CCTF

Committee title

Consultative Committee for Time and Frequency (CCTF)

CGPM-2026 CCTF report

28th meeting of the CGPM

Report of the CCTF to the CGPM

Read the report of the Consultative Committee for Time and Frequency (CCTF) to the 28th meeting of the General Conference on Weights and Measures (CGPM).

Read the CCTF report →

President

Dr N. Dimarcq

CNRS Senior Scientist at ARTEMIS

CNRS, Université Côte d'Azur, Observatoire Côte d'Azur

France

Executive Secretary

Dr P. Tavella

Bureau international des poids et mesures

France

ALL MEMBERS

List of meetings

Meetings and related documents

Past Meeting

24th meeting of the CCTF (Session II - BIPM Headquarters (Sèvres))
  • From 18 to 19
  • September
  • 2025

Past Meeting

24th meeting of the CCTF (Session I - online)
  • 14, 15, 21, 22 November
  • 2024

Past Meeting

23rd meeting of the CCTF (online)
  • From 29 June
  • to 01 July
  • 2022

Past Meeting

22nd meeting of the CCTF (Session II - online)
  • From 11 to 12
  • March
  • 2021
All meetings

CCTF Hot topics

Hot topics currently under discussion at the CCTF (public documents)

Redefinition of the second

Continuous UTC

Moon Timing

Asset Publisher

Working Groups

CCL-CCTF-WGFS

CCL-CCTF Working Group on Frequency Standards

CCTF-WGATFT

CCTF Working Group on Coordination of the Development of Advanced Time and Frequency Transfer Techniques

CCTF-WGGNSS

CCTF Working Group on GNSS Time Transfer

CCTF-WGMRA

CCTF Working Group on the CIPM MRA

CCTF-WGPSFS

CCTF Working Group on Primary and Secondary Frequency Standards

CCTF-WGSP

CCTF Working Group on Strategic Planning

CCTF-WGTAI

CCTF Working Group on TAI

CCTF-WGTWSTFT

CCTF Working Group on Two-Way Satellite Time and Frequency Transfer

WG-SP Task Groups BUTTON

Publications

Publications

Strategy documents

[CCTF] CCTF Strategy

Guidance documents on the CIPM MRA

[CCTF] TF - CCTF-WGMRA Guideline 1: The Service Category classification system for T&F CMC entries (2025)

[CCTF] CCTF Guidelines for Planning, Organizing, Conducting and Reporting Key, Supplementary and Pilot Comparisons

[CCTF] CCTF-WGMRA Guideline 6: Requirements for participation in the computation of UTC at the BIPM (2017)

All publications

CCTF-mission

Mission

The Consultative Committee for the Definition of the Second (CCDS) was set up in 1956. Its name was changed to Consultative Committee for Time and Frequency (CCTF) by the CIPM in 1997.

Present activities concern matters related to the definition and realization of the second, establishment and diffusion of International Atomic Time (TAI) and Coordinated Universal Time (UTC), and advice to the CIPM on matters related to time and time scales.

Nested Applications

News and Updates

BIPM150 Interview: Prof. Hidetoshi Katori on the Future of Optical Lattice Clocks

Follow along as Prof. Hidetoshi Katori speaks to the BIPM about how optical lattice clocks have opened a path to accuracy at the level of 10⁻¹⁸ and the opportunities this opens up.

BIPM150 Interview: Dr Marina Gertsvolf on Overcoming Challenges on the Road to Redefining the Second

Follow along as Dr Marina Gertsvolf speaks to the BIPM about  the progress and challenges faced by the Consultative Committee for Time and Frequency (CCTF) in preparing for a future redefinition of the second.

BIPM150 Interview: Javier Benedicto on Timekeeping for Satellites Systems and Space Exploration

Follow along as Dr Javier Benedicto speaks to the BIPM about why metrology underpins all space programmes — from Earth observation and telecommunications to planetary exploration.

Asset Publisher

Reports and announcements

Report of Session II of the 115th meeting of the CIPM (2026)

Annual Review Supplement - Activities of the BIPM Departments 2025

BIPM Annual Review 2025

Report of Session I of the 115th meeting of the CIPM (2026)

Report of the 114th meeting of the CIPM (2025)

Enhancing the UTCr algorithm: performance improvements and optimization

CIPM Strategy 2030+

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