Technical description of solution bkgd0001_dsnx

1.  Purpose of solution:  24 hour session solution for IVS time series of baseline lengths 
                          and basis solution for combination techniques

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 dual-band Mark III/IV observations from 1984 on were analysed for this 
solution. The orientation of CRF is defined by fixing of the global estimated source
coordinates RA, DEC of the BKG quarterly solution bkg2003d.crf. The TRF is defined  
by no-net-translation and rotation constraints for the coordinates of all sites in a 
VLBI session related to VTRF2003 except for SVETLOE and TIGOCONC.

4.  Estimated parameters:

    a. celestial frame:  No, except right ascension, declination for 97 sources estimated
			 as arc sources in BKG quarterly solution bkg2003d.crf

    b. terrestrial frame:  X, Y, Z                            

    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:  BKG quarterly solution bkg2003d.crf

    b. source positions adjusted in solution:  No, except used arc sources in 
					       BKG quarterly solution bkg2003d.crf

    c. definition of orientation: fixed source coordinates of the 
                                  BKG quarterly solution bkg2003d.crf

6 - Terrestrial reference frame:

    a. a priori station positions:  VTRF2003                   

    b. a priori station velocities:  VTRF2003   

    c. reference epoch:  1997.0
     
    d. station positions adjusted in solution: Yes

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

       no-net-translation and no-net-rotation of position with respect to
       VTRF2003 for all stations of the VLBI session except SVETLOE and TIGOCONC


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
       for the middle epoch of it  

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: 2003.05.15