Beam Tracking for UAV-Assisted FSO Links With a Four-Quadrant Detector

TL;DR

This paper analyzes a ground-to-air free-space optical link with a hovering UAV using a four-quadrant detector to improve beam tracking amid hovering fluctuations, supported by mathematical analysis and simulations.

Contribution

It introduces a mathematical framework for beam tracking performance in UAV-assisted FSO links using a four-quadrant detector, considering UAV hovering fluctuations.

Findings

Performance depends on UAV stability levels.

Optimal array size minimizes tracking error.

Analytical results match Monte-Carlo simulations.

Abstract

A ground-to-air free-space optical link is studied for a hovering unmanned aerial vehicle (UAV) having multiple rotors. For this UAV, a four-quadrant array of photodetectors is used at the optical receiver to alleviate the adverse effect of hovering fluctuations by enlarging the receiver field-of-view. Extensive mathematical analysis is conducted to evaluate the beam tracking performance under the random effects of hovering fluctuations. The accuracy of the derived analytical expressions is corroborated by performing Monte-Carlo simulations. It is shown that the performance of such links depends heavily on the random fluctuations of hovering UAV, and, for each level of instability there is an optimal size for the array that minimizes the tracking error probability