Long-term area coverage and radio relay positioning using swarms of UAVs

Unmanned Aerial Vehicles (UAVs) are becoming increasingly useful for tasks which require the acquisition of data over large areas. The coverage problem, i.e., the problem of periodically visiting all subregions of an area at a desired frequency, is especially interesting because of its practical applications, both in industry and long-term monitoring of areas hit by a natural disaster. We focus here on the latter scenario, and take into consideration its peculiar characteristic, i.e. the a coverage system should be resilient to a changing environment and not be dependent on pre-existing infrastructures for communication. To this purpose, we designed a novel algorithm for online area coverage and simultaneous signal relay that allows a UAV to cover an area freely, while a variable number of other UAVs provide a stable communication with the base and support in the coverage process at the same time. Finally, a test architecture based on the algorithm has been developed and tests have been performed. By comparison with a simple relay chain system, our approach employs up to 64% less time to reach a certain goal of coverage iterations over the map with only 17% worse average communication cost and no impact on the worst case communication cost.