Effect global digital elevation model [GDEM] in geoid modelling using [KTH] method / Afiqah Zol

Geoid model gave information in determination of orthometric height by knowing the
ellipsoidal height. This ellipsoidal height using Global Navigation Satellite System (GNSS)
technology. The main objective is to determine precise geoid models. There are several of
method in determine geoid at any country such as Remove- Compute-Restore (RCR) method.
In this study, the Least Square Modification Stokes' (LSMS) approach by Royal Institute of
Technology, (KTH) had been the aim for the evaluated in determine gravimetric geoid model
in Johor region. In order to increase the accuracy of geoid model. Global Geopotential Model
(GGM) along with Digital Elevation Model (DEM) are need. So that it achieved in study focus
which is evaluation of DEM and GGM. The result of this study is one of three GGM were
evaluate and ITU_GGC16 is the most precise global model that produce Root Mean Square
Error (RMSE) with 0.22m over 3367 gravity points. In additional, in DEM evaluation, the
SRTM30 show the RMSE with 7.12m. Furthermore, the precise gravimetric geoid model show
that Aster using ITU_GGCI6 show precise than SRTM30 and SRTM90 with 1.365m. The
comparison between RCR method where JUPEM used and KTH approach show that the LSMS
method is better in determine precise geoid model for Johor region.