Transmitter

Transmitter object belonging to satellite scenario

Since R2021a

Description

Transmitter defines a transmitter object belonging to a satellite scenario.

For an illustration of the signal power of a high power amplifier (HPA) and the system loss encountered at a transmitter, see Algorithms.

Creation

You can create Transmitter objects using the transmitter function of satellite, platform, groundStation, or gimbal.

Properties

Name — Transmitter name

"Transmitter idx" (default) | string scalar | string vector | character vector | cell array of character vectors

You can set this property only when calling the transmitter function. After you call the transmitter function, this property is read-only.

Transmitter name, specified as a name-value argument consisting of 'Name' and a string scalar, string vector, character vector, or a cell array of character vectors.

• If you are adding only one transmitter, specify Name as a string scalar or a character vector.

• If you are adding multiple transmitters, specify Name as a string scalar, character vector, string vector, or a cell array of character vectors. All transmitters that you add as a string scalar or a character vector are assigned the same specified name. The number of elements in the string vector or cell array of character vectors must equal the number of transmitters that you are adding. Each transmitter is assigned the corresponding name from the vector or cell array.

In the default value, idx is the ID assigned by the satellite scenario.

Data Types: char | string

ID — Transmitter ID assigned by simulator

real positive scalar

This property is set internally by the simulator and is read-only.

Transmitter ID assigned by the simulator, specified as a positive scalar.

MountingLocation — Mounting location with respect to parent

[0; 0; 0] (default) | three-element vector | matrix

Mounting location with respect to the parent object in meters, specified as a three-element vector or a matrix. The position vector is specified in the body frame of the input parent.

• If you are adding one transmitter, MountingLocation is a three-element vector. The elements specify the x, y, and z components of the Cartesian coordinates in the body frame of transmitter.

• If you are adding multiple transmitters, MountingLocation can be a three-element vector or a matrix. When specified as a vector, the same set of mounting locations are assigned to all specified transmitters. When specified as a matrix, MountingLocation must contain three rows and the same number of columns as the transmitters. The columns correspond to the mounting location of each specified transmitter and the rows correspond to the mounting location coordinates in the parent body frame.

When the AutoSimulate property of the satellite scenario is false, you can modify the MountingLocation property only when SimulationStatus is NotStarted. You can use the restart function to reset SimulationStatus to NotStarted, but doing so erases the simulation data.

Data Types: double

MountingAngles — Mounting orientation with respect to parent object

[0; 0; 0] (default) | three-element row vector of positive numbers | matrix

Mounting orientation with respect to parent object in degrees, specified as a three-element row vector of positive numbers. The elements of the vector correspond to yaw, pitch, and roll, in that order. Yaw, pitch, and roll are positive rotations about the z-axis, intermediate y-axis, and intermediate x-axis of the parent.

• If you are adding one transmitter, the MountingAngles property is a three-element vector.

• If you are adding multiple transmitters the MountingAngles property can be a three-element vector or a matrix. When specified as a vector, the same set of mounting angles are assigned to all specified transmitters. When specified as a matrix, MountingAngles must contain three rows and the same number of columns as the transmitters. The columns correspond to the mounting angles of each specified transmitter and the rows correspond to the yaw, pitch, and roll angles in the parent body frame.

When the AutoSimulate property of the satellite scenario is false, you can modify the MountingAngles property only when SimulationStatus is NotStarted. You can use the restart function to reset SimulationStatus to NotStarted, but doing so erases the simulation data.

Example: [0; 30; 60]

Data Types: double

Antenna — Antenna object associated with transmitter

scalar | vector

Antenna object associated with the transmitter, specified as either a scalar or a vector. This object can be the default gaussianAntenna object, or one from the Antenna Toolbox or Phased Array System Toolbox. The default Gaussian antenna has a dish diameter of 1 meter and an aperture efficiency of 0.65.

Antenna can be specified in transmitter as a name-value argument consisting of 'Antenna' and a scalar, antenna or phased array objects.

• If you are adding only one transmitter, Antenna must be a scalar.

• If you are adding multiple transmitters, Antenna is a vector. The same antenna is assigned to all transmitters.

SystemLoss — Total system loss in the transmitter

5 (default) | scalar | vector

Total system loss in the transmitter in dB, specified as a scalar or a vector.

System loss can be specified in transmitter as a name-value argument consisting of 'SystemLoss' and a scalar, or vector.

• If you are adding only one transmitter, specify SystemLoss as a scalar.

• If you are adding multiple transmitters are added, specify SystemLoss as a scalar or a vector. When SystemLoss is a scalar, the same SystemLoss is assigned to all transmitters. When SystemLoss is a vector, its length must equal the number of transmitter and each element of SystemLoss is assigned to the corresponding transmitter in the parent.

When the AutoSimulate property of the satellite scenario is false, you can modify the SystemLoss value while SimulationStatus is NotStarted or InProgress.

Frequency — Transmitter frequency

14e9 (default) | scalar | vector

Transmitter frequency in Hz, specified as a name-value argument consisting of 'Frequency' and a scalar or a vector.

• If you are adding only one transmitter, the Frequency must be a scalar.

• If you are adding multiple transmitters are added, the frequency value can be a scalar or a vector. All transmitters added as a scalar are assigned the same specified Frequency. The length of the vector must equal the number of transmitters added and each element of Frequency is assigned to the corresponding transmitter in the parent.

When the AutoSimulate property of the satellite scenario is false, you can modify the Frequency value while SimulationStatus is NotStarted or InProgress.

BitRate — Bit rate of transmitter

10 (default) | scalar | vector

Bit rate of the transmitter in Mbps, specified as a name-value pair consisting of 'BitRate' and a scalar or a vector.

• If you are adding only one transmitter, the bit rate value must be a scalar.

• If you are adding multiple transmitters, the bit rate value can be a scalar or a vector. All transmitters added as a scalar are assigned the same specified BitRate. The length of the vector must equal the number of transmitters added and each element of BitRate is assigned to the corresponding transmitter in the parent.

When the AutoSimulate property of the satellite scenario is false, you can modify the BitRate value while SimulationStatus is NotStarted or InProgress.

Power — Signal power at output of high power amplifier

12 (default) | scalar | vector

Signal power at the output of a high power amplifier in dbW, specified as a name-value pair consisting of 'Power' and a scalar or a vector.

• If you are adding only one transmitter, the power value must be a scalar.

• If you are adding multiple transmitters, the power value can be a scalar or a vector. All transmitters added as a scalar are assigned the same specified Power. The length of the vector must equal the number of transmitters added and each element of Power is assigned to the corresponding transmitter in the parent.

When the AutoSimulate property of the satellite scenario is false, you can modify the Power value while SimulationStatus is NotStarted or InProgress.

CoordinateAxes — Coordinate axes triad graphic object

CoordinateAxes object (default)

You can set this property only when calling coordinateAxes. After you call coordinateAxes, this property is read-only.

Coordinate axes triad graphic object, specified as CoordinateAxes object.

Links — Link analysis objects

row vector of Link objects

This property is read-only.

Link analysis objects, specified as a row vector Link objects.

Object Functions

aer	Calculate azimuth angle, elevation angle, and range of another satellite or ground station in NED frame
gaussianAntenna	Add Gaussian antennas
link	Add link analysis objects to transmitter
pattern	Plot 3-D radiation pattern of antenna
pointAt	Point transmitter or receiver at target
pointAt	Point satellite at target
coordinateAxes	Visualize coordinate axes triad of satellite scenario assets
dopplershift	Calculate Doppler shift at target asset in satellite scenario

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]
           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

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]

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 00:21:00    25-Nov-2020 00:40:00      1140         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);

Algorithms

This diagram shows the signal power of a HPA and the system loss experienced at the transmitting end.

Version History

Introduced in R2021a