Range-Dependent Range Walk Correction Analysis and Compensation

Range-dependent squint angle cause range-dependent range walk correction. This paper analyzes the impact of range-dependent range walk correction to imaging, and found that range-dependent range walk correction causes the target image shift to the opposite direction at the near and far end. In forward squint-looking mode SAR imaging the near end targets in range scene shift certain pixels to the left while the far end targets in range scene shift certain pixels to the right. Range-dependent range walk correction not only results in distortion of the scene, but also cause the image defocusing at high resolution high squint SAR system. This paper presents a compensation method for range-dependent range walk correction. The proposed method operates with the second motion compensation and do not increase computation burden. Simulation results are similar to theoretical analysis, after compensation with range-dependent range walk correction, targets in near and far end of scene can focus well, the real data imaging experiments are also consistent with theoretical analysis. Thus indicating range-dependent range walk correction analysis is correct, and range-dependent range walk correction compensation method is effective.