Galileo OSNMA Public Observation Phase: Signal Testing and Validation

The Public Observation (PO) test phase of the Galileo Open Service Navigation Message Authentication (OSNMA) signal is officially opened since November 15th 2021, by the European Union Agency for the Space Programme (EUSPA). During this phase, any interested users is allowed to access the Signal in Space (SIS) for testing purposes, while the crypto material needed to process the message and verify its authenticity is made available on the European GNSS Service Centre (GSC) web portal. This paper describes the processing of the Galileo E1-B navigation message, as observed during the first days of PO. The purpose is to analyze the crypto and authenticated data carried by the SIS and apply the OSNMA protocol to authenticate the navigation message. The SIS has been processed with the NGene real time software receiver which verifies the authenticity of the navigation data, before evaluating the position fix. The work is completed by an assessment of OSNMA-ready receiver performance, mainly in terms of position accuracy.