Fast algorithm for airborne SAR range cell migration correction
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摘要: 距离-多普勒算法是机载合成孔径雷达成像信号处理中的常用算法,针对其采用逐点插值进行距离徙动修正而导致运算量过大的问题,提出了一种无需插值的快速距离徙动修正方法.该算法通过二次快速傅里叶变换和一次复乘操作完成合成孔径雷达成像所需的距离徙动修正处理.在分析回波信号模型的基础上,推导了利用该技术能够精确完成距离徙动修正的最大测绘带宽度,给出了该宽度与成像分辨率之间的关系,并用计算机仿真验证了上述关系的正确性.理论分析、仿真和实测数据处理结果表明,该方法具有运算量小、精度高的优点,非常适合于机上实时处理.Abstract: The range-Doppler algorithm is quite popular in airborne synthetic aperture radar (SAR) image formation. To reduce the excessive computation load associated with the pixel by pixel interpolation required in traditional range Doppler algorithm (RDA) to remove range cell migration (RCM), a fast and interpolation-free range cell migration correction(RCMC) technique which only involves operations of two FFTs and one complex multiplication was proposed. Based on the analysis of echo signal model, the constraint on attainable maximum swath with such a fast RCMC technique was derived, and the relation between this constraint and the imaging resolution was also given. The analysis was validated by simulation results. The theoretical analysis, simulation and SAR real data processing result show that this technique can reduce the computational burden dramatically with high enough precision, and is amenable to on-board real time processing.
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