simradarsig.m

阵列信号处理的工具箱

function radarSigS = simradarsig(recAnt, sources, waveform, pri, propSpeed, modelParam, pulIx, ranIx, spaIx, extraIx, cpiIx, trialIx)

%SIMRADARSIG simulates radar signals from targets, noise and clutter.
%
%Synopsis:
%  radarSigS = simradarsig(recAnt, sources, waveform, pri, propSpeed,
%    {subArrPoint, focusDist})
%
%Description:
%  Simulates radarsignals and stores the data in a 3D matrix
%  ( Number Pulses x Number Of RangeBins x Number Of Channels)
%  Radarsignal simulation is devided into (so far) three different parts,
%  noise simulation, target simulation and clutter simulation. The tasks
%  to simulated these contributions are performed in separate functions
%  such as "simnoise.m", "simtarget.m" and "simclutter.m". These functions
%  are called one time for each coherent pulse interval (CPI). Alternation
%  of wavelengths between cpi:s are supported, see function "defwave.m"
%  for more information. The simulated data is then arranged in a
%  structure variable of the type "RxRadarSigT". All targets are seen as
%  stationary in that respect that they does not move from rangebin to
%  rangebin nor move in direction between CPIs. The velocity of the
%  targets are used to determine the phaseshifts between pulses and
%  subpulses (rangebins).
%
%  For the noise simulation, the antenna definition "recAnt" is not used.
%  See help text of function "simnoise" for more information on the noise
%  simulation.
%
%Input:
%  recAnt (AntDefT)         : Definition of the receiving antenna.
%  sources (SourceDefT)     : Structure variable with the signal sources
%     to be simulated, i.e. targets, noise or clutter (so far).
%  waveform (WaveformT)     : Waveform of the transmitted radarsignal.
%  pri (RealScalarT)        : Pulse repetition Intervall. [s] This quantity
%    is used when calculating phase shift (or doppler frequency) due to
%    radial velocity. The field "noRangeBins" in the input parameter
%    "waveform" determines the number of range bins to simulate.
%  propSpeed [D](RealScalarT):Propagation speed of the radar wave [m/s].
%                             Default is speed of light in empty space.
%  subArrPoint [D](DoaT)    : Pointing direction of subarrays.
%  focusDist [D](RealVectorT):Focusing distance of the antenna [m].
%  pulIx [D](IndexT): Pulse or doppler channel numbers to simulate.
%    Not implemented.
%  ranIx [D](IndexT): Range bins (numbers) to simulate.
%    Not implemented.
%  spaIx [D](IndexT): Spatial channel numbers to simulate.
%    Not implemented.
%
%OutPut:
%  radarSigS (RxRadarSigT)  : Struct with the simulated radarsignal.
%                             pulses x rangebins x channels.
%
%--------
%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".
%
%Examples:
%  trg1 = deftarget('swerling0', 1.2, 6000, [d2r(25); 0], 2);
%  trg2 = deftarget('swerling0', 0.6, 1000, [d2r(18); 0], -2);
%  trg3 = deftarget('swerling0', 0.8, 730000, [d2r(-3); 0], 0);
%
%  noiseSrc1 = defnoise('Gaussian', 0.3, eye(noChannels));
%
%  clSrc1 = defclutter('MIT-LCE', {6000 4 50}, 1, d2r(-30):0.01:d2r(30));
%
%  sources = defsources({trg1 trg2 trg3 noiseSrc1 clutterSrc1}, eye(3));
%
%  pMod = getmod('barker','13');
%  waveform = defwave(wavelength, noRangeBins, noPulses, pMod, sampleTime)
%
%  radarSig = simradarsig(recAnt, sources, waveform, pri);
%
%     First there is some definitions of sources, three targets one noise
%     and one clutter source. Then these sources are combined together in
%     a new structure variable that arranges data in such a way that
%     simulation is less time consuming. A waveform is defined and finally
%     radar data is simulated, using the function "simradarsig".
%
%Software Quality:
%
%Known Bugs:
%
%References:
%  [1]: Bj鰎klund S., Rejdemyhr D. Athley F.: "DBT, A MATLAB Toolbox
%       for Radar Signal Processing. Reference Guide",
%       FOA-D--9x-00xxx-408--SE, To be published.
%  [2]: Kingsley S., Quegan S.: "Understanding Radar Systems",
%       McGraw-Hill 1992.
%  [3]: Nordling C., Osterman J., Physics Handbook for Science and
%       Engineering, Studentlitteratur 91-44-16575-7.
%
%See also:
%  deftarget, defnoise, defclutter, defjammer, simtarget, simnoise,
%  simclutter, simjammer, defwave, getmod, dbtex20

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
%  (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Initiation    : 980511 David Rejdemyhr (davrej).
%  Latest change : $Date: 2000/10/16 15:21:55 $ $Author: svabj $.
%  $Revision     : 1.0 $
%*************************************************************************


  if (nargin < 4)
    error('DBT-Error: To few input parameters.')
  end

% -----------------------------------------------------------------------
%----                 Add missing input parameters                   ----
% -----------------------------------------------------------------------

  arginNo=5;
  if (nargin < arginNo)
    propSpeed = [];
  end
  arginNo = arginNo +1;
  if (nargin < arginNo)
    modelParam = [];
  end
  arginNo = arginNo +1;
  if (nargin < arginNo)
    pulIx = [];
  end
  arginNo = arginNo +1;
  if (nargin < arginNo)
    ranIx = [];
  end
  arginNo = arginNo +1;
  if (nargin < arginNo)
    spaIx = [];
  end
  arginNo = arginNo +1;


%-------------------------------------------------------------------------
%----                    Handle default values.                       ----
%-------------------------------------------------------------------------

  if (isempty(propSpeed))
    %propSpeed = 299792458;
    propSpeed = speedoflight;
  end%if

  if isempty(modelParam)
    modelParam = {[] []};
  end%if
  subArrPoint = modelParam{1};
  focusDist = modelParam{2};
  if isempty(subArrPoint)
    subArrPoint = [0 0].';
  end%if
  if isempty(pulIx)
    pulIx = [];
  end%if
  if isempty(ranIx)
    ranIx = [];
  end%if
  if isempty(spaIx)
    spaIx = [];
  end%if


%-------------------------------------------------------------------------
%----            Pick out fields from input parameters.               ----
%-------------------------------------------------------------------------

  noCPI       = waveform.noCPI;
  wavelength  = waveform.wavelength;
  noRangeBins = waveform.noRangeBins;
  noPulses    = waveform.noPulses;
  pMod        = waveform.pModulation;
  sampleTime  = waveform.sampleTime;

%-------------------------------------------------------------------------
%----                       Simulate radarsignal.                     ----
%-------------------------------------------------------------------------

  noChannels = recAnt.noElem;
  radarSig = zeros(noPulses, noRangeBins, noChannels,1, noCPI);

  for cpiIdx = 1:noCPI
     infoStr = sprintf('Cpi=%d: ',cpiIdx);
     dbtinfo(infoStr, 1);

    %----  Alternating wavelengths between cpi:s  ----
    if length(wavelength) > 1,
      lambda = wavelength(cpiIdx);
    else
      lambda = wavelength;
    end%if


    %---------------------------------------------------------------------
    %----                 Simulation of Targets                       ----
    %---------------------------------------------------------------------

    if isfield(sources,'Targets')

      targetPowers = sources.Targets.Powers;
      targetSpeeds = sources.Targets.Velocities;
      targetTypes  = sources.Targets.Types;
      targetRanges = sources.Targets.Ranges;
      targetDOAs = sources.Targets.DOAs(1,:); % Only theta angles so far
      targetStartPhases = rem(targetRanges,lambda)/lambda*2*pi;
      if isfield(sources.Targets,'CorrMx')
        targCorrMx = sources.Targets.CorrMx;
      else
        targCorrMx = [];
      end %if

      tic
      steeringMatrixTarg = spastemat(recAnt, targetDOAs(1,:), lambda, ...
        focusDist, subArrPoint);

      infoStr = sprintf('simradarsig: Simulating targets...');
      dbtinfo(infoStr, 1);
      radarSig3DTarg = simtarget(steeringMatrixTarg, pri, lambda, pMod,...
                               sampleTime, targetPowers, targetSpeeds, ...
                               targetRanges, targetTypes, ...
                               targetStartPhases, noPulses, ...
                               noRangeBins, targCorrMx, propSpeed);
      timeItTook = toc;
      infoStr = sprintf(' done (%2.1f secs).', timeItTook);
      dbtinfo(infoStr,[],1);
    else
%      dbtinfo('simradarsig: No targets present');
      radarSig3DTarg = 0;
    end %if


    %---------------------------------------------------------------------
    %----                   Simulation of Noise                       ----
    %---------------------------------------------------------------------

    if isfield(sources,'NoiseSources')
      dbtinfo('simradarsig: Simulating noise...', 1);
      tic
      radarSig3DNoise = simnoise(sources.NoiseSources, noPulses, ...
                                noRangeBins, noChannels);
      timeItTook = toc;
      infoStr = sprintf(' done (%2.1f secs).', timeItTook);
      dbtinfo(infoStr,[],1);
    else
%      dbtinfo('simradarsig: No noise present');
      radarSig3DNoise = 0;
    end %if


    %---------------------------------------------------------------------
    %----                 Simulation of Clutter                       ----
    %---------------------------------------------------------------------

    if isfield(sources,'Clutter')
      tic
      dbtinfo('simradarsig: Simulating clutter...', 1);
      if strcmp(sources.Clutter.TransAnt, 'recAnt')
        sources.Clutter.TransAnt = recAnt;
      end%if
      platHeight = sources.Clutter.PlatHeight;
      platVel = sources.Clutter.PlatVelocity;

      spec = pantpat3(sources.Clutter.TransAnt, [], [], [], [], [], [],...
                      sources.Clutter.DOAs, lambda, [], [], [], [], [],...
                      'noplot'); %Main Direction of Transmitting antenna is theta = 0;

      transmitGain = spec.specSmpl;

      steeringMatrixClutter = spastemat(recAnt, sources.Clutter.DOAs,lambda,...
        focusDist, subArrPoint); %Receiving antenna

      radarSig3DClutter = simclutter(sources.Clutter, transmitGain, ...
                                     steeringMatrixClutter, lambda, ...
                                     sampleTime, noPulses, noRangeBins,...
                                     propSpeed, pri, platHeight, platVel);
      timeItTook = toc;
      infoStr = sprintf(' done (%2.1f secs).', timeItTook);
      dbtinfo(infoStr,[],1);
    else
%      dbtinfo('simradarsig: No clutter present');
      radarSig3DClutter = 0;
    end %if


    %---------------------------------------------------------------------
    %---- Combine all simulated signals into a complete radar signal. ----
    %---------------------------------------------------------------------

    radarSig3D = radarSig3DTarg + radarSig3DNoise + radarSig3DClutter;

    radarSig(:,:,:,1,cpiIdx) = radarSig3D;

  end %for

%-------------------------------------------------------------------------
%----             Complete the struct & deliver the result.           ----
%-------------------------------------------------------------------------
  radarSigS = RxRadarSigT(radarSig, {recAnt, waveform});
    % Store also "pulIx", "ranIx", "spaIx"?!

%End Of File -------------------------------------------------------------