By Topic

Date 16-18 Sept. 1981

Filter Results

Displaying Results 1 - 25 of 252
  • [Front cover and table of contents]

    Publication Year: 1981, Page(s): 0
    Request permission for commercial reuse | PDF file iconPDF (2160 KB)
    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1981, Page(s): 0
    Request permission for commercial reuse | PDF file iconPDF (1131 KB)
    Freely Available from IEEE
  • Long-Baseline Deep Ocean Acoustic Tracking and Telemetry System

    Publication Year: 1981, Page(s):1 - 8
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    A portable, long-baseline acoustic tracking system incorporating an acoustic data telemetry link has been developed for deep ocean applications. The system is capable of tracking a surface ship and a submerged object with respect to a bottom-mounted transponder array to an accuracy of better than 10 m. Position updates of the ship and object along with data from the object are obtained every 15 to... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • CATEM, A Coherent Target and Environment Model for Sonar Analysis

    Publication Year: 1981, Page(s):9 - 15
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (629 KB)

    Major limitations exist in using conventional sonar analysis techniques to predict system performance. Insensitivity of these analysis procedures to signal phase, time delay and spatial effects may be of major concern. The Coherent Acoustic Target and Environment Model (CATEM) is designed to efficiently and accurately predict system performance. The model processes, in a digital manner, the signal... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time-Domain Theory Results in a Compact Scanning Sonar

    Publication Year: 1981, Page(s):16 - 20
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (611 KB)

    A compact within-pulse sector scanning sonar which is based on a time-domain approach and hence differs from conventional modulation scanning systems is described. A 32-input non-uniform time-delay-and-integrate charge coupled device has been designed and fabricated to implement the system. Experimental results are presented for a 500 KHz sonar scanning a 1 beam over a 30° sector at a scann... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Moving Source/Receiver Underwater Acoustic Tomography

    Publication Year: 1981, Page(s):21 - 25
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (366 KB)

    Remote sensing of the interior ocean environment by acoustic signals promises to be a cost effective approach to obtaining high resolution measurements over large areas. In this paper, an approach to remote sensing the interior sound speed of the ocean using historical sound speed data, spatially sparse sampling of sound speed at points within the ocean valume, and acoustic measurements is describ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Parabolic Equation Method Applied to an Ocean Duct with a Parabolic Index of Refraction Squared

    Publication Year: 1981, Page(s):26 - 30
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (278 KB)

    The parabolic equation (PE) method is a range dependent, wave theoretic model. Both the modeling and the numerical limitations of this method are investigated for a range independent ocean duct with parabolic index of refraction squared implemented using the split step Fourier algorithm. Equations are given for determining the minimum number of depth sampling points, and the error due to range ste... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Predicted Performance of a Heterodyne Detector with a Fiber Optic Coil Hydrophone

    Publication Year: 1981, Page(s):31 - 34
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (319 KB)

    In recent years, much attention has been focused on the application of fiber optics to underwater acoustic detection. In this regard, a hydrophone may be constructed of coiled optical fiber. Ultimately, it would be desirable to have only fiber optic elements and cables in the wet end of a towed array system. However, lead fibers are also susceptible to acoustic modulation, introducing grave ambigu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Tracking and Telemetry System for Severe Multipath Acoustic Channels

    Publication Year: 1981, Page(s):35 - 39
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB)

    Underwater telemetry systems require special design when they are to be used in severe multipath acoustic channels. This paper describes a modulation/signal processing method, called Spaced-Frequency-Shift Keying (SFSK), that effectively penetrates such channels. SFSK includes features for reliable message validation, message identification, transfer of binary telemetry, and operation over Doppler... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Multichannel Acoustic Telemetry System

    Publication Year: 1981, Page(s):40 - 42
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (269 KB)

    An acoustic system to measure a descent velocity of a self-contained instrument package is described in this paper. The system Is also capable of transmitting two additional time variables. The velocity measurement is based on the Doppler frequency shift of an acoustic signal, while the two other channels use frequency modulated carriers. Errors introduced by heave of a receiving hydrophone is com... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Versatile Multi-Channel Data Acquisition System for Seismic and Acoustic Applications

    Publication Year: 1981, Page(s):43 - 47
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (365 KB)

    Versatility and reliability were key factors in the the design of a minicomputer based digital data acquisition system. Used both at sea and on the polar ice with excellent results, it has been adapted to tasks ranging from at-sea continuous seismic profiling to low level acoustic transmission experiments. Of particular interest is a floating point amplifier utilizing a unique gain switching metho... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Survey of Acoustic Telemetry

    Publication Year: 1981, Page(s):48 - 54
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    Acoustic telemetry from underwater submersibles and sensors has been pursued ever since it was recognized that the ocean could support signal transmission. While it has been evident that some form of communication is possible, the ocean has proved to be a distressingly difficult medium in which to achieve high data rates. High data rate transmission requires a wide bandwidth which is severely cons... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • DATS - A Digital Acoustic Telemetry System for Underwater Communications

    Publication Year: 1981, Page(s):55 - 60
    Cited by:  Papers (7)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (543 KB)

    High data rate acoustic telemetry for underwater communications is limited by both the available bandwidth imposed by high frequency absorption and the range and Doppler spreading of the underwater channel. These limitations can be combatted by the use of spread channel communication techniques. Application of these techniques, however, has been limited by the space and power limitations required ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • MFSK--The Basis for Robust Acoustical Communications

    Publication Year: 1981, Page(s):61 - 66
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (411 KB)

    Subsea acoustic control and communications systems based on FSK modulation have been used in the offshore industry for the past few years. Prerequisites for reliable link operation included frequency and spatial diversity, signal coding, and channel equalization. These prerequisites limited previous systems to very low data rates. In this paper, an acoustic modem capable of an order of magnitude i... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Applications of the MFSK Acoustic Communications System

    Publication Year: 1981, Page(s):67 - 71
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (367 KB)

    Requirements for control and data acquisition from remote subsea wellheads are expected to grow during the 1980s. In this paper, the implementation of an 'underwater acoustic approach is developed, together with the companion problems-achieving hardware reliability and low power consumption. A companion paper, "MFSK-The Basis for Robust Acoustical Communications," outlines a technique for achievin... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Benthic 4800 BITS/S Acoustic Telemetry

    Publication Year: 1981, Page(s): 72
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (44 KB)

    In June, 1981, continuous 4800 bits/s digital data was acoustically telemetered in 15,000-foot deep water from a near-bottom instrumentation package to a surface platform. As the platform drifted from overhead to an offset angle greater than 45° from the vertical, over 1.0×107 bits of pseudo-random digital data were transmitted with a total of 10 received errors, yielding ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Identification of Missions for Potential Unmanned Untethered Submersible Systems

    Publication Year: 1981, Page(s):73 - 77
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (437 KB)

    This paper's objective Is to Identify near and far-term underwater/Ice missions for which potential unmanned, untethered submersible (UUS) systems may become prime candidates. Its introduction includes a review of subjects to be considered and the rationale for procedures followed. Overviews of possible UUS systems and their general potential for serving underwater/ice missions are presented. An a... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Torpedo Technology in the 1980's

    Publication Year: 1981, Page(s):78 - 82
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    New technology provides the opportunity for significant advances in undersea vehicles. Advances in artificial intelligence will permit vehicles to "learn" from measuring their environment and be able to distinguish desired targets from fish, rocks, boundaries, etc. Very high speed integrated circuitry (VHSIC) will package this capability compactly. Lithium type batteries and high speed motors with... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Computer Systems for Autonomous Vehicles

    Publication Year: 1981, Page(s):83 - 87
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (382 KB)

    The advent of the microprocessor has permitted a substantial amount of computing power to be placed in underwater automata for inspections, work, and other tasks under conditions where tethers are not desirable. Hardware costs are low and power consumption minimal. This paper examines the impact of the microprocessor computer on the autonomous vehicle. The trend toward distributed processing, and ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamics and Hydrodynamics of Ocean Vehicles

    Publication Year: 1981, Page(s):88 - 91
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (342 KB)

    A state-of-the-art review of the dynamics of ocean vehicles is presented. A review of the six-degree-of-freedom nonlinear equations of motion acquaints the reader with the number, type and importance of the terms for various maneuvers. Application of these equations about the linearized equilibrium condition, Uο= constant, which decouples the horizontal and vertical plane equatio... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SPURV II-An Unmanned, Free-Swimming Submersible Developed for Oceanographic Research

    Publication Year: 1981, Page(s):92 - 98
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (644 KB)

    SPURV II, a Self-Propelled Underwater Research Vehicle, is the latest in a series of such vehicles developed by the Applied Physics Laboratory of the University of Washington for use in its oceanographic research programs. Previous vehicles include several earlier versions of SPURV for deep ocean work (to 3000 meters) and UARS (Unmanned Arctic Research Submersible), a vehicle for under-ice re- sea... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Epaulard: - Deep Bottom Surveys Now with Acoustic Remote Controlled Vehicle - First Operational Experience

    Publication Year: 1981, Page(s):99 - 103
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (815 KB)

    Designed in 1976, built in 77-78, tested at sea in 79-80 and now in operation on nodule fields in the Pacific Ocean, EPAULARD is the first acoustic remote controlled free swimming vehicule for deep ocean bottom photographic and bathymetric surveys. This paper describes briefly the system and presents at sea operational results including great depths (-5 300 meters). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The UNH EAVE-East Vehicle

    Publication Year: 1981, Page(s):104 - 108
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (298 KB)

    EAVE (Experimental Autonomous Vehicle) is a system for the development of technology for untethered, unmanned underwater vehicles. The central focus of this program is the use of a microprocessor system dedicated to mission performance and to the control of distributed processors. The slave processors interface with the vehicle environment, and activate appropriate responses. This paper describes ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robot II, A Small Unmanned Untethered Underwater Vehicle

    Publication Year: 1981, Page(s):109 - 112
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (330 KB)

    A small unmanned, untethered submarine vehicle has been designed and is nearing completion. It has a speed of three knots for about four hours with a design depth of 300 feet. The main mission of the vehicle is as aplatform for side-scan sonar. The vehicle has a cylindrical pressure hull fabricated in aluminum with an external skin to provide a low-drag shape. The submarine operates autonomously u... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tradeoff Studies for the Unmanned Free Swimming Submersible (UFSS) Vehicle

    Publication Year: 1981, Page(s):113 - 117
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (330 KB)

    In the early stages of the design of the UFSS vehicle decisions had to be made between fundamentally different solutions to three basic problems: the energy source, the propulsion method, and the hull shape, which determined drag. Accordingly a series of tradeoff studies was undertaken which considered the various alternatives in the light of the desired performance levels of the vehicle and the c... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.