基于Radon变换的SAR地面运动目标径向速度估计

Radial velocity estimation based on Radon transforms for SAR images of moving ground targets

合成孔径雷达(SAR)地面动目标径向速度导致的Doppler模糊和频谱分裂会严重影响对其检测和速度估计的性能。为此,该文提出一种基于Radon变换(RT)的方法来高效准确地解决Doppler模糊和频谱分裂,实现Doppler中心和径向速度的准确估计。该方法首先基于雷达和平台参数计算目标可能模糊数对应的距离走动倾斜角,确定"模糊数-角度"对应关系;进而基于实测数据计算各先验角度RT值,搜索最大值获取模糊数。同时,提出了Doppler频谱检测器解决频谱分裂问题,可结合能量均衡法准确估计基带Doppler中心和目标径向速度。数值仿真试验结果证明了该方法的有效性。

With synthetic aperture radar（SAR）,the radial velocity of a moving ground target may cause Doppler ambiguities and spectrum split,which seriously affect the detection and velocity estimates.A Radon transform（RT）based method was developed to efficiently resolve the Doppler ambiguities and spectrum split to obtain precise estimates of the Doppler centroid and radial velocity.First,the inclination angles of the range walk are determined for all possible ambiguity numbers based on the radar and platform parameters to project the ambiguity number to the inclination angle.Since the radial velocity is unknown,the RT for all prior angles are computed with the ambiguity number obtained by searching for the peak value.A Doppler spectrum detector is used to solve the spectrum split and to accurately estimate the baseband Doppler centroid using the energy balance approach.Numerical simulations demonstrate the effectiveness of this method.