A Novel Motion Compensation Approach for Airborne Spotlight SAR of High-Resolution and High-Squint Mode

This letter proposes a new motion compensation approach for high-squint and high-resolution airborne spotlight synthetic aperture radar (SAR) integrated with polar format algorithm (PFA). The motion error is coarsely compensated by means of measuring systems. In PFA, the expressions of the line-of-sight polar interpolation are first explicitly revealed, and the nonsystematic range cell migration (NsRCM) induced by residual motion error is also corrected, which paves the way for autofocus application. After the NsRCM correction, the enhanced total least square estimator-based phase adjustment by contrast enhancement (PACE) algorithm is considered to account for the residual phase errors extended to the range-dependent case. The processing results of airborne SAR real data are presented to demonstrate the validity of the proposed algorithm.