Research on time scale algorithm based on hydrogen masers

Abstract

In order to ensure the long-term stability of the time scale, the traditional timekeeping clock ensemble is mainly composed of a cesium clock and a few hydrogen masers. Since 2014, the Bureau International des Poids et Mesures (BIPM) has changed the weighting method of atomic clocks, using the predictability of atomic clocks to weight the global atomic clocks to obtain the International Atomic Time (TAI) and Coordinated Universal Time (UTC). Because of the good predictability of hydrogen masers, less than one third of the number of atomic clocks in TAI/UTC calculation is hydrogen masers which has gained 75% weight. Effective utilization of hydrogen masers has become a research hotspot in timekeeping laboratories. In order to give full play to the advantages of hydrogen masers in timekeeping, the time scale of hydrogen masers is tested in this paper. Firstly, the frequency drift parameters of hydrogen masers are dynamically estimated by using the minimum error theory. Then the estimated parameters are applied to a real-time exponential filtering time scale algorithm. The results show that the stability of the time scale produced by this method can reach 6e-15/day, and the absolute maximum deviation from TA(NTSC) within a month can be kept within 5 ns, which is better than the time scales produced by a traditional fixed frequency drift parameters method and the classical weighted averaging algorithm ALGOS.