基于SAR参数化稀疏成像模型的延展目标多径抑制方法  

Multipath Ghost Suppression of Extended Targets Based on SAR Parametric Sparse Imaging Model

作　　者：袁跳跳 王岩 匡辉[4] 汪子文 丁泽刚 YUAN Tiaotiao;WANG Yan;KUANG Hui;WANG Ziwen;DING Zegang(Radar Research Lab,School of Information and Electronics,Beijing Institute of Technology,Beijing 100081,China;Yangtze Delta Region Academy of Beijing Institute of Technology,Jiaxing,Zhejiang 314019,China;Beijing Institute of Technology Chongqing Innovation Center,Chongqing 401120,China;Institute of Remote Sensing Satellite,China Academy of Space Technology,Beijing 100094,China)

机构地区：[1]北京理工大学信息与电子学院雷达技术研究所,北京100081 [2]北京理工大学长三角研究院(嘉兴),浙江嘉兴314019 [3]北京理工大学重庆创新中心,重庆401120 [4]中国空间技术研究院遥感卫星总体部,北京100094

出　　处：《信号处理》2023年第9期1596-1607,共12页Journal of Signal Processing

基　　金：国家自然科学基金项目(62271053,61971042,62101554);北京市科技新星项目(20220484109);重庆市自然基金项目(cstc2020jcyj-msxmX0663)。

摘　　要：合成孔径雷达(SAR)与传统光学传感器不同,其利用主动发射电磁波和接收电磁波技术来获取目标区域的二维图像。在实际场景(特别是城区场景)成像中,存在大量直线型延展目标,如建筑物的边缘、桥梁等,且SAR的回波信号中不仅含有电磁波经过目标返回的直接回波,还包括电磁波经过目标与环境背景(地面、水面等)多次反射的干扰回波(即“多径效应”),造成SAR成像中存在多径“鬼影”。现阶段多径抑制方法大多基于点目标模型,难以解决实际场景中由直线型延展目标与环境背景产生的多径鬼影问题。因此,本文提出了基于SAR参数化稀疏成像模型的延展目标多径抑制方法,在稀疏目标与环境背景产生多径效应的情况下,能够实现对直线型延展目标的高质量成像。首先,基于不同回波路径下目标的散射模型,建立了延展目标多径观测模型,有效描述了不同回波路径下点目标与线目标散射特性;然后,采用交替方向乘子法(ADMM)对上述延展目标多径观测模型中不同回波路径下目标的散射系数向量进行了精确估计;最后,基于上述估计结果,提出不同回波路径下的图像重构方法,将各条回波路径的能量都集中到真实目标区域,实现了直线型延展目标的高质量成像。高精度电磁计算数据验证了本文所提方法的有效性。Synthetic Aperture Radar(SAR)is an active remote sensing technology that acquires two-dimensional images of a target area by transmitting and receiving electromagnetic waves.In practical scenarios,particularly in urban areas,there are a large number of extended targets such as building liner edges and bridge liner structures.SAR receives signals that not only include the direct reflection of electromagnetic waves from the target but also interference echoes from mul⁃tiple reflections between the target and the environment background(such as ground or water),known as the“multipath effect”.This effect causes“ghosting”in SAR imaging.Most current multipath suppression methods are based on the point target model,which is challenging to apply effectively to solve the ghosting problem caused by extended targets.There⁃fore,this paper proposed a multipath ghost suppression of extended targets based on SAR parametric sparse imaging model,which can achieve high-quality imaging of straight linear extended targets in the presence of multipath effects caused by the sparse targets and environmental background.Firstly,a multipath observation model for extended targets was established based on the target’s scattering model under different echo paths,which can describe the scattering char⁃acteristics of point and extended targets under different echo paths.Secondly,the alternating direction method of multipli⁃ers(ADMM)was used to estimate accurately the scattering coefficient vectors of the target under different echo paths in the multipath observation model of extended targets.Finally,an image reconstruction method was proposed for different echo paths based on the estimated results,which can concentrate the energy of each echo path in the real target area and achieve high-quality imaging of straight linear extended targets.The effectiveness of the proposed method was verified through high-precision electromagnetic simulation data.

关 键 词：合成孔径雷达 多径抑制 延展目标 稀疏成像 

分 类 号：TN959.3[电子电信—信号与信息处理]