Aerosol attenuation model for high altitude UAV-based FSO links

Abstract

Free space optical (FSO) communication is well positioned to address connectivity needs in ground-UAV, inter-UAV and UAV-ground links. An accurate performance analysis of airborne FSO links requires the use of proper path loss models. While earlier studies have successfully modeled attenuation arising from rain, drizzle, fog, and snow, aerosols have received less attention. Aerosols are tiny particles suspended in the atmosphere. They can be found drifting in Earth's atmosphere from the stratosphere to the troposphere to the Earth's surface. In this paper, we conduct extensive simulations in MODTRAN to determine the extinction coefficient values for aerosol over the wavelength from 350 nm to 1550 nm including typical wavelengths (e.g., 690 nm, 780nm, 850nm, and 1550 nm) used in commercial FSO systems. Non-linear curve fitting is then used to obtain new closed-form expressions for extinction coefficients.