Combining Galileo’s Assisted Commercial Authentication Service (ACAS) with Vestigial Signal Search for Good Protection

Jón Winkel, Ignacio Fernandez-Hernandez, Cillian O’Driscoll

Peer Reviewed

Abstract:	Combining Assisted Commercial Authentication Service (ACAS) with additional algorithms, in particular Vestigial Signal Search (VSS), and processing in the receiver, significantly enhances the defenses against advanced spoofing attacks, including any form of meaconing. This paper compares two VSS strategies applied to Galileo ACAS. In the first one, the vestigial signal is searched across all the uncertainty period, defined by the receiver loose time synchronization parameter, which can go up to several seconds. In the second strategy, the vestigial signal is searched over a 4-ms period of uncertainty, corresponding to one E1-B/C code, and then handed over to E6.
Published in:	Proceedings of the 2024 International Technical Meeting of The Institute of Navigation January 23 - 25, 2024 Hyatt Regency Long Beach Long Beach, California
Pages:	1225 - 1234
Cite this article:	Winkel, Jón, Fernandez-Hernandez, Ignacio, O’Driscoll, Cillian, "Combining Galileo’s Assisted Commercial Authentication Service (ACAS) with Vestigial Signal Search for Good Protection," Proceedings of the 2024 International Technical Meeting of The Institute of Navigation, Long Beach, California, January 2024, pp. 1225-1234. https://doi.org/10.33012/2024.19514
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