考虑电离层对GEOSAR影响的改进CS成像算法  

CS Imaging Method for Geosynchronous SAR Considering Ionospheric Effects

作　　者：王卓群 李亚军 李雁斌 顾网平 李芬 WANG Zhuoqun;LI Yajun;LI Yanbin;GU Wangping;LI Fen(Shanghai Radio Equipment Research Institute,Shanghai 201109,China)

机构地区：[1]上海无线电设备研究所,上海201109

出　　处：《上海航天》2018年第6期98-102,共5页Aerospace Shanghai

基　　金：国家自然科学基金(61701309);上海市自然科学基金(17ZR1428800)

摘　　要：地球同步轨道合成孔径雷达(GEOSAR)轨道位置高且合成孔径时间较长,电离层的空时变化特性严重影响该雷达的聚焦性能。为解决电离层对GEOSAR成像聚焦性能的影响,提出一种改进的chirp scaling (CS)成像算法。结合GEOSAR的轨道运动特点,给出因电离层空时变化引起的回波信号模型,提出了改进CS成像算法用以解决电离层对成像聚焦性能的影响。仿真结果表明:该成像方法能较好地处理电离层影响,可获得理想的聚焦成像结果。该方法为GEOSAR实现高精度成像提供了技术支撑。Geosynchronous synthetic aperture radar(GEOSAR)has high orbital altitude and long synthetic aperture time.However,the key problem in GEOSAR imaging process is that ionospheric effects will result in the defocusing with the classical imaging algorithm.This paper proposes a new chirp scaling(CS)imaging algorithm.Firstly,based on the orbital motion characteristics of GEOSAR,the echo signal model based on ionospheric space-time variation is given.Then,an improved CS imaging algorithm is proposed to solve the influence of ionosphere on imaging focusing performance.Finally,the imaging simulations for the point targets are implemented.The imaging results show the correctness and effectiveness of the new imaging technique in solving ionospheric effects.This method provides technical support for high-precision imaging of GEOSAR.

关 键 词：地球同步轨道合成孔径雷达 CS成像算法 电离层影响 合成孔径时间 聚焦性能 

分 类 号：P412.25[天文地球—大气科学及气象学]