Saying the government must focus on “delivering an operational resilient positioning, navigation and timing (PNT) system for the United Kingdom as soon as we can,” the British Science Minister, Lord Patrick Vallance, announced several initiatives in his opening remarks to the Royal Institute of Navigation’s UK PNT Leadership Seminar on Nov. 20, 2024.

Among them was a funding increase for the National Physical Laboratory’s National Time Centre (NTC) project from £30 million ($38 million) to £62.7 million ($79 million) and a plan to have NTC and the first of the nation’s new eLoran towers at initial operating capability (IOC) by January of 2027.

Plans for all efforts beyond next year were necessarily “subject to spending review.”

Still, seminar attendees were gratified to hear the minister’s endorsement of the 10-point PNT policy framework published by the previous administration in 2023 and his commitment to operationalizing it with implemented systems.

Shabana Haque, Ph.D., head of the United Kingdom’s National PNT Office, also addressed the seminar and elaborated on the government’s actions to date and plans moving forward. She also discussed efforts toward developing quantum technologies and how all the capabilities would be incorporated into a coherent architecture.

Clocks

The United Kingdom recognizes time and timing as the most fundamental component of the PNT utility. Its NTC R&D program, run by the National Physical Laboratory (NPL), has been up and running since 2019. Its primary objective is to create “…a resilient UK national time infrastructure through the building and linking of a new atomic clock network distributed geographically in secure locations.”

Five years later, that program is coming to an end. Plans are in the works for the next phase of the NTC program, which includes developing a national timing infrastructure and supporting a new timing ecosystem — one that includes two-way satellite-time transfer (TWSTT), eLoran and the country’s legacy MSF radio time service. The industry will have a valuable role in the architecture of time distribution and providing value-added services while accessing highly resilient and well-authenticated core government time infrastructure.

As a result of NTC work to date, traceable time and frequency signals can now be accessed by industry and academia from three NPL nodes dispersed across the United Kingdom. They are at the University of Strathclyde in Scotland, the University of Cranfield in the Midlands and the University of Surrey in the south.

eLoran

eLoran also features prominently in the United Kingdom’s PNT plans. Britain operated Loran-C as part of the Northern European network until the end of 2015. For the last year of that, differential stations were deployed along the United Kingdom’s eastern coast and maritime operations based on eLoran were authorized.

On Jan. 1, 2015, and despite British pleas to the contrary, other northern European nations terminated Loran broadcasts in favor of Galileo. The United Kingdom has continued to operate its single eLoran transmitter as a national time signal. Plans call for additional transmitters to enable eLoran navigation across the nation and its adjacent waters within the next two years.

The UK government has been working with several partners to advance its understanding and plan for the implementation of an eLoran capability. Haque highlighted work with the European Space Agency’s NAVISP program, resulting in the British company Roke developing an eLoran antenna for handheld devices.

She also discussed integrating the NTC’s clock and fiber network with eLoran signals and developing GNSS/eLoran receivers.

Many were particularly interested in an “eLoran Effectiveness Report” that the government commissioned and received from the General Lighthouse Authority’s Research and Development (GRAD) team. GRAD has extensive experience with the technology, having operated and evaluated the differential eLoran system along Great Britain’s east coast.

In a related move that helped signal the United Kingdom’s commitment to the technology, the Ministry of Defence issued a Request for Information (RFI) in September 2024 about a deployable eLoran capability. The RFI indicated that the document was a prelude to an acquisition.

Quantum research

The United Kingdom has invested more than £1 billion ($1.3 million) into quantum research, which has the potential to contribute to PNT with better timekeeping and inertial and gravimetric sensing.

One aim of the quantum research program is to develop “…new navigation and timing systems to provide resilience and improved accuracy in the event of the denial of satellite systems.” A specific goal is to deploy quantum navigation systems, including clocks, on aircraft by 2030.

The program began in 2014 and has seen a significant increase in 2024 with the establishment of five quantum hubs nationwide. The hub at the University of Glasgow focuses on resilient PNT systems for national security and critical national infrastructure.

Policy and coordination

Minister Vallance and Haque also discussed two important non-technology themes.

The first was that the United Kingdom’s PNT office is fully funded, staffed, and very active. It was created last year as a cross-government effort and includes representation from the Ministry of Defence. In addition to pushing the nation’s PNT efforts forward, the office has been engaged with numerous other governments, including those of the United States, Canada, Australia, New Zealand, Europe, Japan and Korea.

Second, while the PNT initiatives are necessary for the nation’s resilience and security they will also be a source of economic benefits. This goes beyond enabling the British economy to function during local and potentially widespread GNSS disruption events. As the nation develops the technology stack to support its own resilient PNT architecture, along with enabling and supporting policies, resilient PNT devices and services will become marketable to others.

A sovereign PNT capability that can both stand on its own and cooperate with GNSS is becoming increasingly attractive to many nations. Being able to source such a capability from a respected and trusted ally such as Great Britain could make acquiring and implementing such a system much easier for many.

The UK Science Minister also praised the RIN’s work and publication of a series of tools to help explain PNT and the need for resilience to those outside the community. The tools also will help organizations evaluate their readiness for GNSS disruptions.

Available from the RIN’s Resilient PNT Portal, they are

• A PNT explainer that outlines risks from over-dependence on GNSS and provides links to other informative resources.
• A best practices “placemat” describing a “Prepare, Act, Recover” framework for PNT disruptions.
• A PNT resilience checklist for organizations to use to self-evaluate their risk from GNSS disruptions.

The RIN recommends PNT experts use these tools working with customers, suppliers, and partners and act as a “guiding hand.”

The RIN sees these all as a “phase 1 release.” Feedback on the tools is encouraged and should be sent to [email protected]. The RIN team is eager to know what works and what could be improved, as well as to receive suggestions for other efforts.

As a “learned society,” the RIN has a significant influence on government policy and direction. This was recognized by Lord Vallance, saying, “The Royal Institute has played a really important role in recent years to highlight the PNT opportunity and risk, to provide expertise, and to work with government on solutions.”

The RIN’s director, John Pottle, and RIN Fellows Ramsey Faragher, Guy Buesnel and Andy Proctor were all recognized during the seminar for their contributions to the organization’s resilient PNT efforts.

UK leading the west

While China is in the final stages of establishing a nationwide clock system integrated with eLoran and signals from space, and South Korea is following suit, the United Kingdom seems to be the only Western nation in the process of establishing a coherent and resilient national PNT systems-of-systems architecture.

Some nations have substantial fiber timing networks, Europe seems to be on the path to a timing backbone, and the United States has three eLoran transmitters on air. However, none have announced the type of integrated plans the UK has published.

When asked about this, one UK PNT technology and policy expert opined that his nation is so far ahead of Europe and the United States because “we are unencumbered by having our own GNSS.”

His idea is that GNSS involves a lot of time, effort and money. The kind of financial and emotional commitments needed for these huge projects makes it hard for many to come to grips with the limitations and vulnerabilities of GNSS and the need to implement complementary systems. Both government officials and GNSS industry lobbyists may tend to resist such efforts, he said.

Concerning the UK government’s investment in OneNav, he said it is still possible that the United Kingdom might also pursue a space-based capability. Rather than establishing the capability on its own, in his opinion, the government will be much more likely to look for a commercial subscription service.

“We will access GNSS when we can trust it, and may pay for other signals from space,” he said. “But we want a sovereign capability for the United Kingdom, and the future of resilient PNT is terrestrial.”

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