Computation of the millimeter geoid with notable remark on the mandatory assumptions and limitations
21/09/2016 | 15:45 | Session 3: Regional and Local Geoid Modelling
Author(s): Olga Bjelotomic, Danko Markovinovic and Tomislav Basic
Olga Bjelotomic, Danko Markovinovic and Tomislav Basic
This study presents a successful determination of a local millimeter geoid model and discuss over an imposed concerns related to the vertical datum based on such geoid model. The geoid model is computed over a small area of 600km2 in central Croatia, with the KTH method. The area is unique regarding its densely coverage with terrestrial gravity data, even 6 points/ km2. The accuracy of computed geoid model is +/- 0.4 cm, enabling it as a possible reference surface for a vertical datum. Gaining towards a hybrid geoid-based vertical datum, a sub-centimeter solution of a geoid model is an unconditional requirement, but once accomplished it opens a wider discussion; how big are the errors transferred in the final solution through the assumptions made as conditio-sine-qua-non prior to computations such as the GNSS, levelling error or the geopotential and elevation model bias. Additionally, this work studies the question what practical reliability can a vertical datum defined on such geoid model produce regarding the model’s computational resolution and terrain on which it is stretching over.