Study on the method of measuring and estimating the time synchronization accuracy under constellations autonomous operation based on the ground testing system

Constellations autonomous operation capability of the satellite navigation system is one of the primary ways for improving system´s survivability. It is unrealistic obviously that the satellites do not update the data to test and verify the constellations autonomous operation capability under the condition of satellite navigation system can support by the ground-monitoring system. The study of measuring and estimating constellations autonomous operation time synchronization´s accuracy in condition of the satellite navigation system operate normally is so little. This paper discusses the importance of testing and verification for diffident working mode, it provides one kinds of method of measuring and estimating the time synchronization accuracy under constellations autonomous operation based on the ground testing system. In the paper, it gives the basic principle and the computational model, verifying and analysing the method by simulation data. This method provides technical support for building global satellite navigation system´s inter-satellite link.