摘要
GPS校准晶振型频率源系统接收不到GPS信号时,仅能依靠晶振自身保持较高频率标准输出。该文针对短期GPS信号丢失后晶振输出频率漂移问题,提出一种基于Wiener过程的频率漂移校正补偿方法。该方法通过建立晶振输出频率的老化特性退化模型,将温度作为加速应力引入模型参数。利用GPS信号丢失前的系统历史校准数据,采用极大似然估计法估计模型扩散参数,采用Kalman滤波方法估计模型漂移参数,进而预测晶振失锁后的频率漂移量,完成对系统输出频率的补偿校正。将该方法应用到某GPS校准晶振型频率源系统中,结果表明在GPS信号丢失后的短期内,系统的输出频率准确度能够保持在9.7×10^(-11),满足短期内的计量需求。
The GPS calibrating crystal oscillator frequency source system can only rely on the crystal oscillator to keep the output at a high standard after GPS signals are lost. In this paper,an algorithm of maintaining frequency source punctuality based on Wiener process is proposed to correct and compensate for the output frequency drift of the crystal oscillator. Through analysis of historical calibrating data, an output frequency drift model was established with temperature and aging characteristics. Maximum likelihood estimation was applied to estimate the diffusion parameters of the model and Kalman filtering method was used to estimate its drift parameters.Furthermore, the output frequency drift in real time was predicted and the frequency of the system was compensated. The proposed method was applied to a GPS calibrating crystal oscillator frequency source system, and the results show that it can maintain the output precision of frequency at a degree as high as 9.7×10^（-11） after GPS signals are lost.
出处
《中国测试》
CAS
北大核心
2016年第6期14-18,共5页
China Measurement & Test
基金
国家杰出青年基金(61025014)
国家自然科学基金(61573365)
关键词
GPS校频
晶振
频率漂移
WIENER过程
GPS calibrating frequency
crystal oscillator
frequency drift
Wiener process
