Development of autonomous acoustic observation system using click sounds emitted by small cetacean and field experiments

在这项研究中，我们提出了一种先进的自主声学观测系统，使用伊洛瓦底江海豚和恒河海豚等小型齿科动物发出的咔哒声。由于人类活动导致的环境变化，这些物种濒临灭绝。了解它们的种群和水下行为对于研究它们的保存方法具有重要意义，因此我们开发了多水听器阵列系统，该系统可以利用LBL系统和SBL系统来检测它们的短声源位置并记录它们。因此，我们可以半实时地实现对海豚的三维定位。然后，通过离线分析数据，我们可以识别更详细的海豚位置和生物声纳特征，以了解它们的水下行为。在测试了针对栖息在日本沿海地区的Odontoceti物种江豚的阵列后，我们于2006年1月将其带到了印度。这次访问的目的是观察伊洛瓦底江海豚，大约是…其中有100多只生活在印度奥里萨邦的奇利卡湖。我们与德里的印度理工学院、CDA(Cilika Development Authority)和世界自然基金会印度分会合作，将阵列部署到湖上，并记录了点击数据。我们成功地实现了一些海豚的半实时轨迹。基于这一结果，世界自然基金会印度分会已同意将该系统应用于恒河海豚调查。我们对2005年12月在奥里萨邦布达巴兰加河上游发现的一只孤立的恒河海豚进行了实验。从数据中可以看出，恒河海豚具有波束极窄(12°)等特征。然后，我们于2007年2月在德里郊区纳罗拉的恒河进行了初步实验。预计我们将开发一套坚固紧凑的恒河海豚测量声学系统，适用于恶劣的河流环境。在伊洛瓦底江海豚调查方面，我们开发了一个由水基和陆基组成的长期监测的自主式实时声学系统的原型。施工和监测工作于2007年1月开始。我们得出的结论是，应该建设更多的具体天文台和通信网络基础设施，如互联网系统，以开发一个新的监测系统，可以实时连接湖底正在发生的事情和世界。较少

In this research, we proposed an advanced autonomous acoustic observation system using click sounds emitted by small Odontoceti species such as the Irrawaddy dolphin and the Ganges river dolphin. These species are endangered because of environmental change due to human activities. Understanding their population and underwater behavior is important to examine the methods to preserve them, so that we developed the multi-hydrophone array system which can detect their location of clicks source using LBL system and SBL system and record them. Thus, we can achieve dolphin's 3D-locationos in semi-real time. Then, by analyzing the data in off-line, we can identify more detailed location and bio-sonar characteristics of dolphins to know their underwater behaviorAfter testing the array targeting the finless porpoise which belongs to Odontoceti species and inhabits Japanese costal area, we brought it to India in January, 2006. Purpose of the visit is to observe the Irrawaddy dolphin, approximatel … More y 100 numbers of which inhabit in Chilika Lake in Orissa state in India. Collaborating with Indian Institute of Technology, Delhi, CDA (Cilika Development Authority) and WWF-India, we deployed the array to the Lake and recorded clicks data. We succeed in achieving some dolphins trajectories in semi-real time. Based on this result, WWF-India has agreed to apply the system to Ganges river dolphin survey. We made experiments on an isolated Ganges river dolphin which was found at the upper stream of Budhabalanga river in Orissa state in December 2005. From data, Ganges river dolphin's special characteristics such as very narrow beam pattern (12°) have been claritied. Then, we made preliminary experiments in Ganges river in February 2007, in Narora on the outskirts of Delhi. It is expected that we will develop a robust and compact acoustic system for Ganges river dolphin survey, which is suitable for the harsh river environment. In regard to Irrawaddy dolphin survey, we have developed a proto-type of autonomous real time acoustic system for a long term monitoring which consists of a water base and a land base. Construction and monitoring started in January 2007. We came up with conclusion that more concrete observatories and infrastructure for communication networks such as internet system should be constructed to develop a new monitoring system which can connect what is happening under the lake with the world in real time. Less