A European Defence Agency (EDA) project has shown that unmanned aircraft can navigate reliably over land without satellite signals, according to the European Defence Agency. The result marks progress towards drones that keep operating when satellite signals are jammed, disrupted or denied.
Trials at REPMUS 2026
Engineers tested the technology in September at the 2026 Robotic Experimentation and Prototyping using Maritime Unmanned Systems (REPMUS) exercise. The event took place in the Troia area of Portugal, south of Lisbon. The trials form part of the Unmanned Aircraft Systems Single European Sky eXperimental Integration (USESXI) project. The project seeks a resilient positioning, navigation and timing solution for unmanned aircraft when Global Navigation Satellite Systems (GNSS) are unavailable, degraded or subject to interference.
Spanish companies GMV and Indra are carrying out USESXI, a €1.2 million project that runs until 2028. Their AIRSENSE navigation system combines sensors with artificial intelligence to read the environment and hold a position without satellites.
Real-time processing on board
The aircraft flew more than 100 kilometres from its ground control station and climbed to 2,100 metres. Teams assessed how well the system captures images, transmits data and keeps its sensors synchronised. They also examined whether it could support flights beyond visual line of sight.
The key achievement was running the image-based navigation software on the aircraft in real time. Processing data after the flight, or at the ground station, would depend on a data link. That dependency creates a weakness in demanding frontline conditions.
Strong over land, weaker at sea
The system stayed close to the aircraft’s true position over land without satellite signals. This shows that several navigation sources, paired with advanced algorithms, can deliver a reliable position when GNSS cannot be trusted.
Over water, performance dropped because the software found too few landmarks to recognise. EDA will concentrate on land operations, reflecting lessons from current conflicts, so the limitation does not affect project priorities.
Next steps
The team tested the system on a commercially available drone already serving with the Spanish Army. The next phase will develop it into a complete system that meets the required standards for operational use. EDA has co-organised REPMUS since 2024, and the system will return for testing at the 2027 exercise.
Learn more on the European Defence Agency website
