A coordinate-transform based FFBP algorithm for high-resolution spotlight SAR imaging

This paper proposes a coordinate-transform (CT) implementation for the fast factorized backprojection (FFBP) algorithm (CT-FFBP) to process high-resolution spotlight synthetic aperture radar (SAR) data. Unlike the FFBP utilizing two-dimensional image-domain interpolation for sub-aperture fusion, CT-FFBP finishes the image-projection using CT with the accommodation of chirp-z transform and circular shifting. Without interpolation, CT-FFBP yields enhanced efficiency over the interpolation based FFBP, besides maintaining high precision simultaneously. Both simulation and real-data experiments verifies the efficiency and precision superiorities of the CT-FFBP.摘要创新点文章提出了一种基于坐标转化的快速分级后向投影算法, 该算法可用于高分辨率聚束合成孔径雷达成像。 与经典的基于二维图像域插值的快速后投影算法不同, 该算法利用坐标转化实现图像在不同局部极坐标系之间的投影, 进而相干叠加逐级提升分辨率, 坐标转化通过平移和chirp-z伸缩实现。 由于避免了插值操作, 与经典快速后投影算法相比该算法提升了运算效率, 同时保证高精度成像。 文中最后分别通过仿真实验和实测数据实验验证了算法的高效率和高精度。