Estimation of the Radio Refractivity Gradient From Diffraction Loss Measurements

The aim of this paper is to show that the gradient of the vertical radio refractivity profile of air near the ground can be estimated from measurements of electromagnetic wave strength. Diffraction can be used as the basic physical principle for non-line-of-sight radio links, where an obstacle covers some parts of the Fresnel zones, and therefore, the strength of electromagnetic wave is proportional to the ratio of coverage. The method, which is simple and easy to implement, is verified by measured data, and comparisons with meteorological measurements are presented.