The VTRF results from the accumulation of the station coordinates from the combined normal equations of any 24h session since 1984 of nine IVS analysis centers.
The VTRF is a quarterly product of the IVS combination centre which aims to provide the most possible up-to-date station coordinate to the user. The VTRF is meant to contain station positions and velocities of new stations and stations which underwent displacements as soon as enough observations have been performed in order to allow a reliable estimation of its (new) station position. The VTRF has the objective to fill the gap between the ITRF released by publishing a new version four times a year.
A quality control of the estimated station coordinates and its associated velocities is
carried out w.r.t. the ITRF. Plots and tables with the residual differences in position and
velocity are available as well as the applied transformation parameters for all available VTRF.
Furthermore, the VTRF can be downloaded directly from the website.
An interactive tool allows to enable and disable every station and to recomputed the transformation parameter with the selected stations.