Abstract: Compared with PPP timing, real-time kinematic timing based on GNSS carrier phase observations can effectively avoid dependence on real-time precise orbit and clock products, and is of great significance to short-distance kinematic and static high-precision time users. In order to verify the performance of GNSS realtime kinematic timing, a timing experiment was carried out with the GPS system as an example based on the time and frequency resources as well as the observation data of three GNSS tracking stations for up to 2 months of the National Time Service Center of the Chinese Academy of Sciences. Compared with the PPP time transfer, the standard deviation of differences from realtime kinematic timing result is better than 0.15ns; compared with the result of optical fiber two-way time transfer, the standard deviation of differences from real-time kinematic timing result is better than 0.5ns. The experiments show that GNSS realtime kinematic timing accuracy can reach the sub-nanosecond level, which can provide an important reference for the future application of this timing technique.

Key words: real-time kinematic, precise timing, GNSS carrier phase, single difference between stations, sub-nanosecond