Demonstrates how to use the thermal modeling package

The spacecraft is a cube with two solar wings. ------------------------------------------------------------------------ See also SpaceCamera, SpaceThermalCamera, SpacecraftThermal, PlotThermal, DrawSCPlanPlugIn, QForm, QLVLH, QPose, TimeGUI, FindSolsticeOrEquinox, RVFromKepler, SolarFlx, SunV1, AutoPoint, CameraDatabase, ThermalImager ------------------------------------------------------------------------

Contents

%-------------------------------------------------------------------------------
%   Copyright (c) 1998-2003, 2007 Princeton Satellite Systems, Inc.
%   All rights reserved.
%-------------------------------------------------------------------------------

Load the CAD model

%-------------------
g = load('SCForImaging');
DrawSCPlanPlugIn(g);

% Initial rotation of solar arrays
%---------------------------------
g.body(2).bHinge.angle = 0;
g.body(2).bHinge.axis  = 2;
g.body(3).bHinge.angle = 0;
g.body(3).bHinge.axis  = 2;

Set up the simulation

%-----------------------
global simulationAction
simulationAction = 'Do Nothing';

% Ephemeris
%----------
jD0   = FindSolsticeOrEquinox('spring equinox',2002);
nDays = 2;
nSamp = 300;
t     = linspace(0,nDays,nSamp)*86400;
jD    = jD0 + t/86400;
dTSim = t(2)-t(1);

% Spacecraft orbit (GEO)
%-----------------------
[rECI, vECI] = RVFromKepler( [42167 0 0 0 0 0], t );

% Camera
%-------
camera                  = CameraDatabase('256 square');
camera.up               = [0;-1;0];
camera.focalLength      = 0.05;

% Initialize the picture in SpaceCamera
%--------------------------------------
% The optical camera
qECIToLVLH              = QLVLH( rECI(:,1), vECI(:,1) );
g.body(1).bHinge.q      = QPose(qECIToLVLH);
g.rECI                  = rECI(:,1);
g.qLVLH                 = qECIToLVLH;
g.name                  = 'Satellite';
d                       = struct('position',[]);
d.planetName            = 'Earth';
d.camera                = camera;
tagVisibleCameraWindow  = SpaceCamera( 'initialize', d, g, jD(1) );

% The thermal camera
%-------------------
figH = findobj( 'tag', tagVisibleCameraWindow );
h    = get( figH, 'UserData' );
d.position              = get(h.fig3D,'position') + [camera.xPixels 0 0 0];
d.planetName            = 'Earth';
d.camera                = camera;
d.imagerFunction        = @ThermalImager;
d.colorMap              = hot;
d.tempMax               = 700;
g.temperature           = 300*ones(length(g.component),1);
d.name                  = 'SpaceThermalCamera';
tagInfraredCameraWindow = SpaceCamera( 'initialize', d, g, jD(1) );

% Environment data for thermal temperature model
%-----------------------------------------------
e = struct;
flux0                   = SolarFlx(1);
e.planet                = 'earth';
e.planetRadius          = 6378.165;
e.s                     = flux0*SunV1(jD(1)); % Watts/m^2
e.tSamp                 = dTSim;
e.shadow                = false;
e.showScans             = false;
e.nScanLines            = 10;
e.units                 = 'm';

% Initialize the flux and temperature arrays
%-------------------------------------------
q    = zeros(length(g.component),nSamp);
temp = zeros(length(g.component),nSamp);

% Now run the simulation
%-----------------------
qLVLHToBody = Mat2Q([0 0 -1;0 1 0;1 0 0]);

[ ratioRealTime, tToGoMem ] =  TimeGUI( nSamp, 0 );

Loop through the disturbances

%-------------------------------
for k = 1:nSamp

  [ ratioRealTime, tToGoMem ] = TimeGUI( nSamp, k, tToGoMem, ratioRealTime, dTSim );

  % Update solar ephemeris
  %-----------------------
  [uSun, rSun] = SunV1(jD(k));
  e.s          = flux0*uSun;
  e.r          = rECI(:,k);
  e.v          = vECI(:,k);
  e.rSun       = rSun*uSun;

  % Sun vector
  %-----------
  qLVLH    = QLVLH( rECI(:,k), vECI(:,k) );
  uSunLVLH = QForm( qLVLH, uSun );
  theta    = atan2( uSunLVLH(1), uSunLVLH(3) );

  % CAD body structure
  %-------------------
  g.body(1).bHinge.q     = QPose(QMult(qLVLH,qLVLHToBody));
  g.body(2).bHinge.angle = theta;
  g.body(3).bHinge.angle = theta;
  g.rECI                 = rECI(:,k);
  g.qLVLH                = qLVLH;

  % Update the temperature
  %-----------------------
  p = SpacecraftThermal( 'run', g, e );

  % Draw the picture
  %-----------------
  [qCamera,rCamera,distance] = AutoPoint( 'above', camera, g );
  camera.rBody    = rCamera;
  camera.qBody    = qCamera;
  camera.distance = distance;
  g.temperature   = p.temperature;

  SpaceCamera( 'update camera',     tagVisibleCameraWindow,  camera, jD(k) );
  SpaceCamera( 'update spacecraft', tagVisibleCameraWindow,  g,      jD(k) );
  SpaceCamera( 'update camera',     tagInfraredCameraWindow, camera, jD(k) );
  SpaceCamera( 'update spacecraft', tagInfraredCameraWindow, g,      jD(k) );

  % For the plots
  %--------------
  q(:,k)    = p.qTotal;
  temp(:,k) = p.temperature;

  % TimeGUI control
  %-----------------
  switch simulationAction
    case 'pause'
      pause
      simulationAction = ' ';
    case 'stop'
      return;
    case 'plot'
      break;
  end
end

Plot the results

PlotThermal( q(:,1:k), temp(:,1:k), t(1:k), g );

%--------------------------------------

Published with MATLAB® R2021b