Scientific Assembly of the International Association of Geodesy (IAG 2021) was held successfully in Beijing from June 28 to July 2, 2021. It was hosted by International Association of Geodesy (IAG), organized by Chinese Society for Geodesy, Photogrammetry and Cartography (CSGPC), co-organized by 20 co-organizers, such as Chinese Academy of Surveying and Mapping (CASM), Wuhan University (WHU), Tongji University, etc. The theme of the Assembly is "Geodesy for a Sustainable Earth". It’s the first time that the Assembly has been organized as a virtual conference, providing a unique opportunity for participants from around the world to share their science, vision and culture.

Professor Li Bofeng, Professor Shen Yunzhong, Professor Wu Jicang, Professor Li Haojun, Professor Zhang Lei, Professor Chen Qiujie, Associate Professor Yang Ling, Assistant Professor Liang Hongyu and some graduate students from our college were invited to attend the event. Professor Chen Qiujie gave a lecture under the title of “Global Ocean Mass Change Estimates in 1993~2004 from LEO Gravity Field Models Determined at Tongji University”, which was selected as one of IAG2021 highlight lectures. Associate Professor Yang Ling gave a lecture under the title of “Quality Control of Outlier Detection, Identification and Adaptation in GNSS Positioning”, elaborating on the method of gross error detection and identification in GNSS positioning data processing. Assistant Professor Liang Hongyu gave a lecture under the title of “Estimation and Correction of Error Sources in MTInSAR”, introducing the estimation and correction methods of MTInSAR error sources. Doctoral student Wang Fengwei gave a lecture under the title of “Quantitative Analysis of Global Sea-Level Budget Based on GRACE, Satellite Altimetry and Argo Observations”, in which sea level changes were quantified based on GRACE gravity satellite data and altimetry data.