GNSS全球广播电离层模型精度分析

单频用户主要采用全球导航卫星系统(global navigation satellite system,GNSS)广播电离层模型来修正电离层延迟,GPS、Galileo和BDS-2均播发广播电离层参数。BDS-3试验卫星也播发了应用于全球电离层延迟修正的BDGIM(BeiDou global ionospheric delay correction model)模型参数。以国际GNSS服务(International GNSS Service,IGS) GIM (global ionosphere maps)产品和全球140余个GNSS观测站GPS双频观测量为基准,从全球范围、不同纬度、不同区域等系统分析了GPS、Galileo和BDS-3的全球广播电离层模型改正精度,并与IGS预报电离层产品(IGS P1和IGS P2)进行比较。分析认为,IGS P1和IGS P2产品的改正精度总体最优,BDGIM参数优于Gal NeQuick和GPS K8。对于BDS-3新发布的BDGIM参数,分析认为,在全球范围的改正精度(均方根)约为3.58 TECU,改正率约77.2%,在全球不同区域的改正精度相当。

Accuracy Analysis of GNSS Global Broadcast Ionospheric Model

Global navigation satellite system(GNSS) broadcast ionospheric model is the main method for single frequency users to correct ionospheric delay. GPS, Galileo and BDS-2 satellites all broadcast ionospheric parameters. The BDS-3 test satellites broadcast the BDGIM’ s(BeiDou global ionospheric delay correction model) parameters, using to correct the global ionospheric delay. Using the International GNSS Service(IGS) GIM(global ionosphere maps) products and the GPS dual-frequency observations from more than 140 GNSS observation stations around the world, the correction accuracies of global broadcast ionosphere model of GPS, Galileo and BDS-3 are analyzed in the global range, different latitudes and different regions. The models are compared with the ionosphere model of IGS prediction(IGS P1 and IGS P2) as well. The results show that the correction accuracy of IGS P1 and IGS P2 products is generally optimal,and BDGIM’s parameters are better than Gal NeQuick and GPS K8. For the newly released BDGIM’s parameters of BDS-3, the correction accuracy(i.e. root mean square, RMS) is about 3.58 TECU in the global scope, and the correction rate is about 77.2%, with the same correction accuracy in different regions of the world.