一种应用于斜视聚束模式的改进极坐标格式成像算法

极坐标格式算法(Polar Format Algorithm, PFA)通常应用于正侧视聚束SAR成像，当PFA应用斜视聚束时，传统沿视线插值(Line Of Sight Interpolation, LOSI)PFA方法会导致方位频谱非等间隔采样。该文针对上述问题提出一种新的方位频谱插值方法，根据斜视聚束的几何模型可以得到方位频谱精确的插值形式，从而实现对方位频谱等间隔重采样。在获得了均匀的频谱后进行2维逆傅里叶变换，便可以得到大范围的斜视聚束场景。为了验证该文算法的有效性，进行了实验仿真及实测数据验证，该方法与传统插值的方法进行比较，能够增大斜视聚束场景范围。

A Modified Polar Format Algorithm Applied to Squinted Spotlight SAR Imaging

For broadside spotlight Synthetic Aperture Radar (SAR) imaging, Polar Format Algorithm (PFA) is applied widely as a kind of general interpolation algorithm. When PFA is applied to the squinted spotlight, coordinate rotation causes azimuth spectrum uniformly resampled. A new method of interpolation for azimuth spectrum is proposed in this paper and the accurate form of azimuth spectrum interpolation is given according to the geometry of squinted spotlight. Azimuth spectrum is resampled according to the accurate form of interpolation and uniform azimuth spectrum is obtained. Then, two-dimension IFFT is implemented and high resolution squinted spotlight image is obtained. In order to validate the effectiveness, simulation and real data are processed by the proposed method. Compared with traditional interpolation method, the scope of well-focused image is increased.