A Novel Method for Polarization Orientation Angle Estimation Over Steep Terrain and Comparison of Deorientation Algorithms

This article proposes a novel polarization orientation angle (POA) estimation algorithm for steep terrain by applying physical scattering characteristics of natural surface. The algorithm extends the range of POA from [-45°, 45°] to (-90°,90°] and achieves consistent estimation with the widely used circular polarization algorithm (CPA) and minimum cross-polarization algorithm (MXPA) over flat area, but avoids the POA wrapping caused by the restriction of CPA and MXPA over precipitous area. Besides, detailed comparison among these deorientation algorithms is presented for clarifying their relations and analyzing the wrapping and unwrapping issue of POA. Both simulated data of Bragg scattering model and PolSAR data of L-band ALOS PALSAR and P-band NASA/JPL AIRSAR are used to substantiate the proposals.