O Modelo Geoidal de Goiás – MODGEO-GO

Abstract

The limitations imposed by the Brazilian biomes, linked to socioeconomic issues, have greatly hampered the implementation of a geodetic framework in part of the country. Due to these circumstances there are several areas devoid of geodesic infrastructure, leading the user community to adopt alternative solutions, some of which are inadequate. Regarding the planimetric component, the GNSS-related options fully meet common needs. However, when vertical positioning needs to be determined accurately, the altitudes provided by the GNSS do not serve most of the trivial applications demanded by major engineering works, especially those involving water lows. To make it possible to obtain precise altitudes linked to the terrestrial gravity field, it is necessary to have a geoid model, which is why the aim of this paper was to elaborate a state geoid model to contemplate all the user segments that need consistent attitudes. For this, the modiied Stokes integral was used by means of the Fast Fourier Transform. The spectral decomposition was used in the calculation of the models, and the long wavelength component was represented by the EIGEN-6C4, GOCO05C and GECO models up to degree and order 200 and 250. The models were compared in terms of absolute comparisons from 140 stations GNSS over leveling. The results of the three models were consistent with each other with a standard diference of around 10 cm.