Estimating permittivity of snow in a multi-layer model using multi-ray simulation and a genetic algorithm

This paper presents a method for determining the relative permittivity of surface and sub-surface layers, such as a layer of snow on the ground and the hidden ground layers. In summer, the traditional two-ray model is expanded to three rays, where the new ray penetrates the top layer of ground until it is reflected by a change in the earth medium. In the winter, a five-ray model is used where snow covers the same ground. A genetic algorithm is used to determine the electrical characteristics of the ground and snow layers based on results from measurements taken from multiple positions and heights, in summer and winter. At a frequency of 2.35 GHz, the snow covering the ground during the winter campaign was found to have a relative permittivity of 11.3.