1. EGS Nice 2003 G17 Deficits of CEGRN Solutions and Time Series G. Stangl

2. EGS Nice 2003 G17 CEGRN solutions Solutions 1994, 1995, 1996, 1997, 1999, 2001 Based on international standards (IGS/EUREF) ITRF systems GRAZ common reference Estimated station velocities Estimated zenith delays

3. EGS Nice 2003 G17 CEGRN Solution deficits Observation deficits Adjustment deficits Deficits of the reference frame Missing formal acceptance

4. EGS Nice 2003 G17 CEGRN Observation Deficits <3 periods for 66% of sites Epoch stations with observation errors (antenna height) Loss of sites (Epoch->permanent) -> restart of time series Neglecting other GPS sources (new permanent stations, regional geodynamic projects)

5. EGS Nice 2003 G17 Adjustment deficits Not all LACs participating Some stations excluded by different LACs Zenith delays not constrained to common solution

6. EGS Nice 2003 G17 Deficits of the Reference Frame Centred to ITRF97 (GRAZ) -> no transformed orbits Improved ITRF2000 values not yet introduced (esp. velocities) Constraints in CETRF questionable (configuration, antenna changes at reference sites, changes in velocities)

7. EGS Nice 2003 G17 Missing Formal Acceptance No new stations admitted within area Area of investigation focuses on countries, not on tectonic units No official permanent monitoring No international sub-network status

8. EGS Nice 2003 G17 Conclusions Increase number of occupations (20-30 epoch sites) Include useful sites and projects Readjust all campaigns to a more consistent reference frame (e.g. ITRF2000)