| 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
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 | 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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| Low Frequency Sonar Countermeasure |
09 MAR 2005 |
17 pages |
| Authors:
Thomas A. Frank; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A multi-port projector of acoustic energy in water includes a cylindrical hollow transducer having open annular ends. A thin, flexible member is secured to each annular end to extend across each opening to be displaced by the transducer, and the transducer and flexible members form an interior sealed from ambient water. A battery/electronics module is in the interior and is spaced from the transducer and flexible members to couple driving ... |
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| Self Adjusting Neutral Buoyancy Countermeasure and System |
10 OCT 2001 |
24 pages |
| Authors:
Neil J. Dubois; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An underwater self adjusting displacement device includes a sealed housing having an exterior wall and an inner component area, the exterior wall having an opening formed therein. A sealing plug is slidably seated in the opening of the exterior wall, and an actuator mechanism selectively adjusts the sealing plug within the opening, thereby adjusting a total displacement of the sealed housing. The displacement device is incorporated into any substantially neutrally ... |
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| Space-Time Adaptive Matched-Field Processing (STAMP) |
14 MAR 2001 |
8 pages |
| Authors:
Yung P. Lee; SCIENCE APPLICATIONS INTERNATIONAL CORPMCLEAN VA
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| Space-time adaptive processing (STAP) is two-dimensional adaptive filter employed for the purpose of clutter cancellation to enable the detection of moving targets. It has been a major focus of research activity in radar applications for which the platform is in motion (e.g., airborne or space-based systems). In this setting, an antenna sensor array provides spatial discrimination, while a series of time returns or pulses form a synthetic array that provide ... |
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| Ambient Noise Characteristics During the Sheba Experiment |
MAR 2000 |
121 pages |
| Authors:
Ronald R. Shaw Jr.; OFFICE OF NAVAL RESEARCH ARLINGTON VA
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| The ambient noise data recorded by two free-drifting buoys during the 1997-98 SHEBA experiment presented a unique opportunity to gauge the noise field of the Arctic Ocean in a unique and changing environment. The two buoys drifted in unison for 12 months, providing an hourly ambient noise data set between 50 and 1000 Hz. The drift pattern was divided into five legs in response to the season ... |
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| Acoustic Sensing Countermeasure Device and Method of Determining a Threat Direction |
28 FEB 2000 |
15 pages |
| Authors:
Gerald T. Stevens; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An acoustic sensing countermeasure device is used to sense the direction of a threat projectile or vehicle in addition to countering the threat with noise or interference signals. Countermeasure device includes an acoustic receive array comprised of segmented vertical slaves preferably mounted within a reduced diameter section around the outside housing of the countermeasure device. The staves are grouped to form directional acoustic beams across the entire horizontal plane. To ... |
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| Ship Wake Signature Suppression. |
28 JUL 1998 |
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| Authors:
Matthew J. Sanford; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A method is presented to reduce the quantity of microbubbles having diameters of approximately 1000 microns or less in seawater as a means of ship wake signature suppression. Ultrasonic acoustic energy is projected into a volume of seawater in which the microbubbles reside. e.g.. a ship's wake. The ultrasonic acoustic energy has a constant frequency selected from the range of approximately 0.5-2.5 MHz. |
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| New AOTF Technology for IR Hyperspectral Imaging |
03 MAR 1998 |
14 pages |
| Authors:
Vladimir Pelekhaty; Xiaolu Wang; Duane E. Paulsen; BRIMROSE CORP OF AMERICA BALTIMORE MD
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| We have developed a new Acousto-Optic Tunable Filter (AOTF) for implementation as a spectrally selective element for hyperspectral imaging applications in the NIR (.8 - 1.7 micron) and MWIR (2.5 - 4.5 micron) ranges of the optical spectrum. The new AOTF has high spectral resolution (about 3/cm) and requires relatively low RF drive power. It has a broad acceptance angle and increased diffraction efficiency for enhanced optical throughput. In combination ... |
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| Field Trial Evaluation of the CRC Adaptive-Antenna Algorithm for the NATO STANAG 4285 Waveform |
DEC 1997 |
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| Authors:
K. H. Wu; A. Tenne-Sens; COMMUNICATIONS RESEARCH CENTRE OTTAWA (ONTARIO)
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| Results are presented for the evaluation of an adaptive-antenna algorithm designed for the NATO STANAG 4285 PSK (phase-shift keyed) waveform. The algorithm was developed at the Communications Research Center and has been implemented on both the Andrew SciComm HF Adaptive-Antenna Receiving System (HFAARS or AN/FRQ-26) and the SED Systems Programmable HF Adaptive Receiving System (PHFARS); the tests reported here were conducted using the Andrew HFAARS. The goal was to evaluate ... |
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| Microwave Nondestructive Evaluation of Disbonds Under Anechoic Tiles |
JUL 96 |
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| Authors:
R. J. Ditchburn; A. Amiet; S. K. Burke; DEFENCE SCIENCE AND TECHNOLOGY ORGANIZATION CANBERRA (AUSTRALIA)
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| An experimental and theoretical study of a microwave nondestructive inspection technique to detect the presence of and evaluate the thickness of disbonds between anechoic tiles and the hull of the COLLINS class submarine is presented. The magnitude and phase of a reflected microwave signal in the absence and presence of a disbond is measured as a function of disbond thickness and frequency for (i) a layer of anechoic tile material ... |
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| Decoy. |
27 FEB 1996 |
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| Authors:
G. C. Carter; Philip G. Clarke; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A decoy capable of assuring the shape of a water craft comprises a maneuverable vessel, having a tubular body portion which defines an enclosed interior region. The vessel further has an opening formed in the body portion and a hatch door which covers the opening. An energy source powers the operation of the vessel, and a drive module propels the vessel under the water. A selectively deployable bladder is stored ... |
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| Modeled High-Frequency Acoustic Backscattered Levels from Range- Independent and Simplistic Range-Dependent Sand Bottoms |
21 FEB 96 |
17 pages |
| Authors:
Kristen D. Savage; Roger W. Meredith; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Results investigating the effects of variable bottom composition on modeled high-frequency backscattered levels are presented for a typical shallow- water, variable bottom (range-dependent) environment. The modeled environment consisted of a single sound speed profile, a flat sea bottom with range- dependent bottom composition, and a smooth, flat sea surface. Coarse-and fine- grained sandy areas were partitioned in range to create range dependence. Bottom backscattering and reflection loss for each partition ... |
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| Critical Sea Test |
1996 |
40 pages |
| Authors:
SPACE AND NAVAL WARFARE SYSTEMS COMMANDWASHINGTON DC
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| In 1996, the Critical Sea Test (CST) Program completes a ten-year history of contributions to the use of Low-Frequency Active Acoustics (LFAA) in Undersea Warfare. The CST Program originated in Fiscal Year 1987 as a CNO Urgent Antisubmarine Warfare (ASW) Research and Development (R&D) Program (CUARP) initiative to counter the growing capability of the Soviet Navy to develop ever- quieter submarines. The program was initiated by the Space and Naval ... |
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| Active Acoustic Impedance Modification Arrangement for Controlling Sound Interaction. |
19 SEP 1995 |
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| Authors:
Robert D. Corsaro; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An active impedance modification device or arrangement enables the interaction of sound with a structural surface to be controlled, e.g., so that, reflections from that surface (which can be the hull of a submarine) are substantially reduced or eliminated. The device comprises a coating comprising an inner driver transducer layer in contact with the structural surface an outer receiver transducer layer which receives the sound, in combination with a variable ... |
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| Anechoic and Decoupling Coating. |
22 AUG 1995 |
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| Authors:
Maurice M. Sevik; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An anechoic and decoupling coating for use on the surface of an underwater structure for decoupling struc- tural vibrations from the water and for absorbing water- borne acoustic waves directed toward the structure from an external source such as a sonar. The coating is an elastomeric matrix containing sealed air-filled cavi- ties as well as random labyrinths of small water-filled passages running throughout and in open communica- tion with a ... |
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| Noise Control Composite. |
30 MAY 1995 |
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| Authors:
Eugene C. Fischer; Jean A. Montemarano; Vincent J. Castelli; Joseph W. Dickey; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A composite for use on submarines and surface craft for controlling self-generated noise when listening with sonar. The composite includes two layers of PVF2 transducers separated by a layer of phase shifting or absorbing material. The inner transducer senses noise from the ship and subtracts this from the signal from the outer transducer representing noise plus the desired signal. In a second mode the sensed noise is regenerated through the ... |
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| The New Age of Scientific Partnerships: Acoustic Capabilities and Facilities at NUWC Division, Newport -- Surface ASW Directorate Outlook |
29 SEP 94 |
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| Authors:
Peter D. Herstein; Joseph M. Monti; David G. Browning; NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV RI
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| A Vehicle Trajectory Method for Intercepting an Alerted, Evading Contact |
01 SEP 94 |
32 pages |
| Authors:
A. F. Bessacini; R. F. Pinkos; NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV RI
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| This report deals with the determination of a vehicle trajectory that will result in intercept of an alerted, evading contact. One of the classical problems associated with vehicle employment is the calculation of those parameters necessary for a vehicle trajectory to result in either intercept of a contact or for the vehicle to be delivered to a location that is suitable for the internal seeker system of the vehicle to ... |
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| Launched Torpedo Decoy. |
30 AUG 1994 |
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| Authors:
Robert C. Woodall Jr.; Kyle Jones; H. J. Jones Jr; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An acoustic decoy round ejected by a launcher for flight above water from a sea-going vessel, impacts at the water surface to cause separation of a payload from a forward section of the round that is also separated from a flotation anchor tethered to the payload and fins which stabilized launched flight of the round prior to impact. The separated payload submerges from the flotation anchor at the water surface ... |
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| Submarine Hull Structures Providing Acoustically Isolated Hull Openings. |
30 JUN 1994 |
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| Authors:
Paul E. Moody; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An acoustic isolation structure providing an acoustically isolated opening and comprising coaxial inner and outer annular structural members defining an irregular annulus between them. Acoustical isolation material is provided within this annulus to acoustically uncouple the two members. Radially overlapping structural rings extending from the members into the annulus limit lateral movement of the inner member and preserve the generally coaxial relation of the members. |
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| Pro-Submarine Mobile Decoy. |
28 SEP 1993 |
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| Authors:
Rudolph M. Haisfield; Homer D. Musselman; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An inexpensive decoy which simulates the evasive tactics of a submarine under attack for pulse echo type search systems and which can be ejected through the flare tube of a submarine. |
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| Expendable Moving Echo Radiator. |
01 SEP 1992 |
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| Authors:
Russell I. Mason; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An expendable moving echo radiator suitable for providing a decoy to attract a homing torpedo and divert the torpedo away from its intended target is disclosed. The present invention provides an expandable and collapsible curtain for deployment from a capsule launched from a submarine or other sea vessel. In its expanded configuration, the curtain is characterized by a physical profile sufficient to reflect acoustic waves and to generate echoes substantially ... |
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| Ultrasonic Ambient Noise in Australian Shallow Waters at Frequencies up to 200 kHZ |
FEB 92 |
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| Authors:
Douglas H. Cato; Michael J. Bell; MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA)
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| Little is known of ambient noise in the ocean at frequencies above 50 kHz and there are few measurements above 20 kHz. The results of this study indicate that the sustained ambient noise at frequencies up to 200 kHz in temperature and tropical waters of depths less than about 60 m is characterized by the numerous sharp transient sounds of snapping shrimps. These transients have pulse widths of typically 3 ... |
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| An Approach to Active Sonar Suppression Using a Dynamic Interference Model |
07 OCT 91 |
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| Authors:
Thomas F. Quatieri; Robert J. McAulay; Thomas Hanna; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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| This report summarizes preliminary work in the suppression of interfering active sonar for enhancement of underwater transients. The active sonar is modeled as an amplitude-modulated and frequency-modulated chirp signal. The estimation and suppression of the AM-FM chirp is performed in the framework of an analysis/synthesis technique that is based on a sine-wave representation of signals with components characterized by time-varying amplitudes, frequencies, and phases. Parameters of the chirp model, estimated ... |
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| Acoustic Mine Countermeasures. |
13 NOV 1990 |
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| Authors:
Louis A. Kish; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This patent discloses a mine sweeping method and related apparatus for achieving at least temporary passivation of underwater acoustic influence mines by the generation of particular underwater sounds of progressively increasing intensity. The water is acoustically pulsed by repetitively injecting into the water individual metered slugs of heated water, which water is heated to its saturation pressure but below the critical point. The metered slugs of heated water may be ... |
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| Acoustic Scattering by Near-Surface Inhomogeneities in Porous Media |
21 FEB 90 |
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| Authors:
Keith Attenborough; David L. Berry; Yu Chen; OPEN UNIV MILTON KEYNES (UNITED KINGDOM) FACULTY OF TECHNOLOGY
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| A theoretical and experimental investigation into the influence of near-surface buried inhomogeneities on the reflection of air-borne acoustic fields at a porous ground surface has been conducted based on the assumption that the ground supports only one wave type. Two theoretical treatments of this problem are presented, both involving reformulations of initial boundary value problems as boundary integral equations. Predictions of these formulations are compared with each other and with ... |
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| Transducer Needs for Low-Frequency Sonar |
90 |
28 pages |
| Authors:
R. W. Timme; A. M. Young; J. E. Blue; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
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| The continued advances in the acoustic quieting of submarines may necessitate the use of active sonar as an adjunct to the traditional passive sonar as a means of detecting submarines. Therefore, there is a growing need for transducers that produce sound underwater at frequencies below 1000Hz. However, reality is such that it is very difficult to design for low frequency, high power, and high efficiency and still maintain a device ... |
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| Safety Tests of ADC Mk 3 |
15 JAN 85 |
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| Authors:
R. F. Bis; J. Barnes; S. Buchholz; F. DeBold; P. Davis; NAVAL SURFACE WEAPONS CENTER SILVER SPRING MD
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| A technical evaluation and safety analysis have been conducted on an Acoustic Countermeasure ADC Mk 3. The ADC Mk 3 submarine decoy is stored on submarines between the pressure hull and outer hull. In the launch configuration a gas generator (containing a propellant) launches the decoy. However, in the shipping configuration the gas generator is separated from the launch container. The purpose of this report is to describe the results ... |
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| Wide Band Frequency Shifter in Variable Amounts. |
15 DEC 1981 |
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| Authors:
Keith E. Geren; Claude C. Routh; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The patent concerns a sonar decoy system for receiving and retransmitting any interrogating signal throughout a wide band of frequencies, said system comprising; a sonar receiver with a receiving hydrophone; a Sonar transmitter with a radiating transducer; a resolver with two orthogonal field coils, and a mechanically rotatable rotor coil; a first and a second network coupled between the output of said receiver and, respectively, said two field coils, said ... |
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| Artificial Underwater Target. |
29 APR 1980 |
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| Authors:
David J. Evans; Clark F. Bradley; DEPARTMENT OF THE NAVY WASHINGTON DC
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| In combination in a free, underwater craft, a hull, means for carrying ballast, means for discharging said ballast, depth responsive means, a timer providing two time intervals, control means operated by said timer for actuating said discharging means after a pre-set time interval, and other control means operated by both said timer and said depth responsive means for actuating said discharge means after a shorter time interval if said craft ... |
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| Submarine Simulating Sonar Beacon. |
15 APR 1980 |
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| Authors:
Peter Huisveld Jr.; Milton D. Papineau; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This invention relates generally to submarine boat simulating decoys and in particular to a sonar system for receiving the acoustical search pulse of an adverse or other vehicle and converting it into an elongated signal corresponding to the pulse that would be reflected from an actual maneuvering submarine boat and broadcasting said elongated signal back to said vehicle for deception and decoy purposes. In order to facilitate the training of ... |
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| Encoded Echo-Ranging Signal Generator. |
18 MAY 1976 |
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| Authors:
Daniel E. Andrews Jr.; William E. Klund; Robert D. Isaak; DEPARTMENT OF THE NAVY WASHINGTON D C
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| An object of the patent is to provide a method and means for generating a unique encoded signal that may be simultaneously used as a secure communication signal and target-ranging signal without one adversely interfering with the other. Another object is to provide a method and means for broadcasting a communication-echo-ranging sonar signal that has a random noise appearance to a casual observer or an eavesdropper not having the knowledge ... |
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| Selectable Up or Down Doppler Simulator. |
18 NOV 1975 |
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| Authors:
Peter Huisveld Jr.; Claude C. Routh; Milton D. Papineau; DEPARTMENT OF THE NAVY WASHINGTON D C
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| The object of the patent is to provide means for simulating a moving object in the sea. A doppler decoy receives a signal S and repeats the signal with a doppler frequency shift of S/K. |
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| Sonar Countermeasure. |
24 JUN 1975 |
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| Authors:
Rudolph M. Haisfield; DEPARTMENT OF THE NAVY WASHINGTON D C
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| The patent relates to a sonar countermeasure for use against active or passive sonar equipment. More specifically the patent relates to a countermeasure for active or passive torpedoes that home on sound sources. |
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| Models of Acoustic Deception and ASW Support in a Task Group Operating Area. |
DEC 1974 |
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| Authors:
J. R. Olmstead; T. R. Elfers; G. W. Black; STANFORD RESEARCH INST MENLO PARK CA NAVAL WARFARE RESEARCH CENTER
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| Three Markov models are developed and applied to some of the problems involving acoustic deception decoys and ASW forces. The scenario involves an enemy submarine searching for a high value unit in a large operating area. Several acoustic deception devices are randomly deployed in the area to draw the submarine's fire. One of the major conclusions of the study is that the effectiveness of acoustic decoys depends on whether or ... |
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| TRACOR's Mutual Interference, and Acoustic Countermeasures Analysis Capabilities. |
SEP 1974 |
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| Authors:
TRACOR INC AUSTIN TEX
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| Studies have been conducted on countermeasures susceptibility and on the effects of mutual interference (MI) for two surface ship sonar systems. Generally, the methods used to determine the effects of interference, whether countermeasures of mutual interference, are one or a combination of the following: (1) mathematical analysis, (2) computer simulation, and (3) psychophysical experimentation. Efforts have included such sonars as the AN/SQQ-23 (PAIR), the AN/SQS-26 AX, BX and CX, and ... |
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| Determine the Feasibility of Implementing Adaptive Echo Cancellation Techniques to Underwater Weapons |
09 NOV 1971 |
45 pages |
| Authors:
NAVAL ORDNANCE SYSTEMS COMMAND WASHINGTON DC
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| This document is aimed at determining the feasibility of implementing adaptive echo cancellation techniques to underwater weapons. |
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| A Submarine Barrier Detection Model, |
JAN 1971 |
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| Authors:
William T. McCormick Jr.; Alan W. Starr; INSTITUTE FOR DEFENSE ANALYSES ARLINGTON VA SYSTEMS EVALUATION DIV
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| The paper presents a model for calculating the maximum probability of detection of a submarine using a detection barrier of fixed length. It is assumed in this calculation that location and heading of the submarine are known to some degree of certainty. The barrier which is considered in this model could arise either from a single or multiplatform barrier operation or from a barrier of deployable acoustic sensors. (Author) |
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| Determination of Ship Course and Speed from Transmitted Signal Frequency. Addendum. |
24 APR 1967 |
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| Authors:
Richard A. Mueller; TRACOR INC SAN DIEGO CALIF
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| This report supplements TRACOR Report No. SD-67-0007-C, 'Determination of Ship Course and Speed from Transmitted Signal Frequency', dated 22 March 1967. The work of that report is extended here to cover the following two additional cases: surface vessel transmitting with full-doppler nullification but with broad beams instead of narrow; and surface vessel transmitting with half-doppler nullification and submarine utilizing side-lobe frequency information. |
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| Determination of Ship Course and Speed from Transmitted Signal Frequency. |
22 MAR 1967 |
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| Authors:
Richard A. Mueller; TRACOR INC AUSTIN TEX
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| In the design of the C/P Array Sonar, some consideration is being given to the use of an own-doppler-nullifier technique in which the transmitted frequency is varied according to the speed of the sonar vessel and the direction of the transmitted beam. The objective here is merely to determine if transmitting a frequency which is a function of own ship's course and speed furnishes a valuable additional clue which might ... |
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| Compasses, Odographs, Combat Acoustics, and Sonic Deception |
30 SEP 1946 |
202 pages |
| Authors:
OFFICE OF SCIENTIFIC RESEARCH AND DEVELOPMENT WASHINGTON DC
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Acoustic Countermeasures
