The development of wireless networks allowing precise time-stamping of emitted/received packets paves the way to precise localization, which can be used for communication and coordination inside a fleet of Unmanned Aerial Vehicles (UAV). In this paper, we present the limit of Ultra-Wide Band (UWB) to perform relative positioning and UAV navigation, and we propose an architecture based on Time Difference of Arrival (TDoA), which doesn’t depend on deploying external equipment, as receivers will be embedded on the UAV itself. Results from simulation campaigns reveal that even if distance measurements lack precision to be useful, direction measurement on the other hand has enough precision, and this information allows us to reduce the number of packets exchanged to perform relative positioning.