Abstract:We analyze the characteristics and changes of system time offset parameters of each GNSS, and compare and evaluate the broadcast system time offsets according to the data published by BIPM and the time and frequency bulletin, respectively. The results show that there is a bias of more than 10 ns in the system time offsets of GPS/GLONASS/Galileo broadcasted by BDS. The accuracy of system time offsets between GLONASS and GPS, as well as Galileo and GPS, obtained indirectly through BDS, are better than that of the same parameters broadcasted by GLONASS and Galileo.