The present invention provides a high-reliability
clock synchronization method for a micro PNT
system based on CSAC. First, the 1pps
signal of the CSAC and the 1pps
signal of the GNSS are acquired in real time to calculate the
clock difference
signal. When the GNSS signal is valid, it is determined whether the
clock difference signal is greater than a preset threshold. If it is greater than the threshold, the coarse adjustment function of the
chip-level
atomic clock is enabled. Otherwise, the following fine adjustment operation is performed. If the 1pps signal of the GNSS fails, the
system will automatically enable the clock hold function, and predict and maintain the time accuracy of the CSAC through the
extended Kalman filter method, ensuring that a high
time synchronization accuracy can be maintained during the period when the GNSS signal is lost. Once the GNSS signal is restored, the
system will exit the clock hold mode and re-synchronize with the GNSS. The present invention solves the
clock synchronization problem between CSAC and GNSS, thereby ensuring high-precision
time synchronization of the system and significantly enhancing the reliability of the system.