Sound‐speed determination using matched field processing techniques

1989 ◽  
Vol 85 (S1) ◽  
pp. S18-S18 ◽  
Author(s):  
C. Karangelen ◽  
O. Diachok
Keyword(s):  
Sound Speed ◽  
Matched Field Processing ◽  
Processing Techniques

THE MATCHED FIELD PROCESSING BENCHMARK PROBLEMS

1994 ◽  
Vol 02 (03) ◽  
pp. 161-185 ◽  
Author(s):  
MICHAEL B. PORTER ◽  
A. TOLSTOY
Keyword(s):  
State Of The Art ◽  
Lessons Learned ◽  
Benchmark Problems ◽  
Naval Research ◽  
Test Problems ◽  
Acoustic Source ◽  
Matched Field Processing ◽  
True Source ◽  
Processing Techniques ◽  
Signal Processing Techniques

In matched field processing sophisticated acoustic models are combined with signal processing techniques to localize an acoustic source in the ocean. A key challenge has been to develop schemes that work not just in idealized simulations but in realistic scenarios. Additionally it has been difficult to get a sense of the relative merits of different schemes: there has been no common set of problems to test the techniques. To assess the state of the art, a workshop was held in May 1993 at the Naval Research Laboratory where both simulated and experimental data were provided to the community of users to test the algorithms. However, researchers were not given the true source location and thus exercised their algorithms blindly. We describe here the test problems and provide an overview of the results and the lessons learned.

scholarly journals Estimating the parameters of the seabed using the spatial characteristics of ocean ambient noise

2019 ◽  
Vol 283 ◽  
pp. 08004
Author(s):  
He Li ◽  
Xiniyi Guo ◽  
Li Ma ◽  
Guoli Song
Keyword(s):  
Experimental Data ◽  
Sound Speed ◽  
Critical Angle ◽  
Ambient Noise ◽  
Array Processing ◽  
Sound Field ◽  
Spatial Characteristics ◽  
Matched Field Processing ◽  
Spectrum Density ◽  
Snell Law

When solving traditional underwater problems, the boundary condition is always used to calculate the sound field. In practice, however, it is hard to get the boundary conditions of the seabed. So geoacoustics inversion is needed to acquire the parameters of the seabed. In this paper, a method estimating seabed parameters by using the spatial characteristics of ocean ambient noise is demonstrated without using matched-field processing. For the reason of the limit of the resolution of conventional beamforming (CBF), a method of synthetic array processing (SAP) is used because of some characters of cross-spectrum density matrix (CSDM). The result shows that the method of synthetic array processing enhanced the resolution of critical angle to some degree. By comparing the true bottomloss calculated by OASR, the result of traditional beamforming and the synthetic array processing, the result of synthetic array processing is closer to the true bottomloss than the result of traditional beamforming. After ensuring a range of critical angle, the sound speed of the seabed can be estimated by using Snell law. And then, an experimental data collected in Qingdao, China, 2016 is used to prove the validity of the method of synthetic array processing and estimate the local seabed parameters.

Bottom Geoacoustic Inversion by "Broadband" Matched-Field Processing

1998 ◽  
Vol 06 (01n02) ◽  
pp. 167-183 ◽  
Author(s):  
Michael I. Taroudakis ◽  
Maria G. Markaki
Keyword(s):  
Frequency Domain ◽  
Source Localization ◽  
Sound Speed ◽  
Good Accuracy ◽  
Depth Estimation ◽  
Benchmark Problems ◽  
Sediment Layer ◽  
Objective Functions ◽  
Matched Field Processing ◽  
Acoustic Data

Matched-Field Processing with a Genetic Algorithm is applied to the problem of bottom recognition with synthetic noise-free acoustic data. The data correspond to three classes of benchmark problems. Four alternative objective functions have been tested, all of them defined to be used with broadband data with either coherent or incoherent processing in the frequency domain. It has been concluded that the parameters corresponding to the sediment layer and especially the sound speed, are more accurately recovered by all means. Source localization and water depth estimation are made with good accuracy in all cases. It has also been shown that incoherent processing in the frequency domain has led to better results for the cases studied.

The Comparison of Bottom Parameter Inversion in Geoacoustic Space and in (P,Q) Space

2017 ◽  
Vol 25 (02) ◽  
pp. 1750011 ◽  
Author(s):  
Z. D. Zhao ◽  
E. C. Shang ◽  
Daniel Rouseff
Keyword(s):  
Sound Speed ◽  
Shift Parameter ◽  
Matched Field Processing ◽  
Acoustical Properties ◽  
Model Free ◽  
Parameter Inversion ◽  
Sea Bottom ◽  
Potential Possibility ◽  
Profile Estimation

The acoustical properties of the sea-bottom can be described by geoacoustic (GA) parameters or by reflective parameters: [Formula: see text] (phase shift parameter) and [Formula: see text] (absorption parameter). Both in GA space and in ([Formula: see text], [Formula: see text]) space, the parameters are difficult to measure and are instead estimated by inversion methods such as matched field inversion (MFI). In GA space, an assumed model is needed to mount the GA parameters for inverting (model dependent), while the reflective parameters ([Formula: see text], [Formula: see text] are model-free. In this paper, the efficiency and quality of matched field processing (MFP) in GA space as well as in ([Formula: see text]) space are compared and the potential possibility of bottom sound-speed-profile estimation is discussed.

scholarly journals USE OF RAY TRACING MODELING IN SHALLOW WATER ACOUSTIC SOURCE LOCALIZATION COMBINED WITH MATCHED-FIELD PROCESSING TECHNIQUES

2016 ◽  
Vol 34 (3) ◽  
Author(s):  
Vicente Barroso Junior ◽  
Orlando Camargo Rodríguez ◽  
Carlos Eduardo Parente Ribeiro ◽  
Luiz Gallisa Guimarães
Keyword(s):  
Shallow Water ◽  
Normal Mode ◽  
Source Localization ◽  
Acoustic Modeling ◽  
Acoustic Source ◽  
Propagation Models ◽  
Matched Field Processing ◽  
Acoustic Source Localization ◽  
Long Time ◽  
Processing Techniques

ABSTRACT. Underwater source localization based on acoustic modeling has been a subject of intensive research since a long time. In the case of shallow water scenarios (which are characterized by multilayered bottoms) normal-mode based acoustic propagation models are often combined with Matched-Field Processing techniques in order to provide accurate estimates of both source range and depth...Keywords: underwater acoustic modeling, ray-based models, normal mode models. RESUMO. A localização de fontes submarinas por meio de modelos de propagação acústica é um antigo problema de grande interesse científico. Em cenários deáguas rasas, que se caracterizam normalmente por fundos com complexos sistemas multicamadas, os modelos de propagação baseados na teoria de modos normais são geralmente combinados com técnicas de Processamento por Campo Casado para...Palavras-chave: modelagem ac´ustica submarina, modelos de raios, modelos de modos normais.

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