Know what time it is within a few nanoseconds. An even more accurate determination of the time may soon be possible, partly thanks to the atomic clocks of the navigation laboratory of the European Space Agency (ESA). ESA has commissioned the Dutch national metrology institute VSL and CGI to test whether the coordinated world time (UTC) from these accurate atomic clocks can be distributed through an fibre-optic connection to a tiny fraction of a second.
Metrology institutes and observation stations worldwide collect data from atomic clocks to determine the current UTC (Coordinated Universal Time). This coordinated world time plays an important role in our daily activities. We use this time, for example, in internet banking and aviation. The UTC is almost identical to UT1 (formally known as Greenwich Mean Time, GMT). But UT1 is a pure astronomical time, while the UTC is based on atomic clocks and coordinated with the rotation of the Earth. There is an extremely small difference between UT1 and UTC. To compensate for that, sometimes a leap second must be inserted.
The European Space Agency is one of the organisations that supplies data for the UTC and uses the atomic clocks of its own navigation laboratory for this purpose.These are used to support the development and validation of Galileo, the European Global Satellite Navigation System (GNSS) which is comparable to the American GPS system. Since the 14th of November, ESA has been using a test set-up for the Transnational Time Transfer (TripleT) project. Together with the network provider Eurofiber and timing technology provider OPNT, VSL and CGI have established a direct transnational fibre-optic connection between a UTC lab in Brussels and the UTC lab of the European space centre ESTEC in Noordwijk. The aim is to compare the time observations of GNSS in nanosecondes via this fibre-optic connection in a validation environment. The White Rabbit time transfer protocol is used. This leads to an optimal time transfer. The results of this validation will be used, among other things, for the definition of the second generation of Galileo (G2G).
The TripleT project is part of the European GNSS Evolutions Programme (EGEP) and is financed by ESA. Part of the project is a cloud-based dashboard developed in cooperation with CGI. This provides scientists with graphical insight into the status and performance of the equipment that can monitor time observations with a minimum delay. The first results are expected in the coming months.
The view expressed herein can in no way be taken to reflect the official opinion of the European Space Agency.