基于数值计算的机载SAR空变运动补偿算法

针对机载合成孔径雷达(SAR)高分辨率宽测绘带(HRWS)成像问题,在分析结合两步运动误差补偿的距离徙动算法基础上,提出一种基于数值计算的空变运动误差补偿算法。通过对粗聚焦图像进行分块,在子块的两维波数域进行空变运动补偿,补偿的相位包括方位相位误差、距离相位误差以及方位和距离的耦合相位,因此该算法在复杂航迹、高分辨和宽测绘带情况下仍具有较好的鲁棒性。最后对SAR仿真数据和实测数据进行处理,并与结合两步运动误差补偿的距离徙动算法进行比较,处理结果表明该算法能够更好地补偿空变运动误差。

Airborne SAR space-variant motion compensation algorithm based on numerical calculation

Aimed at the imaging problems of high resolution wide swath (HRWS) airborne synthetic aperture radar (SAR), on the basis of conventional range migration algorithm with integrated two-step motion compensation, a new space-variant motion compensation algorithm based on numerical calculation is proposed for HRWS airborne SAR. This algorithm compensates the spatial-variant motion error in the two-dimensional wavenumber domain by transforming the coarsely focused image to block. The compensated phase includes azimuth phase error, range phase error and the coupling phase of range and azimuth. So the proposed algorithm can work well for the HRWS SAR data with complex flight path. Finally, The new proposed algorithm is compared with range migration algorithm with integrated two-step motion compensation by processing simulation data and real data. Real data processing results demonstrate that the algorithm can better compensate the spatial-variant motion error.