An analysis of multisource tropospheric hydrostatic delays and their implications for GPS/GLONASS PPP-based zenith tropospheric delay and height estimations

• Published in: Journal of geodesy 2021-07, Vol.95 (7), Article 83
• Main Authors: Zhang, Hongxing, Yuan, Yunbin, Li, Wei
• Format: Article
• Language: English
• Subjects: Corrections; Earth and Environmental Science; Earth Sciences; Empirical models; Errors; Geodetics; Geophysics/Geodesy; Global positioning systems; GPS; Height; Latitude; Navigation; Navigation satellites; Navigation systems; Navigational satellites; Original Article; Regions; Troposphere; Weather conditions
• ISSN: 0949-7714; 1432-1394
• DOI: 10.1007/s00190-021-01535-3

To obtain better zenith hydrostatic delay (ZHD) corrections for global navigation satellite system (GNSS) applications, seven types of Vienna mapping function 1 (VMF1) and VMF3-like ZHD models provided by the Vienna University of Technology (TU Wien, TUW), University of New Brunswick (UNB) and GeoForschungsZentrum Potsdam (GFZ) are evaluated. Firstly, we find that the conventional method for implementing VMF1/VMF3-like ZHD models has issues when applied over regions with highly variable topography. Therefore, we propose an improved implementation method (called Trop_vertical) based on an empirical model as well as a second version, called Trop_vertical-II, which further corrects for small residual biases. The results show that the Trop_vertical-II can effectively reduce the large errors reported in previous studies for complex terrains and yields an improvement in global accuracy of up to 50% over the conventional method. Then, the multisource ZHD models are evaluated and intercompared globally. The results reveal some deficiencies with the TUW-VMF1 over certain regions. The newly developed ZHD models from the TUW (TUW-VMF3) and GFZ (GFZ-VMF3) both achieve reliable performances globally, but there is a systematic difference (~ 2.9 mm) between them. The forecast VMF1/VMF3-like models can well capture the rapid ZHD variation in challenging weather conditions. Finally, the impacts of a priori ZHD errors on both GPS-only and GPS/GLONASS precise point positioning (PPP)-based zenith total delay (ZTD) and height solutions are examined globally. The results suggest that the sensitivities of PPP-ZTD/height solutions to a priori ZHD errors decrease by adding GLONASS data at high latitudes but increase at low latitudes.