Convergence Time Analysis of Multi-constellation Precise Point Positioning Based on iGMAS Products

摘要

This contribution focuses on the performance of multi-GNSS precise point positioning (PPP) with iGMAS products. Daily GNSS measurements from 50 stations observed during one hundred days in 2015 are used, the convergence time and positioning accuracy are investigated. As a comparison, the same processing is employed by using GBM products provided by GFZ. The results show that: (1) Compared to GPS-only PPP, multi-GNSS PPP has a great improvement in convergence time, while it is not significant for positioning accuracy. In detail, the averaged convergence time of GPS/BDS PPP is reduced by 14.6 %, and 28.86 % for GPS/GLONASS PPP; the GPS/BDS/GLONASS PPP can further decrease the convergence time, but no obvious improvement is found in four-constellation (GPS/BDS/GLONASS/GALILEO) PPP, compared with GPS/BDS/GLONASS PPP, due to the limited number of GALILEO satellites. As to the positioning accuracy, they are in the same level after the initialization. (2) Using the same observation data, the final position accuracy of both the multi-constellation PPP using iGMAS products and that using GBM products could reach millimeter level in the horizontal, while the convergence time of iGMAS products is relatively slow. Analysis of statistical results shows that the accuracy of positioning is reliable, which could further prove the stability and reliability of iGMAS products.