Impact of new frequency standards on the international time scales

AbstractThe reference time scales maintained at the International Bureau of Weights and Measures (BIPM) are constructed with data from industrial clocks and primary frequency standards operated in national metrology laboratories and observatories world-wide distributed. Clocks are compared making use of techniques of time transfer between remote sites. The algorithm of calculation relies on clock weighting and clock frequency prediction. We briefly present hereafter the influence of some clocks on the scales, as well as the possibilities for improvement.

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Pulsar Astrometry and Improved Terrestrial Clocks

International Astronomical Union Colloquium ◽

10.1017/s025292110004118x ◽

1996 ◽

Vol 160 ◽

pp. 113-114

Author(s):

Demetrios N. Matsakis ◽

Frederick J. Josties ◽

Roger S. Foster

Keyword(s):

Inverse Problem ◽

Time Scales ◽

Time Scale ◽

World Wide ◽

State Of The Art ◽

Frequency Standards ◽

A Value ◽

The World ◽

Averaging Time ◽

Atomic Time

AbstractRecent improvements in cesium and hydrogen terrestrial frequency standards have brought the frequency precision of International Atomic Time (TAI) to a value of 2.5E-15 s/s over an averaging time of a month. In this paper we illustrate the improvement graphically, and discuss the state of the art for frame ties between the radio, dynamical, and optical frames. In a larger paper, available via the World Wide Web, we illustrate the measured accuracy curves of the frequency standards, show their effect on the ensemble time scales, explain the reasons for the confusing array of available time scales, and discuss the inverse problem of using pulsar data to correct the terrestrial time scale.

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Current and future realizations of coordinate time scales

Proceedings of the International Astronomical Union ◽

10.1017/s1743921309990214 ◽

2009 ◽

Vol 5 (S261) ◽

pp. 95-101

Author(s):

E. Felicitas Arias

Keyword(s):

Time Scales ◽

Time Scale ◽

Proper Time ◽

Frequency Stability ◽

Reference Time ◽

Weights And Measures ◽

Coordinate Time ◽

Future Improvement ◽

Stability And Accuracy ◽

Atomic Time

AbstractTwo atomic time scales maintained at the International Bureau of Weights and Measures (BIPM) are realizations of terrestrial time: International Atomic Time (TAI) and TT(BIPM). They are calculated from atomic clocks realizing proper time in national laboratories. The algorithm for the calculation of TAI has been designed to optimize the frequency stability and accuracy of the time scale. Plans for the future improvement of the reference time scales are presented.

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Labors of the International Bureau of Weights and Measures

Scientific American ◽

10.1038/scientificamerican03081890-11821supp ◽

1890 ◽

Vol 29 (740supp) ◽

pp. 11821-11823

Keyword(s):

Weights And Measures ◽

International Bureau

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The long-term instability of the new generation hydrogen masers

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-1-35-38 ◽

2020 ◽

pp. 35-38

Author(s):

S.I. Donchenko ◽

I.Y. Blinov ◽

I.B. Norets ◽

Y.F. Smirnov ◽

A.A. Belyaev ◽

...

Keyword(s):

Time Scale ◽

Frequency Difference ◽

Clock Frequency ◽

Quantum Frequency ◽

Frequency Standards ◽

Quantum Frequency Standards ◽

New Generation ◽

Atomic Time

The latest changes in the algorithm for the formation of the international atomic time scale TAI are reported in terms of estimating the weights of the clocks involved in the formation of TAI. Studies of the characteristics of the long-term instability of new-generation hydrogen masers based on processing the results of the clock frequency difference with respect to TAI are performed. It has been confirmed that at present, new-generation hydrogen masers show significantly less long-term instability in comparison with quantum frequency standards ofsimilar and other types.

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GNSS-to-GNSS time offsets: study on the broadcast of a common reference time

GPS Solutions ◽

10.1007/s10291-020-01082-y ◽

2021 ◽

Vol 25 (2) ◽

Author(s):

Ilaria Sesia ◽

Giovanna Signorile ◽

Tung Thanh Thai ◽

Pascale Defraigne ◽

Patrizia Tavella

Keyword(s):

Time Scales ◽

Time Scale ◽

Reference Time ◽

Single Time ◽

Common Reference ◽

Prediction Quality ◽

Common Time ◽

Time Offset ◽

The Impact ◽

Low Uncertainty

AbstractWe present two different approaches to broadcasting information to retrieve the GNSS-to-GNSS time offsets needed by users of multi-GNSS signals. Both approaches rely on the broadcast of a single time offset of each GNSS time versus one common time scale instead of broadcasting the time offsets between each of the constellation pairs. The first common time scale is the average of the GNSS time scales, and the second time scale is the prediction of UTC already broadcast by the different systems. We show that the average GNSS time scale allows the estimation of the GNSS-to-GNSS time offset at the user level with the very low uncertainty of a few nanoseconds when the receivers at both the provider and user levels are fully calibrated. The use of broadcast UTC prediction as a common time scale has a slightly larger uncertainty, which depends on the broadcast UTC prediction quality, which could be improved in the future. This study focuses on the evaluation of two different common time scales, not considering the impact of receiver calibration, at the user and provider levels, which can nevertheless have an important impact on GNSS-to-GNSS time offset estimation.

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Update on a comparison of cesium fountain primary frequency standards

2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings ◽

10.1109/fcs.2011.5977749 ◽

2011 ◽

Cited By ~ 2

Author(s):

Thomas E. Parker

Keyword(s):

Frequency Standards ◽

Primary Frequency

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OPTICAL CLOCKS AND FREQUENCY METROLOGY FOR SPACE

International Journal of Modern Physics D ◽

10.1142/s0218271807011474 ◽

2007 ◽

Vol 16 (12b) ◽

pp. 2537-2540

Author(s):

HUGH KLEIN

Keyword(s):

European Space Agency ◽

Frequency Standard ◽

Optical Frequency ◽

Fundamental Physics ◽

Frequency Standards ◽

Space Agency ◽

Primary Frequency ◽

Measurement Capabilities ◽

Science Activities ◽

Frequency Metrology

Optical frequency standards and femtosecond comb measurement capabilities now rival and in some cases exceed those of microwave devices, with further improvements anticipated. Opportunities are emerging for the application of highly stable and accurate optical frequency devices to fundamental physics space science activities, and the European Space Agency (ESA) has recently commissioned studies on different aspects of optical clocks in space. This paper highlights some examples, including the difficulty of comparing very accurate terrestrial clocks at different locations due to fluctuations of the geoid; by locating a primary frequency standard in space, one could avoid geoid-related gravitational redshifts.

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