VTRF results from the accumulation of station coordinates from the combined normal equations of any 24h session since 1984 of six IVS Analysis Centers.
The VTRF is a quarterly product of the IVS Combination Center that aims to provide the most up-to-date station coordinates possible to the user. The VTRF contains station positions and velocities of new stations and stations that underwent displacements. This occurs as soon as enough observations in order to allow a reliable estimation of its (new) station position have been performed. Through this, the VTRF fills the gap between the current ITRF by publishing a new version of the VTRF four times a year.
Quality control of the estimated station coordinates and their associated velocities is carried out with respect to 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.
The VTRF can be downloaded directly from the website.
An interactive tool allows the user to enable and disable every station, and to recompute the transformation parameters using only the selected stations.