The Definition and Realization of the Reference System in the SIRGAS Project

This paper describes the different stages executed to establish the Reference System to be used in the definition of the geocentric datum in South America, in the frame of the SIRGAS project.The Working Group I developed the activities to plane, to prepare and to coordinate the GPS measuring campaign, besides the processing organization to be executed by the calculating centers. The analysis and decision about the final solution, represented by the geocentric coordinates of the GPS network, are the last phase of the work.The GPS observations were carried out from May 26 to June 04, 1995. 58 principal stations were observed in 11 countries. The campaign was possible due to the collaboration of around 30 participant institutions from South, North America and Europe. DGFI (Germany) and NIMA (USA) were the processing centers.