Algorithm and implementation of phase error compensation for airborne SAR

Based on Doppler parameter estimation and Phase Gradient Autofocus algorithm, a method of gradually compensating phase error is presented. Doppler parameter estimation algorithm can be capable of removing linear phase error and quadratic phase error produced by movement error of Airborne which mostly decide imaging quality. PGA algorithm can compensate cubic phase error and high-degree error caused by media disproportionation of electromagnetic transmission. Combining two methods can effectively compensate phase error in SAR imaging and achieve high resolution-accuracy imaging. This paper utilizes measured data to accomplish wide-range imaging and verifies the algorithm. Finally by theoretical analysis for imaging effect, imaging actual physical process and affecting factors which depict imaging area coverage are derived.