0 - Technical description of solution iaa2019a.trf

 1 - Technique:   VLBI

 2 - Analysis Centre:
       IAA
     
 3 - Software used:
       QUASAR
     
 4 - Data span:
     Aug 1979 - Jan 2019, 
	 11,107,906  group delays, 5815 sessions 

 5 - Celestial Reference Frame:  ICRF2

     a - Nature:
     
         extragalactic

     b - Definition of the orientation:
         no-net-rotation using 295 defining sources of the ICRF2.

 6 - Terrestrial Reference Frame: ITRF2014 and associated 
                                  ITRF2014 velocity field 
                                  
        
      Definition of the origin:
     
         No net translation condition for 21 stations in the TRF
         (WETTZELL, NYALES20, WESTFORD, KOKEE  , ONSALA60,
		  MATERA  , LA-VLBA , FD-VLBA , OV-VLBA, KP-VLBA ,
		  BR-VLBA , FORTLEZA, NL-VLBA , KATH12M, YARRA12M,
		  SVETLOE , HN-VLBA , HOBART12, SC-VLBA, HARTRAO ,
          BADARY   )

	 i.e. sum over all translations of these stations is zero.

      Definition of the orientation:
     
         No net rotation condition for 21 stations in the TRF
         (WETTZELL, NYALES20, WESTFORD, KOKEE  , ONSALA60,
		  MATERA  , LA-VLBA , FD-VLBA , OV-VLBA, KP-VLBA ,
		  BR-VLBA , FORTLEZA, NL-VLBA , KATH12M, YARRA12M,
		  SVETLOE , HN-VLBA , HOBART12, SC-VLBA, HARTRAO ,
          BADARY   )
	 i.e. sum over all rotations of these stations is zero.

       Reference epoch:
     
         2010.0

     Constraints for time evolution:
     
         No net velocity adjustment condition in translation 
         and rotation for 21 stations in the TRF 
         (WETTZELL, NYALES20, WESTFORD, KOKEE  , ONSALA60,
		  MATERA  , LA-VLBA , FD-VLBA , OV-VLBA, KP-VLBA ,
		  BR-VLBA , FORTLEZA, NL-VLBA , KATH12M, YARRA12M,
		  SVETLOE , HN-VLBA , HOBART12, SC-VLBA, HARTRAO ,
          BADARY   )
        i.e. sum over all velocities adjustments in translation 
         and rotation of these stations TRF is zero.
         
     VLBI antenna axis offsets:      
     
       The values of VLBI antenna axis offsets were taken from official IVS list.


 7 - Earth orientation:

     a - A priori precession model:
     
	IAU 2000A Precession-Nutation Model
         
     b - A priori nutation model:
     
	IAU 2000A Precession-Nutation Model

     c - Short-period tidal variations in x, y, UT1:

    IERS Conventions 2003 model

 8 - Estimated Parameters:

    a. celestial frame: right ascension, declination (global)
 
    b. terrestrial frame:  X, Y, Z, Xdot, Ydot, Zdot (global)
 
    c. Earth orientation: Xp, Yp, UT1-TAI, Xc, Yc (local)
 
    d. zenith troposphere:   linear + stochastic signal (local).
 
    e. troposphere gradient: east and north (local)
 
    f. station clocks: quadratic (local) + stochastic signal (local).