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Naval Meteorology and Oceanography Command U.S. Naval Observatory
Tuesday September 19, 2017

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Global VLBI Solution 2001c
August 2001

Presented here is the U.S. Naval Observatory 2001c 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 3 August, 1979 through 31 July, 2001.   This included a total of 2934 diurnal sessions and 2,938,321 measurements of group delay.   The Batch control file 2001c.cnt was used to generated this solution with an output spool file 2001c.spl.gz. Plotted and tabulated below are the global and session RMS values for the solution.
 

Solution RMS delay and rate 
(postscript, pdf

RMS data file:  2001c.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.  The data were filtered such that sessions with EOP formal errors greater than 30 nanorad or with correlations greater than 0.97 were removed.  This resulted in the removal of 154 sessions from the EOP data.  Plotted and tabulated below are these data.
 
Pole Position X vs. Y:  Jan. 1993 to Sept. 2001 (postscript, pdf
Full EOP time series:  X pole, Ypole, UT angle (postscript, pdf
Full Nutation offset time series:  Longitude and Obliquity  (postscript, pdf

 

Tabulated data.

EOP time series Solve format 2001c.eop format description
EOP time series IVS format 2001c.eob format description
Correlations between EOP estimates 2001c.crl format description

 

Station and Source Positions

Positions of 552 sources were estimated as global parameters. A source which participated in 2 or more sessions and had 40 or more good observations is in the list of global sources. A source which participated in 1 session and had 25 or more good observations is in the list of global sources also. Positions of other 145 sources were estimated for each session independently.   Positions of 137 stations and their velocities were estimated as global parameters.
 
 

Tabulated data.

Station positions 2001c.sta format description
Station velocities 2001c.vel format description
Source positions 2001c.sou format description
Source position time series 2001c.lso format description

Comparisons


Shown below is a comparison of the USNO 2001c solution with the IERS C04 time series.  A weighted least-squares fit to the difference plots and the weighted rms are shown on each plot.
 

USNO - IERS (1979-2001) USNO - IERS (1996-2001)
Pole Position  (postscriptpdf ) Pole Position  (postscriptpdf )
UT1 - UTC  (postscriptpdf ) UT1 - UTC  (postscriptpdf )
Nutation Offset  (postscriptpdf ) Nutation Offset  (postscriptpdf )

 

Shown below is a comparison of the USNO 2001c solution with the GSFC 2001c solution.  A weighted least-squares fit to the difference plots and the weighted rms are shown on each plot.
 

USNO - GSFC (1979-2001) USNO - GSFC (1996-2001)
Pole Position  (postscriptpdf ) Pole Position  (postscriptpdf )
UT1 - UTC  (postscriptpdf ) UT1 - UTC  (postscriptpdf )
Nutation Offset  (postscriptpdf ) Nutation Offset  (postscriptpdf )

 
 
 

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