Toward a dense italian GPS velocity field: data analysis strategies and quality assessment

Abstract

A test combination procedure of loose constrained SINEX solutions has been set up with the aim to integrate different network solutions (clusters of GPS site coordinates) processed by different analysis groups. Two solution types have been combined on a daily basis, one cluster of about 60 sites processed with the Bernese software and a second cluster of about 30 sites processed with the Gamit software. The chosen networks consists in 15 overlapping EUREF sites on which the combination test is figured out. In origin each solution is obtained in a loose constrained reference frame and archived in SINEX format, the full time series span a period of 2.5 years. If the reference frame constraints, if present, are conveniently relaxed in the original solutions, the combination of daily solutions can be carried out without the removal of relative rotations between reference frames and the different contributing SINEX solutions may be merged (in a least squares sense) into a combined consensus solution. The corresponding velocity fields, computed for the common sites, are consistent with respect to each other and the combined time series show a repeatability of a few millimeters in the vertical and 1–2 millimeters in the horizontal components respectively.