Improved Performance, Remote Realization, And Accessibility Inter-American Metrology System (SIM) Time Scale

Abstract

The time and frequency metrology working group of the Inter-American Metrology System (SIM) maintains a number of time measurement systems that were designed to coordinate frequency control and timekeeping throughout the Americas. These systems compare the national time standards maintained by national metrology institutes (NMIs) in the SIM region. Currently, 19 NMIs participate in the SIM Time Network (SIMTN) and contribute to and/or utilize the SIM Time Scale (SIMT). This paper presents the main features of the SIMT algorithm and provides an evaluation of its recently improved performance. The paper also describes how five SIM NMIs currently maintain rubidium clocks as national time standards that are automatically adjusted to agree with SIMT. The paper concludes by discussing how the SIM frequency and time data can be easily accessed from any Internet device, including mobile devices such as tablets and smartphones.