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Naval Meteorology and Oceanography Command U.S. Naval Observatory
Wednesday March 29, 2017

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USNO TRF/EOP Solution 2008b  

rotating earth

Global VLBI TRF/EOP Solution 2008b
  July 2008

rotating earth

Presented here is the U.S. Naval Observatory's 2008b global solution.   The Batch SOLVE solution used all available multi-baseline VLBI observations at 8.4 GHz (X-band) and 2.2 GHz (S-band) 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

RMS plot  RMS histogram

 

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 Pole position plot
Full EOP time series:  X pole, Ypole, UT angle ( postscript , pdf EOP plot
Full Nutation offset time series:  Longitude and Obliquity  ( postscript , pdf Nutation offsets plot

 

Tabulated 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 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

Comparisons

Shown below is a comparison of the USNO 2008b solution with the IERS C04_05 time series.  A weighted least-squares fit to the difference plots and the weighted rms are shown on each plot.
 

USNO - IERS C04_05 (1979-2008) USNO - IERS C04_05 (2000-2008)
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 least-squares fit to the difference plots and the weighted rms are shown on each plot.
 

USNO - GSFC (1979-2008) USNO - GSFC (2000-2008)
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 least-squares fit to the difference plots and the weighted rms are shown on each plot.
 

2008b - 2008a (1979-2008) 2008b - 2008a (2000-2008)
Pole Position  ( postscript pdf ) Pole Position  ( postscript pdf )
UT1 - UTC  ( postscript pdf ) UT1 - UTC  ( postscript pdf )
Nutation Offset  ( postscript pdf ) Nutation Offset  ( postscript pdf )





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