Tutorials
We are offering a range of high quality tutorials from subject matter experts. Please take advantage of this opportunity to register for and attend tutorials of most benefit to you. These tutorials will take place on Monday 24 May.
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Time |
Bayside 101 |
Bayside 102 |
Bayside 103 |
Bayside 104 |
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0830-1200 |
William Carey |
Philippe |
Marc Pinto |
Milica Stojanovic |
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Shallow water acoustics |
T03 Stochastic matched filters for sonar signals |
T05 Overview of high resolution sonar |
T07 Underwater Communications |
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1300-1630 |
Stuart Anderson |
Stefan Williams |
Roy E Hansen |
William Kirkwood |
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T02 High Frequency Surface Wave Radar |
T04 Localisation and Mapping |
T06 Synthetic aperture sonar |
T08 AUV technology |
Abstracts and Biographies
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T01
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Shallow water acoustics
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Presenter
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Prof. William Carey
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Time
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0830 – 1200
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Room
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Bayside 101
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Abstract
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FUNDAMENTAL UNDERWATER ACOUSTICS AND BOTTOM-
INTERACTING SHALLOW WATER ACOUSTICS
This tutorial intended for engineers and scientists concerned with the assessment of long range acoustic communication and sound transmission in deep and shallow water. The bottom is typically a sandy-sediment and has the dominant influence on the attenuation. The present tutorial surveys the basic science and experimental results that will enable one to make realistic interpretations and predictions. The session plan consists of a primer on the fundamentals of underwater acoustics, beginning with the wave equation, deep-water propagation, shallow water propagation, and the question of standards and a brief overview of ambient noise. The shallow water model of the Pekeris is discussed, progressing to a discussion of the modal solutions for realistic downward refracting sound velocity profiles, with a detailed examination of sample calculations for propagation in range-independent oceans. An assessment and review of representative effects of attenuation and a discussion of the importance of attenuation is presented. Current physical models of ocean sediments are reviewed, beginning with the original phenomenological model introduced by Biot in 1956. Later evidence justifying and extending this model, especially the rigorous theory of Burridge and Keller in 1981, is reviewed, and the applicable predictions of the theory, such as that the attenuation in the sediment varies as the square of the frequency at low frequencies. The fourth hour is concerned with the field measurements of sediment properties and of how these can be incorporated into propagation predictions.
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Biography
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William M. Carey is a Professor of Aerospace and Mechanical Engineering at Boston University, an Adjunct Professor of Applied Mathematics at the Rensselaer Polytechnic Institute and an Adjunct Scientist at the Woods Hole Oceanographic Institution. He was the Editor of the Journal of Oceanic Engineering is currently an Associate Editor for Underwater Acoustics, the Journal of the Acoustical Society o America. He has been a Physicist at several the Naval Laboratories and the ASW Program Manager at the Defense Advanced Project Agency. At the University of Chicago’s Argonne National Laboratory, he was an Associate Scientist and Section Manager of acoustic surveillance. He has been a consultant to both industry and government in the areas of non-destructive testing, nuclear science/ environmental measurements, and applied ocean acoustics.
Dr. Carey is a Fellow of the Acoustical Society of America, a Fellow of the IEEE Oceanic Engineering Society, a full member of Sigma Xi, a member of the Connecticut Academy of Science and Engineering, and also a member of the Cosmos Club. He is the recipient of the IEEE-OES Distinguished Technical Achievement Award, the IEEE-OES Distinguished Service Award and an IEEE Millennium Medal. He recently received Pioneer of Underwater Acoustics Silver Medal. He received the B.S. degree in Mechanical Engineering, the M.S. degree in Physics, and the Ph.D. degree in Nuclear Science from the Catholic University of America.
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| T02 | High Frequency Surface Wave Radar |
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Presenter
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Dr Stuart Anderson
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Time
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1300 - 1630 |
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Room
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Bayside 101 |
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Abstract
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HF SURFACE WAVE RADAR HF surface wave radars exploit the electromagnetic ground wave mode of propagation to illuminate the ocean surface at ‘over-the-horizon’ ranges, up to several hundred kilometers. In most cases they are deployed at coastal sites within ~ 100 metres of the shoreline. Echoes provide information on waves and currents, as well as the presence of ships and other discrete features. Existing HFSWR systems are clustered into two main categories : (i) low power, reasonably compact remote sensing systems designed to monitor ocean currents and measure wave spectra, and (ii) high power military systems with greater sensitivity and extended range coverage, employed for detection and tracking of ships, smaller ocean-going vessels and low-flying aircraft which fall below the horizon of microwave ‘line-of-sight’ radar systems. In addition, mention should be made of ship-borne HFSWR systems, though these remain the subject of research and development rather than being fitted to operational platforms. This tutorial sets out to describe the principle characteristics of HFSWR systems, both the low power remote sensing systems and the military surveillance radars. The main subsystems of such radars are described, emphasising the factors which impact on HFSWR design. The electromagnetics of ground wave propagation and scattering is treated in some depth. A fairly detailed account of the geometry and dynamics of the ocean surface is provided, since it is effectively this surface that constitutes the ‘channel’ connecting radar to target, as well as serving as the target of interest in the case of remote sensing. The issue of radar siting is treated in detail, as in practice this often entails important compromises in radar design and capability. Advanced signal processing techniques are discussed and their efficacy demonstrated. These precepts are then brought together to show how HFSWR can address a wide range of oceanographic remote sensing missions. A comprehensive overview of the oceanographic remote sensing capabilities of HFSWR is presented, balanced by a frank account of some of the limitations which have been encountered in real-world experience. Remote sensing products from a number of HFSWR systems around the world are used to illustrate the contributions that HFSWR can make to diverse fields of oceanography, from hydrodynamics to the signatures of climate change. |
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Biography
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Stuart Anderson holds BSc (Hons) and PhD degrees from the University of Western Australia. Since 1972 Dr Anderson has worked in the Australian Defence Science and Technology Organisation, where he was responsible for developing the ocean surveillance and remote sensing capabilities of the Jindalee over-the-horizon skywave radar system and the Iluka HF surface wave radar system. He has worked as a visiting scientist in several countries, contributing to various national and international HF radar programs, as well as holding adjunct appointments at Curtin University of Technology (Professor of Applied Physics), the University of New South Wales (Professor of Mathematics), and the University of Rennes I, France, (Professor and Docteur honoris causa). He was the recipient of the 1992 Minister of Defence Award for Research Achievement, and is an elected Fellow of the Electromagnetics Academy. His active research interests include electromagnetic scattering, ionospheric physics, radio oceanography, physics-based signal processing, microwave radar polarimetry, passive coherent location, and the exploitation of HF radar systems for a wide variety of missions. |
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T03
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Stochastic matched filters for sonar signals
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Presenter
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Prof. Philippe Courmontagne
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Time
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0830 - 1200
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Room
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Bayside 102
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Abstract
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STOCHASTIC MATCHED FILTERS FOR DETECTION AND DENOISING
OF SONAR SIGNALS
In several domains of signal processing, such as detection or de-noising, it may be interesting to provide a second-moment characterization of a noise-corrupted signal in terms of uncorrelated random variables. Doing so, the noisy data could be described by its expansion into a weighted sum of known vectors by uncorrelated random variables. Depending on the choice of the basis vectors, some random variables are carrying more signal of interest information than noise ones. This is the case, for example, when a signal disturbed by a white noise is expanded using the Karhunen-Loève expansion. In these conditions, it is possible either to approximate the signal of interest by keeping only its associated random variables, or to detect a signal in a noisy environment with an analysis of the random variable power. The purpose of this tutorial is to present such an expansion, available for both the additive and multiplicative noise cases, and its application to detection and de-noising. This noisy random signal expansion is known as the stochastic matched filter, where the basis vectors are chosen so as to maximize the signal to noise ratio after processing.
This tutorial is divided into three parts: - The first part concerns the theory itself: the stochastic matched filter theory will be described for 1-D discrete-time signals and its extension to 2-D discrete-space signals. Furthermore, a study will be realized on two different noise cases: the white noise case and the speckle noise case. - In the second part, the stochastic matched filter will be described in a detection context and this method will be confronted with signals resulting from underwater acoustics. The results obtained are then compared with those resulting from the classical matched filter theory. - In the last part, the stochastic matched filter will be presented in a de-noising context. The de-noising being performed by a limitation to order Q of the noisy data expansion, two criteria to determine Q will be introduced. Experimental results on real SAS data are given to evaluate the performances of such an approach. This tutorial is intended for people or scientists connected with 1-D/2-D signal or array processing, and interested to have a fly-over about these effective methods. |
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Biography
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Philippe Courmontagne was born in 1970. He received the Ph. D. degree in Physics at the University of Toulon (France) in 1997. In 1999, he became Professor in a French electronic engineering school: the Institut Supérieur de l’Électronique et du Numérique (ISEN Toulon, France), in the field of signal processing and image processing. He joined in 2001 the Provence Materials and Microelectronics Laboratory (L2MP UMR CNRS 6137), which is a unit of the French national research center (CNRS). In 2005, he obtained his Habilitation (HDR - Habilitation to Supervise Research) for his works in the field of noisy signal expansion. In 2007, he has been elected to the degree of IEEE Senior Member in recognition of professional standing for his works in the field of signal de-noising (SAR, SAS images), signal detection in noisy environment and signal transmission.
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T04
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Localisation and Mapping
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Presenter
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Dr Stefan Williams
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Time
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1300 - 1630
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Room
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Bayside 102
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Abstract
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LOCALISATION AND MAPPING
This tutorial will examine current developments in the area of localisation and mapping for underwater systems. In particular, we will review methods for Simultaneous Localisation and Mapping (SLAM) using both high resolution optical and acoustic data collected by underwater vehicles. We will demonstrate how observations of the terrain from the vehicle's mapping sensors can be used as part of the navigation solution to correct for drift in the vehicle's position estimate. Techniques for three dimensional scene reconstruction, visualisation, novelty detection and classification will also be described. Results from recent AUV deployments will be used to be illustrate the process. |
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Biography
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Dr. Stefan B. Williams is a Senior Lecturer in the University of Sydney's School of Aerospace, Mechanical and Mechatronic Engineering. He is a member of the Australian Centre for Field Robotics where he leads the Marine Robotics group. He is also the head of Australia's Integrated Marine Observing System AUV Facility. His research interests include Simultaneous Localisation and Mapping in unstructured underwater environments as well as algorithms for autonomous navigation and control. He received his PhD from the University of Sydney in 2002 and completed a Bachelor of Applied Science with first class honours in 1997 at the University of Waterloo, Canada.
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T05
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Overview of high resolution sonar
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Presenter
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Dr Marc Pinto
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Time
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0830 – 1200
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Room
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Bayside 103
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Abstract
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HIGH RESOLUTION SONAR SYSTEMS
The basic principles of aperture will be reviewed including near field operation and related concepts such as Fresnel distance, focusing and depth of field. Next, principles of aperture sampling, i.e. array design, will be presented including undersampled arrays exhibiting grating lobes and their minimization with the two-way beampattern of the transmitter and receive element. Frequency dependence and wideband operation will be discussed as well as the impact of calibration errors and uncertainties in the sound velocity profile on sonar resolution. This will be illustrated by different high resolution sonar designs for seafloor imaging such as dynamic focusing, dynamic aperture and synthetic aperture sonar. The basic sonar equation will be used to illustrate some of the factors limiting the range of high resolution sonar systems. It is shown how the signal to noise ratio can be enhanced by the frequency modulation and state of the art front end electronics. More fundamental factors such as cross-range resolution and multipath propagation are discussed as well as improved sonar designs which attempt to push back these limits. Finally the design of bathymetric imaging systems will be discussed. The two competing designs, which are multi-beam echo-sounders and interferometric systems, will be presented and their respective merits and drawbacks will be discussed using criteria such as area coverage, bathymetric accuracy and spatial resolution as well as robustness. The principles of angle of arrival estimation for random seafloor echoes (rather than echoes of deterministic targets) will be discussed in detail including fundamental factors limiting the accuracy such as baseline decorrelation. |
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Biography
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Marc Pinto was born in Wellington, India in 1960. He graduated from the Ecole Nationale des Ponts et Chaussees, Paris (France) in 1983. From 1985 to 1989 and 1989 to 1993 he worked as a research engineer for Thomson-CSF, specializing in the development of finite element techniques for solving non-linear magnetostatics to support the modeling of the magnetic recording process. In 1991, he received the Ph. D. degree in Solid State Physics from the University of Paris, Orsay. In 1993 he joined Thomson-Sintra ASM (now Thales Underwater Systems) as Head of the Signal Processing Group, specializing in research into advanced MDM and airborne ASW sonar. In 1997 he joined the NATO Saclant Undersea Research Center, La Spezia, Italy as principal scientist. He was appointed Head of the Mine Countermeasures Group, in the Signal and Systems Division in 1998 and held this position until the Group was dissolved in 2000. From 2000 to 2004 he conducted, as project leader, research into synthetic aperture sonar systems for hunting proud and buried mines. In 2004 he was appointed Head of the Expeditionary MCM and Port Protection Department where he presently oversees the research into AUV-based mine-hunting, electronic mine countermeasures and harbour defence.
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T06
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Synthetic aperture sonar
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Presenter
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Dr Roy E Hansen
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Time
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1300 - 1630
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Room
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Bayside 103
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Abstract
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SYNTHETIC APERTURE SONAR
This tutorial will describe the principles, benefits and challenges of synthetic aperture sonar (SAS) imaging of the seafloor. The tutorial starts with the basic principles of SAS including derivation of resolution and area coverage. The similarities and differences between SAS, synthetic radar aperture radar (SAR) and seismic exploration will be shown. Next, the frequency dependence in SAS will be discussed. The tutorial continues to describe the challenges in SAS. These are: How to navigate with sufficient accuracy to obtain well focussed images in SAS; The effect of varying ocean environment on SAS; The effect of platform behaviour on SAS. SAS in rough terrain or SAS on non-straight paths; SAS in shallow waters or in areas of multipath; The tutorial will describe critical design for robust SAS, and how to do robust SAS processing. Finally, the tutorial will describe the properties of SAS images, and shows techniques to enhance or suppress specific properties. This includes shadow enhancement, echo enhancement and multi-aspect imagery.
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Biography
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Roy Edgar Hansen received the (M.Sc.) degree in physics in 1992, and the Ph.D. in physics in 1999, both from the University of Tromso, Norway. The Ph.D. thesis title is Measurements in the Mixed Layer by a Bistatic multi-CW Doppler Sonar. From 1992 to 2000 he was with the Norwegian research company TRIAD, working on multistatic sonar, multistatic radar, SAR and underwater communications. Since 2000, he has been working at the Norwegian Defence Research Establishment (FFI), Kjeller, Norway. He is currently principal scientist and project manager for the HUGIN autonomous underwater vehicle development and the synthetic aperture sonar development at FFI. He is also adjunct associated professor at Centre for Imaging at University in Oslo, Norway.
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T07
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Underwater Communications
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Presenter
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Dr Milica Stojanovic & Lee Freitag
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Time
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0830 - 1200
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Room
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Bayside 104
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Abstract
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UNDERWATER ACOUSTIC COMMUNICATIONS
Wireless information transmission is an enabling technology for the development of future ocean-observation systems, whose applications range from marine biology to oil industry, and involve the emerging concepts of cooperating autonomous vehicles and ad-hoc deployable sensor networks. Communication between such devices often relies on transmission of acoustic waves, since electro-magnetic waves propagate only over very short distances underwater. However, acoustic signals are confined to low frequencies (usually no more than several tens of kHz) making the available bandwidth extremely limited.
Within a constrained bandwidth, acoustic communications are governed by propagation that occurs over multiple paths and at low speed (nominally 1500 m/s). Delay spreading over tens or even hundreds of milliseconds results in a frequency-selective signal distortion, while motion creates an extreme Doppler effect. The worst properties of radio channels—poor link quality of a mobile terrestrial channel, and long delay of a satellite channel—thus appear combined in an underwater acoustic channel, which is generally recognized as one of the most difficult communication media in use today.
The quest for high rate communications over these channels is tightly coupled with the use of bandwidth-efficient modulation methods and signal processing solutions that can counteract the channel distortions. Since the early 90’s, when adaptive equalization was employed to demonstrate the feasibility of phase-coherent detection underwater, research has yielded innovative signal processing solutions, as well as the first networking concepts for underwater acoustic systems.
This lecture offers a top-level overview of the basic concepts of acoustic communications:
• Channel characteristics: attenuation, noise, multipath and Doppler spreading
• Modulation/detection: single-carrier and multi-carrier (OFDM) broadband methods; equalization, synchronizations, diversity combining; multi-input multi-output (MIMO) communication • Networking: topology/architecture selection, resource allocation • Multiple access and channel sharing: deterministic (e.g., TDMA/CDMA) and random (MAC, routing).
Acoustic modem implementation will also be discussed, as it pertains to the Woods Hole Oceanographic Institution’s “micro-modem.”
Throughout the lecture, the emphasis will be on the fundamental differences between the acoustic and radio systems, and various signal processing concepts will be discussed through a series of experimental data examples, which illustrate transmission over shallow and deep water acoustic channels at highest bit-rates demonstrated to date.
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Biographies
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Dr Milica Stojanovic
Milica Stojanovic graduated from the University of Belgrade, Serbia, in 1988, and received the M.S. and Ph.D. degrees in electrical engineering from Northeastern University, Boston, MA, in 1991 and 1993. After a number of years with the Massachusetts Institute of Technology, where she was a Principal Scientist, she joined the faculty of Electrical and Computer Engineering Department at Northeastern University in 2008. She is also a Guest Investigator at the Woods Hole Oceanographic Institution, and a Visiting Scientist at MIT. Her research interests include digital communications theory, statistical signal processing and wireless networks, and their applications to mobile radio and underwater acoustic communication systems. Milica is an Associate Editor for the IEEE Journal of Oceanic Engineering and the IEEE Transactions on Signal processing.
Lee Freitag
Lee Freitag holds BS and MS degrees in Electrical Engineering from the University of Alaska, Fairbanks which he received in 1986 and 1987 respectively. He is currently a Senior Engineer at the Woods Hole Oceanographic Institution where he has worked on projects related to underwater acoustics for twenty years. His research programs focus on underwater acoustic communication and navigation with a strong focus on unmanned underwater vehicles, sensors and submarine systems.
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T08
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AUV technology
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Presenter
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William Kirkwood
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Time
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1300 - 1630
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Room
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Bayside 104
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Abstract
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AUV TECHNOLOGY AND APPLICATION BASICS
AUV Application Basics is a short course that provides an overview of current AUV technologies and operations. The objective is to establish a basic understanding of what currently available AUVs for oceanographic applications. The attendee will gain basic understanding of AUV types, technologies, terminology, and navigation techniques, including discussion of the comparative strengths of AUVs and alternative methods of data collection. The attendee will also be provided an understanding of tradeoffs in AUV operations, including power estimation, endurance considerations, and mission structure to acquire the desired data sets. Key points are illustrated by applications and results from the Monterey Bay Aquarium Research Institute’s (MBARI) Dorado AUV and other AUV operations. Topics include: Basic AUV technology, AUV at-sea Operation, Payload Considerations, Mission Planning, Upper and Mid-Water AUV missions, Benthic and Mapping AUV missions, Data Collection and Reduction, AUV Integration into Sampling Networks, and a look at coming AUV advances. The interactive format, using the materials provided, allows the attendee discussion time for relevance and demonstration purposes regarding real or potential AUV plans.
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Biography
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Bill is a Senior Research and Development Engineer at the Monterey Bay Aquarium Research Institute (MBARI) located in Monterey Bay, California. Bill has a BS in Mechanical Engineering and a MS in Computer Science which he has applied to controls and automation of electromechanical systems and robotics since 1978. Bill has been with MBARI for 19 years as a lead mechanical engineer and program manager developing the Tiburon remotely operated vehicle and Dorado class autonomous underwater vehicles. Bill’s current focus is development of underwater instrumentation for science studying hydrates and ocean acidification issues associated with anthropogenic CO2.
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Please direct enquiries regarding the tutorials program to the Chair of Tutorials, Prof. Peter Gough: |
