Effects of scattering by air bubbles on performance of an underwater acoustic array

2007 ◽  
Vol 121 (5) ◽  
pp. 3033-3033 ◽  
Author(s):  
Richard Lee Culver ◽  
Mario F. Trujillo
Keyword(s):  
Air Bubbles ◽  
Underwater Acoustic ◽  
Acoustic Array

scholarly journals Design of an underwater acoustic array for full ocean depth multi-beam echo sounder

2019 ◽  
Vol 283 ◽  
pp. 05002
Author(s):  
Haoqi Hao ◽  
Tiejian Xia ◽  
Min Xie
Keyword(s):  
High Reliability ◽  
Integrated Design ◽  
High Sensitivity ◽  
Underwater Acoustic ◽  
Technical Requirements ◽  
Planar Array ◽  
In Series ◽  
Stable Performance ◽  
Acoustic Array ◽  
Echo Sounder

In order to meet the technical requirements of full ocean depth multibeam echo sounder, the underwater acoustic array must have the ability of wide coverage, broadband response, high sensitivity and high reliability. This paper presents a design of underwater acoustic array based on Mills cross configuration with separate transmitting and receiving units. The arrays have modules design, hence the beamwidth of the array can be adjusted according to particular installation requirements. The working frequency band of the arrays is between 10.5kHz to 13.5kHz, and the coverage angle can cover -71.6°~71.6°. The Integrated design is used to achieve a wide-angle beam coverage of the planar array, which combines the transducer and the sound baffle together to realize a wide directivity of the array elements. The longitudinal bending transducers are designed to meet the broadband requirements for the transmitting array, which are Tonpilz transducers with flexural radiating head. On the other hand, each element of the receiving array is composed of several hydrophones, which are connected in series to achieve high sensitivity. The double-layer watertight technology is also applied in our design, ensuring stable performance and long service life.

Pitch and Depth Keeping of Moored-type Underwater Acoustic Array System

2019 ◽  
Author(s):  
Suk-Min Yoon ◽  
Chong-Moo Lee ◽  
Kihun Kim ◽  
Sung-Hoon Byun
Keyword(s):  
Underwater Acoustic ◽  
Acoustic Array

The application of compressive sensing to underwater acoustic array processing and design

2013 ◽  
Vol 134 (5) ◽  
pp. 4169-4169
Author(s):  
Jeffrey S. Rogers ◽  
Charles F. Gaumond ◽  
Geoffrey F. Edelmann
Keyword(s):  
Compressive Sensing ◽  
Array Processing ◽  
Underwater Acoustic ◽  
Acoustic Array

Construction of a Large Underwater Acoustic Array

1996 ◽  
Author(s):  
Robert F. Zueck ◽  
Ron L. Brackett ◽  
Anthony P. Smith ◽  
David R. Shields
Keyword(s):  
Underwater Acoustic ◽  
Acoustic Array

Diagonal rejection-based minimum variance distortionless response for fiber underwater acoustic array

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740065
Author(s):  
Yang Chen ◽  
Ling Zou ◽  
Bin Zhou
Keyword(s):  
Covariance Matrix ◽  
Array Signal Processing ◽  
Spatial Filter ◽  
Minimum Variance ◽  
Observation Time ◽  
Small Aperture ◽  
Underwater Acoustic ◽  
Low Snr ◽  
Minimum Variance Distortionless Response ◽  
Acoustic Array

The high mounting precision of the fiber underwater acoustic array leads to an array manifold without perturbation. Besides, the targets are either static or slowly moving in azimuth in underwater acoustic array signal processing. Therefore, the covariance matrix can be estimated accurately by prolonging the observation time. However, this processing is limited to poor bearing resolution due to small aperture, low SNR and strong interferences. In this paper, diagonal rejection (DR) technology for Minimum Variance Distortionless Response (MVDR) was developed to enhance the resolution performance. The core idea of DR is rejecting the main diagonal elements of the covariance matrix to improve the output signal to interference and noise ratio (SINR). The definition of SINR here implicitly assumes independence between the spatial filter and the received observations at which the SINR is measured. The power of noise converges on the diagonal line in the covariance matrix and then it is integrated into the output beams. With the diagonal noise rejected by a factor smaller than 1, the array weights of MVDR will concentrate on interference suppression, leading to a better resolution capability. The algorithm was theoretically proved with optimal rejecting coefficient derived under both infinite and finite snapshots scenarios. Numerical simulations were conducted with an example of a linear array with eight elements half-wavelength spaced. Both resolution and Direction-of-Arrival (DOA) performances of MVDR and DR-based MVDR (DR–MVDR) were compared under different SNR and snapshot numbers. A conclusion can be drawn that with the covariance matrix accurately estimated, DR–MVDR can provide a lower sidelobe output level and a better bearing resolution capacity than MVDR without harming the DOA performance.

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