Proposals for Updating Tai Algorithm

摘要

The conditions of computation of TAI and UTC are in constant evolution. The replacement of clocks of older design by new ones of type HP 5071A, started in 1993, continues with consequent improvement in the stability of the free atomic time scale EAL, the first step in the calculation of TAI. To further improve the stability of EAL and to further reduce the delay of access to TAI and UTC, the algorithm which produces them may need to be revised. With this in view, experiments on real clock data collected at the BIPM have been carried out to show the advantage of simultaneously using an upper limit on relative weights, rather then one on absolute weights, and a basic interval of computation of one month, rather than one of two months. Results of these tests are positive, so the BIPM reported on these studies to the Working Group on TAI of the Comite Consultatif du Temps et des Frequences' (CCTF) in view of implementing consequent changes in January 1998. A decision is being made.