Carrier phase time transfer with Galileo observations

Timing applications with GPS-only precise point positioning (PPP) have been extensively assessed and studied, while those with the other satellite systems (i.e., GLONASS, BDS, and Galileo) are gradually becoming the research focus. The contribution of this work is to comprehensively evaluate and investigate Galileo-only precise time transfer with the final products from five analysis centers (ACs) (COM, WUM, GRM, SHA and GBM) and one real-time products (i.e., CLK93), together with one-month period (April 2019) observations from 19 MGEX tracking stations. The experimental results showed that STD values of time difference calculated from Galileo-only PPP were all less than 0.2 ns with the above six type of precise products. Galileo-only time transfer with four AC final products (COM, GRM, GBM and WUM) agreed with each other very well, while that of SHA products showed worst performance, which may be attributed to its larger sampling interval of satellite clock products (i.e., 5 min). Meanwhile, the performance of Galileo-only PPP time transfer with CLK93 product presented slightly worse than that with the final products. Different from the performance with the final products, Galileo-only PPP time transfer with CLK93 products demonstrated worse performance than that of GPS-only PPP, which is primarily owing to the worse Galileo products in the current real-time products generation process. (C) 2020 Elsevier Ltd. All rights reserved.