Time
NPL is the UK's centre for precise time and frequency measurement.
We operate the group of atomic clocks that form the national time scale, known as UTC(NPL).
The time scale provides the reference for a range of services that disseminate the Time from NPL. These services include the MSF radio time signal, which synchronises a considerable number of radio-controlled clocks across the UK.
The clocks at NPL are compared with those at other national timing institutes and contribute to the international time scale using highly accurate time and frequency transfer methods. NPL is a world leader in the analysis of clock and time transfer data, and is making a key contribution to the development of the timing infrastructure of the Galileo satellite navigation system.
Find out more: What is the Time?
- The GAARDIAN project is developing a sensor that will gather information about the performance of navigation systems, such as GPS and eLoran.
- One of the main ways laboratories and scientific institutions can obtain time traceable back to UTC(NPL) is via Global Navigation Satellite Systems (GNSS) such as GPS. NPL also uses this technique to contribute to world time, UTC.
- The importance of a single time scale being accepted and used world-wide cannot be over-emphasised.
- The Time group is currently involved in producing timing algorithms for two Galileo contracts and on improving our own UK UTC(NPL) timescale.
Time sectors & applications
Why we need accurate timing, the leap second, and more...
- The MSF signal transmitted from Anthorn (in Cumbria) provides a signal strength in excess of 100 microvolts per metre at a distance of 1000 km. This level should be sufficient to allow the time and date code to be received without difficulty.
- NPL operates a time and frequency transfer service that provides its customers with greater accuracy and data integrity than other commercially available time and frequency traceability routes.
- The MSF 60 kHz standard-frequency and time signal is occasionally taken off-air to allow maintenance work on the masts and antennae at Anthorn Radio Station to be carried out in safety.
- The MSF radio signal is a dedicated time broadcast that provides an accurate and reliable source of UK civil time, based on the NPL time scale UTC(NPL). It is available 24 hours a day across the whole of the UK and beyond.
- The NPL Monthly Bulletins for time & frequency cover the three standard-frequency and time radio signals that are most widely used in the UK: the MSF 60 kHz standard-frequency and time signal, the 198 kHz long-wave transmission from Droitwich radio station and the GPS navigation satellite signals.
- Includes computer time and characterisation services, subscription to time bulletins and GPS-common view services.
- If the computer is to tell the time accurately it must set its internal clock regularly against a trusted external source of time, which must be both accurate and reliable. NPL offers two services that provide access to just such a source.
Time history
History of the first caesium atomic clock.
Time case studies
History of the first caesium atomic clock.