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

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rotating earth

Global VLBI Solution 2001d
October 2001

rotating earth

Presented here is the U.S. Naval Observatory's 2001d 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 09 October, 2001.   This included a total of 2895 diurnal sessions and 2,844,574 measurements of group delay.   The Batch control file 2001d.cnt was used to generated this solution with an output spool file 2001d.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:  2001d.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 145 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 2001d.eop format description
EOP time series IVS format 2001d.eob format description
Correlations between EOP estimates 2001d.crl format description

 

Station and Source Positions

Positions of 527 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 in the CRF2001a solution qualified for the list of global sources. Positions for an additional 140 source were estimated for each session independently as local parameters. Positions of 129 stations and velocities for 118 of those stations were estimated as global parameters.
 
 

Tabulated data.

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

Comparisons


Shown below is a comparison of the USNO 2001d 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  ( 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 2001d solution with the GSFC 2002a 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  ( 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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