The top screen showing the hydrogen maser and cesium clocks in an adjacent isolated room used for realization of the timescale for research purposes. Students presenting their work to the USNO and Microchip Inc., visitors. (Photo: University of Alabama, Tuscaloosa)

The University of Alabama, with the support of the National Science Foundation (NSF), has established a program unlike any other in the country. It focuses on positioning, navigation, timing, and frequency (PNTF) as its own discipline, with a special emphasis on precise timing.

The Alabama Collaborative for Contemporary Education in Precision Timing (ACCEPT) is an NSF Research Traineeship (NRT) program designed to train the next generation of graduate (master’s and Ph.D.) degree holders in PNTF.

ACCEPT provides interdisciplinary training and education for physics, engineering, mathematics and computer science majors. The school hopes to make it a graduate program eventually. Enrollees are awarded a fellowship that includes a $34,000/yr stipend.

“The ACCEPT program was created because industry and government officials told us they could never find enough people in this field,” said Adam Hauser, the program’s executive director, who is also an associate professor of physics and astronomy at the university. According to Hauser “It is the only program in the nation directly addressing a larger scale workforce development in precision timing.”

Left to right: Dr. LeClair, Dr. Hauser and Dr. Bandi founded and run the ACCEPT PNT program at University of Alabama. (Photo: University of Alabama, Tuscaloosa)

ACCEPT’s Technical Director — also billed as “Time Lord” — is Thejesh Bandi, an associate professor. He reinforces Hauser’s message about the scarcity of focused talent in the area. “This field is greying,” he says. “We need young minds who will also bring in fresh ideas.”

Hauser describes the program as “a flexible multidisciplinary course curricula that includes professional development, and real-world training with our industry and government partners.”

The program’s “interdisciplinary” nature is reflected in the ACCEPT team. In addition to physics and astronomy, faculty from mathematics, electrical and computer, civil, aerospace, and mechanical engineering, as well as the communications and higher education departments, are included.

This diversity of expertise is needed for ACCEPT’s ‘holistic education” approach founded on four pillars.

1. Industry-Directed Curriculum: First, because the goal is to supply qualified graduates to fill critical national needs in industry, the foundational curriculum is based on and will continue to evolve with input from commercial entities in the PNTF space. In addition to several government agencies and labs, the ACCEPT Advisory Board includes representatives from SpectraDynamics, Aerospace Corporation, Raytheon Technologies, Microchip Technologies, L3Harris Technologies, OEWaves, Inc, Safran S.A., Northrop Grumman Corporation and the Resilient Navigation and Timing (RNT) Foundation.
2. Sustained Industry & Community Immersion: The program’s major focus is moving beyond academia. Internships and PNTF professional community events are mandatory. Students attend the National Institute of Standards and Technology (NIST) Time and Frequency Division’s time and frequency seminar each year. In their second year, they begin attending the Institute of Navigation’s annual Precise Time and Time Interval (PTTI) meeting. As their research and professional skills mature, they are expected to progress from attendees to poster presenters and speakers.
3. Professional Development: Reinforcing preparation for moving beyond the classroom, ACCEPT trains students to “… effectively work across academic, policy, governmental and industry sectors,” according to Hauser. “They need to be able to advocate as a professional to a larger audience effectively.” This means including students in programs like the university’s Speaking Studio and Capstone Center for Student Success. Communication skills, teamwork and ethics are particular focus areas.
4. Research: Bandi’s Research Quantime Lab is hosted by Professor Patrick LeClair’s Department of Physics and Astronomy. “Research projects for ACCEPT fellows and trainees are designed in conjunction with our government and industrial partners and focus on cutting-edge innovations that solve today’s problems in currently used technologies,” Le Clair said.

The lab strongly focuses on Quantum Engineering research, though there are also opportunities in Characterization and Calibration, Networking and Synchronization, and research into Precision Devices.

Click here for more information about applying for an ACCEPT fellowship or becoming an industry partner.

<p>The post ACCEPT: University of Alabama prepping next generation of PNTF experts first appeared on GPS World.</p>

According to ESA’s website, key findings in the paper include:

• Increasing Dependence on PNT Services – particularly for consumer and autonomous solutions. Accurate timing remains a critical use case, especially in telecom and power distribution.
• Geopolitical and Technological Challenges: Rising cyber-attacks, jamming and spoofing, advancements in AI, ML and quantum computing will have significant impacts. Anticipate new regulations.
• Technological Trends Driving PNT Demand: The proliferation of connected devices (IoT), autonomous driving, advanced air mobility, smart grids and autonomous vehicles will drive the demand for resilient and robust PNT.
• System Architecture Evolution: Future PNT systems will utilize a combination of data sources, including multiple GNSS constellations, cellular networks (5G/6G), terrestrial systems, augmentation systems, and autonomous sensors. This “system of systems” approach will enhance performance and ensure independence from single points of failure.
• Emerging Technologies and Sensor Integration: Advances in space segment technologies, receiver designs and sensor integration, new signal designs, flexible payloads, advanced clocks, inter-satellite links, and higher power amplifiers are highlighted.

Luis Mayo

We spoke with Luis Mayo, NAVAC’s chair, to get his take on this seminal work.

Question: To set the stage, what is NAVAC?

Luis Mayo: NAVAC is a group of external PNT experts that ESA has assembled to provide independent advice on navigation issues, and especially for NAVISP.

Q: Where can NAVAC’s formal recommendations be found?

Mayo: We perform an assessment of the NAVISP status every two years. We provide our recommendations as a conclusion of this assessment. Beyond that, our formal recommendations are collected in documents like this white paper or in proposals for modifications or adjustments to the work plans of the programs.

Q: How does ESA leadership generally view and react to NAVAC conclusions and recommendations? Does it act upon every recommendation?

Mayo: They are generally receptive. However, we are just an advisory body, so it is up to them to take on our recommendations. They often do so and use our advice to add weight to their proposal to the Navigation Programme Board, but they do not necessarily have to.

Q: PNT Vision 2035 is a substantial document. Clearly it involved some time and effort. Why was it written? Is it something ESA requested?

Mayo: The paper was the initiative of NAVAC members to inform the ESA Ministerial Conference in 2025. These conferences take place every three years to define the roadmap for the next period. New European space programmes, extensions or redirections of existing ones, and budgets are approved at these meetings.

Q: We thought we might make a modest contribution to the definition of the future ESA navigation programmes. What, if anything, did NAVAC find surprising or unexpected about findings included in the Vision?

Mayo: I would say that we hardly found anything too unexpected or surprising. The findings are the conclusion of multiple discussions on the subject over the past few years. We have just expressed them in a more articulated way.

If anything, and from my personal perspective, I would like to highlight that this exercise helped me realize that the deployment of some of the most exciting or expected applications of PNT technologies — such as autonomous driving — depend on the development and deployment of multiple other technologies that might not be necessarily available in the mid-term.

AVAC’s first meeting in 2018. From left to right: Javier Benedicto, ESA Navigation Director, and NAVAC members Alessandra Fiumara, Peter Grognard, Giorgio Solari, Rafael Lucas Rodriguez, Pierluigi Mancini, Roger McKinlay, Stefano Debei, Nityaporn Sirikan, Bernd Eissfeller and Luis Mayo. (Photo: ESA)

Q: What are the three most important things policymakers should understand from the document?

Mayo: First is that many infrastructures or services critical to the daily lives of the citizens are dependent on PNT technology.

Second, they cannot take for granted that GPS or Galileo services will be always available, not to mention GLONASS or BeiDou. Satellite navigation systems are vulnerable and are continuously under threat. Enabling assured PNT service is a must.

And third, there is more to PNT than satellite navigation. Other complementary or alternative technologies should not be abandoned. In fact, some of those technologies might even change the way in which we have traditionally conceived satellite-based navigation.

Q: What are the most important things policymakers should do to enable the PNT needed by 2035?

Mayo: I think they have to sustain the existing satellite-based navigation systems and foster the development of new technologies and systems that improve the robustness of the services. We have done a lot so far to provide PNT services globally. When you come to think of that, it’s really wonderful what we have achieved this far. We cannot afford to lose what we have, but that has proven not to be enough. Therefore, policymakers should keep helping the development of new technologies and services that complement what we have, improve the quality of the services and ensure its continuous availability and integrity.

They should also look beyond the current service volume. Spacefaring nations should be aware of the fact that they will need this kind of technology to support future missions. Deploying systems able to provide PNT services beyond the coverage of the current GNSS is an absolute necessity to support such missions.

Q: The vision says the EU must consider no longer having access to GLONASS and BeiDou. There are a number of threats that are common to all GNSS. Why not consider loss of access to all either temporarily or permanently?

Mayo: We have not considered a completely catastrophic situation such as losing access to all GNSS in our vision. We understand that GPS, Galileo and eventually other constellations or augmentation systems will remain available and provide at least partial coverage for PNT services.

Q: The vision makes recommendations about mitigating interference, using AI and extending the GNSS service volume. What else should policy and technology decision-makers take from the document and act upon?

Mayo: We must not forget there is a clear case for investing in future PNT systems. ESA should keep up to pace with foreign competitors that seem ready to increase their expenditure in these types of problems.

They also have to be conscious that satellite-based navigation is not enough. We have to look for alternative and complementary systems to reach the level of confidence that we need on PNT solutions.

Q: Perhaps you are thinking of all the PNT systems China has deployed?

Mayo: I am really thinking about what we are not doing in Europe or in the United States. We need to build alternatives that might not have global coverage but would allow us to maintain essential PNT services running at home.

Q: Resilience seems to be an important theme in the document, but it was not the subject of a specific recommendation. Could you speak to that?

Mayo: Resilience is a pervasive theme throughout the whole document. This is a major concern. We have to find a way to build a system of systems that can deliver to the user a trustworthy PNT solution at any time.

Resilience is, today, a key consideration in PNT, and we cannot do anything but acknowledge this fact. We might not have insisted enough on the importance of this feature for future PNT systems, but policymakers must undertake any actions required to improve the resilience of the existing PNT systems and services, probably by promoting the development of alternative independent PNT systems.

Q: What else should GPS World readers know about the Vision?

Mayo: Read the document. It is not that long. Also, think that it has been written from an independent and experienced standpoint. We at NAVAC do not pretend to hold the full truth, but I believe that we have a quite comprehensive view of the matter and that this would be useful for the reader.

<p>The post PNT Vision 2035 – A must read first appeared on GPS World.</p>

The warning came in a four-page memo to the Deputy Secretaries of Defense and Transportation from retired Admiral Thad Allen, Chair of the advisory board. The memo was nominally a report of the board’s April 2024 meeting in Colorado Springs.

The overwhelming majority of Allen’s message, though, dealt with GPS and U.S. PNT being vulnerable, the importance of PNT to the nation’s safety and security and the failure of the government to do the things it said it should and would do. It says:

“America’s continued over-reliance on GPS for PNT makes critical infrastructure and applications vulnerable to a variety of well-documented accidental, natural and malicious threats.

…our conclusion is that PNT, in general, and GPS, in particular, have not been accorded their rightful prominence in the national policy agenda.

Simply put, the Board believes that the 20-year-old framework for GPS governance and the current policy statements establish neither the priority that the system deserves nor sufficiently clear accountability for its performance.”

The reason for this was assessed to be that the leadership and governance structure established by 2004’s NSPD-39 and confirmed in 2021’s SPD-7 was not working.

Allen gave a recent policy document on critical infrastructure as an example. All critical infrastructure sectors use PNT, and most depend on it.

“These findings were reinforced just earlier this year by the release of the National Security Memorandum on Critical Infrastructure Security and Resilience (NSM-22, April 30, 2024). We were surprised to discover that GPS is nowhere mentioned in that important document.”

While not mentioned in the memo, PNT was also not mentioned in national cybersecurity documents issued last year. This is despite timing being essential to the operation of IT systems, and time and location data being key elements in many applications.

Allen’s memo also emphasized that the real issue is not about GPS, but overall national PNT capability. He went so far as to say, “Space Policy Directive 7 (SPD-7), U.S. Space-based PNT Policy, must be revisited and the term ‘space-based’ should be removed from its title” (emphasis added).

Reinforcing this message, the following table comparing U.S. and Chinese national PNT systems was included in the memo.

“The Board believes it is time to take a fresh look at our approach to PNT governance and establish a clear strategy for re-establishing an unquestioned position of leadership for the United States. To be successful, such a strategy requires a governance structure characterized by clearer authority and accountability. Ideally, the administration should propose legislation to Congress that would support this goal with a clear mandate (authorization) and resources (appropriations) adequate to the task.”

As part of his report of the April meeting, Allen’s memo reaffirmed the board’s nine recommendations from January of last year and added three more:

• Direct the U.S. Space Force to establish a way for “good enough” monitoring of GPS L5 signals using existing capabilities and set L5 signals healthy subject to a “use at your own risk” caveat, just as is done with L2C today. We recommend establishing a deadline of September 2024.
• Direct federal Chief Information Officers to acquire and install multifrequency dual-system (GPS-Galileo) receivers to complement GPS use. The Department of Transportation and the Department of Homeland Security should actively encourage critical infrastructure users to adopt multifrequency dual-system (GPS-Galileo) receivers.
• Assign a lead agency and single individual with clear responsibility and authority for the end-to-end prompt detection, characterization, and removal of significant sources of interference to GNSS in the United States.

Allen’s memo comes on the heels of a similar warning to United States leaders about the nation’s vulnerability to GPS disruptions. On July 18, the

National Security Space Association published a report titled “America’s Asymmetric Vulnerability to Navigation Warfare: Leadership and Strategic Direction Needed to Mitigate Significant Threats,” which cited several national PNT shortfalls from the Federal Radionavigation Plan as significant concerns.

Two of that paper’s key findings are:

“Long-standing lack of progress on issues important to U.S. national, homeland, and economic security,” and

“Focused leadership, properly empowered and resourced, is essential to the national PNT strategy’s success.”

It warned that significant disruption to GPS “…could have cascading effects which unravel America’s socioeconomic fabric…”

<p>The post Experts to PNT leaders: “It’s not working!” first appeared on GPS World.</p>

Photo: tifonimages / iStock / Getty Images Plus / Getty Images

Describing a dangerous “asymmetric vulnerability to navigation warfare” a recent paper from the National Security Space Association (NSSA) calls for a wide variety of actions to mitigate the threat. The most important, “Focused leadership, properly empowered and resourced…”

The nineteen-page paper, in some ways, reads like a primer on GPS and positioning, navigation and timing (PNT), providing background and context for policymakers unfamiliar with the technology and the United States’ broad dependence upon it.

“Long-standing lack of progress on issues important to U.S. national, homeland, and economic security.”

The lack of focused leadership, according to the paper, is evidenced by long-standing failures to follow through on a variety of mandates from senior leadership over the course of the last 20 years. Quoting from the Federal Radio Navigation Plan, it cites persistent shortfalls in national capability as including:

• Assured, real-time PNT in physically impeded environments (e.g., indoors, urban canyons, underground facilities).
• Sufficient accuracy and integrity in electromagnetically impeded environments — including operations during spoofing, jamming, and natural and unintentional interference.
• Higher accuracy with high integrity; timely notification/alarming when PNT performance is degraded or misleading, especially for safety-of-life applications or to avoid collateral damage.
• Ensuring PNT services, including supporting information technology (IT) infrastructure and supply chain are protected from cyber threats
• Ability to accurately locate sources of intentional and unintentional interference in a timely manner.
• Insufficient resilience and survivability when GPS services are unavailable or untrusted.

“American society has been transformed by the availability of GPS.”

The paper describes four decades of GPS being incorporated into virtually every technology and used by every critical infrastructure. It calls the harm to society should it be lost “incalculable.” It also notes that the operation of many space systems that support critical infrastructure and/or critical national applications is itself dependent upon GPS for proper operation.

The military utility and advantages brought by GPS are also discussed. These include:

• Its role as the lynchpin for precision strike.
• Enabling “… the maneuver, synchronization, and massing of effects from dispersed forces.”
• PNT to achieve information and decision superiority over an adversary.

“Merely the threat of disrupting GPS services might be enough to impact U.S. national security and foreign policy.”

The paper says recent actions by and ongoing threats from adversaries of the United States are a critical concern.

Electronic warfare (EW) and cyber attacks by Russia, China, Iran, and North Korea demonstrate the ease and effectiveness of such vectors, as well as the seriousness of the threat.

As one example, Russia’s impending launch of a nuclear-armed anti-satellite weapon has the potential to both destroy or damage GPS satellites nearby and interfere with radio communications. NSSA recently published a paper on the Russian nuclear ASAT threat.

A potentially even more serious threat would be if Russia should deploy a nuclear-powered directed energy or electronic warfare weapon. Such a device would be “reusable” and could threaten an even larger number of space platforms or, in the case of an EW device, both space-based and terrestrial receivers.

“GPS blackmail”

The paper posits that the United States’ overdependence on GPS is so great that it could be subject to “GPS blackmail.” It suggests that this may already have occurred.

Prior to Russia’s invasion of Ukraine, it destroyed a defunct satellite with a ground-based missile, creating thousands of pieces of debris. Shortly thereafter, state-sponsored TV announced that Russia would destroy all 32 GPS satellites if NATO “crossed its red line.” Despite 90,000 Russian troops massing along the border, “U.S. officials decided against sending certain military equipment to Ukraine to avoid provoking Russia.”

“…could have cascading effects which unravel America’s socioeconomic fabric…”

NSSA warns that U.S. “critical infrastructures, national essential functions, and military forces could be at grave risk.” Among the impacts of a major GPS disruption, it counts:

• Loss of U.S. political prestige and influence.
• Degradation of the informational element of national power (IT and telecommunications).
• Severe socioeconomic implications. “given the integration of GPS into critical infrastructures and their interdependencies, lengthy disruption just of the power grid, for example, could have cascading effects which [would] unravel America’s socioeconomic fabric…”
• Harm to national and homeland defense. Leadership is needed to perform national essential functions.

While the paper makes several specific recommendations for actions by various departments, it also identifies national-level leadership as key:

“The United States must rapidly develop and implement a comprehensive, whole of nation, strategy to redress its asymmetric vulnerability to Navwar and restore U.S. leadership in space-based and terrestrial PNT. … Focused leadership, properly empowered and resourced, is essential to the national PNT strategy’s success.”

The NSSA paper “America’s Asymmetric Vulnerability to Navigation Warfare: Leadership and Strategic Direction Needed to Mitigate Significant Threats” was sponsored by the Resilient Navigation and Timing Foundation and can be accessed here.

<p>The post US dangerously behind, PNT leadership needed first appeared on GPS World.</p>

Two months later, Vladimir Putin began regularly jamming and spoofing GPS for aircraft and ships across a broad swath of the Baltic and northern Europe. It was the world’s first instance of such extensive activity in the absence of armed combat.

Properly executed, Britain’s policy framework will position it as a global leader in sovereign and resilient PNT. It will also provide ample new business opportunities for British businesses to fill this growing need.

Photo: franckreporter / iStock / Getty Images Plus / Getty Images

Awareness and Planning

The product of years of effort under both Coalition and Conservative governments, the PNT policy framework addresses challenges that have been extensively documented and studied.

The nation’s over-reliance on space- based PNT has long been recognized. Its National Risk Register listed solar activity as a threat to PNT in 2012. When, despite extensive lobbying by the UK, the rest of Europe shut down its Loran transmitters in 2015 to prevent competition with Galileo, Britain kept its single transmitter on air as a national precise time reference. In 2018 a “Blackett Report” documented the nation’s over-dependence, estimated the consequences of service outages and made a series of recommendations. A 2021 economic report further estimated the scale of the problem.

All this well before Russia’s demonstrations of the fragility of GNSS with its attacks on Ukraine and recent aggression in the Baltic.

Yet action on Britain’s way forward was repeatedly deferred.

The sticking point seems to have been deciding upon the mechanics of how the government would deal with the invisible PNT utility, which is a capability essential to every government department and every sector of the economy and society. Should it be in the Department for Transport? Perhaps in Business and Trade or Defence? Some suggested the Cabinet Office should lead addressing the PNT challenge.

The final decision was a cross- government office hosted by the Department for Science, Innovation and Technology. The office includes members from the Ministry of Defence and is tasked with leading and coordinating a whole-of-government approach.

Moving Forward

It is easy to be skeptical about the success of this new enterprise. Regardless of the nation, government policy frameworks, strategies and the like often can be a way for politicians and bureaucrats to create the impression of action without having to ever really do anything. Documents are often published and then go on a shelf, never to be seen again.

That does not seem to be the case here, though.

The very first action item in the PNT policy framework is to “[e]stablish a National PNT Office …to improve resilience and drive growth with responsibility for PNT policy, coordination, and delivery.”

While several of the 10 items begin with “develop a proposal for…,” the projects are both considered and specific, such as a timing system “of last resort” for the Ministry of Defence and the expansion of eLoran.

Britain’s integrated governance and system-of-systems approach to PNT can make the nation virtually immune to the kinds of disruptions and infrastructure challenges being seen in the Baltic and conflict zones around the world.

Achieving that goal will involve the development of new user equipment, systems to prioritize and integrate different PNT sources, new interfaces for various infrastructures, improvements to existing technologies (e.g., an encrypted component for eLoran to make it even more secure and reliable), and new policies for responsible PNT use in critical applications.

When complete, the UK will have the sovereign and resilient PNT it needs to support national, homeland and economic security.

Global Leadership and Profit

Yet Great Britain is not the only nation over-dependent on fragile PNT signals from space provided by others. Most of the world is in the same situation.

By actively promoting and sharing its developing expertise and tech stack, the UK will become a global thought leader and technology provider for sovereign and resilient PNT. A capability that will be in greater and greater demand as malicious actors, both large and small, continue to exploit the weaknesses of satellite-based navigation and timing.

Yet, to realize these benefits, the UK must act swiftly and seize the moment.
At present there is a leadership vacuum in this field. While China has its own extremely robust and integrated PNT system based on a combination of clocks, fiber, terrestrial broadcast eLoran, and space, it does not seem eager to export that to others. China may prefer to woo nations into dependence on its BeiDou satellite PNT system, rather than enabling others’ sovereignty.

Additionally, while entrepreneurial South Korea has implemented its own space-based, eLoran and fiber PNT, it is unclear how integrated the various sources are. We have also seen no evidence that they have plans to share, or sell, their success to others.

As disruptions to GPS and other GNSS continue to increase around the globe, so, too, do calls for and moves toward solutions that include alternatives.

Last year the European Union issued a tender for an integrated GNSS/eLoran receiver. Türkiye has implemented its own local terrestrial PNT systems in several port and urban areas. India envisions expanding its regional navigation satellite system to cover the globe.

Britain has the plans, capability, and resources to become the world leader in this essential and growing technology sector — and the government is working with the Royal Institute of Navigation and other learned bodies to make it a reality.
Yet its window of opportunity may already be closing.

Rather than regarding its PNT policy framework as a routine item of work, we hope the UK government seizes this opportunity for international leadership and reaps all the inherent diplomatic, security and economic benefits.

<p>The post UK’s PNT foresight could presage world leadership and profits first appeared on GPS World.</p>

Photo: Jetlinerimages / E+ / Getty Images

In a recently released paper, the respected analytics firm London Economics determined that the presence of backup systems at the Denver and Dallas Fort Worth airports prevented any noticeable impacts on air travel despite each having experienced a disruption of GPS signals for 24 hours or more. By contrast, recent GPS interference at an airport without a backup system caused scheduled air service to be canceled until an alternative to GPS was established.

Also important to the lack of impact at Denver and Dallas was that the signals interfering with GPS, with a few minor exceptions, only impacted aircraft in the air.

GPS is essential for the safe and efficient movement of aircraft and support vehicles on the ground at airports, as well as the transport of crews, passengers, supplies, and cargo to and from airports, communication systems, and numerous other services.

Backups needed for both air and ground

Previous work by London Economics has shown that disruption of GPS for these ground functions would likely cause numerous flight delays and cancellations. Delays in the arrival of flight crews, passengers and supplies, for example, would quickly upset flight schedules. If this happened at a major airport, such as Denver or Dallas Fort Worth, disruptions could ripple through the entire air transport system. Wide-spread delays, cancellations and schedule adjustments would bog down air travel across the nation, if not the world.

The incident in Denver was caused by an accidental transmission from a government installation on Jan. 21. 2022. It impacted aircraft within approximately 50 nautical miles of the airport and lasted 33 hours before the source was identified and turned off.

The Dallas incident began on Oct. 17, 2022, and affected aircraft within about 110 nautical miles. It continued for 24 hours before ending on its own. The source has never been identified.

Reducing aviation backups may be a bad idea

In addition to recognizing the value of terrestrial navigation systems for aviation, the London Economics paper cautions about moves in the United States and Europe to “rationalize” these systems by reducing their number. In the event of longer or widespread GPS disruptions, the impact of an insufficient number of terrestrial systems could be significant. The cancellation of air service to an airport in Estonia because of chronic GPS jamming is used in the paper as a cautionary tale.

Instead of reducing the number of old backup systems, London Economics suggests policymakers consider establishing more widely available sources of terrestrial PNT. Taking a fresh look might identify alternative PNT sources for aviation that could also be used by other critical infrastructures. Perhaps even in consumer applications as well.

U.S. government representatives were approached for consultation and comment for this paper and expressed their willingness to participate. Unfortunately, they were unable to obtain permission to do so.

London Economics’ work on this effort was commissioned by the Resilient Navigation and Timing Foundation.

The paper “Aviation GPS Incidents Show Importance of Backup Systems. Policy Makers Take Note.” can be accessed from the foundation’s online library here.

<p>The post Study: GPS disruptions in aviation show importance of backups first appeared on GPS World.</p>

Aircraft operating near Seoul, South Korea spoofed to points in the ocean 28 to 30 May 2024. (Image: SkAI Data Services)

On the morning of May 30, 2024, Benoit Figuet posted on X that 40 aircraft operating into and out of South Korea had been spoofed over the previous 18 hours.

According to a press release by South Korea’s Ministry of Science and Information and Communication Technology (MSIT), by May 31 at 17:00 (KST), 201 airplanes and 731 ships had experienced GPS problems.

Professor Jiwon Seo at South Korea’s Yonsei University reports that the interference has, as of June 3, entered its fifth consecutive day.

Benoit Figuet is the co-founder of SkAI Data Services in Zurich, Switzerland. In collaboration with the Zurich University of Applied Sciences, SkAI created the world’s first public Live GPS Spoofing Tracker website. The site uses ADS-B data to detect and display in near-real time, aircraft being spoofed around the world.

South Korean military authorities have identified North Korea as the source of interference.

While the spoofing exhibits many of the same traits as interference in the Black Sea and elsewhere, Figuet has noted some differences. “We even see aircraft impacted at low altitudes,” he said. “We have observed this happening below 5,000 feet and even affecting an aircraft taxiing on the ground at the airport. The source must be at a reasonably high elevation or fairly close by.”

North Korea has a history of engaging in hybrid, non-kinetic warfare by interfering with GPS in the South, though this is the first large-scale event since one lasting from March 31 through April 5, 2016.

During the 2016 event, five different locations along the border of South Korea were identified as sources of interference. One is at an elevation of approximately 740 m and only 30 km from Inchon International Airport.

Another unique feature of the ongoing interference, according to Figuet, is the dynamic nature of the spoofed location. Unlike previously observed “circle spoofing,” the reported locations generally appear as tracing a figure eight pattern in the ocean near a point where the territorial seas of both countries meet.

Some of the spoofed locations have also been observed drifting over the North Korean border.

Local media have reported that the interference seems to be in conjunction with maritime maneuvers being conducted by the South Korean Navy and police vessels. The North has complained about intrusions into its territorial sea during these operations, a claim disputed by South Korea.

To help counter the effects of the North’s interference, South Korea has added to and upgraded its eLoran system. It has also included the eLoran upgrade in a comprehensive resilient PNT architecture that includes television signals and plans for a regional positioning, navigation and timing (PNT) satellite system.

According to Pyo-Woong Son, Ph.D., “South Korea is set to enhance its navigation and service reliability with the fully operational and established eLoran system. This system is expected to ensure that ships can navigate safely even during large-scale GPS signal disruptions, like those the country has recently experienced.” Son is a Senior Researcher at the Korea Research Institute of Ships and Ocean Engineering.

“In addition to maritime applications, eLoran will significantly contribute to the reliable operation of autonomous vehicles, such as urban air mobility (UAM), which are rapidly gaining popularity as future modes of transportation.”

“Furthermore, eLoran will play a crucial role in enhancing the reliability of public and private sector services, including broadcasting, telecommunications, and finance, where precise timing synchronization is essential,” according to Son.

Loran-C was used in many aircraft for decades before the advent of GPS. While eLoran signals are available across most of the Far East, receivers are not included in the navigation suites of commercial aircraft.

Aircraft operating into and out of Incheon International Airport have, so far, been able to use local terrestrial aviation-specific navigation aids to safely approach, land and depart.

Mr. Dana A. Goward is President of the Resilient Navigation and Timing Foundation and is a frequent contributor to GPS World.

<p>The post North Korea spoofing aircraft and ships first appeared on GPS World.</p>

It also happened in San Diego at the premier event for UAV operators— the XPOTENTIAL 2024 conference of the Association for Uncrewed Vehicle Systems International (AUVSI).

AUVSI is the world’s largest nonprofit organization dedicated to the advancement of uncrewed systems and robotics. Members present included corporations and professionals from more than 60 countries involved in industry, government and academia and work in the defense, civil and commercial markets.

One of NavtechGPS’ directional finder identifies the source of interference at AUVSI’s Xpotential 2024 in San Diego. (Image: Dana Goward)

Among conference attendees were Franck and Trevor Boynton of NavtechGPS, a small Northern Virginia company specializing in GPS products and related services. One of their services is locating devices that are interfering with GPS reception.

“In our work around the country we have found a wide variety of devices interfering with GPS,” said Franck Boynton. “It’s a lot more common than you think. We found truckers with jammers interfering with port operations, for example,” he said. “But accidental interference is an even bigger problem. Most of the time we find it is just some malfunctioning equipment making the radio noise.”

Boynton’s experience is consistent with the 2019 European Union STIKE3 sampling project that detected more than 450,000 signals with the potential to interfere with GPS and other satnav signals. Experts determined that only about 10% of those were intentional. The rest seemed to be a byproduct of mechanical and electrical equipment not functioning quite properly.

Of course, intentional or accidental, interference with GPS signals can be a problem for both manned and unmanned aircraft, vessels and vehicles.

Intentional interference in conflict areas has turned UAVs and missiles away from their targets, and in some cases, back on attackers. It has impacted the safety and efficiency of aviation and maritime traffic nearby. As one example, regular jamming in the Baltic region recently resulted in the cancellation of scheduled commercial air service to a city in Estonia.

Accidental interference has caused survey UAVs to crash and created multi-day problems at the Denver and Dallas-Fort Worth major airports.

In at least one instance accidental interference almost ended in tragedy. In 2019 a commercial passenger aircraft near Sun Valley, Idaho nearly crashed into a mountain. Fortunately, a sharp-eyed radar controller hundreds of miles away intervened and directed the aircraft back on course.

Nearly 600 vendors filled the AUVSI XPOTENTIAL exhibit hall this year. While perusing the displays, the Boyntons detected a strong signal interfering with GPS frequencies. Thinking it was coming from one of the exhibits, they were surprised to find that not only did it turn off and on but it seemed to be moving around.

Using one of the direction finders that NavtechGPS sells, they were able to track the source to a film crew roaming the hall and speaking with exhibitors and attendees. The wireless microphone being used for interviews turned out to be the culprit. Since the film crew was unable to repair or replace the mic, the interference continued intermittently inside the hall for the rest of the event.

“Interference of all kinds with GPS and other satnav signals is a growing problem,” according to Franck Boynton. “As we continue to implement more autonomous systems, it will be increasingly important to ensure they have resilient navigation, and we eliminate as many sources of interference as possible.”

AUVSI did not respond to requests for comment for this story.

<p>The post GPS jamming at UAV expo first appeared on GPS World.</p>