斜视滑动聚束模式SAR成像算法研究

摘要

当滑动聚束模式合成孔径雷达(SAR)工作在星载斜视或者大斜视、高分辨率机载情况下，由于距离方位耦合造成了一种新的现象2维频谱倾斜。它引起方位向频谱展宽和带宽增加，这导致一种新的方位向频谱混叠现象，传统的两步式成像算法不能消除这种频谱混叠效应。该文提出一种改进的两步式成像算法，它能有效地消除2维频谱倾斜造成的频谱混叠，同时不需要大量的补零操作，所以这种算法能高效地对斜视滑动聚束模式进行成像。文中详细介绍了该算法的处理流程，并与传统两步式成像算法进行了对比。最后利用仿真和实测数据，验证了改进的两步式成像算法在斜视滑动聚束模式下的有效性。%When the sliding spotlight mode SAR works in spaceborne squint case or airborne high-squint high-resolution case, the coupling between range and azimuth rises rapidly. It leads to a new two-dimensional (2-D) spectrum skew phenomenon. The skew extend the azimuth spectrum and enlarge the Doppler bandwidth, which causes a new azimuth spectral folding effect. The folding can not be eliminated by the conventional two-step processing algorithm. In this paper, a modified two-step processing algorithm is proposed. Efficiently implemented without large zero padding, it eliminates the effect of the 2-D spectrum skew. Therefore, the algorithm can process the data of squint sliding spotlight mode efficiently. The processing flow of the algorithm is described in detail, and compared with the conventional two-step processing algorithm. Finally, experiments on simulated and real data validate the effectiveness of the proposed algorithm in squint sliding spotlight case.