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bistaticTransmitter

Create bistatic transmitter

Since R2025a

    Description

    bistaticTransmitter creates a bistatic transmitter object. Bistatic radar systems have separate transmitter and receiver elements that are not co-located. To create a bistatic radar that supports synchronous, asynchronous, and multiple transmitter and receiver pairs, use bistaticReceiver in conjunction with bistaticTransmitter.

    Use the transmit object function to transmit and propagate signals from the bistatic transmitter. Specify propagation paths in the radar mounting frame, including path loss, using the propPaths. You can use the bistaticFreeSpacePath function to calculate the bistatic propagation paths, propPaths. The nextTime object function returns the leading edge of the next transmission.

    For a typical bistatic workflow, construct the bistatic transmitter using bistaticTransmitter and construct the bistatic receiver using bistaticReceiver. Then, transmit the waveform by calling transmit on the bistatic transmitter. Finally, call receive on the bistatic receiver to receive the propagated signal returned by transmit. For a more advanced workflow that supports multiple transmitters and parallelization, call collect on the bistatic receiver to coherently combine the transmitted signal returned by transmit prior to calling receive. See Transmit, Collect, and Receive Timing Visualization for more information on simulation timing and using information provided by nextTime.

    Creation

    Description

    TX = bistaticTransmitter creates a bistatic transmitter object with default values, TX, that is used to generate samples of a transmitted signal in the direction of the receiver and targets. Call transmit on TX to transmit and propagate signals.

    TX = bistaticTransmitter(PropertyName=Value) creates a bistatic transmitter object, TX, with each specified PropertyName set to the corresponding Value. You can specify additional pairs of arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN.

    example

    Properties

    expand all

    Radar waveform, specified as a phased.RectangularWaveform, phased.LinearFMWaveform, phased.PhaseCodedWaveform, phased.SteppedFMWaveform, phased.NonlinearFMWaveform, phased.CustomFMWaveform, phased.FMCWWaveform, or phased.MFSKWaveform waveform object. The default waveform is a phased.RectangularWaveform object with default values.

    Radar transmitter, specified as a phased.Transmitter System object™. The default transmitter is a phased.Transmiter system object with default values.

    Radar transmit antenna, specified as a phased.Radiator System object. The default radiator is a phased.Radiator system object with default values. The Polarization property of the phased.Radiator must be set to "None". Polarization properties "Dual" and "Combined" are not supported.

    Initial transmit time of the first transmitted waveform, specified as a non-negative scalar in units of seconds. The default value is 0 seconds.

    Data Types: double

    This property is read-only.

    IsTransmitting indicates the transmitting status of the bistaticTransmitter object, specified as true or false. When IsTransmitting is set to true, a waveform is transmitting. When IsTransmitting is set to false, zeros are transmitting.

    Data Types: logical

    This property is read-only.

    SimulationTime indicates the current simulation time of the bistaticTransmitter, specified in units of seconds.

    Data Types: logical

    Object Functions

    transmitTransmit signals for receiver and target paths
    nextTimeStart time of the next window

    Examples

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    This example shows how to create a simple bistatic scenario with a moving target. Transmit and collect pulses until the completion of 1 receive window and plot the results.

    Configure the bistatic transmitter and receiver. Use a pulse repetition frequency of 1000 Hz.

    prf   = 1e3;
    wav   = phased.LinearFMWaveform(PRF=prf,PulseWidth=1e-5);
    ant   = phased.SincAntennaElement(Beamwidth=10);
    tx    = bistaticTransmitter(Waveform=wav, ...
          Transmitter=phased.Transmitter(Gain=20), ...
          TransmitAntenna=phased.Radiator(Sensor=ant));
    rx    = bistaticReceiver( ...
          ReceiveAntenna=phased.Collector(Sensor=ant), ...
          WindowDuration=0.005);
    freq  = tx.TransmitAntenna.OperatingFrequency;

    Create bistatic transmitter and bistatic receiver platforms spaced 10 km apart and add a target platform. Use radarScenario to crreate the platforms for this example. Define the transmitter platform, receiver platform, and target platform using platform and give the target a trajectory.

    scene  = radarScenario(UpdateRate=prf);
    platform(scene,Position=[-5e3 0 0], ...
           Orientation=rotz(45).');          
    platform(scene,Position=[5e3 0 0], ...
           Orientation=rotz(135).');        
    traj   = kinematicTrajectory( ...
           Position=8e3*[cosd(60) sind(60) 0],Velocity=[0 150 0]);
    tgtPlat= platform(scene,Trajectory=traj);

    Create an empty plot.

    hFig  = figure;
    hAxes = axes(hFig); 

    Transmit and collect pulses for one receive window. First, update platform positions by calling advance on the scene and then get the platform positions using platformPoses. Next, get the propagation paths using bistaticFeeSpacePath. Then, transmit the signal and receive pulses. Finally, plot the received signals.

    t    = nextTime(tx);
    tEnd = nextTime(rx); 
    while t < tEnd
        advance(scene);   
        % Get platform positions
        poses = platformPoses(scene); 
    
        % Calculate paths
        proppaths = bistaticFreeSpacePath(freq, ...
                  poses(1),poses(2),poses(3)); 
    
        % Transmit
        [txSig,txInfo] = transmit(tx,proppaths,t);
    
        % Receive pulses 
        [iq,rxInfo] = receive(rx,txSig,txInfo,proppaths);
        t = nextTime(tx);
    
        % Plot received signals
        rxTimes = (0:(size(iq,1) - 1))*1/rxInfo.SampleRate ...
                + rxInfo.StartTime;   
        plot(hAxes,rxTimes,mag2db(abs(sum(iq,2))))  
                hold(hAxes,'on')
    end

    Label the plot.

    grid(hAxes,'on')
    xlabel(hAxes,'Time (sec)')
    ylabel(hAxes,'Power (dB)')
    axis(hAxes,'tight')

    Figure contains an axes object. The axes object with xlabel Time (sec), ylabel Power (dB) contains 4 objects of type line.

    This example shows how to create a bistatic scenario with two bistatic transmitters. The receiver is located between the transmitters and there is a target with a custom radar cross section. Transmit and collect pulses for four receive windows and plot the results.

    Configure the bistatic transmitters. Use a pulse repetition frequencey of 1000 Hz.

    prf   = 1e3;
    wav   = phased.LinearFMWaveform(PRF=prf,PulseWidth=0.2/prf);
    ant   = phased.SincAntennaElement(Beamwidth=10);
    tx1   = bistaticTransmitter(Waveform=wav, ...
          Transmitter=phased.Transmitter(Gain=40), ...
          TransmitAntenna=phased.Radiator(Sensor=ant));
    tx2   = clone(tx1);
    prf   = 2e3;
    tx2.Waveform = phased.RectangularWaveform( ...
          PRF=prf,PulseWidth=0.2/prf);
    tx2.Transmitter.PeakPower = 2e3;

    Configure the bistatic receiver.

    rx    = bistaticReceiver( ...
          ReceiveAntenna=phased.Collector(Sensor=ant), ...
          WindowDuration=0.0025);
    freq  = tx1.TransmitAntenna.OperatingFrequency;

    Create bistatic transmitter platforms spaced 10 km apart. Put the receiver platform between the two transmitters. For this example, create the platforms in radarScenario. Define the platforms using platform.

    scene   = radarScenario(UpdateRate=prf);
    tx1Plat = platform(scene,Position=[-5e3 0 0], ...
            Orientation=rotz(85).');          
    tx2Plat = platform(scene,Position=[5e3 0 0], ...
            Orientation=rotz(95).');       
    rxPlat  = platform(scene,Position=[0 0 0], ...
            Orientation=rotz(90).');

    Place a stationary target platform down range and assign the target a radar cross section.

    rcsSig  = rcsSignature(Pattern=20); 
    tgtPlat = platform(scene,Position=[0 50e3 0], ...
            Signatures=rcsSig);

    Show platform locations and orientations.

    tp     = theaterPlot(Parent=axes(figure));
    txPltr = orientationPlotter(tp,Marker="^", ...
           DisplayName="TX",LocalAxesLength=1e3);
    rxPltr = orientationPlotter(tp,Marker="v", ...
           DisplayName="RX",LocalAxesLength=1e3);
    tgtPltr = orientationPlotter(tp,Marker="o", ...
            DisplayName="Target",LocalAxesLength=1e3);
    poses   = platformPoses(scene);
    plotOrientation(txPltr,[poses(1:2).Orientation], ...
    reshape([poses(1:2).Position],3,[]).',["TX1" "TX2"]);
    plotOrientation(rxPltr,poses(3).Orientation,poses(3).Position,"RX");
    plotOrientation(tgtPltr,poses(4).Orientation,poses(4).Position,"Target");

    Figure contains an axes object. The axes object with xlabel X (m), ylabel Y (m) contains 16 objects of type line, text. One or more of the lines displays its values using only markers These objects represent TX, x-TX, y-TX, z-TX, RX, x-RX, y-RX, z-RX, Target, x-Target, y-Target, z-Target.

    Transmit and collect pulses for four receive windows. First, update platform positions by calling advance on the scene. Then set up the for loop to iterate over the receive windows. Next, get platform positions using platformPoses. Get the propogation paths for both transmitters using bistaticFeeSpacePath. Then, transmit the signal and collect pulses. Finally, receive the transmissions and plot the received signals.

    tl    = tiledlayout(figure,2,1); 
    hAxes = [nexttile(tl) nexttile(tl)]; hold(hAxes,"on");
    tx    = {tx1 tx2};
    advance(scene);  
    for iRxWin = 0:4
        [propSigs,propInfo] = collect(rx,scene.SimulationTime);
        t    = min([nextTime(tx{1}) nextTime(tx{2})]);
        tEnd = nextTime(rx);
        while t <= tEnd  
            % Get platform positions
            poses = platformPoses(scene); 
    
            % Include target RCS signature on the pose
            tgtPose   = poses(4);
            tgtPose.Signatures = {rcsSig};
        
            for iTx = 1:2
                % Calculate propogation paths
                proppaths = bistaticFreeSpacePath(freq, ...
                          poses(iTx),poses(3),tgtPose);
    
                % Transmit
                [txSig,txInfo] = transmit(tx{iTx},proppaths,scene.SimulationTime);
    
                % Plot transmitted signal
                txTimes = (0:(size(txSig,1) - 1))*1/txInfo.SampleRate ...
                        + txInfo.StartTime;
                plot(hAxes(1),txTimes*1e3,mag2db(max(abs(txSig),[],2)),SeriesIndex=iTx);
               
                % Collect transmitted pulses
                collectSigs = collect(rx,txSig,txInfo,proppaths);
                
                % Accumulate collected transmissions
                sz = max([size(propSigs);size(collectSigs)],[],1);
                propSigs = paddata(propSigs,sz) + paddata(collectSigs,sz);
             end
                
             t = min([nextTime(tx{1}) nextTime(tx{2})]);
             advance(scene);
        end
            
            
        % Receive collected transmissions 
        [iq,rxInfo] = receive(rx,propSigs,propInfo);
    
        % Plot received transmissions
        rxTimes = (0:(size(iq,1) - 1))*1/rxInfo.SampleRate ...
                + rxInfo.StartTime;
        plot(hAxes(2),rxTimes*1e3,mag2db(abs(iq)));
    end

    Label plots.

    grid(hAxes,"on")
    title(hAxes(1),"Transmitter Signals")
    title(hAxes(2),"Receiver Signals")
    xlabel(hAxes,"Time (milliseconds)")
    ylabel(hAxes,"Power (dB)")
    ylim(hAxes(1),[0 80]); ylim(hAxes(2),[-130 -75])
    xlim(hAxes(1),xlim(hAxes(2)))

    Figure contains 2 axes objects. Axes object 1 with title Transmitter Signals, xlabel Time (milliseconds), ylabel Power (dB) contains 50 objects of type line. Axes object 2 with title Receiver Signals, xlabel Time (milliseconds), ylabel Power (dB) contains 4 objects of type line.

    Version History

    Introduced in R2025a