TITLE:
Reference Ellipsoid Parameters of Cameroon from GPS Data
AUTHORS:
Ludovic Houetchak Kande, Joseph Kamguia, Loudi Yap, Louis Foyang
KEYWORDS:
Ellipsoid, Parameters, Geoid, GPS, Molodensky Analytical Method, Cameroon
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.8,
August
19,
2016
ABSTRACT: The standard spheroidal
reference surface also referred as the reference ellipsoid is a part of mapping
basic infrastructures of a country. In Cameroon, the ellipsoid Clarke 1880 with
unknown parameters used for a long time as reference system in basic mapping,
has lead to the use of World Geodetic System 1984 (WGS 84) whose parameters are
well known. Meanwhile, the latter is not accurate locally due to the fact that
the best ellipsoid is the one that fits very well with the local geoid. In
order to look for the parameters of the local ellipsoid that fits best to the
local geoid (Cameroon Geoid Model 2011 (CGM11)), the Global Positionning System
(GPS) data made of 525 geodetic ground control points of the new geodetic
network of Cameroon set up in 2011 were used. These GPS measures provide for
each point the values of the ellipsoid height and the elevation which are used
to determine the parameters of the local ellipsoid model for Cameroon through
the least square form of the Molodensky analytical method. The results are given
as the difference in ellipsoidal height relative to the parameters of the WGS84
ellipsoid assuming the two ellipsoids in their parallel. These results show
that the obtained ellipsoid fits better to the local geoid with 1.072 m as the
standard deviation value, is improved considerably in comparison to the
previous studies conducted in Cameroon whose standard deviation was fairly
equal to 1.679 m.