spu00001.eops.txt

 Technical description of solution spu00001

 1.  Purpose of solution:  Session EOP

 2.  Analysis Center:  Saint-Petersburg University (SPU)

 3.  Short narrative description of solution:

 Observational VLBI time delays (IRIS-A and NEOS-A) since
 07-Feb-1983 have been analyzed for this solution. Reductional
 model is realised in accordance with IERS Conventions (1996),
 latest IERS Recommendations - IERS Gazettes 16,18 and Explanatory
 Supplement to IERS Conventions 1996 (DGFI Report, No.71).
 Relativistic corrections are from IERS Conventions (1992).
 Secular polar motion for pole tide correction given by formulae
 from Explanatory Supplement to the IERS Conventions (DGFI Report, No.71).
 Celestial reference frame was fixed to Reference Frame Navy 1997-8.
 All parameters under estimation have been adjusted using Kalman filter
 technique. Station Wettzell is used as clock reference station when
 available on default. Terrestrial reference frame ITRF97 with
 the associated velocity field is used for station coordinates.

 4.  Estimated parameters:

     a. celestial frame:  No

     b. terrestrial frame:  No

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

     d. zenith troposphere:  Random walk process

     e. troposphere gradient:  No

     f. station clocks:  Offset as a random walk process, rate as a constant

     g. baseline clocks:  No

     h. other:  No

 5.  Celestial reference frame:

     a. a priori source positions:  ICRF

     b. source positions adjusted in solution:  No

     e. solution identification or reference:  REFERENCE FRAME Navy 1997-8

 6 - Terrestrial reference frame:

     a. a priori station positions:  ITRF97

     b. a priori station velocities:  ITRF97 velocity field

     c. reference epoch:  1997.0

     d. station positions/velocities adjusted in solution:  No

     l. solution identification or reference:  ITRF97

 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:
        Gipson's model (JGR, 1996)

     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 1996 plus Explanatory
        Supplement for pole tide correction.

     c. ocean loading:  IERS Conventions 1996

     d. atmosphere loading: information about local pressure has been used
        (see IERS Conventions 1996 plus Explanatory Supplement)

 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 15 degrees to be divided by
     sin(elevation).  Observations with elevation more than 15 
     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 v. 3.4 plus additional modifications

 14. Other information:

 ------------------------------------------------------------------------------
 Dr. Oleg A.Titov                        Tel:     +7-(812)-328-97-51
 Assistant professor
 of Astronomy Department                 Fax:     +7-(812)-428-71-29

 Astronomical Institute of Saint-Peterburg University
 Bibliotechnaya sq., 2, Petrodvorets, Saint-Petersburg, Russia, 198504
 olegtitov@mail.ru