说明：  实现了SAR成像点目标仿真中中RD算法的零斜视角成像，根据洪文翻译的Ian G. Cumming的《合成孔径雷达成像算法与算法》讲解的算法实现。
(SAR imaging point target to achieve a simulation algorithm in RD zero oblique angle imaging, achieved according to Hung translation of Ian G. Cumming " synthetic aperture radar imaging algorithm and algorithm" to explain the algorithm.)