Study of GNSS Multi-Constellation Performance in Single Point Positioning and Differential Positioning in Indonesia

The Global Navigation Satellite System (GNSS) is a satellite-based positioning system used for various high-accuracy applications. In Indonesia, GNSS is used to provide national horizontal geodetic control networks and in mapping activities. Utilization of the multi GNSS constellations is expected to improve GNSS-based positioning both in absolute and differential terms in Indonesia. This study aims to determine multi GNSS constellations' data quality and performance in Single Point Positioning (SPP) and differential positioning. This study was conducted using GNSS observation data with varying baseline lengths in an ideal condition for measurement. The satellite visibilities, Dilution of Precision (DOP), and pseudorange multipath of each constellation were then analyzed to determine the measurement data quality. In addition, the data was used to obtain the coordinates and their accuracy from each observation point using six different combinations of satellites. The use of GPS, GLONASS, Galileo, and Beidou satellites simultaneously increases the visibility and strength of satellite geometry (with a lower DOP magnitude). Beidou was the largest contributor, with 11 satellites observed for each observation epoch. The SNR value of each satellite constellation tends to be the same for all satellites. The SNR value for each satellite is in the range of 30-60 dBHz for L1 and 20-40 dBHz for L2. GPS satellites have the lowest multipath value. The pseudorange multipath value for GLONASS satellites is constant with a value of-2 to 2 m from low to high elevation, while on other satellites, the multipath value tends to decrease as the satellite elevation angle increases. The combination of GPS and Beidou is better than using all GNSS satellites for positioning applications in Indonesia.