Flight path optimization of solar powered UAV for endurance flight

Endurance flight capability of solar powered UAV is an important element in performing various missions. In the limited conditions such as solar cell efficiency or sunray radiant quantities, an efficient operation is required to achieve continuous flight. In order to improve endurance flight capability of solar powered UAV, this study tried to optimize flight path through the use of gravitational potential energy by controlling flight altitude and through aircraft attitude control. The energy model includes the solar position, aircraft attitude, and aerodynamics characteristics, and the influence of air density and atmospheric transmittance was considered according to flight altitude change. Through a case study, energy optimization was performed for endurance flight. As a result of simulation, compared to level flight, energy acquisition increased and battery use decreased, which indicates that flight path optimization is effective for improvement of endurance flight capability.