## 4 Conclusions  
Summarizing, within the H2020-EUSPA project ESRIUM, test drives were performed to investigate the achievable localization accuracy in different Galileo OSNMA configurations for road vehicles with a particular focus on automated vehicles. Therefore, three mass-market GNSS receivers of the type Septentrio Mosaic-x5 were installed in a test vehicle and configured differently with respect to Galileo OSNMA. The results show that the performance of the receiver is quite good for a mass-market product. Currently, OSNMA can only authenticate Galileo satellites. Using only authenticated Galileo satellites (OSNMA strict mode), 73.2% of the solutions had a 2D position error below 20 cm during 8.5 h. For the OSNMA loose configuration (using in addition GPS satellites), by contrast, 92.55% of the solutions had a 2D localization error below 20 cm. The probability of achieving an RTK-fix solution in the OSNMA loose configuration was 97.06%. The OSNMA loose configuration is probably the performance that can be achieved in common environments with the Galileo OSNMA service when it is fully operational. In total, the results coincide with the theory that the number of satellites plays an important role regarding the accuracy of the PVT solutions that can be achieved. A medium number of satellites, around 10, using GPS and Galileo, showed already quite good performance in the results, while more are obviously preferable. The investigations showed that even longer RTK correction data outages did not necessarily lead to critical situations in terms of 2D positioning accuracy, since as long as the RTK fix can be kept, errors below 20 cm can be achieved. Therefore, it makes sense to increase the standard setting of the maximum RTK age in the receiver.  
Conceptualization, all authors; methodology, all authors; software, all authors; validation, R.L. and S.S. ([PERSON]); formal analysis, R.L. and S.S. ([PERSON]); investigation, all authors; resources, all authors; data curation, all authors; writing--original draft preparation, S.S. ([PERSON]) and R.L.; writing--review and editing, J.M.V.G., K.D.-L., [PERSON] (S.S.); visualization, R.L. and S.S. ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
This work was conducted within the scope of the ESRIUM Project, which has received funding from the European Union Agency for the Space Program under the European Union's Horizon 2020 research and innovation program and under grant agreement No 101004181. Details of the project can be found under esrium.eu. The content of this paper reflects only the authors' view. Neither the European Commission nor the EUSPA are responsible for any use that may be made of the information it contains. Virtual Vehicle Research GmbH has received funding within COMET Competence Centers for Excellent Technologies from the Austrian Federal Ministry for Climate Action, the Austrian Federal Ministry for Labour and Economy, the Province of Styria (Dept. 12) and the Styrian Business Promotion Agency (SFG). The Austrian Research Promotion Agency (FFG) has been authorized for the program management.  
**Acknowledgments:** This project was supported by the Austrian RTK service provider EPOSA (www.eposa.at (accessed on 15 May 2023)) providing their service free of charge. We would also like to thank EUSPA.  
**Conflicts of Interest:** The authors declare no conflict of interest.