广播电离层模型精度评估分析

Accuracy evaluation of broadcast ionosphere model

全球定位系统(GPS)、北斗卫星导航系统(BDS)和伽利略卫星导航系统(Galileo)均在导航电文中发播电离层模型参数供用户改正电离层延迟。由于采用不同的电离层模型,性能也不同。全面地分析了不同电离层模型的差异及对标准定位的影响。采用欧洲定轨中心(CODE)的全球格网电离层产品作为参考值,对在全球范围内不同时段不同电离层模型的性能进行分析,同时分析了不同模型对定位的影响。结果表明,北斗全球电离层延迟改正模型(BDGIM)与CODE的全球电离层格网图最接近。内·奎克·格(NeQuickG)模型在高纬度电离层延迟误差均方根(RMS)值为1.7个总电子含量单位(TECU),低纬度电离层延迟误差RMS值为5.6个TECU;GPS克洛布彻(Klobuchar)电离层模型(GPSKlob)在低纬度时,电离层延迟误差RMS值为3.8个TECU,高纬度电离层延迟误差RMS值为6.8个TECU。BDS克洛布彻(Klobuchar)模型(BDSKlob)在中低纬度地区时,其电离层延迟误差RMS值优于5个TECU。BDGIM模型与CODE电离层产品定位精度相当,全球定位精度基本优于1.6 m,BDSKlob模型和GPSKlob模型在中低纬度区域的定位精度优于1.8 m。

Global Positioning System(GPS),BeiDou navigation satellite System(BDS)and Galileo navigation satellite system(Galileo)both broadcast different ionosphere models for the correction of ionospheric delay.The performance of different ionospheric models is concerned by users.This paper comprehensively analyze the differences and evaluate the accuracy of different ionospheric models.The global grid ionospheric product of European Orbit Determination Center(CODE)is taken as reference to evaluate the accuracy of different models on global scale in different time periods.Finally,the influence of these models on single point positioning results are analyzed.The results show that the performance of BeiDou Global Ionospheric delay correction Model(BDGIM)is agreed very well with the precision of ionospheric grid map of CODE.The Root Mean Square(RMS)of ionospheric correction error with Galileo NeQuickG is 1.7 Total Electron Content Units(TECU)in high latitude and 5.6 TECU in low latitude.The same index of GPS Klobuchar ionospheric model is 6.8 TECU in high latitude and 3.8 TECU in low latitude.The RMS of BDS Klobuchar model in middle and low latitudes are better than 5 TECU.As far as the impact on positioning accuracy concerned,the positioning accuracy with BDGIM model of BDS on global scale is basically better than 1.6 m and that of BDS Klobuchar model and GPS Klobuchar model are both better than 1.8 m in middle and low latitudes.