Technical description of solution bkgint09 Intensives

 1.  Purpose of solution: Intensive EOP

 2.  Analysis center: Federal Agency for Cartography and Geodesy (BKG Leipzig)

 3.  Short narrative description of solution:

All available Intensive sessions since 1999 were analysed for 
this solution (including the TSUKUBA-WETTZELL experiments since 2002).
Celestial reference frame was fixed to ICRF2.         
Terrestrial reference frame VTRF2008a and the associated velocity field 
are used for station coordinates, reference epoche is 2000.0. Only clock 
parameters, tropospheric zenith parameters and UT1 were adjusted using
least squares technique. The UTC epoch is the middle epoch for each session.
The values of the official list of VLBI antenna axis offsets issued by the
IVS Analysis Coordinator (http://vlbi.geod.uni-bonn.de/IVS-AC/Conventions/antenna-info.txt,
update 2009-03-16) were used.
Mean pole coordinates used for computation of pole tide deformation were applied
according to IERS Conventions 2003 (eq. 23a, 23b). The Vienna mapping function (VMF1) is
applied for troposphere correction modelling.
A priori short-period tidal variations in EOP were taken into account in accordance with IERS
Conventions 2003. Ocean loading model FES2004 computed by H. G. Scherneck was used.
Thermal expansion modelling developed by A. Nothnagel was used
(http://vlbi.geod.uni-bonn.de/IVS-AC/Conventions/antenna-info.txt).
The values of station eccentricities were taken from the official IVS-table ECCDAT.ecc.


 4.  Estimated parameters:

     a. Celestial frame: No

     b. Terrestrial frame: No

     c. Earth orientation: UT1-TAI 

     d. Zenith troposphere: Generally offsets for each session 

     e. Troposphere gradient: No
     
     f. Station clocks: 3h piece-wise linear functions, rate constraint 5*10E-14

     g. Baseline clocks: Not generally used as most are single baseline

     h. Other: No

 5.  Celestial reference frame:                

     a. A priori source positions: ICRF2                                  

     b. Source positions adjusted in solution: No

 6 - Terrestrial reference frame:
 
     a. a priori station positions:  VTRF2008a

     b. a priori station velocities:  VTRF2008a
                                      
     c. Reference epoch: 2000.0

 7.  Earth orientation: 

     a. a priori precession/nutation model: IAU2000A Precession-Nutation,
        IERS 2003 implementation, modified using the IAU2006
        precession model

     b. a priori short-period tidal variations in X, Y and UT1 due to short
        period tidal and nutation effects were applied as recommended in the
        IERS 2003 Conventions

     c. a priori UT1 and polar motion: usno_finals.data
        (http://gemini.gsfc.nasa.gov/solve_save/usno_finals.erp)

 8.  A priori geophysical models:
 
     a. troposphere: VMF1 mapping function (dry+wet), Saastamoinen
        zenith delay calculated using logged pressure and temperature
     
     b. solid Earth tide: IERS 2003 Conventions

     c. ocean loading: FES2004 model   

     d. pole tides: IERS 2003 Conventions

     e. Atmosphere loading: none

     f. antenna thermal deformation: IVS antenna thermal deformation model of Nothnagel 2008

     g. axis offsets:  values of the official list of VLBI antenna axis offsets issued by the
        IVS Analysis Coordinator (http://vlbi.geod.uni-bonn.de/IVS-AC/Conventions/antenna-info.txt)

 9.  Data type: Group delays

 10. Data editing: 5 deg elevation cutoff, 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 10,   SOLVE release: 2010.05.21

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

References:

Axel Nothnagel (2008) Short Note: Conventions on thermal expansion
modelling of radio telescopes for geodetic and astrometric VLBI;
Journal of Geodesy, DOI: 10.1007/s00190-008-0284-z.