Impact of tropospheric and atmospheric loading models on the repeatability of GNSS solutions

The tropospheric effect is considered as one of the most significant sources of error limiting GNSS positioning accuracy. In addition, atmospheric mass loading, which is seasonally variable, can also affect the repeatability of daily GNSS positions to a minor level. Therefore, the correct modelling of tropospheric and atmospheric loading effects is crucial to achieve the suitable accuracy, especially in high-accuracy GNSS applications. The aim of this work is to study the impact of tropospheric modelling and atmospheric mass loading on the repeatability of daily GNSS solutions. The research methodology is based on the analysis of GNSS data obtained from the IGS network, incorporating multiple processing scenarios including different mapping functions, elevation masks, and atmospheric mass loading. The analysis studies data from contrasting geographical locations (mid-latitude and polar regions), and accounts for seasonal variations by analysing measurements taken during both summer and winter periods, enabling a comprehensive assessment of how these various factors influence GNSS data processing outcomes, especially the daily position repeatabilities. The obtained results show that the efficiency of the mapping functions varies from one region to another. Furthermore, the consideration of atmospheric mass loading affects the performance of the mapping functions.