Technical description of solution ausd04it.snx

 1. Purpose:  VLBI session files in SINEX 2.0 format,
    including epoch coordinates and EOP.

 2. Analysis Center: GEOSCIENCE AUSTRALIA (AUS)

 3.  Short narrative description of solution:

 Observational VLBI data files including all networks since
 1983 have been analyzed for this solution. Reductional
 model is realised in accordance with IERS Conventions (2000)
 except recommended precession/nutation model.  Celestial
 reference frame was fixed to ICRF Ext.2 catalogue.
 The Terrestrial Reference Frame is defined by no-net-translation
 and rotation constraints for the coordinates of all sites in a
 VLBI session related to VTRF2003. The values of the official
 list of VLBI antenna axis offsets issued by the IVS Analysis
 Coordinator. All parameters under estimation have been adjusted
 using Kalman filter technique.  Tropospheric gradients have
 been considered as constant parameters.

 4.  Estimated parameters:

     a. celestial frame:  No

     b. terrestrial frame:  Yes

     c. Earth orientation:  X, Y, UT1-UTC, X-dot, Y-dot,
                            LOD, dpsi, deps

     d. zenith troposphere:  Random walk process

     e. troposphere gradients:  Estimates as a constant parameters

     f. station clocks:  Offset as a random walk process, rate as a
                constant except sessions when the clock rate is
                considered as a random walk process for separate
                stations

     g. baseline clocks:  No

     h. other:  No

 5.  Celestial reference frame:

     a. a priori source positions:  ICRF Ext.2 solution

     b. source positions adjusted in solution:  No

     e. solution identification or reference:  ICRF Ext.2

 6 - Terrestrial reference frame:

     a. a priori station positions:  VTRF2003 ITRF solution imposed
                                     by NNR, NNT constraints.


     b. a priori station velocities: VTRF2003 solution

     c. reference epoch:  1997.0

     d. station positions/velocities adjusted in solution:
        station positions adjusted on daily basis

     l. solution identification or reference:  VTRF2003

 7.  Earth orientation:

     a. a priori precession model:  IAU(1976)

     b. a priori nutation model:  IAU(1980)

     c. a priori short-period tidal variations in x, y, UT1:
            IERS Conventions (2000) - model by R.Eanes

     d. EOP estimation:  X, Y, UT1-UTC, dpsi, deps for each
                         session

 8.  A priori geophysical models:

     a. troposphere: Vienna mapping function for dry and wet delays

     b. solid Earth tide:  IERS Conventions 2000, except
                           re-instating for permanent tides.

     c. ocean loading:  IERS Conventions 2000

     d. atmosphere loading: No

 9.  Data type:  delays

 10. Data editing:  Only data with zero quality flag in NGS format are used

 11. Data weighting:
     Observations with elevation less than 5 degrees to be divided by
     sin(elevation).  Observations with elevation more than 5
     degrees are not weighted as a rule, but Kalman filter
     approach checks a quality of every observation and
     downweights it in case of bad result.

 12. Standard errors reported:  Formal errors are derived from
     Kalman filter adjustment

 13. Software:  OCCAM 6.0 development


 14. Other information:

   Gilcreek after the seismic event 03-Nov-2002 has the following shift
   for apriori coordinates.

   radial    =   8.0 mm
   latitude  = -47.8 mm
   longitude =  22.6 mm

   Moreover, exponential model has been applied for post-seismic
effect approximation