基于GPS校准的数字式守时钟守时算法研究

通常守时系统都采用高稳晶体振荡器作为频率标准,但由于温度和老化等原因导致其长期稳定度不尽如人意,严重影响时钟的守时精度,改变电路的分频比可以对其进行补偿。数字式守时钟采用了固定频率晶振驱动的分频比可精细微调的基于加法器的时钟电路。首先介绍了一种GPS校准的数字式高精度守时钟并讲述了其工作原理,然后对如何快速、准确的在数字式守时钟中得到晶振的分频比补偿值进行了研究,提出了算术平均值滤波算法和卡尔曼滤波算法这两种算法,并搭建了实验平台。经验证,卡尔曼滤波算法在快速性和准确性上要优于算术平均值算法。

Research on Time Keeping Algorithm in GPS Disciplined Digital Timekeeping Clock

Usually,a high stability crystal oscillator is used in the timekeeping system as a clock frequency standard,but its drawbacks of long-term stability do not satisfy applications because of its aging or some other reasons.Compensation can be achieved by varying the frequency dividing radio for the long-term stability of crystal oscillator.Digital timekeeping clock adopt an adder-based clock circuit,with its frequency dividing radio being able to be adjusted fine and smoothly.First a precise GPS disciplined digital timekeeping clock and its operating principle are introduced in this paper,then on how to achieve the compensation of the frequency dividing radio in the digital timekeeping clock quickly and accurately is studied.The arithmetic mean filter algorithm and Kalman filter algorithm are proposed,and experimental platform is built.It is proved that Kalman filter algorithm is superior to the arithmetic mean algorithm in speed and accuracy.