Self-Monitoring and Self-Assessing Atomic Clocks

Chan, Y.C.; Johnson, W.; Karuza, Sarunas K.; Young, A.M.; Camparo, J. C.

doi:10.1109/tim.2009.2023817

Cited by 11 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generally speaking, there are two methods to evaluate atomic clocks: (1) comparing the clock signal with standard reference whose stability is much better than the evaluated clock and (2) making intercomparison among three or more clocks whose stability is almost the same. Because there is no standard reference in the satellite and the performance of satellite clocks is similar, we make use of the second method to realize Self-Monitoring for anomalies.…”

Section: Self-monitoring Methods For Anomaly Of Satellitementioning

confidence: 99%

“…So far, researchers have proposed schemes to monitor anomalies of clock, such as Interferometric Detection Method [1], Least Square (LS) Detection Method [2,3], Generalized Likelihood Ratio Test (GLRT) [4][5][6], Kalman Filtering Method [7][8][9][10], and Dynamic Allan Variance (DAVAR) Method [5,[11][12][13]. Though their schemes have been proved to be effective for some (not all) anomalies, some extra work is still needed to realize Self-Monitoring.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Research on Self-Monitoring Method for Anomalies of Satellite Atomic Clock

2016

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

Atomic clock is the core component of navigation satellite payload, playing a decisive role in the realization of positioning function. So the monitoring for anomalies of the satellite atomic clock is very important. In this paper, a complete autonomous monitoring method for the satellite clock is put forward, which is, respectively, based on Phase-Locked Loop (PLL) and statistical principle. Our methods focus on anomalies in satellite clock such as phase and frequency jumping, instantaneous deterioration, stability deterioration, and frequency drift-rate anomaly. Now, method based on PLL has been used successfully in China’s newest BeiDou navigation satellite.

show abstract

Section: Self-monitoring Methods For Anomaly Of Satellitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Research on Self-Monitoring Method for Anomalies of Satellite Atomic Clock

2016

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

show abstract

“…The slope of the cumulative sum reflects the average behavior of the measurement and can be used to detect frequency jumps. Other techniques for fault detection in clock signals include trend analysis and filtering of the frequency signal [18][19][20], the optimal stopping method [21], and interferometric analysis [22]. Fault detection in clock ensembles is further discussed in [23][24][25] using Kalman filters.…”

Section: State Of the Artmentioning

confidence: 99%

“…For each of these we devise a dedicated detector based on the generalized likelihood ratio test (GLRT), which accounts for the statistical distribution of the observable in both nominal and faulty conditions. We derive a model-based test and a [7][8][9][10][11] This work Dynamic Allan variance [12][13][14][15][16] This work Trend analysis-smoothing-recursive filters [18][19][20] [ 27, 28] Optimal stopping method [21] -Average, least-squares, standard deviation on sliding windows [17] [ 26] Interferometry [22] self-consistency test. In the model-based test the detector compares the current observation to the value predicted by a clock model: any deviation between the two can originate from a fault, but also from a mismodelling of the expected behavior.…”

Section: Introductionmentioning

confidence: 99%

Detection and identification of faults in clock ensembles with the generalized likelihood ratio test

2022

View full text Add to dashboard Cite

In this paper we propose an approach for performing fault detection and identification in clock ensembles based on the generalized likelihood ratio test. We show that by applying a set of purposefully-designed statistical tests, one can successfully detect faults occurring in a clock of the ensemble, and identify which measurement in the ensemble is most likely to have triggered the detection. We first develop the theoretical framework for the characterization of the detectors and their performance, and validate the derivations via Monte Carlo simulations. Then, we apply the statistical tests to an ensemble of cesium clocks, aiming at detecting and identifying three types of non-nominal behaviors. The faulty conditions are obtained by injecting a pattern of phase steps, a phase and frequency drift, and an oscillatory phase component.

show abstract

“…In our "interferometric method," we compare a clock's signal with a delayed version of itself [2]. Specifically, the output signal of our interferometric system is proportional to the clock's fractional frequency deviation, Δy, averaged over the delay, Δt.…”

Section: Introductionmentioning

confidence: 99%

Autonomously measuring an atomic clock's allan variance

Camparo

Chan

Johnson

et al. 2009

2009 IEEE International Frequency Control Symposium Joint With the 22nd European Frequency and Time Forum

View full text Add to dashboard Cite

In this work, we demonstrate that an atomic clock can autonomously assess its own frequency stability and integrity by comparing the phase of its output signal to a delayed version of itself in what is essentially an interferometric technique. Using a high-quality crystal oscillator as a surrogate delay line, we demonstrate that fractional frequency variations at the level of 10 -12 are detectable, and that a Cs clock's short-term Allan deviation can be measured without reference to another standard. The paper concludes with a discussion of how an ambiguity in the method might be resolved, and how the method might be employed in the optical domain.

show abstract

Self-Monitoring and Self-Assessing Atomic Clocks

Cited by 11 publications

References 17 publications

Research on Self-Monitoring Method for Anomalies of Satellite Atomic Clock

Research on Self-Monitoring Method for Anomalies of Satellite Atomic Clock

Detection and identification of faults in clock ensembles with the generalized likelihood ratio test

Autonomously measuring an atomic clock's allan variance

Contact Info

Product

Resources

About