北斗电离层模型精度分析

Accuracy Analysis of Beidou Ionosphere Model

北斗电离层模型包括基本导航的BDSKlob模型、BDGIM模型及广域差分格网电离层模型,本文详细分析2种基本导航的电离层模型因相邻模型参数更新引起的延迟跳变,基于CODE格网电离层模型对比2种电离层模型随空间和时间的变化情况,分析不同电离层模型在不同时段不同纬度的改正精度及定位精度,并利用2018年数据对北斗格网点电离层信息的服务范围和服务精度进行评估。结果表明,相比于BDSKlob模型,BDGIM模型与CODE格网电离层模型更接近,且分布均匀,相邻2组模型参数更新的延迟跳变小于1 ns。BDGIM模型在北半球的改正精度优于南半球,在中国区域及全球范围的改正率分别达到75%及60%以上,明显优于BDSKlob模型,且BDGIM模型相比于BDSKlob模型的定位精度最多可提升45%。北斗格网电离层的有效区域基本覆盖中国范围,电离层延迟误差优于2.08 TECu,改正比例大于80%。

The Beidou ionosphere model includes the Beidou system modified Klobuchar model(BDSKlob),the Beidou global broadcast ionospheric delay correction model(BDGIM)and a wide area differential grid ionosphere model.We analyze in detail the delay jump caused by updating parameters of two ionospheric models.Based on code grid ionosphere data,we compare the changes of two ionosphere models with space and time.We analyze the correction and positioning accuracy of different ionosphere models at different latitudes in different periods.We evaluate the service scope and service accuracy of ionosphere information of Beidou grid network in 2018.The results show that,compared with the BDSKlob ionospheric model,BDGIM and CODE GIM are similar in accuracy and distribution;the delay jump of parameter updating of two adjacent models is less than 1 ns.The accuracy of BDGIM model in the northern hemisphere is better than that in the southern hemisphere.The correction rate of BDGIM in China is more than 75%,and the global correction rate is 60%,which is better than the BDSKlob ionospheric model.The positioning accuracy of BDGIM can be improved by up to 45%compared with the BDSKlob model.The effective ionosphere area of Beidou grid basically covers China,the ionosphere delay error is better than 2.08 TECu,and the correction ratio is better than 80%.