The first step of ITRF2008 strategy is the independent computation of a long-term stacked Terrestrial Reference Frame (TRF) for each measurement technique under the assumption of linear motions. The associated EOPs are readjusted at the same time to make them consistent with their stacked TRFs. A break-wise approach is used to take into account discontinuities in the time series coming from any physical motion of the ground caused by an earthquake or a change in equipment.

The residuals of these computations, based on the standard relationship linking 2 frames, include the non-linear part of point behaviors with respect to the secular frame.
Important notice: translation, rotation and scale parameter time series have been adjusted during the processing of the long-term stacked frames. These parameters have absorbed some of the non-linear variations related to loading effects, especially in the vertical component due to the scale adjustment. As a consequence, ITRF2008 residuals do not supply total station non-linear motions as observed by the space geodetic techniques. See the discussion in section 2.3 of Collilieux et al., 2007.

Plots of residual time series are available online. Station position residual times series can be displayed as they are, or with their piecewise linear trend.

IGS (GPS)

ILRS (SLR)

IVS (VLBI)

IDS (DORIS)

• yyyy.yyyyy : epoch in decimal year.
• res : residual value in millimeter in North , East and Up component depending on the file extension (*.DN)(*.DE) and (*.DH) respectively.
• sigma: 1-sigma formal error.
• soln : solution number (see the discontinuity file).