****************************************************************************** EUREF Electronic Mail 02-Oct-2009 09:00:01 UTC Message Number 4647 ****************************************************************************** Author: EPN CB/C. Bruyninx Subject: EPN station classification and regular update of station coordinates Dear Colleagues, I would like to draw you attention to the fact that EUREF now updates each 15 weeks the original EUREF densification of the ITRF2005 (released on Dec 12, 2008 by EUREF mail 4142) taking the most recent EPN results into account. These regularly updated positions/velocities are the result of a multi-year adjustment of all the weekly combined EPN solutions in which outliers have been eliminated and station discontinuities were applied. In addition, in order to provide the most reliable products, the EPN stations are now categorized taking the station quality and the length of the available observation time span into account: - Class A: station positions have a 1 cm accuracy at all epochs of the time span of the used observations - Class B: station positions have a 1 cm accuracy at the epoch of minimal variance of each station. Only Class A stations are suitable as fiducial stations for the densification of the ETRS89! More details about the usage of the Class A stations for EUREF densifications are available from "Guidelines for EUREF Densifications" by Bruyninx et al., see ftp://epncb.oma.be/epncb/general/Guidelines_for_EUREF_Densifications.pdf For Class B stations, EUREF provides only position estimates at the epoch of minimal variance while the velocity estimates are not released because of their limited accuracy (caused by e.g. the short observation period of the station). The new EPN coordinates web page explains all the details and provides access to the new (and historical) EPN site coordinates at: http://www.epncb.oma.be/_trackingnetwork/coordinates/ Questions and comments are welcome at epncb@oma.be, Best regards, Carine Bruyninx Ambrus Kenyeres [Mailed from: Carine Bruyninx ] EUREF Mailing list maintained by epncb@oma.be and archived at ftp://epncb.oma.be/epncb/mail/ and http://epncb.oma.be/_newsmails/EUREFmail/