GPS与北斗电离层延迟误差对比分析

Comparison of ionospheric delay accuracy between GPS and Beidou

在GPS与北斗的多系统定位中,使用双系统双频接收机,影响电离层延迟精度的主要因素是各系统导航电文中的电离层参数。由于电离层参数的不同,采用同一电离层时延模型计算得到的电离层延迟结果互不相同,造成时延精度的差异。利用GPS/北斗接收机进行观测,得到两系统的电离层参数,通过模型计算两系统在垂直方向的电离层延迟TEC,并将同一时刻、同一区域内的IGS电离层的TEC作为参考值来计算两系统的电离层时延精度。实验结果表明,GPS与北斗导航电文中的电离层参数存在较大差异,使得在同一地区、同一时刻两系统的计算结果出现较大差异,利用IGS参考值求其时延精度,GPS的电离层延迟精度较北斗系统要高。

In the compatible process of GPS and Beidou,if it uses two-system two-frequency receiver,the main factor influencing the ionospheric delay accuracy is the ionospheric parameter in each system's ephemeris.Due to the difference of the two systems' parameters,when it applies the same ionospheric delay model to acquire the ionospheric TEC,the final results will show somewhat differences. When taking the use of GPS/Beidou multi-mode receiver,it can obtain the ionospheric parameters in GPS and Beidou's ephemerides to acquire delay TEC with the ionospheric model.Then the IGS ionospheric TECin the same place and same time will be seen as the reference so that it can make contrast with GPS and Beidou's ionospheric delay accuracy.In the experiment,the parameters in the two systems' ephemerides show the significant differences so that once it use the same Klobuchar model,it will bring different TEC.When the TECresults from GPS and Beidou subtract IGS reference value,the final results show that the accuracy of GPS is higher than the Beidou's.