Study of atmospheric phase fluctuations using three-element very-long-baseline interferometry
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants |
Applied physics, general
|Research Institution||Kagoshima University |
MIYAZAKI Tomoyuki Kagoshima Univ., Faculty of Engineering, Professor, 工学部, 教授 (80037241)
NISHIO Masanori Kagoshima Univ., Faculty of Science, Associate Professor, 理学部, 助教授 (70135383)
KAWANO Nobuyuki National Astronomical Obs., National Institutes of Natural Sciences, Professor, 電波研究部, 教授 (10186116)
YASUDA Shigeru Kagoshima Univ., Faculty of Engineering, Research Associate, 工学部, 助手 (30253909)
|Project Period (FY)
2004 – 2005
Completed (Fiscal Year 2005)
|Budget Amount *help
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥2,700,000 (Direct Cost: ¥2,700,000)
|Keywords||very-long-baseline interferometry / radio-wave propagation / atmospheric phase fluctuations / geostationar satellite / beacon wave / weather observation|
Three-element very-long-baseline interferometry (VLBI) of atmospheric phase fluctuations was made by using 12 GHz beacon signals from a geostationary satellite to obtain the following results :
1.The profiles of the Allan standard deviation and the temporal structure function for atmospheric phase fluctuations from 1 s to 2000 s were similar with those previously reported.
2.It was experimentally confirmed that the Allan standard deviation and the temporal structure function of the atmospheric phase fluctuations at the individual observation site were derived from the observed three-element VLBI data using a method proposed our previous article.
3.The magnitude and profiles of the Allan standard deviation and the temporal structure function for the individual observation site showed time variations during the observations. The enhancement of the Allan standard deviations was closely correlated with a rapid development of low pressure system.
4.The Enhancement of the Allan standard deviatio
n occurred at almost all the ranges of time intervals depending on the weather condition. This result was different from that obtained using a space VLBI satellites‘HALCA', where the enhancement was seen only at the time interval from 10 to 100 s.
5.Time intervals corresponding to break point of the temporal structure functions for the individual observation site varied with time, and the time variations correlated with the wind velocity at lower troposphere.
Simultaneous VLBI of atmospheric phase fluctuations at 12 GHz and 19 GHz was made using two geostationary satellites, and the following results were obtained :
6.Strong component of phase fluctuations of 1400 s, which were detected in our previous observation at 19 GHz, were not found in this observation. On the contrary, a component of phase fluctuations of 600 s was occasionally detected.
7.Although directions of two satellites emitting 12GHz and 19GHz beacons were separated about 25 degrees, the patters of the phase fluctuations at two different frequencies were well similar to each other. This result implies that the atmospheric phase fluctuations have correlations even for the separation larger than 10 degrees, which was given as maximum separation in previous studies.
These results are published in nine papers. In addition, two patent has been submitted and one patent has been obtained based on results of the present project and related studies. Less
Report (3 results)
Research Products (26 results)