The Air Force Life Cycle Management Center’s Positioning, Navigation and Timing (PNT) Program Office, Integrated Solutions for Systems (IS4S) and AEVEX Aerospace have completed flight tests for the Resilient-Embedded GPS/INS (R-EGI) Modular Open Systems Architecture (MOSA). The tests demonstrated R-EGI’s ability to integrate third-party alternative PNT solutions to ensure reliable navigation in GPS-denied environments.
This achievement marks a step forward in developing R-EGI, demonstrating its ability to integrate a “plug & play” third-party alternative PNT capability that ensures reliable navigation in GPS-denied environments.
“This flight test represents a pivotal moment in the evolution of resilient PNT systems,” said Jeff Hebert, senior scientist for PNT at the Air Force. “The rapid and cost-effective integration of third-party PNT solutions into Department of Defense weapons systems is precisely why R-EGI and its open architecture were envisioned.”
The R-EGI system’s open MOSA design enables seamless integration of government and third-party applications to address emerging navigation threats. Its Mission Capability Navigation (MCNAV) component allows for seamless integration of external alternative PNT solutions under challenging conditions.
During six test flights on a Special Operations Command C-146A Cougar aircraft, R-EGI operated successfully in GPS-denied environments, validating the system’s resilience and capacity for real-time adaptability. Using AEVEX Aerospace’s LynxVBN vision-based navigation system, it maintained approximately 10 m of positioning accuracy for up to 2.5 hours. Notably, LynxVBN was integrated into R-EGI’s MCNAV software in just one hour, underscoring the system’s adaptability. As the algorithms continue to improve and evolve, R-EGI’s alternative PNT accuracy will only become more refined, enhancing its capability to perform in increasingly complex and challenging environments, according to the company.
“After demonstrating that the R-EGI architecture could integrate multiple GPS receiver vendors, and then three months later, witnessing its performance, from the Cougar-provided live-stream data feed, in real-time GPS-denied flight scenarios was the most impressive showcase we’ve seen in the program’s history,” said Major Bernard Mutz, project manager for R-EGI
The successful integration of alternative PNT technologies into R-EGI seeks to enhance the system’s GPS resilience. Also, it sets a new benchmark for reliable, flexible navigation in GPS-degraded environments, said Mikel Miller, senior vice president for PNT at IS4S.
In case you missed it, the European Union Agency for the Space Program (EUSPA) recently issued its first everUser Technology Report addressing both GNSS and Secure SATCOM. Though they seem to be different and distinct topics, EUSPA does a reasonable job of drawing them together with an “Editor’s Special — Synergies from Space” at the end of the document.
The first half of the report deals with GNSS and is an exploration and celebration of how far we have come with GNSS. While the report is aimed at “users” and is designed to be “technical,” it is written to be accessible by most who are generally familiar with the topic.
Also, a careful reading reveals several messages for policymakers.
Protecting Frequencies
The report opens with a celebration of what has now become a multi-constellation, multi-frequency, open positioning, navigation and timing (PNT) system with 110 satellites, two regional augmentation systems (Japan’s QZSS and India’s NavIC), and Satellite Based Augmentation Systems (SBAS). All of this depends, of course, on clear and uninterrupted signals.
One of the first cautions policy makers should note is a subheading in the section that reads “Frequencies: a scarce resource to be protected.” This is the first of many mentions of the need to protect signals and users from accidental and malicious interference.
From 2016 to 2019, the European Union’s STRIKE3 project deployed equipment to monitor L1/E1 signals in 23 countries across the globe. They found more than 450,000 signals that could interfere with GNSS, 59,000 of which were assessed to be intentional jamming or spoofing.
This was well before the current wars in Ukraine and the Middle East and before Russia’s malicious ongoing electronic warfare in the Baltic. So, even in the absence of aggressive nation-state actions, which could flare up at any time, STRIKE3 showed that GNSS interference was a significant problem threatening users’ reliance on GNSS.
Both the European Union and the United States have undertaken projects in response to widespread jamming and spoofing.
In Europe, EUSPA has begun the EGIPRON project, or European Global Interference PROtection Network. It aims to develop and deploy “…an interference monitoring system covering all European territories and worldwide areas of European interest” working with contractors Qascom and Leonardo.
The U.S. Department of Transportation (DOT) announced the “GNSS Situational Awareness Common Operational Picture GovCloud Environment” at the December 2024 National PNT Advisory Board meeting. The government version was described as operational, with a public version to be available in mid-2025.
These detection — and hopefully geolocation — systems will be great tools. Policy makers must remember, though, that better understanding the scope of the problem will not solve it.
Better laws and regulations to empower enforcement, along with improved enforcement capability, will both be needed if even a dent is to be made in the problem. Getting these in place will be significant legislative and budgetary challenges. Even then, the problem of accidental and malicious GNSS interference will not be solved. Authorities will just be able to manage it a bit better.
Toughen Receivers
A great majority of the GNSS portion of the document is appropriately devoted to receivers. They are, after all, the only part of the GNSS system over which users have any discretion and control.
Receiver design, signal processing, antennas and PNT processing are all discussed. The most attention is paid to describing the characteristics and appropriate uses of five different families of GNSS receivers:
Mass Market Entry-Level
Mass Market Premium
Professional Non-Regulated
Professional Regulated
Special Applications
Using the right kind of GNSS receiver for a given application is essential for safety and effectiveness.
The question for policymakers, though, is not whether the right technology exists to mitigate risks — it does. Rather, the issue is whether that technology is being used appropriately.
Most GNSS users are uninformed about GNSS issues and tend to purchase equipment based upon price rather than resilience. Policymakers must consider how to motivate users, especially in critical applications, to purchase and use more expensive equipment. Government leaders have many levers of influence at their disposal, from education to regulation and requirements. As of yet, however, we have seen few in use.
Alternative & Complementary PNT
The booklet devotes a page to “Complementary PNT Technologies” with the subhead “Complementary PNT technologies are redefining navigation solutions.” Saying “one size does not fit all” — which can also be said for GNSS — includes a graphic from the most recent European Radionavigation Plan of a conceptual, system of systems PNT architecture.
Perhaps more significantly, other pages have mentions of the desirability of “diversifying” PNT sources and “hybridizing” PNT sources.
Safety-Critical Applications
Overall, the GNSS section of the User Technical Report is an excellent general overview and reference document.
Its description of SBAS, however, might give a misimpression to the uninformed reader.
The title on page 12 reads “SBAS enhance GNSS performance and enable safety critical operations.”
SBAS improves GNSS accuracy with corrections and ionospheric models and helps with integrity. However, it does little to prevent service disruptions due to interference.
The title for SBAS conflict on page 12, with a comment on page 17, discusses “GNSS Vulnerabilities and Mitigation Measures.” The very last note on the page and in the tiniest type reads, “For critical applications, implement alternative (non-GNSS) technologies as a backup to ensure continuous PNT information.”
This latter statement is very much in keeping with the most current, 2023 version of the European Radionavigation Plan, which says:
“Thus, for critical applications or critical infrastructure protection, it is broadly accepted that GNSS, even in a multi-constellation and multi-frequency environment, should not be the unique source of PNT information. For those applications, an alternative PNT solution (back-up but also complementary) should be developed and maintained, not necessarily based on radio frequency technologies.”
To a certain extent, this has been echoed in the United States as well.
In 2020, a Presidential Executive Order warned against over-reliance on GPS/GNSS, saying the government “must ensure critical infrastructure can withstand disruption or manipulation of PNT services.”
Following this, in its January 2021 report on a PNT demonstration project, the DOT said:
“Promoting critical infrastructure owner/operator use of those technologies that show strong performance, operational diversity, operational readiness, and cost-effectiveness is worthwhile. Based on this demonstration, those technologies are LF and UHF terrestrial and L-band satellite broadcasts for PNT functions with supporting fiber optic time services to transmitters/control segments.”
Additionally, a 2023 presentation to an international group by the Office of the Assistant Secretary of the Air Force was titled “Alt. PNT — the Pathway to Resilience.”
GNSS are great systems, but we cannot let our understandable enthusiasm for what are truly miracles of technology unintentionally mislead others. Policymakers must be constantly on the lookout for such missteps and help us all maintain a broader, user-focused perspective.
Federal Communications Commission (FCC) Chair, Brendan Carr announced in a March 5 blog post that the commission would be addressing GPS alternatives along with Next Generation 911 issues at its next meeting.
Pledging that “…public safety and national security will be top priorities for us at the FCC” along with quick action on related issues, Chairman Carr said the commission’s March 2025 open meeting will start “… with an inquiry that explores alternatives to GPS.”
Describing GPS as indispensable but not infallible, Carr’s post showed a substantial appreciation of PNT and GPS alternative issues as well as much of the related policy history.
It also cites President Trump, Senator Cruz, and Senator Markey as advocating action to “… ensure we have a resilient system in place.”
In 2020, President Trump issued Executive Order 13905 on “Strengthening National Resilience Through Responsible Use of Positioning, Navigation, and Timing Services.” Designed to stimulate adoption of open market commercial solutions, it does not seem to have made the nation’s PNT substantially more resilient in the intervening five years. This may be because GPS is free and time and navigation have been provided by the government as free utilities for hundreds of years. Also, many GPS users may be unsure about the need for alternatives since the federal government has not yet acted to protect itself with an alternative system. Potential users are also reluctant to purchase commercial PNT services as they are unsure which commercial services will have the longevity to make the cost and effort of adoption and integration worthwhile.
President Trump also supported the need for GPS alternatives in Space Policy Directive 7, “The United States Space-Based Positioning, Navigation, and Timing Policy.” It called for the government to “…identify and implement, as appropriate, alternative sources of PNT for critical infrastructure, key resources, and mission-essential functions.” This directive was issued shortly before the end of the first Trump administration and, though the directive still stands, this provision has not yet been acted upon.
Carr’s mention of Senators Cruz and Markey undoubtedly refers to their joint sponsorship of the National Timing Resilience and Security Act of 2018. The act called for the Department of Transportation to ensure establishment of at least one terrestrial timing system as a backup for GPS signals. The first Trump administration and the Biden administration never requested funding for such an effort, so the mandate has yet to be implemented.
An FCC meeting on GPS alternatives is also timely as the commission has received two petitions related to provision of nation-wide PNT services. One is from NextNav, seeking spectrum to underwrite its proposal to work with telecom providers. The other is from the National Association of Broadcasters (NAB), asking to mandate and accelerate implementation of the new ATSC 3.0 television broadcast format. NAB says its Broadcast Positioning System signals will be included as part of that format.
While GPS alternatives will be discussed at the upcoming meeting, no decisions on systems is contemplated. Carr says the commission:
“… will vote on an inquiry to explore other Positioning, Navigation, and Timing (PNT) systems that can be complements or alternatives to GPS. Beyond answering technical questions, we hope this effort will engage stakeholders across government and industry to encourage the development of new PNT technologies and solutions.”
Discuss current PNT technologies and efforts, both from governmental and private sector entities, for developing complementary and resilient PNT technologies.
Seek comment on various space-based solutions for resiliency of PNT, such as medium Earth orbit (MEO) satellite systems and low Earth orbit (LEO) satellite systems.
Seek comment on various terrestrial solutions for resiliency of PNT, such as leveraging TV broadcast infrastructure, ground-based transmitters, and/or user equipment positioning.
For all technologies, ask commenters for information on the benefits and challenges of particular PNT technologies or solutions based on factors such as: geographic coverage; availability of existing equipment; use of spectrum resources; the extent to which the technology should be viewed as a complement to or substitute for GPS and other PNT technologies; performance characteristics such as range and precision; durability; international considerations; and the cost and incentives to develop, deploy, and maintain the technology or solution.
Seek comment on additional actions that the Commission could take to facilitate the security of PNT technologies available to consumers.
Seek comment on whether to amend the Commission’s existing rules or adopt new rules to promote adoption of complementary and alternative PNT technologies.
Ask questions about what role public-private partnerships, testbeds, or Innovation Zones may play to test and develop PNT technologies.
The FCC open meeting’s agenda also includes two items about 911 services. One of those is “Strengthening 911 Location Accuracy Rules” especially for the vertical (z) axis. This seems to be a separate and distinct issue from the PNT agenda item with the burden of performance and response placed on telecom providers. That said, some eventual linkage cannot be entirely discounted.
The meeting will take place on March 27 from 10:30 to 12:30 EDT. A formal agenda will be posted approximately a week in advance. The meeting can be live streamed at https://www.fcc.gov/March2025 and a recording will be available on YouTube shortly thereafter.
The U.S. Navy has selected Northrop Grumman to advance its airborne navigation capabilities by integrating Northrop Grumman’s LN-251M, the upgrade of the LN-251 inertial navigation system (INS)/GPS. This new system incorporates M-Code technology, which provides an encrypted, military-specific signal with improved resistance to jamming, offering better protection against potential threats.
According to the company, the LN-251M represents a significant advancement in naval aircraft navigation, being the first M-Code navigation system designed for this purpose. The M-code technology offers increased robustness against GPS signal degradation, which allows pilots to operate more effectively in areas where GPS signals may be compromised or unavailable.
The LN-251 series is designed to integrate seamlessly with existing aircraft navigation systems and is compatible with future software and GPS modernization upgrades.
NATO has selected SandboxAQ as one of approximately 70 companies to participate in the 2025 Defense Innovation Accelerator for the North Atlantic (DIANA) cohort. The selection process involved more than 2,600 submissions from 32 NATO countries. DIANA, established by NATO in 2023, aims to address complex societal challenges by bringing together innovative companies developing dual-use technologies for both commercial and defense applications.
SandboxAQ will join the cohort’s Sensing & Surveillance group, focusing on the development of its AQNav magnetic navigation system. AQNav is designed to provide a secure navigation alternative that does not rely on GNSS, making it resilient against jamming and spoofing. The system utilizes SandboxAQ’s proprietary Large Quantitative Models (LQMs), quantum sensors, and the Earth’s crustal magnetic field to offer an all-weather, day and night, terrain-agnostic navigation solution for military and commercial applications.
The AQNav system has undergone extensive testing, including more than 200 hours of flight tests with the U.S. Air Force, involving more than 40 sorties across various geographies and aircraft types1. In July 2024, AQNav demonstrated its capability to serve as a primary navigation source and showed potential for scalability across similar aircraft types without individual calibration.
As part of the DIANA program, SandboxAQ will receive resources, insights and developmental support to advance AQNav’s capabilities. The company will also have opportunities to test the system in specialized environments, leveraging DIANA’s network of experts in technology, commercial development and defense.
Iridium Communications is exploring the potential use of small satellites to demonstrate advanced positioning, navigation and timing (PNT) capabilities.
Iridium CEO Matt Desch discussed this initiative during the Smallsat Symposium in Silicon Valley, where he suggested the company might venture into the smallsat business, even if only for experimental purposes.
Desch said small satellites could also support the development of a very-high frequency (VHF) radio system aimed at enhancing pilot communications with Aireon, a provider of aircraft surveillance services using hosted payloads on Iridium’s satellites.
Iridium operates a constellation of 66 Iridium Next spacecraft in low-Earth orbit (LEO) for L-band connectivity services, along with additional spare satellites. Following an engineering assessment in 2024, the company expects this constellation to remain operational until at least 2035.
The Iridium Next satellites, weighing approximately 860 kg, are significantly larger than typical small satellites used for LEO communications, which generally range from a few dozen to a few hundred kilograms. While smaller satellites offer advantages in terms of faster and more cost-effective deployment for specific missions, Iridium’s larger satellites are designed for extended operational life, supporting its global, cross-linked network.
From Dec. 4-5, 2024, the National Space-Based Positioning, Navigation and Timing (PNT) Advisory Board met to discuss GPS-related topics. The PNT Advisory Board provides independent advice to the U.S. government on GPS-related policy, planning, program management and funding profiles in relation to the current state of national and international satellite navigation services. A March 28, 2024, GPS World article by Dana Goward highlighted that the PNT Advisory Board has been providing the government with independent expert advice about GPS and PNT for 20 years. He highlighted that the Board is chaired by retired Admiral Thad Allen and has six subcommittees.
This newsletter will highlight a topic that the emerging capabilities, applications and sectors subcommittee discussed at the final PNT Advisory Board meeting of 2024. The presentation title is “GPS High Accuracy and Robustness Service (HARS).” A white paper on the topic and the Dec. 4, 2024, presentation by Shachak Pe’eri, Ph.D., NOAA/NOS/National Geodetic Survey (NGS), can be found on the PNT Advisory Board website.
According to the document, the board prepared the white paper to support recommendation number PNT27-04-ECAS, which is to develop and implement a GPS HARS delivered to users via the Internet. The HARS concept was approved at the PNTAB-27 meeting (Nov. 16-17, 2022) and formally submitted to the National Space-Based PNT EXCOM co-chairs via Memorandum on Jan. 27, 2023.
Recommendation PNT27-04. (Photo: Presentation by John W. Betz, PhD Member, National Space‐Based PNT Advisory Board on May 29, 2024)
The November and December Advisory Board meetings are recorded, and individuals can listen to the entire meeting. The Board’s website provides links to the meeting agenda and presentations. Pe’eri’s presentation on HARS started at 10:30 am on Dec. 4 (2:04 on the recording).
During the meeting, the PNT Advisory Board officially stated that it supports the HARS Concept described by NOAA. Of course, the Board also stated that it has no money, but the Board’s stamp of approval of the concept is very important. Now, it is up to NOAA’s NGS to work with other federal agencies, such as NASA’s Jet Propulsion Laboratory (JPL), to work out the details and resources. By leveraging NASA’s real-time Global Differential GPS (GDGPS) System infrastructure and NOAA’s service delivery platforms, a high-accuracy, resilient service that ensures delivery of precise, reliable and secure GNSS corrections for a wide range of scientific and commercial applications can be built for the nation.
So, what exactly is the GPS High Accuracy and Robustness Service (HARS)? The following is a statement from a Jan. 27, 2023, PNT Memo:
“Implementing a GPS High Accuracy and Robustness Service: To augment GPS and overcome some inherent limitations of space-based PNT, the USG should provide a service comparable to the European Union’s Galileo HAS that provides signal corrections than enable better than one-meter level accuracy, as well as cryptographically-protected satellite navigation message data bits for integrity processing. The U.S. should develop and implement GPS HARS, based on the capabilities developed by the JPL for GDGPS, to be made available to users over the Internet.”
The white paper describes the problem and the solution as the following:
“The problem: GPS is falling behind other Global Navigation Satellite Systems (GNSSs) such as Europe’s Galileo and China’s Beidou. GPS has adopted an approach of allowing augmentation by third-party systems (such as Assisted-GNSS in mobile phones, WAAS for aviation accuracy and integrity, and commercial RTK for precision users), rather than providing specialized advanced services itself. Also, the data message modulated on the GPS signals is fragile. Environmental effects or malicious actions can prevent a receiver from reading the information or manipulate what is read, limiting the robustness of the GPS signals. Currently, GPS is the primary system in almost all GNSS chips, even chips made in Europe or Asia. That is: chips are designed to acquire GPS signals first, then signals from other systems. But Galileo and BeiDou are deploying high accuracy services that provide sub-meter position accuracy, enhancing satnav use in many civil applications. The absence of any plan for GPS to offer a similarly high accuracy service could cause GNSS chips to begin using Galileo or BeiDou, rather than GPS, as the primary system. A switch away from GPS as the primary PNT system is a problem for the US Government because it will lose its strategic advantage. Existing commercial chips are used in many strategically important US assets, such as airlines, ships, and organizations that support the US military. Once these chips change their architecture to Galileo-first or BeiDou-first, these strategic use cases depend on these services. It is one step in the direction of not having a GNSS system at all and borrowing the system of another power, exactly the situation that Europe and China were in before they built their own systems. GPS would no longer be the “pre-eminent space-based PNT service” called for in Space Policy Directive 7.”
“The Solution:A high accuracy and robustness service (HARS) provides information to user receivers, reducing errors and enhancing the ability to operate in challenging conditions. The PNT Advisory Board has identified a solution that the U.S. government can provide a HARS without adding cost and complexity to GPS itself; instead, the needed information from government or government-sponsored organizations can be obtained and provided over the Internet to properly equipped receivers. The result would be a world-class HARS at a small fraction of the cost or time, compared to implementing it on new GPS satellites. The HARS would provide cryptographically-protected robust (resistant to jamming and spoofing) GPS for critical infrastructure and would enable new applications (such as lane-dependent route guidance in automobile navigation and emergency vehicle guidance, GPS-only precision positioning of drones) that extend the societal benefits of GPS. HARS would be secure and less sensitive to radio noise and disruptions, including spoofing.”
The following are a few slides from Pe’eri’s presentation highlighting the need for HARS. He mentioned that there are six regional high accuracy systems and one global service that is already operational or in development.
Six regional HAS and one global HAS are operational or in development at this time. (Photo: NOAA/NGS)
NOAA’s presentation by Pe’eri was in response to a request by the Advisory Board. The Board was interested in learning more about the funding and operating a public service that can provide robust real-time GPS corrections. Summarized in three bullets:
High-Accuracy: Real-time corrections to GPS orbit parameters and clocks to enable more accurate positioning solutions.
Robustness: Nav Data (ephemeris) can be cryptographically signed and delivered on the same channel.
Service: Delivered over the Internet and is free to all users.
The HARS could be accomplished by employing the expertise, knowledge, and capabilities of NASA’s JPL and NOAA’s NGS.
NOAA has the authority to provide real-time operational services and regularly collaborates with other federal and state agencies and local communities. NGS manages and distributes the NOAA CORS Network (Foundation and Cooperative CORS). NASA JPL collects GNSS data and generates products with high accuracy.
NGS expertise and knowledge. (Photo: NGS/NOAA)
NASA’s GDGPS is a complete, highly accurate and extremely robust real-time GNSS monitoring and augmentation system. The CCDIS website states, “Employing a large ground network of real-time reference receivers, innovative network architecture, and real-time data processing software, the GDGPS System provides sub-decimeter (<10 cm) positioning accuracy and sub-nanosecond time transfer accuracy anywhere in the world, on the ground, in the air, and in space, independent of local infrastructure.”
JPL expertise and knowledge. (Photo: NASA)
By leveraging NASA’s real-time GDGPS System infrastructure and NOAA’s service delivery platforms, NGS and JPL can build a high-accuracy, resilient service that ensures delivery of precise, reliable and secure GNSS corrections for a wide range of scientific and commercial applications.
Pe’eri’s presentation highlighted HARS benefits to the daily operations of users of geospatial data.
HARS benefits for users. (Photo: NOAA/NGS)
The HARS concept is extremely important to the U.S. GPS user community, where the number of users is increasing every day. A 2019 Department of Commerce (NIST) study, “Economic Benefits of the Global Positioning System (GPS),” highlighted the economic damages a GPS outage would have on the agricultural industry.
The 2019 NIST study, “Economic Benefits of the Global Positioning System (GPS),” determined that $1.4 trillion in U.S. economic benefits from GPS. The study stated that a 30-day widespread outage could erode less than $1 billion in economic value per day. The study also highlighted the impact a GPS outage would have on Agriculture, stating that during planting season, economic damages in the agriculture sector could increase 30-day losses to $15 billion due to lower yields.
Table ES-1 and figure ES-1 from the 2019 report highlight the economic benefits of GPS for private sector use.
Table ES-1: Summary of economic benefits of GPS for private-sector use, 1984 to 2017. (Photo: NIST) Figure ES-1: Time series of GPS’s economic benefits for the private sector. (Photo: NIST)
I would encourage others to look at the PNT website, especially the Advisory Board website, to obtain information about space-based PNT. Other recommendations and letters from the Advisory Board to the Executive Committee (EXCOM) can be found on the PNT and Advisory Board websites. The webpage provides the Advisory Board’s recommendations on ways to improve GPS and national GPS management. The recommendations are published in the interest of public transparency.
The National Space-Based Positioning, Navigation, and Timing Advisory Board continued its discussions on how best to protect, toughen and augment GPS at its 31st meeting, which took place Dec. 4-5 at the Sonesta Redondo Beach and Marina in Redondo Beach, California. The meeting was convened by James J. Miller, of NASA, who is the board’s executive director, and chaired by retired Adm. Thad Allen of the U.S. Coast Guard.
On the first day, after hearing reports from its six subcommittees, the board heard the following presentations:
Karen Van Dyke, director, PNT & spectrum management, Department of Transportation (DOT), on DOT’s IDM and complementary PNT work.
Maj. Christine Bonniksen, retired from the U.S. Air Force, deputy director for flight projects, NASA Langley Research Center, and Shachak Pe’eri, Ph.D., acting director, National Geodetic Survey, National Ocean Service, National Oceanic and Atmospheric Administration (NOAA), on NOAA’s implementation of a GDGPS-based GPS High Accuracy and Robustness Service.
Anh Nguyen, Ph.D., NASA flight opportunities program (Bryce Space and Technology, LLC) and Lisa Valencia, NASA Space Communications and Navigation Program (Overlook Systems Technologies, Inc.) on the SpaceLoft 15 multi-GNSS flight experiment (see the article on p. 16).
Allison Kealy, Ph.D., director of the Innovative Planet Research Institute, Swinburne University, Australia, on resilient PNT.
Brad Parkinson, Ph.D., the board’s first vice chair, on a comparison of GPS with the other GNSS.
Satoshi Kogure, senior chief officer of satellite navigation technology, Japan Aerospace Exploration Agency on Japan’s Quasi-Zenith Satellite System (QZSS).
Moon Beom Heo, Ph.D., executive director of KPS R&D Directorate, Korea Aerospace Research Institute on the Korean Positioning System (KPS).
Matt Higgins, international engagement subcommittee chair on Galileo.
Cordell DeLaPena, executive officer, MilComm & PNT, Space Systems Command, USSF on the status of the GPS program, including L5, OCX, civil signal monitoring, resilient-GPS and low-Earth orbit PNT.
On the second day, the board held a roundtable discussion, then heard updates from its international members and representatives. For video of the proceedings, go to youtube.com/@nationalpntboardmeetings822/streams.
To celebrate Allen’s long service as this board’s chair, NASA conferred a beautiful plaque to him, bearing the following text:
“PRESENTED TO Admiral Thad Allen
With our deepest gratitude, the NASA community and our many partners are very thankful for the friendship and dedicated leadership you have provided as the Chair of the National Space-Based Positioning, Navigation, and Timing Advisory Board. Your advocacy on behalf of GPS users worldwide will always be remembered and cherished. December 2024
Kevin Coggins
Deputy Associate Administrator, Space Communications and Navigation
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION”
PNT services are integral to industries worldwide, from logistics and telecommunications to critical infrastructure. The rise of LEO satellites is set to revolutionize this space, overcoming limitations of traditional GNSS, such as vulnerability to interference and limited urban coverage, according to FrontierSI.
Key insights from the report, which is the first in a series of annual reports, include:
Industry impacts: How LEO PNT addresses GNSS vulnerabilities, offering more robust and accurate navigation solutions.
Government and regulatory challenges: The rise of commercial PNT players necessitates collaboration to address interoperability, spectrum management and governance issues.
Business innovation opportunities: Critical sectors such as logistics and autonomous systems stand to benefit from assured and precise PNT services.
Investment potential: The nascent stage of the LEO PNT market presents opportunities for investors to identify game-changing technologies and key players.
The report is recommended for professionals and organizations deeply engaged in satellite navigation, including:
Engineers, designers and project managers in the space and defense industries
Autonomous systems manufacturers
Policymakers and regulatory bodies responsible for satellite navigation and spectrum management
Commercial stakeholders in telecommunications, transport and logistics
Academics, researchers and analysts with an interest in satellite navigation technologies
Investors analyzing the growth potential of LEO PNT solutions
Providers of critical infrastructure reliant on precise timing synchronization
The LEO PNT State of the Market Report aims to provide stakeholders with the necessary insights to navigate this transformative period for PNT.
ANELLO Photonics has received a Phase I Small Business Innovation Research (SBIR) contract from the U.S. Navy. The six-month contract will allow ANELLO to demonstrate its optical gyroscope and sensor fusion technologies for navigation without relying on GPS.
Under the contract, the U.S. Navy will evaluate ANELLO’s integrated photonics technology and AI-based sensor fusion engine. These technologies aim to maintain accurate navigation in challenging environments where GPS signals may be unavailable or compromised.
ANELLO Photonics’ technology can be used for construction, agriculture, transportation, robotics, unmanned vehicles and national security. The company’s focus on navigation solutions for GPS-challenged scenarios aligns with growing needs in both military and civilian domains for reliable positioning systems in diverse environments.
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.”
The U.S. Space Force’s Space Systems Command (SSC) has awarded a $1.9 million contract to Slingshot Aerospace to enhance its GPS jamming and spoofing detection capabilities. This contract, Positioning, Navigation and Timing – Secure Electronic Navigation Threat Intelligence and Location (PNT-SENTINEL), aims to improve the company’s existing technology by incorporating advanced artificial intelligence and predictive analytics.
The PNT-SENTINEL program builds upon Slingshot’s previous work under the Data Exploitation and Enhanced Processing (DEEP) contract, awarded in October 2021. The technology developed through DEEP currently assists the U.S. Space Force in detecting GPS jamming and ground-based interference sources related to ongoing conflicts, potential future conflict zones and counterterrorism efforts.
GPS spoofing and jamming pose significant threats to both military operations and civilian infrastructure. Such interference can impact a wide range of operations, including satellite systems, ground and air operations and critical services such as commercial airline operations and vehicle navigation. The global reliance on GNSS has increased the importance of protecting these signals from interference.
Slingshot’s technology utilizes a mesh network of thousands of satellites to create a near-real-time picture of GPS jamming occurrences worldwide. This space-based approach offers a more comprehensive view of global jamming conditions compared to traditional ground-based detection systems.
As part of the contract, Slingshot will integrate its AI model, Agatha, into the PNT-SENTINEL system. This integration aims to enhance the technology’s ability to detect and differentiate between unintentional interference and deliberate jamming or spoofing attempts. The improved system will also implement pattern recognition algorithms to identify active jamming events and predict how situations may evolve.
The contract also includes provisions for expanding the system’s capabilities to monitor interference across multiple GNSS sources, not just GPS. This multi-GNSS processing will allow for a more complete, real-time view of jamming activities by incorporating data from allied nations’ spacecraft.
The PNT-SENTINEL system is designed to be interoperable with existing military systems, enabling near-real-time information dissemination to support rapid decision-making in national security operations. These enhancements aim to provide warfighters with a strategic advantage in GPS-contested environments.
