Abstract
The Earth orientation parameters (EOP), the regular products of IERS
Earth Orientation Centre, are computed at daily bases by combination of
EOP solutions by different astro-geodetic techniques. At SYRTE we have
developed a new strategy of combination using the Global Navigation
Satellite Systems (GNSS) and Very Long Baseline Interferometry (VLBI)
techniques at normal equation level thanks to the IERS COL-WG [1].
This approach allows to produce the EOP at the daily bases, polar
coordinates (x,y) and rates (xr,yr), universal time UT1 and rate LOD,
and corrections from IAU200A/2006 precession-nutation mode (dX,dY),
simultaneously with station coordinates constituting the terrestrial
frame (TRF) and possibly the quasar coordinates constituting the
celestial frame (CRF). For studying these EOP solutions continuously
with respect to the IERS EOP products, we have developed an operational
process which take the recently solution files produced respectively by
IGS and IVS international services which are converted at normal
equation level. The recorded solutions obtained from GNSS and VLBI
combination at weekly bases is recently maintained by SYRTE. The process
of this combination are presented and results are analysed.