Dependence of seasonal phenomena in coordinate time series on GNSS antenna mounting height

The purpose of this paper is analysing the correlation between the magnitude of the annual amplitude of seasonal changes in the coordinate components of GNSS reference stations and the height of the antenna mounting above the ground. For this purpose, the daily coordinate solutions of more than 500 GNSS reference stations that are part of the IGS (International GNSS Service) network were studied due to their distribution across the globe and long operating time, for some stations dating back to the 1990s. To minimize the impact of the tectonic plate movements authors adopted coordinates of reference stations inside each of the 21 tectonic plates. The coordinates in a topocentric reference frame were detrended in accordance with a linear model, with the objective of removing first-order trends. Subsequently, the seasonal yearly functions were calculated for each North, East and Up component. Finally, the amplitude of the seasonal factor for each station was determined. As a result of the analysis, the existence of annual amplitudes of coordinate changes was demonstrated for some of the stations, but no significant correlation between this phenomenon and the height of the GNSS antenna mounting was shown. In the case of the horizontal components, the majority of the station’s time series is characterized by the amplitude of seasonal function does not exceed 2.5–3 mm, and 5 mm for the vertical component.