ranfilt.m

阵列信号处理的工具箱

function [sigOut, basisMat, rangePosOut] = ranfilt(sigIn, method, model, modelParam, rangeChoice, taperCoeff, interCorrMat, steVecFlag, extraParam, orthBeamFlag)

%RANFILT Range linear filtering (i.e. pulse compression).
%
%--------
%Synopsis:
%  sigOut = ranfilt(sigIn)
%
%  [sigOut, basisMat, rangePosOut] = ranfilt(sigIn, method,
%    {antenna, waveform}, {propSpeed, interpMethod, storageClass, ...
%    boundaryMethod}, rangeChoice, taperCoeff, interCorrMat, steVecFlag, ...
%    extraParam, orthBeamFlag)
%
%  [sigOut, basisMat, rangePosOut] = ranfilt(sigIn, keywordList)
%
%Description:
%  Range linear filtering (i.e. pulse compression).
%
%  This function works like beamforming functions in the way that range 
%  steering vectors are created which then are correlated with the input
%  signal. The range of the steering vectors are specified by the input 
%  parameter "rangeChoice". It is not necessary that the ranges span all
%  ranges in the input signal or are multiples of one range bin.
%  This function calls the general functions "calcfiltinit" and "calcfiltproc" 
%  for the actual processing. This means that the methods implemented in
%  these functions can be tried but it is not sure that they are all are 
%  applicable for range filtering (this function). See also below about
%  the input parameter "method".
%
%  After the execution of this function, targets in range bin 1 is located
%  in element number 1 in the output signal matrix. This is different from 
%  the old function "pulscomp".
%
%  This function can be very memory consuming, especially if there are
%  many range bins in the input signal. This function can require long 
%  execution time, especially if many ranges are specified with the input 
%  parameter "rangeChoice".
%
%Output and Input:
%  sigOut (RxRadarSigT): Output radar signal.
%  basisMat ():
%  rangePosOut (RealVectorT.'): The tested ranges [m].
%
%  sigIn (RxRadarSigT): Input radar signal.
%
%  keywordList [D](CellArrayT): A cell array with input parameter name
%    (keyword) and value pairs, see the example below. All input parameters
%    of this function following "sigIn" can be used. The use of keywords
%    is to simplify calls to this function with many input parameters.
%
%  method (StringT): Filter method. See help text of function "calcfiltinit"
%    for sections about each method.
%    = 'conv': Non-adaptive pulse compression in the range domain (convolution).
%      This is tested and works.
%    = 'aconv': Adaptive pulse compression in the range domain (convolution). 
%      This is pulse compression with adaptive sidelobe cancelation (ASLC).
%      A range interference correlation matrix should be specified with the 
%      "interCorrMat" input parameter. In this way disturbing signals at some 
%      ranges should be suppressed. Not tested for range filtering.
%    = 'capon': Capon's method. Unsure if this works for range filtering. 
%      See for example "dbtex22".
%    = 'fft': Discrete fourier transform. Cannot be used with this function.
%    = 'ifft': Inverse discrete fourier transform. Cannot be used with this 
%      function.
%    = 'music : MUSIC. Not tested for range filtering.
%  antenna [D](AntDefT): Antenna model to use. If this parameters is an
%    empty matrix, the antenna model in the input signal "sigIn" is used
%    instead.
%  waveform [D](WaveformT): Waveform (time properties) model to use. 
%    If this parameters is an empty matrix, the waveform model in the input
%    signal "sigIn" is used instead.
%  propSpeed [D](RealScalarT): Propagation speed of the waves [m/s].
%    Default = speed of light in free space.
%  interpMethod [D](StringT): Interpolation method to use when calculating
%    the range steering matrices. See function "ranstemat" for possible
%    methods.
%  storageClass [D](StringT): Specifies the MATLAB storage class for range
%    steering matrices. See function "ranstemat" for more information.
%  boundaryMethod [D](StringT): How to handle the boundaries of the PRI.
%    See function "ranstemat" for more information.
%  rangeChoice [D](RealVectorT.'): One or more ranges to test [m].
%  taperCoeff [D](CxVectorT): Tapering coefficients to use.
%  interCorrMat [D](CxMatrixT): Interference signal correlation matrix. 
%    This is used to adaptively suppress the interference.
%  steVecFlag [D](BoolT): Specifies whether the steering vector (= 1, default) 
%    or filter weights (= 0) will be used in the filtering.
%  extraParam [D](): The use and data type depend on filter method. See help 
%    text of function "calcfiltinit" for sections about each method.
%  orthBeamFlag [D](BoolT): 1 = orthogonalize the weight vectors. 
%    0 = Do not do it (default).
%
%--------
%Conventional Pulse Compression.
%Synopsis:
%
%Output and Input:
%
%Description:
%
%Algoritm:
%
%--------
%Conventional Pulse Compression.
%Synopsis:
%
%Output and Input:
%
%Description:
%
%Algoritm:
%
%--------
%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.)
%  Only the method 'conv' ist tested and found to work. See for example 
%  "dbtex22".
%
%Known Bugs:
%  *) When using methods , e.g. 'capon' or 'music', requiring a correlation 
%  matrix, this matrix is currently estimated using the pulses.
%  If the number of range bins is larger than the number of pulses, 
%  which often is the case, the correlation matrix will be singular and
%  cannot be used. 
%  Consequently these methods will not work in these cases. Warning messages
%  like the following will appear:
%    Warning: Matrix is close to singular or badly scaled.
%        Results may be inaccurate. RCOND = 1.599693e-20.
%
%  *) This function do not use the function "calcfiltsig".
%
%  *) If the waveform parameter "pModulation" is not specified for radar 
%  measurements this function will not work. See the function "expsig1"
%  for more information.
%
%  *) For Capon, only the non-adapted steering matrix is stored. See the 
%  function "calcfiltinit".
%
%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:
%  calcfiltinit, pulsecomp, pulscomp, pulfilt, spafilt

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Start        : 990301 Svante Bj鰎klund (svabj).
%  Latest change: $Date: 2001/08/31 14:34:16 $ $Author: svabj $.
%  $Revision: 1.11 $
% *****************************************************************************

%Child functions for "ranfilt" rev. 1.9:
%  calcfiltproc 
%  ranstemat 
%  getm3 
%  dbtinfo 
%  chkdtype 
%  calcfiltinit 
%  setrantrans 
%  getranbinlen 
%  sigsize 
%  speedoflight 
%  iscell 


% The comment "NFF" stands for "New filter function" and gives tips to
% necessary changes when using this function as a template for new filter 
% functions (in other dimensions).

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

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

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

if (nargin < arginNo)
  method = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  model = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  modelParam = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  rangeChoice = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  taperCoeff = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  interCorrMat = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  steVecFlag = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  extraParam = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  orthBeamFlag = [];
end
arginNo = arginNo +1;


% *************** Evalute the list of keywords  ***************
% If the input parameter "method" is a cell array, it is interpreted as a
% list of input parameter name (keyword) and value pairs.
% The values of these keywords are assigned to the local variables with
% the same name as the keywords. The use of keywords is to make calls to
% this function simpler.

if (iscell(method))
  keywordList = method;
  lenExtra = length(keywordList);
  if (mod(lenExtra,2) ~= 0), error('DBT-Error: Keyword value missing.'),end%if
  for n = 1:2:length(keywordList)
    eval([keywordList{n} '= keywordList{n+1};' ]);
  end%for n
end
arginNo = arginNo +1;