IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Seasonal effects in the weekly realization of the SIRGAS reference frame
Autor/es:
C. BRUNINI; H. DREWES; L. SÁNCHEZ,; V. MACKERN,; L. MATEO
Lugar:
Vienna, Austria.
Reunión:
Congreso; EGU General Assembly 2010.; 2010
Institución organizadora:
European Geosciences Union
Resumen:
Usually, epoch solutions (daily, weekly, multi-year) of regional
reference networks are aligned to the global reference frame
(ITRF) using a set of fiducial stations with known positions and
constant velocities. However, GNSS stations show significant
seasonal position variations (mainly in the up component)
resulting from a combination of geophysical loading and
systematic errors. Ignoring these seasonal variations at
reference stations can cause systematic errors in the datum
realization, and the reference networks can significantly be
deformed. These effects are larger in regional networks than
in global ones, especially in zones with strong seasonal
variations like the SIRGAS region (Fig. 1).
To evaluate the impact of seasonal variations in the weekly
realization of the SIRGAS frame, free normal equations are
solved applying two different sets of reference coordinates for
the datum realization: the first set corresponds to the IGS05
positions at epoch 2000.0 extrapolated to the observation
epoch using the ITRF2005 velocities (IGS05@2000 + VEL).
The second set corresponds to the weekly positions
determined for the IGS05 reference stations within the IGS
weekly combination (igsyyPwwww.snx).