.. _glossary:
Glossary
========
.. glossary::
Reference ellipsoid
An ellipsoid with geometric and physical properties used to best
approaximate a given planetary body (the Earth or others).
See `Wikipedia `__.
Geocentric gravitational constant
The multiplication of the total mass of a :term:`reference ellipsoid`
and the `gravitational constant
`__. Often
represented as :math:`GM`.
Normal gravity
The magnitude of the gradient of the :term:`gravity potential` of a
:term:`reference ellipsoid`.
Gravity potential
The combined gravitational and centrifugal potential
:math:`U = V + \Phi` [HofmannWellenhofMoritz2006]_.
Gravity disturbance
The gravity disturbance is the difference between the magnitude of
observed gravity and the magnitude of normal gravity evaluated at the
same point [HofmannWellenhofMoritz2006]_:
:math:`\delta g(\lambda, \phi, h) = \|\vec{g}(\lambda, \phi, h)\| - \|\vec{\gamma}(\lambda, \phi, h)\|`