基于MFT的非匀速转动目标干涉ISAR三维成像方法

A 3-D InISAR Imaging Method For Non-Uniformly Rotating Target Based on Match Fourier Transform

非匀速转动目标各距离单元内的回波信号为多分量的多项式相位信号,采用傅里叶变换进行横向压缩得到的目标ISAR像会发生散焦,从而影响干涉ISAR三维成像质量。针对非匀速转动目标,提出了一种基于匹配傅里叶变换的InISAR三维成像方法。该方法对各天线接收回波的每个距离单元采用匹配傅里叶变换得到聚焦的目标ISAR像,进而得到散射点不同接收天线间的干涉相位,最后从干涉相位求解散射点三维位置重构目标的三维图像。由于非匀速转动目标多项式相位信号的相位系数之间的比值只与目标转动参数有关,因此该方法只需估计某一个散射点对应回波的多项式相位系数就可构造所有匹配傅里叶变换的积分路径,而且适用于任意阶的非匀速转动目标。仿真表明了该方法的有效性。

The echo in each range cell of non-uniformly rotating target is multi-component polynomial phase signal. When Fourier Transform （FT） is used for cross-range compressing, the Inverse Synthesis Aperture Radar （1SAR） image of non-uniformly rotating target will be defocused, thus affecting the 3-dimetional imaging quality of Interferometric ISAR （InlSAR）. A method based on Match Fourier Transform （MFT） is proposed for non-uniformly rotating target InlSAR 3- dimetional imaging. In this method, MFT is used for cross-range compressing of three interferometric antennas＇ received echoes to obtain focused ISAR images. Then the 3-directional distribution of target scattering points can be obtained through the interferometry of focused ISAR images. Because the phase coefficient ratios of non-uniformly rotating target＇ s polynomial phase signal are determined by the target ＇ s rotation parameters completely. It＇ s only need to estimate the phase coefficient ratios of one scattering point＇ s echo to construct the integration path of MFT by this method. It can be adapted to the 3-dimetional InlSAR imaging of any order non-uniformly rotating target. The validity of this method is demonstrated by simulation data.