Simplified method for estimating gaseous absorption at low elevation angles along earth-space paths

Abstract

This paper presents a new simplified technique for estimating gaseous absorption at low elevation angles along Earth-space paths, taking into account both the effects of the Earth's curvature and refraction. The refractive index of air is modeled as a negative exponential with respect to height. Gaseous absorption is evaluated by asymptotic expansion of its integral representation using Laplace's method.