Research on frequency steering algorithm in satellite-based time reference establishment

Time reference established by navigation system needs to synchronize with ground time, which requires the use of frequency steering algorithm．Several frequency steering algorithms are examined in this paper, advantages and disadvantages of damping coefficient method, feedback clock difference measurement or frequency adjustment information method, and model predictive control (MPC) method are analyzed．The damping coefficient method has a low frequency of adjustment and is suitable for ground injection operation．Adjustment frequency of feedback clock difference or frequency adjustment information method is high, which is suitable for autonomous adjustment of space-borne equipment．The model predictive control algorithm has many adjustable parameters and can obtain higher frequency stability, but operation method is complicated．These algorithms can meet the requirement of frequency control accuracy of low orbit satellites by proper adjustments．