Demonstrates the image matching algorithm, FImage.

Compute the cost for one of four test cases.

Since version 10.
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See also QForm, QLVLH, QMult, QPose, QUnit, Mag, Unit,
FindSolsticeOrEquinox, FImage, RVFromKepler, CameraDatabase, SpaceCamera
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Contents

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

clear d; clear g; clear w;

Select test case (rx, ry, rz, qx)

%-----------------
test = 'ry';

g = load('SCForImaging');
g.body(2).bHinge.angle = 0;
g.body(2).bHinge.axis  = 2;
g.body(3).bHinge.angle = 0;
g.body(3).bHinge.axis  = 2;

Ephemeris - geosynchronous orbit

%----------
jD            = FindSolsticeOrEquinox('spring equinox',2002);
[rECI, vECI]  = RVFromKepler( [42167 0 0 0 0 0], 0 );
uSun          = SunV1(jD);

Camera

%-------
d                         = struct;
d.camera                  = CameraDatabase('256 square');
d.camera.up               = [0;-1;0];
d.camera.focalLength      = 0.1;
d.camera.aperture         = 0.1;
d.camera.rho              = 0.03;

Initialize the picture

%-----------------------
qLVLH                   = QLVLH( rECI, vECI);
g.body(1).bHinge.q      = QPose(qLVLH);
g.rECI                  = rECI;
g.qLVLH                 = qLVLH;
g.name                  = 'Satellite';
d.position              = [];

Earth vector

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

CAD body structure

%-------------------
g.body(1).bHinge.q     = QPose(qLVLH);
g.body(2).bHinge.angle = theta;
g.body(3).bHinge.angle = theta;
g.rECI                 = rECI;
g.qLVLH                = qLVLH;

Draw the picture

%-----------------
d.camera.rBody    = 1.000002*g(1).rECI*1000;
d.camera.distance = 0.000002*Mag(g(1).rECI)*1000;
qBodyToECI        = g(1).body(1).bHinge.q;
d.camera.qBody    = QPose( qBodyToECI );

tagVisibleCameraWindow  = SpaceCamera( 'initialize', d, g, jD(1) );
SpaceCamera('update camera',     tagVisibleCameraWindow,  d.camera, jD );
SpaceCamera('update spacecraft', tagVisibleCameraWindow,  g,        jD );

Create the data structure

%--------------------------
w        = struct;
w.image  = SpaceCamera( 'get frame', tagVisibleCameraWindow );
w.g      = g;

kTest = 1;
switch test
  case 'ry'
    w.rECI0 = rECI + [0;.001;0]; % Example 1
    w.q0    = g.body(1).bHinge.q;
    kTest   = 5;

  case 'rz'
    w.rECI0 = rECI + [0.0;0;.001];% Example 2
    w.q0    = g.body(1).bHinge.q;
    kTest   = 6;

  case 'rx'
    w.rECI0 = rECI + [0.001;0;0]; % Example 3
    w.q0    = g.body(1).bHinge.q;
    kTest   = 4;

  case 'qx'
    w.rECI0 = rECI; % Example 4
    dQ      = QUnit([1;0.1;0;0]);
    w.q0    = QMult( g.body(1).bHinge.q, dQ );
end

w.tag    = SpaceCamera( 'initialize', d, g, jD );
w.jD     = jD;

% The state vector x is [dQ;rECI]
%--------------------------------
x0      = [0;0;0;0;0;0];
x       = x0;
y       = [-0.001 0 0.001];
cost    = zeros(1,length(y));

for k = 1:length(y)
  x         = x0;
  x(kTest)  = y(k);
  cost(k)   = FImage( x, w );
end


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% PSS internal file version information
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Published with MATLAB® R2014b