Download or read book Matched field Processing for Underwater Acoustics written by Alexandra Tolstoy and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Underwater Acoustics and Ocean Dynamics written by Lisheng Zhou and published by Springer. This book was released on 2016-10-17 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.
Download or read book Acoustic Signal Processing for Ocean Exploration written by J.M.F Moura and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic Signal Processing for Ocean Explortion has two major goals: (i) to present signal processing algorithms that take into account the models of acoustic propagation in the ocean and; (ii) to give a perspective of the broad set of techniques, problems, and applications arising in ocean exploration. The book discusses related issues and problems focused in model based acoustic signal processing methods. Besides addressing the problem of the propagation of acoustics in the ocean, it presents relevant acoustic signal processing methods like matched field processing, array processing, and localization and detection techniques. These more traditional contexts are herein enlarged to include imaging and mapping, and new signal representation models like time/frequency and wavelet transforms. Several applied aspects of these topics, such as the application of acoustics to fisheries, sea floor swath mapping by swath bathymetry and side scan sonar, autonomous underwater vehicles and communications in underwater are also considered.
Download or read book Underwater Acoustic Data Processing written by Y. T. Chan and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the papers that were accepted for presentation at the 1988 NATO Advanced Study Institute on Underwater Acoustic Data Processing, held at the Royal Military College of Canada from 18 to 29 July, 1988. Approximately 110 participants from various NATO countries were in attendance during this two week period. Their research interests range from underwater acoustics to signal processing and computer science; some are renowned scientists and some are recent Ph.D. graduates. The purpose of the ASI was to provide an authoritative summing up of the various research activities related to sonar technology. The exposition on each subject began with one or two tutorials prepared by invited lecturers, followed by research papers which provided indications of the state of development in that specific area. I have broadly classified the papers into three sections under the titles of I. Propagation and Noise, II. Signal Processing and III. Post Processing. The reader will find in Section I papers on low frequency acoustic sources and effects of the medium on underwater acoustic propagation. Problems such as coherence loss due to boundary interaction, wavefront distortion and multipath transmission were addressed. Besides the medium, corrupting noise sources also have a strong influence on the performance of a sonar system and several researchers described methods of modeling these sources.
Download or read book Model Based Processing for Underwater Acoustic Arrays written by Edmund J. Sullivan and published by Springer. This book was released on 2015-05-14 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents a unified approach to model-based processing for underwater acoustic arrays. The use of physical models in passive array processing is not a new idea, but it has been used on a case-by-case basis, and as such, lacks any unifying structure. This work views all such processing methods as estimation procedures, which then can be unified by treating them all as a form of joint estimation based on a Kalman-type recursive processor, which can be recursive either in space or time, depending on the application. This is done for three reasons. First, the Kalman filter provides a natural framework for the inclusion of physical models in a processing scheme. Second, it allows poorly known model parameters to be jointly estimated along with the quantities of interest. This is important, since in certain areas of array processing already in use, such as those based on matched-field processing, the so-called mismatch problem either degrades performance or, indeed, prevents any solution at all. Thirdly, such a unification provides a formal means of quantifying the performance improvement. The term model-based will be strictly defined as the use of physics-based models as a means of introducing a priori information. This leads naturally to viewing the method as a Bayesian processor. Short expositions of estimation theory and acoustic array theory are presented, followed by a presentation of the Kalman filter in its recursive estimator form. Examples of applications to localization, bearing estimation, range estimation and model parameter estimation are provided along with experimental results verifying the method. The book is sufficiently self-contained to serve as a guide for the application of model-based array processing for the practicing engineer.
Download or read book Inverse Problems in Underwater Acoustics written by Michael I. Taroudakis and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides recent and useful results for bottom recognition, inverse scattering in acoustic wave guides and ocean acoustic tomography, plus a discussion of some of the new algorithms, such as those related to matched-field processing, which have recently been used for inverting experimental data.
Download or read book Important Elements In Geoacoustic Inversion Signal Processing and Reverberation in Underwater Acoustics written by Alex Tolstoy and published by . This book was released on 2008-01-01 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a number of papers by leading researchers discussing their work on either geoacoustic inversion (GI), signal processing (SP), or reverberation. It is intended for scientists entering these fields as well as for experienced researchers. Chapter 1 (Tolstoy) begins the section on GI. It is a review article covering the main topics of GI and mentions such subjects as matched field processing (MFP), improved source localization and tracking, array element localization, propagation and parameter modeling, search methods, the nature of the search spaces, improving efficiency, sensitivities and uncertainty, benchmarking, and applications to simulated and test data. It is intended as a resource for understanding the GI area as well as for locating key references. Chapter 2 (Dosso) describes one of the most successful and most applied methods for GI: a Bayesian approach using a hybrid simulated annealing (SA) variant for optimization and Gibbs sampling to characterize the posterior probability density. The formulation is discussed here in mathematical detail. The emphasis in this chapter is on rigorous uncertainty estimation where the unknowns are considered to be random variables constrained by the data and prior information. Errors are assumed to be Gaussian distributed for the derivation of some key equations, and statistical tests are presented to support this assumption. Data from the PROSIM 97 experiment at numerous frequencies are analyzed. Chapter 3 (Chapman & Jiang) discusses the interpretation of matched field inversion results, particularly their limitations, and illustrates their analysis using multifrequency experimental data from the New Jersey continental shelf site that was selected on the basis of high spatial and temporal coherence across the array. They are concerned with the impact of data errors due to parameter correlations in Bayesian inversions, and the effect of the bottom slope in three dimensions (they conclude that only two dimensions are needed for their inversions). Chapter 4 (Michalopoulou & Nolte) begins as a review of Bayesian source localization methods but is primarily concerned with one such approach which the authors developed: the Optimum Uncertain Field Processor (OUFP). This is an approach used for target localization and tracking which reduces sensitivity to environmental mismatch by incorporating prior information. The method also produces posterior distributions permitting the quantification of uncertainty and error estimation of calculated parameters including environmental properties. Moving and multiple sources are discussed. Chapter 5 (Taroudakis) discusses modal inversion techniques in shallow water. Modal observables such as modal phase, modal arrivals, and dispersion curves using both the time and frequency domains are incorporated into linear and non-linear inversion procedures. The methods are based on geophysical analysis using normal mode propagation. Good separation of modes is required which is affected by the nature of the array and the frequencies used for the inversions in a given scenario. Chapter 6 (Baxley) is a review of the use of GI primarily to: (1) show results of simplified approaches to GI, (2) review the SWellEX experiments of 1993-1999 as a good testbed of GI, and (3) perform inversion using horizontal as well as vertical line arrays. The intention was the optimization of system performance for the localization and tracking of undersea targets using a variety of arrays and the Bartlett processor. Range-independence was assumed so that a simple normal mode model could be used. A number of parameters were estimated using a number of frequencies (less than 200Hz) assuming a simplified bottom. Chapter 7 (Rajan et al.) is a complete and mathematical discussion of modal inverse techniques. The chapter presents a formulation of the inverse problem, an estimation of the modal eigenvalue, demonstrations in RI and RD waveguides with discussions of error sources, spectral estimation, modal attenuation coefficients, sediment characteristics determined from modal dispersion data, integral equations, matrix inversion, resolution and variation of estimates, further demonstrations of inversion success for simulated and test data, and more. A complete coverage of modal issues is presented here. Chapter 8 (Tolstoy) is the final chapter on GI and concerns a volumetric (tomographic) GI method. This approach combines individual 2-D (range and depth slice) inversions on multiple arrays and for distributed sources into a full consistent 3-D (range, depth, and azimuth) image of the region bottom. It is discussed within the context of the Haro Strait test and concludes that information about array geometry (phone depths and shape) is essential for successful inversion where success is defined as high MFP values (at any and all frequencies with good signal-to-noise) at a unique set of parameters. Additionally, 3-D resolution may be improved via regularization to counter scarcity of resources. Chapter 9 (Arvelo) starts the section on signal processing with a detailed discussion of the factors affecting system performance, particularly at low frequencies (below 1 kHz). These include noise, especially as it affects coherence (temporal and spatial), waveguide variability (such as bathymetry), and scattering processes. A review of low-frequency coherence modeling and measurements is presented, and examples are provided to illustrate key points. Methods to circumvent the hard limits imposed by spatial coherence include the exploitation of multiple dimensions, such as the design of planar and volumetric arrays. Seismic coherence is also discussed. Chapter 10 (Sullivan & Candy) is a review of passive synthetic aperture processing (PASA). This approach to array processing utilizes the (towed) array motion to enhance its performance by explicitly incorporating this motion into the signal model. Historically, its name is based on the idea that the improved performance is equivalent to effectively having a longer array (the array appears to be larger when multiple phone locations can be combined coherently, and this approach is most effective for short aperture arrays). It is unique in that it treats the problem as a recursive estimation process rather than a beamforming process. Again, the primary interest here is system performance. Since it recursive in time, its application is limited to continuous signals (such as radiated noise) as opposed to short-term signals (such as pulses). The authors present the PASA development in mathematical detail (narrowband and broadband, single and multiple sources) including both simulated and experimental data. Chapter 11 (Zurk) completes the section on signal processing where concerns about waveguide mismatch are addressed by the development of more robust processing methods. Rather than attempting to determine ocean properties, many signal processors concentrate on the goal of devising techniques less dependent on the channel nature with the intent of improving system performance in uncertain environments. This can involve incorporating the statistics of the environment, using a calibration source, or developing invariant (robust) processors. These approaches are discussed here. Chapter 12 (Gauss) is the only chapter to concentrate on reverberation and presents a review of active sonar components coupled with signal processing for the purpose of detecting, localizing, and tracking undersea targets. Incomplete knowledge of the environment and clutter (reverberation from non-targets) are the primary limits on system performance. Clutter mechanisms include: bathymetry, the ocean surface roughness, fish, bubbles, and more. These mechanisms and methods to control their influence using frequencies 50 Hz to 5 kHz (single frequency and broadband), in deep and shallow water scenarios, are discussed. Deconvolution is critical to all reverberation efforts. Additionally, Doppler effects can be also used to separate signal contributions. The chapter concludes with a summary of contemporary issues and future trends. Finally, the observant reader will notice that this text is dedicated to Leon Sibul. Leon died quite unexpectedly early in 2007 with the intention of contributing a chapter to this book. We in the research community miss his mathematical insights and contributions to signal processing. We miss the chapter he would have given to us in this book. But most of all, we miss him.
Download or read book Underwater Acoustic Modeling written by P.C. Etter and published by CRC Press. This book was released on 1995-11-30 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling provides the only comprehensive source on how to translate our physical understanding of sound in the sea into mathematical formulas solvable by computers.
Download or read book Underwater Acoustic Signal Processing written by Douglas A. Abraham and published by Springer. This book was released on 2019-02-14 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides comprehensive coverage of the detection and processing of signals in underwater acoustics. Background material on active and passive sonar systems, underwater acoustics, and statistical signal processing makes the book a self-contained and valuable resource for graduate students, researchers, and active practitioners alike. Signal detection topics span a range of common signal types including signals of known form such as active sonar or communications signals; signals of unknown form, including passive sonar and narrowband signals; and transient signals such as marine mammal vocalizations. This text, along with its companion volume on beamforming, provides a thorough treatment of underwater acoustic signal processing that speaks to its author’s broad experience in the field.
Download or read book High resolution Spatial Processing in Underwater Acoustics written by Ronald A. Wagstaff and published by . This book was released on 1985 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Ocean Acoustic Tomography Using Matched Field Processing written by Frédéric M. Strohm and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Matched Field Processing Based Geo acoustic Inversion in Shallow Water written by Lin Wan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Shallow water acoustics is one of the most challenging areas of underwater acoustics; it deals with strong sea bottom and surface interactions, multipath propagation, and it often involves complex variability in the water column. The sea bottom is the dominant environmental influence in shallow water. An accurate solution to the Helmholtz equation in a shallow water waveguide requires accurate seabed acoustic parameters (including seabed sound speed and attenuation) to define the bottom boundary condition. Direct measurement of these bottom acoustic parameters is excessively time consuming, expensive, and spatially limited. Thus, inverted geo-acoustic parameters from acoustic field measurements are desirable.
Download or read book Computational Ocean Acoustics written by Finn B. Jensen and published by Springer Science & Business Media. This book was released on 2011-06-10 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt: Senior level/graduate level text/reference presenting state-of-the- art numerical techniques to solve the wave equation in heterogeneous fluid-solid media. Numerical models have become standard research tools in acoustic laboratories, and thus computational acoustics is becoming an increasingly important branch of ocean acoustic science. The first edition of this successful book, written by the recognized leaders of the field, was the first to present a comprehensive and modern introduction to computational ocean acoustics accessible to students. This revision, with 100 additional pages, completely updates the material in the first edition and includes new models based on current research. It includes problems and solutions in every chapter, making the book more useful in teaching (the first edition had a separate solutions manual). The book is intended for graduate and advanced undergraduate students of acoustics, geology and geophysics, applied mathematics, ocean engineering or as a reference in computational methods courses, as well as professionals in these fields, particularly those working in government (especially Navy) and industry labs engaged in the development or use of propagating models.
Download or read book Springer Handbook of Acoustics written by Thomas Rossing and published by Springer Science & Business Media. This book was released on 2007-06-21 with total page 1179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an unparalleled modern handbook reflecting the richly interdisciplinary nature of acoustics edited by an acknowledged master in the field. The handbook reviews the most important areas of the subject, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest research and applications are incorporated throughout, including computer recognition and synthesis of speech, physiological acoustics, diagnostic imaging and therapeutic applications and acoustical oceanography. An accompanying CD-ROM contains audio and video files.
Download or read book Underwater Acoustic Modelling and Simulation Third Edition written by P.C. Etter and published by CRC Press. This book was released on 2003-12-08 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling and Simulation examines the translation of our physical understanding of sound in the sea into mathematical models that can simulate acoustic propagation, noise and reverberation in the ocean. These models are used in a variety of research and operational applications to predict and diagnose the performance of complex sonar systems operating in the undersea environment. Previous editions of the book have provided invaluable guidance to sonar technologists, acoustical oceanographers and applied mathematicians in the selection and application of underwater acoustic models. Now that simulation is fast becoming an accurate, efficient and economical alternative to field-testing and at-sea training, this new edition will also provide useful guidance to systems engineers and operations analysts interested in simulating sonar performance. Guidelines for selecting and using available propagation, noise and reverberation models are highlighted. Specific examples of each type of model are discussed to illustrate model formulations, assumptions and algorithm efficiency. Instructive case studies demonstrate applications in sonar simulation.
Download or read book Full Field Inversion Methods in Ocean and Seismo Acoustics written by Orest Diachok and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in the power of inversion methods, the accuracy of acoustic field prediction codes, and the speed of digital computers have made the full field inversion of ocean and seismic parameters on a large scale a practical possibility. These methods exploit amplitude and phase information detected on hydrophone/geophone arrays, thereby extending traditional inversion schemes based on time of flight measurements. Full field inversion methods provide environmental information by minimising the mismatch between measured and predicted acoustic fields through a global search of possible environmental parameters. Full Field Inversion Methods in Ocean and Seismo-Acoustics is the formal record of a conference held in Italy in June 1994, sponsored by NATO SACLANT Undersea Research Centre. It includes papers by NATO specialists and others. Topics covered include: · speed and accuracy of acoustic field prediction codes · signal processing strategies · global inversion algorithms · search spaces of environmental parameters · environmental stochastic limitations · special purpose computer architectures · measurement geometries · source and receiving sensor technologies.
Download or read book Applied Underwater Acoustics written by Thomas Neighbors and published by Elsevier. This book was released on 2017-01-19 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied Underwater Acoustics meets the needs of scientists and engineers working in underwater acoustics and graduate students solving problems in, and preparing theses on, topics in underwater acoustics. The book is structured to provide the basis for rapidly assimilating the essential underwater acoustic knowledge base for practical application to daily research and analysis. Each chapter of the book is self-supporting and focuses on a single topic and its relation to underwater acoustics. The chapters start with a brief description of the topic's physical background, necessary definitions, and a short description of the applications, along with a roadmap to the chapter. The subtopics covered within individual subchapters include most frequently used equations that describe the topic. Equations are not derived, rather, assumptions behind equations and limitations on the applications of each equation are emphasized. Figures, tables, and illustrations related to the sub-topic are presented in an easy-to-use manner, and examples on the use of the equations, including appropriate figures and tables are also included. - Provides a complete and up-to-date treatment of all major subjects of underwater acoustics - Presents chapters written by recognized experts in their individual field - Covers the fundamental knowledge scientists and engineers need to solve problems in underwater acoustics - Illuminates, in shorter sub-chapters, the modern applications of underwater acoustics that are described in worked examples - Demands no prior knowledge of underwater acoustics, and the physical principles and mathematics are designed to be readily understood by scientists, engineers, and graduate students of underwater acoustics - Includes a comprehensive list of literature references for each chapter
