gaussianAntenna
Description
gaussianAntenna(
adds a Gaussian antenna to each transmitter or receiver in the vector
trx
,Name=Value
)trx
and specifies options using name-value arguments. For example,
DishDiameter
=1.7 defines the diameter of the antenna dish.
adds a
Gaussian antenna to the transmitters or receivers and returns them in the vector
ant
= gaussianAntenna(___)ant
.
Examples
Determine Times of Availability for Satellite Link Between Two Ground Stations
Create a satellite scenario object.
startTime = datetime(2020,11,25,0,0,0);
stopTime = startTime + days(1);
sampleTime = 60; % seconds
sc = satelliteScenario(startTime,stopTime,sampleTime)
sc = satelliteScenario with properties: StartTime: 25-Nov-2020 StopTime: 26-Nov-2020 SampleTime: 60 AutoSimulate: 1 Satellites: [1×0 matlabshared.satellitescenario.Satellite] GroundStations: [1×0 matlabshared.satellitescenario.GroundStation] Platforms: [1×0 matlabshared.satellitescenario.Platform] Viewers: [0×0 matlabshared.satellitescenario.Viewer] AutoShow: 1
Add a satellite to the scenario.
semiMajorAxis = 10000000; % meters eccentricity = 0; inclination = 60; % degrees rightAscensionOfAscendingNode = 0; % degrees argumentOfPeriapsis = 0; % degrees trueAnomaly = 0; % degrees sat = satellite(sc,semiMajorAxis,eccentricity,inclination,rightAscensionOfAscendingNode, ... argumentOfPeriapsis,trueAnomaly,Name="Satellite");
Add gimbals to the satellite. These gimbals enable the satellite receiver antenna to steer to the first ground station, and its transmitter antenna to steer to the second ground station.
gimbalrxSat = gimbal(sat); gimbaltxSat = gimbal(sat);
Add a receiver to the first gimbal of the satellite.
gainToNoiseTemperatureRatio = 5; % dB/K systemLoss = 3; % dB rxSat = receiver(gimbalrxSat,Name="Satellite Receiver",GainToNoiseTemperatureRatio= ... gainToNoiseTemperatureRatio,SystemLoss=systemLoss)
rxSat = Receiver with properties: Name: Satellite Receiver ID: 4 MountingLocation: [0; 0; 0] meters MountingAngles: [0; 0; 0] degrees Antenna: [1x1 satcom.satellitescenario.GaussianAntenna] SystemLoss: 3 decibels PreReceiverLoss: 3 decibels GainToNoiseTemperatureRatio: 5 decibels/Kelvin RequiredEbNo: 10 decibels CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes]
Add a transmitter to the second gimbal of the satellite.
frequency = 27e9; % Hz power = 20; % dBW bitRate = 20; % Mbps systemLoss = 3; % dB txSat = transmitter(gimbaltxSat,Name="Satellite Transmitter",Frequency=frequency, ... power=power,BitRate=bitRate,SystemLoss=systemLoss)
txSat = Transmitter with properties: Name: Satellite Transmitter ID: 5 MountingLocation: [0; 0; 0] meters MountingAngles: [0; 0; 0] degrees Antenna: [1x1 satcom.satellitescenario.GaussianAntenna] SystemLoss: 3 decibels Frequency: 2.7e+10 Hertz BitRate: 20 Mbps Power: 20 decibel-watts Links: [1x0 satcom.satellitescenario.Link] CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes]
Specify the antenna specifications of the repeater.
dishDiameter = 0.5; % meters
apertureEfficiency = 0.5;
gaussianAntenna(txSat,DishDiameter=dishDiameter,ApertureEfficiency=apertureEfficiency);
gaussianAntenna(rxSat,DishDiameter=dishDiameter,ApertureEfficiency=apertureEfficiency);
Add two ground stations to the scenario.
gs1 = groundStation(sc,Name="Ground Station 1"); latitude = 52.2294963; % degrees longitude = 0.1487094; % degrees gs2 = groundStation(sc,latitude,longitude,Name="Ground Station 2");
Point gimbals of the satellite towards the two ground stations for the simulation duration.
pointAt(gimbaltxSat,gs2); pointAt(gimbalrxSat,gs1);
Add gimbals to the ground stations. These gimbals enable the ground station antennas to steer towards the satellite.
gimbalgs1 = gimbal(gs1); gimbalgs2 = gimbal(gs2);
Add a transmitter to ground station gs1
.
frequency = 30e9; % Hz power = 40; % dBW bitRate = 20; % Mbps txGs1 = transmitter(gimbalgs1,Name="Ground Station 1 Transmitter",Frequency=frequency, ... Power=power,BitRate=bitRate);
Add a receiver to ground station gs2
.
requiredEbNo = 14; % dB rxGs2 = receiver(gimbalgs2,Name="Ground Station 2 Receiver",RequiredEbNo=requiredEbNo);
Define the antenna specifications of the ground stations.
dishDiameter = 5; % meters
gaussianAntenna(txGs1,DishDiameter=dishDiameter);
gaussianAntenna(rxGs2,DishDiameter=dishDiameter);
Point gimbals of the ground stations towards the satellite for the simulation duration.
pointAt(gimbalgs1,sat); pointAt(gimbalgs2,sat);
Add link analysis to transmitter txGs1
.
lnk = link(txGs1,rxSat,txSat,rxGs2)
lnk = Link with properties: Sequence: [10 4 5 11] LineWidth: 2 LineColor: [0.3922 0.8314 0.0745]
Determine the times when ground station gs1
can send data to ground station gs2
via the satellite.
linkIntervals(lnk)
ans=4×8 table
Source Target IntervalNumber StartTime EndTime Duration StartOrbit EndOrbit
______________________________ ___________________________ ______________ ____________________ ____________________ ________ __________ ________
"Ground Station 1 Transmitter" "Ground Station 2 Receiver" 1 25-Nov-2020 00:20:00 25-Nov-2020 00:40:00 1200 NaN NaN
"Ground Station 1 Transmitter" "Ground Station 2 Receiver" 2 25-Nov-2020 03:19:00 25-Nov-2020 03:36:00 1020 NaN NaN
"Ground Station 1 Transmitter" "Ground Station 2 Receiver" 3 25-Nov-2020 06:15:00 25-Nov-2020 06:36:00 1260 NaN NaN
"Ground Station 1 Transmitter" "Ground Station 2 Receiver" 4 25-Nov-2020 22:20:00 25-Nov-2020 22:38:00 1080 NaN NaN
Visualize the link by using the Satellite Scenario Viewer.
play(sc);
Input Arguments
trx
— Transmitter or receiver
scalar | vector
Transmitter or receiver object to which the Gaussian antenna is added, specified as either a scalar or a vector.
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: 'DishDiameter'=1.7
sets the dish diameter of the antenna to
1.7 meters upon creation.
DishDiameter
— Diameter of the antenna dish
1
(default) | scalar | vector
This property is read-only.
You can set this property only when calling gaussianAntenna
.
After you call gaussianAntenna, this property is read-only.
Diameter of the Gaussian antenna dish in meters, specified as a scalar or a vector.
If
DishDiameter
is a scalar, the same value is assigned to all transmitters or receivers intrx
.If
DishDiameter
is a vector, the length of the vector must equal that oftrx
, and each transmitter or receiver intrx
is assigned the corresponding element in theDishDiameter
vector.
ApertureEfficiency
— Aperture efficiency of Gaussian antenna
0.65
(default) | scalar in the range (0,1] | vector
This property is read-only.
You can set this property only when calling gaussianAntenna. After you call gaussianAntenna, this property is read-only.
Aperture efficiency of the Gaussian antenna, specified as a scalar in the range (0,1].
If
ApertureEfficiency
is a scalar, the same value is assigned to all transmitters or receivers intrx
.If
ApertureEfficiency
is a vector, the length of the vector must equal that oftrx
, and each transmitter or receiver intrx
is assigned the corresponding element in theApertureEfficiency
vector.
Output Arguments
ant
— Gaussian antenna
scalar | vector
Gaussian antenna object added to the specified transmitter or receiver, returned as either a scalar or a vector.
Note
When the AutoSimulate
property of satellite scenario is false
, you
can call the gaussianAntenna
function only when SimulationStatus
is NotStarted
. You can use the restart
function to reset the SimulationStatus
to NotStarted
, but doing so erases the
simulation data.
Algorithms
The Gaussian antenna approximates a parabolic reflector using a Gaussian curve as
gain(theta) = boresightGain*exp(-(4*log(2)*((theta/3dBbeamwidth)^2)))
Note that log(2) is a natural log, where:
boresightGain = rho_a*((pi*d/lambda)^2)
-
3dBbeamwidth = 70*lambda/d
(in degrees)
theta is the angle between the direction in which the gain is computed and the boresight direction is in degrees.
rho_a is the aperture efficiency.
d is the dish diameter in meters.
lambda is the wavelength in meters.
The gain in dBi is
gain_dBi(theta) = 10*log10(gain(theta)
Version History
Introduced in R2021a
See Also
Objects
Functions
hide
|show
|play
|satellite
|access
|groundStation
|receiver
|transmitter
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