多系统双频精密单点定位不同模型下性能比较分析

通过2018年1月多全球卫星导航系统（GNSS）实验(MGEX)的十个测站数据,采用无电离层模型和非差非组合模型,对单系统、双系统和四系统精密单点定位（PPP）进行定位性能分析,定位性能包括收敛时间和定位精度. 实验结果表明,两种PPP模型定位性能相当,但优于单频PPP,在E、N和U方向收敛时间缩短20 min左右,定位精度提高1.6 cm左右;联合多系统能够增加卫星数,改善卫星间几何构型,提升PPP的定位性能. 对GLONASS伪距频间偏差（IFB）采用估计每颗GLONASS卫星的伪距IFB模型和伪距IFB为频率二次多项式模型提升PPP的定位性能,结果表明估计每颗GLONASS卫星的伪距IFB模型要优于伪距IFB为频率二次多项式模型,估计伪距IFB相比忽略伪距IFB在PPP定位性能上有不同程度的提升. 

Performance comparison of multi-GNSS and dual-frequency PPP under different models

With the data of BDS, GPS, Galileo and GLONASS of ten stations in MGEX in January 2018, the ionosphere-free model and the un-differenced and uncombined model are used to analyze the positioning performance of PPP in single-system, dual-system and four-system. The positioning performance analyzed in this paper includes convergence time and positioning accuracy. The experimental results show that the positioning performance of the two PPP models is equivalent, and they are better than the single-frequency PPP. The convergence time in the E, N, and U directions is shortened at about 20 minutes, and the positioning accuracy is improved at about 1.6 cm. Multi-GNSS can increase number of satellites, and improve inter-satellite geometry and? positioning performance of PPP. The GLONASS pseudorange IFB is estimated to use the pseudorange IFB model and the pseudorange IFB of each GLONASS satellite as the frequency quadratic polynomial model. The results show that the pseudorange IFB model of each GLONASS satellite is better than the pseudorange IFB for the frequency quadratic polynomial model. The two model of pseudorange IFB estimation have certain degree of improvement in PPP positioning performance compared to that ignoring the pseudorange IFB.