Modeling and assessment of Galileo PPP one-way timing with RT-product

Precise point positioning (PPP) technology is widely used in positioning, navigation, and timing. In order to meet the needs of users for real-time high-precision time information, a real-time Galileo PPP one-way timing model based on existing real-time (RT) products (CAS, CNES, GMV, and WHU) was established and applied for the timing field. Experiments were designed with 8 GNSS stations with an external H-MASER clock to research Galileo PPP timing with 25 day observations. For the modified Allan deviation (MDEV) of Galileo PPP timing solutions, similar to the timing solutions of GPS, the MDEV of Galileo PPP with CAS and CNES shows worse short-term frequency stability, with 1 to 2 x 10-13 at 960 s stability, and indicates similar long-term frequency stability, with about 5-6 x 10-15 at 61 440 s stability. For Galileo PPP time transfer, the standard deviation values are about 0.01-0.49 ns for all time-links with different products. For the stability of Galileo time transfer, the similar characteristic of Galileo time transfer is comparable to that of GPS. For short-term stability, the MDEV of all time-links from Galileo PPP ranges from 2 x 10-14 to 3 x 10-14 at 960 s. For long-term stability, 1 to 2 x 10-15 levels can be reached at 61 440 s for all time-links, except for that of CNES.