Investigation and design of disciplined clock system based on BDS

This research focused on a design of disciplined clock based on BDS(BeiDou navigation satellite system). Measurement and analysis were performed for BDS timing signal based on the measurement of 1pps signal time offset between crystal oscillator and BDS timing receiver, using time interval counter with resolution as high as 250ps. According to the characteristics that the timing signal has a large jitter, but it has no bias over a long haul, a combination of least square fitting method and Kalman algorithm was applied to analyze time interval data, to depress the error of measurement noise, and estimate highly accurate time interval data. The results of the system´s measurement showed that frequency stability at 1000s was reduced to 1×10–13 from 1×10–11 after disciplining the crystal oscillator.