Time – critical but vulnerable part of our total defence

Communication systems, power grids, positioning and navigation systems, financial transactions such as payments or stock exchange trading are examples of systems that depend on correct, accurate and traceable time and frequency.

“The importance has increased dramatically since the 90s. Mobile telephony requires that you can move between different base stations, which in turn means that the time needs to be synchronized between the base stations. Measurements in the electricity grid require that the electricity grid has the same "beat", i.e. synchronized frequency. All financial transactions are time stamped. Positioning and management of fleets for buses and transports requires accurate and traceable time, and the importance of this will only increase as vehicles and transports are automated. These are just a few examples, time is simply a prerequisite for much of what we take for granted today”, says Sven-Christian Ebenhag, senior researcher in position, navigation, and time.

The Swedish time scale is the foundation

An important part of securing our society's ability to deal with stress, crisis or war and ensuring that important functions in society can still operate is to be able to produce and disseminate accurate and traceable time without having to rely on other nations. At the National Laboratory for Time and Frequency, RISE is responsible for maintaining the Swedish national time, the UTC(SP) time scale, and for distributing it to actors who need accurate, traceable, and correct time.

“Our atomic clocks at RISE are the basis for the Swedish national time scale, but we have a system where, together with the Swedish Post and Telecom Authority, we have about 30 atomic clocks spread out in various places in the country which enable us to maintain our time scale even if the number of clocks would be reduced. We need to continue developing our ability, through long-term financing and by strengthening the physical protection around our facilities. But fundamentally there is a relatively robust system in place”, says Sven-Christian Ebenhag.

Many important functions of society rely on global navigation satellite systems (GNSS, such as GPS or European Galileo) to retrieve accurate time. The problem is that the signals from these systems are weak and very easy to jam, even with simple and cheap jammers that can be ordered online. With more powerful military equipment, it is possible to disrupt signals in much larger areas than that, as has been seen in Ukraine and in the Baltic Sea.

“GNSS is very good but we should not completely rely on GNSS as the only source of time”, says Sven-Christian Ebenhag.

More redundancy is required

The best way is to increase the redundancy, that is, to have multiple sources of traceable time that can step in if the main source is disrupted. For example, you can supplement with a solution where you get time from RISE or another actor through a fiber connection.
“Unfortunately, today this is lacking in many places. If the GNSS signals are disrupted in a shopping center, for example, it may become impossible to pay, because our payment systems require correct time stamps for the transactions”, says Sven-Christian Ebenhag.

The first step to create redundancy is for authorities, municipalities, companies, and other actors to map their dependence on GNSS and identify the areas that need improvement.

“Then each actor needs to ensure that they have access to the sources of accurate and traceable time that they need. There is also a need for a clear regulatory framework and an authority with supervisory responsibility for time and frequency, this is missing today even though it is a fundamental issue for our society's ability to function even under great stress”, says Sven-Christian Ebenhag.