Time difference monitoring is necessary for GNSS compatibility and interoperability. It will improve the consistency and the responsibility of time service by GNSS. “Time Difference Monitoring Between BDT and the Other GNSS Time” given by Prof. Haibo Yuan in the Munich Satellite Navigation Summit 2017 demonstrated the research process and achievement of NTSC in this field.

There are three methods for GNSS time difference monitoring: time links method, single station method and multi stations method. The research and experiments are carried out based on these methods in NTSC and the monitoring results are presented in summit this time. Researches on the GNSS time difference prediction model and the time link calibration will be conducted in the near future for a more accurate monitoring result between BDT and the other GNSS time. After this report，Many other possible methods and new techniques are lively discussed by researchers.

Time difference monitoring of GNSS has attracted a lot of attention in recent years. If users get the time difference of GNSS, they can use the different GNSS at the same time. In that case, users will get more accurate time and position easily . So time difference monitoring of GNSS is becoming the research focus and the construction emphasis of GNSS. In order to promote the compatibility and interoperability of the GNSS, BDS has paid much attention on it and its related research and has also provided the time difference of BDT and GPST, BDT and GLNT in the test satellite. And BDS will provide the formal time difference parameters in the BDS global navigation satellite system in the future. 

(Haibo Yuan and Wei Li contributed to this report)