Five operational Galileo satellites broadcasting over Europe transmitted a new encrypted signal for two hours on the afternoon of Wednesday 16 September, and ground receivers used it to establish their positions, ESA reported on 17 September. The test took place at Andøya in Norway and at ESA's navigation laboratory at ESTEC in the Netherlands, and ESA described it as the first real-world positioning using Galileo's upcoming Signal Authentication Service (SAS).

The trial formed part of Jammertest, an annual Norwegian event at which authorities broadcast jamming and spoofing scenarios so that equipment makers and developers can see how their systems perform under interference. ESA and the European Commission's Joint Research Centre used the occasion to test SAS under realistic conditions. According to ESA, the encrypted signal remained reliable during the spoofing scenarios.

SAS is designed to work alongside Open Service Navigation Message Authentication, which lets receivers confirm that a navigation message came from Galileo and has been operational since 2025. ESA said EUSPA will carry out service validation and accreditation with the European Commission, ESA and industry next year before SAS is declared operational. Both services are to be free and available worldwide, and users of Galileo's High Accuracy Service will also be able to benefit from the authentication features.