复杂航迹和起伏地形条件下机载聚束SAR空变运动补偿

Space-variant Motion Compensation for Airborne Spotlight SAR Under Complicated Flight Path and Rugged Terrain

运动补偿是雷达平台机动飞行条件下合成孔径雷达(SAR)实现精确聚焦成像的前提,而如何精确实现运动误差的空变补偿(误差补偿随目标距离、方位和高度位置的变化而变化)目前还存在很大的挑战。本文提出了一种新的三阶运动补偿方法,能够有效解决复杂雷达航迹和地形起伏条件下运动误差的空变补偿问题。该方法首先以场景中心为参考进行空不变运动补偿,然后以多个子场景中心为参考进行空变运动补偿,最后再利用极坐标格式算法(PFA)统一补偿每个像素的空变误差。仿真数据处理结果验证了本文方法的有效性。

Motion compensation is often a prerequisite to get focused synthetic aperture radar （SAR） images with compllcated radar platform flight paths. How to implement accurate motion error compensation is still a great challenge, since the error has inherent space-variant property. In this paper, a threeorder motion compensation strategy is proposed. The first order compensation corrects the spaceinvariant motion error by using scene center as a reference. Then, digital spotlight preprocessing is applied to partially compensate the spacevariant error. Finally, the residual spacevariant error in subpatch is corrected by the polar format algirhtm （PFA）. Simulation results show that the proposed method can provide accurate image formation even under conditions of complicated radar flight paths and rugged imaging terrain.