New trends for the realization of the International Terrestrial Reference System

With the advent of Space geodesy techniques in early eighties, global terrestrial reference frames became available whose precision is still improving parallel to measuring and modeling advances. As a global reference, the realization of the International Terrestrial Reference System (ITRS), known as the International Terrestrial Reference Frame (ITRF), maintained by the International Earth Rotation Service, has sustained substantial improvement and enhancement. One of the major new trends is the 2000 ITRS realization, to be considered as a standard solution for a wide user community (geodesy, geophysics, astronomy, etc.). The ITRF2000 comprises on one hand primary core stations observed by VLBI, LLR, GPS, SLR and DORIS techniques and, on the other hand, significant extension provided by regional GPS networks for densifications as well as other useful geodetic markers tied to space geodetic ones. The ITRF2000 combination and implementation strategy are described in this paper. Important results in terms of datum definition as well as quality assessment of the ITRF2000 are presented. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.