DENVER, Colo., September 15, 2023 – Dr. Matthias Schäfer, CEO and co-founder of SeRo Systems, recently delivered a virtual presentation at the ION GNSS+ 2023 conference. His talk, titled "Jammer on the Horizon: A Robust Method for GPS Jammer Localization Using ADS-B Data," discussed SeRo’s latest GNSS RFI research that was conducted in collaboration with the Estonian Air Navigation Services EANS and the Estonian Consumer Protection and Technical Regulatory Authority TTJA. During his presentation, he emphasized the importance of monitoring the airspace to collect information on GNSS degradations and distributing insights to all stakeholders to ensure the safety, reliability, and integrity of GPS systems worldwide. He also detailed SeRo’s innovative process that leverages Automatic Dependent Surveillance-Broadcast (ADS-B) data to detect GPS jamming events and localize jammers.
Background
GPS signals have become essential to modern air navigation and surveillance. However, GPS has an inherent vulnerability to threats including jamming and spoofing, which can impact critical infrastructure and threaten national security. Any disruption to these signals, either intentionally or inadvertently, poses a substantial threat and jeopardizes the safety of flights and the air traffic management system.Political tensions, electronic warfare, and the ease of access to jamming equipment have led to a surge in jamming incidents. This increase in GPS Radio-Frequency Interference (RFI) in recent years has captured headlines, drawing the attention of experts and policymakers around the world. In 2020, an Executive Order on Strengthening National Resilience through Responsible Use of Positioning, Navigation, and Timing Services was issued, requiring government agencies to address these vulnerabilities. In 2022, EASA published a Safety Information Bulletin identifying regions in Europe that are experiencing increased incidents of GPS jamming and spoofing with a recommendation that ANSPs collect information on GNSS degradations and notify airlines and airspace users.
With the increased number of jamming incidents, the need for secure and robust solutions to counter this threat has become an imperative — and GPS interference detection and jammer localization are critical components in protecting the airspace. SeRo has developed an approach that addresses these issues with a combination of advanced data analysis and sophisticated algorithms. Under certain circumstances, the company can leverage ADS-B data to both detect GPS jamming events and localize the source of the interference.
Approach
ADS-B has emerged as a scalable and cost-effective source for monitoring GPS interference. ADS-B-equipped aircraft broadcast GPS-derived position information twice per second — serving essentially as flying sensors that continuously report their positions. However, it also has limitations due to data granularity and the inability to control the aircraft's routes. SeRo’s network of ground stations continuously monitors GPS integrity across airspace, recording anomalies when aircraft experience GPS interference. In the 365-day monitoring period, SeRo’s systems reported a significant number of anomalies.
Acknowledging that not all anomalies indicate GPS jamming, the company employs a multi-step filtering process to differentiate genuine interference events from unrelated anomalies, including aircraft with avionics issues, and aerobatic aircraft. By applying a clustering algorithm to detect and remove isolated anomalies, SeRo is able to significantly reduce noise in the data, leaving only potential interference events for further analysis. By analyzing that refined dataset, SeRo localizes the origin of the GPS interference through a process based on calculating radio horizons and evaluating the intersections to identify potential jammer locations.
Summary
As the threat of GPS jamming continues to evolve, the collaborative efforts of researchers and the expert communities are essential in mounting an effective defense against interference. By accurately detecting and localizing the sources of GPS interference, aviation authorities and organizations can mitigate risks and protect critical operations. SeRo’s research offers a flexible, affordable and adaptable solution that enhances the resilience of GPS systems and helps safeguard the integrity of the airspace.
For more information, click here for a copy of the SeRo presentation.
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