THE INFLUENCE OF THE DEFLECTION OF THE VERTICAL ON GEODETIC SURVEYS IN BRAZIL

A influência do desvio da vertical nas medições geodésicas no Brasil

Abstract:

The densification of geodetic surveys using classical positioning techniques such as total stations may be necessary due to the quality of Global Navigation Satellite System (GNSS) positioning in urban canyons. However, the correction of distances and angles due to the deflection of the vertical (DV) is usually neglected in commercial softwares and internal software of total stations. Given that context, this research seeks to estimate the influence of DV on the horizontal geodetic positioning with total station in the Brazilian territory. Secondarily, it seeks to demonstrate the practical application of DV in the densification of geodetic networks. It is important to note that land surveys in Brazil must be connected to a geodetic network; therefore, the neglect of DV may degrade the positional quality of geodetic surveys. Results obtained indicate differences in horizontal geodetic positions of up to 45 ppm. Considering the desired positional quality of the geodetic network, such values demonstrate the importance of a proper correction for the DV.

Keywords:
geodetic networks; deflection of the vertical; distance measurement; error propagation; horizontal positioning