Matched field localization and environmental inversion from deep‐water vertical line array measurements.

2010 ◽  
Vol 128 (4) ◽  
pp. 2386-2386 ◽  
Author(s):  
Kevin D. Heaney ◽  
Richard C. Campbell ◽  
Arthur B. Baggeroer ◽  
Gerald L. D’Spain ◽  
Peter Worcester ◽  
...  
Keyword(s):  
Deep Water ◽  
Vertical Line ◽  
Array Measurements ◽  
Line Array ◽  
Field Localization ◽  
Matched Field Localization

scholarly journals Joint Estimation of Source Range and Depth Using a Bottom-Deployed Vertical Line Array in Deep Water

Sensors ◽  
2017 ◽  
Vol 17 (6) ◽  
pp. 1315 ◽  
Author(s):  
Hui Li ◽  
Kunde Yang ◽  
Rui Duan ◽  
Zhixiong Lei
Keyword(s):  
Deep Water ◽  
Joint Estimation ◽  
Vertical Line ◽  
Line Array

Vertical line array measurements of the sound radiated by melting glaciers in Hornsund Fjord

2020 ◽  
Vol 148 (4) ◽  
pp. 2483-2483
Author(s):  
Hari Vishnu ◽  
Mandar Chitre ◽  
Oskar Glowacki ◽  
Mateusz Moskalik ◽  
M. Dale Stokes ◽  
...  
Keyword(s):  
Vertical Line ◽  
Array Measurements ◽  
Line Array

scholarly journals Vertical line array measurements of ambient noise in the North Pacific

2017 ◽  
Vol 141 (3) ◽  
pp. 1571-1581 ◽  
Author(s):  
Mehdi Farrokhrooz ◽  
Kathleen E. Wage ◽  
Matthew A. Dzieciuch ◽  
Peter F. Worcester
Keyword(s):  
North Pacific ◽  
Ambient Noise ◽  
Vertical Line ◽  
The North ◽  
Array Measurements ◽  
Line Array ◽  
The North Pacific

Flow Noise Spectrum Analysis for Vertical Line Array During Descent in Deep Water

2020 ◽  
Vol 28 (04) ◽  
pp. 2050022
Author(s):  
Chunlong Huang ◽  
Hui Li ◽  
Nansong Li
Keyword(s):  
Source Localization ◽  
Deep Water ◽  
Spectrum Analysis ◽  
Sound Propagation ◽  
Vertical Line ◽  
High Signal ◽  
Stream Velocity ◽  
Low Frequencies ◽  
Flow Noise ◽  
Line Array

Reliable acoustic path (RAP) is a direct path used for sound propagation between a shallow source and a deep receiver in deep water. The RAP environment can provide a high signal-to-noise ratio (SNR) environment for source localization, so it has been widely studied for underwater passive detection. Active detection can be used for source localization during the descent of a vertical line array (VLA). However, the flow noise originating from the pressure fluctuations in the turbulent boundary layer (TBL) during the descent degrades the detection performance of the VLA. This paper presents a calculation of the response of the cylindrical hydrophones to axisymmetric turbulent wall pressure and the physical properties of flow noise. The flow noise was calculated using the wavenumber-frequency spectrum analysis method, which is based on Carpenter’s TBL pressure spectrum. The results show that the energy of the flow noise is concentrated mainly in low frequencies and it increases and spreads toward high frequencies with increasing stream velocity. The conclusions have been verified with experimental data. In addition, the noise correlation between two hydrophones will undergo oscillatory decay as the hydrophone spacing increases. The above findings will be beneficial for signal processing of an active sonar array.

scholarly journals Reliable Acoustic Path and Direct-Arrival Zone Spatial Gain Analysis for a Vertical Line Array

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3462 ◽  
Author(s):  
Chunyu Qiu ◽  
Shuqing Ma ◽  
Yu Chen ◽  
Zhou Meng ◽  
Jianfei Wang
Keyword(s):  
Sound Propagation ◽  
Correlation Coefficients ◽  
Deep Ocean ◽  
Vertical Line ◽  
Horizontal Line ◽  
Acoustic Path ◽  
Vertical Arrays ◽  
Peak Structure ◽  
Line Array ◽  
Propagation Properties

A method is developed in this paper to calculate the spatial gain of a vertical line array when the plane-wave assumption is not applicable and when the oceanic ambient noise is correlated. The proposed optimal array gain (OAG), which can evaluate the array’s performance and effectively guide its deployment, can be given by an equation in which the noise gain (NG) is subtracted from the signal gain (SG); hence, a high SG and a negative NG can enhance the performance of the array. OAGs and SGs with different array locations are simulated and analyzed based on the sound propagation properties of the direct-arrival zone (DAZ) and the reliable acoustic path (RAP) using ray theory. SG and NG are related to the correlation coefficients of the signals and noise, respectively, and the vertical correlation is determined by the structures of the multipath arrivals. The SG in the DAZ is always high because there is little difference between the multipath waves, while the SG in the RAP changes with the source-receiver range because of the variety of structure in the multiple arrivals. The SG under different conditions is simulated in this work. The “dual peak” structure can often be observed in the vertical directionality pattern of the noise because of the presence of bottom reflection and deep sound channel. When the directions of the signal and noise are close, the conventional beamformer will enhance the correlation of not only the signals but also the noise; thus, the directivity of the signals and noise are analyzed. Under the condition of having a typical sound speed profile, the OAG in some areas of the DAZ and RAP can achieve high values and even exceed the ideal gain of horizontal line array 10 logN dB, while, in some other areas, it will be lowered because of the influence of the NG. The proposed method of gain analysis can provide analysis methods for vertical arrays in the deep ocean under many conditions with references. The theory and simulation are tested by experimental data.

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