dbtex26.m

阵列信号处理的工具箱

function dbtex26

%DBTEX26 An example of simultaneous beamforming ad doppler filtering of radar signals.
%
%Description:
%  The filtering is performed with the function "spapulfilt". 
%  Both Capon and MUSIC methods are used. The needed correlation matrix
%  is estimated from from several CPIs, which are obtained by splitting
%  the number of pulses in a fewer number of pulses and several CPIs. As
%  comparison, separate conventional nonadaptive beamforming and doppler
%  filtering are calculated and displayed.
%  Two targets at the same range and with DOAs and Doppler frequencies
%  close to each other is simulated. A Barker 13 waveform is used and
%  pulse compression is performed before any processing in DOA or Doppler.
%
%See Also:
%  dbtex21, dbtex25

%
%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
%  (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%  Start        : 991101 Svante Bj鰎klund (svabj).
%  Latest change: $Date: 2000/10/16 15:39:48 $ $Author: svabj $.
%  $Revision: 1.4 $
%*****************************************************************************

% Script for simradarsig.!

%clear all

% ----------------------------------------------------------------------- %
% Definition of the antenna.
% ----------------------------------------------------------------------- %

lambda  = 0.03;             % wavelength.
D   = 0.45*lambda;          % Element separation.
noChannels   = 12;          % Number of digital antenna channels.
recAnt = defant('isotropULA',[noChannels,D]);


% ----------------------------------------------------------------------- %
% Definition of the waveform.
% ----------------------------------------------------------------------- %

pri = 1e-4;
noPulses = 1024;
noCPI = 1;
sampleTime = 1e-6;   % SubPulseLength [s]
noRangeBins = round(pri / sampleTime);
noRangeBins = 100;
pModulation = getmod('barker','13');  % Barker-13 has sidelobes 1/13 of the main peak.
%pModulation =[];
waveform = defwave(lambda, noRangeBins, noPulses, pModulation, sampleTime);


% ----------------------------------------------------------------------- %
% Definition of the sources.
% ----------------------------------------------------------------------- %

%target = deftarget(trgType, trgPower, trgRange, trgDOA, trgVel);
trg1 = deftarget('swerling0', 20, 1000, [d2r(25); 0], 20);
trg2 = deftarget('swerling0', 15, 1000, [d2r(24); 0], 18);
%trg3 = deftarget('swerling0', 12, 1000, [d2r(25); 0], 18);
%trg4 = deftarget('swerling0', 3, 1000, [d2r(24); 0], 20);
  % Targets at ranges 19 and 53 range bins.

%noiseSrc = defnoise(noiseType, noisePower);
noiseSrc1 = defnoise('Gaussian', 0.3, eye(noChannels));

%clutterdef = defclutter(clutterType, clutterTypeParam, clutterPower, clutterPatchDOAs, transAnt)
clutterSrc1 = defclutter('MIT-LCE', {6000 4 50}, 10, d2r(-30):0.01:d2r(30));

%srcDef = defsources(srcList, trgCorrMx)
sources = defsources({trg1 trg2 noiseSrc1}, eye(2));
%sources = defsources({trg1 trg2 trg3 trg4 noiseSrc1}, eye(4));
%sources = defsources({trg1 trg3 noiseSrc1 clutterSrc1}, eye(2));


% ----------------------------------------------------------------------- %
% Simulation of radar signals.
% ----------------------------------------------------------------------- %

radarSig1 = simradarsig(recAnt, sources, waveform, pri);
radarSig1 = sigsubix(radarSig1,':',1:25,':');
figure,sigplot2(radarSig1,':',':',1)
title('Radar signal before pulse compression.')
  % The amplitude will depend on the pulse number because the two targets will interfere with each other, sometimes constructively and simetimes destructively.


% ----------------------------------------------------------------------- %
% Signal processing and plotting.
% ----------------------------------------------------------------------- %

%----  Pulse compression ----

radarSig1=pulscomp(radarSig1,pModulation);

%ranAxis = (0:99)*150;
%ranAxis = (1:80)*150;
ranAxis = [];


%----  Split signal into several CPIs ----

figure,sigplot2(radarSig1,':',':',1)
title('Radar signal after pulse compression.')
radarSig2 = sigsubix(radarSig1,':',19,':');
radarSig2 = sigsplitdim(radarSig2, 1, 8, 5);


%----  Beamforming : Conv. beamf., without Doppler filt. ----

%spaAxis = d2r(-10:0.5:40);
spaAxis = [];

sigFinal = beamform(radarSig1,spaAxis,[],[],[]);
spaAxis = r2d(sigFinal.doaPos);


%----  Plotting the signal  ----
figure
sigplot2(sigFinal,1,':',':',{...
  'ranAxis', ranAxis, ...
  'spaAxis', spaAxis, ...
  'scaleType', 'lin'});
ylabel('Ranges [m]')
xlabel('Direction [degrees]')
title('Conventional beamforming')
%shading('interp')




%----  Doppler filtering : "dopplerfilt" , without beamforming ----
dopScaleType = 'lin';
noFreqsOut = noPulses;
prf = 1/pri;

pulAxis = genfreqaxis(0,prf,noFreqsOut).';

sigFinal2 = dopplerfilt(radarSig1, pulAxis);
spaAxis = r2d(sigFinal2.doaPos);
plotPulAxis = sigFinal2.freqPos * lambda / 2; % Radial speed.;

%----  Plotting the signal  ----
sigFinal2;
figure
sigplot2(sigFinal2,':',':',1,{...
  'spaAxis', spaAxis, ...
  'pulAxis', plotPulAxis, ...
  'scaleType', dopScaleType});
  %'ranAxis', ranAxis, ...
%ylabel('Doppler Frequency [Hz]')
ylabel('Radial speed [m/s]')
%xlabel('Direction [degrees]')
title('Doppler filtering with "dopplerfilt"')
%shading('interp')




%----  Beamforming and Doppler filtering : Conv. filt. ----
if (0)
%pulAxis = genfreqaxis(0,prf,noFreqsOut).';

sigFinal2 = spapulfilt(radarSig1, {
  'method', 'cbf',...
  'model', {radarSig1.antenna, radarSig1.waveform},...
  'sampleDim', 5});

spaAxis = r2d(sigFinal2.doaPos);
%plotPulAxis = sigFinal2.freqPos;
plotPulAxis = sigFinal2.freqPos * lambda / 2; % Radial speed.

%----  Plotting the signal  ----
figure
sigplot2(sigFinal2,':',19,':',{...
  'spaAxis', spaAxis, ...
  'pulAxis', plotPulAxis, ...
  'scaleType', dopScaleType});
  %'ranAxis', ranAxis, ...
%ylabel('Doppler Frequency [Hz]')
ylabel('Radial speed [m/s]')
%xlabel('Direction [degrees]')
title('Conv. space-pulse filtering, without beamforming')
%shading('interp')
end%if (0)


%----  Beamforming and Doppler filtering : Capon. ----

spaAxisIn = d2r(23.5:0.05:25.5);
pulAxisIn = (17.5:0.1:20.5)*2/lambda;


sigFinal2 = spapulfilt(radarSig2, {
  'method', 'capon',...
  'model', {radarSig2.antenna, radarSig2.waveform},...
  'doaFreqChoice', {spaAxisIn, pulAxisIn},...
  'sampleDim', 5});

spaAxis = r2d(sigFinal2.doaPos);
%plotPulAxis = sigFinal2.freqPos;
plotPulAxis = sigFinal2.freqPos * lambda / 2; % Radial speed.

%----  Plotting the signal  ----
figure
sigplot2(sigFinal2,':',1,':',{...
  'spaAxis', spaAxis, ...
  'pulAxis', plotPulAxis, ...
  'scaleType', dopScaleType});
  %'ranAxis', ranAxis, ...
%ylabel('Doppler Frequency [Hz]')
ylabel('Radial speed [m/s]')
xlabel('Direction [degrees]')
title('Capon space-pulse filtering, without beamforming')
%shading('interp')


%----  Beamforming and Doppler filtering : MUSIC. ----

spaAxisIn = d2r(23.5:0.05:25.5);
pulAxisIn = (17.5:0.1:20.5)*2/lambda;


sigFinal2 = spapulfilt(radarSig2, {
  'method', 'music',...
  'model', {radarSig2.antenna, radarSig2.waveform},...
  'doaFreqChoice', {spaAxisIn, pulAxisIn},...
  'sampleDim', 5});

spaAxis = r2d(sigFinal2.doaPos);
%plotPulAxis = sigFinal2.freqPos;
plotPulAxis = sigFinal2.freqPos * lambda / 2; % Radial speed.

%----  Plotting the signal  ----
figure
sigplot2(sigFinal2,':',1,':',{...
  'spaAxis', spaAxis, ...
  'pulAxis', plotPulAxis, ...
  'scaleType', dopScaleType});
  %'ranAxis', ranAxis, ...
%ylabel('Doppler Frequency [Hz]')
ylabel('Radial speed [m/s]')
xlabel('Direction [degrees]')
title('MUSIC space-pulse estimation, without beamforming')
%shading('interp')





%End Of File