Detection and identification of atomic clock anomalies

Galleani, Lorenzo; Tavella, P.

doi:10.1088/0026-1394/45/6/s18

Cited by 39 publications

(16 citation statements)

References 9 publications

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“…The Time Integrity Service aims to test the capability to deliver a time integrity service to the GNSS users providing integrity information to improve user timing accuracy as well as positioning [11] , [12] , [13] .…”

Section: Service#8: Time Integritymentioning

confidence: 99%

Experimental time dissemination services based on European GNSS signals: The H2020 DEMETRA project

Tavella

Sesia

Cerretto

et al. 2016

2016 European Frequency and Time Forum (EFTF)

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DEMETRA aims to be a prototype of an European time dissemination service, based on the timing signal of the European Galileo system, adding particular features likeamong the others -certification, calibration, or integrity, that could be of interest to a wide range of users belonging to different sectors as traffic control, energy distribution, finance, telecommunication, and scientific institutions. Nine time dissemination services are proposed. The paper will report about the development status and the first experimentation results of the system, showing potentialities and limits of the proposed time dissemination services, aiming to foster the exploitation of the European GNSS for timing applications.

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Section: Service#8: Time Integritymentioning

confidence: 99%

Experimental time dissemination services based on European GNSS signals: The H2020 DEMETRA project

Tavella

Sesia

Cerretto

et al. 2016

2016 European Frequency and Time Forum (EFTF)

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“…이런 원자시계의 주파수 도약 현상을 검출하기 위한 다양한 기법들이 연구되고 있으나, 대부분 의 기법들은 평균값을 이용하여 도약 유무를 판 단하기 때문에 검출이 느리고 도약 유무는 알 수 있으나 도약 위치를 찾지 못하는 방법도 있다 [6][7][8] 2 II-R RB 18 II-R RB 3 II-A CS 19 II-R RB 4 II-A RB 20 II-R RB 5 II-A RB 21 II-R RB 6 II-A RB 22 II-R RB 7 IIR …”

Section: 그림 1 Tks Block Diagramunclassified

Detection of GPS Clock Jump using Teager Energy

Heo

Cho²,

Heo³

2010

Journal of the Korean Society for Aeronautical & Space Scie

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In this paper, we propose a simple technique for the detection of a frequency jump in the GPS clock behavior. GPS satellite atomic clocks have characteristics of a second order polynomial in the long term and a non-periodic frequency drift in the short term, showing a sudden frequency jump occasionally. As satellite clock anomalies influence on GPS measurements, it requires to develop a real time technique for the detection of the clock anomaly on the real-time GPS precise point positioning. The proposed technique is based on Teager energy which is mainly used in the field of various signal processing for the detection of a specific signal or symptom. Therefore, we employed the Teager energy for the detection of the jump phenomenon of GPS satellite atomic clocks, and it showed that the proposed clock anomaly detection strategy outperforms a conventional detection methodology.

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“…We see that the DADEV is an increasing surface which reveals the increase in the variance of the frequency deviation. The shape of the DAVAR changes with respect to the clock anomaly, and it can hence be used as a diagnostic tool [4].…”

Section: The Dynamic Allan Variancementioning

confidence: 99%

“…The dynamic Allan variance (DAVAR) [1], [2], [3] can be used to represent the change in stability of an atomic clock, and, in general, of any precise oscillator. Consequently, the DAVAR can be used to detect and identify clock anomalies [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Fast computation of the dynamic Allan variance

Galleani

Tavella

2009

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

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The dynamic Allan variance (DAVAR) is a tool that allows to understand if the stability of an atomic clock is changing with time. Since an anomaly in the clock behavior generates a change in its stability, the DAVAR can be used to monitor the performances of a clock. In this paper we present a fast algorithm for the computation of the DAVAR, which outperforms the classical computational method. I. INTRODUCTIONThe performances of an atomic clock change throughout its life, due to aging, cyclostationary effects such as temperature and humidity, as well as sudden breakdowns. Therefore, also its stability changes with time. The dynamic Allan variance (DAVAR) [1], [2], [3] can be used to represent the change in stability of an atomic clock, and, in general, of any precise oscillator. Consequently, the DAVAR can be used to detect and identify clock anomalies [4], [5].A critical point of the DAVAR is its computational cost. The DAVAR is, in fact, a sliding version of the Allan variance [6]. To compute the DAVAR, at every time instant, the signal representing the clock phase deviation is truncated, and its Allan variance represents the clock stability at the given time instant. Therefore, if a signal has N samples, the computation of the DAVAR requires, in general, the evaluation of N Allan variances, which can turn in a computational burden if N is large.By using a recursive formulation of the Allan variance it is possible to formulate the DAVAR in a recursive way [7], [8]. Such formulation can be used to develop a fast computational algorithm, whose performances are far superior to those of the classical DAVAR algorithm. In this paper we give the recursive formulation of the DAVAR, and we show the performances of the fast algorithm.

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Detection and identification of atomic clock anomalies

Cited by 39 publications

References 9 publications

Experimental time dissemination services based on European GNSS signals: The H2020 DEMETRA project

Experimental time dissemination services based on European GNSS signals: The H2020 DEMETRA project

Detection of GPS Clock Jump using Teager Energy

Fast computation of the dynamic Allan variance

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