基于全极化SAR观测的TEC反演算法分析  

The analysis of TEC inversion algorithms based on full-polarization SAR observations

作　　者：朱艺洵 熊超 王丰珏 ZHU YiXun;XIONG Chao;WANG FengJue(Department of Space Physics,School of Electronic Information,Wuhan University,Hubei Luojia Laboratory,Wuhan 430072,China)

机构地区：[1]武汉大学电子信息学院空间物理系,湖北珞珈实验室,武汉430072

出　　处：《地球物理学报》2024年第11期4015-4029,共15页Chinese Journal of Geophysics

基　　金：湖北珞珈实验室专项基金(220100011);科技部重点研发计划(2022YFF0503700);中欧龙计划项目(59236)联合资助。

摘　　要：电离层的色散特性决定了无线电波信号穿越其传播时会产生法拉第旋转效应(Faraday Rotation,FR).基于全极化合成孔径雷达(Synthetic Aperture Radar,SAR)卫星观测可实现对法拉第旋转角(Faraday Rotation Angle,FRA)的测量,并进一步实现对电波传播路径上电离层总电子含量(Total Electron Content,TEC)的反演.为提出一种鲁棒性较强的SAR-TEC反演方法,本研究利用10组共251景PALSAR-1(Phased Array Type L-band Synthetic Aperture Radar)全极化SAR数据,对中纬度北美洲地区的FRA进行了估计,并详细对比了四种利用FRA来计算TEC的算法.为了验证计算得到的SAR-TEC的准确性,以全球卫星导航系统(Global Navigation Satellite System,GNSS)地基观测台网得到的TEC作为参考值进行对比,揭示了基于SM算法得到SAR-TEC具有最好的相关性.同时我们进一步考量了地磁场对SAR-TEC反演算法的影响,利用CHAMP(Challenging Minisatellite Payload)卫星实测的磁场数据替代由国际地磁参考场(International Geomagnetic Reference Field,IGRF)估算的磁场,进一步提升了基于SM算法得到的SAR-TEC反演精度,其与地基GNSS-TEC的相关性达到了0.97,RMSE仅为1.14 TECU.Faraday rotation(FR)occurs when radio wave signals propagate through the ionosphere due to its dispersive properties.Based on the full-polarization Synthetic Aperture Radar(SAR)satellite observation,the measurement of the Faraday rotation angle(FRA)can be achieved,and then the inversion of the total electron content(TEC)in the ionosphere along the propagation path of radio waves can be further realized.To propose a robust SAR-TEC inversion method,a total of 251 views of Phased Array Type L-band Synthetic Aperture Radar(PALSAR-1)full-polarization SAR data from 10 groups are utilized in this study to estimate the FRA over mid-latitude North America.A comprehensive comparison of four algorithms that employ FRA to estimate TEC is provided.To verify the accuracy of SAR-TEC,the TEC obtained from the ground-based Global Navigation Satellite System(GNSS)observatory network is employed as a reference value for comparison.Ultimately,the best correlation of SAR-TEC is obtained based on the SM algorithm.Furthermore,the impact of the geomagnetic field on the SAR-TEC inversion algorithm is investigated.Instead of the magnetic field estimated by the International Geomagnetic Reference Field(IGRF),the magnetic field data measured by the Challenging Minisatellite Payload(CHAMP)satellite further improves the accuracy of the SAR-TEC inversion based on the SM algorithm.Additionally,the correlation between the SAR-TEC and GNSS-TEC is strengthened,reaching 0.97 with an RMSE of only 1.14 TECU.

关 键 词：PALSAR FRA TEC IGRF CHAMP卫星 

分 类 号：P351[天文地球—空间物理学]