机载并行双站大斜视SAR两步式成像算法

摘要

A two-step imaging algorithm for focusing airborne parallel high squint Synthetic Aperture Radar (SAR) data is proposed in this paper. For the serious cross coupling of echo signal in bistatic high squint SAR, Linear Range Walk Correction (LRWC) is performed in range frequency-azimuth time domain to correct the large LRW induced by the high squint model of receiver and transmitter. A Modified Bistatic Point Target Reference Spectrum (MBPTRS) is derived, and residual Range Cell Migration (RCM) is corrected by Chirp Scaling (CS) method to get the focusing result. To solve the target position displacements in the focusing result, a method of target position correction that converts the focusing image to the ground plane is derived. Finally, the experimental results with simulated data validate the effectiveness of the proposed two-step imaging algorithm and the method of target position correction.%该文提出了机载并行双站大斜视SAR的两步式成像算法。针对双站大斜视回波信号的距离-方位强耦合，在距离频域-方位时域校正收、发载机大斜视引起的大距离走动，然后推导改进点目标频谱公式，并用Chirp Scaling方法校正残余距离徙动得到成像结果。针对成像结果中出现的点目标位置偏移的问题，推导了成像场景到地面场景的目标位置校正方法。最后，通过仿真验证了所提的两步式成像算法和目标位置校正方法的有效性。