LongleyRice
Longley-Rice, or the Irregular Terrain Model (ITM), is a radio propagation model used to estimate signal strength for terrestrial links over irregular terrain. It was developed in 1968 by Longley and Rice. The model is designed to predict median field strength and time-varying fades for VHF/UHF and microwave paths, incorporating effects of terrain, atmospheric refractivity, diffraction, and tropospheric scattering.
Inputs to the model include the frequency, transmitter and receiver heights, transmitted power (optional), the path
The computation combines line-of-sight concepts with diffraction over terrain and long-range atmospheric effects; it uses methods
Longley-Rice is widely used in broadcast, military, and telecommunications planning and is incorporated into ITU-R P.452