Compare various orbit propagators with a Topex ephemeris.

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See also Plot2D, TimeLabl, Date2JD, RVOrbGen, PropagateOrbitPlugIn,
ReadTopexPOE, RV2El, S2HMS
------------------------------------------------------------------------

Contents

%--------------------------------------------------------------------------
%   Copyright (c) 2000 Princeton Satellite Systems, Inc. All rights reserved.
%--------------------------------------------------------------------------

d                = ReadTopexPOE( '92dec22-92dec30.poe', 10 );

jD(1)            = Date2JD( d.uTC(1) );
jD(2)            = Date2JD( d.uTC(2) );
dT               = 86400*(jD(2) - jD(1));
nSim             = length( d.uTC );
t                = (0:(nSim-1))*dT;
x0               = d.xECI(:,1);
el               = RV2El( x0(1:3), x0(4:6) );
[r, v]           = RVOrbGen( el, t );
[time, xLabl]    = TimeLabl( t );
n                = size(r,2);
h                = Plot2D( time(1:n), d.xECI(1:3,1:n) - r, xLabl,...
                           ['X (km)';'Y (km)';'Z (km)'], 'Kepler' );

Initialize

%-----------
tag              = PropagateOrbitPlugIn( 'initialize' );
p                = PropagateOrbitPlugIn( 'get data', tag );

Spherical

%----------
p.epoch.jD       = jD(1);
[hh,mm,ss]       = S2HMS( t(end) );
p.epoch.duration = sprintf( '%2i:%2i:%f', hh, mm, ss );
p.epoch.dT       = dT;
p.elements.r     = x0(1:3);
p.elements.v     = x0(4:6);

PropagateOrbitPlugIn( 'set data',    tag, p );
PropagateOrbitPlugIn( 'propagate',   tag );
PropagateOrbitPlugIn( 'close plots', tag );

r = PropagateOrbitPlugIn( 'get r', tag );
n = size(r,2);
if( ~isempty(r) )
  h = Plot2D( time(1:n), d.xECI(1:3,1:n) - r, xLabl,...
             ['X (km)';'Y (km)';'Z (km)'], 'Propagator (spherical)' );
end

Zonal

%------
p.f.nZonal         = 4;
p.f.nTess          = 0;
p.gravityModelName = 'GEMT1';

PropagateOrbitPlugIn( 'set data',    tag, p );
PropagateOrbitPlugIn( 'propagate',   tag );
PropagateOrbitPlugIn( 'close plots', tag );

r = PropagateOrbitPlugIn( 'get r', tag );
n = size(r,2);
if( ~isempty(r) )
  h = Plot2D( time(1:n), d.xECI(1:3,1:n) - r, xLabl,...
              ['X (km)';'Y (km)';'Z (km)'], 'Propagator (Zonal)' );
end

Add tesseral

%-------------
p.f.nZonal         = 4;
p.f.nTess          = 4;
p.gravityModelName = 'GEMT1';

PropagateOrbitPlugIn( 'set data',    tag, p );
PropagateOrbitPlugIn( 'propagate',   tag );
PropagateOrbitPlugIn( 'close plots', tag );

r = PropagateOrbitPlugIn( 'get r', tag );
n = size(r,2);
if( ~isempty(r) )
  h = Plot2D( time(1:n), d.xECI(1:3,1:n) - r, xLabl,...
              ['X (km)';'Y (km)';'Z (km)'], 'Propagator (Zonal and Tesseral)' );
end

Add planetary

%-------------
p.f.nZonal                  = 4;
p.f.nTess                   = 4;
p.f.planetaryDisturbancesOn = 1;
p.gravityModelName          = 'GEMT1';

PropagateOrbitPlugIn( 'set data',    tag, p );
PropagateOrbitPlugIn( 'propagate',   tag );
PropagateOrbitPlugIn( 'close plots', tag );

r = PropagateOrbitPlugIn( 'get r', tag );
n = size(r,2);
if( ~isempty(r) )
  h = Plot2D( time(1:n), d.xECI(1:3,1:n) - r, xLabl, ['X (km)';'Y (km)';'Z (km)'], 'Propagator (Zonal, Tesseral, Planetary)' );
end

List of figures

Figui;


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

Published with MATLAB® R2019a