Michael A. Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz, E. de Carlos-Lopez
Time measurement is of great importance for science, technology and commerce. Among the seven base units of the International System (SI), the second can be realized with the smallest uncertainty, currently reaching parts in 1016. Keeping track of the continuous accumulation of seconds allows the formation of time scales that serve as references for applications that require synchronization to national and international standards. This paper presents and discusses an international time scale developed for the Sistema Interamericano de Metrologia (SIM) region. This time scale, known as the SIM Time Scale, or SIMT, was developed to complement the official world time scale, Coordinated Universal Time (UTC), by providing real time support to operational timing systems. SIMT is generated from automated comparisons of clocks in North, Central, and South America, and is believed to be the first international time scale whose results are made publicly available in real time.
IEEE Transactions on Instrumentation and Measurement