基于空变分离的两步聚焦双基曲线合成孔径雷达成像

doi:10.12382/bgxb.2021.0398

摘要/Abstract

摘要： 针对任意构型曲线运动轨迹双基SAR严重的二维空变问题，建立斜距的空变分离等效模型，并在此基础上提出一种两步聚焦处理方法。在距离频域-方位时域对回波进行非空变相位补偿，以完成距离走动矫正和Deramp处理，实现粗聚焦。第一步聚焦后的剩余相位是与点目标位置有关的空变部分，接着在距离向引入Keystone变换，并在方位向通过多普勒参数的最小二乘拟合和方位重采样较好地补偿空变相位误差，完成精确聚焦。仿真结果表明：所提空变分离的斜距等效模型具有较高的精确性；两步聚焦处理算法有效地解决了曲线双基合成孔径雷达的二维空变和强耦合问题，提高了边缘点的成像性能，具有较大的成像区域和较广的使用场景。

关键词: 双基合成孔径雷达, 空变分离, 曲线运动, Keystone变换, 最小二乘拟合, 方位重采样

Abstract: To solve the severe two-dimensional space-variant issue of different configurations of bistatic SAR with curvilinear trajectory，a two-step processing method based on space-variant separation is proposed. First，space-invariant phase compensation is performed on the echo in the range frequency domain-azimuth time domain to conduct range migration correction and Deramp processing，and achieve coarse focusing. The residual phase is the space-variant part related to the position of the point target after the first step of focusing. Then the Keystone transformation is introduced to the range direction，and the least square fitting of Doppler parameters and azimuth resampling in the azimuth direction are derived，compensating the space-variant phase error and completing precise focusing. Simulation results show that the proposed slanting distance equivalent model based on space-variable separation has high accuracy. The two-step algorithm effectively relieves two-dimensional space variation and strong coupling of the curvilinear bistatic SAR，improving the imaging performance of edge points，realizing a large imaging area，and demonstrating a wide range of scenarios.

Key words: bistaticsyntheticapertureradar, space-variantseparation, curvilinearmotion, keystonetransformation, leastsquarefitting, azimuthresampling

中图分类号:

TN957.52

徐熙毅，谭鸽伟，李彪. 基于空变分离的两步聚焦双基曲线合成孔径雷达成像[J]. 兵工学报, 2022, 43(6): 1365-1375.

XU Xiyi， TAN Gewei， LI Biao. Two-step Imaging of Bistatic SAR with Curvilinear Trajectory Based on Space-Variant Separation[J]. Acta Armamentarii, 2022, 43(6): 1365-1375.

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