斜视FMCW-SAR的四阶多项式插值波数域算法

A Wavenumber Domain Algorithm Using Four-order Polynomial Interpolation for Squint FMCW-SAR

FMCW-SAR因其体积小、重量轻、成本低和高分辨率等优点近年来发展迅速,在低成本的民事应用领域具有广阔的发展前景。FMCW-SAR频率变标算法及其改进算法对距离-方位耦合相位项作了三阶近似,忽略二次和三次项的距离空变性,只能适用于窄测绘宽度、侧视及小斜视角情况。对中大斜视工作,文中提出了采用四阶多项式插值的波数域算法,给出了斜视下的距离徙动因子,考虑了二次距离压缩项的空变性和四次耦合项。利用典型参数,通过不同斜视角下误差相位的分析和点目标成像的仿真实验验证了所提算法的合理性和有效性。

Recently FMCW-SAR develops rapidly because of its small size,light weight,inexpensive and high-resolution,and has great prospects in the cost-effective civil applications.The frequency scaling algorithm and its modified ones which neglect the thind-and higher-order range-azimuth coupling terms and the range dependence of the secondary range compression are suitable for imaging a relatively small area in the broadside and low-squint configuration.In the medium-high-squint configuration a wavenumber domain algorithm using the four-order polynomial interpolation is proposed.The range migration factor is updated for the squint configuration and the range variation of the secondary range compression is taken into account.The rationality and effectiveness of the presented algorithm are verified by the simulation,using typical parameters,of the phase error and point targets with different squint angles.