A feedback motion strategy applied to a UAV to work as an autonomous relay node for maritime operations

One important aspect that needs to be carefully considered in maritime operations using unmanned robotic vehicles is the communication restrictions between the vehicles and the mission controller that arises mainly due to long distances and/or low power transmissions. This paper addresses the problem of maintaining a communication link between a command station and an Unmanned Aerial Vehicle (UAV) with limited communication range during maritime operations. The proposed scheme uses an additional UAV that acts as a relay for the communication between the command station and the UAV in mission and is actively driven to maintain a desired Quality-of-Service (QoS) level, defined in this paper. Exploiting this architecture, it is possible to plan a maritime operation for a robotic vehicle without the need of considering vehicle-to-command-station communication constraints that will be satisfied by the introduction of the extra autonomous relay-UAVs. To this end, we propose a feedback strategy that has the dual task of commanding and optimizing the execution of the relay UAV motion tasks and adapting the scheduler algorithm according to a desired QoS level. The performance of the proposed strategy is illustrated through computer simulations and preliminary experimental results.