Evaluation of the positioning performance of multi-GNSS RT-PPP method

Abstract

The progress in precise point positioning (PPP), the advent of multi-GNSS constellation and the provision of real-time orbit, and clock products by analysis centers have increased interest in real-time precise point positioning (RT-PPP) method. Thus, various software packages have been developed for positioning with RT-PPP. In this contribution, this study is conducted to evaluate the positioning performance of RT-PPP method. For this purpose, 6 IGS RTS stations were selected in different regions that provide GPS, GLONASS, GALILEO, and BEIDOU data. For processing using BKG Ntrip Client (BNC) Software v.2.12, CLK93 and RTCM3EPH streams were used for RT Multi-GNSS orbit/clock corrections and broadcast ephemerides, respectively. RT-PPP coordinates were obtained for 4 hours at 1-s intervals by means of GPS-only, GPS+GLONASS, and GPS+GLONASS+GALILEO+BEIDOU constellation combinations. As a measure of accuracy, the derived RT-PPP coordinates were compared with the reference coordinates, obtained from the 24-hour static-PPP solutions by CSRS-PPP. The experimental results show that after the convergence time, the RT-PPP method can provide accuracy better than 5 cm and 10 cm in horizontal and vertical directions, respectively. Additionally, in comparison with GPS-only results, multi-GNSS combinations enhance the positioning accuracy in some of the stations. Besides the positioning performance of the RT-PPP method, the suitability of real-time zenith tropospheric delay (RT-ZTD) estimates was assessed by comparing them with the IGS final troposphere product (IGS-ZTD). The results illustrate that the ZTD differences are mostly less than 2 cm in three satellite configurations.