Most common robotic outdoor navigation systems typically rely upon global positioning system, never the less there are several scenarios in which the GPS alone is not enough. The presence of high buildings, trees or other obstacles can cause a substantial deterioration of the estimation of the position of the robot due to blockage of line-of-sight and multipath effects. So, dealing with partially GPS-denied environments makes it necessary to develop ad hoc solutions to aid navigation. This work moves the first steps towards the development of a localization system based on drones and ultra-wide band technologies. The idea is to use three or four drones hovering above the working area of the rover where they can be localized using GPS.