Satellites Keep the World’s Clocks on Time. What if They Fail?

Since annexing Crimea in 2014, Russia has been blocking GNSS signals sent to Ukraine, cutting the country off from position, navigation and time services. Then in 2017, 20 ships in the Black Sea reported that their GNSS signals had been spoofed to indicate they were more than 32 kilometers inland, prompting reports that Russia was testing a new type of electronic warfare.

“The risk [of GNSS outages] it’s bigger now, because of the geopolitical situation, which gives certain national actors a certain interest in disrupting GNSS,” explains Kohn. “So if you have a critical application, meaning critical in the sense of national interest, I doubt that relying on GNSS alone is a good answer.”

The NTC’s solution for the UK is to establish a separate service that could serve as an alternative. The system includes a network of atomic clocks housed in four secure facilities across the country, including Teddington. These will generate a perfectly stable pulse, precisely one second long. This service will be known as Resilient Enhanced Time Scale Infrastructure (RETSI) and will be available even if one of the sites fails. “The route to building resilience is through diversity, each with different failure modes, rather than relying on one solution,” says Lobo.

From RETSI, the NTC will directly administer a local time that is as accurate as the time currently provided by the GNSS. It will be disseminated to key services via radio signals, satellite constellations and fiber cables.

And because of its better reliability, the expectation is that RETSI will be “the source or the heartbeat of a system of systems, or the core of the onion so to speak,” says Lobo. Organizations that rely on a resilient schedule (banks, telecommunications companies, defense companies, as well as those that service them) can switch to this system, but it will also accelerate innovation in new technologies, allowing companies to offer new products and services For example, accurate and robust timing will be the foundation of technologies such as smart grids, smart cities and connected autonomous vehicles of the future.

“You have a good Internet and you can put distributed applications on it. You have a good timing network and you can put distributed timing applications on it,” says Schrock. “When you have a good backbone like that, it allows companies to better serve their customers.”

None of this is to say that what the NTC is doing is totally unique, because there are other places in the world with comparable mesh networks of atomic clocks. However, they mostly exist on a local or even laboratory scale where GNSS is not reliable enough. For example, Japan relies on a network of synchronized time centers due to the risk of earthquakes. Similar networks exist in China, the United States and other countries, but “they are rarely promoted outside of the accurate weather community and industry,” says Schrock.

The hope is that RETSI will be launched in 2024, with basic free access available over the Internet and the highest and most extreme accuracy offered over fiber cable. With the growing demand for more and more accurate time in various industries, Lobo believes this could be the start of a major shift in the way we understand accurate time.

“We see time in the future as a real utility,” he says. “Like power, water and gas, it will be available at the wall, so you can use it with complete confidence and trust, for all your applications.”

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