Robust Detection of Fast and Slow Frequency Jumps of Atomic Clocks

This paper presents a frequency jump detector for atomic clocks. The detector considers both fast frequency jumps, which are abrupt variations of the clock frequency trend, and slow frequency jumps, which correspond to variations of the frequency trend over a finite time interval. These anomalies are particularly critical to space clocks in global navigation satellite systems (GNSSs). The developed detector is robust in the sense that it can deal with time-varying frequency trends, sinusoidal terms, outliers, and missing data. The detection performances are analyzed both analytically and numerically, and the effectiveness of the detector is shown by applying it to GNSS experimental data, as well as to simulated clock data.