ranstemat.m

阵列信号处理的工具箱

function A = ranstemat(waveform, ranges, propSpeed, interpMethod, storageClass, boundaryMethod)

%RANSTEMAT Calculation of range (fast time) steering matrix.
%
%--------
%Synopsis:
%  A = ranstemat(waveform, ranges)
%  A = ranstemat(waveform, ranges, propSpeed, interpMethod, storageClass, ...
%    boundaryMethod)
%
%Description:
%  Calculates the range (fast time) steering matrix for specified frequencies.
%
%  This function is normally not called by the end user but
%  by the extension programmer that extends the toolbox DBT with new signal
%  processing methods etc.
% 
%  The delivered range steering matrix is circular, i.e. if there is not
%  enough space for the puls modulation at the end of the range bins, it
%  will wrap around to the first range bin
%
%Output and Input:
%  A (CxMatrix): The calculated range (fast time) steering matrix. The size is 
%   (noRangeBins, noRanges), where noRangeBins is the number of range bins
%    and noRanges is the number of ranges. A "range bin" means ...
%    A "range" means ...
%  waveform (WaveformT): The waveform definition.
%  ranges (RealVectorT.'): Ranges to calculate the steering vectors at [m].
%  propSpeed [D](RealScalarT): Propagation speed of the waves [m/s].
%    Default = speed of light in free space.
%  interpMethod [D](StringT): Interpolation method to use between the
%    samples of the pulse modulation. See help text for function "interp1"
%    for possible methods.
%  storageClass [D](StringT): Specifies the MATLAB storage class for output
%    steering matrix "A".
%    = 'full': Use storage class "full".
%    = 'sparse': Use storage class "sparse". 
%  boundaryMethod [D](StringT): How to handle the boundaries of the PRI.
%    Not implemented.
%
%--------
%Notations:
%  Data type names are shown in parentheses and they start with a capital
%  letter and end with a capital T. Data type definitions can be found in [1]
%  or by "help dbtdata".
%  [D] = This parameter can be omitted and then a default value is used.
%  When the [D]-input parameter is not the last used in the call, it must be
%  given the value [], i.e. an empty matrix.
%  ... = There can be more parameters. They are explained under respective
%  metod or choice.
%
%Examples:
%
%Software Quality:
%  (About what is done to ascertain software quality. What tests are done.)
%
%
%Known Bugs:
%  When only a portion the ranges of a radar signal is retained (the
%  "ranIx" field of the data type "RxCorrMatT" contains a subset of all
%  possible range indices) this function can not handle it. Should it be
%  as with antenna definitions, with parent and children waveform and 
%  "beamforming"? This could maybe confuse doppler filtering since it
%  also use the waveform definition. Or should this function have extra
%  input parameters, e.g. "ranIx" and/or "trans.ranTrans",
%  "trans.sparanTrans", etc.?
%
%References:
%  [1]: Bj鰎klund S.: "DBT, A MATLAB Toolbox for Radar Signal Processing.
%    Reference Guide", FOA-D--9x-00xxx-408--SE, To be published.
%
%See Also:
%  ranfilt, spastemat, pulstemat

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Start        : 990222 Svante Bjvrklund (svabj).
%  Latest change: $Date: 2001/08/31 14:32:18 $ (17:08) $Author: svabj $.
%  $Revision: 1.7 $
% *****************************************************************************


% ----------------------------------------------------------------------- %
% Handle input parameters.
% ----------------------------------------------------------------------- %

% ****************** Add missing input parameters ******************

arginNo=2;
if (nargin < arginNo)
  error('DBT-Error: To few input parameters.')
end
arginNo = arginNo +1;

if (nargin < arginNo)
  propSpeed = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  interpMethod = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  storageClass = [];
end
arginNo = arginNo +1;


% ****************** Default values ******************

if isempty(propSpeed)
  propSpeed = speedoflight;
end%if
if isempty(interpMethod)
  interpMethod = '*nearest';
end%if
if isempty(storageClass)
  storageClass = 'full';
end%if


% ****************** Error check input parameters ******************

chkdtype(waveform, 'WaveformT')
%chkdtype(ranges, '???')
chkdtype(propSpeed, 'RealScalarT')
if (isempty(waveform.pModulation))
  error('DBT-Error: Empty pulse modulation.')
end%if


% ----------------------------------------------------------------------- %
% Perform the calculations.
% ----------------------------------------------------------------------- %
noRanges = length(ranges);
noRangeChan = waveform.noRangeBins;
pModulation = waveform.pModulation;
noPModCoeff = length(pModulation);
if (strcmp(storageClass,'full'))
  A  = zeros(noRangeChan,noRanges);
elseif (strcmp(storageClass,'sparse'))
  A  = spalloc(noRangeChan,noRanges, (noPModCoeff + 1) * noRanges);
else
  error('DBT-Error: Unknown storage class.')
end%if

%ranBinLen = (propSpeed * waveform.sampleTime)/2;
ranBinLen = getranbinlen(waveform, propSpeed);
  % Length in number of samples of the pulse modulation.
x = (-0.5:noPModCoeff-1 + 1.5).';
y = [0; pModulation; 0];


rangeInRangeBins = (ranges + ranBinLen) ./ ranBinLen;	
rangeBindDecimals = mod(rangeInRangeBins,1);
startRangeBin = fix(rangeInRangeBins);
endRangeBin = startRangeBin + noPModCoeff -1;


for rangeIx = 1:noRanges
  xi = (0:noPModCoeff-1).' + (rangeBindDecimals(rangeIx));
  pModInterp = interp1(x,y,xi,interpMethod);
  ARowIx = rem((startRangeBin(rangeIx):endRangeBin(rangeIx))-1,noRangeChan)+1;
  A(ARowIx,rangeIx) = pModInterp;
end%for rangeIx

%fprintf('ranstemat: issparse(A) = %d\n',issparse(A));



% ----------------------------------------------------------------------- %
% Remaining (not used).
% ----------------------------------------------------------------------- %

if (0)
%x = (-1:noPModCoeff-1 +1).'

%rangeInRangeBins = ranges ./ ranBinLen + 0.5;
  % If range bin 1 is centered around range = 150 m and so on.
%rangeBindDecimals = rem(rangeInRangeBins,1)
  % If range bin 1 is centered around range = 150 m and so on.
%startRangeBin = fix(rangeInRangeBins) 
  % If range bin 1 is centered around range = 150 m and so on.

%rangeInRangeBins = ranges ./ ranBinLen	

%rangeBindDecimals = mod(rangeInRangeBins + 0.5 ,1)

%startRangeBin = rem(fix(rangeInRangeBins) + 1 , noRangeChan)
%startRangeBin = rem(fix(rangeInRangeBins) , noRangeChan)

%xi = (0:noPModCoeff-1).'*(rangeBindDecimals - 0.5);
%xi = x(:);
%pModInterp = intrep1(x,y,xi,interpMethod);
%pModInterp = reshape(pModInterp,noPModCoeff,noRanges);
%A()=;

% for ...

  %xi = (0:noPModCoeff-1).'*((ranges(rangeIx) rem ranBinLen) - 0.5)
    % This is wrong!

  %xi = (0:noPModCoeff-1) + (rangeBindDecimals(rangeIx) - 0.5)
    % If range bin 1 is centered around range = 150 m and so on.

  %xi = (0:noPModCoeff-1) + (rangeBindDecimals(rangeIx) - 0.5)

  %pModInterp = interp1(x,y,xi(:,rangeIx),interpMethod)

  disp('Indices:')
  rangeIx
  size(A)

  %A(:,rangeIx) = [zeros(startRangeBin(rangeIx)-1,1); pModInterp; ...
  %  zeros(noRangeChan-endRangeBin(rangeIx),1)];
  %A(:,rangeIx) = [zeros(startRangeBin(rangeIx)-1,1), pModInterp(rangeIx), ...
  %  zeros(noRangeChan-endRangeBin(rangeIx),1)];

%end%for

end%if (0)