Analytic tropospheric ray-tracing model for constant refractivity gradient profiles

Prediction methods in tropospheric electromagnetic wave propagation primarily rely on ray-tracing and parabolic equation. While the parabolic equation approach represents a full-wave method of wave equation solution, ray-tracing methods make use of the ray-concept taken from physical optics. Although ray-tracing is not capable of giving exact field strength/phase in general cases, it does provide a useful tool for illustrating atmospheric refraction effects. The main advantage of the ray-tracing concept lies in the relative simplicity of its implementation. The aim of this paper is to introduce an analytic ray-based method of field amplitude/phase computation to consider the refractive properties of the atmosphere, represented by a refractive index gradient.