Galileo SAS will complement OSNMA providing civilian users with authentication at ranging level for the Galileo E6-C signal component.
On 24/07/2025, Galileo Open Service Navigation Message Authentication (OSNMA) was declared operational, providing Galileo users with the means to verify that navigation information comes from the Galileo system itself and has not been tampered with. This was the first step for Galileo to provide authentication capabilities to civilian users. It will soon be complemented by the Galileo Signal Authentication Service (SAS), further strengthening trust in Galileo-enabled positioning, navigation and timing services.
Galileo is currently completing the qualification of the critical elements of the SAS service, the evolution of the Ground Mission Segment (GMS) and the E-GSC (European GNSS Service Centre). The GMS is responsible for the management of the cryptographic material for the encryption of the E6-C signal component. It delivers the cryptographic material in a secure way to the Galileo space segment and performs the tracking of the encrypted E6-C signal component after its encryption. The SAS server within the E-GSC generates the RECS (Re-Encrypted Code Sequences) to be provided to the SAS users via internet. The RECS files contain spreading code sequences of the Galileo E6-C signal component, which are re-encrypted with Galileo Open Service Navigation Message Authentication (OSNMA) future keys. The RECS will allow SAS users to obtain a ranging measurement of the Galileo E6-C encrypted signal component without the need to store confidential cryptographic material.
Galileo teams commenced internal testing activities of the SAS service with the encryption of the E6-C component of L3 satellites on 03/12/2025 as announced by Service Notice #21. This will be followed by additional testing supported by the encryption of the E6-C signal component in the rest of the Galileo space segment, targeted to start before the end of the year. In its final configuration, to be reached within 2026, the E6-C signal component will be encrypted for the complete Galileo constellation, with the exception of the Galileo IOV satellites (GSAT0101, GSAT0102 and GSAT0103) in support to the SAS service development. Further details will be provided via dedicated updates of the Galileo Service Notice #21.
In the coming months, the Galileo Programme will publish official documentation on the GSC website, such as interface control document and receiver guidelines, for the user implementation of the Signal Authentication Service.
About Galileo
Galileo, the EU´s Global Navigation Satellite System (GNSS), provides improved navigation, positioning and timing information. More than 4.5 billion users are already benefitting from Galileo.
The Galileo Programme is owned by the EU. The European Commission, as the Programme Manager, oversees the implementation of all activities. EUSPA is responsible for the operational management of the services, ensuring their availability, continuity and performance, and for the procurement of launch services required for the deployment and replenishment of the constellation. Galileo's system design and system evolution are entrusted by EUSPA to ESA.
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