Path: Orbit/GravityModels
% Load a spherical harmonic gravity model from GSFC/University 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). -------------------------------------------------------------------------- Form: gravityModel = LoadGravityModel( action, fileName, normalized ) -------------------------------------------------------------------------- ------ Inputs ------ action (1,:) 'get url' or 'load file' fileName (1,:) fileName isNormalized (1,1) flag whether to output normalized (default) or not ------- Outputs ------- 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 --------------------------------------------------------------------------
Math: Linear/DupVect Math: Linear/Factorl
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