Realisation and dissemination of Swiss time

METAS is responsible for the realisation and dissemination of the official Swiss time, UTC(CH). With our atomic clocks, we make an important contribution to the generation of Coordinated Universal Time (UTC).

© METAS

Swiss time in everyday life

Navigating with your smartphone, communicating online or making cashless payments – many of our everyday activities only work thanks to precise time synchronisation.

METAS makes an important contribution by realising the official Swiss time. Our high-precision atomic clocks at METAS help ensure that Switzerland is part of Coordinated Universal Time (UTC). This ensures that technical systems in Switzerland and around the world work at the same pace, down to the smallest fraction of a second.

Typical applications

• Navigation (GPS): The exact time enables precise positioning of smartphones, navigation devices and vehicles.
• Telecommunications and Internet: Synchronised networks enable stable connections and fast data transmission.
• Financial systems: Exact time stamps safeguard the history of transactions and stock exchange trading.
• Transport and logistics: Timetables, air traffic and supply chains are coordinated.
• Electricity grids: Accurate synchronisation of complex electrical networks is required to ensure their efficiency and reliability.
• Quantum communication systems: The transmission of encrypted data via fibre optic networks is only possible if very precise synchronisation is available.

Our services

Realisation of Swiss time UTC(CH)

At METAS, we use state-of-the-art atomic clocks to record Swiss time UTC(CH) and its basic unit, the second, with the utmost accuracy.

Dissemination of Swiss time UTC(CH)

METAS disseminates the official Swiss time UTC(CH) via various technologies. Which solution is suitable depends primarily on the accuracy and reliability requirements:

• With METAS’s NTP time dissemination service (Network Time Protocol), computer clocks can be synchronised with the official Swiss time over the network. The achievable accuracy is in the range of a few dozens of milliseconds and is sufficient for many applications.
• The PTP time dissemination service (Precision Time Protocol) enables synchronisation accuracies of a few hundred nanoseconds.
• White Rabbit expands PTP and achieves accuracies of a few hundred picoseconds.

The time dissemination services PTP and White Rabbit are offered in conjunction with Switch.

Is the service you are looking for not listed on the website? Please do not hesitate to contact us so that we can work together to find a customised solution to your problem.

Measuring methods and technologies

Swiss atomic clocks

METAS operates an ensemble of atomic clocks consisting of caesium atomic clocks and hydrogen masers, which are used to realise the official Swiss time UTC(CH) and to compare it internationally with satellite connections. This results in a highly stable time scale. The accuracy of this time scale is achieved by the additional involvement of primary frequency standards, one of which METAS owns: the Fontaine Continue Suisse (FoCS-2). In doing so, METAS is contributing to the realisation of Coordinated Universal Time (UTC). Atomic clocks are carefully protected against external influences such as vibrations, temperature or humidity fluctuations.

• METAS primary frequency standard FoCS-2

  The METAS primary frequency standard FoCS-2 determines the second using caesium atoms cooled down to extremely low temperatures with laser beams. In a continuous beam, these atoms move through microwave activity, where their characteristic transition frequency is measured. FoCS-2 is one of the most accurate atomic clocks in the world: It would only deviate by a second after around 30 million years.

Time comparisons

To determine Coordinated Universal Time (UTC), atomic clocks must be compared with each other around the world. To that end, METAS uses various methods for transferring time and frequency signals:

• TWSTFT (Two-Way Satellite Time and Frequency Transfer)

  METAS operates a ground station for the Two-Way Satellite Time and Frequency Transfer (TWSTFT). Time and frequency signals are exchanged via geostationary satellites in order to compare Swiss atomic clocks directly with those of other national metrology institutes.

  This method is one of the most accurate methods for international time comparisons and achieves uncertainties in the range of about one nanosecond. It also represents METAS’s official connection to the international time scale UTC.

• GNSS-based comparisons

  In addition to TWSTFT, METAS uses global navigation satellite systems (GNSS) such as GPS.

  In the “Common View” method, two stations simultaneously monitor the same satellite and compare their local clocks with its signal. The time difference between the clocks can be determined from this data. In addition, METAS uses the “Precise Point Positioning” (PPP) method, which works with the same GPS data and, in particular, offers high short-term stability.

Distribution of high-precision optical frequencies through fibre optic networks

METAS distributes high-precision optical frequencies via phase-stabilised fibre optic networks. The reference frequency is generated by a stabilised laser and fed back to an atomic clock using an optical frequency comb. The frequency is transferred from the microwave to the optical range, which enables low-loss and continuous distribution and makes it possible to perform high-precision calibrations at remote locations. This technology plays a decisive role, especially for the international comparisons of optical watches that will serve to redefine the seconds in the future.

Quality and expertise

You can find information on the quality of our services on the “Integrated Management System” page.

Enquiry and contact

Laboratory Photonics, Time and Frequency
Federal Institute of Metrology METAS
Lindenweg 50
3003 Bern-Wabern

T [phone]
[e-mail]

More information

• Legal basis

  The official Swiss time is governed by the Federal Act on Metrology. It is based on Coordinated Universal Time (UTC) and is defined as Central European Time (CET = UTC + 1 hour). Between the last Sunday in March and the last Sunday in October, Central European Summer Time (CEST = UTC + 2 hours) applies and is applied in coordination with other European countries.

  • Federal Act of 17 June 2011 on Metrology (MetrA, SR 941.20)
  • Summer Time Ordinance (SR 941.299.1)