Published: Tuesday, 24 August 2021 09:46
Building a fullfledged satellite navigation system, on the same scale as Galileo or its American, Russian or Chinese counterparts, would cost billions of dollars and take years. Credit: SpaceNews/Adobe Stock/ESA
When it comes to satellite navigation, the British government has struggled to find its way over the last five years.
Those problems began with a June 2016 referendum, when a narrow majority voted in favor of the United Kingdom leaving the European Union. That triggered the long, complex process of Britain disentangling itself from the EU across a vast spectrum of activities, with the governments not completing the final Brexit deal until December 2020.
Among those issues was Galileo, the EU’s satellite navigation system. With the UK no longer an EU member, the British government would need an agreement with the EU — including, likely, some financial contribution — to both continue participation in the manufacturing of Galileo satellites as well as access the system’s secure signal, the Public Regulated Service (PRS). The EU has such “third country” agreements with Norway and Switzerland.
By November 2018, though, any hope of an agreement between London and Brussels died when Theresa May, the British prime minister at the time, announced that the UK would instead pursue its own satellite navigation system. “Given the [European] Commission’s decision to bar the UK from being fully involved in developing all aspects of Galileo, it is only right that we find alternatives,” she said.
That decision raised eyebrows both inside and outside Britain. Building a full-fledged satellite navigation system, on the same scale as Galileo or its American, Russian or Chinese counterparts, would cost billions of dollars and take years. Moreover, Britain has at least limited access to the Global Positioning System’s encrypted signals.
The British government nonetheless embarked on initial plans for a UK Global Navigation Satellite System (GNSS), allocating 92 million pounds ($127 million) for an 18-month study. That effort looked at satellite and ground system technologies needed to develop an independent navigation system.
That effort, though, ended in September 2020 with the British government deciding, in effect, it would not pursue a full-fledged satellite navigation constellation. It replaced the UK GNSS project with the Space-Based Positioning Navigation and Timing Programme, which would explore what the government called “new and alternative ways” to provide PNT services.
“Now is the time to drive this work further to look into wider, more innovative ways of delivering this important national capability,” Graham Turnock, chief executive of the UK Space Agency, said in the government’s announcement of the new program.
RESILIENCE THROUGH DIVERSITY
The impetus behind the new program is resilience. “Our critical national infrastructure is really not resilient enough” should existing satellite navigation services be disrupted, said Dean Thomas, chief engineer and joint technical director of the Space-Based Positioning Navigation and Timing Programme at the UK Space Agency. “There is a risk that loss of these services would result in a critical impact on our infrastructure.”
Moreover, Britain remains dependent on other satellite navigation services. “We are, it’s worth pointing out, the only permanent member of the UN Security Council that does not have access to its own national system,” he said in a presentation at a Royal Aeronautical Society conference in May. Britain is one of five permanent members, alongside China, France, Russia and the United States.
The new program is looking at how to provide that resilience without the cost of a full system. “This program was asked to look at more innovative solutions. Do we really want to do a system that looks very much like GPS or Galileo, or are there alternatives we can build or buy or get provided to us that would provide resilience through diversity?”
The program started with a request for information in October 2020, seeking ideas for alternative approaches to space-based PNT. The program then took those ideas, along with internal ones, and refined them into ones for further study. In parallel, the program is looking at models for operating those systems commercially, with varying degrees of government involvement.
Thomas said the government was keeping an open mind for how a satellite system would be set up, rather than just the conventional approach of satellites in medium Earth orbit broadcasting L-band signals. That included low Earth orbit constellations and using different frequencies.
Another alternative is breaking from the current paradigm of “one-way” ranging, where satellites broadcast signals that devices receive and use to calculate a position. The study is open to including two-way ranging, where devices not only receive signals but also transmit them.
Those technical issues are linked to a more fundamental tradeoff. “Do we want something that is very similar to existing systems, and thus easily adopted by both receiver manufacturers and end users?” he asked. “Or do we want a system that is very different from existing systems and perhaps provides resilience?”
The former approach, he argued, makes a new system more likely to be adopted, but also more likely to be vulnerable to the same threats that can disrupt existing satellite navigation systems. The latter approach, by contrast, could be more robust to such threats, but may only be used by those who require that resiliency.
In late May, the UK Space Agency issued study awards worth more than two million pounds to six companies to study aspects of proposed satellite navigation systems. Neither the agency nor the companies — Airbus, CGI, GMV NSL, Inmarsat, QinetiQ and Sirius Analysis — disclosed details of those studies, other than they will examine technical and cost issues associated satellite navigation systems.
Rajeev Suri, the chief executive of Inmarsat, endorsed the concept of a British satellite navigation system in a July 8 speech at the Space-Comm Expo conference in Farnborough, England. “It would increase resilience, reduce reliance on existing, aging, non-sovereign systems, support domestic jobs and innovation and help meet the requirements of our allies,” he said. “From our perspective it is absolutely indispensable to the country’s future.”
Thomas said the program plans to complete the studies and provide recommendations to the government in November. “There are no easy choices. This is going to be quite a complex exercise,” he cautioned. “It’s going to require some degree of compromising, one way or another.”
ONEWEB’S ROLE IN SATELLITE NAVIGATION
The company that has publicly been most closely linked to a British satellite navigation system is not one that received a study contract in May but instead one the British government has made a far larger investment in: OneWeb.
When the British government announced in July 2020 that it was spending $500 million to take OneWeb out of Chapter 11 bankruptcy protection, working in partnership with Indian telecom company Bharti Global, many in the space industry speculated that the government’s interest in OneWeb included potential use of the satellite constellation for PNT services.OneWeb launched a batch of 36 satellites July 1, completing coverage of Earth’s northern latitudes. Credit: OneWeb
The government, while not explicitly giving that rationale, didn’t exactly disabuse it, either. In its announcement of the deal, the British government noted the constellation would provide “enhanced broadband and other services” worldwide. In September, when announcing the new satellite navigation program, Business Secretary Alok Sharma mentioned “considering low orbiting satellites that could deliver considerable benefits to people and businesses right across the UK.”
OneWeb is, in fact, considering providing PNT services using its satellite constellation. “What we can deliver is really a byproduct of our communications payload,” said Massimiliano Ladovaz, chief technology officer of OneWeb. “We don’t need multibillion-dollar additional satellites to deliver such capability.”
That would start with timing services with the initial “Gen 1” satellites, which OneWeb is currently deploying. “Without changing anything on the satellites, we will be able to provide good timing accuracy,” he said.
They would be followed by Gen 2 satellites later in the decade that OneWeb argues can provide full navigation services. “It’s about providing a high availability, high accuracy positioning, navigation and timing service that is independent” of other satellite navigation services, he said.
Those services will use the same Kuband frequencies as the communications payload, rather than traditional L-band navigation services. “It will provide all the advantages of immunity from jamming and spoofing, and high resilience,” said Maurizio Vanotti, vice president of space infrastructure development and partnerships at OneWeb during a discussion of satellite constellations at a European astronomy conference July 2.
That approach poses challenges in terms of ground equipment, Ladovaz acknowledged. OneWeb proposes developing ground terminals that would provide both broadband connectivity and PNT services.
OneWeb sees itself augmenting, rather than replacing, other satellite navigation services. “We don’t want to be a replacement for GPS,” he said. “We are complementary and, for critical infrastructure where you need resiliency, a system like OneWeb is very important.”
That could fit well with the UK government’s desire for some degree of complementarity in any satellite navigation system it pursues, something Vanotti mentioned. “That was one of the key aspects associated with the interest of the UK government in becoming a partner of OneWeb.”
What happens after the Space-Based Positioning Navigation and Timing Programme delivers its recommendations late this year is not clear, and will likely depend on what it recommends, including cost and schedule estimates.
And yet, five years after the Brexit vote, the door is not permanently closed to Britain rejoining the Galileo program. While British government officials have not discussed the option to sign a third-country agreement with the EU, European officials say they would always be willing to resume discussions to allow the UK back into Galileo.
“The European Union is open to negotiate with the UK on its participation in EU space programs. The ball is in London, not here,” said Timo Pesonen, head of the Directorate-General for Defence Industry and Space of the European Commission, during a June 22 briefing about the EU’s space programs in Brussels. Such discussions are underway for continued British participation in the Copernicus Earth observation program.
“On Galileo, the European Union remains open to negotiate a PRS access agreement,” he added, “but, so far, the UK has not expressed any interest.”
This article originally appeared in the July 2021 issue of SpaceNews magazine.
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