合成孔径雷达图像中的动目标速度联合估计

Velocity Estimation of Moving Targets in Synthetic Aperture Radar Images

为估计复数合成孔径雷达图像中动目标的速度,本文基于对称散焦滤波技术设计了联合速度估计方法。对于一个动目标雷达图像,该方法首先利用一距离向速度值在距离多普勒平面将目标的距离多普勒轨迹沿距离向对齐,然后利用一方位向速度值构建的对称散焦滤波器沿方位向将该目标图像重新聚焦,得到两个新的目标图像。通过计算这两幅散焦图像的锐度差,可建立一个以距离向速度和方位向速度为变量的锐度差曲面。在曲面的峰值或谷底处即可得到目标速度的估计值。理论分析和实验结果表明了该方法的可行性和有效性。

A joint velocity estimator is proposed to compute the velocity components of moving targets detected in complex-valued synthetic aperture radar （SAR） images based on symmetric defocusing technique. In this method, the range Doppler locus of a moving target is aligned in range direction by using a range velocity value in the range Doppler plane firstly, and then two defoeused SAR images is generated by two symmetric defocusing filters based on an azimuth velocity component value. By computing the sharpness difference between the two defocused images, a sharpness difference surface varying with two velocity component values is estab- lished. As a result, the velocity components can be estimated from the peak or valley value of the surface. Theoretical analysis and experimental results verify the practicability and effective- ness of the proposed algorithm.