Analysis and Discussion on the Optimal Noise Model of Global GNSS Long-Term Coordinate Series Considering Hydrological Loading

The displacement of Global Navigation Satellite System (GNSS) station contains the information surface elastic deformation caused by variation land water reserves. This paper selects long-term coordinate series data 671 International GNSS Service (IGS) reference stations distributed globally under framework World Geodetic 1984 (WGS84) from 2000 to 2021. Different noise model combinations are used for analysis, and optimal each before after hydrologic loading correction is calculated. results show that models global IGS diverse, component has different characteristics, mainly white + flicker (WN+FN), generalized Gauss–Markov (GGM) power law (WN+PL). Through specific analysis between time velocity station, it found maximum influence value vertical can reach 1.8 mm when hydrological considered. complex also have a certain on linear uncertainty station. Among them, random walking relatively obvious, its in elevation direction over 2 mm/year. When studying impact periodicity series, concluded whether calculated or not, obvious annual semi-annual amplitude changes, which most direction, up 16.48 mm.