During the past years it has been realized that the analysis of the global as well as the regional GNSS networks are affected by different factors like the reference system realization, correction models, analysis strategies and software packages. Therefore products provided by the IGS or the individual analysis centers in the form of precise orbits, ERPs or clocks are dependent on these different factors that were available at the time of generating these products. As a consequence the coordinates estimated by the EPN Local Analysis Centers (LAC) over the past decade are not consistent over the entire period of time. Inconsistencies in the time series of the coordinate appear most frequently whenever models (e.g. antenna PCV) or the reference frame realization were changed.

Global reprocessing activities have been started by the Potsdam-Dresden Group and later by the IGS. These reprocessing activities include the generation of orbits, EOPs and clocks. In the meantime different LACs of the EPN have started also their reprocessing activities using available orbits, EOPs and clocks. But all the groups acted individually and arrangements under the umbrella of EUREF were not made in advance. During the LAC workshop in Frankfurt in the end of October 2008 there was a general agreement to present to the EUREF TWG a plan for a coordinated reprocessing of the entire EPN, spanning the period from 1996 until 2009. This plan (charter on reprocessing) has been accepted by the TWG and lead to the formation of the EPN project Reprocessing.