OSNMA-SDR-SIM: An Open-Source Tool for Generating OSNMA-Enabled Galileo Satellite Signal

Haiyang Wang, Yuanyu Zhang, Xinghui Zhu, Ji He, Shuangrui Zhao, Yulong Shen

Peer Reviewed

Abstract:	To defend against increasingly severe GNSS signal spoofing attacks, Galileo satellite navigation system has introduced the Open Service Navigation Message Authentication (OSNMA). Although OSNMA is a free service, receiver manufacturers must develop compatible receivers capable of decoding and verifying OSNMA data, as well as evaluate the performance of their implementations and test receiver effectiveness under complex scenarios. Traditional commercial signal generators can simulate challenging environments but do not support OSNMA. The European Union Agency for the Space Programme (EUSPA) has released some test vectors that can only test whether a receiver supports OSNMA functionality. Consequently, researchers had to collect genuine Galileo signals in realistic environments for evaluation, incurring additional labor and logistical costs. To address these limitations, this paper introduces “OSNMA-SDR-SIM”, a tool for generating and transmitting OSNMA-enabled Galileo signals. Our tool allows users to specify arbitrary target positions and times, and then automatically generates and transmits real-time Galileo signals embedded with valid OSNMA data. This provides researchers and receiver manufacturers with enhanced flexibility in conducting thorough OSNMA performance evaluations. We evaluated OSNMA-SDR-SIM with two USRP B210 devices, open-source GNSS-SDR (a GNSS software-defined receiver), and OSNMALib (an implementation of OSNMA protocol). Experimental results demonstrate that OSNMA-SDR-SIM can successfully generate Galileo signals for arbitrary positions and times. GNSS-SDR processes these signals to calculate matching position and time solutions, and OSNMALib successfully authenticates the embedded OSNMA data. Finally, we release our implementation as open source for further development.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	3184 - 3192
Cite this article:	Wang, Haiyang, Zhang, Yuanyu, Zhu, Xinghui, He, Ji, Zhao, Shuangrui, Shen, Yulong, "OSNMA-SDR-SIM: An Open-Source Tool for Generating OSNMA-Enabled Galileo Satellite Signal," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 3184-3192. https://doi.org/10.33012/2025.20300
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