We have our own representation of UTC: UTC(DFM).
Accurate time definition is extremely critical in many industries such as telecommunications and finance. A typical application can be, for example, precise time stamping of financial transactions.
In Denmark, we have not yet had our own calibrated atomic clock, so we have been dependent on other countries’ time references. In day-to-day life, this is not necessarily a problem, as with a satellite receiver you can get an accurate time from satellite navigation systems like GPS, which are based on precise atomic clocks.
The problem arises in the event of a Global Navigation Satellite Systems (GNSS) outage, which would be critical for sectors that rely on accurate time stamps. This was pointed out in a report prepared by consultancy London Economics for the Interdepartmental Space Committee in 2019.
In early 2021, DFM received a grant from the Ministry of Higher Education and Science to establish a national time reference and link it directly to UTC time. UTC stands for Coordinated Universal Time and is used all over the world.
In February 2021, DFM received an atomic clock from the Swiss company T4 Science. The atomic clock is a Maser (Microwave amplification by stimulated emission of radiation), which is based on the frequency of the electromagnetic radiation emitted when a Hydrogen atom changes state between two very specific energy levels. At one energy level, the spin of the proton and electron are in the same direction, and at the other energy level, the spin is in opposite directions. Specifically, radiation at 1,420,405,751.768 Hz, corresponding to a wavelength of about 21 cm, is emitted at the transition between these two energy levels.
Senior researcher Jürgen Appel, who was responsible for the installation and commissioning of the hydrogen meter, spent about 6 months investigating the stability and accuracy of the hydrogen meter, which now follows UTC time
The Danish UTC representation has also been included in the Bureau International des Poids et Mesures (BIPM) list of time references and DFM reports monthly to BIPM, so that the Danish time measurement is included in the global definition of time.
Although a real-time approximation of UTC(DFM) is now available in Denmark and can be used in the future by anyone who needs a very precise time reference, it is not actually the official time in Denmark. According to the current legislation from 1893, it is the “Mean Solar Time for the 15th Longitude East of Greenwich” that officially defines the time in Denmark. Therefore, a change in the law is needed for UTC+1 to become the official time in Denmark.