Galileo satellite data contribution to GNSS solutions for short and long baselines

Abstract

GALILEO (Europe's Global Navigation Satellite System) is going full speed ahead to achieve full constellation by 2020. Since GALILEO is currently an emerging system, the contribution of these satellites to GNSS (Global Navigation Satellite System) solutions needs to be investigated. For this purpose, GNSS data collected at three IGS (International GNSS Service) MGEX (Multi GNSS Experiment) stations are analyzed. For the analyses, GPS (Global Positioning System) only, GLONASS (Russia's Global Navigation Satellite System) only, GALILEO-only and combined solutions are tested and also effect of baseline length is examined. The results indicate that compared to GPS, GLONASS and ALL (GPS+GLONASS+GALILEO) solutions, GALILEO results vary greatly. When GALILEO observations are combined with other observations, the precision goes down. That is to say, for short baseline solution, GALILEO results fluctuate around 1 cm in the horizontal plane and in the vertical plane variations are mostly within 3-5 cm. For long baseline solution, GALILEO results are going up and down in the horizontal between 2 and 3 cm and in the vertical roughly 10 cm. In terms of accuracy, for short baseline solution, GALILEO-only solution is close to GPS-only solution; yet, we cannot say the same thing for long baseline solution.