Pointing errors and fade statistics associated with a laser satellite communication system

摘要

Abstract: Estimates of the fractional fade time, expected number of fades, and mean duration of fade time associated with a transmitted Gaussian-beam wave are analyzed for both uplink and downlink laser satellite-communication channels and compared with similar results based on spherical wave (uplink) and plane wave (downlink) models. Weak fluctuation theory using the lognormal model is applicable for zenith angles less than 60$DGR@. Because spot size and off-axis scintillations are significant in the Gaussian-beam wave model, pointing errors become an important consideration in a reliable laser communication link. Off-axis scintillations increase even more rapidly for large diameter beams and can in some cases lead to a scintillation saturation for pointing errors greater than 1 $mu@rad off the optical beam axis.!14