Date Added: Apr 2012
Chirp signals have been extensively used in radar and sonar systems to determine distance, velocity and angular position of objects and in wireless communications as a spread spectrum technique to provide robustness and high processing gain. Recently, several standards have adopted Chirp Spread Spectrum (CSS) as an underlying physical-layer scheme for precise, low-power and low-complexity real-time localization. While CSS-based ranging and localization solutions have been implemented and deployed, their security has so far not been analyzed. In this paper, the authors analyze CSS-based ranging and localization systems. They focus on distance decreasing relay attacks that have proven detrimental for the security of proximity-based access control systems (e.g., passive vehicle keyless entry and start systems).