Analysis of Regional GPS Campaigns and their Alignment to the International Terrestrial Reference Frame (ITRF)

The main objective of this study is to test the impact of the alignment of solutions for regional GPS networks to the ITRF when applying an inappropriate procedure which is adopted fairly frequently in practice. The progression of ITRF versions is overviewed then, using the analysis of two regional GPS campaigns as case studies, the coordinate differences caused by applying the inappropriate procedure for reference frame alignment are presented. The results of the comparative studies show that coordinate differences in the order of a few millimetres to some centimetres can be caused by using inconsistent reference frames for the reference station coordinates and the IGS satellite orbits. Subsequent analysis demonstrates that there are no significant coordinate differences introduced when applying different subsets of IGS reference stations to link the regional GPS network to ITRF.