Abstract: As to the autonomous navigation requirements, the paper analyzes the availability of the autonomous time synchronization with relative clock error and on-board atomic clock, verified the coherence between the on-board atomic clock characteristic and autonomous filtering clock result, and estimated the clock prediction peculiarity within/without time reference and inter-satellite message. The results demonstrate that the clock error prediction result will be not available and increase with onboard clock characteristic and filtering parameters when the reference time of ground or other satellite and inter-satellite message are missed, and has fast convergence ability as the satellite receives the time reference information; other satellites can autonomously adjust with some satellite or anchor station as clock reference; when inter-satellite message can be satisfied, the constellation clock error has integrate draft; as to the designed algorithm, the integrate draft can reach 60 m; autonomous time synchronization error based on the onboard absolute clock error is rather stable which does not increase with time, and the relative clock error RMS is 0.6 m.

Key words: autonomous time synchronization, inter-satellite message, on-board atomic clock, filtering parameters, time reference