Figure 1: SEAMCAT Interface to the ITU-R P.452-17 model
Table 1 : ITU-R P.452-17 propagation model
Description |
Symbol |
Type |
Unit |
Comments |
Variation |
- |
boolean |
- |
Variation in path loss. |
Diffraction only |
- |
boolean |
- |
Select to compute only the diffraction component of the propagation model |
Water concentration |
ρ |
S |
g/m3 |
water vapour density (default 3 g/m3) |
Surface pressure |
P |
S |
hPa |
Surface pressure (default 1013.25 hPa) |
Refraction index gradient |
ΔN |
S |
1/km |
The average radio-refractive index lapse-rate through the lowest 1 km of the atmosphere, provides the data upon which the appropriate effective Earth radius can be calculated. Note that ΔN is a positive quantity. |
Surface temperature |
T |
S |
Degree Celsius |
Surface temperature (default 15 degree Celsius) |
Latitude |
|
S |
Degree |
Latitude of the path-centre location between Tx and Rx |
Antenna gain at the Tx |
Gt |
S |
dB |
Antenna gain of the Tx in the direction of the horizon along the great-circle interference path (dBi) |
Antenna gain at the Rx |
Gr |
S |
dB |
Antenna gain of the Rx in the direction of the horizon along the great-circle interference path (dBi) |
Sea level surface refractivity |
N0 |
S |
- |
The sea-level surface refractivity used by the troposcatter model as a measure of location variability of the troposcatter scatter mechanism. The correct values of ΔN and N0 are given by the path-centre values as derived from the appropriate maps. |
Time Percentage |
p |
D |
% |
Percentage time variability for which the basic transmission loss is not exceeded. |
Local clutter conditions at Tx/Rx |
|
|
|
Predefined set of clutter (ground-cover) categories that the user can choose from: Suburban, Dense suburban, Urban, Dense urban, High-rise urban, and Industrial zone. |
User specified clutter nominal heights at Tx/Rx |
ha_t, ha_r |
S |
m |
Clutter nominal heights specified by user if different from above |
User specified clutter nominal distance from Tx/Rx |
dk_t, dk_r |
S |
m |
Nominal clutter distances from Tx/Rx antenna, specified by user if different from above |