aus00002.eops.txt

 Technical description of solution aus00002

 1. Purpose of solution:  Session EOP

 2. Analysis Center: GEOSCIENCE AUSTRALIA (AUS)

 3. Short narrative description of solution:

 Observational VLBI time delays ( IRIS-A/NEOS-A) since 07-Feb-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 Geoscience Australia solution 2002
 (ga2002a).  Terrestrial reference frame - daily station
 coordinates have been estimated under NNR and NNT constraints.
 All stations for 24-hour session are used for the constraints exception
 the TIGOCONC VLBI site. Associated velocity field is used for station
 coordinates calculation.  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, 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:  ga2002a ICRF solution

     b. source positions adjusted in solution:  No

     e. solution identification or reference:  ga2002a

 6 - Terrestrial reference frame:

     a. a priori station positions:  ga2002a ITRF solution exception
                                     TIGOCONC, SVETLOE and GILCREEK after
                                     03-Nov-2003

     b. a priori station velocities:  ga2002a ITRF solution exception
                                      TIGOCONC, SVETLOE and GILCREEK
                                      after 03-Nov-2003

     c. reference epoch:  1997.0

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

     l. solution identification or reference:  ga2002a

 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   every
                         session

 8.  A priori geophysical models:

     a. troposphere: Niell 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 applied

 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 5.1

 14. Other information:

   For new station TIGOCONC in Chile the following apriori
   coordinates for initial epoch 1997.0 have been adopted
   The stations is not used for NNT and NNR constraints.

   X =  1492054.032 m
   Y = -4887960.972 m
   Z = -3803541.438 m

   For new station SVETLOE in Russia the following apriori
   coordinates for initial epoch 1997.0 have been adopted.

   X =  2370173.964 m
   Y =  1562442.580 m
   Z =  5529969.035 m

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

   dX = -36 mm
   dY = -58 mm
   dZ = -37 mm

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


 ----------------------------------------------------------------------
 Dr. Oleg A.Titov                        Tel:     +61-2-62499064
 Project officer                         Fax:     +61-2-62499929

 Geoscience Australia
 PO Box 378, Canberra, ACT, 26102, Australia

 e-mail: Oleg.Titov@ga.gov.au