Although most people don’t think about it, precise time is a very important part of our lives. Whenever we make a phone call, use mobile internet, or rely on navigation, we depend on systems that are synchronised to a very precise time. Precise time synchronisation is used not only in telecommunications, but also in the energy sector, the financial sector, defense, and research. In some cases, accuracy to the second or even the millisecond is not enough – precision down to microseconds and sometimes even nanoseconds is required.
How networks, power plants, and laboratories are synchronised
Today, satellite navigation systems, such as GPS or Galileo, are very often used to distribute precise time. In addition to determining location, they also provide highly accurate time information, which serves as a reference source for a wide range of technologies. It is precisely this information that is used to synchronize mobile networks, power systems, scientific instruments, and other infrastructure.
When GPS alone is not reliable
However, satellite navigation systems may not be reliable under all circumstances. Their signal can be jammed, intentionally distorted, and in some situations may be unavailable altogether. Events related to the armed conflict in Ukraine have shown that jamming of satellite navigation systems is not just a theoretical threat. Governments and operators of critical systems are therefore actively seeking alternative ways to ensure reliable time synchronisation for their critical infrastructure.
Optical fiber doesn’t just transmit data
One option is to use optical fibers, which most people associate with high-speed internet connections. These provide an independent path for distributing precise time and help reduce dependence on satellite navigation systems. For applications with high demands on reliability, they can thus serve as an important backup or supplementary infrastructure. However, the same infrastructure can also be used to transmit highly precise time and frequency information. Thanks to the CESNET consortium, an infrastructure is being developed for the distribution of precise time via optical networks. The project will include approximately twenty nodes equipped with White Rabbit technology.
White Rabbit: accuracy in the order of nanoseconds
White Rabbit technology was developed at CERN, where there was a need to synchronise large-scale scientific experiments with extremely high accuracy requirements. Compared to conventional methods, it can ensure synchronisation with an accuracy better than one nanosecond and maintain it even over long distances. This makes it suitable for scientific experiments, advanced measurement systems, and the development of a resilient time distribution infrastructure.
We verified the technology’s functionality not only under laboratory conditions but also in a real-world network infrastructure. Tests on routes spanning hundreds of kilometres confirmed that sub-nanosecond synchronisation can be maintained even during the simultaneous operation of high-capacity data services. Building on these verified results, we are now developing an infrastructure for the distribution of precise time within the CESNET network.
CESNET as a member of the White Rabbit Collaboration
Another significant step toward the further development of this technology is the White Rabbit Collaboration, an international platform founded by CERN. This year, CESNET became its first and, so far, only Czech member. The platform coordinates the further development of White Rabbit technology and brings together organisations involved in its development. Thanks to this membership, experts from the CESNET association will be part of this collaboration and will contribute to the further development of the technology.
