Acoustic Invisibility for Elliptic Objects by
The book investigates acoustic cloaking for elliptical targets, starting from the development of a systematic approach to deal with such non-axisymmetrical shapes by adopting transformation acoustics in elliptic coordinates, and concluding with numerical and experimental validation of a microstructured cloak in the underwater environment. The book thus comprises all the steps from theory to practice that led to the first experimental validation of acoustic invisibility for non-cylindrical objects, whose results are presented in the last chapter. Indeed, despite Transformation Theory is now an established tool to design material distributions capable to unlock the design of invisibility devices, it is not trivial to apply it for shapes different than the sphere and the cylinder, which are thus the ones mainly addressed in the literature. This book paves the way for exploration of other shapes, demonstrating the effectiveness of a pentamode cloak in reducing the acoustic visibility of an elliptical target, and discussing design choices that can make the implementation of the required microstructure less cumbersome despite the lack of axial symmetry of the problem, from both the numerical and manufacturing point of views
An Adaptive Approach for Precise Underwater Vehicle Control in Combined Robot-Diver Operations by
Joint robot-human operations potentially increase the efficiency, effectiveness and safety of the tasks they perform. The utilization of an autonomous underwater vehicle (AUV) as a robotic diver’s assistant demands joint, dynamic operations involving precise physical interactions between an AUV, human divers, and the environment, which, in turn, requires a robust, accurate control system. A robot acting as a dive assistant would perform tasks such as tool carrying, worksite illumination, or other general assistance jobs that a dive buddy might perform. Such precise control of the AUV normally requires accurate knowledge of the vehicle’s dynamics; however, this high level of accuracy is difficult to obtain without the employment of extensive system identification efforts. Additionally, the utility of the resulting model is greatly diminished if environmental conditions or vehicle configuration change frequently or unexpectedly. An ideal control system allows the AUV to switch between operational modes and objectives while accounting for uncertain environmental conditions, payload configurations, and possible failures of onboard actuators. Adaptive control has many applications in the underwater domain and can give a robotic diver’s assistant the flexibility required to enable joint robot-diver operations. Therefore, two adaptive control system approaches, Model Reference Adaptive Control and L1 Adaptive Control, are investigated here for heave control of the Tethered, Hovering Autonomous Underwater System
Adaptive Methods in Underwater Acoustics by
The NATO Advanced Study Institute on Adaptive Methods in Underwater Acoustics was held on 30 July - 10 August 1984 in LLineburg, Germany. The Institute was primarily concerned with signal processing for underwater appl ica tions. The majority of the presentations, when taken together, yield a definite picture of the present status of understanding of adaptive and high resolution processing, setting out the progress achieved over the past four years together with the major problem areas remaining. Major effort was made to obtain a commensurate contribution of tutorial and advanced research papers. It is my hope that the material in this volume may be equally well suited for students getting an introduction to some of the basic problems in underwater signal processing and for the professionals who may obtain an up-to-date overview of the present state of the art. This might be especially useful in view of the controversy and lack of adequate interrelationships which have marked this rapidly expanding field in the past. Practical reinforcement of this picture is provided by the material concerning digital and optical processing technology, giving some guidance to achievable adaptive and high resolution techniques with current processing devices. The formal programme was extended and detailed by a series of six evening work shops on specific topics, during which informal discussions took place among the participants. Summaries of these workshops are also included in these Proceedings.
Advanced Signal Processing Handbook by
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.
Development and Testing of Navigation Algorithms for Autonomous Underwater Vehicles by
In addition to proposing novel algorithms for estimating the attitudes and positions of AUVs using low-cost sensors and taking into account magnetic disturbances and ocean currents, the book provides readers with extensive information and a source of inspiration for the further development and testing of navigation algorithms for AUVs.
Distributed Remote Sensing for Naval Undersea Warfare by
Provides a path by which useful DRS systems can be applied to naval USW problems, and by which ongoing science and technology efforts can be directed toward useful options. This report contains information as described in 5 USC 552(b).
Fundamentals of Acoustic Field Theory and Space-Time Signal Processing by
Providing a wealth of information on fundamental topics in the areas of linear air and underwater acoustics, as well as space-time signal processing, this book provides real-world design and analysis equations. As a consequence of the interdisciplinary nature of air and underwater acoustics, the book is divided into two parts: Acoustic Field Theory and Space-Time Signal Processing. It covers the fundamentals of acoustic wave propagation as well as the fundamentals of aperture theory, array theory, and signal processing. Starting with principles and using a consistent, mainly standard notation, this book develops, in detail, basic results that are useful in a variety of air and underwater acoustic applications. Numerous figures, examples, and problems are included
Fundamentals of Inertial Navigation, Satellite-Based Positioning and Their Integration by
Equally useful to those new to the field as well as experienced engineers, this comprehensive reference includes step-by-step details of derivations and implementation, providing an up-to-date guide to the core elements of INS and GPS.
Fundamentals of underwater acoustics by
This textbook on Underwater Acoustics has a structure that is more organic than logical. It thereby unifies diverse areas of research, including topics of signal processing, the sonar equation, sources and receivers, scattering and reverberation, wave propagation, propagation models, and inverse problems. It also provides code fragments written in Python which complement the discussion. This is a book written for both beginners and specialists, as well as for biologists, oceanographers, computer engineers, physicists, and mathematicians, and for civilian and naval personnel who are looking for a introductory overview of the topic
GNSS Environmental Sensing by
This book is the second edition of Environmental Monitoring using GNSS and highlights the latest developments in global navigation satellite systems (GNSS). It features a completely new title and additional chapters that present emerging challenges to environmental monitoring―“climate variability/change and food insecurity.”
Since the publication of the first edition, much has changed in both the development and applications of GNSS, a satellite microwave remote sensing technique. It is the first tool to span all four dimensions of relevance to humans (position, navigation, timing and the environment), and it has widely been used for positioning (both by military and civilians), navigation and timing. Its increasing use is leading to a new era of remote sensing that is now revolutionizing the art of monitoring our environment in ways never imagined before.
Microelectronics and Signal Processing by
This book is about general and specific areas involved in electrical and electronics engineering which comprises broad subjects such as MEMS and Microfluidics, VLSI, Communication and Signal Processing. This book discusses the recent trends in various aspects of research areas for diverse applications like biomedical, biochemical, and power source systems. It also discusses modelling, simulating, and prototyping of the different electronic-based systems for carrying out varied applications. With this book, the readers will understand the multiplatform fundamentals guiding electrical and biomedical devices that form the current features such as automation, integration, and miniaturization of a particular device.
Position, Navigation, and Timing Technologies in the 21st Century, Volumes 1 And 2 by
Knowledge of your current location is now taken for granted by people worldwide. This state of affairs is largely due to the advent of satellite-based navigation systems, particularly the Global Positioning System (GPS). These Global Navigation Satellite Systems (GNSS) are still rapidly evolving with more capability and even greater robustness. The fundamental purpose of all of them is determining location in four dimensions--3 of geographical positions plus time. A user is indifferent to the source of location knowledge--any technique will do if it is reliable. While much of this book is devoted to satellite-based navigation systems, or SatNavs, we intend to give full explanations of virtually all modern sources of position, navigation, and time (PNT)"-- Provided by publisher
Recent Advances in Underwater Signal Processing by
Seventy-one percent of the Earth is covered by oceans, which plays an important role in human life (ecological regulation, living resources, mineral resources, etc.). Underwater equipment including sonar and radar can help us to better understand the ocean. Using these technologies, topography, underwater communication, target detection, localization, imaging, and ocean monitoring can be easily carried out. Signal processing and electronics techniques have achieved great progress in recent years. Thanks to these developments, the novel theories, mechanisms, and processing techniques of underwater equipment have also been pushed into a new era.
This Special Issue aims to highlight recent advancements, developments, and applications in underwater signal processing methodologies including characterization, simulation, real data processing, as well as applications to underwater engineering. In general, any contributions related to underwater signal processing or ocean signal processing will be considered.
Sensor and Data Fusion Concepts and Applications by 
Sparse Arrays for Radar, Sonar, and Communications by
Sparse Arrays for Radar, Sonar, and Communications discusses various design approaches of sparse arrays, including those seeking to increase the corresponding one-dimensional and two-dimensional virtual array apertures, as well as others that configure the arrays based on solutions of constrained minimization problems.
Tracking and Data Fusion: A Handbook of Algorithms by Undersea Communications Between Submarines and Unmanned Undersea Vehicles in a Command and Control Denied Environment by
Nuclear powered submarines are most vulnerable to detection and attack while at periscope depth. Submarines also have specific communication and time requirements they have to meet and the primary method of transmitting and receiving data is via satellite, which requires the submarine to be at periscope depth. This means that in a command and control denied environment (C2DE), a submarine may be incapable of receiving orders or transmitting required reports. In order to meet its communications requirements, the submarine has to navigate outside of the denied environment, conduct all necessary satellite communications, and proceed back to the C2DE zone. Through great improvements in unmanned underwater vehicle (UUV) technology and the development of new line-of-sight rapid data transmission methods, submarines may be able to operate in C2DEs and conduct all necessary communications without ever going to periscope depth. This study analyzes different configurations for UUV and submarine interaction in a C2DE area using a series of models in the Map Aware Non- Uniform Automata (MANA) modeling environment. This analysis explores the value of several different UUV characteristics as well as undersea garage configurations in minimizing the time it takes for a submarine to conduct its communications, the latency of the data received, and the cost of construction for the system. The system as modeled shows that the combination of the UUV and blue-green laser can provide the submarine with service times comparable to the time it takes for a submarine to reach periscope depth and expected data latency of less than an hour.
Underwater acoustic channel by
This book introduces sonar system and acoustic channel model, average energy channel, coherent multipath channel, the theoretical basis for the stochastic time-varying space-variant channel, slowly time-varying coherent multipath channel, and reverberation channel. Based on the basic theory of underwater acoustic channels and the various characteristics of the marine acoustic environment factor, this textbook aims to help students understand the impact of the marine acoustic channel on the sonar system. It helps students to grasp underwater acoustic signal processing principles and obtain the ability to solve practical problems in underwater acoustic channel engineering. Finally, it aims at laying a foundation for the further sonar system design. This textbook is recommended for graduate or undergraduate students in the field of sonar signal processing, underwater acoustic engineering, as well as some related subjects of marine technology
Underwater Acoustic Digital Signal Processing and Communication Systems by
Underwater acoustic digital signal processing and communications is an area of applied research that has witnessed major advances over the past decade. Rapid developments in this area were made possible by the use of powerful digital signal processors (DSPs) whose speed, computational power and portability allowed efficient implementation of complex signal processing algorithms and experimental demonstration of their performance in a variety of underwater environments. The early results served as a motivation for the development of new and improved signal processing methods for underwater applications, which today range from classical of autonomous underwater vehicles and sonar signal processing, to remote control underwater wireless communications. This book presents the diverse areas of underwater acoustic signal processing and communication systems through a collection of contributions from prominent researchers in these areas. Their results, both new and those published over the past few years, have been assembled to provide what we hope is a comprehensive overview of the recent developments in the field. The book is intended for a general audience of researchers, engineers and students working in the areas of underwater acoustic signal processing. It requires the reader to have a basic understanding of the digital signal processing concepts. Each topic is treated from a theoretical perspective, followed by practical implementation details. We hope that the book can serve both as a study text and an academic reference.