Laser-Based Far-Field Wireless Power Transfer for UAV Recharging: Architecture and Experimental Validation of the Pointing, Sensing, and Control System

The rapid expansion of unmanned aerial vehicles (UAVs) applications in logistics, surveillance, and defense highlights the need for scalable and reliable energy delivery solutions. Conventional charging approaches constrain operational endurance and scalability, requiring frequent returns to base. This paper presents a laser-based wireless power transmission system designed to enable safe, contactless and efficient power transfer from ground to air. The main innovation of the work lies in the integration of an end-to-end architecture combining a high-power optical source, a hierarchical beam pointing framework with coarse and fine steering stages, and a receiver composed of sensing and energy conversion module mounted onboard the UAV. A further contribution is the adoption of a hybrid control strategy in which the reference position, obtained via RTK positioning, facilitates the coarse acquisition of the beam, whilst optical feedback from the receiver side enables precise alignment corrections. An experimental campaign is conducted to validate the main system functions under representative operating conditions. Beam propagation, pointing accuracy, and control response are characterized through laboratory and outdoor tests, including long-range spot measurements and closed-loop steering validation. The results demonstrate the technical feasibility of laser-based wireless energy transfer for UAV applications and provide an experimentally grounded framework for the development of persistent aerial operations in civil and defense scenarios.