Galileo's first civil authenticated position fix under spoofing conditions
For two hours on the afternoon of Wednesday 16 September, five operational Galileo satellites broadcasting over Europe transmitted a new encrypted signal for testing. On the ground in Andøya, Norway, and at ESA’s navigation laboratory at ESTEC, in the Netherlands, receivers successfully established their location using these encrypted signals, marking the first real-world positioning using Galileo’s upcoming Signal Authentication Service (SAS).
Satellite navigation has become essential in our lives, and consequently it has also become an increasingly attractive target for disruption. Interference with Global Navigation Satellite Systems (GNSS) such as jamming and spoofing is reported daily in many regions, including in Europe, particularly in or near conflict zones.
To stay ahead of these threats and continue responding to new user needs, Galileo is constantly evolving. One of its most significant innovations is the Signal Authentication Service, that together with the already available Open Service Navigation Message Authentication (OSNMA) will unlock a new level of protection against interference.
“By combining signal authentication and navigation message authentication, users will know they can trust the position their device is showing,” explained ESA’s Galileo Head of Engineering Joerg Hahn.
The Signal Authentication Service is the result of the close cooperation between partners in the Galileo programme. The European Commission (EC) defined the concept, while the European Space Agency (ESA) and the European Union Agency for the Space Programme (EUSPA) designed the architecture and updated the satellites and ground infrastructure to enable the new service on behalf of the European Union, Galileo’s owner.
Now, after extensive testing in laboratories and controlled environments, the new signal has proven its performance under real world conditions, at Jammertest.
Satellite navigation signals challenged
Each September, hundreds of stakeholders from across the GNSS value chain, from system architects and receiver manufacturers to end-user application developers, meet for a unique challenge: to deliberately subject their technologies to interference.
At Jammertest, Norwegian authorities broadcast a wide variety of jamming and spoofing scenarios so that participants can understand how their equipment performs under pressure and make it more resilient.
While jamming is usually countered through well-known signal power techniques, spoofing is significantly more complex and mass market equipment requires specific services such as OSNMA and SAS to ensure trust on the origin of the navigation signals.
ESA and the Commission’s Joint Research Centre took advantage of this unique opportunity to test the Signal Authentication Service under realistic conditions, demonstrating that the encrypted signal remains reliable when it matters the most.
Galileo signals: protected and precise
To establish a position, satellite navigation receivers work with two main pieces of data: the information sent by the satellites, known as the navigation message, and the ranging measurements, the time the signal takes to travel from the satellite to the receiver.
The Signal Authentication Service relies on encrypted ranging signals and is complemented by OSNMA, which enables receivers to confirm the navigation message originated in the Galileo system. OSNMA is operational since 2025 and represents Galileo’s first major upgrade to enhance its resilience to interference.
Next year, EUSPA, service provider for Galileo, in collaboration with the European Commission, the European Space Agency and industry will perform the service validation and accreditation activities for SAS, before the service is declared operational. Together, SAS and OSNMA will allow receivers to detect and reject a wide range of spoofing attacks. Both will be free to access and available worldwide.
In addition, users of Galileo’s High Accuracy Service (HAS) will also be able to benefit from these authentication features, enhancing trust in ultra-precise positioning.
“This portfolio of services makes Galileo a unique system, with advance protection features for mass market users, in addition to the already available Public Regulated Service, which provide even more robust jamming and spoofing protection capabilities for governmental users,” explained ESA Galileo Programme Manager, Miguel Manteiga Bautista.
About Galileo
Galileo is currently the world’s most precise satellite navigation system, serving billions of users around the globe since entering Open Service in 2016. All smartphones sold in the European Single Market are guaranteed Galileo-enabled. In addition, Galileo is making a difference across the fields of rail, maritime, agriculture, financial timing services and rescue operations.
The Galileo programme is managed and funded by the European Commission under the EU Space programme. ESA leads the design, development and qualification of the space and ground systems. ESA is also entrusted with research and development activities for the future of Galileo within the EU programme Horizon Europe. The EU Agency for the Space Programme (EUSPA) acts as the service provider, bringing the satellites into service and overseeing their operation and the market and application needs.
For more info about Galileo: https://www.usegalileo.eu/EN/