Helsinki pilot confirms gaps in drone navigation safety

A pilot study has confirmed significant concerns regarding Global Navigation Satellite System (GNSS) interference at low altitudes within the city, a critical finding for the future of urban drone operations.

The GNSS interference pilot was launched in response, among others, to reports from Helsinki’s local drone community of sudden, total loss of GNSS positioning, suggesting man-made interference is affecting airspace relevant to Unmanned Aerial Systems. GNSS is a satellite-based navigation and positioning system commonly used by drones.

While existing data from manned aircraft confirms high-altitude jamming in the Gulf of Finland region, data has so far lacking for the lower airspace essential for urban drone logistics and flights, such as longer-distance drone flights also tested in Helsinki. The pilot study was conducted by the city-owned innovation company Forum Virium Helsinki as part of the EU-funded CITYAM project. The three-year project supported cities in increasing urban air mobility responsibly. Among a policy roadmap and a landing site planning tool, the project organised multiple rounds of surveys to learn how citizens feel about drones.

Data-based recommendations for the city
For the GNSS interference pilot, a low-cost, custom-built sensor network was deployed on tall structures across the Helsinki city center, utilising a small solar panel, battery power, and a low data rate network for connectivity.

Data collected between April and November 2025 allowed the team to analyze positioning deviation and categorize interference severity. Based on the findings, the City of Helsinki should continue tracking the interferences. Forum Virium Helsinki highlighted the importance of these findings for ensuring a safe testing environment for autonomous mobility solutions. The issue directly impacts the city’s readiness to host advanced drone operations, like the healthcare logistics flights that were piloted in late 2025 as part of CITYAM.

Urban structures could block the interference
The pilot team of Forum Virium Helsinki had some ideas on how the work could be improved, which included using existing sensor networks, finding optimal locations for the interference detection sensors via urban digital twins, and improving the sensors. The initial hypothesis – that urban structures might block intentional interference signals from reaching lower altitudes further inland – is being investigated further.

The sensor pilot concluded with several recommendations for broader, real-time interference detection. You can find all recommendations, approaches, and key benefits in chapter 4.1 of the document: “UAM Use Cases & Landing Site Infrastructure – Lessons Learned from the CITYAM Lead Cities” (Deliverable 2.2 of CITYAM).

The study underscores a critical need for publicly available data and analysis regarding GNSS signal quality at low altitudes to safeguard future drone traffic.