IAG WG SC1.3 on Regional Dense Velocity Fields: First Results and Steps Ahead

Abstract

The Working Group on "Regional Dense Velocity Fields" (see http://epncb.oma.be/IAG) of the International Association of Geodesy (IAG) aims at densifying the International Terrestrial Reference Frame and creating a dense velocity field based on regional and global GNSS networks.With the goal to generate a high-quality solution for a core network, several newly reprocessed global and regional cumulative position and velocity solutions were submitted to theWorking Group. In order to find a consensus on discontinuity epochs for stations common to several networks (an issue which was problematic in previous submissions), the new submissions were restricted to contain only the core networks over which the analyst has full control so that ITRF2008 discontinuities could be applied. The 3D-RMS of the agreement of the new solutions with the ITRF2008 (after outlier rejection) varies between 0.6 and 1.1 mm/year; it is extremely good for some solutions, while others still require more iteration to reach the required level of agreement. A part of these disagreements has been identified and often originates in the use of different data time spans within the ITRF2008 and submitted solution. In the upcoming year, the Working Group expects to generate and use a discontinuity database complementing the ITRF2008 set and identify/solve the sources of disagreements. In addition, several of the regional solutions will be reprocessed to embed the regional network in a global network and reduce the error induced by the network effect. © Springer-Verlag Berlin Heidelberg 2013.