  Unmanned aerial vehicles (UAVs) are becoming largely ubiquitous with an
increasing demand for aerial data. Accurate navigation and localization,
required for precise data collection in many industrial applications, often
relies on RTK GNSS. These systems, able of centimeter-level accuracy, require a
setup and calibration process and are relatively expensive. This paper
addresses the problem of accurate positioning and navigation of UAVs through
cooperative localization. Inexpensive ultra-wideband (UWB) transceivers
installed on both the UAV and a support ground robot enable centimeter-level
relative positioning. With fast deployment and wide setup flexibility, the
proposed system is able to accommodate different environments and can also be
utilized in GNSS-denied environments. Through extensive simulations and test
fields, we evaluate the accuracy of the system and compare it to GNSS in urban
environments where multipath transmission degrades accuracy. For completeness,
we include visual-inertial odometry in the experiments and compare the
performance with the UWB-based cooperative localization.
