时空变背景电离层对GEO TomoSAR成像影响分析  

Impacts of Temporal-Spatial Variant Background Ionosphere on Geosynchronous SAR Tomography

作　　者：张彬 董锡超[1] 胡程[1,2] Zhang Bin;Dong Xichao;Hu Cheng(Radar Research Lab, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China;Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute of Technology),Ministry of Education, Beijing 100081, 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]卫星导航电子信息技术教育部重点实验室(北京理工大学),北京100081

出　　处：《信号处理》2019年第6期1018-1024,共7页Journal of Signal Processing

基　　金：高等学校学科创新引智基地111(B14010);国家重大科研仪器研制项目(61427802);国家自然科学基金(61471038,61501032);北京市自然科学基金(4162052)

摘　　要：地球同步轨道合成孔径雷达层析成像(GEOTomoSAR)是一种将地球同步轨道SAR(GEOSAR)与三维层析成像相结合的技术,它能够克服低轨SAR层析成像中重访时间长、时间去相干严重等缺点,实现对地面场景及时、精确地三维重建。但是由于GEOSAR轨道高,信号能够穿过整个电离层,使得GEOSAR信号时延长,引入严重的相位误差,进而影响GEOTomoSAR三维成像的精度。本文主要从背景电离层对雷达信号传播的影响机理出发,建立了时空变背景电离层影响下的GEOTomoSAR信号模型,进而分析了对三维成像的影响。经过分析,时空变背景电离层对GEOTomoSAR系统的影响主要包括成像目标的相对位置偏移以及高度向成像散焦。最后,通过计算机仿真验证了理论分析的正确性。Geosynchronous SAR tomography (GEO TomoSAR) is a technique that combines geosynchronous SAR (GEO SAR) with SAR tomography. It can overcome the shortcomings of long revisit time and serious decorrelation in low Earth orbit SAR tomography, and realize timely and accurate three-dimensional reconstruction of targets. However, due to the high orbit of GEO SAR, the signal can pass through the entire ionosphere, causing the signal to have a long time delay. Signal delay introduces the error phase, which in turn affects the accuracy of GEO TomoSAR 3D imaging. In this paper, based on the influence mechanism of background ionosphere on radar signals, the GEO TomoSAR signal model under the influence of temporal-spatial variant background ionosphere is established, and its influence on three-dimensional imaging is analyzed. After analysis, the influence of the background ionosphere on the GEO TomoSAR system mainly includes the relative offset of the scattering target and the imaging defocus in the elevation direction. Finally, the correctness of theoretical analysis is verified by computer simulation.

关 键 词：背景电离层 时空变 地球同步轨道SAR 层析成像 

分 类 号：TN959.74[电子电信—信号与信息处理]