The recent spotlighting of alternative positioning, navigation and timing technologies by weighty bodies such as the European Commission and the European Space Agency is causing more than a stir among the concerned communities, with both public and private interests now readying themselves to move beyond conventional GNSS for critical applications.
There’s little doubt that space-based GNSS technologies will remain the backbone upon which mass global positioning, navigation and timing (PNT) services are built, at least for the foreseeable future. However, awareness of their limits and vulnerabilities is leading to the development of alternative PNT (A-PNT) solutions.
An in-depth performance assessment campaign was recently completed by the Joint Research Center (JRC) of the European Commission (EC). Four companies, OPNT, 7 Solutions SL, SCPTime and GMV, demonstrated timing services, while three others, Satelles, Locata and NextNav, demonstrated timing and positioning services.
Assessment results have generated much interest and positive discussion, with the report recognizing there are viable alternatives to GNSS for PNT applications available today. This is not exactly a revelation. We knew, for example, that Locata has provided a key subsystem for the United States Air Force’s non-GPS-based positioning system since 2012 and has since worked with Ports of Auckland, NASA and others, providing highly precise, reliable PNT without relying on traditional GNSS. NextNav is deploying non-GNSS positioning solutions in urban settings in the U.S. and Europe. Other participants are implementing or planning to implement their own solutions.
Not a revelation, but the conclusions are important, serving as a potent stimulus and a clear signal that A-PNT is now a thing.
Where We Go From Here
The EC has already demonstrated its determination to shore up its GNSS-based PNT foundation. “The Commission is currently implementing new to Galileo and EGNOS signals and services that will increase resilience,” JRC’s PNT and GNSS Resilience Specialist Lukasz Bonenberg said, “while at the same time we are adopting relevant law, including Critical Entities Resilience [CER] and Network Information Security [NIS2] directives addressing critical infrastructure and cybersecurity.”
That provided for, Bonenberg said, an eventual European low Earth orbit (LEO) PNT system and the EU’s new IRIS2 satellite constellation, while focused on telecommunications, will also provide contributions to an emerging coordinated PNT infrastructure.
In the wake of its A-PNT testing campaign, the JRC has made many cogent recommendations. “One thing that we’d like to see is more support for the development of industry standards, to ensure interoperability,” Bonenberg said, “as a minimum of common reference to Universal Coordinated Time [UTC] and European Terrestrial Reference Frame [ETRF]. This would enable a seamless system of systems approach, with a mix of technologies within EU PNT.” The JRC would also like to see investigations undertaken into the feasibility of a dedicated EU terrestrial PNT spectrum band.
In 2023, the EC released the new European Radio Navigation Plan (ERNP). This second edition of the document comes after the 2016 Space Strategy for Europe, which tasked the EC with releasing “a European radio navigation plan to facilitate the introduction of global navigation satellite system applications in sectoral policies.”
This ERNP provides relevant information on PNT systems and services, their use, typical performance, strengths, weaknesses, developments, trends, challenges and opportunities, encompassing both conventional and emerging A-PNT systems. The ERNP aims to raise awareness of PNT services and to recommend actions toward increasing their resilience. It also elaborates a medium-term vision for how PNT might best evolve.
Concrete Actions
The JRC is discussing recommendations stemming from the report with stakeholders. Bonenberg said the JRC sees industry-led initiatives playing a pivotal role. A number of telecommunications companies are already taking a proactive stance, demonstrating proof of concept for non-GNSS-based resilient UTC provision.
Meanwhile, separate discussions are happening regarding possible coordinated actions involving the European National Metrology Institutes (NMIs) toward the provision of resilient timing services. The MRIs represent valuable experience in information delivery and in building collaboration across the measurement science community.
While notable progress has been made, Bonenberg said, “Predicting the precise timeline as to when we might see new A-PNT technologies put into practice in the EU is complex, given the Union’s multifaceted nature and the unique challenges that each member state faces.”
The ESA NAVISP Program
The European Space Agency’s Navigation Innovation and Support Program (NAVISP) is a funding mechanism that supports the development of new, innovative PNT concepts, techniques and systems that go beyond the use of GNSS signals and data. The program also works to maintain and improve existing capabilities and competitiveness of members’ satellite navigation systems and their PNT industries. The program has continued to release new funding, with a number of NAVISP-supported projects already producing interesting results.
Recently completed NAVISP initiatives include: the SSRoverDAB+ project, aimed at increasing the availability of high-accuracy GNSS corrections in rural regions using DAB+ (digital audio broadcasting) transmission; the AlnGNSS project, which used selected AI-enabled algorithms to demonstrate significant improvements in position, velocity and timing (PVT) performance compared to conventional GNSS-based PVT methods; and the NavIN project, which assessed an indoor navigation solution based on commercially available technologies for mobile phone users. Another NAVISP-funded project, which delivered its results in July, is GridCell.
Again, Key Infrastructure
Protecting critical infrastructure is among the first things we think of when considering a response to GNSS-based PNT vulnerability. Among our most critical infrastructure is the power grid.
GridCell, a project carried out with NAVISP funding by Fundamentals, SMPNet, Chronos Technology and the University of Strathclyde’s Power Networks Demonstration Centre, is one of several European research and development projects looking for new ways to make critical infrastructure more resilient.
GridCell comprises a new sustainable grid technology that includes the Smart Power Cell (SPC) concept, a system that seamlessly integrates local load, storage and power generation assets. With the ability to operate while connected to the grid and autonomously during failures, it can guarantee uninterrupted power supply to local consumers. Its precise, resilient timing system ensures reliable grid synchronization and transaction timestamping, making it an attractive answer for the energy industry.
Speaking at the recent GridCell final project presentation, Chronos Technology Technical Director Calum Dalmeny explained the alternative timing solution: “Because GNSS is vulnerable to jamming, spoofing, space weather and constellation errors, we wanted to use alternative sources of UTC, to provide that needed resiliency during periods of GNSS outage. Ultimately, we chose a system that combines GNSS with a back-up alternative timing source, utilizing terrestrial, low-frequency [LF] signals. LF can provide excellent sources of UTC, eLoran and Radio 4 198 kHz being examples, giving us high-power, wide-area coverage with a low-frequency ground wave.”
Former Powerline Technologies (a recent Fundamentals acquisition) CEO Brian Lasslett said, “GridCell has given us an insight into how decentralized ‘trading micro-grids’ could change the way the grid is organized. With this, we can see many new opportunities opening up, including peer-to-peer trading and local multi-vector energy grids. There are also some remaining obstacles and challenges, including further ensuring reliability, resilience and grid stability, and navigating industry governance structures and legal issues.” The next step is bridging the gap between regulation and commercial implementation.
Backing A-PNT
About the roles of public and private players, Bonenberg said, “As far as implementation costs are concerned, market forces should be deployed to create a balance between public and commercial A-PNT services. The public sector, represented by the European Commission, already plays a pivotal role in providing essential PNT services through the European GNSS programs, while also working to support consensus-building, to establish industry standards and define the relevant legal and regulatory framework.”
The private sector, as represented by those who participated in the JRC campaign, is sure to be instrumental in A-PNT development, implementation and operation. A strong collaboration between the public and private sector is essential, Bonenberg said.
A-PNT then is indeed a thing, a thing to be reckoned with, to be paid attention to, and to be invested in.
