Instituto Brasileiro de Geografia e Estatística

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Geodesy

Introduction

Geodesy is the science which deals with the determination of the form, dimensions and the gravity field of Earth. In practical terms, the participation of IBGE, which is the institution in charge of such activities in the country, is characterized by the implementation and maintenance of the Brazilian Geodetic System (SGB). This system is formed by a set of stations materialized on the land, whose position serves as precise reference for various engineering projects – the construction of roads, bridges, mapping, geophysics, scientific surveys, among others.

Geodetic activities have undergone significant changes with the advent of the Global Positioning System (GPS). This system allows the determination of cinematic or static positions and combines levels of speed and precision above those obtained in standard surveying methods, and this feature demanded a revision of the characteristics of SGB. The implementation of the Brazilian Network for Continuous Monitoring (RBMC) represents the result of this discussion. With RBMC, the users of information provided by IBGE will have access to an active infrastructure, compatible with current positioning methods based on GPS. The altimetric component of SGB has not been completely covered because the real form of Earth (geoid) is not known with enough precision. Therefore, it is necessary to concentrate efforts on activities of geodetic leveling, tide gauge measurement, and gravimetry, which will lead to better knowledge of the geoid and its anomalies. Only then will it be possible to expand the use of GPS tools, especially in order to determine altitude figures.

News (in Portuguese)
  "Revista Ponto de Referência no 1" - August 2006
  "Revista Ponto de Referência no 2" - October 2007
  Change of the Geodetic Reference System