Analysis of the Effect of the Distance-Decreasing Attacks on GNSS Authenticated Signals

Global Navigation Satellite Systems (GNSS) are vulnerable to jamming, spoofing and replaying attacks because of their characteristics. Concerns regarding these attacks are being heightened because unmanned and autonomous vehicles become popular recently. Cryptographic methods have been proposed and are to be implemented in the Galileo and the GPS systems to counter spoofing attacks. However, replaying attacks could still potentially harm GNSS receivers by bypassing the cryptographic methods. Distance-decreasing attacks is a strong type of replay attacks: it essentially resolves, from the attacker's point of view, the issue of introducing processing delay by implementing two phases: early detection and late commit. This poster analyzes the feasibility of distance-decreasing attacks against the GNSS navigation message authenticated signals and proposes countermeasures.