Real-time global ionospheric corrections have been provided by several ionospheric analysis centers of the Internation-al GNSS Service(IGS)since 2017.Considering the potential unstable ionospheric streams from individual analysis centers in real applications,we propose a sliding window based differential slant total electron content(dSTEC)weighting technique for the combination of real-time global ionospheric maps(RT-GIMs).The combined RT-GIMs are generated using real-time iono-spheric streams from the Chinese Academy of Sciences(CAS),Centre National d'Etudes Spatiales(CNES),Polytechnic Uni-versity of Catalonia(UPC)and Wuhan University(WHU).The performance of combined RT-GIMs is validated during 15 February and 15 March 2022 in both ionospheric correction and positioning domains.The root mean square(RMS)differences between combined RT-GIM and IGS-GIM are 3.30 TECU for our combined one,and 3.20 TECU for UPC combined one.The positioning performance of combined RT-GIMs is also evaluated in ionospheric corrected single-frequency standard point posi-tioning(SF-SPP)and ionospheric constricted single-frequency precise point positioning(SF-PPP),by analyzing the 95％quan-tile of positioning residuals.Compared to IGS-GIM corrected results,the positioning accuracy of combined RT-GIMs decreases by 7.7％and 4.9％in SF-SPP and SF-PPP analysis,respectively.Compared to BDGIM corrected results,the positioning ac-curacy of combined RT-GIMs increases by 15.9％in SF-SPP and 9.5％in SF-PPP,respectively.CAS combined RT-GIMs have been routinely provided to the IGS since 2022.
关键词
实时全球电离层地图/差分斜向总电子含量/滑动窗口/实时综合/实时服务
Key words
real-time global ionospheric map/differential slant total electron content/sliding window/real-time combination/real-time service
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