Underwater Acoustic Propagation in the Philippine Sea

Underwater Acoustic Propagation in the Philippine Sea
Author: Andrew W. White
Publisher:
Total Pages: 181
Release: 2013
Genre: Hydrophone
ISBN:

In the spring of 2009, broadband transmissions from a ship-suspended source with a 284 Hz center frequency were received on a moored and navigated vertical array of hydrophones over a range of 107 km in the Philippine Sea. During a 60-hour period over 19 000 transmissions were carried out. The observed wavefront arrival structure reveals four distinct purely refracted acoustic paths: one with a single upper turning point near 80 m depth, two with a pair of upper turning points at a depth of roughly 300 m, and one with three upper turning points at 420 m. Individual path intensity, defined as the absolute square of the center frequency Fourier component for that arrival, was estimated over the 60-hour duration and used to compute scintillation index and log-intensity variance. Monte Carlo parabolic equation simulations using internal wave induced sound speed perturbations obeying the Garrett-Munk internal-wave energy spectrum were in agreement with measured data for the three deeper turning paths but differed by as much as a factor of four for the near surface-interacting path. Estimates of the power spectral density and temporal autocorrelation function of intensity were attempted, but were complicated by gaps in the measured time-series. Deep fades in intensity were observed in the near surface-interacting path. Hypothesized causes for the deep fades were examined through further acoustic propagation modeling and analysis of various available oceanographic measurements.

North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea
Author:
Publisher:
Total Pages: 12
Release: 2009
Genre:
ISBN:

The North Pacific Acoustic Laboratory (NPAL) program is intended to improve our understanding of (i) the basic physics of low-frequency, broadband propagation in deep water, including the effects of oceanographic variability on signal stability and coherence, (ii) the structure of the ambient noise field in deep water at low frequencies, and (iii) the extent to which acoustic methods, together with other measurements and coupled with ocean modeling, can yield estimates of the time-evolving ocean state useful for acoustic predictions. The goal is to determine the fundamental limits to signal processing in deep water imposed by ocean processes, enabling advanced signal processing techniques to capitalize on the three-dimensional character of the sound and noise fields.

Acoustic Seaglider: Planning for the Philippine Sea

Acoustic Seaglider: Planning for the Philippine Sea
Author:
Publisher:
Total Pages: 4
Release: 2008
Genre:
ISBN:

We want to integrate acoustics across naval and oceanographic applications. On one hand active and passive acoustics are used to detect submarines. On the other hand, acoustics are used to measure and better understand the ocean environment of the detection problem. Acoustics are essential to the underwater "infrastructure" tasks of navigation, communications, and time transfer. In all cases, the detailed understanding of acoustic propagation, ocean variability, temporal and spatial coherence ambient sound and the assimilation of data in models is essential for improved systems performance and the quantification of the associated uncertainty. Within the context of the Quantifying, Predicting, and Exploiting (QPE) Uncertainty DRI activity in the Philippine Sea, Seagliders can serve as a multipurpose platform for acoustics to support research in acoustic propagation, tomography, ambient sound, navigation, and communications. Assimilating data into models will improve oceanographic and acoustic predictions; this will test many elements of the integrated end-to-end data-modeling-prediction-detection system.

Underwater Acoustics

Underwater Acoustics
Author: Richard P. Hodges
Publisher: John Wiley & Sons
Total Pages: 386
Release: 2011-06-28
Genre: Science
ISBN: 1119957494

Offering complete and comprehensive coverage of modern sonar spectrum system analysis, Underwater Acoustics: Analysis, Design and Performance of Sonar provides a state-of-the-art introduction to the subject and has been carefully structured to offer a much-needed update to the classic text by Urick. Expanded to included computational approaches to the topic, this book treads the line between the highly theoretical and mathematical texts and the more populist, non-mathematical books that characterize the existing literature in the field. The author compares and contrasts different techniques for sonar design, analysis and performance prediction and includes key experimental and theoretical results, pointing the reader towards further detail with extensive references. Practitioners in the field of sonar design, analysis and performance prediction as well as graduate students and researchers will appreciate this new reference as an invaluable and timely contribution to the field. Chapters include the sonar equation, radiated, self and ambient noise, active sonar sources, transmission loss, reverberation, transducers, active target strength, statistical detection theory, false alarms, contacts and targets, variability and uncertainty, modelling detections and tactical decision aids, cumulative probability of detection, tracking target motion analysis and localization, and design and evaluation of sonars

Underwater Acoustic Modeling and Simulation

Underwater Acoustic Modeling and Simulation
Author: Paul C. Etter
Publisher: CRC Press
Total Pages: 639
Release: 2018-04-06
Genre: Technology & Engineering
ISBN: 1351679724

This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally

Underwater Acoustics and Ocean Dynamics

Underwater Acoustics and Ocean Dynamics
Author: Lisheng Zhou
Publisher: Springer
Total Pages: 126
Release: 2016-10-17
Genre: Science
ISBN: 9811024227

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.

Underwater Acoustic Modeling and Simulation, Fourth Edition

Underwater Acoustic Modeling and Simulation, Fourth Edition
Author: Paul C. Etter
Publisher: CRC Press
Total Pages: 557
Release: 2013-02-21
Genre: Technology & Engineering
ISBN: 1466564938

Underwater Acoustic Modeling and Simulation, Fourth Edition continues to provide the most authoritative overview of currently available propagation, noise, reverberation, and sonar-performance models. This fourth edition of a bestseller discusses the fundamental processes involved in simulating the performance of underwater acoustic systems and emphasizes the importance of applying the proper modeling resources to simulate the behavior of sound in virtual ocean environments. New to the Fourth Edition Extensive new material that addresses recent advances in inverse techniques and marine-mammal protection Problem sets in each chapter Updated and expanded inventories of available models Designed for readers with an understanding of underwater acoustics but who are unfamiliar with the various aspects of modeling, the book includes sufficient mathematical derivations to demonstrate model formulations and provides guidelines for selecting and using the models. Examples of each type of model illustrate model formulations, model assumptions, and algorithm efficiency. Simulation case studies are also included to demonstrate practical applications. Providing a thorough source of information on modeling resources, this book examines the translation of our physical understanding of sound in the sea into mathematical models that simulate acoustic propagation, noise, and reverberation in the ocean. The text shows how these models are used to predict and diagnose the performance of complex sonar systems operating in the undersea environment.

Underwater Acoustic Modelling and Simulation

Underwater Acoustic Modelling and Simulation
Author: P.C. Etter
Publisher: CRC Press
Total Pages: 447
Release: 2003-12-08
Genre: Technology & Engineering
ISBN: 1482295148

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 s

Underwater Acoustic Modelling and Simulation, Third Edition

Underwater Acoustic Modelling and Simulation, Third Edition
Author: P.C. Etter
Publisher: CRC Press
Total Pages: 447
Release: 2003-12-08
Genre: Technology & Engineering
ISBN: 0203417658

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.