一种基于广域高分 SAR／GMTI 系统的高精度径向速度估计方法

摘要

方位向多通道广域高分合成孔径雷达运动目标指示（SAR／GMTI）系统的各通道回波存在多普勒模糊，参数估计时会出现严重的速度模糊。针对这一问题，本文提出了一种高精度无模糊径向速度估计方法。首先利用动目标 Chirp 傅里叶变换（CFT）后的空时谱在空间维度上无模糊的特点，在空域自适应滤波时避免了动目标模糊分量的影响，降低了算法所需通道数目；然后分别使用谱估计和 Radon 变换的方法估计基带径向速度和模糊数，最终得到高精度无模糊的径向速度。仿真结果验证了当待检测距离单元内存在多个运动目标时该方法的有效性。%For the multichannel synthetic aperture radar ground moving target indication system with the capability of high resolution wide swath imaging (HRWS SAR/GMTI),the echoes of each channel suffer from Doppler frequency ambiguity, which leads to sever velocity ambiguity during parameter estimation.Concerning this issue,a high-accuracy unambiguous estimation method of radial velocity is proposed.Firstly,since the space-time spectrum of moving targets echoes is unam-biguous in space dimension after chirp Fourier Transform (CFT),it avoids the influence of ambiguous components while adaptive filtering in space domain,thereby reducing the number of necessary channels.Afterwards,to obtain the high ac-curacy unambiguous radial velocity,the spectrum estimation and Radon Transformation are employed to estimate the base-band radial velocity and ambiguity number separately.With regard to the scene that there are several moving targets emerge from one range bin,some simulation experiments are taken to demonstrate that the proposed algorithms is highly effective.