Extending the Endurance of Small Unmanned Aerial Vehicles Using Advanced Flexible Solar Cells

Most currently fielded small unmanned aerial vehicles (SUAV) have flight times limited to 90 minutes due to battery life and are often forced to work in teams of multiple craft to provide tactical level units with continuous observation of the battlefield. Continuous operations additionally place a strain on logistics trains by requiring either more batteries or fuel to support recharging. Prior theses have examined the ability of solar cells to extend the flight endurance and capabilities of SUAVs during peak sunlight conditions. This research demonstrated the viability of augmenting the on-board power supply with advanced thin-film photovoltaic (TFPV) cells made of copper-indium-gallium selenide (CIGS) over a longer period of time. The additional source of power will reduce, at times even eliminate, the demand on the lithium polymer batteries of a Raven SUAV as sunlight conditions change throughout the day. All components used in construction were commercially available, including foam wings that closely resembled the air-foil of a Raven SUAV with increased surface area. The laboratory tests used standard operating procedures from the operator’s manual and input from the training community to accurately simulate flight conditions and field use. This research demonstrates that degraded components and non-ideal sunlight conditions still provide a significant improvement over the original system for a minimal cost in money and weight. The approach is relevant to the use of the system in austere combat zones which require results in conditions that are rarely ideal. The research additionally applied projections to the capabilities of the augmenting circuitry on unmodified Raven wings and Puma SUAVs.