Transformation of classical geodetic control networks 7to international terestrical reference frame by transformation grids

Abstract

In December 2005 a permanent stations network, as an augmentation system of Global Navigation Satellite System (GNSS), was established in Serbia and it has been in use since then and represents an official active geodetic referent network of Serbia (AGROS). After the network had been established activity on collecting data necessary for transformation of coordinates of classical geodetic networks, which are related to Bessel ellipsoid, into the international terrestrial referent frame (ITRF), i.e. the European Terrestrial Referent Frame (ETRF) started. By using AGROS, coordinates of trigonometric points that are relatively regularly distributed on Serbian territory were determined with the resolution of one point in 5 square kilometers. The strategy of transformation meant estimating 7 parameters of Helmert transformation (7P) for the whole territory of Serbia and then the modeling of the remaining residuals of transformation in the transformation grids (TG) and this was done for each of the coordinate axis. In this paper work a part of research related to the evaluation of parameters and usage of a series of methods of interpolation for the needs of modeling of transformation grids are shown.