Appropriate Use of the International Reference Frames in Regional GPS Applications: Guidelines and Examples

The growing number of GPS permanent stations, in Europe as in the rest of the world, makes them very interesting not only for their original scientific or global geodesy purposes, but also for many current technical applications (e.g. photogrammetric, cartography, GIS data collection, cadastral surveys, etc.). In the first part of this paper, the basic definitions of the most important global reference frames will be briefly resumed, underlining some important aspects which must be understood for a correct use of the frames in the applications. In the second part, some numerical examples will be presented and discussed. These concern recurring technical problems, testing the correctness of the theoretical assumptions and estimating the position errors deriving from the use of inappropriate procedures. Finally, a few guidelines for the practical utilization of the frames will be derived from the above results.