Technical description of solution bkg00004.eops

1.  Purpose of solution:  Session EOP

2 - Analysis Center:  Federal Agency for Cartography and Geodesy (BKG Leipzig) and
                      Geodetic Institute of the University of Bonn

3.  Short narrative description of solution:

All available Mark III/IV sessions from 1984 were analysed for this solution except
one baseline and small network sessions which are not suitable for reliable EOP 
determination. The orientation of CRF is defined by no-net-rotation constraints
for 212 defining sources related to the ICRF-Ext.1 catalogue. The TRF is defined  
by no-net-translation and rotation constraints for the coordinates and velocities 
of 26 sites related to ITRF2000.  

4.  Estimated parameters:

    a. celestial frame:  right ascension, declination

    b. terrestrial frame:  X, Y, Z, Xdot, Ydot, Zdot                            

    c. Earth orientation:  x, y, UT1-TAI, xdot, ydot, UT1dot, dpsi, deps

    d. zenith troposphere:  1h piece-wise linear functions,
                            rate constraint generally 50 ps/hour

    e. troposphere gradient:  east and north offset,
			      offset constraint 0.5 mm,
			      rate constraint 2.0 mm/day

    f. station clocks:  1h piece-wise linear functions,
                        rate constraint generally 5.E-14

    g. baseline clocks:  set in initial analysis - usually used

    h. other:  No

5.  Celestial reference frame:

    a. a priori source positions:  ICRF-Ext.1 

    b. source positions adjusted in solution:  Yes

    c. definition of orientation: no-net-rotation of sources with respect
       to ICRF-Ext.1 for 212 defining sources marked in the ITRF-Ext.1 catalog

6 - Terrestrial reference frame:

    a. a priori station positions:  ITRF2000                   

    b. a priori station velocities:  ITRF2000   

    c. reference epoch:  1997.0

    d. definition of origin, orientation, and their time evolution:

       no-net-translation and no-net-rotation of position with respect to
       ITRF2000 for 26 stations:

       ALGOPARK BR-VLBA  DSS45    FD-VLBA  FORTLEZA HARTRAO  HOBART26 KASHIM34
       KASHIMA  KAUAI    KOKEE    LA-VLBA  MATERA   MK-VLBA  NL-VLBA  NOTO   
       NRAO20   NRAO85_3 NYALES20 ONSALA60 RICHMOND SANTIA12 SC-VLBA  SESHAN25
       WESTFORD WETTZELL 

       no-net-translation and no-net-rotation of velocity with respect to
       ITRF2000 for the same 26 stations:

       ALGOPARK BR-VLBA  DSS45    FD-VLBA  FORTLEZA HARTRAO  HOBART26 KASHIM34
       KASHIMA  KAUAI    KOKEE    LA-VLBA  MATERA   MK-VLBA  NL-VLBA  NOTO   
       NRAO20   NRAO85_3 NYALES20 ONSALA60 RICHMOND SANTIA12 SC-VLBA  SESHAN25
       WESTFORD WETTZELL 


7.  Earth orientation:

    a. a priori precession model:  IERS 1996

    b. a priori nutation model:  IERS 1996

    c. Short-period tidal variations in x, y, UT1:
    
       Model used according to:
       John Gipson, VLBI determination of neglected tidal terms in
       high frequency Earth Orientation Variation.
       Journal of Geophysical Research, Vol. 101, No. B12, p. 28051-28064
       Dec 10, 1996

    d. EOP estimation: x, xdot, y, ydot, UT1-TAI, UT1dot, dpsi, deps each session

8.  A priori geophysical models:

    a. troposphere: hydrostatic component with NMF mapping function

    b. solid Earth tide:  IERS Conventions

    c. ocean loading:  IERS Conventions

    d. atmosphere loading:  none

9.  Data type:  Group delays

10. Data editing: 
    Editing of outliers during adjustment when necessary.

11. Data weighting:  Observations are weighted using std reported
    in observational files; re-weighting iteration for each session
    to achieve the chi-square unity.

12. Standard errors reported:  Reported formal errors are derived from
    least-squares estimation propagated from data uncertainties and 
    weighted as discussed in #11.

13  Software:  Calc 9.12, SOLVE release: 2002.10.04

14. Other information:
    Field 18 contains the session code
    Field 19 contains the duration of experiments