FPGA Implementation of a SAR Two-dimensional Autofocus Approach
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摘要: 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8K8K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。Abstract: For real-time autofocus of defocused images produced by Synthetic Aperture Radar (SAR), the twodimensional 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.
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