Category: GNSS

2024 recap: Trends, obstacles and opportunities in the GNSS/PNT industry

In 2024, we witnessed emerging trends, challenges and opportunities that significantly impacted the GNSS/PNT industry, ranging from advancements in surveying technology to ways to combat the increasing threats of jamming and spoofing. In this year in review, we highlight notable stories from 2024.

To read more, visit our full digital edition archive.

January

Image: Advanced Navigation

Charting uncharted waters: Bathymetry in action

This article discussed advancements in bathymetric surveying techniques, highlighting three projects — from SBG Systems, CHC Navigation (CHCNAV) and Advanced Navigation — that are charting underwater environments. It showcased the exploration of the Great Blue Hole in Belize using submarine-mounted sonar, creating a digital twin flood model for China’s Yellow River using unmanned surface vehicles (USVs) and UAVs and the development of an autonomous vessel for surveying wet gaps in military operations.

February

Aligning the trades: GNSS for architecture, engineering and construction

Surveying is an ongoing process on construction sites. Surveyors are the first on the site before any other work begins and the last ones there to map the project “as built.” Total stations with GNSS receivers, tablets and other mobile digital devices are their essential tools, increasingly complemented by UAVs and lidar scanners. In this story on architecture, engineering and construction (AEC), we highlighted three building projects — from ComNav Technology, CHCNAV and Eos Positioning Systems — as well as photos from Juniper Systems.

Photo: Safran Federal Systems

March

2024 GPS World simulator buyers guide

In our 13th annual Simulator Buyers Guide, we featured simulator tools, devices and software from nine prominent companies that aid GNSS receiver manufacturers in product design.

April

L5-first for improved resilience in mass market GNSS

Paul McBurney, co-founder and CEO of oneNav, emphasized the advantages of L5-first GNSS receivers in enhancing resilience against GNSS interference and jamming in mass market applications. He shared how traditional receivers prioritize L1 signals, limiting their effectiveness in high-interference environments, while L5 signals, which have a higher chipping rate and power, can improve jamming resistance by up to 15 dB. The article advocated for the development of L5-first systems to boost GNSS resilience, particularly for critical infrastructure, although challenges such as acquisition complexity and cost must be addressed before widespread adoption.

May

(Photo: CAST Navigation)

Combating jamming and spoofing: PNT on the battlefield

Jamming and spoofing continue to be the key challenges to military use of GNSS. While the production and adoption of M-Code receivers is delayed, defense contractors are developing several approaches to identify, locate and neutralize these threats — including CRPA antennas, embedded GPS inertial (EGI) navigators, software-defined radios and cryptography. In this cover story, executives from seven companies presented their perspectives on the GNSS/PNT challenges faced by U.S. and allied military forces, their market niche in this area and their latest products.

June

NextNav petitions FCC for new spectrum band

NextNav’s petition to the FCC seeks to reconfigure the 902-928 MHz band for a new terrestrial positioning, navigation and timing (TPNT) service. This service aims to complement GPS, enhancing location reliability in urban areas. The integration with 5G technology could further improve positioning services. However, the petition has raised significant concerns within the GNSS industry. Industry leaders argue that granting NextNav access to this spectrum could disrupt existing technologies that rely on the same band. The proposed higher power levels could lead to interference, jeopardizing the operational reliability of various sectors, including supply chains and healthcare. The Federal Communications Commission (FCC) has received more than 1,700 comments highlighting concerns about harmful interference and calling for careful evaluation before any regulatory changes are made. The outcome of this petition could significantly influence the future landscape of positioning technologies in the United States, affecting both GNSS capabilities and the viability of critical applications that depend on current spectrum usage.

July

PNT without GNSS

For the fourth year in a row, the topic for our July cover story was complementary positioning, navigation and timing (PNT). The ongoing challenges of combating jamming and spoofing, as well as enhancing resilience in PNT systems, have been prominent themes in our articles and industry throughout 2024. The U.S. National Space-Based Positioning, Navigation and Timing Advisory Board has been actively working on strategies to “protect, toughen and augment” GPS. The term “augment” refers to enhancements made to GPS and the integration of complementary PNT sources that can partially or fully replace GPS. For this cover story, Editor-in-Chief Matteo Luccio interviewed executives from four companies that design, produce and operate various complementary PNT technologies, highlighting their diverse approaches to this challenge.

Genesis satellite.

August

Innovation: ESA’s Multi-Modal space mission to improve geodetic applications

The European Space Agency (ESA) has established the Genesis mission, a groundbreaking space project that will collocate four space-based geodetic techniques — GNSS, VLBI, SLR and DORIS — on a single satellite for the first time. This mission aims to improve the accuracy and stability of the International Terrestrial Reference Frame (ITRF) to 1 millimeter with long-term stability of 0.1 mm per year, which is crucial for detecting small variations in Earth’s solid, fluid and gaseous components. The Genesis satellite, set to launch in 2028, will orbit at an altitude of about 6,000 km with an inclination of 95° and will operate for at least two years. Members of the Genesis mission team shared how it has the potential to significantly impact various GNSS and Earth observation applications by improving geodetic and geophysical observations, as well as enhancing precise navigation and positioning capabilities.

(Photo courtesy of ION)

September

ION GNSS+ 2024

ION GNSS+ 2024, held Sept. 16-20 at the Hilton Baltimore Inner Harbor, showcased more than 400 technical presentations spanning six sectors. GPS World had the opportunity to engage in a series of discussions and panels, including a plenary session with a presentation on a space project and one on circumnavigating the globe in a sailboat using only paper charts, a compass and a sextant to navigate.

INTERGEO 2024

The GPS World team touched down in Stuttgart, Germany, for INTERGEO 2024, held from Sept. 24-26. This year’s expo and conference showcased solutions to address critical global issues such as GNSS jamming and spoofing. GPS World Publisher Brian Kanaba and Account Manager Tim Carolin made their debut at the show, joining show veteran Editor-in-Chief Matteo Luccio. The show attracted more than 17,000 visitors from 121 countries and featured 579 exhibitors.

October

Lidar helps unlock secrets in Amelia Earhart mystery

The October edition of “Mapping Marvel” focused on research conducted for The Discovery Channel’s documentary, “Finding Amelia.” This film explores the latest expedition aimed at uncovering the mysterious fate of Amelia Earhart. It featured contributions from SPH Engineering and investigated the theory that Earhart and her navigator, Fred Noonan, may have crashed in Papua New Guinea during their 1937 attempt to circumnavigate the globe.

The team utilized lidar technology to conduct low-altitude flights that produced detailed maps of the ground beneath the dense jungle. This approach revealed potential hidden features, including Japanese troop trails and a structure resembling Earhart’s Lockheed Electra.

November

Richard Langley

The last one: A look back at 35 years of ‘Innovation’

The November 2024 issue of GPS World featured Professor Richard Langley’s 300th and final “Innovation” column. His first one appeared in the January/February 1990 issue, the magazine’s very first. In celebration of Richard’s decades-long contribution to GPS / GNSS / PNT, we published a selection of testimonials and photos from some of his colleagues and friends, gathered by his former students Sunil Bisnath and Attila Komjathy.

December

Directions 2024: GNSS constellation updates

This year’s “Directions” feature offers updates on all four GNSS constellations and a regional one. Representatives from each program — BeiDou, GPS, Galileo, GLONASS and QZSS — reflect on the year’s developments, sharing how PNT technologies aim to enhance both defense and civilian applications, ultimately improving navigation capabilities worldwide. The feature highlights significant milestones, including the modernization efforts within each constellation.

December 10, 2024
Raytheon receives Space Force GPS OCX contract extension

The U.S. Space Force’s Space Systems Command (SSC) has awarded Raytheon a $196.7 million contract extension for the GPS Next Generation Operational Control System (OCX) program — despite being years behind schedule. This latest award brings the total OCX contract value to nearly $4.5 billion since its inception in 2010. However, according to the U.S. Government Accountability Office (GAO), the total amount is approaching $8 billion.

The OCX program, designed to enhance GPS infrastructure, has faced significant setbacks. It is currently about seven years behind the original schedule, with the GAO reporting that the system of 17 ground stations was not ready by its October 2024 deadline. Further testing is required for the system to be operational by December 2025.

Despite these challenges, OCX remains critical for modernizing GPS capabilities. The system will enable full M-Code capabilities, providing jamming-resistant GPS signals for military operations in contested environments. OCX is also designed to improve cybersecurity for both military and civilian applications significantly. Once operational, OCX will command all modernized and legacy GPS satellites, managing all civil and military navigation signals.

The program has faced scrutiny due to its delays and cost overruns. The GAO has flagged the program’s delays as a risk to the GPS enterprise, while lawmakers have expressed frustration over the delays and budget increases. Despite this, the Space Force continues investing in the program to enhance GPS capabilities for military and civilian users. OCX is expected to provide improved accuracy, availability and resistance to jamming compared to the previous ground control segment. The system will also support the launch and operation of GPS III satellites.

December 10, 2024
Ligado moves forward with lawsuit against DOD

The U.S. Court of Federal Claims has allowed Ligado Networks to proceed with its $39 billion lawsuit against the federal government, marking a significant development in a long-standing dispute over 5G spectrum usage and property rights.

Judge Edward Damich partially favored Ligado by acknowledging the company’s case for property interest in the spectrum allegedly used by the Department of Defense (DOD) while rejecting its claim that the FCC license constituted a property right subject to federal taking.

The controversy stems from the FCC’s 2020 decision granting Ligado exclusive authority over spectrum near GPS frequencies, raising concerns about potential interference with GPS systems. Ligado’s October 2023 lawsuit accuses the U.S. government of conducting a “multiyear misinformation and disparagement campaign” to conceal its activities and misappropriate Ligado’s licensed spectrum for DOD systems without permission or compensation.

The government attempted to dismiss the lawsuit in January 2024, arguing lack of jurisdiction and that Ligado couldn’t establish a cognizable property interest in its FCC license. However, Judge Damich’s ruling allows the case to proceed.

At the core of this dispute is the proximity of Ligado’s L-band spectrum to GPS frequencies, raising concerns about potential interference with critical GPS signals used for navigation, timing and various applications essential for national security and economic stability. The DOD, GPS companies and industry officials have strongly opposed Ligado’s plans for a terrestrial 5G network, arguing it could cause harmful interference to GPS receivers.

December 10, 2024
Australia and India advance resilient PNT

Skykraft, an Australian space technology company, has signed a participating project partner agreement to advance positioning, navigation and timing (PNT) systems in low-Earth orbit (LEO). This agreement, backed by an International Space Investment (ISI) India Projects grant from the Australian Government, marks a significant milestone in fostering space cooperation between Australia and India.

The project’s primary objective is to develop and demonstrate collaborative PNT systems. This includes establishing the viability of large-scale LEO constellations, addressing vulnerabilities in existing GNSS in denied environments, and exploring novel applications for PNT signals from LEO. Additionally, the project aims to create a comprehensive roadmap for collaborative LEO-PNT by implementing resilient, easily updatable constellations.

The project also seeks to enhance environmental monitoring capabilities through GNSS-reflectometry (GNSS-R) and radio occultation (GNSS-RO) technologies. This will improve understanding of Earth’s oceans, droughts, and floods while enhancing real-time space and terrestrial weather forecasting. It will explore emerging applications, such as tsunami monitoring and warning systems.

December 9, 2024
GLONASS in the age of hydrogen

The development and digital transformation of the global economy are based today on high-precision time synchronization of transport management processes, the transmission of electricity and data and many other processes. The high-precision global synchronization of GNSS spacecraft signals makes global instantaneous all-weather navigation possible and is the primary solution to the problem of time transmission.

For the past 57 years, since their adoption by the International Bureau of Weights and Measures (BIPM) as a unit of time measurement in the International System of Units of the Atomic Second, the technical characteristics of atomic frequency standards have increased significantly. The universally used Coordinated Universal Time (UTC) is based on the atomic time scale (AT), the readings of which are adjusted taking into account data regarding the Earth’s rotation.

Since its inception, GLONASS has relied on basic solutions embedded in the definition of UTC(SU). AT is formed by calculating the total number of vibrations at the resonant frequency of the energy transition between the levels of the hyperfine structure of the ground state of the cesium atom (133Cs) in the absence of external influences. It was based on this substance that the first ground and airborne frequency standards for GLONASS were created.

In accordance with the system’s interface control document, GLONASS transmits Moscow Time1, which is established by law by the Russian Federation. GLONASS transmits UTC(SU), which is formed as UTC+3 hours. In recent years, much work has been done to modernize the infrastructure for the formation of the national UTC(SU) time scale2. Today, the State Standard of Time and Frequency (SSTF) of the Russian Federation is one of the most modern time synchronization centers in the world. The basis of the SSTF are hydrogen frequency and time standards (HS) of the active type. The composition of the SSTF includes a storage complex of the national time scale based on the six newest active-type HS with a daily frequency instability of 3×10-16. In total, the SSTF consists of 18 HS.

Including new HSs in the composition of the SSTF has led to a significant increase in its contribution to forming the UTC scale. Currently, 87 time standards at national time laboratories contribute to the formation of UTC, which, following the recommendations of the BIPM time department, regularly provides measurement information of standards of the established format and content. In turn, the BIPM time division forms the International Atomic Time Scale (TAI) and the UTC scale. On a monthly basis, the BIPM Time Department publishes the results of the international key comparisons CCTF-K001.UTC and other data based on which a comparative analysis of the metrological characteristics of national standards is carried out.

The ALGOS algorithm is used for the formation of TAI and UTC2. It includes two main procedures: forecasting the drift of the frequency of standards and determining the contribution of specific standards to the final result — determining the statistical weight of standards.

Figure 1: Dynamics of the contribution of the world’s major time laboratories. (All figures provided by the authors)

Starting in September 2011, forecasting of the standards’ frequencies takes into account the frequency drift inherent in hydrogen frequency standards. The procedure for determining the statistical weight of standards was also changed; preference was given to the predictability of their frequency, which showed a more balanced distribution of statistical weights and increased the contribution of hydrogen standards to the formation of TAI and UTC.

Figure 1 shows the dynamics of the contribution of the world’s main time laboratories to the formation of UTC for 2022-2024: Russia – the Main Metrological Center of the SSFT, SU; United States – Naval Observatory, USNO; China – National Time Service, NTSC; Japan – National Institute of Information and Communication, NICT; France – Paris Observatory, OP; Sweden – Technical Research Institute, SP; Germany – Institute of Physics and Technology, PTB; Poland – Time Laboratory, PL. The WT contribution of each laboratory is calculated as the sum of the weights of all frequency standards, the measurement results of which this laboratory transmits to the BIPM. The weight of each individual atomic time and frequency standard is calculated monthly by the BIPM time division when calculating TAI and UTC based on an assessment of its frequency stability over the billing period.

The main characteristic of the HS, which affects the characteristics of the formation of time scales, is the instability of the frequency of the output signals. To quantify the frequency instability of the output signals, a number of characteristics are used that reflect both random and systematic frequency changes over time. The Allan variation has been widely used for more than 50 years as the main assessment of the frequency instability of the output signals of standards in the time domain.

At the same time, in terms of frequency instability, the SSTF atomic clock also occupies a leading position. In October 2022, the average weight of atomic clocks of laboratories in the formation of TAI and UTC increased significantly, from 1 to 1.2% to 1.4 to 1.6% (the best indicator for foreign laboratories is 0.5 to 0.7%). This indicator is calculated by dividing the total contribution of each laboratory by the number of its atomic clocks that participated in the formation of TAI and UTC in the period under review. The average contribution more correctly characterizes the quality of the frequency standards of each time laboratory.

Additionally, an important indicator is the percentage of atomic laboratory clocks having the maximum allowable BIPM weight for an individual frequency standard. For 2022-2024, the figure ranged from 80% to 100%. The maximum possible weight depends on the total number of frequency standards involved in the formation of UTC in a particular billing period. This indicator was calculated as the number of atomic clocks having the maximum permissible weight divided by the total number of hours of this laboratory in each calculation period. All HSs from the SSFT have the highest rates of frequency instability and for most of the period under review make the maximum possible contribution to the formation of TAI and UTC.

Figure 2: Comparative estimates of national time scale shifts. (All figures provided by the authors)

The characteristics of the Russian HS directly impact the formation of the national atomic and coordinated time scales of the Russian Federation TA(SU) and UTC(SU). Figure 2 shows the differences between national time scales and UTC.

Coordinated Universal Time(k) relative to UTC in 2022-2024.

The analysis of this data allows us to conclude that the UTC(SU) national coordinated time scale is one of the best national implementations of UTC, and the national atomic time scale TA(SU) occupies a leading position in terms of instability among the scales implemented in the leading national time laboratories.

GLONASS’ time scale is linked to the readings of the SSTF, taking into account the correction of the Moscow decree time and are implemented by the GLONASS synchronization system, which is also based on hydrogen frequency standards. Figure 3 shows the discrepancy between the values of the GLONASS system time relative to the UTC(SU) time, which is currently less than 10 ns.

Figure 3: Error in transmitting the national time scale of the Russian Federation UTC(SU) using GLONASS. (All figures provided by the authors)

UTC(SU) parameters are transmitted via GLONASS spacecraft and the first of the fourth-generation spacecraft, which has a passive hydrogen maser (PHM) on board, was launched into operational orbit on Aug. 7, 2023. In the spring of this year, flight tests of this device began, which showed an improvement in the accuracy of time transmission during the transition from the cesium to the hydrogen standard.

Figure 4: The discrepancy between the spacecraft time scale and the UTC scale: 1 – Glonass-K2, orbit slot 26, 2 – Glonass-M, orbit slot 12. (All figures provided by the authors)

Figure 4 shows the magnitude of the discrepancy between the time scales of the two GLONASS spacecraft. The cesium frequency standard installed on board the Glonass-M shows some of the best characteristics in the entire 20-year history of these spacecraft and demonstrates a daily relative frequency instability of 2×10-14, which is five times better than the design characteristics. Preliminary results of the use of the PHM as a source of reference vibrations and time synchronization pulses on board the Glonass-K2 in the same time interval shows a decrease of more than two times in the fluctuation error of forecasting the time scale with a relative daily instability of 7 × 10-15.

Similar characteristics emerge when using the most conservative spacecraft control scenario. Here, the update of the on-board clocks parameters (OCP) of the on-board time scale departure model relative to the system is carried out once per turn, i.e. once every 11 hours and 45 minutes. This ensures a decrease in the value of the OCP contribution to the error of navigation definitions due to the space complex before updating them from 1.4 m with a daily instability of 1×10-13 to 0.1 m for a relative daily instability of 7×10-15. The results obtained make it possible to redefine the basic onboard standard and switch to the priority use of the HPM signal for the formation of reference oscillations and clock synchronization of GLONASS spacecraft signals.

Figure 5 Passive hydrogen maser VC-1017. (All figures provided by the authors)

Further development of this technology provides for installing a VC-1017 small frequency standard on board (Figure 5). Compared with the one presented in a previous article, this standard is more than two times lighter while maintaining the stability characteristics of the formation of reference vibrations (Figure 6).

Figure 6 Measured instability of the VCH-1017 frequency relative to the state primary standard of time units, frequency and Russia’s national time scale for 40 days. The frequency drift was 1.51×10-15. The daily instability with the exception of drift is 1.42×1. (All figures provided by the authors)

The launch of the Glonass-K2 spacecraft with the prototype of this HPM is planned for the first half of 2025. Its precision characteristics allow us to expect a further increase in the stability of time transmission by GLONASS.

A significant improvement in the metrological characteristics of hydrogen frequency standards is achieved using a new system for forming a beam of atoms in a single energy state, which was developed before their industrial use. Thus, the daily frequency instability in active hydrogen frequency standards using a new beam formation system reached the level of (6-8) ×10-17.

Figure 7: Microwave resonators for passive hydrogen frequency standards. (All figures provided by the authors)

The basis for creating passive frequency standards of various sizes was the pioneering invention of an oscillatory structure, which is used in all passive hydrogen frequency standards for global navigation satellite systems. This microwave resonator made it possible to change the dimensions at a constant resonant frequency of 1,420,405,751 Hz, close to the frequency of the atomic transition. At the same time, the design proved to be suitable for harsh operating conditions, including requirements for the launch of the spacecraft. (Figures 7 and 8).

Figure 8: Microwave resonators of different sizes for passive hydrogen frequency standards. (All figures provided by the authors)

Reducing the size of the “heart” of the frequency standard allows you to reduce the weight of all other structural elements — thermostats, magnetic screens, vacuum caps, supports, etc. At the same time, it is easier to achieve structural rigidity requirements and reduce the influence of destabilizing factors.
The most important factor influencing the metrological characteristics of passive hydrogen frequency standards is the automatic frequency tuning system of the quartz oscillator to the frequency of the spectral line.

Careful engineering of the auto-tuning system avoids the influence of control circuits on each other. In addition, a technical solution has been introduced in the new frequency standards of the GLONASS system, which makes it possible to reduce the impact of various factors on the stability of the output frequency.

The results obtained allow us to consider the coming year 2025 as an important milestone in the development of time transmission technologies through the GLONASS system.

December 3, 2024
Clocks, eLoran, quantum navigation and best practices – UK PNT forging ahead
Saying the government must focus on “delivering an operational resilient positioning, navigation and timing (PNT) system for the UK 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.

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

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

Still, seminar attendees were gratified to hear the minister endorse the ten-point PNT policy framework published by the previous administration in 2023. It was particularly encouraging that he also committed to operationalizing it with implemented systems.

The minister did not mention the UK’s significant investment in quantum research, which was discussed later in the seminar. This research has the potential to contribute to PNT with better timekeeping and inertial and gravimetric sensing. Three quantum hubs — one each in Scotland, the Midlands and the South — are part of this effort.

Lord Vallance, UK Science Minister. (Image: 10 Dowing Street)

Lord Vallance and Shabana Haque, Ph.D., the head of the National PNT Office, who spoke later, also mentioned two important non-technology themes.

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

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

Shabana Haque, Ph.D., head of the UK PNT Office, spoke to the RIN at its 2024 UK PNT Leadership Seminar. (Image: RIN)

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

The UK government has been working with several partners to advance its understanding and planning implementation of an eLoran capability. Haque highlighted work with the ESA’s F)!NAVISP program, resulting in the UK’s Roke developing an eLoran antenna for handheld devices. She also discussed the integration of the National Timing Centre’s clock and fiber network with eLoran signals and the development of GNSS/eLoran receivers. Of particular interest to many was an “eLoran Effectiveness Report” that the government commissioned and received from the General Lighthouse Authority’s Research and Development (GRAD) team. GRAD has had extensive experience with the technology, having operated and evaluated a differential eLoran system along Britain’s east coast for more than a year.

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

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

Available from the RIN’s Resilient PNT Por tal, 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 that PNT experts use these tools to work with customers, suppliers and partners and act as a “guiding hand.”

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

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

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

Commercial eLoran to be offered in the UK

Hellen Systems, Inc. and Arqiva have partnered to develop a commercial eLoran service in the United Kingdom. The announcement was made on the Hellen Systems LinkedIn page.

The partners seek to support critical national infrastructure, government, and military users by citing the need for “sovereign, independent, resilient” PNT alternatives.

eLoran is deployed and operating across China and South Korea. Older versions of Loran are operating in Russia and Saudi Arabia. Yet, aside from a single transmitter in the UK being used as a timing signal, operating Loran systems have been off the air in the West since the European system shut down in deference to Galileo in 2016.

In recent years, increasing interference with GNSS signals has rekindled Western interest in the technology. The European Space Agency (ESA) recently sponsored a project that produced an eLoran antenna suitable for mobile devices. Three transmitters are on-air in the U.S., presumably for testing, and the UK Ministry of Defence has issued a request for information, which is expected to lead to the purchase of a deployable eLoran system (the U.S. Air Force operated a deployable capability called Loran-D in the 1970s).

Originally developed and used in World War II, some still view Loran as old technology. Its advocates counter that today’s telephones and televisions are vastly improved over 1940s technology, and the same is true for eLoran over its older Loran-A and Loran-C versions.

A high-power terrestrial system operating at 100kHz, UK demonstrations with differential eLoran in 2014 showed an accuracy of 10 m positioning and 50 ns timing. The positioning accuracy for the previous version of Loran, Loran-C, was approximately 460 m absolute accuracy, 90 m repeatable accuracy and 5 µs.

Hellen Systems’ President, Bridge Littleton, says the partnership is “… excited to bring commercial eLoran to the UK as a unique resilient PNT capability” and cites its advantages as a secure signal able to penetrate deep indoors without the need for an external antenna. The UK frequency regulator, Ofcom, proposed offering commercial eLoran licenses in 2022 and began the process in 2023. Hellen was granted a UK spectrum license for eLoran earlier this year.

The announcement also lists Microchip, Chronos Technology, Ltd, Continental Electronics, and CGI as team members in the project.
November 26, 2024
Advanced Navigation, MBDA improve resilient navigation technology

Advanced Navigation and MBDA have partnered to co-develop a resilient navigation system that incorporates MBDA‘s NILEQ absolute positioning technology.

The collaboration aims to provide robust absolute positioning for a variety of airborne platforms, enhancing navigation reliability in both civilian and military sectors. The joint effort is part of a broader initiative to boost research and technology development between the United Kingdom and Australia, aligning with the objectives of AUKUS Pillar 2 — a component of the security partnership between Australia, the UK and the U.S. in September 2021. The partnership includes informed decision-making, strategic autonomy and heightened combat efficiency in the face of emerging threats.

This partnership underscores the importance of developing navigation technologies that are resilient against interference, especially in an era marked by increasing geopolitical tensions and electronic warfare threats such as GPS jamming and spoofing.

NILEQ technology utilizes neuromorphic sensors to identify and compare terrain fingerprints, taking inspiration from biological change detection processes. This sensing technology captures data on changing terrain as an airborne system flies over it, matching this data to an existing database of the Earth’s surface. As a result, systems such as UAVs can achieve a precise position fix on land using a passive solution that is resistant to interference, which enhances the safety of beyond visual line of sight (BVLOS) operations.

The collaboration will conclude with a real-world demonstration of the NILEQ technology in Australia, validating its effectiveness in delivering resilient navigation solutions.

November 25, 2024
BeiDou Navigation Satellite System in 2024

Successful launch of the 59th and 60th BDS satellites on Sept. 19, 2024. (Photo: International Cooperation Center of China Satellite Navigation Office)

Upholding the principles of “superior construction, excellent management, and substantial development,” the BeiDou Navigation Satellite System (BDS) implements multifaceted strategies to ensure uninterrupted and stable system operations and services, with its backup satellites launched into orbit as per the scheduled plan in 2024. Concurrently, research on next-generation BDS technology upgrades and related technological trials for integration with low-Earth orbit (LEO) positioning, navigation and timing (PNT) systems are vigorously promoted, further enhancing international collaboration and propelling the continuous advancement of BDS in the new era.

1. System operation and services

All figures provided by the author.

BDS currently consists of 45 operational satellites in orbit, delivering services through 15 BDS-2 and 30 BDS-3 satellites. Since May 2023, five BDS-3 backup satellites have been launched to bolster system resilience.

According to the monitoring data from the International GNSS Monitoring and Assessment System (iGMAS) and the International GNSS Service (IGS) in 2024, BDS achieves a service availability of 100% and exhibits a single satellite signal continuity of 99.991% per hour, with signal-in-space accuracy surpassing 0.9 meters (95%), broadcast ephemeris accuracy surpassing 0.2 m (95%), single frequency three-dimensional positioning accuracy of the B1C signal better than 6 m (95%, global average), and the B1C/B2a dual-frequency three-dimensional positioning accuracy superior to 3 m (95%). The timing accuracy is noted to be better than 10 ns (95%). The performance of the BDS PNT service has consistently met all performance requirements.

Figure 1 illustrates the spatial signal accuracy of the BDS B1C signal. Figure 2 presents the broadcast orbit accuracy of the BDS B1C signal. Figure 3 showcases BDS’ global positioning accuracy for both single-frequency and dual-frequency.

Through the BeiDou Satellite-Based Augmentation System B1C (BDSBAS-B1C) and the BeiDou Satellite-Based Augmentation System B2a (BDSBAS-B2a) signals, BDS offers single-frequency BDSBAS service that meets APV-I requirements and a dual-frequency multi-constellation service that meets CAT-I requirements for China and surrounding regions. The ionospheric grid model has been persistently refined to enhance the performance of the satellite-based augmentation services at the peripheries. Evaluation results reveal that the BDSBAS service attains a single-frequency positioning accuracy of 1.29 m (95%) horizontally and 1.99 m (95%) vertically, and a dual-frequency positioning accuracy of 0.77 meters (95%) horizontally and 1.41 m (95%) vertically.

BDS disseminates precise orbit and clock difference corrections and inter-code biases via the precise point positioning (PPP)-B2b signal, providing PPP services to China and surrounding areas. Evaluation results indicate that the BDS-only precise point positioning accuracy is 0.16 m (95%) horizontally and 0.22 m (95%) vertically, with a convergence time of less than 20 minutes.

In 2024, building upon its PNT services, BDS actively offers diversified specialized services, including regional short message communication, global short messaging, and international search and rescue. The number of user terminals for regional short message communications continues to grow. Based on inter-satellite links, global short messaging services can provide users with global random-access capabilities. These services have been applied in projects such as the Einstein Probe mission, the SVOM satellite in collaboration with France, and gravitational wave detection satellites, achieving instant return of global detection data. While six medium-Earth orbit (MEO) satellites are equipped with international maritime search and rescue payloads, the BDS return link enables transmission with a communication delay of less than 12 seconds, and a success rate of 96.82%, suitable for distress alert feedback, disaster information broadcasting and other multi-application scenarios.

The stable BDS operation ensures the consistent and rapid improvement of application industries and the expansion of application scenarios. In 2023, the total output value of China’s satellite navigation and location-based service industries reached more than RMB 530 billion, marking a growth of more than 7% compared to 2022.

2. System construction and development

In May 2023, a backup geostationary orbit (GEO) satellite was launched, followed by two additional MEO backup satellites launched in December 2023, featuring upgraded global short message communication capacity and enhanced intelligent payload technologies. These backup satellites have successfully completed in-orbit testing and are now ready to provide services as needed. In September 2024, another pair of MEO backup satellites, equipped with innovative atomic clocks and a new type of inter-satellite links, were deployed. These backup satellites improve system reliability and service performance and facilitate experimental validation for next-generation satellite technology upgrades.

To continuously enhance system service performance, BDS has developed precision and stability enhancement plans for both the ground control system and the in-orbit satellite support system. Efforts include intensifying satellite-based and ground-based multi-source data fusion analysis, conducting regular assessments of constellation and ground system statuses, and improving fault automatic diagnosis, response efficiency, and intelligence capacity.

China is actively promoting the integrated development and experimental validation of BDS and LEO satellite navigation augmentation systems. Leveraging several test satellites within the under-construction LEO constellation, experiments including GNSS+LEO FPPP have been conducted. Results demonstrate that GNSS orbit determination accuracy is better than 5 cm (1σ), and clock error determination accuracy is superior to 0.15 nss (1σ). With signal enhancement from two to three LEO satellites, PPP positioning accuracy reaches 0.3 m with a convergence time at the minute level, thereby enhancing high-precision service performance and reducing PPP convergence time.

In May 2023, China successfully launched the first BDS-3 GEO backup satellite. (Photo: International Cooperation Center of China Satellite Navigation Office)

3. International coordination and cooperation

China has been deeply involved in international satellite navigation. Since 2023, China has actively participated in a series of events under the United Nations framework, including the ICG-17 and the United Nations Workshop on the Application of Global Navigation Satellite Systems, contributing to the global advancement of satellite navigation. China has engaged in deep collaboration with system providers from the United States, Russia and the European Union to facilitate compatibility and interoperability, covering navigation signal structures, time systems, coordinate frameworks, test and assessment. Meanwhile, discussions are held with regional navigation satellite systems and emerging systems on topics of mutual interest, such as high-precision services and emergency alert services. In 2024, the BDS timing service was officially included in the Time Bulletin by the Bureau International des Poids et Mesures (BIPM), signifying international recognition of the ability to provide precise and reliable standard time services globally.

China continues to expand its international partnership with BDS. In recent years, events including the BDS/GNSS Global Partner Forum, the China-Africa BDS Cooperation Forums, the China-Arab States BDS Cooperation Forums, the China-Central Asia BDS Cooperation Forums, the International Training Workshop on BDS Technologies and Applications in the Belt and Road Countries and Regions and the International Summit on BDS Applications have been held to share the benefits of BDS/GNSS applications globally.

BDS will continue to uphold the vision of “a first-class navigation satellite system developed by China and dedicated to the world.” It will make every effort to ensure the stable operation, steady upgrades, and advancements of the system, as well as in-depth research in technologies such as low-orbit PNT and lunar PNT, furthering the commercialization, industrialization, and internationalization of BDS applications

November 15, 2024
Europe moving toward a “timing backbone” and looking for input
Citing a need for better “positioning, navigation and timing (PNT) resilience, availability and continuity,” a market consultation document from the EU’s Joint Research Center (JRC) says establishing a resilient PNT ecosystem is essential for “…EU autonomy, the economy’s overall resilience and EU global standing.” Therefore, creating this system-of-system ecosystem “… should be considered a critical priority for the EU.”

Such an approach to PNT and resilience is a major feature of the 2023 European Radio Navigation Plan.

According to the JRC, complementary (or continuous) PNT, or C-PNT, is the combination of existing space assets (GNSS) and future services that can work together in the multi-system ecosystem. This extends the service to areas where GNSS is not available and increases overall resilience.

The JRC document goes on to say, “The first step towards the creation of such a C-PNT ecosystem is the deployment of the terrestrial timing backbone.”

Such a backbone would:
- Interconnect existing Member States (MS) National Metrological Institutes (NMI) and National Research and Education Networks (NREN) architectures into a pan-European network.
- Maintain and (if possible) enhance the existing use cases (NMI, NREN and their existing commercial customers) and enable time connections to critical entities (CE), as regulated by the directive on the resilience of critical entities, while also promoting GNSS for additional resilience.
- Enable the commercial utilization of timing backbone to enhance EU competitiveness and enable further growth.
Responsibility for navigation issues with the European Union is somewhat dispersed. The European Radio Navigation Plan is developed as a staff working document published by the European Commission’s Director General for Defense, Industry and Space (DG DEIFS). This directorate implements the EU Space Programme, which is, in turn, managed by EUSPA, an EU executive agency.

At the same time the European Space Agency’s Navigation Directorate is responsible for “…positioning, navigation, and timing services of the European satellite navigation system Galileo and the augmentation system EGNOS” under agreement with EC. It is also responsible for ”…exploring future applications of navigation technologies for science and daily life.”

This latter includes the Navigation Innovation and Support Program (NAVISP). And while space is an important consideration in NAVISP, the program has funded some decidedly non-space projects such as the UK’s MarRINav effort which focused on terrestrial PNT, and development of an eLoran antenna for handheld devices.

The Joint Research Center supports a wide range of EU stakeholders for PNT efforts including DG DEFIS, ESA, member states, and pan-European organizations.

A “market consultation” may not seem to many as an affirmative step toward establishing a timing backbone for Europe. Experienced observers, though, point to the wealth of documentation both ESA and DG DEFIS have produced on the need for PNT resilience and the benefits that will accrue to member nations.

“The EU is very consultation and consensus-driven,” says timing expert Magnus Danielson at Net Insight. “So, you are not going to see the kind of top-down orders to do things as you might for a single state. Some of these decisions are made by each member state, as they should be. I am sure (European) Commission and ESA officials have seen what Sweden has done with distributed timing clocks operated by Netnoed, what the U.K. NPL is doing with its clock network, and are concerned about Russian jamming and spoofing in Ukraine and the Baltic. It’s pretty easy to connect the dots and make reinforcing PNT for Europe’s critical infrastructure and applications a priority. Working with the EC-JRC to develop this has been rewarding. Here’s hoping they move quickly enough. Several member states and friendly neighbors have already responded positively, and I sure the market consultation feedback will aid in moving decisions forward.”

The concept of a system-of-systems approach to resilient PNT that is underpinned by network timing is not a new one. The 2008 U. S. National PNT Architecture articulated such an approach, though it was never implemented. In 2020 the RNT Foundation expanded on this idea in a paper advocating a U.S. national resilient timing architecture using signals from space, fiber, and terrestrial broadcast. China’s National Timing Service Center adopted a similar strategy. Media reports indicate China has completed or will soon complete its High Accuracy, Ground-based Timing System with 20,000km of fiber, 295 timing stations, and nation-wide eLoran service.

The EU is asking for input about a European Timing Backbone and is interested in hearing from anyone, whether or not they are EU citizens.*

Visit the EU Science Hub page before Dec. 9 and take the survey.
November 13, 2024
Xona Space Systems, QASCOM advance resilient PNT

Xona Space Systems has partnered with QASCOM to integrate Xona PULSAR into QASCOM’s GNSS software-defined radio (SDR), the QN400-P. The integration is designed to strengthen positioning, navigation and timing (PNT) resiliency in the face of persistent threats.

The partnership seeks to deliver security, jamming and spoofing resistance and next-gen accuracy for industries such as UAV navigation and defense.

The QN400-P receiver offers multi-frequency, multi-constellation GNSS capabilities, including GPS and Galileo. Additionally, it includes measures for the mitigation of jamming and spoofing and is compatible with low-Earth orbit (LEO) PNT services, such as Xona’s PULSAR.

The demand for more robust, secure and accurate navigation is increasing across various industries, including agriculture, construction and autonomous systems. The integration of Xona and QASCOM technologies aims to deliver solutions for these sectors, as well as for other relevant applications and use cases.

November 12, 2024
Aerodata AG secures EASA certification for GPS anti-jamming and spoofing technology

Aerodata AG has been granted a Supplemental Type Certificate (STC) by the European Union Aviation Safety Agency (EASA) for its advanced GPS anti-jamming and anti-spoofing solution. The certification applies to installations integrated with Garmin 5000 avionics in a Cessna Citation Latitude jet.

With the growing threat of GPS jamming and spoofing in both civil and military aviation, Aerodata has developed a robust solution to offer continuous GPS availability. As attacks on GPS systems continue to increase, this anti-jamming and anti-spoofing technology is crucial in maintaining safe and reliable aviation operations.

Aerodata’s solution seeks to enhance its special mission capabilities, especially in Intelligence, Surveillance and Reconnaissance (ISR) missions and flight inspection, where continuous, highly accurate navigation is crucial.

Aerodata’s GPS Anti-Jamming and Spoofing Solution also positions Aerodata to reduce the vulnerability of its unmanned solutions to GPS interference, ensuring operational integrity across a wide range of manned and unmanned platforms. The newly certified system has undergone comprehensive testing and validation, and Aerodata is working on extending its capabilities to other aircraft platforms, targeting both civil and military applications.

November 12, 2024
Space Force’s new GPS satellites running months behind schedule

The Pentagon’s first batch of new and more capable GPS satellites, part of the GPS IIIF program, is facing significant delays. The first batch is eight to eleven months behind schedule, which the U.S. Space Force attributed to manufacturing difficulties encountered by contractor Lockheed Martin, particularly with complex components necessary for the satellites’ operation. Originally expected to be available for launch in April 2026, the first satellite’s delivery has now been pushed to November 2026.

The GPS IIIF program is a $9.2 billion initiative aimed at deploying up to 22 advanced satellites. The first ten satellites in this series are designed to enhance the GPS system with improved accuracy and jamming-resistant signals. These satellites will serve both critical defense applications, such as guiding smart bombs, and civilian uses, such as turn-by-turn navigation.

The new F-model satellites promise increased navigation accuracy, a signal compatible with similar European satellites, greater resistance to cyberattacks and jamming and civilian search-and-rescue capabilities to detect and locate emergency beacons.

“For the average driver using GPS navigation,” the new satellites will provide “enhanced route planning and navigation, reducing travel time and improving fuel efficiency” and a “consistent GPS service even in urban canyons and areas with tall buildings,” according to the Space Systems Command.

According to the US Space Force, The primary obstacle appears to be the production of the Mission Data Unit, a crucial new component for improved navigation. Bloomberg reported that the subcontractor, L3Harris Technologies, manufactures this unit and is experiencing technical issues.

Despite these setbacks, Lockheed Martin is reportedly on track to meet the contracted delivery dates, even if they miss the Space Force’s preferred “available for launch” schedule.

Lockheed Martin’s fixed-price contract includes incentives for meeting schedules and keeping costs below U.S. targets. However, the Space Systems Command has indicated that some criteria have not been met, resulting in reduced profit for Lockheed Martin. The exact amount of lost payments has not been disclosed.

The Space System Command notes that these delays occur against global inflation and supply chain challenges. While these factors have affected industries worldwide, the Space System Command emphasizes that Lockheed Martin, as the prime contractor, is responsible for managing all aspects of the GPS IIIF satellite development and production.

The GPS IIIF program remains a critical component of the U.S. Space Force’s efforts to modernize the GPS constellation, ensuring its continued reliability and effectiveness for both military and civilian applications in the face of evolving global challenges.

November 11, 2024