基于高精度晶振的GPS秒时钟误差在线修正方法

Method for Correcting Errors of the GPS-clock Based on the High Precision Crystal Oscillator

当前电力系统已提出了不少基于全球定位系统(GPS)的高精度时钟的测量与控制技术,但是由于时钟信号的误差过大或稳定性差,这些时钟技术很难满足高可靠性同步控制领域的要求。在分析GPS秒时钟误差的基础上,结合高精度晶振无随机误差和GPS秒时钟无累计误差的特点, 通过对秒脉冲间的计数值进行动态平均和秒脉冲的误差估计,提出了利用高精度晶振在线修正 GPS秒时钟误差产生高精度时钟的方法。根据此方法研制了具有较高性价比的高精度时钟发生装置,并成功地应用于行波定位系统中。

Numerous measuring and controlling techniques based on the high precision GPS-clock available in power systems nowadays have a common problem, viz. the stability of the clock signal is very poor, thus these techniques can hardly meet the requirements of power systems, e.g. synchronous control with high reliability, phase difference measurement, and so on. By analyzing the GPS-clock error and combining the characteristics of the GPS-clock with the high precision oscillator, methods for correcting the GPS-clock on-line by comparing with the oscillator are proposed. As the GPS-clock is free from cumulative error and the high precision crystal oscillator is free from random error, the two clocks can be effectively combined. Through dynamically averaging the counting values between the second pulses and estimating the error of the second pulse, methods for correcting the GPS-clock on-line have been developed. The device for the high precision clock with high performance price ratio is designed, which has been successfully applied in traveling wave location. This work is supported by National Natural Science Foundation of China （No. 50577001） and Program for New Century Excellent Talents in Universities （No. NCET-04-0781）.