Performance evaluation of atmospheric precipitable water vapor inversion of mutil-system GNSS at selected MGEX stations

In June 2020, the BeiDou Navigation Satellite System (BDS) completed its global coverage deployment. In order to analyze the accuracy of BDS derived water vapor information, the observed data of 15 MGEX stations in October and November 2021 were used to invert carry out water vapor. The well-known comprehensive GNSS data processing software package GAMIT was used to calculate the observation data of BDS, GPS, Galileo and GLONASS respectively, and the tropospheric zenith total delay (ZTD) was compared with the results provided by IGS, and the PWV was compared with the PWV derived from radiosonde and ERA5 data. Results show that when cutoff angle is set to 5°, the root mean square (RMS) of the ZTD estimated by four satellite systems are all less than 13 mm. Compared with RS-PWV, GPS-PWV, BDS-PWV, Galileo-PWV and GLONASS-PWV, the mean RMSs are 2.25 mm, 2.46 mm, 2.52 mm and 2.84 mm, respectively, all RMSs are less than 3 mm. Compared with ERA5-PWV, the mean RMSs are 1.63 mm, 1.86 mm, 1.76 mm and 1.99 mm, respectively, all RMSs are less than 2 mm. GPS has the highest water vapor determination accuracy, while BDS’s accuracy of water vapor detection is lower than that of GPS and Galileo, but higher than GLONASS, which can meet the requirements of meteorological applications.