原子钟两级驾驭算法及在建立GNSS时间基准中的应用

摘要

本文提出了一种原子钟驾驭算法，方法是使用等价于Kalman滤波器加延迟器的数字锁相环（DPLL）。本文完整地推导了DPLL的闭环系统传递函数和闭环误差传递函数，给出了其实现结构，和每次的对于被驾驭原子钟的调整量，并给出了使DPLL输出信号的频率稳定度最优的参数选取方法。在此基础上，提出了使用两个这样的DPLL级联起来的二级驾驭算法。理论分析和仿真实验都表明：该算法相比传统原子钟驾驭算法，参数选取更容易，可以保证输出信号的频率稳定度最优；并保证输出信号与第一级的参考输入保持时间同步。该两级驾驭算法可以应用于设计锁相振荡器，即先用铯钟驾驭氢钟，然后再驾驭数控振荡器（NCO）；也可以应用于建立 GNSS 时间基准，即先用 UTC （BSNC）驾驭产生BDT，然后再用BDT驾驭主控站主钟来产生BDT（MC）。%An atomic clock steering algorithm is proposed by utilizing a DPLL equivalent to a Kalman filter with a delay.The close-loop system transfer function and the close-loop error transfer function are derived.The implement structure of the DPLL,and the adjustment to the atomic clock to be steered in each time are shown.A method for choosing the param-eter such that the output frequency stability is optimal is also carried out.Then,a twice steering algorithm by means of two same DPLLs in the cascade form is proposed.The theoretical analyses and simulations all indicate that it is easier to choose parameters in the algorithm than the traditional algorithms,the output synchronizes to the first input and its frequency stabili-ty is optimal.The twice steering algorithm is useful for designing the phase-locked oscillator,where the number-controlled oscillator is first steered to a hydrogen maser and then steered to a cesium clock.The algorithm is also useful for forming a GNSS time.The method first steers BDT to UTC(BSNC),and then steers BDT(MC)to the steered BDT.