Navigating the Underground: Tackling Localization Challenges for UAVs in Tunnels

In this work a survey of the issues and difficulties for Unmanned Aerial Vehicles (UAVs) in underground environments, in particular tunnels, will be carried out. In addition to not having Global Navigation Satellite System (GNSS) signal or any other type of external positioning, this kind of environment will present a number of unique constraints that make a wide range of visual-inertial (VIO), or LiDAR-inertial (LIO), localization algorithms unusable. In addition, state-of-the-art algorithms will be validated with real flight data in a tunnel and possible solutions will be offered for achieving robust and reliable localization using only the on-board. In this way, the deployment of autonomous navigation tasks in these degraded environments will be pushed.