Global VLBI EOPS Solution 2008b
USNO Global VLBI TRF/EOP Solution 2008bJuly 2008

Presented here is the U.S. Naval Observatory's 2008b global VLBI EOPS
solution. The Batch SOLVE solution used all available
multibaseline VLBI observations at 8.4 GHz (Xband) and 2.2 GHz
(Sband) from 1979 August 3 through 2008 June 23. This
included a total of 3763 diurnal sessions and 5,317,776
measurements of group delay. The BATCH control
file
2008b.cnt along with databases given in
2008b.arc were used to generate this solution. The output spool
file is
2008b.spl.gz. Plotted and tabulated below are the global and
session RMS values for the solution.
Solution RMS delay and rate ( postscript , pdf ) Solution RMS histograms ( postscript , pdf ) RMS data file: 2008b.rms 
Earth Orientation Parameters
The Earth Orientation parameters: X and Y pole positions and rates, UT1 angle and rate, and daily offsets in the nutation in longitude and obliquity were estimated for each session separately. Plotted and tabulated below are these data.
Pole Position X vs. Y: Jan. 2000 to June 23 2008 ( postscript , pdf )  
Full EOP time series: X pole, Ypole, UT angle ( postscript , pdf )  
Full Nutation offset time series: Longitude and Obliquity ( postscript , pdf ) 
Tabulated EOP data.
EOP time series Solve format  2008b.eop  format description 
EOP time series IVS format  2008b.eops  format description 
Correlations between EOP estimates  2008b.crl  format description 
Station and Source Positions
Positions of 616 sources were estimated as global parameters. Sources which participated in 2 or more sessions, had 40 or more good observations, and normalized residual delays less than 1.3 qualified for the list of global sources. Positions for an additional 339 sources were estimated for each session independently as local parameters. A total of 138 sources were eliminated due to bad data or insufficient number (<3) of observations. Positions and velocites for 128 stations were estimated as global parameters.
Tabulated station and source data.
Station positions  2008b.sta  format description 
Station velocities  2008b.vel  format description 
Source positions  2008b.sou  format description 
Source position time series  2008b.lso  format description 
Solution Comparisons
Shown below is a comparison of the USNO 2008b solution with
the
IERS C04_05 time series. A weighted leastsquares fit
to the difference plots and the weighted rms are shown on each plot.
USNO  IERS C04_05 (19792008)  USNO  IERS C04_05 (20002008) 

Pole Position ( postscript , pdf )  Pole Position ( postscript , pdf ) 
UT1  UTC ( postscript , pdf )  UT1  UTC ( postscript , pdf ) 
Nutation Offset ( postscript , pdf )  Nutation Offset ( postscript , pdf ) 
Shown below is a comparison of the USNO 2008b solution with
the GSFC 2008a solution. A weighted leastsquares fit to
the difference plots and the weighted rms are shown on each plot.
USNO  GSFC (19792008)  USNO  GSFC (20002008) 

Pole Position ( postscript , pdf )  Pole Position ( postscript , pdf ) 
UT1  UTC ( postscript , pdf )  UT1  UTC ( postscript , pdf ) 
Nutation Offset ( postscript , pdf )  Nutation Offset ( postscript , pdf ) 
Shown below is a comparison of the USNO 2008b solution with
the previous USNO 2008a solution. A weighted
leastsquares fit to
the difference plots and the weighted rms are shown on each plot.
2008b  2008a (19792008)  2008b  2008a (20002008) 

Pole Position ( postscript , pdf )  Pole Position ( postscript , pdf ) 
UT1  UTC ( postscript , pdf )  UT1  UTC ( postscript , pdf ) 
Nutation Offset ( postscript , pdf )  Nutation Offset ( postscript , pdf ) 