Deriving an estimate for the Fried parameter in mobile optical transmission scenarios

Abstract

Measuring the Fried parameter r0 (atmospheric optical coherence length) in optical link scenarios is crucial to estimate a receiver’s telescope performance or to dimension atmospheric mitigation techniques, such as in adaptive optics. The task of measuring r0 is aggravated in mobile scenarios, when the receiver itself is prone to mechanical vibrations (e.g., when mounted on a moving platform) or when the receiver telescope has to track a fast-moving signal source, such as, in our case, a laser transmitter on board a satellite or aircraft. We have derived a method for estimating r0 that avoids the influence of angle-ofarrival errors by only using short-term tilt-removed focal intensity speckle patterns.