Long Endurance Autonomous Flight for Unmanned Aerial Vehicles

This paper presents a summary of research performed at the University of Sydney towards extending the flight duration of fixed-wing unmanned aerial vehicles. A historical context to extended flight is provided and particular attention is paid to research in autonomous soaring and aerial refueling. Autonomous soaring presents a unique set of challenges whereby an aircraft must autonomously identify sources of energy in the wind field and generate trajectories to exploit these conditions to collect energy. The basic mechanisms of soaring flight are examined and methods for generating energy gaining trajectories for exploration, information gathering and patrolling missions with multiple aircraft are detailed. Aerial refueling represents a complementary approach for extending flight duration, and the challenges and current efforts towards autonomous refueling between small aircraft are also detailed.