Satellites keep the world’s clocks on time. What if they fail?

Since the annexation of Crimea in 2014, Russia has reportedly blocked GNSS signals broadcast to Ukraine, cutting off the country from positioning, navigation and timing services. Then, in 2017, 20 ships in the Black Sea reported that their GNSS signals had been spoofed to indicate they were more than 20 miles inland, prompting reports that Russia was testing a new type of electronic warfare.

“The risk [of GNSS outages] is now larger due to the geopolitical situation, which gives certain national actors some interest in jamming GNSS,” explains Kohn. “So if you have a critical application — that is, critical in the sense of the national interest — I doubt that relying solely 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 consists of a network of atomic clocks housed in four secure facilities across the country, including Teddington. These generate a perfectly stable pulse, exactly one second long. This service is called Resilient Enhanced Time Scale Infrastructure (RETSI) and is available even if one of the sites fails. “The path to creating resilience is through diversity, each with different failure modes, rather than relying on one solution,” says Lobo.

From RETSI, the NTC will directly maintain a local time that is as accurate as the time currently provided by GNSS. It is distributed to essential services via radio signals, satellite constellations and fiber optic cables.

And because of its better reliability, RETSI is expected to be “the source or the heartbeat of a system of systems, or the core of the onion, so to speak,” says Lobo. Organizations that depend on resilient timing—banks, telecoms, defense contractors, and those who serve them—can migrate to this system, but it will also accelerate innovation in new technologies and enable companies to offer new products and services. For example, precise and robust time measurement will be the basis for technologies such as smart grids, smart cities and connected autonomous vehicles of the future.

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

None of this is to say that what the NTC is doing is entirely unique, as there are other places in the world with comparable mesh networks of atomic clocks. However, mostly these exist at local or even laboratory level where GNSS is not reliable enough. For example, 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 these “are rarely promoted outside of the precise timing community and industry,” says Schrock.

The hope is that RETSI will be introduced in 2024 with easy free access over the internet and the most highly secured, most extreme accuracy offered over fiber optic cable. With the growing demand for increasingly precise time across multiple industries, Lobo believes this could be the start of a major shift in our understanding of precision time.

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

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