Spain’s GMV Aerospace & Defence, together with ENAIRE, has developed a cost-effective system capable of detecting and localizing radio-frequency threats to satellite navigation, including spoofing and jamming.
Supported by the European Space Agency (ESA) NAVISP program, the STAGER (‘Sophisticated GNSS Threats Protection’) project addresses the growing challenge posed by deliberate and accidental disruptions to satellite navigation services, an issue of increasing concern for both civil and military sectors.
STAGER introduces a two-part solution designed for dense deployment around critical infrastructure. The first component is the SILENT node (spoofing identification and localization for enhanced navigation and timing), a compact monitoring unit capable of detecting and characterizing GNSS interference signals.
Built using commercial off-the-shelf, multi-constellation GNSS receivers and antennas, the unit continuously monitors satellite signals and surrounding RF activity, using several complementary techniques to detect anomalies in the GNSS signal environment. These include analysis of carrier-to-noise density ratio (C/N0) behavior, automatic gain control trends, RF spectrum monitoring, and the dispersion of carrier-phase double differences.
Together, these methods allow the SILENT unit to distinguish between nominal conditions, jamming events, and spoofing attacks. The system can also estimate the angle of arrival of interfering signals, enabling localization when multiple units are deployed across a region.
AI in the fold
The second component is VAULT (vulnerability assessment and understanding the impact of localized GNSS threats), a server-side application that aggregates and analyzes data from the SILENT network. VAULT classifies interference events using artificial-intelligence techniques, including support vector machine and variational autoencoder models, and then estimates the location of the interference source by combining angle-of-arrival measurements with power-difference-of-arrival analysis.
Beyond detection and localization, VAULT evaluates the operational impact of interference events. Using terrain data and RF propagation models, the tool estimates the affected service volume and identifies airspace or operational procedures that may be degraded by the interference source.
The system was validated through laboratory testing and open-air trials, including experiments during the Jammertest 2025 campaign. Results demonstrated reliable detection of spoofing and jamming signals and successful localization of interference sources using measurements from multiple monitoring units. In validation tests, localization errors ranged from sub-kilometer levels to several kilometers depending on geometry and measurement conditions.Presenting the results of the project at a recent ESA-hosted event, the STAGER team said their concept supports a scalable approach to GNSS resilience. By combining low-cost monitoring nodes with centralized analysis and modeling tools, the system could enable dense monitoring networks around airports, ports, or other critical infrastructure
