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Engineering in the Ocean Environment, Ocean '74 - IEEE International Conference on

Date 21-23 Aug. 1974

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Displaying Results 1 - 25 of 131
  • Foreword

    Publication Year: 1974, Page(s): 0
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    Freely Available from IEEE
  • [Front cover and table of contents]

    Publication Year: 1974, Page(s): 0
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1974, Page(s): 0
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    Freely Available from IEEE
  • Frequency scanning non linear sonar performance modelling

    Publication Year: 1974, Page(s):3 - 9
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Non-linear sonar allows high resolution sidelobe-free bathymetric surveillance over an exceptionally large frequency bandwidth. When one fixed and one frequency-scanned channel are transmitted simultaneously, mixing in the water produces a low, scanned, difference frequency signal. In a system being developed, the technique produces an ocean floor reflection signature with more than a decade bandw... View full abstract»

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  • Optimal design of acoustic sonar transducer arrays

    Publication Year: 1974, Page(s):3 - 9
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (771 KB)

    Acoustic and electromagnetic target seeking systems are generally designed to maximize signal-to-noise ratio in a given environment. In addition, they are sometimes required to discriminate among a multiplicity of simultaneously present targets. To fulfill these objectives, they generally have conflicting requirements placed upon their directional characteristics. A planar transducer array is used... View full abstract»

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  • Bo'sun, a high resolution automatic charting system for the continental shelf

    Publication Year: 1974, Page(s):10 - 14
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (557 KB)

    BO'SUN comprises hardware and software for generating, recording, and processing high resolution sonar data to produce contoured depth charts in depths to 2,000 feet. The hardware includes a multibeam acoustic depth sounder, CRT display, digital printer, and digital magnetic tape recorder which logs both sonar and navigation data. The software permits shore processing of the magnetic tape on a con... View full abstract»

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  • Low-frequency resonant-true projector for underwater sound

    Publication Year: 1974, Page(s):10 - 15
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    In the present work, the free-flooding resonant tube with a cylindrical ceramic driver is investigated as a class of low-frequency, light-weight projectors in which the volume velocity is enhanced by a high-Q resonance condition. View full abstract»

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  • The ACODAC ambient noise system

    Publication Year: 1974, Page(s):15 - 21
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (703 KB)

    The ACOustic DAta Capsule (ACODAC) system was designed to obtain long term, unattended measurements of the ambient acoustic noise in the deep ocean. The instrument consists of a 40" diameter pressure vessel containing a 7-channel low speed analog tape recorder, a time code generator, automatic gain ranging data amplifiers and an acoustic telemetry system. An associated vertical array of six hydrop... View full abstract»

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  • Binary telemetry in a high doppler underwater acoustic channel

    Publication Year: 1974, Page(s):16 - 20
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB)

    Communication of data to or from a moving underwater vehicle presents unique problems due to the low ratio of acoustic propagation velocity to potential vehicle speeds. Several binary telemetry methods are examined for performance in a noisy channel at Doppler values up to ±3 percent. Carrier frequencies of above 10 kHz are assumed and channel interference is Gaussian noise and multipath fa... View full abstract»

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  • Variable-Focus arrays for a height insensitive side-scan sonar

    Publication Year: 1974, Page(s):21 - 26
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (358 KB)

    A simple focused electronic beamforming approach is being developed for a side-scan bottom mapping sonar which will not have to be maintained at a constant height above the bottom is described. The signals from the elements of a flat receiving array are phase and amplitude corrected and summed in various combinations to form two parallel fan-beams with relatively constant arc resolution. They are ... View full abstract»

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  • A non-scanning sonar indicating in three dimensions

    Publication Year: 1974, Page(s):22 - 28
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (415 KB)

    Most sonar systems determine the bearing of an incoming signal either by scanning a beam through space or by examining the outputs of several preformed beams. Signal bearing may also be determined by operating on the set of relative signal amplitudes derived from four or more hydrophone arrays. So long as the set of relative responses is uniquely related to signal bearing, direction may be determi... View full abstract»

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  • Scattering from a sinusoidal ocean surface excited by an underwater acoustic line source

    Publication Year: 1974, Page(s):29 - 33
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The scattering of underwater acoustic waves from a rough ocean surface has been of interest for many years. Most theoretical approaches to the problem use the Helmholtz integral formulation, which requires many approximations to reach simple formulas. In most other approaches to the problem, the acoustic source is considered to have a small beam angle, or plane wave front, which neglects any direc... View full abstract»

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  • Buoyant cable arrays for spatial measurements in the deep ocean

    Publication Year: 1974, Page(s):31 - 35
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (361 KB)

    Moored horizontal cable spans have been supported at mid-water depths by subsurface buoys and floats (Ocean Telescope, Atlantic Test Bed). These large arrays require a ship fitted with specialized cable handling equipment and must be deployed slowly due to the large number of floats that must be attached to the cables. For some applications, the high cable tensions required to resist deflections a... View full abstract»

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  • Acoustic backscattering from uniform Arctic Sea ice

    Publication Year: 1974, Page(s):34 - 38
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (503 KB)

    The purpose of this study was to determine the acoustic backscattering produced from the bottom of flat, first-year sea ice. Most under-ice reverberation measurements have been made at low frequencies, using explosive sources. Our measurements were made with 60- kHz pulses, and should be of special importance to the higher frequency sonar systems. The experiment site was a first-year ice floe with... View full abstract»

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  • Response of a single point moored buoy to waves and breakers - A computer program

    Publication Year: 1974, Page(s):36 - 43
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (597 KB)

    The single-point mooring of a buoy provides an unmanned instrument station for many purposes. The motion and survival of such a system under normal and severe environmental conditions are of great importance in its design. The paper describes a mathematical model devised to simulate on a digital computer the dynamic response of single point moorings of surface and submerged buoys. The essential fe... View full abstract»

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  • Diffuse scattering from rough surfaces

    Publication Year: 1974, Page(s):39 - 43
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (221 KB)

    The problem of diffuse scattering from ocean surfaces defined by a normal stochastic process is under taken. It is assumed that the surface height profile is the sample mean of the number of profiles obtained for the random rough surface. Theoretical expressions for the returned power are developed by using the Helmholtz integral approach with Kirchhoff's approximations for the plane wave case. Th... View full abstract»

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  • Analysis of a multiple buoy instrument platform; A non linear model

    Publication Year: 1974, Page(s):44 - 48
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (435 KB)

    The dynamics of a taut-line mooring suspended by two series (in-line) buoys is studied. Both monochromatic and pseudo-random surface wave models are used as forcing functions. Nonlinearities in hydrodynamic drag and cable elasticity are treated and motions are restricted to two dimensions in a vertical plane. Numerical solutions, based on a previous work for single buoys, were performed on a digit... View full abstract»

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  • A multi-channel digital data acquisition systems

    Publication Year: 1974, Page(s):47 - 50
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (299 KB)

    The design of a multi channel digital data acquisition system for use with oceanographic acoustic sensor packages has been presented. The system uses FIR digital filters to efficiently band limit the signals to the bandwidth of interest. View full abstract»

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  • The deployment of an oceanographic deep sea Tri-Mooring

    Publication Year: 1974, Page(s): 49
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    A three-legged deep-sea mooring was successfully deployed and recovered by the Woods Hole Oceanographic Institution in the fall of 1973. The Tri-mooring supported a rigid three-dimensional array of current and temperature sensors for measuring internal waves in the main thermocline (600-1000 meters depth). The mooring was deployed in 5455 meters of water 700 kilometers southwest of Bermuda for a p... View full abstract»

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  • A low power ocean data recorder

    Publication Year: 1974, Page(s):51 - 52
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    An instrument has been designed to record vertical current information. It does this by sequentially monitoring pressure, temperature, and rotation sensors. The data is stored on a digital cassette tape recorder. In addition, it generates a signal for acoustically telemetering part of the data. This permits a check on performance without the need for recovery. The instruments can be readily adapte... View full abstract»

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  • Telemetry receiver and acoustic command system

    Publication Year: 1974, Page(s):53 - 56
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    A shipboard Telemetry Receiver Acoustic Command System (TRACS) was designed to be used for two way acoustic communication with and relocation of underwater instruments. The design objectives were compact size, low cost, multi-purpose capabilities, and ease of operation and maintenance of the system. The telemetry receiver system utilizes a four-hydrophone array, bandpass filters and amplifiers, pr... View full abstract»

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  • Barometric pressure measurements from buoys during AIDJEX 1972

    Publication Year: 1974, Page(s):53 - 60
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (680 KB)

    Electrical readout aneroid pressure sensors were used on two types of buoys which were deployed in an array around the main camp during AIDJEX 1972 to obtain barometric pressure measurements. Laboratory tests prior to the field experiment showed that the calibration of the sensors shifted when they were exposed to normal handling and room temperatures. Corrections for these shifts were obtained by... View full abstract»

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  • Telemetry of tidal data

    Publication Year: 1974, Page(s):57 - 61
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (431 KB)

    A system is described which acoustically telemeters data from a bottom-mounted recording tide gauge to a moored surface buoy and from there makes the data available via a VHF radio-telemetry link to a survey ship within a 25 to 35 km radius. The system can be easily deployed from the survey ship and enables tidal data to be obtained during the course of a survey, particularly in areas where the in... View full abstract»

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  • Continuous monitoring systems in long island sound: Description and evaluation

    Publication Year: 1974, Page(s):61 - 69
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    During the past year an instrumentation array consisting of a savonius rotor current meter, water temperature and salinity sensor and a specially designed transmissometer has been in operation on a converted NOMAD buoy deployed in eastern Long Island Sound. This array in combination with meteorological sensors including wind speed and direction, air temperature and barometric pressure is designed ... View full abstract»

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  • High reliability H.F. communications to span the oceans

    Publication Year: 1974, Page(s):62 - 66
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (409 KB)

    Long distance communications over the oceans can only be accomplished with H.F. radio or Satellites. Satellite system costs are extremely high and no significant cost reductions are being projected over the next 10-20 years. H.F. Communications systems however can be very economical but usually exhibit poor reliability and often less than desirable quality. This paper describes an automatic H.F. r... View full abstract»

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