Technical description of dgf2010a intensive series UT1 solution
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 1.  Purpose of solution: generation of SINEX files for the intensive VLBI sessions.
 
 2.  Analysis center: DGFI (Deutsches Geodaetisches Forschungsinstitut).
 
 3.  Short narrative description of solution:
     Intensive solution dgf2010a provides unconstrained UT1 estimates from the 
     various VLBI intensive sessions.
 
 4.  Differences with respect to previous intensive solution:
     na
 
 5.  Estimated parameters:
 
     a. UT1 angle.
 
     b. Zenith wet delay offset at each station.
 
     c. Coefficients of a second order polynomial of clock function w.r.t. 
        reference clock.
 
 6.  Celestial reference frame:                  
 
     a. A priori source positions: ICRF2 [1].   
 
     b. Source positions adjusted in solution: No
 
 7.  Terrestrial reference frame:
 
     a. A priori station positions: DGFI internal VLBI TRF 08R02__5 [2].
 
     b. A priori station velocities: 08R02__5 [2].
 
     c. Reference epoch: 1997.0.
 
     d. Station positions/velocities adjusted in solution: No.
 
     j. Relativistic scale: IERS Conventions 2003 [3].
 
     k. Permanent tide correction: No.
        comment: this is not conform with the IAG resolution but common practice.
       
 8.  Earth orientation:   
 
     a. A priori Precession-Nutation: IAU2000A Precession-Nutation, IERS 
        Conventions 2003 [3] without FCN.
 
     b. A priori short-period tidal variations in x, y, dUT1 according to IERS 
        Conventions 2003 [3]. 
           
     c. EOP estimation: UT1.
 
     d. A priori UT1 and polar motion: IERS EOPC04 05-series [4].
 
 9.  A priori geophysical models:
 
     a. Troposphere: VM1 mapping function; modofied Saastamoinen zenith 
                     hydrostatic delay [3] calculated using pressure from log 
                     file; a priori mean gradients are taken from GSFC DAO [5].
 
     b. Solid Earth tide: IERS Conventions 2003 [3].
 
     c. Ocean loading: 3D ocean loading displacements computed by Scherneck 
        using FES2004 model [3; 6].
 
     d. Pole tide: IERS Conventions 2003 [3], i.e. linear trend for mean pole 
        offsets.
 
     e. Atmospheric loading: According to Petrov & Boy 2003 [7].
 
     f. Mean site gradients were taken from GSFC DAO [5]. The atmospheric gradient
        model is MacMillan 1995 [8].
 
     g. Antenna thermal deformation: According to Nothnagel 2008 [9].
 
     h. Antenna axis offsets: According to IVS [10].
 
     i. Station eccentricities: According to official IVS table [11].
 
 10. Data type: Group delays. 
 
 11. Data editing: Manual, no elevation cutoff (0 degrees).
 
 12. Data weighting. Weights are defined as follows: 1/sqrt ( f**2 + a**2 )
     where "f" is formal uncertainty of the ionosphere free linear combination
     of group delays at X- and S-band obtained by fringe fitting on the base 
     of achieved signal to noise ratio. Session-dependent parameter "a" was 
     computed for each session by an iterative procedure such that the ratio
     of the sum of squares of weighted residuals to the estimate of their 
     mathematical expectation is about unity.
 
 13. Standard errors reported: All errors derived from least-squares
     estimation propagated from the data weights and the constraints applied 
     to the troposphere, clock and EOP parameters.
     
 14. Software: OCCAM 6.1 LSM [12] and DOGS-CS [13] for proper SINEX generation.
 
 References:
 
 1. Ma, C., Arias, F., Bianco, G., Boboltz, D., Bolotin, S., Charlot, P., 
    Engelhardt, G., Fey, A., Gaume, R., Gontier, A.-M., Heinkelmann R., Jacobs, C., 
    Kurdubov, S., Lambert, S., Malkin, Z., Nothnagel, A., Petrov, L., 
    Skurikhina, E., Sokolova, J., Souchay, J., Sovers, O., Tesmer, V., Titov, O., 
    Wang, G., Zharov, V., "The Second Realization of the International Celestial 
    Reference Frame by Very Long Baseline Interferometry", IERS Technical Note; 
    No. 35, 2009.
 
 2. http://www.dgfi.badw.de/
 
 3. McCarthy, D.D. and Petit, G., "IERS Conventions (2003)", IERS Technical Note; 
    No. 32, 2004.
 
 4. http://hpiers.obspm.fr/eoppc/eop/eopc04_05/
 
 5. MacMillan, D.S. and Ma, C., "Using meteorological data assimilation models in 
    computing tropospheric delays at microwave frequencies", Phys. & Chem. Earth, 
    23(1):97--102, 1998.
 
 6. http://129.16.208.24/loading/
 
 7. Petrov, L. and Boy, J.-P., "Study of the atmospheric pressure loading signal in 
    Very Long Baseline Interferometry observations", Journ. Geophys. Res., 
    109(B03405), DOI: 10.1029/2003JB002500, 2003.
 
 8. MacMillan, D.S. "Atmospheric Gradients from Very Long Baseline Interferometry 
    Observations", Geophys. Res. Lett., 22(9):1041--1044, 1995.
  
 9. Nothnagel, A., "Short Note: Conventions on thermal expansion modelling of radio 
    telescopes for geodetic and sstrometric VLBI," Journ. Geod., DOI: 
    10.1007/s00190-008-0284-z, 2008.
 
10. http://vlbi.geod.uni-bonn.de/IVS-AC/Conventions/antenna-info.txt
 
11. http://gemini.gsfc.nasa.gov/solve_save/ECCDAT.ecc
 
12. Titov, O., Tesmer, V., Boehm, J., "OCCAM v.6.0 Software for VLBI Data 
    Analysis", ftp://ivscc.gsfc.nasa.gov/pub/general-meeting/2004/pdf/titov1.pdf
 
13. Gerstl, M., Kelm, R., Mueller, H., Ehrnsperger, W., "DOGSCS Kombination und 
    Lsung groer Gleichungssysteme", Manual VIII fr DOGS Version 4.05, Interner 
    Bericht Nr. MG/01/1995/DGFI, Deutsches Geodaetisches Forschungsinstitut, 2000.