Path: Orbit/GravityModels
% Load a spherical harmonic gravity model (.geo) from GSFC/U. of Texas at Austin.
The coefficients returned from this file are normalized by default. Pass true
for the last argument to unnormalize them.
This routine works with GEMT1, JGM2 and JGM3. JGM3 is the most accurate
earth gravitational model currently available. JGM2 is used by Vallado
in his book. GEMT1 is also available within the toolbox by typing
LoadGEM. The gravity files all have the suffix '.geo'.
NOTE
----
All these models are publicly available, however, the proper
authorizations to obtain the GEM-*, JGM-1, and JGM-2 models
should be directed to NASA/GSFC (Steve Klosko, internet:
klosko@ccmail.stx.com (Steve Klosko)). The request for other models
should be directed to UT/CSR (shum@csr.utexas.edu).
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Form:
gravityModel = LoadGravityModel( action, fileName, normalized )
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Inputs
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action (1,:) 'get url' or 'load file'
fileName (1,:) fileName
isNormalized (1,1) flag whether to output normalized (default) or not
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Outputs
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gravityModel (1,1) Data structure
.name (1,:) Model name
.mu (1,1) Gravitational constant (km^3/sec^2)
.a (1,1) Model earth radius (km)
.c (n,n) Cosine coefficients
.s (n,n) Sine coefficients
.j (1,n) Zonal harmonics
.isNormalized (1,1) Boolean
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Math: Linear/DupVect Math: Linear/Factorl
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