南极GPS定位中的电离层延迟分析

基于南极地区国际GNSS服务组织(IGS,International GNSS Service)跟踪站的全球定位系统(GPS,Global Position System)双频实测数据,分析了南极地区电离层延迟的变化情况及其二阶项延迟对南极GPS定位结果的影响.结果表明:南极地区的总电子含量(TEC,Total Electron Content)日间波动频繁,其日间TEC最大值变化较中纬度地区剧烈;在南极地区夏季,电离层二阶项延迟对GPS定位结果的影响可达cm级.同时,由于欧洲定轨中心(CODE,The European Center for Orbit Determination)提供的全球电离层模型(GIM,Global Ionosphere Maps)在南极区域应用的局限性,通过选取南极地区6个IGS跟踪站作为基准站建立了区域电离层TEC模型(RIM,Regional Ionosphere Model).经实测数据计算证明,对于南极地区,RIM的定位精度在一定程度上优于全球电离层模型GIM.

Ionospheric delay in the Antarctic GPS positioning

Based on the global position system(GPS) dual-frequency measured data of international GNSS service (IGS) station in Antarctic region, the variation of ionospheric delay and the impact of ionospheric second-order delay on GPS positioning was analyzed. Result shows, total electron content(TEC) in Antarctic region has frequent fluctuation during the day and the maximum TEC in the daytime changes more intensely than in the mid-latitude area. In Antarctic region, the influence of ionospheric second-order delay on GPS positioning can achieve a magnitude of cm in summer. In case of the applied limitation of global ionosphere maps(GIM) provided by the European Center for orbit determination(CODE) in the polar area, six IGS stations in Antarctic region were chosen as base stations to establish the regional ionosphere model(RIM). Results show, in Antarctic region the positioning precision of RIM is more superior than GIM to some extent.