Abstract:
Abstract In Geodesy, the heights of points are normally
orthometric heights measured above the geoid (an equipotential
surface created by the earth masses and rotation which
approximately coincides with the mean sea level) or the normal
heights. It is necessary to transform the GNSS/GPS measured
ellipsoidal heights (h) to classical physical heights
(orthometric H/Normal H). The total gravity potential of the
earth (W) is the summation of two components; gravitational
potential (V) by earth masses and the centrifugal potential (Ω).
The centrifugal potential is directly calculated, while the gravitational
potential (V) needs to be modeled globally or locally
using given measurements. The global models of the earth
gravitational potential/gravity models (or so-called geoid
models) are mostly given using spherical harmonics (SH). A
modified approach of SH was defined to fit the use of SH for
regional gravity/potential modeling called spherical cap harmonics
(SCH). Due to the numerical difficulties of SCH, a
simplified approach of SCH is selected to be used for a combined
modeling of the earth potential using a variety of observations.
This approach is called the Adjusted Spherical Cap
harmonics.
