Performance Analysis of Real-Time Galileo Precise Point Positioning Using Different Dual-Frequency Ionosphere-Free Combinations

Presently, Galileo satellites are transmitting multi-frequency signals which provides opportunity to enhance Galileo precise point positioning (PPP) accuracy. The objective of this research is to investigate the performance of real-time Galileo-only PPP solution using the Galileo open service (OS) E1, E5a, E5b and E5 signals. Different dual-frequency ionosphere-free Galileo-only PPP processing models are used including, the E1/E5a PPP, E1/E5b PPP and E1/E5 PPP. The real-time precise orbit and clock products available from the Centre National d'Etudes Spatiales (CNES) are used in order to simulate the real-time mode. GPS/Galileo observations, spanning three successive days, from a number of globally distributed reference stations are acquired. Then, the datasets are processed using real-time PPP solution in static and semi-kinematic modes. The traditional real-time GPS L1/L2 PPP solution is used as a reference. The estimated convergence time and positioning accuracy is assessed and then compared with the GPS L1/L2 PPP solution counterparts. It is found that the overall 3D positioning accuracy is enhanced by about 11%, 6% and 8% for the Galileo E1/E5a PPP, E1/E5b PPP and E1/E5 PPP solutions, respectively, with respect to the GPS PPP solution counterparts in static mode. Additionally, improvements in the 3D position by about 25%, 11% and 17% are acquired from the Galileo E1/E5a PPP, E1/E5b PPP and E1/E5 PPP solutions, respectively, compared with the GPS L1/L2 PPP solution in semi-kinematic mode.