基于分数阶傅里叶变换的ISAR横向定标

逆合成孔径雷达的横向定标是确定横向像素代表的真实尺寸、进行目标几何特征提取的前提。本文研究了一种基于分数阶傅里叶变换（Fractional Fourier transform，FrFT）的横向定标方法，利用回波信号在慢时间域为线性调频信号的特性，使用FrFT方法得到信号在不同分数阶傅里叶域的能量聚集性，估计目标回波信号多普勒调频率，求得转动角速度，进而完成横向定标。仿真实验验证了算法的有效性和准确性。

Cross-Range Scaling of ISAR Based on FrFT

Cross-range scaling of the inverse synthetic aperture radar (ISAR) determines the real size of one cross-range unit, by which the geometry character of the target can be obtained. Considering the linear frequency modulation of the echo signal in slow-time domain, a new approach based on fractional Fourier transform (FrFT) is proposed for cross-range scaling. The approach estimates the chirp rate of the Doppler history and the target rotation vector according to the energy concentration property of the signal in the different fractional Fourier domain. The simulation results show that the algorithm is effective and accurate.