Study on the frequency forecast method of hydrogen maser based on EMD

The standard time/frequency signal from the time keeping laboratories is produced and maintained mainly by commercial hydrogen masers and cesium clocks. The former has excellent short-term stability and good low noise characteristics, but with frequency drift significantly, their long-term stability will be decreased with time gradually. So using a hydrogen maser as the UTC (k) frequency source, it is essential to predict the frequency and its drift of the hydrogen maser accurately. In this paper, a method, which forecasts frequency with empirical mode decomposition extracting frequency change trend of the hydrogen maser, is presented. And the forecasting frequency, as an amount of adjustment, is used to steer the signal from the master clock frequency source. The result shows that the frequency predicting method is simple and effective, to not only improves the frequency accuracy of UTC(k), but also retains good short-term stability properties of signals.