基于改进极坐标格式算法的大斜视SAR成像方法

针对大斜视合成孔径雷达成像（SAR）模式下，回波存在较大的距离走动和严重的距离 方位交叉耦合等问题，对传统极坐标格式算法（PFA）进行改进，提出了一种基于改进的PFA算法的大斜视SAR成像方法。根据实际回波数据存储的形式，建立了大斜视SAR的斜距模型，通过对距离向与方位向的二维泰勒级数展开设计了一种斜距平面的二维插值函数，有效地提高了成像算法的聚焦深度。与传统PFA不同，斜距平面的距离展开能够避免回波数据的投影，所以改进的算法更适用于地形起伏不平的成像场景。仿真数据和实测数据分析验证了该方法的有效性。

A Modified Polar Format Algorithm for Highly Squinted SAR

Aimed at the problems that large range migration and severe range azimuth cross coupling remain in returning echo under condition of the highly squinted synthetic aperture radar imaging (SAR) mode, the conventional polar format algorithm (CPFA) is modified and a method for highly squinted SAR is proposed. According to the actual echo data storage form, the algorithm establishes a slanted data model of the highly squinted SAR, and designs a two dimensional interpolating function of the slant range plane through the expansion of the two dimensional Taylor series in the range and azimuth directions, effectively improving the depth of focus. Moreover, the modified polar format algorithm (MPFA) is more suitable for the undulating terrain because the projection of real data onto ground plane performed in CPFA is avoided. The simulation and real data experiments show that the proposed approach is valid.