National measurement standards / National Metrology Institute

Metrosert is the National Metrology Institute of Estonia. We maintain and develop Estonian national measurement standards for length, mass, temperature and electrical quantities. The quality of numerous Estonian products and services is based on our measuring capability.


Time and frequency

Accurate time and frequency measurements are the basis of many advanced technological solutions today, such as the 5G network or radar technologies. The accurate measurement of time is also important in services where the cost of the service depends on the duration of use of the service. Estonia currently lacks the capability to measure time and frequency at the level of a national measurement standard. The development of a national measurement standard of time and frequency is necessary for us to be able to ensure the capability of transmitting time independently of the external environment in the near future and to offer more support to companies whose services are already dependent on the accurate measurement of time.

The SI unit of time is the second, the symbol of which is s. Second is defined by taking the fixed numerical value of the caesium frequency ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s-1.

Metrosert’s development project for the national measurement standard of time and frequency lasts until the end of 2025. In the course of the project, a laboratory for the national measurement standard of time and frequency will be established, the core of which will be made up by caesium atom clocks.

The national objectives of developing the national measurement standard of time and frequency are:

  • To provide a traceable time service to customers
  • To be of support in the case of GNSS (the global satellite navigation system) disruptions
  • To support time, frequency and electricity measurements
  • To develop a frequency measurement service at Metrosert

Internationally, the goals of this project include:

  • Joining the international coordinated time (UTC) system

Implementing research and development projects in order to increase time and frequency related knowledge in Estonia


Mihkel Rähn

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