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Establishment of the Trans-Pacific VLBI Network for Monitoring the Earth's Variable Rotation

建立跨太平洋地球自转监测VLBI网络

基本信息

批准号：
62420003
负责人：
YOKOYAMA Koichi
金额：
$ 6.21万
依托单位：
National Astronomical Observatory (1988)緯度観測所 (1987)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

1. Objectives of the Research: (1) To achieve high-precision measurement of the Earth's variable rotation. (2) To achieve high-precision time synchronization between Kashima (Japan) and Richmond (Florida, USA). (3) To conduct data analysis and improve data analysis software. (4) To establish the management system to smoothly operate the Trans-Atrantic VLBI network (IRIS-P).2. Cooperative Institutes: Although the research group consists solely of the National Astronomical Observatory staff, this research was carried out in close cooperation with two institutes, namely the Communications Research Laboratory (CRL, Japan) and the National Geodetic Survey (NGS, USA). CRL offered the use of K-3 VLBI system at Kashima, and NGS offered the arrangement of the US stations participation in IRIS-P network, as well as correlation of observed video tapes at the correlation center in the United States Naval Observatory.3. Research Plans: (1) 1987: To initiate the IRSI-P network composed of Kashima of … More CRL (Japan). Richmond (Florida, USA), Ft. Davis (Texas, USA), and Fairbanks (Alaska, USA) and operate it smoothly as the network center for acquiring the data which meet the reseatch objectives, and to conduct data analysis and compare the results with those of CRL and NGS. (2) 1988: To improve observation schedule based on the results derived from 1987 observations, and to refine analysis software.4. Research Activities: (1) Observation: Monthly 24-hour session observations were completely made as scheduled, by sending 3 observers to Kashima every time. (2) Network Operation: Within half a year from the initiation of the network, the system was established to shipping tapes to and from the correlation center and to send observation schedules to the participating stations through an electronic mail. (3) Data Analysis and Software Improvement: With the aid of CRL cooperation, the results obtained by our software were carefully examined and thereby necessary improvement was made. In June 1988, S. Manabe of the research group visited NGS to discuss matters on data analysis. Eventually, the presently used software has sufficient capability for data analysis as the network center of IRIS-P.5. Scientific Findings: (1) We determined the Earth's rotation with the precision better than 1 cm. Thus the IRIS-P network is the best among existing three VLBI networks. (2) We found errors of the positions of extragalactic quasars of the order of a few milli-arcseconds. (3) We tied the positions of the participating stations with the global terretrial reference system with the precision of a few cm. (4) We achieved time synchronization between Kashima and Richmond with the precision of 0.5 ns. Less

1. 研究目标： (1) 实现地球自转的高精度测量。（2）实现日本鹿岛和美国佛罗里达州里士满之间的高精度时间同步。（3）进行数据分析，完善数据分析软件。（4）建立跨大西洋VLBI网络（IRIS-P）顺利运行的管理体系。2．合作机构：虽然研究小组仅由国家天文台工作人员组成，但这项研究是与两个机构密切合作进行的，即通信研究实验室（CRL，日本）和国家大地测量局（NGS，美国）。 CRL提供了鹿岛K-3 VLBI系统的使用，NGS提供了美国台站参与IRIS-P网络的安排，以及美国海军天文台相关中心观测录像带的相关性。 3．研究计划： (1) 1987 年：启动由 CRL（日本）Kashima 组成的 IRSI-P 网络。里士满（美国佛罗里达州），英尺。戴维斯（美国德克萨斯州）和费尔班克斯（美国阿拉斯加州）作为网络中心顺利运行，获取符合研究目标的数据，并进行数据分析并与CRL和NGS的结果进行比较。 (2)1988年：在1987年观测结果的基础上完善观测计划，完善分析软件。4．研究活动：（1）观察：每月24小时会议观察完全按计划进行，每次派3名观察员前往鹿岛。（2）网络运行：网络开通后半年内，建立了系统，可将磁带往返于相关中心，并通过电子邮件向参与站发送观测时间表。（3）数据分析和软件改进：在CRL的配合下，我们对软件得到的结果进行了仔细的检查，从而进行了必要的改进。 1988年6月，课题组S.Manabe访问NGS，讨论数据分析事宜。最终，目前使用的软件已经具备了足够的数据分析能力，可以作为IRIS-P.5的网络中心。科学发现：（1）我们测定了地球自转，精度优于1厘米。因此IRIS-P网络是现有的三种VLBI网络中最好的。 (2)我们发现河外类星体的位置存在几毫秒量级的误差。 (3) 我们将参与站的位置与全球地球参考系统联系起来，精度达到几厘米。 (4) 实现了鹿岛和里士满之间的时间同步，精度为0.5 ns。较少的