一种SAR两维自聚焦算法的FPGA实现

摘要

For real-time autofocus of defocused images produced by Synthetic Aperture Radar (SAR), the two-dimensional autofocus approach proposed in this study is used to correct the residual range cell migration and compensate for the phase error. Next, a block-wise Phase Gradient Autofocus (PGA) is used to correct the space-variant phase error. The Field-Programmable Gate Array (FPGA) design procedures, resource utilization, processing speed, accuracy, and autofocus are discussed in detail. The system is able to autofocus an 8K × 8K complex image with single precision within 5.7 s when the FPGA works at 200 MHz. The processing of the measured data verifies the effectiveness and real-time capability of the proposed method.%为实时完成合成孔径雷达(SAR)散焦图像的自聚焦，该文提出了一种能够校正残留距离徙动并且适用于空变误差场景的2维自聚焦处理方案。该方案首先利用2维自聚焦算法同时校正残留距离徙动和粗略补偿相位误差，然后进行分块PGA校正空变误差。文中详细阐述了该方案的FPGA设计过程，并对资源占用、运算速度、精度和聚焦效果进行了分析。当FPGA工作在200 MHz时，系统可在5.7 s内完成了8K×8K点单精度复图像的自聚焦处理。实测数据处理结果充分验证了该系统的实时性和有效性。