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.
Honeywell has unveiled its resilient embedded GPS/inertial navigation system (EGI), designed to address the evolving challenges of modern warfare and meet U.S. government mandates for greater power competition. This navigation system integrates GPS and inertial navigation technologies to deliver precise position, velocity and timing information for various applications.
Expanding on Honeywell’s H-764 and FALCN, the EGI is specifically designed to fulfill military needs in areas where GPS jamming and spoofing are prominent. The system includes M-code capability, an atomic clock and open architecture compliance, allowing crucial mission flexibility with alternative positioning, navigation and timing (PNT) forms.
It allows for the seamless integration of various alternative PNT sources, including vision navigation, celestial navigation and magnetic navigation for continuous and accurate navigation even in the face of GPS threats.
Honeywell plans to make engineering units of this EGI available in early 2026, with certifiable units following shortly after. The company said this timeline allows for thorough testing and refinement, ensuring the system meets the reliability and performance required for critical military applications.
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.
The European Union Agency for the Space Programme (EUSPA) has awarded a contract to a consortium led by GMV to design, develop and deploy the communications hub for the Governmental Satellite Communications (GOVSATCOM) programme. This contract, valued at up to €107 million ($119 million), is a critical component of the European Union (EU) satellite communications initiative.
GOVSATCOM is one of the five main components of the EU Space Programme, alongside Copernicus, Galileo, EGNOS and Space Situational Awareness. Its primary objective is to provide secure and cost-efficient satellite communication services to authorized governmental users in EU Member States.
The program aims to support various scenarios, including crisis management, border and maritime surveillance, critical infrastructure management and security operations in polar regions.
The communications hub is a critical element of the GOVSATCOM architecture. Its main functions include:
Ensuring optimal delivery of satellite communication services
Meeting the demand for operational services from EU Member State users
Planning for predefined medium-term communication needs
Handling dynamic and urgent requests from unforeseen scenarios
Operating under strict security and resilience requirements
The hub will manage satellite communication resources from EU Member States and services provided by the EU’s future multi-orbital secure communications constellation, IRIS2.
The consortium led by GMV includes Indra and Hisdesat. The contract was awarded following a competitive bidding process involving pre-selection consortia and execution of parallel contracts for preliminary design and capability demonstrations.
The increasing prevalence of GNSS spoofing in commercial aviation poses significant safety concerns and highlights the need for robust alternative positioning, navigation and timing (A-PNT) sources. This form of electronic warfare, which uses fake signals to confuse aircraft navigation and safety systems, has become a growing issue for civilian flights worldwide.
Pilots told The Wall Street Journal that spoofing incidents have risen in recent months. According to analyses from SkAI Data Services and the Zurich University of Applied Sciences, the number of affected flights per day increased from a few dozen in February to more than 1,100 in August 2024.
The issue of spoofing has expanded beyond active conflict zones near Ukraine and the Middle East, and now affects hundreds of civilian pilots daily on a global scale. The modern cockpit’s heavy reliance on GPS technology means that falsified data can have far-reaching consequences, breaching multiple aircraft systems and causing disruptions that may last anywhere from a few minutes to an entire flight.
According to anonymized reports shared with government agencies and industry groups, pilots have experienced many alarming incidents, including sudden clock resets, false terrain warnings and unexpected flight path deviations. This surge in GNSS spoofing attacks highlights the vulnerability of critical navigation systems and raises significant concerns about aviation safety in an increasingly complex environment.
All jammed up The Wall Street Journal reported that in August 2024, a United Airlines flight from New Delhi to the New York area encountered a GPS spoofing incident that affected its navigation systems for the duration of the flight.
Initially, the flight seemed to adhere to the standard GPS route across Asia, mirroring the path taken by previous flights heading to Newark Liberty International Airport. The spoofing attack, originating in the Black Sea region south of Ukraine, caused the aircraft’s GPS coordinates to deviate progressively from its actual position throughout the remainder of the flight.
Even after the plane had left the affected area, its reported GPS location continued to show erratic behavior, occasionally making sudden jumps. This suggested that the navigation equipment was struggling to recalibrate accurately. While alternative navigation systems ensured the flight’s safe completion of its intended route, the compromised GPS data indicated that it had terminated in the Atlantic Ocean. In reality, the aircraft landed safely at its scheduled destination in Newark.
Keeping operations safe Aviation safety officials said spoofing has disrupted some flights but has not posed major safety risks. Pilots are trained to use A-PNT systems as backups. However, managing false GNSS signals and alerts risks dividing the operator’s attention if a more severe problem arises.
“If we lose an airplane because of workload issues because of these problems we’re encountering, compounded with an emergency, that is going to be a horrendous event,” said Ken Alexander, the Federal Aviation Administration’s chief scientist for satellite navigation, during a pilot union forum in Washington, D.C.
Airlines are collaborating with aircraft manufacturers, parts suppliers, and aviation safety authorities to devise immediate solutions and long-term strategies. For example, the International Air Transport Association (IATA) and the European Union Aviation Safety Agency (EASA) are openly discussing these challenges and holding workshops to share best practices. Safety bulletins have also been issued for operations where spoofing and jamming are known to have occurred.
Industry insiders told The Wall Street Journal that the development of new equipment standards to enhance civilian aircraft resilience against spoofing attacks is not expected to be finalized until 2025.
Navigating issues across sectors According to anonymized reports collected by OpsGroup, an aviation safety organization that includes pilots, dispatchers and other airline staff, various attacks have caused navigation issues across multiple sectors.
GNSS spoofing has disrupted operations in Europe but has not endangered flights, said Florian Guillermet, executive director of the European Union Aviation Safety Agency. Pilots had to divert to airports they did not intend to land at, and earlier this year, an airline temporarily halted operations at an Estonian airport that was not equipped with ground-based navigation as a backup for GNSS.
Boeing said manufacturers, carriers and regulators globally are contributing GPS expertise for solutions to ensure safety. Boeing and Airbus are working with airlines to help develop procedures to assist pilots, the companies said.
United and American said their pilots are equipped with several ways to navigate with precision, even with GPS interference. American said it has not experienced disruptions or significant safety concerns from GPS interference.
Insights from industry experts
During the 64th Civil GPS Service Interface Committee Meeting — hosted at ION GNSS+ 2024 from Sept. 16-17 — The presentation “Complementing GNSS for Resilient Performance Based Navigation” by Okuary Osechas Ph.D., and Gary A. McGraw, Ph.D., addressed the critical role of complementary positioning, navigation and timing (CPNT) technologies in aviation, particularly in light of increasing threats to GNSS.
The presentation highlights the impact of radio frequency interference (RFI) on aviation, including jamming and spoofing. These pose significant risks to aviation safety by reducing operational margins. The prevalence of these threats is increasing, necessitating alternative navigation solutions.
Performance-based navigation (PBN) is essential for modern aviation, enhancing efficiency and flexibility. However, it relies heavily on GNSS, making it vulnerable to disruptions, again highlighting the need for CPNT services.
Integrating CPNT sources ensures resilient navigation capabilities. This includes leveraging legacy navigation aids and modernized terrestrial systems. Various complementary technologies such as eDME, eLORAN, LDACS-NAV and LEO SATNAV are being assessed for their operational effectiveness, compatibility and potential to support aviation needs.
The researchers recommend the following to address these challenges:
Near-term solutions: Implementing eDME for backward compatibility. Medium-term strategies: Utilizing eLORAN for wide-area time distribution. Long-term goals: Developing LDACS-NAV to enhance spectrum efficiency and standardization. Collaborative efforts: The presentation calls for international cooperation in research and development to advance standards and infrastructure investments in complementary PNT technologies.
Mitch Narins’ answer to the question, “If not GNSS, then what?” in the August 2024 issue’s EAB Q&A column, conveys an important message. As a result of their quality and availability, services offered by GNSS create dependencies and subsequently the expectation that of course they must always be there. However, recent experiences have shown we cannot rely on that expectation because either natural or hostile occurrences can disrupt GNSS services, no matter what measures are taken to protect them. That is why the U.S. Department of Defense (DOD), in its “Strategy for the DOD PNT Enterprise,” assessed that, “To combat man-made and natural threats to GPS, other sources of PNT information will be necessary to assure continuous PNT service …”
The strategy describes a layered PNT architecture using global (GPS), regional (eLoran), and local (or self-contained) sources of PNT information. It states, “The global PNT layer is space-based and available worldwide. The regional PNT layer may be implemented in areas … where PNT resiliency must be assured with backup capability. The local layer provides PNT information using man-made and natural information sources available for a limited time or over a limited area.” To achieve resilience from this layered architecture, the strategy provides an integration concept in which GPS and other GNSS are individually integrated with PNT information from the other layers into resilient applications to operate through the hostile environments they will encounter.
Unfortunately, the U.S. government is ignoring a major piece of this layered strategy in favor of space-based and local or self-contained solutions, as it has dismantled virtually the entire legacy Loran infrastructure in the United States and completely in Alaska, although GPS backups are lacking in the Arctic and northern Pacific regions. The loss of the Alaska sites is particularly concerning as the Arctic and northern Pacific Ocean coverage they would provide is a valuable backup to vulnerable GPS signals at a time when other nations are eying the sea lanes north of Alaska/Canada and conducting excursions around the Aleutian Island chain and the Alaskan coast. Coincidentally, the DOD has just published a new “Arctic Strategy,” which requires availability of PNT from GPS (at least) for its success, though “PNT” is not mentioned. However, without effective PNT, whether from GPS or other sources, the systems on which the strategy depends will fail.
As Mitch notes, there are those GNSS advocates who see strengthened GPS/GNSS as the best answer – but real-world events highlight the need for diversification, and now other nations are expanding their Loran-based regional systems. For its Arctic interests and domestic critical infrastructure as well, the U.S. must wake up to reality and do the same.
OneWeb Technologies has launched Astra, which is designed to maintain low-Earth orbit (LEO) SATCOM connectivity in GNSS-compromised environments.
The package includes a software-defined outdoor receiver that leverages assured positioning, navigation and timing (A-PNT) broadcast services, significantly enhancing connectivity resilience. Astra can process PNT signals from GNSS and alternative sources across multiple frequency bands to offer continuous connectivity and situational awareness, even in challenging spectrum-contested environments.
The system is compatible with non-GNSS A-PNT broadcast services, such as Iridium. It can identify the optimal PNT source while producing an output signal compatible with the standard GPS L1 interface. In addition to its commercial applications, Astra aligns with the military’s Primary, Alternate, Contingency, Emergency (PACE) communications plan.
Locus Lock has partnered with Xona Space Systems to develop a GNSS receiver that uses Xona’s multi-frequency PULSAR service. Locus Lock aims to provide a robust software-defined GNSS receiver for commercial and military applications.
According to the company, Xona’s PULSAR service will be delivered via a constellation of low-Earth orbit (LEO) satellites, which orbit the Earth approximately 20 times closer than traditional GNSS satellites. This proximity allows PULSAR to offer higher signal power and a modernized signal design to offer improved multipath mitigation, higher accuracy and increased protection against radio frequency interference and spoofing compared to current GNSS systems.
The technology is suitable for various applications, including vehicles navigating dense urban areas, agriculture and construction, UAVs, high-speed aircraft and defense applications. Locus Lock’s GNSS software stack can be deployed on existing customer computational infrastructure, ranging from small embedded devices to larger centralized computers. This flexibility allows for adaptation and configuration of the software to suit specific deployed environments.
The system features inertially aided carrier-phase differential GNSS (CDGNSS) for maintaining precision in challenging ecosystems, advanced interference mitigation and detection technology to ensure authentic GNSS signals are received, and the dual-antenna, triple-frequency RadioLion RF front-end for capturing raw GNSS signals. These features offer signal situational awareness, anti-spoofing, and interference mitigation.
UAVOS has collaborated with a client to conduct extensive testing of UAVOS’ autopilot system, which utilizes computer vision technology. UAVOS’ engineering service supported this testing with its advanced avionics system integrated into its unmanned helicopter.
The UAVOS autopilot system uses computer vision and artificial intelligence (AI) to navigate the UAV in GNSS-denied environments with precision and reliability.
The system’s onboard computer vision-based alternative navigation module, powered by deep learning algorithms, provides the UAVOS avionics system with accurate geospatial coordinates. This innovative approach allows for seamless navigation in both daylight and nighttime conditions, ensuring safe take-off and landing procedures without relying on external GNSS signals. By enabling the drone to effectively “see” and interpret its surroundings, UAVOS has created a solution that grants UAVs unprecedented autonomy and operational flexibility.
TrustPoint has secured two Direct-to-Phase II contracts from SpaceWERX, totaling $3.8 million, to advance its GPS-independent ground control segment and develop an advanced positioning, navigation, and timing (PNT) security application. The application is designed to address critical challenges within the Department of the Air Force (DAF) and strengthen the United States’ national defense.
The Air Force Research Laboratory (AFRL) and SpaceWERX, the innovation arm of the U.S. Space Force and a division within AFWERX, have partnered to streamline the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) processes. Their efforts focus on accelerating proposal-to-award timelines, expanding opportunities for small businesses and reducing bureaucratic overhead through continuous process improvements.
In 2018, the DAF introduced the Open Topic SBIR/STTR program to broaden its funds’ range of innovations. This initiative has paved the way for companies like TrustPoint to develop innovative capabilities contributing to national defense.
TrustPoint is developing a commercial GPS service using a C-Band low-earth orbit (LEO) satellite constellation. The system is designed to offer the high performance, security and availability required for autonomous navigation, critical infrastructure and national security.
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.
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.
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.
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.
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.
SandboxAQ has been awarded an SBIR Phase 2B Tactical Funding Increase (TACFI) by the United States Air Force (USAF) to further develop its dual-use AQNav magnetic navigation (MagNav) system. Under the contract, SandboxAQ and its partner AFWERX will explore new configurations of the AQNav technology, including a pod-based attachment, for use on a broader range of aircraft platforms, such as unmanned aerial systems.
AQNav navigation technology combines proprietary artificial intelligence (AI) Large Quantitative Models (LQMs), powerful quantum sensors and the Earth’s crustal magnetic field, resulting in a solution that operates effectively in all weather conditions, day or night and across any terrain. AQNav technology is completely passive and operates in real-time, offering an unjammable and un-spoofable alternative to traditional navigation methods. This system functions entirely independently of GNSS, offering a secure and dependable navigation option in environments where satellite signals may be compromised or unavailable. This is a key example of applying quantitative AI – AI models trained on quantitative data and not language. SandboxAQ is a leader in Large Quantitative Models (LQMs), in this case to pull the signal from the background magnetic noise for navigation.
This funding increase extends a prior Direct-to-Phase-II SBIR contract awarded to SandboxAQ in January 2023. To date, SandboxAQ’s AQNav technology has logged more than 200 flight hours and more than 40 sorties across multiple regions on four different aircraft types, ranging in size from single-engine planes to large military transport aircraft. In this process, AQNav was successfully tested in two USAF exercises – Exercise Golden Phoenix and Exercise Mobility Guardian – Air Mobility Command’s largest exercise at the time.
AQNav uses a powerful quantum magnetometer system to acquire data from Earth’s crustal magnetic field, which exhibits geographically unique patterns – similar to a human fingerprint. AQNav uses proprietary LQMs to compare this data against known magnetic maps, enabling the system to quickly and accurately find its position. Due to the high sensitivity of foundational quantum sensors, AI algorithms are applied to improve the signal-to-noise ratio, removing any mechanical, electrical, or other interference that would impact the system’s ability to acquire its location.
AQNav is available worldwide and can be used in air, land, and sea applications. The system does not rely on visual ground features or satellite transmissions to function and is not affected by weather conditions. Additionally, AQNav’s passive technology emits no electronic signals, which reduces the aircraft’s detectability. It operates at room temperature, requires no shielding, and has a small form factor that can be integrated into a wide variety of platforms, from multi-engine airliners to unmanned aerial vehicles.
SandboxAQ is developing AQNav as a dual-use solution to address the need for resilience to GPS vulnerabilities, which extends societally and economically. In addition to the USAF, SandboxAQ is engaged with several aerospace leaders to test and develop AQNav, including other allied governments, Boeing and Acubed — Airbus’s Silicon Valley research and innovation center.
