空间目标成像中基于FrFT的高精度距离压缩方法

针对星载雷达空间目标成像遇到的距离向回波调制问题,通过对星载平台下空间高速平稳目标运动特性的分析,提出基于分数阶傅里叶变换(fractional Fourier transform, FrFT)和多项式拟合的高精度距离向压缩方法。该方法利用FrFT对空间目标的部分解调回波进行距离向压缩,并结合多项式拟合迭代获取随方位时间变化的径向速度,为距离向压缩提供精确的分数阶旋转角。与传统逆合成孔径雷达(inverse synthetic aperture radar,ISAR)距离向压缩方法相比,该方法能够实现高精度距离向压缩,从而提高成像质量。仿真实验验证了该方法的有效性。

High precision range compression based on FrFT for space target imaging

This paper focuses on the range echo modulation for the space target imaging on the space-borne radar. A range compression algorithm of high precision is proposed through analysis on relationship between the high-speed stationary target and the space-borne radar, which uses the fractional Fourier transform (FrFT) and polynomial fitting. FrFT is applied to implement the range compression of some de-chirped echoes and polynomial fitting is utilized to acquire the radial velocity varying with the slow-time. Accordingly the precise rotation angel is obtained for range compression. Compared with the traditional inverse synthetic aperture radar (ISAR) range compression method, the proposed algorithm accomplishes the range compression with high precision, and enhances the quality of imaging. The numeric simulations testify the feasibility of the algorithm.