A Motion-error Estimation Method for Hight Squint SAR Combined with Azimuth-variant Phase Compensation

For high squint synthetic aperture radar (SAR) data processing, it is difficult to deal with the greatly coupled signal between range and azimuth. For mitigating this coupling and simplifying the following processing, the linear range walk correction(LRWC) is often introduced with sacrifice of the limitation of focus depth. In the current SAR imaging algorithms, the azimuth-variant phase compensation methods are established without consideration of motion errors and ignore the effects of azimuth-variant phase on motion-error estimation slightly. For this issue, a detail analysis on the effects of the LRWC and azimuth-variant phase is given, and then a motion-error estimation method combined with azimuth-variant phase compensation is proposed in this paper. The proposed method ensures the following data processing and improves the imaging quality of the final focusing. Both the simulation results and real data processing validate the effectiveness of the proposed method.