Time and Frequency


The SIM Time and Frequency Working Group, MWG 5, promotes collaboration between the time laboratories of the National Metrology Institutes and Designated Institutes located in the Americas (North, Central, and South America, and the Caribbean Islands), with the objective to strengthen their metrological capabilities to ensure the health, safety, security, fair trade and the scientific and technological development for the welfare of the inhabitants of our countries.

Time laboratories of MWG 5 provide traceability to the SI unit of time (second, s) through the participation in the Key Comparison that define UTC, and comparisons with other Time laboratories that are participating in UTC. Also, MWG 5 members provide a local time reference traceable to UTC to support their national productive process.

Members of MWG 5 work in the development of timescales, new optical standards, time transfer, high accuracy time transfer for the financial sector, emergent technologies and national time dissemination. As part of the collaboration, knowledge transfer and technical cooperation between MWG 5 members, they participate in the SIM Timescale, SIM Time Network and NTP Servers Comparison regional projects. Also every 2 years, MWG 5 members meet for group strategic planning and training sessions. Members of MWG 5 work:

  • To coordinate the Time and Frequency metrology in SIM region, seeking to improve the technical capabilities in the benefice of their inhabitants through meetings, workshops and training opportunities at various NMI/DI.
  • To promote the participation of SIM Time laboratories in MRA activities.
  • To work together and in harmony with the BIPM Time Department to encourage SIM Time laboratories to participate in UTC.
  • To cooperate with International Metrological Organizations and International Technical Organizations to harmonize and promote the use of UTC as the time reference for our nations.
  • To promote Time and Frequency metrology as part of and integral solution in the technological advance in our societies.


Chair: Diego Luna

INTI/Argentina;  [email protected]

Vice Chair: Liz Catherine Hernández ;

INM/Colombia; [email protected]


  • Contacts
    • [Should hyperlink to SIM Web Page for the official contacts from the NMI/DI´s in T&F]
  • Projects
    • [Should hyperlink to SIM Web Page for official projects in T&F]
    • SIM TFWG Web Page: SIM Time Network, SIM Timescale, SIM NTP comparison, national web clocks and more.
  • Events & Meetings
    • [Should hyperlink to SIM Web Page for the official events and meetings in T&F]
    • SIM TFWG Web Page (Meetings): Meetings, training session slides and group photos.
  • Annual Reports & Documents
    • [Should hyperlink to SIM Web Page for the official reports and documents in T&F]
    • SIM TFWG Web Page (Publications): Technical publications in MWG 5.
    • CCTF-WGMRA Guidelines: Documents published by the CCTF Working Group on the MRA for the participation and traceability to UTC and CMC services.
  • Strategy & Roadmaps
    • [Should hyperlink to SIM Web Page for the official strategy & roadmaps in SIM T&F]
    • CCTF Strategic plan: Strategic plan and associated documents.


BIPM useful links in time and frequency metrology:

NIST useful links in time and frequency metrology:

ITU useful link in time and frequency: