Exatidão das coordenadas topográficas de pontos obtidas a partir de levantamentos geodésicos com receptor GPS L1-L2 no método relativo semiestático

Abstract

The appearance the satellite of geodesy revolutionized the geodesic survey. However, the utilization of results obtained in surveys of local topographic planes, using the traditional methodology, present some operational problems. A methodology, in which Earth rotation movements are applied to the Tridimensional Orthogonal Cartesian System in order to transform it into a system of local geodesic terrestrial coordinates can be used, giving precise results and accuracy compatible to the application. The objective of this study was to obtain a terrain digital model (TDM),based on point coordinates gathered via GPS set on the rapid static method, and to transform them in local coordinates, comparing this model to the one gained from the coordinates determined through electronics tacheometry To do so a double frequency GPS receiver and a total station were the equipments used in this survey. The comparative study was done in an area of the city of Santa Maria (RS, Brazil), and the results of local coordinates accquired from the GPS coordinates, were compatible with plans of B and C classes in a scale of 1:1000 or less, as well a with level curves of equidistance level of one meter, according to the established by the 89.817/84 Decree, or in a scale of 1:2500 with level curves spaced out in one meter and a half, when these refer to specifications of NSSDA.