Propagation Model Description
For all calculations, the Free Space path loss is computed at a given distance and frequency.
The effect of terrain is added as a supplemental loss or gain (obstruction or clearance).
For non line-of-sight cases, the obstruction loss calculation is based on the Irregular Terrain Model in the point-to-point mode.
See https://www.its.bldrdoc.gov/publications/download/82-100_ocr.pdf for details.
For line-of-sight cases, the two rays model is used. The direct path and ground reflection combine into a constructive or destructive interference.
For all cases, the elevation caracteristics of the terrain is extracted from a huge elevation database.
The geometry of the radio path also includes antenna height and takes into account the earth curvature and radio beam refraction.
Frequency, system components and environmental data are also used as input parameters to the model.
In addition to Free Space and terrain effect, a penetration loss is computed based on landcover data.
The landcover effect divide into vegetation loss and urban loss.
The total penetration loss depends on the object height and a density factor that can be adjusted for various regions.
The program will consider only the landcover that intersects the volume of the first Fresnel zone.
For coverage calculation, millions of point-to-points links are computed in order to produce a coverage image, with performance levels associated to colors.