The New PWV Conversion Models Based on GNSS and Meteorological Elements in the China Region

Abstract

To address the problems of cumbersome processes, large data, and error accumulation in the calculation of conventional GNSS precipitable water volume (PWV), the multi-factor PWV conversion models were established using the multiple linear regression fitting method. This paper analyzed the correlation between PWV and zenith tropospheric delay (ZTD), surface temperature (T), and atmospheric pressure (P) based on the data from 38 GNSS stations in the China region from 2017 to 2018. The research results showed that the mean deviation of the one-factor PWV conversion model based on the GNSS-ZTD was 12.16 mm, and its RMS was 14.30 mm. After adding surface temperature as an independent variable to form the two-factor PWV conversion model, the mean deviation and RMS decreased to 9.07 mm and 11.15 mm. The mean deviation of the two-factor PWV conversion model based on atmospheric pressure and GNSS-ZTD was 0.31 mm, and its RMS was 0.39 mm. The mean deviation of the three-factor PWV conversion model based on surface temperature, atmospheric pressure, and GNSS-ZTD was 0.33 mm, and its RMS was 0.38 mm. The accuracies of the two-factor and three-factor PWV conversion models were similar. The external precision assessment of PWV conversion models was verified by 12 GNSS stations unused for the modelling establishment. The mean deviation and RMS of the two multi-factor PWV conversion models were both less than 0.16 mm and 0.33 mm, which proves their widespread applicability in the China region.