The SIM Network: Improved Time Coordination for North, Central, and South America

Published

April 23, 2008

Author(s)

Jose M. Lopez, Michael A. Lombardi, Andrew Novick, Jean-Simon Boulanger, R. de Carvalho, R. Solis, Francisco Jimenez

Abstract

The Sistema Interamericano de Metrologia (SIM) consists of national metrology institutes (NMIs) located in the 34 member nations of the Organization of American States (OAS), which extends throughout North, Central, and South America, and the Caribbean region. SIM is one of the world s five major regional metrology organizations (RMOs) recognized by the Bureau International des Poids et Mesures (BIPM). Currently about half of the 34 member NMIs maintain time and frequency laboratories.  In order for these NMIs to establish metrological traceability and to determine the uncertainty of their measurements, it is important for each of them to participate in international comparisons. The SIM network was developed to advance the state of metrology in the SIM region and to allow as many laboratories as possible to participate in international time coordination.  It provides continuous, near real-time comparisons between the national time and frequency standards located throughout the SIM region, by utilizing the technology of both the Internet and the Global Positioning System (GPS).  As of early 2008, ten SIM NMIs have are participating in the SIM network, and six additional NMIs are expected to be added to the network as soon as resources become available.  The paper provides an overview of SIM and a technical description of the network.  It also discusses the network s measurement uncertainties and presents results obtained from ongoing interlaboratory comparisons.

Proceedings Title

Proc. 2008 EFTF Conf.

Conference Dates

April 23-25, 2008

Conference Location

Toulouse, 1, FR

Conference Title

2008 European Frequency and Time Forum

Pub Type

Conferences

Download Paper

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Keywords

common-view, GPS, metrology, time transfer, traceability

Citation

Lopez, J. , Lombardi, M. , Novick, A. , Boulanger, J. , de Carvalho, R. , Solis, R. and Jimenez, F. (2008), The SIM Network:  Improved Time Coordination for North, Central, and South America, Proc. 2008 EFTF Conf., Toulouse, 1, FR, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=842418 (Accessed October 9, 2025)