A Modified PGA for Spaceborne SAR Scintillation Compensation Based on the Weighted Maximum Likelihood Estimator and Data Division

The P-band spaceborne synthetic aperture radar (SAR) is significantly affected by ionospheric scintillation. Although the traditional phase gradient autofocus (PGA) can estimate and compensate scintillation of single polarization SAR data, quality refocused image will degrade at scene edge. In this paper, a modified PGA based on weighted maximum likelihood (WML) estimator data division proposed for full-scene refocusing. First, strategy corrupted introduced, which prior information including its power spectral density (PSD) autocorrelation function (ACF). Then, some pre-processing steps selection, circular shifting windowing are performed suppressing noise clutter. Finally, estimated WML with fewer iterations, after all blocks obtained, distorted refocused. Using generated wide-band model (WBMOD) screen, numerical simulations point targets scenes derived from real carried out. evaluation results about resolution, peak side-lobe ratio (PSLR), integral (ISLR), correlation coefficient entropy demonstrate effectiveness algorithm.