Simple Satcom Gaseous Absorption Model
This is the original model used in STK Communications and STK Radar for modeling atmospheric absorption loss to ground stations. The model assumes a homogeneous atmosphere and that the communication link traverses completely through the atmosphere. One end of the communications link must be under an altitude of 5 km in order for the absorption loss to calculate. The maximum height for this model is 50 km.
The Surface values are used when calculating the gaseous absorption attenuation. This model requires that one end of the link be above the atmosphere.
The surface values set at the scenario level can be overridden using local values set in the individual facility, place, target or vehicle RF Atmosphere properties.
For more information, see Atmospheric Loss Models.