Towards attack-resistant peer-assisted indoor localization

Abstract

Peer-assisted smartphone localization, which leverages pairwise acoustic ranging among nearby peer phones to refine location estimation, significantly pushes the accuracy limit of WiFi-based indoor localization. Unfortunately, this technique is designed for non-adversarial settings. Dishonest peers may cheat in their distance measurements. Outside attackers may interfere with the acoustic ranging by continually broadcasting interference signals. In this paper, we propose countermeasures against each of these attacks. We first present an algorithm that can identify peers that are not cheating in the current localization, by searching for devices that can be embedded into the same plane according to their pairwise distances. We also design a robust acoustic ranging method exploiting signal modulation, which can defend effectively against intentional interference of outside attackers. Experimental results demonstrate that our countermeasures can greatly improve the robustness of peer-assisted localization.