Atomic clock frequency steering method based on optimal control theory

An improved frequency steering method for hydrogen maser clocks is proposed, which uses the linear quadratic Gaussian (LGQ) optimal control algorithm to calculate the frequency of hydrogen maser clock and to achieve frequency steering of the hydrogen maser. Firstly, it introduces the design of the Kalman filter and the LQG algorithm that incorporates the Kalman filter. Secondly, the performance of the LQG algorithm is confirmed. Based on the simulation data of abnormal signals, the processing effectiveness of the LQG algorithm on abnormal signals is demonstrated. Finally, the implementation of the LQG algorithm is predicated on the measured data. A paper time scale is generated based on clock comparison data of the time-keeping system. Utilizing the paper time scale as a reference, the LQG algorithm is employed to steer the frequency of the hydrogen maser clock, and then the signal after frequency steering is obtained. The short-term stability (⩽ 115200s) of the signal after frequency steering exhibits a higher level of precision compared to that of reference paper time scale. The hourly stability of the signal after frequency steering is 2.96E-15, which is 19.89% higher than that of the reference paper time scale; the one-day stability of the signal after frequency steering is 3.49E-16, which is 18.36% higher than that of the reference paper time scale. It can be discerned from the results that this method not only improves the short-term stability of the signal after frequency steering, but also improves the accuracy of the signal after frequency steering.