– the intergovernmental organization through which Member States act together
     on matters related to measurement science and measurement standards.
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CCTF Working Group on Two-Way Satellite Time and Frequency Transfer (CCTF-WGTWSTFT)

Terms of reference

  • to perform coordination activities related to TWSTFT between participating and prospective institutes,
  • to act as a point of contact for BIPM on TWSTFT matters,
  • to organize the operation of TWSTFT links to support the production of TAI,
  • to perform calibration campaigns to reduce the time link uncertainties between participating institutes,
  • to observe and review the needs for remote frequency and time comparisons of frequency standards and atomic time scales,
  • to establish and maintain dedicated TWSTFT links to support remote clock comparisons,
  • to identify future needs of remote clock comparisons,
  • to undertake research for the improvement of TWSTFT and
  • to follow and assess other techniques, including GNSS, optical fibers, optical satellite links which could be used for remote (optical) clock comparisons, and
  • together with BIPM, to foster the spread of information on technical achievements by suitable means, e.g. via BIPM webpage.
September 2012


  • Mr Victor Zhang  (NIST)


  • Dr Frédéric Meynadier  (BIPM)


  • The members of the working group are representatives and especially experts of the participating institutes as well as representatives of prospective participating institutes. Representatives of institutes interested in this field are encouraged to follow the activities as observers.

See the names of the members

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BIPM Workshop on Advanced Time & Frequency Transfer Techniques 2011