Path Planning for Communication UAVs Based on Payload Requirements

摘要

UAVs have been proposed as a suitable platform for providing communications nodes within ad-hoc networks. Such nodes could provide wide-area communications to mobile communications vehicles (CV) in support of military operations or large scale disasters, supplementing or replacing damaged terrestrial communications. This research considers a UAV payload which forms the hub of a network comprising multiple CV. Each CV is connected to the UAV payload by a two-way radio link. The payload can attempt to maintain an acceptable signal quality for each radio link by RF power control, but this is affected by changes in slant range due to the relative movement of the UAV and CVs. Additional factors which affect RF power are the antenna gain profile and UAV attitude. The combination of these factors can cause the RF power to change very significantly over the duration of a mission. One approach to controlling the total RF power is to move the UAV to waypoints at which the total RF power is optimised. This will help to regulate RF power and the coverage of CVs at the cost of increasing the volume of airspace required by the UAV. This paper compares a typical scenario, in which the UAV circles a central point, with an algorithm which navigates the UAV between waypoints at which RF power is locally optimised. Results show that regular movement of the UAV to positions of locally optimal payload power has a significant advantage over circling, both in terms of the total payload power required and the number of CV which can be supported. This performance improvement is obtained at the cost of increasing the airspace required by the UAV. Potential approaches for reducing the airspace requirement without significantly affecting these improvements are considered in the paper.