DEVELOPMENT OF AN INTERFACE SYSTEM TO ENSURE COMPATIBLITY OF THE EXITING VARIOUS VLBI RECORDING SYSTEMS FOR GLOBAL GEODETIC OBSERVATIONS

开发接口系统以确保现有各种 VLBI 记录系统与全球大地测量观测的兼容性

• 批准号: 07404022
• 负责人: YOKOYAMA Koichi
• 金额: $ 2.5万
• 依托单位: NATIONAL ASTRONOMICAL OBSERVATORY,JAPAN
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07404022/
• 关键词: Very Long Baseline Interferometry; Global VLBI Network; Geodynamics; 超長基線電波千渉法(VLBI)

BackgroundVery Long Baseline Interferometry (VLBI), which was brought into regular operation in early 1980's, has made a number of remarkable scientific accomplishment in the field of geodynamics. They are, first detection of the contemporary plate motions and motions along the plate boundaries, insight of the earth's core by means of nutation, polar motion and earth's variable rotation, precise understanding of angular momentum exchange of solid earth, atmosphere and oceans, establishment of the astronomical reference frame based on precise positioning of extra-galactic radio sources, establishment of terrestrial reference frame based on precise determination of the station coordinates and motions, etc.However, due to the advent of GPS (Global Positioning System), the role of terrestrial reference system has been gradually taken over by GPS.Hence it is the time for VLBI to clearly define its future scientific targets for the next decade. This will be certainly realized by establishing … More a high-accuracy global VLBI networks for continuous monitoring of the earth's rotation.On the other hand, according to the history of VLBI system development made in various countries, the exiting recording systems are mutually incompatible. For example, Japanese VLBI community has developed K-4 recording system whose recording format is different from that of US developed and preceding Mark-III system. Also Canadian VLBI community has developed S2 system which has different recording format compared to the Japanese and US systems. This situation has made it difficult to make a concerting global VLBI observation for geodynamic research.AccomplishmentsAs the geotic VLBI group of the National Astronomical Observatory, Japan (NAOJ) has only K-4 system, we have been unable of participating global VLBI observations. In order to resolve the problem, we have made effort to deploy K-4 recording system to overseas antenna sites. By the end of the 1995 academic year, we deployed our system to the Urumqi Astronomical Observatory of China and the Crimean Astrophysical Observatory of Ukraine and initiated K-4 global observations.However, VLBI activities of NAOJ is still restricted to this K-4 network and cannot participate in the Mark-III VLBI networks. Hence we planned to develop an interface system which enables us to handle both K-4 and Mark-III format through this two-year research project.In this research project, we introduced a set of high density digital tape recorder (DR-101B,made by INTERFEROMETRICS), and developed and installed an interface circuit which is possible to read and write both K-4 and Mark-III formats. This has successfully been accomplished and at present we can operate a network composed of two different recording systems.Future PlanDuring the term of our research project, NASA announced the plan of forming Mark-IV VLBI global networks for continuous 24-hour observations, which is composed of seven networks. Mark-IV recorder is an up-graded version of Mark-III and has a bit rate of 0.5Gb/s. In order to join the NASA Mark-IV network, we still have to grade up our newly developed interface system. Also NAOJ is collaborating with the National Institute for Polar Research to conduct geodetic VLBI observations at the Antarctic Syowa station from the next year. In this project, we are planning to make joint observations with Australian VLBI community. The presently used VLBI system of Australia is Canadian S2 system. Hence we need to develop another interface to make compatibility with S2 system. Thus we are planning to extend our research project to make compatibility among K-4, Mark-IV and S2 systems. This system called 'Multi-Format System' will be completed during1997 to 1998 academic year. Less

背景甚长基线干涉测量（VLBI）自80年代初投入使用以来，在地球动力学领域取得了一系列令人瞩目的科学成就。它们是：首次探测到现代板块运动和沿沿着板块边界的运动，利用章动、极移和地球自转的变化了解地核，精确了解固体地球、大气和海洋的角动量交换，建立以河外射电源精确定位为基础的天文参考架，在精确确定台站坐标和运动等的基础上建立地面参考框架，然而，由于GPS的出现，（全球定位系统），随着全球定位系统（GPS）逐渐取代地球参考系的地位，VLBI应明确未来10年的科学目标。这将通过建立 ...更多信息 另一方面，从各国VLBI系统发展的历史来看，现有的VLBI观测系统互不兼容。例如，日本VLBI界已经开发了K-4记录系统，其记录格式不同于美国开发的和以前的Mark-III系统。加拿大VLBI界也开发了S2系统，与日本和美国的系统相比，它具有不同的记录格式。由于日本国家天文台（NAOJ）的地球VLBI观测组只有K-4系统，我们无法参加全球VLBI观测。为了解决这一问题，我们努力在海外天线站点部署K-4记录系统。到1995学年末，我们在中国乌鲁木齐天文台和乌克兰克里米亚天体物理观测站部署了VLBI系统，开始了K-4全球观测，但我国国家天文台的VLBI活动仍局限于该K-4网，不能参加Mark-III VLBI网。因此，本研究计划通过两年的研究，开发出能够同时处理K-4和Mark-Ⅲ格式的接口系统。在本研究中，我们引进了一台高密度数字磁带录音机（Interferometrics公司的DR-101 B），开发并安装了能够读写K-4和Mark-Ⅲ格式的接口电路。未来的计划在我们的研究项目期间，NASA宣布了建立Mark-IV VLBI全球观测网的计划，该观测网由7个观测网组成，可进行24小时连续观测。Mark-IV记录器是Mark-III的升级版本，具有0.5Gb/s的比特率。为了加入NASA Mark-IV网络，我们仍然需要升级我们新开发的接口系统。日本国家天文台还与国家极地研究所合作，从明年起在南极Syowa站进行大地测量VLBI观测。在这个项目中，我们计划与澳大利亚VLBI团体进行联合观测。澳大利亚目前使用的VLBI系统是加拿大的S2系统。因此，我们需要开发另一个接口，使与S2系统兼容。因此，我们计划扩展我们的研究项目，使K-4，Mark-IV和S2系统之间的兼容性。这个系统称为“多格式系统”，将于1997至1998学年完成。少

项目成果

横山紘一: "重力と地球回転" 月刊地球. 号外11. 20-23 (1995)

横山浩一：《重力与地球自转》月刊地球。 11. 20-23 (1995)

真鍋盛二: "VLBIの10年-地球科学への貢献" 天文月報. 88. 152-157 (1995)

Moriji Manabe：“VLBI 十年 - 对地球科学的贡献”天文月报 88. 152-157 (1995)。

Manabe S.: "10 years of VLBI-Contribution to earth science (in Japanese)." The Astronomical Herald. 88. 152-157 (1995)

Manabe S.：“VLBI 十年——对地球科学的贡献（日语）”。

Segawa,J.,I.Nakagawa,T.Tanaka,R.Shichi,T.Kato,K.Yokoyama,Y.Baba,Y.Ganeko,& Y.Okada: "The role of geodesy in the earth environmental study" J.Geod.Soc.Japan. 39. 419-424 (1995)

濑川，J.，I.Nakakawa，T.Tanaka，R.Shichi，T.Kato，K.Yokoyama，Y.Baba，Y.Ganeko，

真鍋盛二: "VERAによる地球回転パラメータ決定精度" 1995年度VLBIシンポジウム(1996年1月24日〜26日). 60-62 (1996)

Moriji Manabe：“使用 VERA 确定地球自转参数的精度”1995 年 VLBI 研讨会（1996 年 1 月 24-26 日）60-62 (1996)。