GNGTS 2016 - Atti del 35° Convegno Nazionale

206 GNGTS 2016 S essione 1.2 a simple geographic criterion, while maintaining the as shortest as possible baseline. The daily loosely constrained solutions of each cluster obtained after GAMIT processing have been combined into a unique solution by the GLOBK software (Herring et al. , 2015b) and aligned into the ITRF2008 reference frame (Altamimi et al. , 2012) by a weighted seven parameters transformation, using the ITRF2008 coordinates and velocities of the following 16 high-quality common IGS stations: AJAC, BUCU, GRAZ, IENG, LAMP, MATE, NOT1, ORID, PNEC, SFER, SOFI, TLSE, VILL, WTZR, YEBE and ZIMM (inset in Fig. 1). For each site with an observation period longer than 2.5 years, the time pattern of the north, east and vertical components of the position has been modelled by the procedure described by Cenni et al. (2015, Fig. 1 – Distribution of the continuous GNSS stations used in this work. The inset shows the 16 IGS stations we have used to align the network to the ITRF2008 reference frame (Altamimi et al., 2012).