A robust solution for preprocessing terrain profiles for use with ray-tracing propagation models

In order for ray-tracing propagation models to analyze scattering from irregular terrain, some form of preprocessing must be performed to create a linearized terrain profile to approximate the actual profile. This paper describes a preprocessing algorithm that has proven effective in working with large terrain-data files (over 2,000 points) and a 16-ray, geometric theory of diffraction propagation model. The algorithm is based upon Fermat´s principle, and it enables a quantitative evaluation of how well the linearized profile created approximates the actual terrain profile in terms of its effect on propagation. The accuracy of the fit can be adjusted to achieve a balance between overall model accuracy and propagation model execution time.