Tropospheric Scintillation Model
Atmospheric absorption is one process that degrades the performance of a free space, optical communications link. Another is turbulence-induced atmospheric scintillation. STK uses the ITU-R P.1814 model for modeling scintillation effects.
One of the inputs of the ITU-R P.1814 model is the refractive index structure parameter, which is an important parameter for characterizing the amount of refractive index fluctuation that is present in the atmosphere (turbulence). The STK implementation of the P.1814 model provides two models for computing this input parameter:
- Constant. The constant model provides a constant refractive index structure parameter value that is independent of altitude, wavelength, etc.
- Hufnagel Valley. The Hufnagel Valley model computes the refractive index structure parameter value as a function of both altitude above ground and wind speed.
Constant Model
| Parameter | Description |
|---|---|
| Refractive Index Structure Parameter (m^-2/3) | The constant value for the refractive index structure parameter, in units m^-2/3 |
Hufnagel Valley Model
| Parameter | Description |
|---|---|
| Wind Speed | The constant ground wind speed |
| Nominal Ground Refractive Index Parameter (m^-2/3) | The nominal ground refractive index structure value in units m^-2/3 |