Análise da acurácia em levantamentos topográficos sob diferentes condições de campo

Abstract

The increasing development of GNSS methods and techniques have given rise to questions about the methods and accuracy levels to carry out the surveys. It is not always possible to raise only points with this technology due to possible obstructions to GNSS signals that may exist in places of interest. This study aimed to evaluate the accuracy of surveys conducted with GNSS receivers and total stations under different field conditions and data processing. For this, we used three different methods of surveying. The relative static positioning fast with 5 time intervals and 30 minutes for screening, with the following data processing: processing by the Brazilian Monitoring Network Continuo (RBMC) Positioning by Precise Point (PPP) and processing using the coordinates of base station geodesic IBGE, this survey was conducted in a closed polygonal six vertices. The kinematic real-time (Real Time Kinematic - RTK) was performed by a polygonal traversal open under the following conditions: open, grid, tree canopy and buildings resulting in collecting 321 points. The intersection of the forward method used the total station to determine the coordinates of landmarks from geodetic coordinate reference obtained by GNSS. The results show that the best method for relative static surveying is fast screening with time of 30 minutes and processing by RBMC because it was the one that presented better accuracies and that fitted in all normative studies. In kinematic real-time condition field that causes greater variation in the horizontal and vertical was the canopy of trees. The geometric altitude values obtained by the intersection method to forward compared to geodetic altitudes obtained by GNSS showed the greatest variations in the field. It is concluded that the best methods for obtaining GNSS data is static relative positioning with rapid 30 minute time interval, processing the data and the kinematic RBMC in real time under open field conditions. Altitudes differ when using equipment with different calculation methodology.