Preliminary results of processing of EUREF observations
using non-fiducial strategy.

Zinovy Malkin, Alexander Voinov
Institute of Applied Astronomy RAS

Analysis of the official EUREF weekly solution series reveals some
systematic seasonal errors, especially in the height component.
We suspect that the standard fiducial processing strategy causes
these errors.  In the present investigation the non-fiducial strategy
has been used to process a subnetwork of 21 EUREF station for GPS weeks
969-1042: free weekly solutions obtained as Helmert-based combinations
of daily solutions followed by Helmert transformation to ITRF.  Bernese,
PyGPS and GROSS packages were used.  Comparison to the official EUREF
solution shows that obtained coordinate time series most likely are
free from seasonal errors.  The authors consider it important for such
a solution to accompany the official one.  A comparison of our EUREF
solution and the VLBI one, obtained at the IAA, is planned.