Improvement in the accuracy of real-time GPS/acoustic measurements using a multi-purpose moored buoy system by removal of acoustic multipath

Misae Imano, Motoyuki Kido, Yusaku Ohta, Tatsuya Fukuda, Hiroshi Ochi, Narumi Takahashi, Ryota Hino

研究成果: Conference contribution

6 被引用数 (Scopus)

抄録

A component of the multi-purpose moored buoy has been improved for the instantaneous detection of seafloor displacement and possible tsunami generation upon the occurrence of large earthquakes. Here, improvements to the acoustic ranging component of this buoy, which is a key element of on-demand GPS/acoustic (GPS/A) measurements, are demonstrated. A 1-m positioning accuracy is required in GPS/A measurements using the buoy system for the detection of the horizontal seafloor crustal deformation associated with large earthquakes. Owing to the limitation of collecting data on only a limited range of sub-surface depth from a single point located far from the optimal location, resulting from the slack mooring system, obtaining the positioning accuracy is challenging. To overcome this challenge, we developed an automatic travel-time algorithm that reliably excludes the multipath from acoustic waves. Applying the algorithm to the data from 4 months of sea trial, we revealed that the short-period repeatability of the positioning improved from 4 to 0.5 m, while the long-term repeatability improved from 8 to 4 m, which is still beyond the required accuracy of 1 m. Because acoustic ranging under sub-optimal conditions will propagate any error in the data at intermediate steps into the uncertainty of the final positioning, approaches to reduce the errors at each step must be undertaken, such as determination of the pre-defined geometry of seafloor transponders more precisely.

本文言語English
ホスト出版物のタイトルInternational Symposium on Geodesy for Earthquake and Natural Hazards (GENAH) - Proceedings of the International Symposium on Geodesy for Earthquake and Natural Hazards (GENAH)
編集者Manabu Hashimoto
出版社Springer Verlag
ページ105-113
ページ数9
ISBN(印刷版)9783319397672
DOI
出版ステータスPublished - 2017
イベントProceedings of the International Symposium on Geodesy for Earthquake and Natural Hazards, GENAH 2014 - Matsushima, Japan
継続期間: 2014 7 222014 7 26

出版物シリーズ

名前International Association of Geodesy Symposia
145
ISSN(印刷版)0939-9585

Other

OtherProceedings of the International Symposium on Geodesy for Earthquake and Natural Hazards, GENAH 2014
CountryJapan
CityMatsushima
Period14/7/2214/7/26

ASJC Scopus subject areas

  • Computers in Earth Sciences
  • Geophysics

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