Optimizing UAV Resupply Scheduling for Heterogeneous and Persistent Aerial Service

With the current advances in unmanned aerial vehicle (UAV) technologies, aerial vehicles are becoming very attractive for many purposes. However, currently the bottleneck in their adoption is no longer due to architectural and protocol challenges and constraints, but rather to the limited energy that they can rely on. In this article, we design two power resupply schemes under the assumption of a fleet of homogeneous UAVs. Such schemes are designed to minimize the size of the fleet to be devoted to a persistent service (i.e., carried out at all times) of a set of aerial locations. First, we consider the case where the aerial locations to be served are equidistant from an energy supply station. In that scenario, we design a simple scheduling scheme, that we name homogeneous rotating resupply (HoRR), which we prove to be feasible and exact in the sense that it uses the minimum possible number of UAVs to guarantee the permanent coverage of the aerial service locations. Then, we extend that work for the case of nonevenly distributed aerial locations. In this new scenario, we demonstrate that the problem becomes NP-hard, and design a lightweight scheduling scheme, partitioned heterogeneous rotating resupply (PHeRR), which extends the operation of HoRR to the heterogeneous case. Through numerical analysis, we show that PHeRR provides near-exact resupply schedules.