itmlogic.diffraction_attenuation package

Submodules

itmlogic.diffraction_attenuation.adiff module

itmlogic.diffraction_attenuation.adiff.adiff(d, prop)[source]

Returns adiff1 given input parameters. All parameters may not be needed.

The diffraction region is beyond the smooth-earth horizon and short of where troposhpheric scatter takes over. It is an essential region and associated coefficients must be computed.

The function adiff finds the ‘diffraction attenuation’ at the distance d, using a convex combination of smooth earth diffraction and double knife-edge diffraction (Eqn 4.11 of “The ITS Irregular Terrain Model, version 1.2.2: The Algorithm”). A call with d = 0 sets up initial constants.

Parameters:
  • d (float) – Distance in meters.
  • prop (dict) – Contains all input propagation parameters
Returns:

  • adiff1 (float) – Returns the estimated diffraction attenuation.
  • prop (dict) – Contains all input and output propagation parameters.

itmlogic.diffraction_attenuation.aknfe module

itmlogic.diffraction_attenuation.aknfe.aknfe(v2)[source]

Returns the attenuation due to a single knife edge - the Fresnel integral (in decibels, Eqn 4.21 of “The ITS Irregular Terrain Model, version 1.2.2: The Algorithm” – see also Eqn 6.1) evaluated for nu equal to the square root of the input argument.

Parameters:v2 (float) – Input for computing knife edge diffraction.
Returns:aknfe1 – Attenuation due to a single knife edge.
Return type:float

itmlogic.diffraction_attenuation.fht module

itmlogic.diffraction_attenuation.fht.fht(x, pk)[source]

Supporting function for the height gain in the “three radii method” used in the computation of diffractive attenuation, as described in equations (4.20) and (6.2)-(6.7) of “The ITS Irregular Terrain Model, version 1.2.2: The Algorithm” with inputs corresponding to the “x” and “K” parameters of these equations.

Parameters:
  • x (float) – x parameter specified in equations (4.20) and (6.2)-(6.7) of “The ITS Irregular Terrain Model, version 1.2.2: The Algorithm”
  • pk (float) – k parameter specified in equations (4.20) and (6.2)-(6.7) of “The ITS Irregular Terrain Model, version 1.2.2: The Algorithm”
Returns:

fht1 – Estimated diffractive attenuation.
Return type:

float