FUTURE OPTIONS FOR CIVIL TIMEKEEPING: UTC AND THE ALTERNATIVES

The 2012 Radiocommunication Assembly and World Radiocommunication Conference of the International Telecommunication Union recommended further studies concerning the future of UTC. Issues regarding UTC definition are not restricted to telecommunication, but have broad impacts scientifically, publicly, and legally. In response, various requirements, options, and issues are summarized, with one approach appearing to meet requirements and having consistency with current practices. This approach would officially sanction an atomic time scale with a constant offset from TAI, without leap seconds, for the users who require such a time scale, leaving the current definition of UTC unaltered. The additional scale might be realized by transmissions or services distinct from UTC, but it would be best realized as an encoded correction to UTC as currently defined. This latter approach is already recommended by ITU-R Recommendation TF.460-6.