A statistical selection of on-plate sites based on a VLBI global solution

Abstract

In the compilation of the conventional terrestrial reference frame with modern space geodetic techniques, one of the important issues is to select those on-plate sites. Considering that whether the motion of a site can be modeled or not by plate rigid motion is not necessarily dependant on the distance from the site to the plate boundary or deforming zones, we propose a statistical selection of on-plate sites. By applying this selection method on a VLBI global solution, the followings are shown. (1) The statistically selected on-plate sites are more than and in consistency globally with the VLBI primary sites of the International Terrestrial Reference Frame 2000 (ITRF2000). (2) The statistical selection emphasizes the consistency between the site motion and the plate rigid motion but ignores the distance from the site to the plate boundaries or deforming zones. (3) Some of the statistically selected on-plate sites are not primaries in ITRF2000. However, by including these sites the estimations of plate rigid motion are not changed significantly. Instead, the precision of estimated parameters is increased due to the improvement in the site geometric distribution. (4) Details of our analysis show that RICHMOND can be taken as a on-plate site, but it is not in the list of those most firmly on-plate. This site is usually used as one of the velocity constraint sites in VLBI global analysis. We recommend using ALGOPARK, FD-VLBA or NRAO 140 as substitutes.