The dynamic Allan Variance IV: characterization of atomic clock anomalies

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 62; no. 5; pp. 791 - 801
• Main Authors: Galleani, Lorenzo, Tavella, Patrizia
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-05-2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anomalies; Approximation methods; Clocks; Dynamics; Ferroelectric materials; Mathematical analysis; Navigation; Noise; Oscillators; Satellites; Stability; Stability analysis; Time-frequency analysis; Variance
• ISSN: 0885-3010; 1525-8955
• 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.