Beam pattern estimation of clicks of a free-ranging Ganges river dolphin
Beam pattern estimation of clicks of a free-ranging Ganges river dolphin
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自由放养的恒河豚的点击声的波束方向图估计
DOI：
10.1109/oceans.2007.4449286
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
T. Fukuchi
中科院分区：
文献类型：
--
作者：
R. Bahl;H. Sugimatsu;J. Kojima;T. Ura;S. Behera;T. Inoue;T. Fukuchi
在印度奥里萨邦的布达巴兰加河，首次记录了自由活动的恒河海豚(Platanista Angetica)的生物声纳滴答声。用于记录的系统是一个3.2米长的阵列，由三个水听器组成一个等间距的线性SBL阵列，另两个水听器与中央水听器在垂直于阵列轴线的平面上形成一个小的SSBL三角形阵列。阵列结构部署在水平和垂直两种配置中。在每个水听器上接收到的海豚的滴答声以每个通道500 khz的速率进行采样。根据采样的短声数据，利用短声信号的视源电平之差和中心水听器与其他两个外周水听器之间的绝对夹角估计了海豚在水平面和垂直面上的声纳波束方向图。为了更准确地估计波束方向图，充分考虑了轴上点击的选择条件，因此我们提出了一种新的轴上点击判断标准。在这种方法中，我们假设海豚的波束指向中心水听器，并且它的波束方向图是对称的。然而，三个水听器对ASL的实际测量表明，外围水听器的值并不总是相同的。这表明海豚的波束并不完全指向中央水听器，因此中央水听器的ASL不是波束的真正峰值。我们提出了一种改进的波束方向图估计方法，采用内插和曲线拟合的方法来获得对恒河海豚波束方向图的改进估计。通过分析所有可用的点击，我们已经估计了海豚在水平和垂直平面上的波束模式。3分贝波束宽度在水平面上约为10度，在垂直面上约为14度。本文提出了一种新的基于内插和曲线拟合的波束方向图估计方法。
The first recordings of bio-sonar clicks of free-ranging Ganges river dolphin (Platanista gangetica) were made in Budhabalanga river in Orissa, India. The system used for recording is a 3.2 meter long array composed of three hydrophones forming an equispaced linear SBL array and another two hydrophones in conjunction with the central hydrophone forming a small SSBL triangular array in a plane perpendicular to the array axis. The array structure was deployed both in horizontal and vertical configurations. The clicks of the dolphin received on each hydrophone were sampled at a rate of 500 kHz per channel. From the sampled clicks data, the sonar transmit beam pattern of the dolphin in both horizontal and vertical plane was estimated using difference of ASL (apparent source level of the click signal) and the absolute angles of the dolphin's location between the central hydrophone and the other two peripheral hydrophones for the on-axis clicks. To estimate more accurate beam pattern, conditions for selection of on-axis clicks were well-considered, and thus we propose a new criteria for determining on-axis clicks. In this method, we assume that the dolphin's beam pointing direction is towards the central hydrophone and it's beam pattern is symmetrical. However, actual measurement of ASL from three hydrophones shows that values at the peripheral hydrophones are not always same. This suggests that the dolphin's beam is not pointing exactly towards the central hydrophone so that the central hydrophone's ASL is not the real peak value of the beam. We propose a refinement in the beam pattern estimation method using interpolation and curve fitting to obtain an improved estimate of the Ganges river dolphin's beam pattern. By analyzing all available clicks, we have estimated the dolphin's beam pattern in both horizontal and vertical plane. The 3-dB beamwidth is found to be approximately 10 degrees in horizontal plane and 14 degrees in vertical plane. In this paper, we propose the new beam pattern estimation method using interpolation and curve fitting.
自由活动的恒河豚记录的点击声的估计波束方向图和回声定位特征
DOI：
--
发表时间：
2007
期刊：
Proc.UT'07+SSC'07, Tokyo, Japan
影响因子：
--
作者：
浦環;Rajendar Bahl;杉松治美;小島淳一;井上知己;福地鉄雄;S.K.Behera;A.K.Pattnaik;Muntaz Khan;S.Kar;C.S.Kar;D.Swain
通讯作者：
D.Swain
DOI：
--
发表时间：
2006
期刊：
The Journal of the Acoustic Society of America (Proc.Fourth Joint Meeting of Acoustic Society of America and Acoustic Society of Japan) Vol.120, No.5
影响因子：
--
作者：
浦環;杉松治美;井上知己;Rajendar Bahl;小島淳一;赤松友成;S.K.Behera;A.K.Pattnaik;Muntaz Khan;S.Kar;C.S.Kar;福地鉄雄;高橋秀幸;D.Swain
通讯作者：
D.Swain