Command-line Utility

Link Budget Calculator

usage: link-budget [-h] [--json] [-v] [--min-cnr MIN_CNR]
                   [--impl-margin IMPL_MARGIN] --freq FREQ --bw BW
                   [--polarization {circular,linear}]
                   (--eirp EIRP | --tx-power TX_POWER) [--obo OBO]
                   [--carrier-peb CARRIER_PEB] [--tp-bw TP_BW]
                   [--tx-dish-size TX_DISH_SIZE | --tx-dish-gain TX_DISH_GAIN]
                   [--tx-dish-efficiency TX_DISH_EFFICIENCY]
                   (--rx-dish-size RX_DISH_SIZE | --rx-dish-gain RX_DISH_GAIN)
                   [--rx-dish-efficiency RX_DISH_EFFICIENCY]
                   [--atmospheric-loss ATMOSPHERIC_LOSS]
                   [--availability AVAILABILITY] [--asi]
                   [--asi-eirp-ratio ASI_EIRP_RATIO]
                   [--asi-long-separation ASI_LONG_SEPARATION]
                   [--antenna-noise-temp ANTENNA_NOISE_TEMP]
                   [--mispointing-loss MISPOINTING_LOSS]
                   (--lnb-noise-fig LNB_NOISE_FIG | --lnb-noise-temp LNB_NOISE_TEMP)
                   --lnb-gain LNB_GAIN --rx-noise-fig RX_NOISE_FIG
                   --coax-length COAX_LENGTH [--lna-feed-loss LNA_FEED_LOSS]
                   [--rx-long RX_LONG] [--rx-lat RX_LAT]
                   [--rx-height RX_HEIGHT] [--sat-long SAT_LONG]
                   [--sat-lat SAT_LAT] [--sat-alt SAT_ALT]
                   [--slant-range SLANT_RANGE] [--ref-ellipsoid {WGS84,GRS80}]
                   [--obs-time OBS_TIME] [--sat-tle-name SAT_TLE_NAME]
                   [--sat-tle-group {active,stations,geo,intelsat,ses,iridium,iridium-NEXT,starlink,oneweb,orbcomm,globalstar,swarm,amateur,x-comm,other-comm,satnogs,gorizont,raduga,molniya,weather,noaa,goes,resource,sarsat,dmc,tdrss,argos,planet,spire,gnss,gps-ops,glo-ops,galileo,beidou,sbas,nnss,musson,military,radar,cubesat,other}]
                   [--tle-save-dir TLE_SAVE_DIR] [--tle-no-save] [--radar]
                   [--radar-cross-section RADAR_CROSS_SECTION]

General Options

--json

Print results in JSON format.

Default: False

-v, --version

show program’s version number and exit

Margin Options

--min-cnr

Target minimum carrier-to-noise ratio (CNR) in dB for the link margin computation.

--impl-margin

Implementation margin in dB accounting for the non-ideal behavior of the receiver system.

Default: 0

Frequency Options

--freq: Downlink carrier frequency in Hz for satellite signals or simply the signal frequency in Hz for radar (passively reflected) signals.
--bw, --if-bw: Nominal signal bandwidth in Hz.

Polarization Options

--polarization

Possible choices: circular, linear

Polarization of the transmitted electromagnetic wave.

Default: “linear”

Tx Power Options

--eirp

Carrier or transponder EIRP in dBW. If an output backoff is defined, this EIRP corresponds to the amplifier’s saturated operation. Otherwise, it represents the actual operating EIRP.

--tx-power

Power feeding the Tx antenna in dBW. If an output backoff is defined, this parameter represents the amplifier’s saturated output power. Otherwise, it refers to the actual Tx power.

--obo

Carrier or transponder output backoff in dB.

Default: 0

FDMA Carrier Power Options

Parameters to determine the power allocated to an FDMA carrier.

--carrier-peb: Power-equivalent bandwidth (PEB) in Hz assigned for the FDMA carrier. When provided, the EIRP computed from –eirp or –tx-power refers to the transponder, while the PEB determines the fraction of this transponder EIRP allocated to the carrier. In this case, note the output backoff must refer to the transponder, not the carrier. If the output backoff represents the carrier backoff, do not inform the carrier PEB.
--tp-bw: Transponder bandwidth in Hz, required if the PEB is provided.

Antenna Options

--tx-dish-size

Diameter in meters of the parabolic antenna used for transmission. Used when the power is specified through option –tx-power.

--tx-dish-gain

Gain in dBi of the parabolic antenna used for transmission. Used when the power is specified through option –tx-power.

--tx-dish-efficiency

Aperture efficiency of the parabolic antenna used for transmission. Determines the antenna gain when the dish is specified by size (option --tx-dish-size). Otherwise, when the gain is defined directly by option --tx-dish-gain, this parameter is used to infer the diameter of an equivalent parabolic reflector.

Default: 0.56

--rx-dish-size

Diameter in meters of the parabolic antenna used for reception.

--rx-dish-gain

Gain in dBi of the parabolic antenna used for reception.

--rx-dish-efficiency

Aperture efficiency of the parabolic antenna used for reception. Determines the antenna gain when the dish is specified by size (option --rx-dish-size). Otherwise, when the gain is defined directly by option --rx-dish-gain, this parameter is used to infer the diameter of an equivalent parabolic reflector.

Default: 0.56

Propagation Options

--atmospheric-loss

Attenuation in dB experienced through the atmosphere. It should always include the clear air attenuation, and it could include other effects such as rain and cloud attenuation. When analyzing a radar system, note this option should determine the one-way attenuation, not the two-way. When omitted, the program assumes a reasonable atmospheric attenuation based on models from ITU-R recommendations.

--availability

Target link availability in % to consider on the atmospheric attenuation model. For instance, when targeting at a 99.9% availability, the analysis is based on the atmospheric attenuation exceeded 0.1% of the time.

Default: 99

Interference Options

--asi

Include adjacent satellite interference (ASI) in the link budget considering neighbor satellites with overlapping coverage, frequency and polarization.

Default: False

--asi-eirp-ratio

Ratio between the aggregate downlink EIRP from adjacent satellites and the wanted signal’s EIRP.

Default: 1.0

--asi-long-separation

Longitudinal orbit separation in degrees between the wanted satellite and the adjacent satellite(s).

Default: 2.0

Rx Options

--antenna-noise-temp

Receive antenna’s noise temperature in K. When omitted, this parameter is derived based on the atmospheric attenuation.

--mispointing-loss

Loss in dB due to antenna mispointing.

Default: 0

--lnb-noise-fig

LNB’s noise figure in dB.

--lnb-noise-temp

LNB’s noise temperature in K.

--lnb-gain

LNB’s gain.

--rx-noise-fig

Receiver’s noise figure in dB.

--coax-length

Length of the coaxial transmission line between the LNB and the receiver in ft.

--lna-feed-loss

Loss in dB of the passive feed (typically waveguide) connecting the antenna to the LNA. Applicable when a discrete LNB is used instead of an integrated LNBF.

Default: 0

Earth Station Position Information

Note longitudes are positive east of the prime meridian and negative otherwise (west), while latitudes are positive above the equator (north) and negative otherwise (south).

--rx-long

Rx station’s longitude in degrees.

--rx-lat

Rx station’s latitude in degrees.

--rx-height

Rx station’s height in meters above mean sea level.

Default: 0

Satellite or Radar Object Position Information

Note longitudes are positive east of the prime meridian and negative otherwise (west), while latitudes are positive above the equator (north) and negative otherwise (south).

--sat-long

Longitude in degrees of the satellite or radar object.

--sat-lat

Latitude in degrees of the satellite or radar object.

Default: 0

--sat-alt

Satellite or radar object’s altitude in meters above the reference ellipsoid.

Default: 35786000.0

--slant-range

Slant path length in km between the Rx station and the satellite or reflector.

--ref-ellipsoid

Possible choices: WGS84, GRS80

Reference Earth ellipsoid to use in the computation.

Default: “WGS84”

--obs-time

Observation time for the satellite position’s prediction. Requires the ‘–sat-tle-name’ option and must be given in ISO 8601 format.

Satellite TLE Information

--sat-tle-name

Satellite name on CelesTrak’s TLE database.

--sat-tle-group

Possible choices: active, stations, geo, intelsat, ses, iridium, iridium-NEXT, starlink, oneweb, orbcomm, globalstar, swarm, amateur, x-comm, other-comm, satnogs, gorizont, raduga, molniya, weather, noaa, goes, resource, sarsat, dmc, tdrss, argos, planet, spire, gnss, gps-ops, glo-ops, galileo, beidou, sbas, nnss, musson, military, radar, cubesat, other

CelesTrak satellite group to restrict the search. When undefined, searches the entire database.

--tle-save-dir

Directory where downloaded TLE datasets should be saved.

Default: “/home/docs/.link-budget/tle”

--tle-no-save

Do not save the downloaded TLE datasets locally. A new download will be required every time.

Default: False

Radar Options

--radar

Activate monostatic radar mode so that the link budget considers the path loss to and back from object.

Default: False

--radar-cross-section

Radar cross-section of the radar object.