****************************************************************************** dorismail 06-Apr-2021 14:01:11 Message No 1268 ****************************************************************************** Author: Xavier Collilieux Subject: IAG 2021 scientific assembly: session 1.1 Dear Colleagues We would like to draw your attention to the "International Terrestrial Refe= rence Frame: strengths, weaknesses and strategies for future improvements" = session (1.1) of the next scientific assembly of the International Associat= ion of Geodesy virtual meeting (June 28-July 2, 2021). Please consider subm= itting an abstract to this session. Please see http://www.iag2021.com/en/we= b/index/1646_140108__ for this and other Symposium 1 sessions. Abstract submission deadline: *30th April, 2021* (http://www.iag2021.com/e= n/web/index/1646_802946__). We are looking forward to your contributions. With apologies for cross-post= ings. Best regards, Xavier Collilieux, Ryan Hippenstiel, Zhiping Lu, Anthony M=E9min ****** Session 1.1: International Terrestrial Reference Frame: strengths, weakness= es and strategies for future improvements ****** The Terrestrial Reference Frame is fundamental for monitoring Earth rotatio= n in space and for all geoscience applications that require absolute positi= oning and precise orbit determination of artificial satellites. The Interna= tional Terrestrial Reference Frame (ITRF) series are determined using geode= tic data from Doppler Orbitography and Radiopositioning Integrated by Satel= lite (DORIS), Global Navigation Satellite Systems (GNSS), Satellite Laser R= anging (SLR) and Very Long Baseline Interferometry (VLBI). Their overall ac= curacy depends on data modeling strategies, on the precision of the relativ= e position of geodetic instruments at co-location sites (local tie survey) = and on the combination strategy in the final data adjustment. A new release of the International Terrestrial Reference Frame, namelyITRF2= 020, is currently under preparation. The objective of this session is to di= scuss any advancement that could lead to an improvement of the next Terrest= rial Reference Frames in terms of accuracy of the frame parameters and stat= ion coordinates. The following topics are of specific importance: * Recent space geodetic data modeling updatesand mitigation of technique sy= stematic errors. * New local tie determination and challenges. * Impact of nonlinear stationmotions (loading effects, post-seismic deforma= tion, etc.) and their modeling on the terrestrial reference frame. * Combination strategies for the ITRF determination. Keywords: International Terrestrial Reference Frame (ITRF), DORIS, GNSS, SL= R, VLBI, multi-technique combination, frame estimation, local ties, secular= /non-secular station motions, GIA, loading effects