Small Trends and Oscillations in the 25 Year ILRS Translations and Scale Time Series

The new realization of the International Terrestrial Reference System, ITRF2008, follows the same strategy of ITRF2005 and is based on an inter-technique combination of geodetic solutions, in turn obtained from an intra-technique combination strategy performed at the Technique Centre (ILRS, IGS, IVS, IDS) level. In Summer 2009, ILRS has provided IERS with its official contribution to the ITRF2008: a homogeneous set of coordinate time series for the period 1983–2008, obtained by ASI/CGS ILRS Primary Combination Center combining time series sets of solutions provided by seven official ILRS Analysis Centers.A detailed analysis of the ILRS solution origin and scale parameters is presented looking at the time series of the translations and scale with respect to newly released ITRF2008. The analysis is made both for combined and individual solutions, to highlight especially their non-linear behavior; these tiny, non-linear, residual effects must be investigated and possibly minimized.