Evaluation of recent global geopotential models by GNSS/levelling data: Internal Aegean region

Year 2016, Volume: 1 Issue: 1, 18 - 23, 01.10.2016

Mustafa YİLMAZ Bayram TURGUT Mevlüt GULLU İbrahim YİLMAZ

https://doi.org/10.26833/ijeg.285221

Cited By: 10

Abstract

Global geopotential models of spherical
harmonic coefficients are used to determine the external gravitational field of
the Earth. These coefficients are derived from satellite orbit perturbations,
terrestrial gravity anomalies and altimeter data. Hundreds of thousands of
coefficients and standard deviation values for these coefficients are estimated
from millions of observation. Measurement amount, homogenous distribution of
the measurements of global scale, different measurement types reflecting the
different frequencies of the gravity signal and measuring-assessment techniques
affect the model accuracy directly. Starting from 1960’s and lasts to the
present day and also gaining new acceleration with the satellite gravity field
missions, every outcome of the studies related to the determination of the
global Geopotential model is experienced by a series of validation tests.
Accuracy of the model can either be determined from the estimated error degree
variances concerning the coefficients (interior validation) or comparison of
geoid heights, gravity anomalies, gravity disturbances and components of
vertical deflection calculated from the model with terrestrial measurements
directly (outer validation). In this paper, recent global geopotential models
are primarily explained. Global geopotential models are compared with GNSS/levelling
data of the study area. The objective of this comparison is to determine the
best fit global geopotential model which will contribute to the study of
Turkish geoid determination.

Keywords

Geoid, Geopotential model, GNSS/levelling

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