Galleani Lorenzo, Tavella Patrizia
IEEE Trans Ultrason Ferroelectr Freq Control. 2015 May;62(5):791-801. doi: 10.1109/TUFFC.2014.006733.
The number of applications where precise clocks play a key role is steadily increasing, satellite navigation being the main example. Precise clock anomalies are hence critical events, and their characterization is a fundamental problem. When an anomaly occurs, the clock stability changes with time, and this variation can be characterized with the dynamic Allan variance (DAVAR). We obtain the DAVAR for a series of common clock anomalies, namely, a sinusoidal term, a phase jump, a frequency jump, and a sudden change in the clock noise variance. These anomalies are particularly common in space clocks. Our analytic results clarify how the clock stability changes during these anomalies.
精确时钟发挥关键作用的应用数量正在稳步增加，卫星导航是主要例子。因此，精确时钟异常是关键事件，其特征描述是一个基本问题。当异常发生时，时钟稳定性随时间变化，这种变化可用动态阿仑方差（DAVAR）来表征。我们针对一系列常见的时钟异常，即正弦项、相位跳变、频率跳变和时钟噪声方差的突然变化，获得了DAVAR。这些异常在空间时钟中尤为常见。我们的分析结果阐明了在这些异常期间时钟稳定性是如何变化的。
