距离走动校正的距离空变分析与补偿

Range-Dependent Range Walk Correction Analysis and Compensation

斜视角的距离空变导致距离走动校正存在距离空变。文中分析了距离走动校正距离空变对成像的影响,发现距离走动校正空变导致目标图像在近距端和远距端向反方向漂移。在前斜视SAR中,距离场景近端目标向左漂移若干像素,距离场景远端目标向右漂移若干像素。距离走动校正空变不仅造成场景的扭曲,在高分辨大斜视下还会使图像散焦。文中给出了距离走动校正距离空变补偿方法,所提方法可与常规的二次补偿结合进行,不会增加额外的计算负担。仿真结果与理论分析一致,距离走动校正空变补偿后,场景近端和远端目标均能较好聚焦,实测数据成像实验也与理论分析相符。从而表明距离走动校正空变分析是正确的,距离走动校正空变补偿方法是有效的。

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 tar- gets 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 correc- tion. The proposed method operates with the second motion compensation and do not increase computation burden. Simula- tion 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 com- pensation method is effective.