Hybrid Geoid Model: Theory and Application in Brazil

Abstract

Determination of the ellipsoidal height by Global Navigation Satellite Systems (GNSS) is becoming better known and used for purposes of leveling with the aid of geoid models. However, the disadvantage of this method is the quality of the geoid models, which degrade heights and limit the application of the method. In order to provide better quality in transforming height using GNSS leveling, this research aims to develop a hybridization methodology of gravimetric geoid models EGM08, MAPGEO2015 and GEOIDSP2014 for the State of São Paulo, providing more consistent models with GNSS technology. Radial Basis Function (RBF) neural networks were used to obtain the corrector surface, based on differences between geoid model undulations and the undulations obtained by GNSS tracking in benchmarks. The experiments showed that the most suitable interpolation for correction modeling is the linear RBF. Checkpoints indicate that the geoid hybrid models feature root mean square deviation ± 0.107, ± 0.104 and ± 0.098 m, respectively. The results shows an improvement of 30 to 40% in consistencies compared with the gravimetric geoids, providing users with better quality in transformation of geometric to orthometric heights.

Computing Local Geoid Model Using DTM and GPS Geodetic Points. Case Study: Mejez El Bab-Tunisia

“…These models will contribute, in a significant way, to the realization of a Tunisian geoid of high accuracy. Indeed, it would be necessary to integrate various methods to reach the required precision (gravimetric collocation) [44] [45].…”

Validação do MAPGEO2015 e Determinação de um Geoide Local através de Posicionamento GNSS para a Mesorregiões Metropolitana de Belém e Nordeste Paraense

“…Uma alternativa que vem crescendo nos últimos anos é a integração de modelos geoidais com o nivelamento/ GNSS em pontos de uma rede altimétrica, de modo a modelar as distorções entre o modelo geoidal e o geoide considerado real (Arana, 2016;Brum et al, 2020). As literaturas chamam essas superfícies geradas de modelos geoidais locais (Cerqueira & Romão, 2010;Guerra Neto & Oliveira, 2018;Marotta et al, 2019;), geoides Híbridos (Lee et al, 2013;Arana et al, 2017) ou geoides geométricos (Kao et al, 2017;Brum et al, 2020). Nos resultados notase uma melhora ao nível centimétrico aos novos modelos.…”