New combined VLBI, SLR, GPS, DORIS, and multi-technique solutions are being prepared by the Technique Services for the next update of the International Terrestrial Reference Frame (ITRF). Since the release of ITRF2005 in 2006, a great deal of work has been done to better understand inconsistencies and systematic differences in earlier technique solutions. In addition, many new models have been implemented, improved analysis strategies adopted, and long-term, consistent reprocessings undertaken. Expectations are high for a new ITRF realization that achieves the highest level of accuracy, precision, and internal consistency.
Papers are sought that examine all aspects of this process, including the generation of input technique solutions, combination methodologies, characterization and treatment of remaining systematic errors, datum specification, and future directions. Evaluations of the input solutions and test ITRF combinations are also requested.
A closely related issue is the question of how best to integrate regional and other densified network solutions into the global frame. Numerous approaches have been used over the past two decades and experience has revealed problems with some of these. We request papers exposing some of the difficulties to be avoided and recommendations on preferred strategies to achieve the highest possible accuracy and consistency.