Kalman filter analysis of precision clocks with real-time parameter estimation

An optimum algorithm has been developed for estimating the time, frequency, and frequency aging of clocks and oscillators while simultaneously estimating the noise spectrum. The algorithm is sufficiently general to be used with all types of quartz oscillators and atomic clocks yet the approach is appropriate for use with an embedded controller in automated systems intended for field applications. The technique is adaptive-it calculates and updates estimates for all required clock parameters as observations occur. Data are accepted whenever available and are not required to be at fixed multiples of a fixed sampling time. Only coarse estimates of the parameters are required to initialize the computation