Download or read book Optimal Localization of Ocean Acoustic Sources in an Uncertain Environment written by Anthony M. Richardson and published by . This book was released on 1990 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 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 Long Range Source Localization in a Deep Uncertain Ocean written by Paul J. Book and published by . This book was released on 1993 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Oceans 90 Conference Proceedings written by and published by . This book was released on 1990 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceans 97 MTS IEEE written by and published by . This book was released on 1997 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sea Surface Sound 94 Proceedings Of The Iii International Meeting On Natural Physical Processes Related To Sea Surface Sound written by Michael J Buckingham and published by World Scientific. This book was released on 1996-01-11 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding and constructively using natural sound in the ocean has become of prime importance with the shift of emphasis to protecting the environment and exercising responsible global resource management which has followed the end of the Cold War. Especially now that we realise that marine mammals and other inhabitants of the oceans are threatened by our acoustic pollution of their environment, the use of natural sound as a non-intrusive remote sensing probe has become particularly germane. This was the first meeting on the subject since the fall of Soviet-Western barriers, and the proceedings include significant work from premier researchers in the former Soviet Union. It was also the first meeting which specifically addressed the new and exciting idea of using natural sound in applications for monitoring the marine environment. The proceedings include a number of papers on various aspects of this topic. Further new work on the basic physics of sound production and propagation is also included. This volume includes leading-edge work from the foremost researchers in the field, including Bill Carey, Lawrence Crum, Nikolai Dubrovskii, David Farmer, Brian Kerman, Bill Kuperman, Michael Longuet-Higgins, Hank Medwin, Ken Melville, A Prosperetti and many others.

Download or read book Advanced Signal Processing Handbook written by Stergios Stergiopoulos and published by CRC Press. This book was released on 2017-09-08 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in digital signal processing algorithms and computer technology have combined to produce real-time systems with capabilities far beyond those of just few years ago. Nonlinear, adaptive methods for signal processing have emerged to provide better array gain performance, however, they lack the robustness of conventional algorithms. The challenge remains to develop a concept that exploits the advantages of both-a scheme that integrates these methods in practical, real-time systems. The Advanced Signal Processing Handbook helps you meet that challenge. Beyond offering an outstanding introduction to the principles and applications of advanced signal processing, it develops a generic processing structure that takes advantage of the similarities that exist among radar, sonar, and medical imaging systems and integrates conventional and nonlinear processing schemes.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Journal of the Acoustical Society of America written by Acoustical Society of America and published by . This book was released on 2006 with total page 1052 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Conference Proceedings written by and published by . This book was released on 1997 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Model based Ocean Acoustic Passive Localization written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 1999 IEEE International Conference on Acoustics Speech and Signal Processing written by and published by . This book was released on 1999 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acoustic Sources of Opportunity in the Marine Environment Applied to Source Localization and Ocean Sensing written by Christopher M. Verlinden and published by . This book was released on 2017 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlled acoustic sources have typically been used for imaging the ocean. These sources can either be used to locate objects or characterize the ocean environment. The processing involves signal extraction in the presence of ambient noise, with shipping being a major component of the latter. With the advent of the Automatic Identification System (AIS) which provides accurate locations of all large commercial vessels, these major noise sources can be converted from nuisance to beacons or sources of opportunity for the purpose of studying the ocean. The source localization method presented here is similar to traditional matched field processing, but differs in that libraries of data-derived measured replicas are used in place of modeled replicas. In order to account for differing source spectra between library and target vessels, cross-correlation functions are compared instead of comparing acoustic signals directly. The library of measured cross-correlation function replicas is extrapolated using waveguide invariant theory to fill gaps between ship tracks, fully populating the search grid with estimated replicas allowing for continuous tracking. In addition to source localization, two ocean sensing techniques are discussed in this dissertation. The feasibility of estimating ocean sound speed and temperature structure, using ship noise across a drifting volumetric array of hydrophones suspended beneath buoys, in a shallow water marine environment is investigated. Using the attenuation of acoustic energy along eigenray paths to invert for ocean properties such as temperature, salinity, and pH is also explored. In each of these cases, the theory is developed, tested using numerical simulations, and validated with data from acoustic field experiments.