Terrain simulation for the cascaded cylinder diffraction model

An algorithm is presented which makes use of a topographical and a morphological terrain database to simulate the terrain profile along the great circle path between a transmitter and a receiver by a cascaded arrangement of circular cylinders. This idealised representation is used by the recently introduced cascaded cylinder diffraction model to predict the propagation loss along the geodesic path. Prior to making use of the terrain data, it is corrected for the earth´s curvature and for the atmospheric radio refractive index. An approximate but efficient interpolation scheme, using bi-cubic B-splines is employed to compute terrain surface heights and their first and second-order derivatives. Using these tools, a technique for detecting the prominent terrain obstacles along the geodesic profile is presented. Finally, each identified terrain feature is simulated by an optimum cylinder fit. Verification of the model is presented by comparing its predictions with experimental results