关键词: 大气可降水量反演, 精密单点定位, 北斗卫星导航系统, 实时卫星轨道钟差改正, 暴雨灾害短时预警

Abstract: The precision single point positioning service (PPP-B2b service) of BDS-3 sends correction information to the user through the satellite B2b signal, which is free from the dependence on external communication, and provides a new technological way for real-time inversion of precipitable water vapor (PWV) in the atmosphere. In this paper, the accuracy of PWV inversion using PPP-B2b service is analysed experimentally, and the experimental results show that the difference between the inversion results using PPP-B2b service and those using the CODE hindcast precision ephemeris product is 3.70 mm in RMS and 3.61 mm in STD, and the differences with the ERA5 reanalysis data are 4.80 mm in RMS and 4.07 mm in STD, and the differences with the sounding results are 4.80 mm and 4.07 mm in STD, respectively. The RMS and STD of the difference with the ERA5 reanalysis data are 4.80 mm and 4.07 mm, and the RMS and STD of the difference with the sounding results are 3.75 mm and 7.16 mm, respectively, which verifies that the PWV inversion results using the PPP-B2b service have a good accuracy. Finally, by analysing the correlation between the actual precipitation and the PWV inversion results of the rainstorm process in Hong Kong, the feasibility of BDS PPP-B2b service for the short-term early warning of rainstorm disasters is preliminarily verified.

Key words: precipitable water vapor inversion, precise point positioning, BeiDou Satellite Navigation System, real-time satellite orbit and clock correction, short-term early warning of torrential rainfall