Özet:

GPS, GLONASS, Galileo, BeiDou are used in global positioning studies, while IRNSS and QZSS are used regionally. Until recently, point positions were determined using GPS, GLONASS, and BeiDou satellite systems. Since 2020, the Galileo satellite system has also been used. The accuracy of point positioning with GNSS depends on the satellite system used, processing software, data collection time/interval, etc. In this study, the effect of the Galileo satellite system on point positioning was investigated depending on the data logging time. For this purpose, daily RINEX data of 7 selected TUSAGA stations between October 15, 2020, and November 13, 2020, were analyzed in 2, 4, and 12-hour increments using 14 IGS station RINEX data, and the solutions were evaluated with GAMIT/GLOBK according to GPS (G), GLONASS (R), Galileo (E), and GPS+GLONASS+Galileo (GRE). As a result of the evaluations, the approaches of other satellite combinations to the daily coordinates obtained using only GPS were analyzed. In the analyses conducted, it was concluded that the accuracy increases as the measurement time increases and that GRE, Galileo, and GLONASS satellite combinations provide the best approximation to GPS coordinates, respectively.