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

Since the 2014 annexation of Crimea, Russia has reportedly been blocking the GNSS signals beamed down to Ukraine, cutting the country off from position, navigation, and time services. Then, in 2017, 20 vessels 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] is bigger now, because of the geopolitical situation, which gives certain national actors a certain interest in disturbing GNSS,” Kohn explains. “So, if you have a critical application—meaning critical in the sense of national interest—I am doubtful that only relying on GNSS is a good answer.”

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

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

And because of its better reliability, the expectation is that RETSI will be “the source or heartbeat of a system of systems, or the core of the onion as it were,” Lobo says. Organizations that rely on resilient timing—banks, telecommunications companies, defense companies, as well as those that serve them—may switch to this system, but it’ll also accelerate innovation in new technologies, enabling companies to deliver new products and services. For instance, precise and robust timekeeping will be the foundation for technologies like 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 top of it,” says Schrock. “When you have a good backbone like this, it allows companies to better serve their customers.”

None of this is to say that what the NTC is doing is wholly unique, because there are other places in the world with comparable mesh networks of atomic clocks. Mostly, though, these exist at a local or even laboratory scale where GNSS isn’t reliable enough. For instance, Japan relies on a network of synchronized time centers because of the risk of earthquakes. There are similar networks in China, the US, and other countries, but those are “rarely promoted outside of the precise timing community and industry,” Schrock says.

The hope is that RETSI will launch in 2024, with basic free access available over the internet and the most highly assured, extreme accuracy offered over fiber cable. With the growing demand for increasingly precise time across various industries, Lobo believes that this could be the beginning of a major change in how we understand precision timing.

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

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