In recent years, the threat of spoofing — the transmission of false signals intended to deceive satellite navigation receivers — has become increasingly prominent.
A growing number of navigation users, including those in civil aviation, are experiencing position errors of hundreds of kilometres on a daily basis, often without realising it. This is particularly common in sensitive regions such as the Baltic Sea, the Black Sea, and parts of the Middle East.
In response to this growing challenge, Galileo, the European Global Navigation Satellite System (GNSS), has developed and is now launching a pioneering capability: Open Service Navigation Message Authentication (OSNMA). This new feature officially became operational on Thursday, 24 July 2025.
What is OSNMA?
OSNMA enables Galileo satellites to transmit a “digital signature” along with their standard Open Service navigation data. This signature allows receivers to verify that the signal they are receiving genuinely originates from Galileo and not from a malicious or spoofed source. Receivers equipped to fully exploit OSNMA will enjoy significantly improved protection against spoofing attacks.
A Collective European Effort
OSNMA is the result of over a decade of dedicated effort aimed at positioning Galileo at the forefront of satellite navigation. It reflects the strength of collaboration among European institutions and industry. The implementation involves the EU Space Programme Agency (EUSPA), responsible for OSNMA operations via the European GNSS Service Centre in Torrejón, Madrid; the European Space Agency (ESA), which manages the Galileo core infrastructure; and numerous key industrial partners from across the European aerospace sector.
The European Commission’s Directorate-General for Defence Industry and Space (DG DEFIS), and particularly its Satellite Navigation Unit, initiated, conceptualised, and oversees the implementation of OSNMA, and is responsible for overall Galileo Programme Management.
Operational Readiness
While Galileo satellites have been transmitting OSNMA since 2021 in a test mode, the service lacked formal guarantees. That changed on 24 July 2025, when OSNMA officially transitioned to operational status. The four-year testing phase has allowed users to build confidence in the service, and many consumer and professional GNSS receivers will be OSNMA-compatible from the outset.
OSNMA is already being adopted by strategic users, including the Smart Tachograph, which is installed in all trucks operating within the EU. The International Civil Aviation Organization (ICAO) has also recently initiated the process to standardise the use of Galileo OSNMA in future civil aviation aircraft.
Looking Ahead
OSNMA has been designed to operate efficiently, using spare capacity within the existing Galileo system to facilitate rapid implementation with minimal impact. In the near future, Galileo will expand its portfolio with additional services such as the Public Regulated Service (PRS) and the Signal Authentication Service (SAS). These developments will pave the way for the enhanced capabilities of the Galileo Second Generation in the coming decades.
Together with flagship initiatives like Copernicus and IRIS², Galileo OSNMA reinforces the European Union’s commitment to strategic resilience, technological sovereignty, and global leadership in space.
