U.S.-Japan Cooperative Research: Study of the Earth's Variable Rotation, and Terrestrial and Celestial Reference Frames Based on Japan-U.S. Cooperative VLBI Observations

该奖项将使美国国家大地测量研究与发展实验室的William E. Carter博士和他的研究小组能够在两年的时间内与日本水泽国际纬度观测站的Koichi Yokoyama博士和同事进行合作。他们将研究北美和欧洲甚长基线干涉测量（VLBI）网络与日本和北美VLBI网络互连的相关问题。将对两个系统使用的软件进行合理化，进行联合测试观察，并进行特别观察，以确定最佳采样频率。本研究的目的是促进这些大陆尺度VLBI网络的互连，从而大大提高大地测量的精度。VLBI是监测地球极地运动、进动和张动变化最有力的方法，它可以将间隔较宽的射电望远镜同时观测到的数据进行关联，以达到一毫秒弧以内的角精度和一厘米以内的地面距离参考。观测将由美国和日本的团队在各自的VLBI网络上进行，原始数据将由美国团队处理。研究结果将发表在联合研究论文中。

This award will enable Dr. William E. Carter, of the Geodetic Research and Development Laboratory of the U.S. National Geodetic Survey, and his research group, to collaborate with Dr. Koichi Yokoyama and co-workers of the International Latitude Observatory of Mizusawa, Japan, over a period of two years. They will work on problems related to the interconnection of the North America and Europe Very Long Baseline Interferometry (VLBI) network with the Japan and North America VLBI network. Software used by the two systems will be rationalized, joint test observing sessions will be conducted, and special observing sessions will be conducted to ascertain optimum sampling frequencies. The purpose of this research is to facilitate the interconnection of these continent-scale VLBI networks, thus greatly enhancing the precision of geodetic measurements. VLBI, in which simultaneous observations taken by widely-spaced radio telescopes can be correlated to achieve angular precision under a millisecond of arc and terrestrial distance references to within a centimeter, is the most powerful method of monitoring variations in the earth's polar motion, precession, and nutation. Observations will be taken by both the U.S. and Japanese teams on their respective VLBI networks, and the raw data will be processed by the U.S. team. The results will be presented in joint research papers.