On optimizing the configuration of time-transfer links used to generate TAI

Recent work on the uncertainties of [UTC-UTC(k)] has made it possible to quantify the effects of different configurations of the time-transfer links used to generate International Atomic Time (TAI). The optimal topology depends upon the magnitude and character of the time-transfer noise of the relevant systems, the correlations between the time-transfer links, the required degree of robustness, the operational practices and equipment at pivot and crossover sites, and the operational complexity of generating TAI on a routine basis. The authors are members of a study group of the Consultative Committee for Time and Frequency (CCTF) Working Group on TAI that is studying these issues, and this paper will present considerations relevant to the problem.