Download or read book Environmentally Adaptive Sonar Technology EAST written by United States. Office of Naval Research and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "EAST (Environmentally Adaptive Sonar Technology) is an advanced sonar system concept being developed by Code 321, the Office of Naval Research (ONR), for the purpose of maximizing system performance in harsh environment, shallow water regions. The concepts discussed in this report focus on enhancing performance in shallow water but are intended to be applied to both active and passive systems regardless of water depth."--P. i.
Download or read book Environmentally Adaptive Sonar Technology EAST Project Report for Participation in the Littoral Warfare Advanced Development LWAD 99 3 Experiment written by Mitchell N. Shipley and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the Environmentally Adaptive Sonar Technology (EAST) project is to develop approaches to improve shallow water target detection for Navy active sonar systems. The current investigation involves using a time reversed acoustic pulse (TRAP) as a method of real time correction of propagation dispersion of the energy in an active sonar transmit waveform. The approach of the EAST project is predominantly experimentally based in the Naval Postgraduate Schools Advanced Acoustic Research Laboratory (AARL) shallow water tank facility. Computer modeling is also used to extend the experimental results to more realistic environments. The at sea experimental objectives of the EAST project in LWAD 99-3 were two fold: 1) Conduct a feasibility systems engineering test of a TRAP sonar syste% 2) At sea demonstration of about a 3dB improvement in SNR using a basic TRAP sonar approach over standard match filter active sonar signal processing for a single element sonar system.
Download or read book Environmentally Adaptive Sonar Technology EAST Project Report for Participation in the Littoral Warfare Advanced Development LWAD 99 3 Experiment written by Mitchell N. Shipley and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the Environmentally Adaptive Sonar Technology (EAST) project is to develop approaches to improve shallow water target detection for Navy active sonar systems. The current investigation involves using a time reversed acoustic pulse (TRAP) as a method of real time correction of propagation dispersion of the energy in an active sonar transmit waveform. The approach of the EAST project is predominantly experimentally based in the Naval Postgraduate Schools Advanced Acoustic Research Laboratory (AARL) shallow water tank facility. Computer modeling is also used to extend the experimental results to more realistic environments. The at sea experimental objectives of the EAST project in LWAD 99-3 were two fold: 1) Conduct a feasibility systems engineering test of a TRAP sonar syste% 2) At sea demonstration of about a 3dB improvement in SNR using a basic TRAP sonar approach over standard match filter active sonar signal processing for a single element sonar system.
Download or read book Environmentally Adaptive Sonar Techniques written by P.J. Eecen and published by . This book was released on 1999 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Incorporating Target Strength Into Environmentally adaptive Sonar Tracking written by Eric A. Rust and published by . This book was released on 2007 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmentally Adaptive and Through the Sensor Efforts at NRL written by and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Naval Research Laboratory's Marine Geosciences Division is conducting research in Through-The-Sensor and Environmentally Adaptive Sensor Techniques. NRL's AutoSurveyTM system is an environmentally adaptive technique developed to minimize survey time in an area while obtaining the desired seafloor coverage. The effective swath of a multibeam survey system depends on water depth, sound velocity conditions, seafloor properties, and sensor settings. AutoSurvey monitors these conditions and using intelligent navigation adjusts ship track accordingly to achieve a desired swath overlap. The real-time system processes the edge of good swath data at the end of each survey line and lays down the next survey line on the fly based on actual coverage. As a result excessive overlap in deep areas and data gaps in shoal areas are avoided. AutoSurvey timesavings are slope dependent. Results from actual surveys have demonstrated timesavings of 10% with as little as loot slope, and up to 60% for rugged terrain. AutoSurvey has been transitioned to the Naval Oceanographic Office (NAVOCEANO) for use on their T-AGS vessels. Additionally NRL has worked with ARL/UT in the development of a real- time situational awareness tool for the SQQ-32 mine hunting sonar. In this environmentally adaptive technique, real-time reverberation statistics from the SQQ-32 end target signal computations involving the sound speed profile are used to compute sonar detection performance. The Sonar Performance Monitoring System displays detection performance as a function of bearing and range in four colors, good to poor, responsive to changing environmental conditions and the sonar configuration. Through-The-Sensor (TTS) concepts use fleet assets to collect tactical environmental data that can be used to refresh the environmental picture. NRL's Acoustic Seafloor Classification System (ASCS) uses inversion and signal processing techniques to determine acoustic impedance and seafloor properties.
Download or read book Environmentally Adaptive Noise Estimation for Active Sonar written by Robert Bareš and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise is frequently encountered when processing data from the natural environment, and is of particular concern for remote-sensing applications where the accuracy of data gathered is limited by the noise present. Rather than merely accepting that sonar noise results in unavoidable error in active sonar systems, this research explores various methodologies to reduce the detrimental effect of noise. Our approach is to analyse the statistics of sonar noise in trial data, collected by a long-range active sonar system in a shallow water environment, and apply this knowledge to target detection. Our detectors are evaluated against imulated targets in simulated noise, simulated targets embedded in noise-only trial data, and trial data containing real targets. First, we demonstrate that the Weibull and K-distributions offer good models of sonar noise in a cluttered environment, and that the K-distribution achieves the greatest accuracy in the tail of the distribution. We demonstrate the limitations of the Kolmogorov-Smirnov goodness-of-fit test in the context of detection by thresholding, and investigate the upper-tail Anderson-Darling test for goodness-of-fit analysis. The upper-tail Anderson-Darling test is shown to be more suitable in the context of detection by thresholding, as it is sensitive to the far-right tail of the distribution, which is of particular interest for detection at low false alarm rates. We have also produced tables of critical values for K-distributed data evaluated by the upper-tail Anderson-Darling test. Having established suitable models for sonar noise, we develop a number of detection statistics. These are based on the box-car detector, and the generalized likelihood ratio test with a Rician target model. Our performance analysis shows that both types of detector benefit from the use of the noise model provided by the K-distribution. We also demonstrate that for weak signals, our GLRT detectors are able to achieve greater probability of detection than the box-car detectors. The GLRT detectors are also easily extended to use more than one sample in a single test, an approach that we show to increase probability of detection when processing simulated targets. A fundamental difficulty in estimating model parameters is the small sample size. Many of the pings in our trial data overlap, covering the same region of the sea. It is therefore possible to make use of samples from multiple pings of a region, increasing the sample size. For static targets, the GLRT detector is easily extended to multi-ping processing, but this is not as easy for moving targets. We derive a new method of combining noise estimates over multiple pings. This calculation can be applied to either static or moving targets, and is also shown to be useful for generating clutter maps. We then perform a brief performance analysis on trial data containing real targets, where we show that in order to perform well, the GLRT detector requires a more accurate model of the target than the Rician distribution is able to provide. Despite this, we show that both GLRT and box-car detectors, when using the K-distribution as a noise model, can achieve a small improvement in the probability of detection by combining estimates of the noise parameters over multiple pings.
Download or read book Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance written by Nicholas G. Pace and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: The limiting influence of the environment on sonar has long been recognised as a major challenge to science and technology. As the area of interest shifts towards the lit toral, environmental influences become dominant both in time and space. The manyfold challenges encompass prediction, measurement, assessment and adaptive responses to maximize the effectiveness of systems. Although MCM and ASW activities are dom inated in different ways and scales by the environment, both warfare areas have had to consider the significantly changing requirements posed by operations in the littoraL The fundamental scientific issues involved in developing models relating acoustics to the environment are matched in difficulty by the need for data for their validation and eventual practical use for prediction. In many instances the need is for on-line adaptation of systems to changing circumstances whilst other needs are for the Ionger term planning activities. This book and the attached full-color CD are the proceedings of a conference organ ised by the SACLANT Undersea Research Centre, held at Villa Marigola, Lerici, Italy, on 16-20 September 2002. The fundamental problems associated with environmental 1 variability and sonar were explored at a previous SACLANTCEN conference in 1990. These problems have not gone away but, on the one hand are exaggerated by the move to the littoral and on the other hand, are open to treatrnent in new ways that advances in technology and computer power allow.
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 Underwater Acoustic Modeling and Simulation written by Paul C. Etter and published by CRC Press. This book was released on 2017-12-19 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Anti submarine Warfare written by Sangram Singh Byce and published by . This book was released on 2006 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Model based Algorithm for Environmentally Adaptive Bathymetry and Sound Velocity Profile Estimation written by David Bruce Cousins and published by . This book was released on 2005 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NRL Review written by and published by . This book was released on 2001 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Sonar Signal Processing Method and System written by and published by . This book was released on 2003 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method and system for processing received sonar signals. The method and system generate bearing data signals based on the received sonar signal. The method and system continuously determine the signal strength of the received sonar signal and also continuously determine the total noise from the received sonar signal in the ocean environment in which the target is located. The method and system provide a sensor gain in response to the determined total noise and the signal strength, and adaptively calculate filter coefficients from the sensor gain and the determined total noise. The method and system also filter the generated bearing data signals using a filter having the calculated filter coefficients.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thinking in Systems written by Donella Meadows and published by Chelsea Green Publishing. This book was released on 2008-12-03 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The classic book on systems thinking—with more than half a million copies sold worldwide! "This is a fabulous book... This book opened my mind and reshaped the way I think about investing."—Forbes "Thinking in Systems is required reading for anyone hoping to run a successful company, community, or country. Learning how to think in systems is now part of change-agent literacy. And this is the best book of its kind."—Hunter Lovins In the years following her role as the lead author of the international bestseller, Limits to Growth—the first book to show the consequences of unchecked growth on a finite planet—Donella Meadows remained a pioneer of environmental and social analysis until her untimely death in 2001. Thinking in Systems is a concise and crucial book offering insight for problem solving on scales ranging from the personal to the global. Edited by the Sustainability Institute’s Diana Wright, this essential primer brings systems thinking out of the realm of computers and equations and into the tangible world, showing readers how to develop the systems-thinking skills that thought leaders across the globe consider critical for 21st-century life. Some of the biggest problems facing the world—war, hunger, poverty, and environmental degradation—are essentially system failures. They cannot be solved by fixing one piece in isolation from the others, because even seemingly minor details have enormous power to undermine the best efforts of too-narrow thinking. While readers will learn the conceptual tools and methods of systems thinking, the heart of the book is grander than methodology. Donella Meadows was known as much for nurturing positive outcomes as she was for delving into the science behind global dilemmas. She reminds readers to pay attention to what is important, not just what is quantifiable, to stay humble, and to stay a learner. In a world growing ever more complicated, crowded, and interdependent, Thinking in Systems helps readers avoid confusion and helplessness, the first step toward finding proactive and effective solutions.
Download or read book Commerce Business Daily written by and published by . This book was released on 1998-07 with total page 1182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
