In many geodetic analyses, it is important to consider the effect of earth tide on the instantaneous position of a station and its subsequent influence on the computation and interpretation of time series of coordinates as well as related data products. The tidal effect and temporal variations in the position of the IGS (International Global Navigational Satellite Systems [GNSS] Service) stations at Hyderabad (India), Ankara (Turkey) and Beijing Fangshan (China), due to solid earth tides has been studied. Surface tidal displacement of the station has been computed on daily basis for a month, based on the concept of gravity. Further, mean daily coordinates of the station been computed using static precise point positioning (PPP) method for a month. Results show that the station undergoes temporal displacements and its coordinates vary continuously within a day and all the days in the month. The maximum range in vertical displacement of the station has been found to be about 48 cm in a day over a period of a month and that along the north and east directions is respectively 8 cm and 14 cm. This is the maximum range but the mean value in the vertical displacement is 6 cm and along north and east is 1.7 cm and 0.09 cm, respectively. The ranges in variation in the mean value of geodetic latitude, longitude, and height of the station have been found to be 1.23, 2.73, and 3.52 cm, respectively. Further, it has been found that the tidal oscillations follow some periodicity, and thus need to be studied independently for all stations.
Volume 132, 2023
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