WRC-23 approves the adoption and implementation of Continuous Universal Time Coordinated UTC

The ITU World Radiocommunication Conference 2023 (WRC-23), held in Dubai, United Arab Emirates, from November 20 to December 15, 2023, approved the adoption and implementation of UTC Continuous Universal Time as the internationally recommended reference time scale. Successful negotiations focused on the importance of making UTC a continuous time scale, and on the revision of Resolution 655 (WRC-15) concerning the definition of a time scale and the broadcasting of time signals using radiocommunication systems. The main results include :

• Recognition of Resolution 2 of the 26th CGPM (2018) on the definition of UTC and Resolution 4 of the 27th CGPM (2022) on the use and future evolution of UTC. The latter aims to provide a continuous reference time scale for a century;
• Recognition of the results of studies carried out by Working Party 7A and published in Report ITU-R TF.2511, dealing with the various aspects of the current reference time scale and those that could be defined in the future, including their implications and applications;
• The continuation of the fruitful collaboration between the BIPM and the ITU-R, in preparation for the decision of the 28th meeting of the CGPM (2026) concerning the new maximum tolerance for UT1 – UTC and its date of application;
• The continuation the study of the content and structure of time signals to be broadcast using radiocommunication systems, including wireline technologies, using the combined technical expertise of the organizations concerned, in order to produce new and revised ITU-R reports and recommendations, including but not limited to a revised version of Recommendation ITU-R TF.460-6 on standard frequency and time signal emissions.

Contact LNE-SYRTE: Joseph Achkar <joseph.achkar@observatoiredeparis.psl.eu>
CEPT European Coordinator on UTC at WRC-23 and Chairman of ITU-R Working Group 7A