Ground cover data and diffraction models

Propagation effects on short radio links (less than a few tens of km) are dominated by diffraction and scatter from obstacles on or close to the link. Planning tools, particularly for mobile services, have evolved from empirical models based on statistical terrain roughness parameters to deterministic models based on detailed terrain and ground cover databases. In view of the increased possibilities for acquisition of digital topographic data, there is a definite need to relate the terrain and ground cover databases to the prediction models for which they constitute the primary input data, so that the right types of parameters are specified. The author discusses diffraction models and their performance. The use of ground cover data in the diffraction models are discussed