dbf.m

阵列信号处理的工具箱

function sigOut = dbf(sig, beamPos, theta0, taperType, taperParam)

% *****************************************************************************
%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  function sigOut = dbf(sig, beamPos, theta0, taperType, taperParam)
%
%  Digital beamformer. Calculates the signals in beams specified by beamPos.
%
%  sigOut (RxRadarSigT):
%  sig (RxRadarSigT):
%  beamPos (Vector of DoaT)(= RealMatrixT 2 x M) : Directions of the
%    beams to calculate
%  theta0 (RealScalarT): Subarray pointing direction.
%  taperType [D], taperParam [D]: Defines the tapering to use. See the function
%    "gettap1" for more information.
%
%Known Bugs:
%  dbf does not add a new level of the antenna definition with a new
%  beamSpaceTrans field. This means that no DOA estimation is possible
%  after execution of dbf.
%
%  It is unclear if the tapering works correctly.


%  Start        : 961120 Fredrik Athley (freath).
%  Latest change: $Date: 2000/10/16 15:20:20 $ $Author: svabj $.
%  $Revision: 1.25 $
% *****************************************************************************

ant = sig.antenna;

%lambda  = ant.lambda;
waveform = sig.waveform;
lambda   = waveform.wavelength;
noWavelengths = length(lambda);

noElem = ant.noElem;
XX =  sig.signals;
s = sizem(XX);

noPulses    = s(1);
noRangeBins = s(2);
noChannels  = s(3);
noNotUsed   = s(4);
noCPIs      = s(5);
noTrials    = s(6);

if size(beamPos,1)==1
  beamPosAz = beamPos;
else
  beamPosAz = beamPos(1,:);
  beamPosEl = beamPos(2,:);
end
noBeams = length(beamPosAz);
YY = zerosm([s(1:2) noBeams s(4:6)]);
if nargin<3
  theta0 = (beamPosAz(1) + beamPosAz(noBeams))/2;
end
% ----------------------------------------------------------------------- %
% Tapering.
%
% ----------------------------------------------------------------------- %
if nargin<4
  %taperType='taylor';
  taperType='uniform';
end
if nargin<5
  taperParam = 40;
end

if (0)
  % The code in this alternative should be removed.
if (strcmp(taperType,'notaper'))
  taper = ones(noElem,1);
elseif (strcmp(taperType,'taylor'))
  SLL = taperParam;
  nbar = 12;
  taper = tayltap(SLL,nbar,noElem)';
    % Should it not be .' instead of ' ?
else
  error('DBT-Error: Desired taper type not implemented.')
end
else
  %taperType
  %taperParam
  taper = gettap1(ant,taperType,taperParam);
end%if (0)

taperMatrix = sparse(diag(taper));

if (noWavelengths == 1)
  W = spastemat(ant,beamPosAz,lambda,Inf,theta0);
  W = full(taperMatrix*W);
end%if

for trialLoop = 1:noTrials
for cpi=1:noCPIs
  if (noWavelengths > 1)
    W = spastemat(ant,beamPosAz,lambda(cpi),Inf,theta0);
    W = full(taperMatrix*W);
  end%if
  for notUsedLoop = 1:noNotUsed
  for range=1:noRangeBins
    %fprintf('range = %d, cpi = %d\n',range, cpi)
    X = getm(XX,':',range,':',notUsedLoop,cpi,trialLoop);
    [r,c] = size(X);
    if r~=noChannels
      X = X.';
    end
    %Y = W.'*X;
    Y = W'*X;
    %YY = setm(YY,Y.',':',range,':',notUsedLoop,cpi,trialLoop);
    YY(':',range,':',notUsedLoop,cpi,trialLoop) = Y.';	% setm
      % Test of change to Matlab 5 indexing instead of setm:
      %  >> all(all(all((sig2.signals == sig20.signals),1),2),3)
      %   ans =
      %         1
  end%for range
  end%for notUsedLoop
  infoStr = sprintf('dbf: cpi = %d(%d), range = %d(%d)\r',cpi, noCPIs, ...
    range,noRangeBins);
  dbtinfo(infoStr,1);
end%for cpi
dbtinfo('');	%New line.
end%for trialLoop

%sigOut.dataType = 'RxRadarSigT';
sigOut = sig;
sigOut.antenna = ant;
sigOut.signals = YY;