly results from the background ionosphere so that the FR angles (FRAs) within a SAR image tend to take on a potential spatial-variable distribution. The typical estimator is used to accurately estimate FRA from the PolSAR data. Moreover, a step-to-step procedure is proposed to derive FRA map. On the basis of the real data processing, the experimental results validate the effectiveness of the FRA map, which indicates the immense capability of the PolSAR data to retrieve a spatial distribution of the FRA.