Path: Orbit/OrbitMechanics
% Compute the gravitational acceleration in cartesian coordinates.
Acceleration vectors are a [ aX;aY;aZ ].
If the gravity coefficients are normalized, an additional matrix
multiplication is required. The normalization matrix is stored as a persistent
variable but AGravityC will gracefully update it if the normalization or order
of the model changes between calls.
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Form:
[aG, aS, aZ, aT] = AGravityC( r, nN, nM, d ) % structure
[aG, aS, aZ, aT] = AGravityC( r, nN, nM, s, c, j, mu, a, useNormM )
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Inputs
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r (3,:) Position vector, planet-fixed
nN (1,1) Highest zonal harmonic (m = 0)
(empty gives the max #)
nM (1,1) Highest sectorial and tesseral harmonic
(empty gives the max #)
d (.) Gravity model struct
-or-
s (:,:) S terms
c (:,:) C terms
j (:) m = 0 terms
mu (1,1) Spherical gravitational potential
a (1,1) Planet radius
useNormM (1,1) Generate the normalization matrix (default false)
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Outputs
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aG (3,:) Total gravitational acceleration km/sec^2
aS (3,:) Spherical term km/sec^2
aZ (3,:) Zonal term km/sec^2
aT (3,:) Tesseral term km/sec^2
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Reference: Bond, V. R. and M. C. Allman (1996.) Modern Astrodynamics.
Princeton. pp. 212-213.
Lerch, F. J., Klosko, S. M., Labuscher, R. E., Wagner,
C.A., "Gravity Model Improvement GEOS-3 (GEM 9 & 10),"
N78-10645, September, 1977.
Gottlieb, R. G., "Fast Gravity, Gravity Partials, Normalized
Gravity, Gravity Graident Torque and Magnetic Field:
Derivation, Code and Data, NASA CR 188243, February, 1993.
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See also UnnormalizeGravity, AGravity (output in spherical coords)
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Orbit: GravityModels/LoadGEM Orbit: GravityModels/NormalizationMatrix SC: SCMat/GEMT1 Common: CommonData/SwooshWatermark Common: General/CellToMat Common: General/DeBlankLT Common: General/DispWithTitle Common: General/MatToCell Common: General/Watermark Common: Graphics/Mesh2 Common: Graphics/NewFig Common: Graphics/Plot2D Common: Graphics/PltStyle Common: Graphics/XLabelS Common: Graphics/YLabelS Common: Graphics/ZLabelS Math: Linear/DupVect Math: Linear/Factorl
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