GPS Data Processing of Five Years of More Than 300 Permanent Station Database With the Distributed Sessions Approach Using Gamit/Globk 10.5 Data Analysis Software in Italian Peninsula

We processed an archive of more than 300 permanent Global Navigation Satellite Systems (GNSS) station with the aid of software Gamit/Globk 10.5 developed and maintained by MIT, Scripps Institution of Oceanography, and Harvard University with support from the National Science Foundation (http://www-gpsg.mit.edu/~simon/gtgk/), using our facilities based on the distributed sessions approach implemented in the package. The Global Positioning System (GPS) data are comprised in the period January 2008 – December 2012, and belongs to several different permanent GPS network in Italy like: the RING of the National Institute of Geophysics and Volcanology (INGV), ASI Italian spatial agency, EUREF – European Reference Network, IGS – International GNSS Service for geodynamics, ITALPOS of Leica Geosystems and other institution networks maintained by public and private administration and universities. The data collected daily by different sensors and archived in RINEX compressed Hatanaka format were gathered, divided in several clusters, and routinely processed using Gamit data processor, based on least square method.
Successively, our solutions were combined with SOPAC (http://garner.ucsd.edu) ones to obtain stable and high quality solutions (h_files) containing coordinates, velocities and covariance of more than 300 GPS sites. A Global Kalman filter based package (Globk) was used to compute position time series and velocities registered in the ITRF2008 reference frame. The almost rigid rotation of the Eurasian plate was removed using Altamimi’s definition of rotation pole, and residual intra-plate velocities for all the 300 stations were computed. Indications about the tectonics of Mediterranean regions can be available by studing the computed high density velocity field.