GNSS in Practical Determination of Regional Heights - Global Navigation Satellite Systems: Signal,Theory and Applications - page 133

EGM08 in terms of root mean square errors of geoid heights, these models can be employed
to obtain regional orthometric heights from GNSS heights for the applications that require a
decimetre level accuracy in heights.

*Model Degree Data Citation

EGM96 360 Satellite, gravity, altimetry Lemoine et al., 1998

EGM08 a 360 GRACE, gravity, altimetry Pavlis et al., 2008

EGM08 b 2190 GRACE, gravity, altimetry Pavlis et al., 2008

EIGEN-6C 1420 GOCE, GRACE, LAGEOS, gravity, altimetry Förste et al., 2011

EIGEN-6S 240 GOCE, GRACE, LAGEOS Förste et al., 2011

EIGEN-51C 359 GRACE, CHAMP, gravity, altimetry Bruinsma et al., 2010

GGM03C 360 GRACE, gravity, altimetry Tapley et al., 2007

GGM03S 180 GRACE Tapley et al., 2007

GOCO02S 250 GOCE, GRACE Goiginger et al., 2011

* Related to the global geopotential models that were used in the study: i -) The adopted reference
system is GRS80, ii -) The applied models are in tide free system, iii -) Zero degree terms were included in
computations, iv -) The model coefficients are available from ICGEM (2011).
Table 1. Validated global geopotential models in the study

Some other conclusions drawn from the statistical inspection of the validation results that
EGM08 provided improved results compared to its previous version EGM96 in the study
region (compare the statistics of EGM96 and EGM08 a in Table 2). Among the satellite only
models EIGEN-6S fits best, and as such, can be recommended as a reference model for a
future regional geoid of Turkey with R-R technique.

Model ℓ max Type min. max. mean std. dev.

EGM96 360 Combined -183.1 336.5 38.2 156.3

EGM08 a 360 Combined -105.0 47.6 -18.1 36.4

EGM08 b 2190 Combined -58.6 27.0 -4.5 17.3

EIGEN-6C 1420 Combined -41.9 28.3 -4.1 15.8

EIGEN-6S 240 Satellite only -77.5 85.0 -9.7 43.2

EIGEN-51C 359 Combined -126.2 50.5 -21.8 38.9

GGM03C 360 Combined -151.2 213.0 -2.4 76.3

GGM03S 180 Satellite only -394.3 331.4 -18.5 198.1

GOCO02S 250 Satellite only -87.2 90.9 -8.6 43.5

Table 2. Statistics of the geoid height differences between global models and observations
(in centimetre)

The geoid height differences of EIGEN-6C and EIGEN-6S global models from the observed
geoid heights at the reference benchmarks are illustrated in Figures 2 and 3, respectively.
These differences can be compared and interpreted considering the topographic map of
Turkey in Figure 1.