Site Specific Urban Propagation Using the Variable Terrain Radiowave Parabolic Equation Model

This paper evaluates the performance of the Variable Terrain Radiowave Parabolic Equation (VTRPE) algorithm for calculating the forward electromagnetic propagation loss for a site specific dense urban environment. While the VTRPE code has proven capable of handling terrain profiles with high variability, this is the first test of the model against an urban profile, where the landscape consists of closely spaced structures with vertical walls and flat roofs. For this investigation, the geometry of the problem is limited to building profiles superimposed on a flat terrain, all with uniform (i.e. range independent) dielectric properties. The simulations consist of a transmitter fixed atop a tall building, with field loss calculations occurring at ranges greater than 2 kilometers, which includes dozens of diffraction regions. The urban city buildings are represented in the model via vertical plane terrain profiles, which are generated using a Matlab script to convert ESRI polygon data into digital elevation models (DEM). The numerical results for the VTRPE model are shown and compared to those generated by the Remcom Vertical Plane Urban Propagation (VPUP) model, both executing on the Naval Research Laboratory (NRL) Interactive Scenario Builder simulation platform.