0 - Technical description of solution aus2004a.crf

 1 - Technique:   VLBI

 2 - Analysis Centre:
     Geoscience Australia

 3 - Software used:
     OCCAM 6.1

 4 - Data span:
     April, 1980 - May, 2004

 5 - Celestial Reference Frame: ga2002a

     a - Nature:

         extragalactic

     b - Definition of the orientation: NNR Constrains for the
         207 sources (as treated for the ICRF-Ext.2 [Fey, et
         al.; 2004])

 6 - Terrestrial Reference Frame: itrf2000 and associated
                                  itrf2000 velocity field


     a - Relativity scale:

         Solar System Bary Center (SSB)

     b - Velocity of light:

         299792458 m/s

     c - Geogravitational constant:

         not applicable

     d - Permanent tidal correction:

         no

     e - Definition of the origin:

         NNT constraints on the daily basis for all
         VLBI stations

     f - Definition of the orientation:

         NNR constraints on the daily basis for all
         VLBI stations

     g - Reference epoch:

         1997.0

     h - Tectonic plate model:

         itrf2000 velocities used as apriori;
         exponential model for Gilcreek after the Denali, 2002
         earthquake [Titov, Tregoning; 2004]

     i - Constraints for time evolution:

         None

 7 - Earth orientation:

     a - A priori precession model:

         IERS 1996

     b - A priori nutation model:

         MHB2000

     c - Short-period tidal variations in x, y, UT1:

         Model used according to: R.Eanes (2000) as in IERS
         Conventions 2000


 8 - Estimated Parameters:

     a - Celestial Frame:

         - right ascension and declination of 571 sources as
         global parameters 
         - daily coordinates of 107 sources as
         'arc' parameters (102 'defining' source [Ma et al.; 
         1998] plus 5 additional sources as treated for the 
         ICRF-Ext.2 [Fey, et al.; 2004])


     b - Terrestrial Frame:

         Daily  x, y, z values for all sites
         with further estimation of (x0,y0,z0) referred to
         1997.0 and corresponding velocities

     c - Earth Orientation:

         xp, yp, UT1-UTC, dpsi, deps

     d - Others:

         - clock offsets, rates and 2nd derivatives;
         - wet zenith tropospheric delays;
         - wet troposphere gradients.

         Clock offsets, wet delays and gradients and EOP were
         considered as stochastic parameters with relevant
         covariance functions. IMF mapping function [Niell, 
         2001] has been applied for the troposphere modeling

    References:

Fey, A., et al., The second extension of the International 
Celestial Reference Frame: ICRF-Ext.1.  AJ, 127, 3587-3608, 
2004.  
Ma, C., et al., The International Celestial Reference 
Frame as realized by Very Long Baseline Interferometry, AJ, 116, 
516-546, 1998.
Niell, A., Preliminary evaluation of 
atmospheric mapping functions based on numerical weather models, 
Phys. Chem. Earth, 26, 475-480, 2001.
Titov & Tregoning, Post-Seismic Motion of Gilcreek Geodetic Sites 
Following the November, 2002 Denali Earthquake, in International 
VLBI Service for Geodesy and Astrometry 2004 General Meeting 
Proceedings, edited by Nancy R. Vandenberg and Karen D. Baver, 
NASA/CP-2004-212255, 2004.