一种实验室合成孔径雷达对目标散射的成像试验

Laboratory experiments for target scattering and imaging using fully polarimetric FMCW radar system

基于实验室微波暗室构建的多极化雷达移动平台,在实验室内模拟合成孔径雷达(Synthetic Aperture Radar,SAR)对目标模型的散射成像.雷达系统发射线性调频连续波,通过基于分数Fourier变换(Fractional Fourier Transform,FRFT)的SAR成像算法处理,在距离向和方位向分别进行快速傅里叶变换(Fast FourierTransform,FFT)和特定阶次的FRFT,把回波信号在两个方向上同时近似地压缩为脉冲函数.系统以匀速平移雷达可以不同入射角正侧视一坦克模型目标,获得全极化SAR成像,并采用三面体角反射器进行散射截面的定标.进一步地,用FEKO数值仿真软件验证了散射成像的实验结果.

A fully polarimetric synthetic aperture radar （SAR） system with moving platform is constructed for experimental measurement and imaging of target scatter ing in an anechoic chamber of the Laboratory. This system operates the frequency modulated continuous wave （FMCW）. Using the fractional Fourier transform （FR FT）, the radar echoes can be turned to chirp signal in both range and azimuth direc- tions via FFT and optimal order FRFT, respectively, and compressed to an impulse function. The experiments show polarimetric scattering images from a tank-like model under different incident angles, which is calibrated by RCS of tri-angular re- flector. Numerical FEKO software is also applied to validation of scattering and im aging results.