A Methodology for Localization in Tunnels Based on Periodic RF Signal Fadings

Tunnels represent challenging scenarios for robotics, where the hostile conditions such as the GPS-denied nature of the environment, walls uniformity, darkness and lack of features hinder essential tasks such as localization. In this paper we present a solution to this problem with a non-intrusive localization technique based on the promotion of periodic RF signal fadings. Using a radio-frequency (RF) transmitter and a receiver, the most adequate setups in order to motivate the appearance of periodic fadings are explored, and discrete and model-based localization methodologies are proposed on this basis. Simulations of radio-wave propagation in dielectric waveguides are compared to experimental results, where a quad rotor was flown in a tunnel recording the Received Signal Strength (RSS). Based on the agreement between them, we believe that filtering approaches including the propagation model can lead to a precise localization in this kind of environments.