Satellite Selection Method According to Signal Levels of Multi-Constellation GNSS

YDilution of Precision (DOP) is used as a parameter representing the geometrical position of visible satellites, and as a measure of position error of Global Navigation Satellite Systems (GNSSs). In previous studies, the Weight DOP (WDOP) was proposed by setting different weights based on the signal quality of the GPS satellite, and the signal quality of satellites was evaluated based on the elevation angle. In this study, Multi-ConstellationWeighted DOP (MWDOP) is defined by expanding the weight matrix of GPS to the global navigation satellite systems (GPS, GLONASS, Galileo, and Beidou). The weight matrix is defined through actual data considering the elevation angle and pseudorange for each satellite system. Furthermore, the satellite selection algorithm is set up through sensitivity, which is calculated by dividing the difference between the DOP calculated for the entire set of satellites and the DOP calculated for a set excluding specific satellites divided by the DOP calculated for the entire set of satellites. If the calculated sensitivity is large, the excluded satellites are considered to have a large effect on the satellite positioning. This study provides more reliable criteria for selecting satellites by comparing DOP sensitivity and MWDOP sensitivity.