Demonstrates static attitude determination.

Look at random locations in the sky to test the star identification
algorithms.
------------------------------------------------------------------------
See also Mat2Q, Q2Mat, QPose, QRand, SaveStructure,
ComputePixelMapScale, PinholeStarCamera, QFromU, StarIdentification,
LoadCatalog, StarDataGeneration
------------------------------------------------------------------------

Script options
Star identification options
Camera parameters
Default FK5 catalog
Adjust intensity for the camera gain
Loop

%------------------------------------------------------------------------
%   Copyright (c) 2001 Princeton Satellite Systems, Inc.
%   All rights reserved.
%------------------------------------------------------------------------
%   Since version 5.5
%------------------------------------------------------------------------

Script options

%----------------
nSim           = 10;
plotStars      = true;
noiseOn        = false;

Star identification options

%----------------------------
options                      = struct;
options.useAbsoluteIntensity = true;
options.intensityTolerance   = 0.001;
options.useTriad             = true;

Camera parameters

%-------------------
pixels            = 256;
degToRad          = pi/180;
fieldOfView       = 30*degToRad;
camera            = PinholeCameraStruct( pixels, fieldOfView );
camera.gain       = 1e9;
camera.sigmaXY    = 0.1; % pixels
camera.noise      = noiseOn;
angularResolution = 0.1*fieldOfView/pixels;

Default FK5 catalog

%---------------------
catalogName        = 'ADSimStaticCatalog.mat';

% Create the catalog if it does not exist
% vM 4.2 will give 2 polar stars
%----------------------------------------
if( isempty(which(catalogName))  )
  starCatalog = LoadCatalog('Hipparcos',4.2);
  d           = StarDataGeneration( starCatalog, fieldOfView, angularResolution );
  SaveStructure( d, FileFullpath(catalogName) );
else
  d = load(catalogName);
end

d.pixelMapScale = camera.fScale;

Adjust intensity for the camera gain

%--------------------------------------
d.starMatrix(1,:) = d.starMatrix(1,:)*camera.gain;

Loop

%------
nGood  = 0;
nStars = 0;

for j = 1:nSim
	% Generate a random quaternion, create an image, and identify stars.

  fprintf(1,'\n-----------\nRun %i\n-----------\n',j);

  qECIToBody      = QRand;
  [rA, dec]       = Q2RADec( [0;0;1], qECIToBody );
  fprintf(1,'RA: %f Dec: %f\n',rA*180/pi,dec*180/pi);
  bBodyToCamera   = [0 0  1;0 1 0;-1 0 0];
  bECIToCamera    = bBodyToCamera*Q2Mat(qECIToBody);

  % Create measurements using a pinhole camera model
  starMeasurement = PinholeStarCamera( bECIToCamera, camera, d.starCatalog, plotStars );
  if (plotStars)
    str = get(gcf,'name');
    set(gcf,'name',['Run ' num2str(j) ': ' str]);
    drawnow
  end
  % Identify the stars
  [starID, uMeas, uCatalog] = StarIdentification( starMeasurement, d, options, plotStars );
  if (plotStars)
    pos = get(gcf,'position');
    str = get(gcf,'name');
    set(gcf,'position',[pos(1)+pos(3) pos(2:4)]);
    set(gcf,'name',['Run ' num2str(j) ': ' str]);
    drawnow
  end

  if( ~isempty(uMeas) )

    % Determine the attitude
    %-----------------------
    starID
    [qMeas, bMeas] = QFromU( uMeas, uCatalog );
    qECIToBodyMeas = Mat2Q( (bMeas*bBodyToCamera));

    if( ~isempty(qMeas) )
	    nGood  = nGood + 1;
      nStars = nStars + length(starID);
      fprintf(1,'qTrue     = [%8.4f %8.4f %8.4f %8.4f]\nqEstimate = [%8.4f %8.4f %8.4f %8.4f]\nerror = %12.4e\n',...
          qECIToBody,QPose(qECIToBodyMeas),norm(qECIToBody-QPose(qECIToBodyMeas)));
    else
      fprintf(1,'qTrue = [%8.4f %8.4f %8.4f %8.4f] No estimate possible.\n',qECIToBody);
    end
  end
end

if( nGood > 0 )
  fprintf(1,'\n%i out of %i tests produced a valid attitude using an average of %i stars\n',...
      nGood,nSim,floor(nStars/nGood));
end


%--------------------------------------
% PSS internal file version information
%--------------------------------------

-----------
Run 1
-----------
RA: 72.955595 Dec: 17.942173
Table of Star Names
-------------------
Number Name
   594 
   596 
   642 
   643 
   652 IOT Cy
   658 
   664 
   681 
   682 
   683 
   692 
   698 Dene
   700 
   710 
   715 Alderami
   716 
   720 
   721 
   731 
   736 
   743 
   753 
starID =
  Columns 1 through 13
   594   596   642   643   652   658   664   681   682   683   692   698   700
  Columns 14 through 22
   710   715   716   720   721   731   736   743   753
qTrue     = [  0.5383   0.2457  -0.5344  -0.6035]
qEstimate = [  0.5383   0.2457  -0.5344  -0.6035]
error =   5.6132e-16

-----------
Run 2
-----------
RA: 51.963516 Dec: -33.158233
Table of Star Names
-------------------
Number Name
   267 
   275 
   276 
   279 
   281 
   298 
   304 Alphar
   310 
   311 
   312 
   323 Regulu
   332 
starID =
   267   275   276   279   281   298   304   310   311   312   323   332
qTrue     = [  0.4503   0.8308  -0.2884   0.1541]
qEstimate = [  0.4503   0.8308  -0.2884   0.1541]
error =   5.2369e-16

-----------
Run 3
-----------
RA: 42.687506 Dec: -54.574573
Table of Star Names
-------------------
Number Name
   161 
   166 
   173 
   177 
   181 
   182 
   184 
   188 
   191 
   193 
   195 
   198 GAM Ge
   202 
   203 
   205 
   210 
   215 
   225 
   226 
   229 
   231 
   245 
   247 Pollu
starID =
  Columns 1 through 13
   161   166   173   177   181   182   184   188   191   193   195   198   202
  Columns 14 through 23
   203   205   210   215   225   226   229   231   245   247
qTrue     = [  0.3038   0.6822  -0.6649   0.0162]
qEstimate = [  0.3038   0.6822  -0.6649   0.0162]
error =   5.6899e-16

-----------
Run 4
-----------
RA: 131.905939 Dec: -29.360649
Table of Star Names
-------------------
Number Name
   494 
   536 
   539 
   551 
   553 
   554 
   555 
   556 
   557 
   558 
   560 
   564 
   570 
   571 
   573 
   574 
   576 
   577 Shaul
   579 
   585 
   587 
   589 
   592 
   593 
   604 
   616 
   620 
   635 
starID =
  Columns 1 through 13
   494   536   539   551   553   554   555   556   557   558   560   564   570
  Columns 14 through 26
   571   573   574   576   577   579   585   587   589   592   593   604   616
  Columns 27 through 28
   620   635
qTrue     = [  0.5003   0.5595   0.6574   0.0676]
qEstimate = [  0.5003   0.5595   0.6574   0.0676]
error =   3.6428e-16

-----------
Run 5
-----------
RA: -133.839722 Dec: -11.607799
Table of Star Names
-------------------
Number Name
   562 
   568 
   594 
   596 
   612 
   623 
   631 
   642 
   643 
   652 IOT Cy
   658 
   664 
   700 
   715 Alderami
   716 
   720 
   721 
starID =
  Columns 1 through 13
   562   568   594   596   612   623   631   642   643   652   658   664   700
  Columns 14 through 17
   715   716   720   721
qTrue     = [  0.1260  -0.6374  -0.4408   0.6193]
qEstimate = [  0.1260  -0.6374  -0.4408   0.6193]
error =   4.9728e-16

-----------
Run 6
-----------
RA: -22.718027 Dec: 5.641214
Table of Star Names
-------------------
Number Name
    70 TET02 Er
    77 
    79 
    83 
    97 
   109 
   111 
   115 d Er
   119 
   121 
   125 
   134 
   147 
starID =
    70    77    79    83    97   109   111   115   119   121   125   134   147
qTrue     = [  0.2104   0.5202  -0.4245   0.7105]
qEstimate = [  0.2104   0.5202  -0.4245   0.7105]
error =   4.2276e-16

-----------
Run 7
-----------
RA: -84.184298 Dec: -33.703217
Table of Star Names
-------------------
Number Name
   495 
   532 
   535 
   547 
   550 
   562 
   572 
   584 
   594 
   596 
   597 GAM Dr
   605 
starID =
   495   532   535   547   550   562   572   584   594   596   597   605
qTrue     = [  0.3932  -0.6817  -0.5593   0.2607]
qEstimate = [  0.3932  -0.6817  -0.5593   0.2607]
error =   2.0015e-16

-----------
Run 8
-----------
RA: -175.663306 Dec: -20.496385
Table of Star Names
-------------------
Number Name
   109 
   111 
   115 d Er
   119 
   120 
   121 
   125 
   147 
   154 
   163 
   168 
   171 
   178 
   186 
starID =
  Columns 1 through 13
   109   111   115   119   120   121   125   147   154   163   168   171   178
  Column 14
   186
qTrue     = [  0.5363  -0.3362   0.7497   0.1932]
qEstimate = [  0.5363  -0.3362   0.7497   0.1932]
error =   6.1125e-16

-----------
Run 9
-----------
RA: 19.728100 Dec: -12.491299
Table of Star Names
-------------------
Number Name
   190 
   196 
   197 
   201 
   204 Siriu
   211 
   212 Adhara
   213 
   214 
   216 
   217 
   219 
   224 
   228 
   236 
   239 
   242 
   244 
   248 
   250 
   252 
   256 
   257 
starID =
  Columns 1 through 13
   190   196   197   201   204   211   212   213   214   216   217   219   224
  Columns 14 through 23
   228   236   239   242   244   248   250   252   256   257
qTrue     = [  0.4571   0.6938  -0.3561   0.4277]
qEstimate = [  0.4571   0.6938  -0.3561   0.4277]
error =   9.0024e-16

-----------
Run 10
-----------
RA: -71.187650 Dec: 62.764387
Table of Star Names
-------------------
Number Name
   569 
   573 
   577 Shaul
   582 
   585 
   589 
   591 
   592 
   593 
   602 GAM Sg
   606 
   609 
   610 
   611 
   615 Kaus Australi
   617 
   618 
   624 
   629 SIG Sg
   632 
   634 
   637 
   640 
   641 
   644 
   646 
starID =
  Columns 1 through 13
   569   573   577   582   585   589   591   592   593   602   606   609   610
  Columns 14 through 26
   611   615   617   618   624   629   632   634   637   640   641   644   646
qTrue     = [  0.6455  -0.2048   0.1162  -0.7265]
qEstimate = [  0.6455  -0.2048   0.1162  -0.7265]
error =   5.4177e-16

10 out of 10 tests produced a valid attitude using an average of 19 stars

Demonstrates static attitude determination.

Contents

Script options

Star identification options

Camera parameters

Default FK5 catalog

Adjust intensity for the camera gain

Loop