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PRECISE DOMESTIC VLBI IN 22GHz BAND FOR GEODESY

用于大地测量的 22GHz 频段精密国内 VLBI

基本信息

批准号：
06452079
负责人：
KAWANO Nobuyuki
金额：
$ 4.54万
依托单位：
National Astronomical Observatory (NAO)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06452079/
关键词：
VLBI 22GHz VLBI FOR GEODESY CORRECTION FOR PROPAGATION DELAY S X BAND SIZE OF A RADIO SOURCE

项目摘要

VLBI in 22GHz band is a powerful technique for geodesy because of wide bandwidth, small propagation delay, possibility of the correction for tropospheric delay and small size of a radio source. However, there are some dificulties to realize VLBI in 22GHz band for geodesy such as a small number of observed sources, requirement of a high stable frequency standard and frequency distribution system, small flux density of a radio source. We developed the system required for it, and make it clear that the VLBI system has the potential to measure a baseline with an accuracy of a few cm or less.The items studied in this project are as follows, 1) development of 22GHz VLBI system with phase-stabilized opical fiber link, 2) surveying radio sources at 22GHz and selection of the radio sources for the observation, 3) domestic VLBI observations with the system, 4)estimation of the baseline. The VLBI observations were carried out on two baselines of Mizusawa-Kashima (Communications Research Laboratory) and Mizusawa-Kagoshima. The error of the delay measured on the baseline of Mizusawa-Kashima was 59ps(1.8cm in path length) in the case of integration time of 258 sec, while the error was 82ps for 160 sec in S/X band. This result suggests that 22GHz VLBI is available for geodesy with an accuracy of a few cm or less.

22 GHz波段VLBI具有带宽宽、传播延迟小、对流层延迟改正的可能性和射电源的体积小等优点，是一种强有力的大地测量技术。然而，在22 GHz波段实现VLBI测量存在着观测源数量少、要求频率标准和频率分配系统稳定性高、射电源通量密度小等困难。本课题的研究内容包括：（1）22 GHz VLBI系统的研制;（2）22 GHz射电源的测量及观测射电源的选择;（3）22 GHz VLBI系统的设计与实现;（4）22 GHz VLBI系统的设计与实现;（5）22 GHz VLBI系统的设计与实现;（6）22 GHz VLBI系统的设计与实现; 3）国内VLBI观测; 4）基线估算。VLBI观测在Mizusawa-Kashima（通信研究实验室）和Mizusawa-Kagoshima两条基线上进行。在Mizusawa-Kashima基线上，积分时间为258秒时，延迟测量误差为59 ps（光程长为1.8cm），而在S/X波段，积分时间为160秒时，延迟测量误差为82 ps。这一结果表明，22 GHz VLBI可用于精度为几厘米或更小的大地测量。