From the first installation to the year 2007, FReDNet has acquired a database 5 years long; this great database allows to elaborate with hight reliability and precision the data that has been acquired. The elaboration and the calculation of coordinates and velocities of geodetic deformation has been accomplished by the software GAMIT/GLOBK; the coordinates and velocities are converted from the International reference frame ITRF00 to the European reference frame ETRF00(ETRS89) refered to the actual epoch. After, by means of ITRF00 velocities, they are translated in the European reference frame ETRF00 (ETRS89) from the actual epoch to the 1989.0 epoch.
Where:
- X is the vector of the cartesian coordinates (x, y, z).
- V is the vector of velocities (Vx, Vy, Vz).
- T is the vector of translation of the euro-asian region in comparison to the ITRF.
- R is the matrix of rotation of the euro-asian region in comparison to the ITRF.
Mind that the ITRF00 is a International teference frame, instead the ETRF is a European system built in the year 1989 and it is fixed with the translation motion of the euro-asian region (about 3cm/yr toward NE).
The values of the vector T and the matrix R are the following (Boucher e Altamimi, 2001):
T = [ 0.0540 0.0510 -0.0480 ]
R = [ 0 0.7920 0.4900; -0.7920 0 -0.0810; -0.4900 0.0810 0 ]
For the calculation of the stations coordinates refered to th 1989.0 epoch and recently installed (with a no longer availability) has been adopted the following way:
- Estimation of 7 parameter from reference frame ITRF00 to reference frame ETRS89 for known values stations:
The parameters calculated are:- t vector of traslation (3 parameters).
- R matrx of rotation (3 parameters).
- k factor scale (1 parameter).
- Calculation of the vector of position v for the new station in the reference frame ITRF00
- v vector of position
- Calculation of the vector of position v for the new station through a roto-traslation
U = t + R*v
