On July 15, Xu Ye, the researcher from Nanjing Purple Mountain Observatory visited NTSC on invitation for academic exchange, and gave an academic report titled as “VLBI High-precision Astrometry”. The symposium was presided by Cai Hongbing, the associate researcher of Time-keeping Theory and Method Dept. and more than 20 researchers and postgraduates attended the symposium.

In the report, Xu Ye introduced the measuring principle, recent development, error sources and scientific application of VLBI, had a heated discussion with the scientific research personnel of CAS, gave beneficial suggestions for VLBI Station construction of CAS, and expressed a willingness to cooperate with CAS researchers for VLBI observational studies of pulsar.