基于GPS-R的双基地SAR移动目标成像方法研究  

Bistatic SAR moving target imaging algorithm study based on GPS-R signal

作　　者：何振宇 杨扬[1,2] 陈武 翁多杰[1,2] HE Zhenyu;YANG Yang;CHEN Wu;WENG Duojie(Department of Land Surveying and Geo-Informatics,Hong Kong Polytechnic University,Hong Kong 999077,China;Shenzhen Research Institute,Hong Kong Polytechnic University,Shenzhen 518057,China;School of Computer and Information,Hohai University,Nanjing 211100,China)

机构地区：[1]香港理工大学土地测量及地理资讯学系,中国香港999077 [2]香港理工大学深圳研究院,深圳518057 [3]河海大学计算机与信息学院,南京211100

出　　处：《遥感学报》2022年第12期2555-2567,共13页NATIONAL REMOTE SENSING BULLETIN

基　　金：国家重点研发计划(编号:2016YFB0502101);深圳市科技创新委基础研究(编号:JCYJ20170818104822282);香港研究资助局研究用途补助金(编号:PolyU 152151/17E)。

摘　　要：全球导航卫星系统反射GNSS-R (Global Navigation Satellite System Reflectometry)用做双基地合成孔径雷达(简称GNSS-SAR)是近年来新兴的研究方向。当前GNSS-SAR成像的主要对象是地表静态目标,关于动目标成像的研究非常少。本文以全球定位系统GPS (Global Positioning System)卫星作为照射源,提出一种动目标成像方法。该方法首先构建了成像场景的双基地几何模型,推导了一种近似的双基地距离历程,用于描述目标回波的方位向相位变化,然后,采用Keystone变换校正由目标运动引起的未知距离单元徙动;组合短时傅里叶变换和随机抽样一致性算法估计未知的目标移动速度,最后,推导了方位向匹配滤波器用于方位向压缩从而完成动目标成像。采集了两组现场实验数据验证本文方法,实验结果表明:提出的算法能够有效地成像移动目标并且准确地估计目标运动速度、船长度、离岸垂直距离以及移动方向。Global navigation satellite system reflectometry(GNSS-R) is a typical fusion application of the remote sensing and navigation technology and has become a potential research direction.The use of GNSS-R for constructing a passive bistatic synthetic aperture radar(called as GNSS-SAR) has drawn great attention from the research community in recent years.Current investigations on GNSS-SAR focus on the static objects on land.However,few contributions to the moving target imaging can be found in this novel field.Imaging moving target is a long-standing subject for modern SAR systems.However,traditional GNSS-SAR image formation algorithms cannot be directly applied to the moving target due to the unknown motion.Accordingly,the moving target will be smeared and shifted in the static SAR image.To extend the application of GNSS-SAR,this work selects the global positioning system satellite as the illuminator of opportunity and proposes a frequency domain-based moving target image formation algorithm that has a higher processing efficiency than the traditional time domain-based GNSS-SAR algorithm.To image a moving target,frequency domain-based algorithm should solve three main problems:(1) The unknown range cell migration induced by the moving target should be corrected.(2) The velocity of the moving target should be estimated.(3) The azimuth compression derivation should be performed due to the bistatic acquisition geometry.To deal with the main problems,this work selects maritime moving ships as the targets of interest and constructs a bistatic acquisition geometry where the receiver and the satellite are stationary during the observation time.Meanwhile,the trajectory of the moving target perpendicular to the line of sight of the receiver antenna is used as a synthetic aperture.An approximate bistatic range history is first deduced to describe the azimuthal phase variation of the target signal based on the bistatic acquisition geometry.A keystone transform is then employed to address the unknown range cell migration,and a m

关 键 词：GNSS-R GNSS-SAR 动目标成像 KEYSTONE变换 短时傅里叶变换 随机抽样一致性算法 

分 类 号：P2[天文地球—测绘科学与技术]