A long‐range and high‐resolution underwater acoustic positioning system     

Tomoyoshi Takeuchi 《Marine Geodesy》2013,36(3-4):225-231

Abstract

It is desired to track the location of an underwater data collecting platform using acoustic range data. A long‐range and high‐resolution acoustic system for underwater locating has been investigated. The system provides continuous and highly accurate tracking of a platform referenced to bottom‐mounted buoys. Each reference buoy contains an acoustic transponder, which is used to obtain ranging data from the transponder to the platform. The transponder has a signal source that is phase‐modulated by a maximal‐length binary sequence and a correlation processing unit to be capable of detecting received acoustic signals with high SNR in a noisy environment or in attenuation due to long‐range propagation, and to identify multipath acoustic signals. The acoustic system has been designed and sea tests tried. The results of that experiment have yielded capability of a submeter underwater acoustic positioning system.  相似文献   

Hydroacoustic noise precursors of the 1990 eruption of Kelut Volcano, Indonesia     

J. Vandemeulebrouck  J. -C. Sabroux  M. Halbwachs  Surono  N. Poussielgue  J. Grangeon  J. Tabbagh   《Journal of Volcanology and Geothermal Research》2000,97(1-4)

The results of a hydroacoustic monitoring experiment in the Kelut Crater lake, Indonesia, prior to its 1990 eruption, are presented, with the benefit of hindsight. Indeed, the underwater noise levels in three widely separated frequency bands, together with the lake water temperature, was radio-transmitted and almost continuously recorded from a period of quiescence of the volcano till the onset of its 10 February 1990, eruption, which destroyed the monitoring buoy. The comparative analysis of the noise variations in the three bands, together with seismic and temperature data, have shed light on the mechanisms underlying the pre-eruptive activity. The three acoustic levels had shown conspicuous, yet distinctive, changes prior to the eruption. Acoustic level in the low-frequency (1–50 Hz) band, which increased one year before the resumption of seismic activity and the lake warming up, is interpreted as the result of boiling at depth. The source of high-acoustic level in the audiometric (500–5000 Hz) range is clearly the bubbling of volcanic gases, occurring as a strong convective column in the middle of the lake. From the variations of this audiometric level, we have estimated that the degassing rate in the lake increased by a hundred-fold during the pre-eruptive period. Variations of ultrasonic (20–100 kHz) frequency acoustic level seem to be related with pressure and thermal changes within the hydrothermal system and its rock matrix beneath the lake. In conclusion, this experiment demonstrates the potential of hydroacoustic monitoring as an early warning system at crater lake volcanoes.  相似文献   

Estimation of a widow rockfish (Sebastes entomelas) shoal off British Columbia, Canada as a joint exercise between stock assessment staff and the fishing industry     

Stanley  R. D.; Kieser  R.; Cooke  K.; Surry  A. M.; Mose  B. 《ICES Journal of Marine Science》2000,57(4):1035-1049

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Diel vertical migration and interaction of zooplankton and juvenile walleye pollock (Theragra chalcogramma) at a frontal region near the Pribilof Islands, Bering Sea   总被引：1，自引：0，他引：1  

Schabetsberger  R.; Brodeur  R. D.; Ciannelli  L.; Napp  J. M.; Swartzman  G. L. 《ICES Journal of Marine Science》2000,57(4):1283-1295

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In situ acoustic target-strength measurement of bigeye (Thunnus obesus) and yellowfin tuna (Thunnus albacares) by coupling split-beam echosounder observations and sonic tracking   总被引：2，自引：0，他引：2  

Bertrand  A.; Josse  E.; Masse  J. 《ICES Journal of Marine Science》1999,56(1):51-60

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闽江口水下三角洲的形成与演变 Ⅱ．水下三角洲平原   总被引：2，自引：2，他引：0  

陈峰  张培辉等 《台湾海峡》1999,18(1):1-5

闽江口水下三角洲的形成与演变全文从分析控制或影响闽江口水下三角洲发育的环境因素、入手,探讨了闽江口水下三角洲的地貌特征、成因及演变。研究结果表明,闽江口水下三角洲属于构造－潮控型三角洲,其地貌特征和成因与典型的潮成三角洲既有共同点,也存在着较大的差异。此外,其近期地貌的发育和演变亦受到人类工程活动的重大影响。这些结论可为闽江口航道综合整治工程提供科学理论依据。本文为其第二部分,主要探讨闽江口水下三角洲平原的地貌特征及演变。  相似文献   

Target strength of southern blue whiting (Micromesistius australis) using swimbladder modelling, split beam and deconvolution     

McClatchie  Sam; Macaulay  Gavin; Hanchet  Stuart; Coombs  Roger F. 《ICES Journal of Marine Science》1998,55(3):482-493

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全姿态水下移动平台模式切换姿态控制研究          下载免费PDF全文

林锐  曹军军  刘纯虎  连琏 《海洋技术学报》2023,(4):1-13

为了适应复杂海洋环境中多样性的观探测任务需求,本文提出了一种融合Argo浮标、水下滑翔机（Glider）和自治式水下机器人（Autonomous Underwater Vehicle,AUV） 3种工作模式的全姿态水下移动平台（All-attitude Multimode Underwater Vehicle,AMUV）。首先,基于3种水下移动平台的工作原理,建立了AMUV的六自由度动力学模型;然后,针对动力学模型中的非线性耦合特性及模式切换过程中的驱动位形变化等问题,基于比例、积分、微分控制器（Proportional Integral Derivative,PID）与模糊控制概念,设计了不依赖于数学模型的自适应模糊PID姿态控制器,实现了AMUV多模式切换过程中的姿态控制;最后,开展多模式切换控制仿真实验,将自适应模糊PID控制器与传统PID控制器仿真结果进行对比,并设计了全模式任务工况,仿真结果表明,本文提出的控制器能够精确和稳定地控制AMUV进行多种工作模式的相互切换。  相似文献   

水下机器人标准体系框架构建探索          下载免费PDF全文

郭小勇  汤海荣  徐春红 《海洋开发与管理》2021,38(1):53-56

水下机器人作为一类特种机器人,日益成为探索海洋奥秘、开发海洋资源的重要工具,被称为海洋高技术的皇冠,正逐步成为国家间海洋技术竞争的制高点。水下机器人标准体系最直接的作用是指导、规范水下机器人标准制定工作,使人们清楚水下机器人标准化工作方向和重点,有助于推动水下机器人研发和产业化进程,促进快速、健康发展。文章在介绍国内外水下机器人标准制订的基础上,探讨水下机器人标准体系框架构建思路,提出标准体系建设路径,明确水下机器人标准化工作范围和领域,并构建了水下机器人标准体系序列结构、三维结构、层次结构3种框架模型,为构建我国水下机器人标准体系提供了有价值的参考。  相似文献   

基于垂直面阵水下定位的算法研究     

徐寿志  程鹏飞  蔡艳辉  李为乔 《全球定位系统》2010,35(2):9-13

当前的DGPS水下立体定位是基于水面上的基线面阵双曲线定位系统,对于信号接收器位于同一个垂直平面内时并没有给出具体的定位模型。利用垂直面阵上信号接收机的几何关系自定义坐标系,通过测边网解算方法计算出它们在所定义的坐标系中的坐标。水下声源发射器发射信号,经过一段时间后,各信号接收器接收到信号,利用示波器和信号处理技术得到各信号接收器接收时刻的时间差。通过建立距离交汇模式的定位模型,解算出水下声源发射器的三维坐标。结合在湖北清江的多目标水声信号识别与检测试验,根据实际测得的相关数据解算出水下目标发射器的坐标。由于此定位方法不需要GPS精密时钟,节约了定位成本。适合船体携带,操作方便。为水下目标定位提供了一个新的方法。  相似文献