Tuesday 23 August 2005

G2

PT0013
The present initiatives for improvements on the geoid South America
Blitzkow, Denizar¹, Lobianco, Maria Cristina B.², Matos, Ana C O C de¹
1 University Of São Paulo, Brazil
2 IBGE-Department of Geodesy, Brazil
Author email: dblitzko@usp.br
The facilities of the Global Positioning System - GPS for the determination of the geometric height raised a great interest for the geoid (quasi-geoid) height. If this one is known with compatible accuracy of the GPS geometric height, the orthometric height can be obtained at the same level of accuracy. Instituto Brasileiro de Geografia e Estatística- IBGE and Escola Politécnica da Universidade de São Paulo- EPUSP with many different organizations in Brazil and other countries in South America have been working on improvements of data. DTM is one of the efforts with the integration of SRTM, topographic maps in the continent and bathymetric data in the ocean area. Specific softwares have been set up to compute terrain correction and indirect effect for the geoid application. GPS observations on the leveling network have also been organized to validate the geoidal heights derived from the combination of geopotential model with gravity data. A grid of 5' Helmert gravity anomalies was generated for a block delimited by 60°S and 25°N in latitude and 100°W and 25°W in longitude. With all the improvements a new version of the geoid for South America was derived using FFT and numerical integration approaches.

Return to Poster Presentations