Trajectory Optimization for Maximization of Laser Power Transfer to a Mobile UAV Through Turbulent Atmosphere

To extend the flight duration of unmanned aerial vehicles (UAVs), laser-powered systems have recently been proposed that can charge a flying UAV with laser beams from the ground. In this study, we analyze the potential of using a ground-based laser station to charge a fixed-wing UAV flying in a turbulent atmosphere. This introduces an important design challenge in optimizing the UAV's trajectory by jointly considering atmospheric turbulence and UAV energy consumption. To overcome this, we derive theoretical models which capture the UAV velocity and position evolution along a circular trajectory in a turbulent atmosphere. Based on the derived models, we first compute the received energy loss at the UAV that depends on the UAV velocity (variance) as well as the trajectory radius. Then, based on the received energy loss and energy consumption models of the UAV, the UAV trajectory is optimized with respect to velocity and trajectory radius to maximize the net laser power harvested by the UAV. Our results show that the optimal velocity and trajectory radius depend strongly on the levels of turbulence in the atmosphere.