time. He received his Ph.D. degree in 2007 from the Graduate University of the Chinese Academy of Sciences. Wenjun Wu (wuwj@ntsc.ac.cn) is a Researcher at the National Time Service Center at the Chinese Academy of Sciences in Xi'an, China, where his main research field is timekeeping. He received his Ph.D. degree in 2012 from the Graduate University of Chinese Academy of Sciences. He worked as a visiting scientist for the UTC time link calibration at BIPM from June 2014 to May 2015. Xiang Wang (wangxiang@ntsc.ac.cn) is a Research Assistant at the National Time Service Center at the Chinese Academy of Sciences in Xi'an, China, where her main research interests include high-precision time and frequency transfer. She received her M.S. degree in test and measurement methods and instruments from the Chinese Academy of Sciences in 2013. Zhe Gao (gaozhe@ntsc.ac.cn) is a Research Assistant at the National Time Service Center at the Chinese Academy of Sciences in Xi'an, China, where her interests include high-precision time and frequency transfer and link calibration. She received her M.S. degree in astrometry and astromechanics from the Chinese Academy of Sciences in 2016. Dong Guo (guodong@ntsc.ac.cn) is a Research Assistant at the National Time Service Center at the Chinese Academy of Sciences in Xi'an, China, where his main research interest is GNSS time transfer. He received his M.Sc. degree from Chang'an University in 2018. 24 IEEE Instrumentation & Measurement Magazine September 2022