Tuesday

May 21, 2013

We present here an analysis of the effects of including VLBA-RDV data in global SOLVE solutions on estimation of EOP. This is a work in progress.  In the plots below, solutions which include only the MkIII/MkIV VLBI data correlated with the MkIII/MkIV correlators are labeled USNO and solutions which include both the MkIII/MKIV data plus data taken through the series of VLBA-RDV proposals and correlated with the VLBA correlator in Socorro, NM are labeled USNO+RDV.  The MkIII/MkIV data cover a time period from 1979-2001 and include approximately 2.5 million observations.  The VLBA-RDV data cover a time range of 1997-2001 (RDV01 - RDV24 inclusive) and add approximately 500,000 observations to the data set.  EOP solutions were made using the parameterization represented in this  SOLVE BATCH control file.  In addition to a comparrison of the USNO EOP solutions with and without the VLBA-RDV solutions, also shown below are comparisons of the USNO+RDV solution with the GSFC 2001c solution (which also includes the VLBA-RDV data),and with the IERS C04 series.

Shown below is a comparison of the USNO (MkIII/MkIV only) and the USNO+RDV (MKIII/MkIV+VLBA) earth orientation parameters as derived from the two solutions.  Plotted is the difference between the two solutions such that points which do not appear in both solutions (i.e. the VLBA-RDV points) do not appear in the plots.  These plots do show the effect that the VLBA-RDV data has on the global solution.  Indicated on each plot is a weighted least-squares fit to the difference and the weighted rms. The VLBA-RDV data has no negative effect on the global solution estimation of EOP.
 
 

Shown below is a comparison of the USNO+RDV solution with the GSFC 2001c solution.  Both solutions use the VLBA-RDV data.
 
 

Shown below is a comparison of the USNO+RDV solution with the IERS C04 time series.