UWB-Based Localization Systems for Multi-Robot Systems
Small unmanned aerial vehicles (UAV) have penetrated multiple domains over the past years. In GNSS-denied or indoor environments, aerial robots require a robust and stable localization system, often with external feedback, in order to fly safely. Motion capture systems are typically utilized indoors when accurate localization is needed. However, these systems are expensive and most require a fixed setup. Recently, visual-inertial odometry and similar methods have advanced to a point where autonomous UAVs can rely on them for localization. The main limitation in this case comes from the environment, as well as in long-term autonomy due to accumulating error if loop closure cannot be performed efficiently. For instance, the impact of low visibility due to dust or smoke in post-disaster scenarios might render the odometry methods inapplicable. We study and characterize an ultra-wideband (UWB) system for navigation and localization of aerial robots indoors based on Decawave's DWM1001 UWB node. The system is portable, inexpensive and can be battery powered in its totality. We show the viability of this system for autonomous flight of UAVs, and provide open-source methods and data that enable its widespread application even with movable anchor systems. We characterize the accuracy based on the position of the UAV with respect to the anchors, its altitude and speed, and the distribution of the anchors in space. Finally, we analyze the accuracy of the self-calibration of the anchors' positions. Our code is open source and available in the TIERS Github Page.
 Wang Shule, Carmen Martínez Almansa, Jorge Peña Queralta, Zhuo Zou, Tomi Westerlund, "UWB-Based Localization for Multi-UAV Systems and Collaborative Heterogeneous Multi-Robot Systems: a Survey", The 15th International Conference on Future Networks and Communications , Elsevier (2020) . (View) (Download) (arXiv)
 Carmen Martínez Almansa, Wang Shule, Jorge Peña Queralta, Tomi Westerlund, "Autocalibration of a Mobile UWB Localization System for Ad-Hoc Multi-Robot Deployments in GNSS-Denied Environments", International Conference on Localization and GNSS (ICL-GNSS 2020) , CEUR WS Proceedings (2020) . (View) (Download) (arXiv)
 Jorge Peña Queralta, Carmen Martínez Almansa, Fabrizio Schiano, Dario Floreano, Tomi Westerlund, "UWB-based System for UAV Localization in GNSS-Denied Environments: Characterization and Dataset", Preprint , arXiv (2020) . (View) (Download) (arXiv)