PathProp¶
-
class
pycraf.pathprof.
PathProp
(freq, temperature, pressure, lon_t, lat_t, lon_r, lat_r, h_tg, h_rg, hprof_step, timepercent, omega=<Quantity 0. %>, d_tm=None, d_lm=None, d_ct=None, d_cr=None, zone_t=<CLUTTER.UNKNOWN: -1>, zone_r=<CLUTTER.UNKNOWN: -1>, polarization=0, version=16, delta_N=None, N0=None, hprof_dists=None, hprof_heights=None, hprof_bearing=None, hprof_backbearing=None)[source] [edit on github]¶ Bases:
pycraf.pathprof.cyprop._PathProp
Container class that holds all path profile properties.
- Parameters
- freq
Quantity
Frequency of radiation [GHz]
- temperature
Quantity
Ambient temperature at path midpoint [K]
- pressure
Quantity
Ambient pressure at path midpoint [hPa]
- lon_t, lat_t
Quantity
Geographic longitude/latitude of transmitter [deg]
- lon_r, lat_r
Quantity
Geographic longitude/latitude of receiver [deg]
- h_tg, h_rg
Quantity
Transmitter/receiver height over ground [m]
- hprof_step
Quantity
Distance resolution of height profile along path [m]
- timepercent
Quantity
Time percentage [%] (maximal 50%)
- omega
Quantity
, optional Fraction of the path over water [%] (see Table 3) (default: 0%)
- d_tm
Quantity
, optional longest continuous land (inland + coastal) section of the great-circle path [km] (default: distance between Tx and Rx)
- d_lm
Quantity
, optional longest continuous inland section of the great-circle path [km] (default: distance between Tx and Rx)
- d_ct, d_cr
Quantity
, optional Distance over land from transmitter/receiver antenna to the coast along great circle interference path [km] (default: 50000 km)
- zone_t, zone_rCLUTTER enum, optional
Clutter type for transmitter/receiver terminal. (default: CLUTTER.UNKNOWN)
- polarizationint, optional
Polarization (default: 0) Allowed values are: 0 - horizontal, 1 - vertical
- versionint, optional
ITU-R Rec. P.452 version. Allowed values are: 14, 16
- delta_N
Quantity
, optional Average radio-refractive index lapse-rate through the lowest 1 km of the atmosphere [N-units/km = 1/km] (default: query
deltaN_N0_from_map
)- N_0
Quantity
, optional Sea-level surface refractivity [N-units = dimless] (default: query
deltaN_N0_from_map
)- hprof_dists
Quantity
, optional Distance vector associated with the height profile
hprof_heights
. (default: querysrtm_height_profile
)- hprof_heights
Quantity
, optional Terrain heights profile for the distances in
hprof_dists
. (default: querysrtm_height_profile
)- hprof_bearing
Quantity
, optional Start bearing of the height profile path. (default: query
srtm_height_profile
)- hprof_backbearing
Quantity
, optional Back-bearing of the height profile path. (default: query
srtm_height_profile
)
- freq
- Returns
- ppropPathProp instance
Notes
The diffraction-loss algorithm was changed between ITU-R P.452 version 14 and 15. The former used a Deygout method, the new one is based on a Bullington calculation with correction terms.
Set
d_ct
andd_cr
to zero for a terminal on ship or on a sea platform; only relevant if less than 5 km.Per default, the values for
delta_N
andN_0
are queried from a radiometeorological map provided with ITU-R Rec. P.452 using the functiondeltaN_N0_from_map
. If you want to use your own values, you have to provide both,delta_N
andN_0
.Per default, the height-profile data are queried from SRTM data using the
srtm_height_profile
function. If you want to use your own values, you have to provide all four parameters:hprof_dists
,hprof_heights
,bearing
, andback_bearing
.If you don’t do the automatic query from SRTM data, make sure that the first element in
hprof_dists
is zero (transmitter location) and the last element is the distance between Tx and Rx. Also, the givenlon_t
,lat_t
andlon_r
,lat_r
values should be consistent with the height profile. The bearings can be set to zero, if you don’t need to calculate boresight angles.SRTM data tiles (
*.hgt
) need to be accessible bypycraf
. It is assumed that these are either present in the current working directory or in the path defined by theSRTMDATA
environment variable (sub-directories are also parsed). Alternatively, use theSrtmConf
manager to change the directory, wherepycraf
looks for SRTM data, during run-time. TheSrtmConf
manager also offers additional features such as automatic downloading of missing tiles or applying different interpolation methods (e.g., splines). For details see Working with SRTM data.