Air-to-Air Optical Wireless Communication for Small Fixed-Wing UAVs: Jitter Characterization, System Integration, and Flight Trials

Applying optical wireless communication (OWC) to small fixed-wing unmanned aerial vehicles (UAVs) is challenging due to pointing misalignment and strict size, weight, and power (SWaP) constraints. To analyze these constraints, we combine platform characterization with a custom flight attitude dataset, model UAV flight jitter from flight telemetry using a location-scale t-distribution, and derive a semi-analytical expression for the average bit error rate (BER) of inter-UAV OWC links under Gamma-Gamma turbulence. Furthermore, we propose an inter-UAV OWC scheme that combines a wide-angle optical transceiver for passive pointing tolerance, feedforward pointing compensation to mitigate optical-axis misalignment caused by continuous relative motion and rapid maneuvers, and rate adaptation to improve transmission reliability under dynamic channel fading; flight-log-driven simulations evaluate the feedforward tracking performance. Airborne flight trials validate full-duplex communication and three-node relaying among small fixed-wing UAVs, demonstrating real-time video transmission at 50 Mbps over a link distance exceeding 100 m and a three-UAV relay network at 20 Mbps over a cumulative range exceeding 300 m under dynamic cruising conditions.