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Implement spherical harmonic representation of planetary gravity

`[`

implements the mathematical representation of spherical harmonic planetary gravity based
on planetary gravitational potential. This function calculates arrays of
`gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

)*N* gravity values in the *x*-axis,
*y*-axis, and *z*-axis of the Planet-Centered
Planet-Fixed coordinates for the planet. The function performs these calculations using
`planet_coordinates`

, an *M*-by-3 array of
Planet-Centered Planet-Fixed coordinates.

`[`

uses the degree and order that `gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

,`degree`

)`degree`

specifies.

`[`

implements the mathematical representation for the planetary model,
`gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

,`model`

)`model`

.

`[`

uses the degree and order that `gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

,`model`

,`degree`

)`degree`

specifies.
`model`

specifies the planetary model.

`[`

uses the specified `gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

,`model`

,`degree`

,`action`

)`action`

when input is out of range.

`[`

implements the mathematical representation for a custom model planet.
`gx`

`gy`

`gz`

]
= gravitysphericalharmonic(`planet_coordinates`

,`'Custom'`

,`degree`

,{```
datafile
dfreader
```

},`action`

)`datafile`

defines the planetary model. `dfreader`

specifies the reader for `datafile`

.

The function excludes the centrifugal effects of planetary rotation, and the effects of a precessing reference frame.

The spherical harmonic gravity model is valid for radial positions greater than the planet equatorial radius. Minor errors might occur for radial positions near or at the planetary surface. The spherical harmonic gravity model is not valid for radial positions less than planetary surface.

When inputting a large PCPF array and a high-degree value, you might receive an out-of-memory error. For more information about avoiding out-of-memory errors in the MATLAB environment, see Performance and Memory.

When inputting a large PCPF array, you might receive a maximum matrix size limitation. To determine the largest matrix or array that you can create in the MATLAB environment for your platform, see Performance and Memory.

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