| Exploitation of Environmental Complexity in Shallow Water Acoustic Data Communications |
27-Mar-2009 |
8 pages |
| Authors:
William S Hodgkiss; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA VISIBILITY LAB
|
 | Complexity of the channel is beneficial for time reversal communications. After multichannel combining, each user signal is processed with a single channel decision feedback equalizer (DFE) to remove any residual intersymbol interference (ISI) and compensate for channel fluctuations during the packet transmission. This same approach can be applied in a synthetic aperture context where multiple transmissions (separated spatially) substitute for multiple receive elements. As an alternative to the passive time ... |
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| Multi-Static Detection and Localization of Buried Targets using Synthetic Aperture Iterative Time-Reversal Processing |
18-Mar-2009 |
26 pages |
| Authors:
H C Song; Karim Sabra; W A Kuperman; W S Hodgkiss; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| The objective of this project is to develop bi-static applications of the iterative time reversal techniques to focus along the ocean bottom. Iterative time-reversal provides a simple solution for self-adaptive focusing on strong reflectors (i.e. scattering targets) located on the ocean bottom without relying on predictive or modeling capabilities of the environment and of the target of interest. These robust focusing properties are crucial for mapping large and uncharted areas ... |
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| Acoustic and Visual Monitoring for Cetaceans Along the Outer Washington Coast |
01-Mar-2009 |
45 pages |
| Authors:
John Calambokidis; Greg Schorr; Erin Falcone; Erin M Oleson; John A Hildebrand; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
|
| Since July 2004, visual and acoustic monitoring efforts for marine mammals have been conducted in waters off the outer Washington coast. These efforts have been specifically to determine the seasonal occurrence of marine mammal species and to estimate their relative abundances, particularly in the area of the proposed expansion of the U.S. Navy's Quinault Underwater Tracking Range (QUTR) of the Northwest Range Complex. This has resulted in the first multi-year, ... |
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| Automated Detection of a Crossing Contact Based on Its Doppler Shift |
Mar-2009 |
117 pages |
| Authors:
Whye Kaong How; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The trade-off between false alarm and detection probability is a fundamental challenge in the automated detection of contacts in passive sonar systems. A common approach is the application of high gain processing followed by successive classification criteria. Most classification schemes (e.g., matching of signature) are complex and tailored to specific target types. By contrast, the Doppler effect is readily observed in all contacts with discrete tonals and relative velocity to ... |
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| Undersea Node Localization Using Node-to-Node Acoustic Ranges in Distributed Seaweb Network |
Mar-2009 |
116 pages |
| Authors:
David C Zinkhon; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Seaweb is a wide-area network interconnecting a set of distributed underwater nodes through the use of a DSP-based acoustic communications modem at each node and through-water digital acoustic links between neighboring nodes. As a by-product of Seaweb communications, the distances between neighboring nodes are obtained from the roundtrip acoustic travel-time measurements. If the network is deployed in an ad hoc distribution, or if an established network is disturbed, the locations ... |
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| Performance Enhancements of Ranging Radio Aided Navigation |
Mar-2009 |
76 pages |
| Authors:
Patric J Ernsberger; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| To accomplish Navigation in areas denied Global Navigation Satellite System (GNSS), such as around buildings or in steep valleys, alternative methods must be used. Radio ranging systems have been a part of the navigation solution for years. To improve the position estimate it is believed that using vision, consumer grade inertial navigation systems, and any other measurement available can aid the navigation solution. To accomplish this, an extended Kalman filter ... |
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| Portable Ultrasound Imaging of the Brain for Use in Forward Battlefield Areas |
Mar-2009 |
21 pages |
| Authors:
Gregory T Clement; ULTRADIAGNOSTICS INC ATTLEBORO FALLS MA
|
| Using ultrasound as a detection device in the body, including the brain, has been extensively investigated. Unfortunately, previous ultrasound-based methods on the brain have suffered from the severe distortion caused by the skull bone. The authors have recently developed a technique that allows ultrasound to propagate through the skull with significantly reduced distortion using a shear mode technique. The current project will develop a device for noninvasive identification of the ... |
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| The N456 Navigator System |
Jan-2009 |
52 pages |
| Authors:
Lane J Abrams; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| The N456 Navigator has been developed to assist in Long Baseline (LBL) acoustic navigation. Its two basic functions are generation of acoustic signals, and receipt and timing of returns. When combined with the new dsnav software this becomes the basic component of an LBL navigation system. The principal motivation for this development was as a replacement for the Benthos 455 Acoustic Signal Processor and the Alvin's NavBox. The N456 is ... |
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| Acoustic Image Models for Navigation with Forward-Looking Sonars |
Dec-2008 |
69 pages |
| Authors:
Masek; Theodore D Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Cost and miniaturization of autonomous unmanned vehicles (AUV) drive component reuse and better sensor data analysis. One such component is the forward looking sonar (FLS) which can be used for obstacle avoidance and to extract vehicle state information. However, autonomous feature extraction of images from the FLS is difficult due to the noise inherent in the sensor and the sensor's susceptibility to interference from other acoustic devices. This thesis investigated ... |
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| Assessing Potential Sites for Undersea Warfare Training Ranges: The Effects of Active Sonars on Marine Mammals |
28-Oct-2008 |
84 pages |
| Authors:
Yadira V Gilchrest; Thomas N Fetherston; Bert E Neales; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The U.S. Navy is preparing a draft environmental impact statement/overseas environmental impact statement (DEIS/OEIS) for what will be the proposed site for an undersea warfare training range (USWTR). The DEIS includes an assessment of the effects of Navy active acoustic sonars on marine mammals during range exercises as required by the Marine Mammal Protection Act (MMPA). The Naval Undersea Warfare Center Division, Newport, RI, has assessed four sites: Jacksonville, FL; ... |
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| Time-Dependent Stochastic Inversion in Acoustic Tomography of the Atmosphere with Reciprocal Sound Transmission |
17-Oct-2008 |
14 pages |
| Authors:
Sergey N Vecherin; Vladimir E Ostashev; A Ziemann; D K Wilson; NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS
|
| Time-dependent stochastic inversion (TDSI) was recently developed for acoustic travel-time tomography of the atmosphere. This type of tomography allows reconstruction of temperature and wind-velocity fields given the location of sound sources and receivers and the travel times between all source?receiver pairs. The quality of reconstruction provided by TDSI depends on the geometry of the transducer array. However, TDSI has not been studied for the geometry with reciprocal sound transmission. This ... |
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| Littoral Drifter for Sensing Properties of Shallow Waters and Sediments: Riverine Drifter Field Trials July 10, August 13 and September 10, 2008 |
08-Oct-2008 |
70 pages |
| Authors:
W G Williams; Luca Centurioni; CLEARWATER INSTRUMENTATION INC WATERTOWN MA
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| Shallow water environments that exist where rivers and estuaries meet the ocean are often characterized by regimes of energetic currents and shallow rapidly varying bathymetry which in the case of easily mobilized sediments can by spatially modified over short periods. The Riverine drifter has the observational tools to measure the characteristics of the estuarine environment. It combines the position accuracy of GPS locations, 3-dimensional current measuring ability of an Acoustic ... |
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| The Sonar Simulation Toolset, Release 4.6: Science, Mathematics, and Algorithms |
01-Oct-2008 |
123 pages |
| Authors:
Robert P Goddard; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
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| The Sonar Simulation Toolset (SST) is a computer program that produces simulated sonar signals, enabling users to build an artificial ocean that sounds like a real ocean. Such signals are useful for designing new sonar systems, testing existing sonars, predicting performance, developing tactics, training operators and officers, planning experiments, and interpreting measurements. SST's simulated signals include reverberation, target echoes, discrete sound sources, and background noise with specified spectra. Externally generated ... |
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| Stress Analysis of the Lifting Fixture Used in the 2008 Conformal Sonar Array Trials at Seneca Lake |
01-Sep-2008 |
29 pages |
| Authors:
NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| Detailed stress analyses were required of critical lifting fixture components used to support conformal sonar array assemblies in performance trials conducted in 2008 at the Naval Undersea Warfare Center's Seneca Lake Test Facility. The stress analyses were necessary to ensure that the lifting fixture had sufficient structural integrity for the handling and operational phases of the trials. The targeted structural integrity levels required compliance with a minimum safety factor for ... |
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| Comparison of Linear and Nonlinear Processing with Acoustic Vector Sensors |
01-Sep-2008 |
92 pages |
| Authors:
Skevos T Psaras; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Towed arrays of vector sensors are currently being employed in a variety of naval applications. The use of acoustic vector sensors, which measure the acoustic pressure and three orthogonal axes of associated particle motion, are of interest because of the signal gain and additional directionality achievable. The majority of analysis performed on vector sensor arrays has involved the advantages of conventional (linear) standard cardioid beamform processing. In this work, we ... |
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| Acoustic Scattering from Sand Dollars (Dendraster excentricus): Modeling as High Aspect Ratio Oblate Objects and Comparison to Experiment |
Sep-2008 |
162 pages |
| Authors:
Gregory C Dietzen; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| Benthic shells can contribute greatly to the scattering variability of the ocean bottom, particularly at low grazing angles. Among the effects of shell aggregates are increased scattering strength and potential subcritical angle penetration of the seafloor. Sand dollars (Dendraster excentricus) occur commonly in the ocean and have been shown to be significant scatters of sound. In order to understand more fully the scattering mechanisms of these organisms, the scattering from ... |
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| Scattering from inclusions in Marine Sediments: SAX04 Data/Model Comparisons |
14-Jul-2008 |
77 pages |
| Authors:
Anatoliy N Ivakin; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| The role of discrete scatterers in marine sediments is evaluated based on acoustic and environmental measurements at the shallow water sediment acoustics experiment, SAX04, and shown to be significant. The sediment at SAX04 site was complicated and characterized as a mostly medium sand / mud mixture. Analysis of the sediment samples showed presence of a small volume portion of arger particles, such as coarse sand fraction and shell fragments, which ... |
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| Characterization of the MEMS Directional Sound Sensor Fabricated Using the SOIMUMPS Process |
01-Jun-2008 |
113 pages |
| Authors:
Antonios Dritsas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A micro-electro-mechanical system (MEMS) based directional sound sensor performance is characterized. The operation of directional sound sensor is based on the hearing organ of Ormia ochracea fly, which uses coupled bars hinged at the center to achieve the directional sound sensing. The MEMS sensor design considered in this thesis is fabricated using a process by which the sensor has two resonant vibrational modes: rocking and bending. The sensor is simulated ... |
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| Novel High Frequency Signatures for Classification/Identification |
01-Jun-2008 |
|
| Authors:
Philip L Marston; WASHINGTON STATE UNIV PULLMAN DEPT OF PHYSICS
|
 | The emphasis of the research summarized here concerns the production of enhancements in the scattering of high frequency sound by various penetrable cylinders. Examples of such cylinders in water include solid polymer (plastic) cylinders having flat or curved ends, plastic cylindrical shells containing a liquid having a low speed of sound, and a solid fiberglass cylinder. In some cases the cylinders were encased in stainless steel or fiberglass. In most ... |
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| Sinusoidal Vertical Motion of a Sonobuoy Suspension: Experimental Data and a Theoretical Model |
Jun-2008 |
36 pages |
| Authors:
David M F Chapman; Dusko B A Kezele; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| To isolate its acoustic sensor from the large vertical motions of the buoy at the ocean surface, a typical sonobuoy employs a low-pass mechanical filter comprising a bungee cord (spring) and a damper disk (hydrodynamic added mass and damping). If the system were to behave as a driven simple harmonic oscillator, the transfer function of vertical motion would roll off at 40 dB/decade above resonance; however, experimental systems of this ... |
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| A Mathematical Model for the Acoustic and Seismic Properties of the Landmine Detection Problem |
06-May-2008 |
119 pages |
| Authors:
Michelle B Mattingly; NAVAL ACADEMY ANNAPOLIS MD
|
| Acoustic landmine detection is accomplished by using a loud speaker to generate airborne source low-frequency waves that are transmitted to the soil above a buried landmine target. At a specific frequency, the landmine will "vibrate" at resonance, imparting an enhanced velocity on the soil particles above it at the surface that is detected by a scanning Laser Doppler Vibrometer system. If the soil surface velocity profiles measured from these experiments ... |
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| Center for Coastline Security Technology, Year 3 |
01-May-2008 |
298 pages |
| Authors:
Stewart Glegg; R Granata; P Ananthakrishnan; K vonEllenrieder; S Schock; G Frisk; P Beaujean; Borko Furht; William Glenn; R Coulson; FLORIDA ATLANTIC UNIV BOCA RATON COLL OF ENGINEERING
|
| The Center for Coastline Security Technology (CCST) focuses on research, simulation, and evaluation of coastal defense and marine domain awareness equipment, sensors and components. It builds upon the existing efforts and expertise in coastal systems and sensor research at the Institute for Ocean and Systems Engineering (IOSE), the Imaging Technology Center, and the Department of Computer Science at Florida Atlantic University. New technologies are needed to enhance surveillance and inspections ... |
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| Development and Evaluation of a Virtual Terrain Board for Night Vision Goggle Training |
18-Mar-2008 |
42 pages |
| Authors:
DeForest Q Joralmon; Jeanette M Dunham; Christina J Price; L3 COMMUNICATIONS MESA AZ
|
| This report describes the development and evaluation of the Night Readiness, LLC Virtual Terrain Board (VTB) (V2.0c) and its instructional modules for NVG ground training. The evaluation consisted of a training effectiveness assessment of the VTB, using feedback from qualified NVG Training Course terrain board instructors and students undergoing refresher training and students attending initial NVG ground training at six military VTB installations. The primary objectives of the training effectiveness ... |
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| Sensor Performance Evaluation for Battlefield Environments (SPEBE) C++ Application Programming Interface (API) Version 1.0 |
01-Jan-2008 |
104 pages |
| Authors:
David Marlin; Shane Thomas; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM COMPUTATIONAL AND INFORMATION SCIENCE DIRECTORATE
|
| In this report, a C++ library based on a compiled version of the Matlab-based Sensor Performance Evaluator for Battlefield Environments (SPEBE) is described. The library encapsulates the details of the Matlab infrastructure, including m-files and mxArray manipulation functions, so that the programmer can concentrate on the use of SPEBE rather than the details of compiled Matlab code. The high-level architecture of SPEBE is duplicated in the C++ class hierarchy, providing ... |
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| Free Electron Laser Performance with Quadruple Magnet Misalignment from Shipboard Vibrations |
01 DEC 2007 |
79 pages |
| Authors:
David T. Burggraff; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Free Electron Laser (FEL) has been discussed and studied in the United States Navy s directed energy weapon efforts. The goal of these studies is to use the FEL as a ship s primary defensive weapon against incoming threats such as missiles, aircraft and small boats. This thesis is an analysis of the effects of shipboard vibration on the performance of an FEL. The focus of this analysis will ... |
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| Non Linear Internal Waves: Modeling of Their Influence on Acoustic Mode Energy Fluctuations and Characterization Using SAR Systems |
DEC 2007 |
111 pages |
| Authors:
Alban Simon; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Non Linear Internal Waves (NLIW) are ubiquitous and appear wherever a proper combination of stratified water, current and bathymetry occur. In recent years, they have also been proven of primary interest for acoustic oceanography, since they are known to play an important role in sound speed fluctuations in shallow waters. The predictability of acoustic variability caused by these waves has been somewhat limited, and largely based on direct numerical simulation. ... |
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| 3D Underwater Imaging Using Vector Acoustic Sensors |
Dec-2007 |
8 pages |
| Authors:
Dennis Lindwall; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
|
| Marine surveys that use vector acoustic sensors may allow for 3D imaging of underwater environments with a much smaller amount of data than current 3D hydrophone surveys. Newly developed sensors make vector-acoustic-based surveys practical. This concept is demonstrated with data from a three-axis accelerometer and a collocated hydrophone in an acoustic water tank using a short-pulse source and passive scattering targets. One algorithm rectifies the vector data with scalar pressure ... |
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| The Use of SIG Algorithms in Sea Tests |
28 NOV 2007 |
12 pages |
| Authors:
Lawrence Carin; Patrick Rabenold; SIGNAL INNOVATIONS GROUP INC DURHAM NC
|
| This report summarizes recent progress by Signal Innovations Group (SIG) in supporting the Naval Research Laboratory (NRL) on the development and application of mine identification algorithms using a Low Frequency Broadband (LFBB) sonar system. SIG has the tasks of developing the algorithms and transitioning them to NRL for use in sea tests. Fully-transitioned algorithms have performed well in sea tests, with additional development increasing the computational efficiency. The discussion below ... |
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| False Indicators to Acoustic-To-Seismic Buried Landmine Detection |
28 NOV 2007 |
29 pages |
| Authors:
James M. Sabatier; MISSISSIPPI UNIV UNIVERSITY NATIONAL CENTER FOR PHYSICAL ACOUSTICS
|
| The proliferation of relatively cheap landmines in many of the world's conflicts has led to a critical situation. Most methods of locating landmines trigger on too many false alarms must each be investigated before declaring an area to be clear of mines. This led to the need for an accurate means of detection coupled with a low false alarm rate. The University of Mississippi has developed an acoustic/seismic technique to ... |
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| Shallow Water MCM and ASW Using Off-Board, Autonomous Sensor Networks and Multistatic, Time-Reversal Acoustics |
16 NOV 2007 |
8 pages |
| Authors:
H-C Song; P. Gerstoft; W. A. Kuperman; W. S. Hodgkiss; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| This was a joint project with MIT, Henrik Schmidt et al "separate ONR proposal" and SACLANTCEN "Stevenson and Jensen". The long term goals are to develop environmentally adaptive bi- and multi-static sonar concepts for autonomous off-board sensor networks for the detection and classification of proud, buried and waterborne targets in shallow water. SACLANTCEN provided three weeks of simultaneous sea time for both the R/V Alliance and R/V Leonardo during July ... |
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| Computer Assisted Cancer Device -- 3D Imaging |
31-Oct-2007 |
8 pages |
| Authors:
Michael Liebman; Kevin Woods; Albert V Porambo; JACKSON (HENRY M) FOUNDATION ROCKVILLE MD
|
| It is well documented that breast cancer is frequently missed on mammograms, leading to delayed detection and potentially less successful treatment. Our studies show that approximately 32% of cancers can be detected early using mammograms. While current Computer-Assisted Detection (CAD) technology is designed to capture as many of these cancers as possible, it is not able to offer information specific enough to assist the radiologist in determining the best course ... |
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| Measuring the Spatial Distribution of Ripples Using REMUS AUV |
10 OCT 2007 |
|
| Authors:
Wayne R. Geyer; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The long term goal of this work is to increase our understanding of bedform geometry and processes associated with bedforms on the continental shelf. To do this we have been developing novel measurement techniques, conducting observations of both the spatial and temporal variability of ripples and developing a variety of model approaches. |
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| Statistical Characterization of Fish School Clutter |
OCT 2007 |
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| Authors:
Timothy K. Stanton; Dezhang Chu; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| To significantly reduce the probability of false alarm in Navy active sonar systems. This goal will be achieved through developing signal algorithms for active sonar systems which can account for the non-Rayleigh nature of clutter from fish schools. Part of this goal will involve characterizing the performance of the algorithm. |
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| Tracking Targets of Interest Via Acoustics |
OCT 2007 |
18 pages |
| Authors:
Latasha Solomon; Duong Tran-Luu; ARMY RESEARCH LAB ADELPHI MD
|
| Current military operations require robust signal-processing algorithms that allow for hostile fire defeat in reverberant environments. These algorithms must provide the individual Soldier with real-time situational awareness and actionable intelligence. Sensor configuration, terrain features, and atmospheric conditions must be considered when one is developing such algorithms. This report analyzes localization results of a novel signal-processing technique used to localize and track acoustic mortar data during a recent field experiment. |
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| Using Range and Range Rate for Relative Navigation |
05 SEP 2007 |
38 pages |
| Authors:
Brian S. Bourgeois; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOSCIENCES DIV
|
| This report documents an investigation into the use of range and range rate as an approach for navigating an underwater vessel relative to another vessel for formation maneuvering tasks. Range and range rate between underwater vehicles can be estimated using elapsed time and Doppler shift measurements done by modern acoustic modems. This approach has the potential to allow coordinated team maneuvering using existing vehicle communications without the need for offboard ... |
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| Tomographic Reconstruction of Atmospheric Turbulence with the Use of Time-Dependent Stochastic Inversion |
01-Sep-2007 |
11 pages |
| Authors:
Sergey N Vecherin; Vladimir E Ostashev; A Ziemann; D K Wilson; K Arnold; M Barth; NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS
|
| Acoustic travel-time tomography allows one to reconstruct temperature and wind velocity fields in the atmosphere. In a recently published paper [S. Vecherin et al., J. Acoust. Soc. Am. 119, 2579 (2006)], a time-dependent stochastic inversion TDSI was developed for the reconstruction of these fields from travel times of sound propagation between sources and receivers in a tomography array. TDSI accounts for the correlation of temperature and wind velocity fluctuations both ... |
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| Investigation of the Impact of Sonar Transmission on Fisheries and Habitat in the U.S. Navy's USWTR: Summary of Stakeholder Concerns and Appropriate Research Areas |
SEP 2007 |
30 pages |
| Authors:
Andrew Read; Elliott Hazen; DUKE UNIV BEAUFORT NC MARINE LAB
|
| Public comments responding to the Draft Environmental Impact Statement (October 2005) for the proposed Undersea Warfare Training Range (USWTR) off North Carolina were analyzed to provide a comprehensive view of stakeholder concerns. Three main areas of public concern -- short- and long-term effects on fish from mid-frequency sonar operations, displacement of fishermen during training exercises, and habitat modification/destruction -- were identified. Research areas that might address these concerns also were ... |
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| Research Required to Understand the Impact of Tactical Mid-Frequency Sonar Transmission on Fish, Fisheries and Fisheries Habitat: Summary of Stakeholder Concerns and Prioritized Research Plan from the Workshop on Mid-Frequency Sonar and Marine Fishes |
SEP 2007 |
26 pages |
| Authors:
Andrew Read; Elliott Hazen; Lucie Hazen; Lesley Thorne; DUKE UNIV BEAUFORT NC MARINE LAB
|
| As reported in NPS-OC-07-004, analysis of public comments responding to the Draft Environmental Impact Statement (October 2005) for the proposed Undersea Warfare Training Range (USWTR) in Onslow Bay off North Carolina identified three main areas of public concern. One of these concerns, the effects on fish and fisheries habitats of mid-frequency active (MFA) sonar, further identified four sub-areas of concern: catch rates, spawning choruses, distribution and migratory behavior, and physiological ... |
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| 2006 Progress Report on Acoustic and Visual Monitoring for Cetaceans along the Outer Washington Coast |
AUG 2007 |
30 pages |
| Authors:
Erin M. Oleson; John A. Hildebrand; John Calambokidis; Greg Schorr; Erin Falcone; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
|
| An acoustic and visual monitoring effort for cetaceans was initiated within the boundaries of the proposed expansion area for the Quinault Underwater Tracking Range in July 2004. Acoustic data collection consisted of recordings at a site on the continental shelf to the west of Cape Elizabeth and another in deep water within Quinault Canyon. An analysis plan for acoustic data is included. Results for 32 visual surveys are presented as ... |
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| An Operator Perspective on Net-Centric Underwater Warfare |
12 JUL 2007 |
|
| Authors:
Garfield R. Mellema; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| In March 2007, the Networked Underwater Warfare Technology Demonstration Project at Defence R&D Canada - Atlantic conducted an at-sea antisubmarine trial utilizing Net-centric Warfare (NCW) constructs to demonstrate improved technologies for underwater warfare. User feedback was solicited during and after the trial for the purpose of documenting the manner in which the systems were used during the trial and gaining insight into their potential future usage in NCW activities. This ... |
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| Correlation Based Testing for Passive Sonar Picture Rationalization |
10 JUL 2007 |
|
| Authors:
Garfield R. Mellema; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| Modern passive sonar systems employ a high degree of automation to produce a track-level sonar picture. Further refinement of the track-level information is normally performed by a human operator. Providing automated assistance would reduce the operator's workload and is a key enabler for semi and fully automated sonar systems. The nature of the signals emitted by targets and of the underwater environment typically results in each target being represented by ... |
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| Spatial Averaging of Oceanic Rainfall Variability Using Underwater Sound. Ionian Sea Rainfall Experiment 2004: Acoustic Component |
JUL 2007 |
47 pages |
| Authors:
Jeffrey A. Nystuen; Eyal Amitai; Emmanuel N. Anagnostou3; Marios N. Anagnostou; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| An experiment to evaluate the inherent spatial averaging of the underwater acoustic signal from rainfall was conducted in the winter of 2004 in the Ionian Sea southeast of the coast of Greece. A mooring with four passive aquatic listeners (PALs) at 60, 200, 100, and 2000 m was deployed at 36.85 deg. N, 21.52 deg. E, 17 km west of a dual-polarization X-band coastal radar (XPOL) at Methoni, Greece. A ... |
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| Array Plate Apparatus Having Tunable Isolation Characteristics |
26 JUN 2007 |
24 pages |
| Authors:
Neil J. Dubois; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| It is therefore a primary object and general purpose of the present invention to provide an apparatus for use on an underwater vehicle in which the apparatus significantly reduces the amount of vehicle self-noise that travels to an array plate of the undersea vehicle. It is a further object of the present invention to significantly reduce the noise floor at which acoustic transducers operate. An apparatus having an array plate ... |
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| Analyzing the Performance of Multi-hop Underwater Acoustic Sensor Networks |
01-Jun-2007 |
7 pages |
| Authors:
Hui Chen; Geoffrey G Xie; Yang Xiao; John H Gibson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF COMPUTER SCIENCE
|
| Multi-hop underwater acoustic sensor networks constrain the performance of medium access control protocols. The efficiency of the well-known RTS-CTS scheme is degraded due to long propagation delays of such networks. Recently, interest in Aloha variants has surfaced; however, the performance of such protocols within the context of multi-hop networks is not well studied. In this paper, we identify the challenges of modeling contention-based medium access control protocols and present a ... |
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| Acoustic Tomography of the Atmosphere |
31 MAY 2007 |
16 pages |
| Authors:
V. E. Ostashev; G. H. Goedecke; NEW MEXICO STATE UNIV LAS CRUCES
|
| In this project, theoretical foundations for construction and operation of the state-of-the-art array for acoustic tomography of the atmosphere were developed. (The array was built at the Boulder Atmospheric Observatory under the ARO sponsorship, project DAAD19-03-1-0341.) First, the travel times of sound propagation between different pairs of sources and receivers of the array were expressed in terms of the temperature and wind velocity fields within the tomographic volume. Then, a ... |
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| Nonlinear Acoustic Landmine Detection: Profiling Soil Surface Vibrations and Modeling Mesoscopic Elastic Behavior |
04 MAY 2007 |
122 pages |
| Authors:
Sean A. Genis; NAVAL ACADEMY ANNAPOLIS MD
|
| Acoustic-to-seismic (A/S) coupling involving airborne sound is used to generate soil vibrations that interact with the top plate of a buried landmine. Due to scattering, the interaction at the soil-mine interface produces an enhanced and strongly nonlinear soil surface vibration directly over the buried landmine. Resonant tuning curves of the soil-mine system show that the nonlinear behavior observed near resonance for "on the mine" locations is considerably stronger than that ... |
|
| Center for Coastline Security Technology, Year-2 |
01 MAY 2007 |
280 pages |
| Authors:
Stewart Glegg; William Glenn; Borko Furht; P. P. Beaujean; G. Frisk; S. Schock; K. VonEllenrieder; P. Ananthakrishnan; E. An; R. Granata; FLORIDA ATLANTIC UNIV BOCA RATON
|
| The Center for Coastline Security Technology (CCST) focuses on research, simulation, and evaluation of coastal defense and marine domain awareness equipment, sensors, and components. It builds upon the existing efforts and expertise in coastal systems and sensor research at the Institute for Ocean and Systems Engineering (IOSE), the Imaging Technology Center, the Department of Computer Science and Engineering, and the University Consortium for Intermodal Transportation Safety and Security at Florida ... |
|
| Improving Air Force Active Network Defense Systems through an Analysis of Intrusion Detection Techniques |
01-May-2007 |
39 pages |
| Authors:
David R Dunklee; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The main objective of this research is to highlight real world and exercise events that indicate our technologies, techniques, and processes for active network defense need to be improved. The research then presents four recommendations to improve DCC operations. These include: Transition or improve the current signature-based IDS systems to include the capability to query and visualize network flows to detect malicious traffic; re-dedicate training and OPTN efforts to fully ... |
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| Measurements and Analysis of Reverberation and Clutter Data |
APR 2007 |
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| Authors:
Dale D. Ellis; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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| This report describes the objectives and some of the results from a three-year joint collaboration between DRDC Atlantic and the Applied Research Laboratory of The Pennsylvania State University to analyze and model reverberation data. Reverberation data up to 4 kHz had been collected on towed arrays during the initial (1996 2002) NATO MILOC Rapid Environmental Assessment exercises and more recent JRPs (Joint Research Projects) between the US, Canada, and SACLANTCEN ... |
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| Sonar 3 VMSA Federate: User Guide and Technical Description |
APR 2007 |
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| Authors:
Allan Gillis; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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| This federate provides a medium fidelity sonar model for Virtual Maritime Systems Architecture (VMSA) high level architecture (HLA) simulations. The model best represents towed array systems, but can be configured to model flank arrays as well. The Sonar model is coupled with an auto-detector/signal follower that creates VMSA Sonar tracks without an operator. While the federate is written in Java, the signal follower is provided only as a compiled Windows ... |
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Acoustic Detection and Detectors
