Motion Compensation for Highly Squinted SAR data based on Azimuth Nonlinear Chirp Scaling Algorithm

Abstract

In order to accommodate the motion errors caused by the actual trajectory, a lot of motion compensation (MOCO) methods have been developed. However, the typical two-step MOCO does not meet well-focused image requirements with the increasing of squint angle, higher order motion errors caused by acceleration need to be considered. In this paper, an extended azimuth non-linear chirp scaling (ANCS) algorithm is proposed to solve the problem, a real-time range distance expression containing acceleration is proposed. An accurate form of the signal spectrum is obtained by the method of series reversion and Extended Chirp Scaling algorithm (ECS) is applied to deal with the range focusing. Non-linear chirp scaling operation is proposed to deal with the azimuth focusing. The simulation results indicate that the extended ANCS algorithm achieves more accurate focus results than ECS algorithm.