scholarly journals Experimental Results for Direction of Arrival Estimation with a Single Acoustic Vector Sensor in Shallow Water

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Alper Bereketli ◽  
Mehmet B. Guldogan ◽  
Taner Kolcak ◽  
Tamer Gudu ◽  
Ahmet Levent Avsar
Keyword(s):  
Shallow Water ◽  
Time Domain ◽  
Three Dimensional ◽  
Direction Of Arrival ◽  
Experimental Results ◽  
Computationally Efficient ◽  
Acoustic Source ◽  
Acoustic Vector Sensor ◽  
Vector Sensor ◽  
Almost All

We study the performances of several computationally efficient and simple techniques for estimating direction of arrival (DOA) of an underwater acoustic source using a single acoustic vector sensor (AVS) in shallow water. Underwater AVS is a compact device, which consists of one hydrophone and three accelerometers in a packaged form, measuring scalar pressure and three-dimensional acceleration simultaneously at a single position. A very controlled experimental setup is prepared to test how well-known techniques, namely, arctan-based, intensity-based, time domain beamforming, and frequency domain beamforming methods, perform in estimating DOA of a source in different circumstances. Experimental results reveal that for almost all cases beamforming techniques perform best. Moreover, arctan-based method, which is the simplest of all, provides satisfactory results for practical purposes.

Estimation of Direction of Arrival of Biological Sound using Acoustic Vector Sensor Array in Shallow Water off Chennai

2020 ◽  
Vol 89 (sp1) ◽  
pp. 52
Author(s):  
Madan Mohan Mahanty ◽  
Ganeshan Latha ◽  
Pedinta Sesha Sai Ramanujan Sridhar ◽  
Govindan Raguraman
Keyword(s):  
Shallow Water ◽  
Sensor Array ◽  
Direction Of Arrival ◽  
Acoustic Vector Sensor ◽  
Vector Sensor ◽  
Vector Sensor Array

A Quasi-three-dimensional Finite-volume Shallow Water Model for Green Water on Deck

2013 ◽  
Vol 57 (03) ◽  
pp. 125-140
Author(s):  
Daniel A. Liut ◽  
Kenneth M. Weems ◽  
Tin-Guen Yen
Keyword(s):  
Shallow Water ◽  
Finite Volume ◽  
Time Domain ◽  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Green Water ◽  
Water Model ◽  
Ship Motions ◽  
Shallow Water Model

A quasi-three-dimensional hydrodynamic model is presented to simulate shallow water phenomena. The method is based on a finite-volume approach designed to solve shallow water equations in the time domain. The nonlinearities of the governing equations are considered. The methodology can be used to compute green water effects on a variety of platforms with six-degrees-of-freedom motions. Different boundary and initial conditions can be applied for multiple types of moving platforms, like a ship's deck, tanks, etc. Comparisons with experimental data are discussed. The shallow water model has been integrated with the Large Amplitude Motions Program to compute the effects of green water flow over decks within a time-domain simulation of ship motions in waves. Results associated to this implementation are presented.

scholarly journals Frequency Invariant Beamforming for a Small-Sized Bi-Cone Acoustic Vector–Sensor Array

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 661
Author(s):  
Erzheng Fang ◽  
Chenyang Gui ◽  
Desen Yang ◽  
Zhongrui Zhu
Keyword(s):  
Sensor Array ◽  
Three Dimensional ◽  
Sensor Arrays ◽  
Signal Frequency ◽  
Acoustic Vector Sensor ◽  
Mechanical Coupling ◽  
Vector Sensor ◽  
Coupling System ◽  
Simulation Results ◽  
Vector Sensor Array

In this work, we design a small-sized bi-cone acoustic vector-sensor array (BCAVSA) and propose a frequency invariant beamforming method for the BCAVSA, inspired by the Ormia ochracea’s coupling ears and harmonic nesting. First, we design a BCAVSA using several sets of cylindrical acoustic vector-sensor arrays (AVSAs), which are used as a guide to construct the constant beamwidth beamformer. Due to the mechanical coupling system of the Ormia ochracea’s two ears, the phase and amplitude differences of acoustic signals at the bilateral tympanal membranes are magnified. To obtain a virtual BCAVSA with larger interelement distances, we then extend the coupling magnified system into the BCAVSA by deriving the expression of the coupling magnified matrix for the BCAVSA and providing the selecting method of coupled parameters for fitting the underwater signal frequency. Finally, the frequency invariant beamforming method is developed to acquire the constant beamwidth pattern in the three-dimensional plane by deriving several sets of the frequency weighted coefficients for the different cylindrical AVSAs. Simulation results show that this method achieves a narrower mainlobe width compared to the original BCAVSA. This method has lower sidelobes and a narrower mainlobe width compared to the coupling magnified bi-cone pressure sensor array.

Development of a Forging Type Rapid Prototyping System; Automation of a Free Forging and Metal Hammering Working

2005 ◽  
Vol 17 (5) ◽  
pp. 523-528 ◽  
Author(s):  
Hidetake Tanaka ◽  
◽  
Naoki Asakawa ◽  
Masatoshi Hirao ◽  
Keyword(s):  
Rapid Prototyping ◽  
Three Dimensional ◽  
Experimental Results ◽  
Model Design ◽  
Plastic Working ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Cad Cam ◽  
Almost All ◽  
Rapid Prototyping System

The forging rapid prototyping we proposed based on CAD data involves numerically controlled free forging and metal hammer working as new three-dimensional modeling. Almost all products are now designed and developed using CAD/CAM, and rapid prototyping using CAD data is also used to model design previews or mock ups. Free forging and plastic working, however, have few ways to automate the process. We developed numerical controlled free forging and metal hammer working as new modeling for rapid prototyping. Experimental results demonstrate that our proposal provides feasible three-dimensional modeling as rapid prototyping.

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