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The SIM Time Network and its Contributions to Metrology in the Americas



Michael A. Lombardi


The SIM Time Network (SIMTN) has been one of the great success stories of the Sistema Interamericano de Metrologia (SIM), a regional metrology organization (RMO) that includes the 34 member nations of the Organization of American States (OAS). The SIMTN has made it easy for national metrology institutes (NMIs) throughout the SIM region to participate in international comparisons and to coordinate their time standards. It provides continuous, near real-time comparisons between SIM NMIs by utilizing both the Internet and the Global Positioning System (GPS). This article provides an overview of the SIMTN, examining both the technology involved, and some of its contributions to metrology in the Americas.
Metrologist: NCSLI Worldwide News


common-view GPS, international comparisons, time scale, traceability


Lombardi, M. (2009), The SIM Time Network and its Contributions to Metrology in the Americas, Metrologist: NCSLI Worldwide News, [online], (Accessed May 23, 2024)


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Created April 1, 2009, Updated February 19, 2017