QinetiQ-led Team Elaris has been awarded a £6 million contract with the UK Ministry of Defence (MOD) to develop a deployable solution concept for enhanced long-range navigation (eLoran).
Work completed under the two-year Urgent Compass program will be used to inform future demonstration, production and deployment packages of work.
The UK and its allies rely heavily on position, navigation and timing (PNT) for effective military operations. PNT solutions traditionally use GNSS signals, but these can be jammed or spoofed by adversaries in battlefield environments. A jammed or spoofed satellite navigation signal, if undetected or uncorrected, can result in misdirected troop movements or incorrectly guided missile trajectories, leading to mission failure in the battlefield arena.
Militaries are increasingly looking for alternative, more resilient PNT solutions to enhance and complement traditional GNSS, such as eLoran which is a terrestrially based alternative and can operate when access to satellite PNT is denied. This program extends QinetiQ’s engagement with MOD on assured PNT solutions, which includes the Robust Global Navigation System (RGNS) program — another key component in UK MOD’s approach to resilient PNT.
Urgent Compass will explore eLoran based solutions that can be quickly deployed into contested locations worldwide.
Team Elaris is made up of QinetiQ, UrsaNav, Roke and GMV. Each organization brings technical knowledge and domain expertise in PNT technologies to the partnership, which is exploring both deployable and fixed eLoran solutions.
GMV is leading the development of a secure two-way satellite time and frequency transfer system under the European Space Agency’s TOUCAN project.
The initiative safeguards critical infrastructure by reducing reliance on GNSS and enhancing national positioning, navigation and timing (PNT) capabilities. Funded by the UK Space Agency through its membership in ESA’s Navigation Innovation and Support Program (NAVISP), the project is an important part of the UK Government’s Framework for Greater PNT Resilience.
Through a competitive process, GMV was selected to enhance the UK’s national capabilities in delivering nationally assured, secure and continuous PNT services for critical infrastructure, defense and the broader economy.
TOUCAN, the two-way satellite time and frequency transfer capability demonstration (TWSTFT), will draw on GMV’s expertise in time transfer and system-level engineering, reinforcing the company’s role in supporting the government’s PNT resilience efforts.
“ TOUCAN represents a strategic milestone for GMV. It underscores our commitment to delivering cutting-edge, nationally assured, PNT solutions that are vital to the UK’s critical infrastructure and national security,” said Mark Dumville, general manager of GMV in the UK.
eLoran support
TOUCAN complements efforts to reestablish a UK eLoran system, which will serve as a terrestrial backup to satellite-based services. A critical goal is to ensure that this system operates independently of the more vulnerable GNSS.
The project’s primary objective is to establish an accurate, independently verifiable TWSTFT link between the eLoran transmitter and the National Physical Laboratory (NPL), the UK’s official timekeeping authority. The new link will address GNSS-dependence within eLoran, maintaining a time traceable to UTC (NPL).
In addition, the system will provide a TWSTFT connection to a facility that operates an R&D timescale, a secure reference that will one day be essential for synchronizing operations, maintaining communication integrity, and supporting mission-critical systems.
“Precise and secure timing is at the heart of so much we rely on every day, from banking and transport to energy and communications,” said Paul Bate, CEO of the UK Space Agency. “This investment in UK satellite timing through TOUCAN is about more than technology; it’s about protecting the everyday services people and businesses depend on. By working with GMV, the PNT Office and ESA’s NAVIS program, we’re helping to build a stronger, more resilient space ecosystem that safeguards our security and keeps the UK at the forefront of innovation.
GMV is delivering the design, integration and operational demonstration of the system, building on its proven track record in delivering secure national timing products and infrastructure. Project partner Viasat is supplying satellite bandwidth, as well as supporting GMV in analyzing innovative TWSTFT technology evolutions.
The UK Hydrographic Office (UKHO) hosted the UK’s first cross-government geodesy, positioning, navigation and timing working group in October. Representatives from 19 government bodies shared insight on the risks, opportunities and interdependencies linked to PNT systems, including GNSS.
On Nov. 19, the UK announced a £155M investment in PNT. The working group will continue to support collaboration and exchange knowledge as further resilience actions progress, according to the UKHO.
GNSS supports critical activities across the UK economy. It provides accurate location and timing for communications, maritime and aviation safety, and the smooth running of power and financial networks. As threats to space-based systems grow, improving national resilience is increasingly important.
“The UKHO’s expertise in geodesy plays a key role in helping the UK understand and protect PNT services. Our specialists provide trusted positioning and timing advice across defense and civil programs, including supporting the safety of navigation in UK waters,” the agency said.
“It is fantastic to hear that the work with eLoran, GNSS Interference Monitoring Programme, Space Based Time Transfer and the National Timing Centre have received ongoing funding,” said Joe Pearce, senior geodesy and PNT specialist, UKHO. “This funding will assist both our data collection and the mariner. It will protect and assist future geodesy and PNT, improving resilience as these systems come increasingly under threat.”
In recent years, hostile actors have jammed or spoofed PNT services, demonstrating potential threats to key services. PNT can also be affected by natural events like solar flares from the sun.
The £155 million funding was announced Wednesday by Science Minister Lord Vallance at the Royal Institute of Navigation’s annual PNT Leadership Seminar, which brings together researchers, innovators and business leaders from across the sector.
The investment includes initial work to provide PNT that is independent of signals from satellites, making it harder to jam or spoof; PNT resilience at the National Physical Laboratory; and a new system to proactively monitor for threats to the UK’s PNT services.
The £155 million funding consists of:
£71 million to begin work on a UK National Enhanced Long-Range Navigation (eLoran) program, providing PNT across land, air and sea independent of signals from satellites, and hard to jam or spoof.
£68 million for further development of the National Timing Centre (NTC) program. The NTC is being delivered by the National Physical Laboratory to develop the UK’s first nationally distributed time infrastructure. As well as boosting resilience, it could help with innovative new uses of technologies like 5G, satellite communications, and self-driving vehicles.
£13 million for work on a UK GNSS interference monitoring program, to deliver a world-leading capability for the UK to monitor and react to threats to PNT signals, like jamming and spoofing.
£3 million for the Space-Based Time Transfer R&D program. This will develop the technology required to deliver global timing systems independent of GPS and other GNSS.
“Having resilient and enduring access to Position, Navigation and Timing Services is a critical part of life in today’s world, and a major plank in the UK’s national security,” Vallance said. “So many of the things we take for granted every day, from using our phones to planning a journey, simply couldn’t happen without it. The UK is a leader in this field, but in an uncertain world we cannot be complacent. The funding we are announcing today will ultimately help protect Britain from the risks posed to PNT, from both accidental outages and hostile acts, safeguarding everyone’s wealth and wellbeing.”
“Strengthening the UK’s PNT capabilities will give direction to our growing PNT industry, supporting the wider economy and national renewal, whilst cementing the UK’s position as a global PNT leader,” Vallance said.
Today’s news comes after a substantial year of progress for UK PNT. The government agreed to closer work with both the US and France around PNT resilience, as part of September’s UK-US Technology Prosperity Deal and July’s UK-France Summit.
DSIT published a Call for Evidence on PNT growth in June, seeking views on the PNT market and R&D landscape in the UK, as well as the barriers to market entry, commercialisation, and user adoption. We will publish a summary of our findings later this year.
Over time, GPS dependencies have become deeply embedded in much of the nation’s critical infrastructure, as shown in Figure 1 — from emergency services and transportation systems to critical manufacturing and logistics operations. For the past 20 years, however, efforts to protect these assets with a true backup system have stalled, despite the establishment of the U.S. Space-Based Positioning, Navigation and Timing (PNT) Policy in December 2004.
With the recent Notice of Inquiry from the U.S. Federal Communications Commission (FCC), an updated list of technological options is now on the table. However, most would require building new infrastructure or rely on quantum-based technologies that are still years away from being practical or available.
U.S. GPS Efforts Separating
Since its inception in 1977, GPS has drawn from a single technology to serve civil and military sectors. Now, with space — particularly satellites — becoming physically contested in wartime scenarios, the military is embarking on its own approach. This includes pairing GPS with military- grade receivers to improve service and protection for the global GPS layer. And two new layers are being developed as part of a multi-layer approach, deemed the “regional” GPS layer (i.e., per country) and the “local” GPS layer (i.e., per metro).
Yet, with this new system — although supporting modular, open-systems integration — the Department of Defense (DOD) is now distancing itself from other future endeavors, including supporting civil critical infrastructure. The future DOD PNT system will not follow the same path to civil/military use as was taken by GPS. The PNT capabilities employed by the DOD as such will be increasingly classified. The civil effort has not only been left to fend for itself, but it also has been tragically fragmented across many federal departments and agencies. We can only hope the recent FCC focus will help to solidify the civil GPS efforts.
Doors Open for New Solutions
The new orientation of the civil approach opens the door to significant focus on local and regional GPS services. Specifically, a new approach is based on data from the Earth’s “RF geospatial layer,” where geospatial is “relating to or denoting data that is associated with a particular location.” This layer’s data is about available RF signals, which can be used to derive the location of a particular end device anywhere in the blanket of signals. Devices using this new approach will be unencumbered by the intricacies and costs of satellite technology or having to be joint solutions required to meet military standards.
This also opens the door to the power of solutions available through consortia, which can tap into an order of magnitude more benefits through hearty partnerships. All of which also leads to the much-needed speed-to-market.
The Biggest Advantage
In the U.S., more than 110,000 towers transmit a variety of RF signals available to derive PNT. These towers provide a wide range of three-tower geometries needed for PNT calculations and enable strong resiliency (as an adversary cannot disable them all).
Two systems, in particular, are worthy of close consideration. The broadcast industry’s proposed Broadcast Positioning System (BPS) uses ATSC 3.0 infrastructure along with the existing MerlinTPS adaptive RF signal system. Both these systems take advantage of existing RF infrastructure prevalent in most developed and developing countries.
Don’t Fall Into the eLoran Trap
eLoran has been suggested by some as a viable alternative used for deriving PNT. However, this technology has notable shortcomings. The portion of the RF band it uses has several limitations. For example, eLoran is based on a 100 kHz signal, a low-frequency band that is highly susceptible to atmospheric noise.
Although some propose the use of existing AM towers for the eLoran signal, most are ~300 ft, of which eLoran tends to operate with 1600 ft towers. Attempts to operate eLoran using these shorter towers will make for reduced efficiency. Another misconception is about the proposed use of existing AM tower guidewires for transmission. At these wavelengths, that would restrict the towers to be 900 miles apart, having an impact on maintenance.
eLoran would require building new infrastructure for U.S. deployment, including 12 new towers and transmitters. The number of installations requiring significant maintenance and this low number can be taken out in physical warfare.
The eLoran system requires tight synchronization of the signals between each of its towers and the national epoch, requiring additional infrastructure with its attendant maintenance. eLoran supporting position accuracy is rated at 10 m to 20 m CEP, which is not within the FCC requirement of less than 3 m CEP.
Timing accuracy is +/- 50 ns, which meets today’s precision needs, although it is quickly becoming inadequate as needs in the precision timing market continue to increase.
Finally, the eLoran service is transmitted on one known frequency and in a published format, making it more vulnerable to jamming.
GPS RF Systems Pack a Punch
Given the issues associated with eLoran, other technologies must be considered. One such technology is available today and provided by a commercial company, MerlinTPS, which can transfer market-available, precise timing down to +/- 10ns. Such as precise timing provided by another commercial entity, Hoptroff, for example. Both companies currently provide the necessary components of a viable terrestrial GPS.
As a consortium, MerlinTPS/Hoptroff could deliver precise timing wirelessly to broadcast TV towers for BPS, while eliminating the need for signal conditioning and additional synchronization equipment at each tower, or any other related infrastructure.
MerlinTPS combined with BPS could provide all GPS services for primary and backup (not just timing). MerlinTPS can also fill in services for BPS edge cases having poor geometries. These services include portable and mobile devices. MerlinTPS is also able to handle both the enterprise and civil approaches similarly.
New open doors create freedom to quickly address the urgent national security need for reliable, alternative PNT. The consortium approach, adding commercially available technology to the broadcast infrastructure, allows for collaborative development while preserving individual market opportunities, making it an attractive proposition for all participants.
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.
Photo: RNT Foundation
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.
UrsaNav Loran monitor on Nautel equipment. (Photo: RNT Foundation)
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 billion) 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.
USCG Loran tower circa 1995. (Photo: RNT Foundation)
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.”
Among them was a funding increase for the National Physical Laboratory’s National Time Centre (NTC) project, from £30 million to £62.7 million, and a plan to have NTC and the first of the nation’s new eLoran towers at initial operating capability by January of 2027.
Plans for all efforts beyond next year were necessarily caveated with “subject to spending review.”
Still, seminar attendees were gratified to hear the minister endorse the ten-point PNT policy framework published by the previous administration in 2023. It was particularly encouraging that he also committed to operationalizing it with implemented systems.
The minister did not mention the UK’s significant investment in quantum research, which was discussed later in the seminar. This research has the potential to contribute to PNT with better timekeeping and inertial and gravimetric sensing. Three quantum hubs — one each in Scotland, the Midlands and the South — are part of this effort.
Lord Vallance, UK Science Minister. (Image: 10 Dowing Street)
Lord Vallance and Shabana Haque, Ph.D., the head of the National PNT Office, who spoke later, also mentioned two important non-technology themes.
The first theme was that the PNT office is fully funded, staffed and very active. It was created last year as a cross-government effort and included 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.
Secondly, the PNT initiatives are necessary for the nation’s resilience and security but will also be a source of economic benefits. This goes beyond PNT resilience, enabling Britain’s 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, devices and services will become marketable to others.
Shabana Haque, Ph.D., head of the UK PNT Office, spoke to the RIN at its 2024 UK PNT Leadership Seminar. (Image: RIN)
A sovereign PNT capability that can both stand independently 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 government has been working with several partners to advance its understanding and planning implementation of an eLoran capability. Haque highlighted work with the ESA’s F)!NAVISP program, resulting in the UK’s Roke developing an eLoran antenna for handheld devices. She also discussed the integration of the National Timing Centre’s clock and fiber network with eLoran signals and the development of GNSS/eLoran receivers. Of particular interest to many was an “eLoran Effectiveness Report” that the government commissioned and received from the General Lighthouse Authority’s Research and Development (GRAD) team. GRAD has had extensive experience with the technology, having operated and evaluated a differential eLoran system along Britain’s east coast for more than a year.
In a related move that helped signal the UK’s commitment to the technology, the Ministry of Defence issued a request for information (RFI) about a deployable eLoran capability in September. The RFI indicated that the document was a prelude to an acquisition.
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 will also help organizations evaluate their readiness for GNSS disruptions.
A PNT Resilience Checklist for organizations to use to self-evaluate their risk from GNSS disruptions.
The RIN recommends that PNT experts use these tools to work 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 say they are eager to know what works, what could be improved, and to receive suggestions for other efforts.
As a “learned society,” the RIN has a significant influence on government policy and direction. Lord Vallance recognized this, saying that “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.
Commercial eLoran to be offered in the UK
Hellen Systems, Inc. and Arqiva have partnered to develop a commercial eLoran service in the United Kingdom. The announcement was made on the Hellen Systems LinkedIn page.
The partners seek to support critical national infrastructure, government, and military users by citing the need for “sovereign, independent, resilient” PNT alternatives.
eLoran is deployed and operating across China and South Korea. Older versions of Loran are operating in Russia and Saudi Arabia. Yet, aside from a single transmitter in the UK being used as a timing signal, operating Loran systems have been off the air in the West since the European system shut down in deference to Galileo in 2016.
In recent years, increasing interference with GNSS signals has rekindled Western interest in the technology. The European Space Agency (ESA) recently sponsored a project that produced an eLoran antenna suitable for mobile devices. Three transmitters are on-air in the U.S., presumably for testing, and the UK Ministry of Defence has issued a request for information, which is expected to lead to the purchase of a deployable eLoran system (the U.S. Air Force operated a deployable capability called Loran-D in the 1970s).
Originally developed and used in World War II, some still view Loran as old technology. Its advocates counter that today’s telephones and televisions are vastly improved over 1940s technology, and the same is true for eLoran over its older Loran-A and Loran-C versions.
A high-power terrestrial system operating at 100kHz, UK demonstrations with differential eLoran in 2014 showed an accuracy of 10 m positioning and 50 ns timing. The positioning accuracy for the previous version of Loran, Loran-C, was approximately 460 m absolute accuracy, 90 m repeatable accuracy and 5 µs.
Hellen Systems’ President, Bridge Littleton, says the partnership is “… excited to bring commercial eLoran to the UK as a unique resilient PNT capability” and cites its advantages as a secure signal able to penetrate deep indoors without the need for an external antenna. The UK frequency regulator, Ofcom, proposed offering commercial eLoran licenses in 2022 and began the process in 2023. Hellen was granted a UK spectrum license for eLoran earlier this year.
The announcement also lists Microchip, Chronos Technology, Ltd, Continental Electronics, and CGI as team members in the project.
The Dunhuang long-wave timing station, a critical component of China’s high-precision ground-based timing system, has been completed and tested. This marks a significant advancement in China’s development of a three-dimensional cross-timing system that spans air, space and land.
Zhang Shougang, director of the National Time Service Center of the Chinese Academy of Sciences, told Xinhua News that the high-precision ground-based timing system leverages eLoran radio long-wave and fiber-optic timing technology. This system is designed to operate independently of satellite navigation timing, providing backup, complementary functions and mutual enhancement with existing timing systems.
China has constructed three additional long-wave timing stations in Dunhuang, Korla and Nagqu. When combined with existing stations, the new stations are designed to achieve nationwide coverage of long-wave timing signals.
During the construction of the Dunhuang station, researchers reported significant breakthroughs in high-precision transmission control and pulse time reference feedback modulation technology. They achieved a megawatt-level Loran timing transmission accuracy of 20 ns, surpassing the current international standard of 50 ns.
This advanced timing system seeks to support economic and social operations, foster technological development and improve national security. Zhang Shougang noted that after nearly 60 years of development, China has built the world’s most technically complete national timing system.
The United Kingdom’s Ministry of Defence (MOD) is focusing its alternative positioning, navigation and timing (Alt PNT) project on deployable eLoran. This comes after industry days for Alt PNT in March and June 2024.
The announcement came in a Request for Information (RFI) on Sept. 20. It specifies that a contract will be let for the development of a deployable eLoran network. As part of that contract, the MOD also wants to develop:
A modelling capability, which will allow for theoretical analysis of capabilities and informing the concept of employment.
An assured capability within the Loran Data Channel
Information and demonstration of the resulting capability to stakeholders
UK PNT Policy Framework
Last year, the UK government announced a ten-point “policy framework” for advancing the nation’s PNT resilience. One of the ten points is:
“Develop a proposal for a resilient, terrestrial, and sovereign Enhanced Long-Range Navigation (eLORAN) system to provide backup position and navigation.”
Most have seen this as a provision for a fixed domestic system for use by critical infrastructure and applications. The UK already has an on-air single eLoran transmitter that provides a timing signal. An announcement about establishing two or more additional transmitters to provide PNT services for the British Isles and their adjacent waters has been anticipated.
The policy framework also includes:
“Develop a proposal for ‘MOD Time’ creating deeper resilience through a system of last resort and use NTC-provided timing to support MOD.” [NTC stands for National Timing Centre.]
It is not immediately clear how this RFI from the MOD fits these two provisions, if at all, or is entirely separate.
1970s Deployable Loran
Deployable Loran, or Loran-D was first developed for the U.S. Air Force in the 1970’s. An oral history recounts that a system was deployed early in the 70’s by the 6514th Test Squadron at the Utah Test and Training Range (UTTR), a component of Hill Air Force Base. It was built by Megapulse, employed a Hewlett Packard beam clock and 150 ft antennas, and was used for testing unmanned aircraft. There are also indications elsewhere that the Air Force used it for precision bombing.
Industry sources say that this earlier work provides a solid foundation for developing future deployable eLoran systems.
UK MOD Requirements
The RFI is fairly specific about the questions it wants answered. These requirements look nearly ready to be transformed into a Request for Proposal and contract language. They include:
The demonstrator system shall include a minimum of 3 transmitters to enable a suitable receiver to live demonstrate position and time determination from the system.
Across the coverage area, the system shall transmit a signal that allows receivers to achieve position and timing accuracy in line with the needs of defense platforms (which have not yet been specified).
The system shall be able to operate with and without GNSS access.
The system shall be able to operate both with and without access to eLoran signals from eLoran transmitters outside the deployable system’s group.
The system shall be capable of maintaining performance & accuracy for prolonged periods, including without access to eLoran and GNSS signals.
The system shall be able to be contained and transported in an ISO container.
The system shall be able to be assembled, initialized and disassembled by as small a team as possible.
Respondents must submit by the 18th of October to be considered.
An expert has warned the government of the United Kingdom that the lack of an alternative to Galileo threatens to put critical infrastructure at risk, according to a report in Daily Express.
Andy Proctor, formerly with the satellite and positioning, navigation and timing (PNT) cabinet office, submitted evidence of his concerns to the UK’s ministers.
“Our critical infrastructure is at risk from the loss of PNT, space-based or otherwise,” he wrote. “We are currently critically dependent upon GPS; the loss of which will have a major impact in capability and economically.”
Proctor is director of Rethink PNT, a consultancy firm.
He pointed out that the government disinvested in the eLoran terrestrial system that could have provided a backup, although this is slowly reversing.
“For 20 or so years there have been calls for action, yet the current status of inaction regarding the PNT strategy puts our systems at increasing risk, especially given the clear and present electronic-warfare systems being used in Europe today,” Proctor wrote.
Britain was removed from the Galileo project following Brexit, and has since been looking for an alternative PNT system.
the former Loran-C transmission antenna at Værlandet, Norway. (Photo: UrsaNav)
By Alan Grant and Dana Goward
In my “First Fix” editorial in the January 2022 issue of this magazine, I listed 10 questions about eLoran I had received from a PNT expert in response to an article about eLoran I wrote for the November 2022 issue. I encouraged eLoran proponents to address these questions. Two well-known authorities, neither of whom have a financial interest in the technology, stepped forward to help. Below, again, are my 10 questions about eLoran and their answers.
Alan Grant is head of Research and Development for the General Lighthouse Authorities of the United Kingdom and Ireland (GLA). He is an expert in radionavigation systems and leads the team that established the U.K.’s eLoran system, which operated from 2007 to December 31, 2015 in support of maritime users.
Dana A. Goward is president of the Resilient Navigation and Timing Foundation and a retired U.S. Coast Guard Captain. He also served in the federal Senior Executive Service as the maritime navigation authority for the United States. He has decades of experience with navigation policy and leading government policy and programs.
— Matteo Luccio, Editor-in-Chief
Accuracy specifics. While my November article stated that eLoran would have a two-dimensional accuracy of “better than 20 meters, and in many cases, better than 10 meters,” is that RMS, 95%, or some other statistic?
AG: Like any radionavigation system, the achievable accuracy will depend on several aspects, including the user’s location with respect to the broadcast stations and how error sources are modelled. The GLA eLoran service, when in operation in 2015, provided positional accuracy in the order of 8-10m (95%) to seven ports on the east coast of the UK. These ports had local reference stations to help manage temporal errors and the ports had been mapped to correct for additional secondary factors (ASF).i
DG: Others have reported greater accuracies using differential corrections.
Performance standard. GPS provides a commitment to users in a published performance standard. What specific measures of positioning accuracy, integrity and continuity would you recommend the proposed eLoran system be committed to provide (using the architecture described in the answer to Question 6)?
AG: The target performance would need to be tied to the target use cases to ensure the appropriate requirements are met. IALA provides guidance in this area for maritime services with general maritime requirements provided by the IMO within resolutions A.1046 and A.915.
Coverage. Would you recommend this eLoran positioning performance hold for the entire United States (including Alaska, Hawaii, Puerto Rico and other territories), only for the “lower 48” states, or only parts of these 48 states?
DG: The primary goal of any effort to complement and back up GPS/GNSS would be to make the nation and its citizens safer in at least two ways. First, to provide an alternative PNT source or sources in the event that signals from space were not available for any reason. Second to make GPS satellites and signals (and therefore the nation) safer by “taking the bullseye off GPS.” Having one or more alternatives will greatly reduce incentives for malicious disruption. To achieve these two goals the alternatives must be widely available and easily accessed. How widely available and easily accessed the United States or any other country wants to make such systems is a policy decision.
Current users. By number of users, the predominant common current civil uses of GNSS for positioning are consumer devices (mostly cellphones). By contribution to the U.S. economy, the predominant uses are high-precision applications. For what fraction of these uses would eLoran positioning be adequate? Could an eLoran receiver and antenna fit in today’s consumer devices?
DG: Lots of presumptions and assumptions in this question. Several overall thoughts, though. First, determining users’ real requirements can sometimes be difficult. I have a nice new full-size sedan. So, I think that is my requirement even though I could get to work almost as quickly and much less expensively if I owned a used compact car or caught the bus at the corner.
Second, GPS/GNSS will, hopefully, always be the primary source. The questions then are 1) how accurate can eLoran positioning become with additional work, and 2) how accurate does a fallback system need to be?
Durk van Willigen of Reelelektronika b.v. displays a combined GPS, GLONASS and eLoran receiver at the 2017 Munich Satellite Navigation Summit. (Photo: Reelelektronika)
Finally, as to equipment size, I recall seeing a photo of the first GPS receiver sitting on a pallet with two chairs for operators. Today, receivers are made at chip scale. Huge reductions in C-SWAP have been the growth arc for all kinds of technologies as they are implemented more and more widely.
In 2017 the Dutch company Reelektronika showcased a combination eLoran, Chayka, GNSS receiver that was only 6 cm long. This was achieved without a whole lot of investment in research and development. Who knows how low C-SWAP for eLoran receivers will go?
Future uses. Emerging civil uses of GPS for positioning include autonomous ground and air vehicles, navigation to space and in space, and lane-accurate car navigation. Which of these could be served by eLoran?
AG: The overall concept of having a mix of dissimilar position sources remains sensible for all modes. GNSS is expected to remain the primary means of position determination, with different use cases selecting different complementary systems based on their needs. eLoran may support some use cases but may not be the answer for all.
DG: Many believe GPS alone is not sufficient to serve some of the applications cited. This is the basis for language in both the European Radionavigation Plan and a U.S. Presidential Executive Order cautioning against over-reliance on GNSS. Perhaps GPS and eLoran together might be deemed sufficient. Or, perhaps a more diverse and resilient PNT architecture will give rise to additional applications such as precise positioning from 5G that will be sufficient.
Architecture. To maintain accuracy during a prolonged GPS outage, eLoran would require reference stations to calibrate time-varying propagation errors, as well as a certain number of transmitters for good nationwide geometry and for redundancy, ensuring service even if a transmitter is attacked or is taken off-line for maintenance. What architecture would you recommend to achieve this?
AG: The MarRINav projectconsidered a similar question for the UK and the project’s approach could be employed to consider this question for the United States.iv
DG: A good starting point for the United States might be the sites used by the shuttered Loran-C system. The federal government still retains custody of most of them. Also, considerable thought has been given to the questions of eLoran reference stations and integrity in the United States. PNT expert Mitch Narins, formerly of the FAA and now Strategic Synergies, advises that much of this work has been done. The FAA and Coast Guard conducted a study to deploy eLoran in the United States to support aviation non-precision approach, maritime harbor entrance and approach, and precise time and frequency users. The proposed architecture supported aviation’s demanding integrity requirement (1×10-7), maritime’s demanding accuracy requirement (8-20m), and time and frequency users’ precision requirements (100 ns/Stratum 1).
7. Infrastructure cost. What would be the cost of installing the required transmitters, power supplies, reference stations, communication links and control system for the architecture described in the answer to Question 6? Can you reference a recent and independent estimate? To a ballpark figure, what cost fixed-price contract would you accept to implement it? Similarly, what would be the annual costs for operating and maintaining this infrastructure?
AG: The MarRINav project produced a cost-benefit analysis report that addresses some of these questions, albeit aligned to the approach proposed for the UK. The documents are open source and available on the MarRINav website.
DG: To quote President Kennedy, “There are costs and risks to a program of action, but they are far less than the long-range risks and costs of comfortable inaction.”I agree with Dr. Grant that the capital costs in MarRINav are roughly transferrable to the United States. As another data point, the 2010 operating cost for Loran-C in the United States was about $36M/year. That number included several hundred employees, though. Plans to automate the system projected reducing annual costs to $15M/year in 2010 dollars.
Impact. eLoran transmitters are large and high-power. Providing positioning across the United States could require building some of them from scratch or significantly reconstructing old Loran sites. What issues — such as environmental, aviation safety and security — would this raise, and how would you recommend they be addressed?
DG: These issues would be dealt with the same way they are for any construction project. eLoran transmission sites are essentially the same as commercial AM radio stations. Reusing sites still owned by the government could make the process even easier. Compared to the cost and difficulty of putting PNT assets in orbit, these challenges should be relatively easy to overcome.
Receivers. Assuming all the above were achieved, it would accomplish nothing unless eLoran receivers were widely purchased, installed and used. How much would that cost? Who would pay? Should we assume that “if we build it, they will come”?
AG: This is a valid concern and has different answers depending on the planned use case and the level of national/international standardization required. Within the maritime sector, the IMO has approved a multi-system receiver performance standard that supports the use of all GNSS and terrestrial systems within one device, rather than having a separate eLoran receiver.
DG: I completely agree — adoption and use are absolutely key. Fortunately, government leaders have a wide variety of levers to influence adoption and use. These range from education and encouragement to regulation, legislation, and subsidies.
Alternatives. Given the widespread development of other positioning technologies over the past decade, much has changed since the earlier recommendations for eLoran. How do we know that eLoran is the right investment — or even a needed part of the solution or needed system in a system of systems — for the future of U.S. PNT?
AG: The MarRINav project researched and compiled details of different positioning, navigation and timing technologies supporting maritime navigation, within Deliverable D4. The recommended system-of-systems approach recognized that there was no one-fit-all solution, rather it sought to allow for a scalable solution that reflects users moving from location to location and between systems. It considered global, regional and local solutions, recognizing the cost vs. usable coverage tradeoff for each. The proposed solution of GNSS, supported by eLoran in combination with VDES R-Mode and radar absolute positioning, was deemed as the most appropriate mix for the UK, given geographical and political constraints. The approach can be ported to investigate the appropriate options for the United States.
DG: The U.S. Department of Transportation’s January 2021 report to Congress has findings similar to those in MarRINav. It described a system of systems that included fiber, satellites and terrestrial broadcast. The department subsequently said that a critical factor for a terrestrial broadcast system would be the coverage area per unit of required infrastructure. Of the systems discussed, eLoran met this criterion best. This recent finding is consistent with numerous other government reports, two previous government announcements that it would build eLoran, two recommendations from the President’s National Space-based Positioning, Navigation, and Timing Advisory Board and the technology’s on-going use around the world. Likely someday there will be something to replace GPS and other legacy technologies. We must work with the combination of technologies we have now until that day arrives.
Common Threats
Common threats to GNSS and eLoran could include the following:
1. Cyber attacks. Given that GPS’s OCX is said to be the most cybersecure system built by the U.S. Department of Defense, how would eLoran’s control system be even more cybersecure than OCX, to avoid a common cyber-vulnerability?
AG: Cybersecurity is a key concern and one that any navigation and safety of life system must consider. I will leave manufacturers of each system to comment on how secure they are. However, if we consider signal interference and data manipulation within this category, then using a stronger signal at a different frequency to GNSS provides some protection against jamming. While any radio signal can be jammed, the perpetrator would need more power and physically larger equipment to jam at lower frequencies.
DG: Yes, the security of control systems is very important and must be included in the design up front. Authentication and security of signals, and the cybersecurity of receivers must be as well. This is especially true for complementary systems for GPS since GPS signals are so open and vulnerable, and so many receivers are largely unprotected. We will have the opportunity to do better with a new system and avoid the huge expenses of OCX, the new GPS control system.
Additionally, let us not forget that cybersecurity is needed for much more than control systems. Signals and receivers need to be much more secure than civil GPS is right now. A new system, be it eLoran or another technology, will be able to build cybersecurity in from the beginning.
Physical attacks. Given concerns about possible physical attacks on GPS satellites, which move at multiple km/sec 20,000 km from Earth, would it not be easier to physically attack eLoran transmitters, which are stationary, terrestrial, in remote locations, and hundreds of feet tall and require massive power sources?
AG: We should not lose sight that any ground infrastructure can be attacked, regardless of whether it is a satellite uplink station or part of a terrestrial communications or positioning system. Careful selection of the transmitter location, along with suitable site security options should help deter the attack and mitigate the impact where possible.
DG: Every physical asset and every signal is vulnerable to some degree to attack by a host of malicious actors, and damage by a variety of natural occurrences. The key to resilience and making PNT sources less attractive targets is to have diverse sources with the smallest number of common failure modes.
Space weather. GPS is potentially vulnerable to severe space weather that could damage satellites or temporarily hinder signal propagation from space to Earth. However, severe space weather could also damage the power grid upon which megawatt eLoran transmitters rely. How would eLoran service be protected from the effects of severe space weather, such as a Carrington Event?
AG: Space weather has the potential to affect all radio broadcasts. Depending on the type of event it can affect performance several different ways, including ionospheric scintillation, applying forces to satellites or disrupting power networks. The aim is to use systems where the underlying failure modes are as different as possible. Using a combination of satellite and terrestrial signals, at different frequencies, with local power generation where possible can help mitigate the impact. Whether it’s possible to mitigate all the implications of a Carrington type event is not clear and perhaps one for the experts.
DG: With the available warnings about solar events, it is conceivable that both GNSS and terrestrial systems could be powered off or otherwise secured for such an event to minimize damage. A new-build terrestrial system could also be constructed with surviving a Carrington Event in mind. And, of course, terrestrial systems will be easier to access, repair, and replace than those in space. As for other possible issues with the power grid, generators, uninterruptable power supplies, and other backup methods can easily be installed. Before 2010, several U.S. Loran-C transmitters were in such remote locations, they never had grid power and were always powered by generators.
In January’s issue, he listed 10 questions from a PNT expert perhaps unfamiliar with eLoran.
These are important questions that must be asked of any technology, especially one under consideration to augment and back up our essential, but very weak and vulnerable, GNSS signals.
Yet the expert’s concerns pale in comparison to the essential questions about GNSS and PNT facing the United States and the West.
While I look forward to answers to the “10 questions” as a part of our ongoing professional dialogue, there are two important points of context we all need to keep in mind.
A Broad Consensus
First, Mr. Luccio’s assertion about eLoran being a part of the solution is more than reasonable. It also has a lot of impressive support from a wide variety of authoritative sources.
In 2008 and 2015, after much study each time, the U.S. government decided on and committed to building eLoran systems. Also, the U.S. government-sponsored National Space-based Positioning, Navigation and Timing (PNT) Advisory Board recommended eLoran in 2010 and 2018 as a part of securing the nation’s critical PNT capability.
In 2021, the U.S. Department of Transportation told Congress that wide-area terrestrial broadcast was a necessary part of a national PNT architecture. They later commented that infrastructure required per coverage area would be a key selection criterion for that broadcast technology. In other words, a system like eLoran.
Overseas, support for Mr. Luccio’s statement on eLoran is even stronger.
The United Kingdom has long endorsed eLoran and operates an eLoran transmitter as a timing reference.
Russia operates Chayka, a version of Loran.
Available information points to Iran’s terrestrial PNT system being a form of Loran or eLoran.
China and South Korea have long had Loran-C systems, and both are in the process of upgrading to the eLoran standard.
Each of these countries has publicly announced that it operates Loran/eLoran as a matter of national security in case space-based systems are jammed or destroyed, and to generally avoid overdependence on space-based PNT signals.
So, Mr. Luccio’s assertion was not at all revolutionary. Given all the studies, recommendations and existing uses, it would be surprising if he did not consider eLoran a part of the solution.
The Important Questions
Second, modern keying, encryption, authentication and other tech advances will help make all PNT technologies much safer and more resilient than they would have been decades ago, Loran and eLoran included.
Yet all will still have their strengths and weaknesses.
The most important questions we must ask are about how to establish the right level of national PNT security. These include:
What is the right combination of technologies and systems with different delivery and failure modes that complement and reinforce GNSS and each other?
How can the systems be efficiently and effectively implemented?
How can the services they provide be easily accessed and widely adopted to ensure all parts of society are protected?
Countries such as China have answered these questions and are well down the path to implementation and wide adoption. Their robust national PNT architectures support easier rollout of 5G, rural broadband and other systems. They also serve as solid tech infrastructure upon which to build myriads of technologies and applications yet to be conceived.
Those nations not so advanced must accelerate their efforts. Otherwise, they must resign themselves to perpetually coping with GNSS vulnerabilities, including the possibility of attacks, and an eventual second or third place in the world because of their shortsightedness.
