Earth Gravity Models

class satkit.gravmodel

Earth gravity models available for use

satkit.gravity(pos, **kwds)

Return acceleration due to Earth gravity at the input position

Args:

pos (list[float] | satkit.itrfcoord | npt.ArrayLike[np.float])

Position as ITRF coordinate or numpy 3-vector representing ITRF position in meters

Keyword Arguments:

model (gravmodel) – The gravity model to use. Default is gravmodel.jgm3
order (int) – The order of the gravity model to use. Default is 6, maximum is 16

Returns:

npt.ArrayLike[np.float]

acceleration in m/s^2 in the International Terrestrial Reference Frame (ITRF)

Notes

For details of calculation, see Chapter 3.2 of: “Satellite Orbits: Models, Methods, Applications”, O. Montenbruck and B. Gill, Springer, 2012.

satkit.gravity_and_partials(pos, **kwds)

Gravity and partial derivatives of gravity with respect to Cartesian coordinates

Args:

pos (itrfcoord | npt.ArrayLike[np.float])

Position as ITRF coordinate or numpy 3-vector representing ITRF position in meters

Keyword Arguments:

model (gravmodel) – The gravity model to use. Default is gravmodel.jgm3
order (int) – The order of the gravity model to use. Default is 6, maximum is 16

Returns:

tuple[npt.ArrayLike[np.float], np.arrayLike[np.float]]

acceleration in m/s^2 and partial derivative of acceleration with respect to ITRF Cartesian coordinate in m/s^2 / m

For details of calculation, see Chapter 3.2 of: “Satellite Orbits: Models, Methods, Applications”, O. Montenbruck and B. Gill, Springer, 2012.