GNSS多系统组合PPP解算方法与成果分析

研究GPS、GLONASS和BDS三系统组合精密单点定位（PPP），包括函数模型、对流层延迟参数和差分码偏差(DCB)参数的解算方法。利用C++语言编制3系统组合PPP程序，分析MEGX网12个连续跟踪站1周观测数据，结果表明，无电离层组合模型和非组合模型的收敛速度和定位精度相当，同一测站在不同时间的收敛速度无明显差异，但非组合模型采用先验电离层信息约束可提高定位的收敛速度。多系统组合定位能改善PDOP值，提高收敛速度和定位精度；3系统组合PPP的水平坐标精度约3 cm，高程精度约5 cm，优于3个系统单独定位或2个系统组合定位的精度；当卫星遮挡较大时，多系统PPP结果较单系统更为稳定。

Processing Method and Result Analysis of GNSS Multi-System Combined Precise Point Positioning

This paper analyzes the precise point positioning method of GPS, GLONASS and BDS three-system combination, including function model, estimation methods for tropospheric delay and differential code bias (DCB) parameters. The precise point positioning program based on three-system combination is developed using C++ language, and the measurements of 12 consecutive tracking stations of MEGX network are analyzed. The results show that the convergence rate and positioning accuracy of the ionospheric combination model and the non-combined model are similar and the convergence rate at the same station on different days is not significantly different. However, the non-combined model uses a priori ionospheric constraints can improve the convergence rate. Multi-system combination can reduce the PDOP value, thus improving the convergence rate and positioning accuracy. By using three-system precise point positioning, the horizontal accuracy is about 3 cm, elevation accuracy is about 5 cm. These results are better than those of three systems alone positioning or two systems combined positioning. When the cut-off elevation angle is large, the multi-system precise point positioning has higher stability than the single system.