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IEEE Journal of Oceanic Engineering

Issue 3 • Jul 1993

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Displaying Results 1 - 21 of 21
  • Refined autoregressive moving average modeling of underwater heave process

    Publication Year: 1993, Page(s):351 - 355
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    Earlier treatments of the underwater dynamic motion effects including the heave, or vertical dynamic motion, phenomenon relied on frequency response methods and Kalman filtering for the compensation task. An alternative model of the heave process is proposed. The model is based on transforming the underlying time series using exponential operations and then finding autoregressive integrated moving... View full abstract»

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  • Mine avoidance techniques for underwater vehicles

    Publication Year: 1993, Page(s):340 - 350
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1132 KB)

    It is shown that by implementing certain mine avoidance techniques, an underwater vehicle equipped with an obstacle avoidance sonar (OAS) and a navigation system can safely navigate an unknown minefield. The mine avoidance techniques take into account the physical limitations of the sonar and the navigation system, the maneuverability constraints on the underwater vehicle, and the required safe st... View full abstract»

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  • An iterative method for array pattern synthesis

    Publication Year: 1993, Page(s):280 - 286
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (788 KB)

    The authors propose a novel iterative method for synthesizing radiation patterns of linear arrays with arbitrary sidelobe envelopes, with nonisotropic elements, and with nonuniform spacing between elements. Various design examples are presented and compared with other methods. It is shown that the proposed iterative method converges rapidly and yields superior results over other methods View full abstract»

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  • Multivariable sliding mode control for autonomous diving and steering of unmanned underwater vehicles

    Publication Year: 1993, Page(s):327 - 339
    Cited by:  Papers (421)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1176 KB)

    A six-degree-of-freedom model for the maneuvering of an underwater vehicle is used and a sliding-mode autopilot is designed for the combined steering, diving, and speed control functions. In flight control applications of this kind, difficulties arise because the system to be controlled is highly nonlinear and coupled, and there is a good deal of parameter uncertainty and variation with operationa... View full abstract»

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  • Interrelations between matched-field processing and airborne MTI radar

    Publication Year: 1993, Page(s):168 - 180
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1468 KB)

    In matched field processing (MFP) the spatial characteristics of a dispersive wave field are exploited to estimate certain parameters of the acoustic field, such as source location or characteristics of the acoustic channel including environmental parameters. In airborne MTI (AMTI) radar, interfering echoes (clutter) are Doppler colored due to the platform motion. Optimum clutter suppression requi... View full abstract»

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  • A novel array of elliptic ring radiators

    Publication Year: 1993, Page(s):271 - 279
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (860 KB)

    An array of elliptic ring radiators is proposed which generates a fan-type beam with controllable sidelobe levels. Such an array has applications in specialized acoustic systems such as sidescan sonars, sonars for fish finding and stock assessment, obstacle avoidance systems, and others. Two possible approaches to the design are presented. One approach utilizes a mapping which transforms a radiati... View full abstract»

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  • Towfish orientation and position estimation

    Publication Year: 1993, Page(s):319 - 326
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (844 KB)

    The towfish location and orientation problems that arise in using side-scan sonar to detect objects on the sea bottom are treated separately. Data which locate the towfish relative to the ship are usually deteriorated by multipath receptions and other effects. In order to overcome this serious degradation in the location measurements, a modified Kalman filter is proposed. An estimate of the state ... View full abstract»

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  • Estimation and detection issues in matched-field processing

    Publication Year: 1993, Page(s):156 - 167
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1508 KB)

    A conceptual framework in which the model-based, space-time acoustic signal processing procedure known as matched field processing (MFP) can be handled in a consistent manner is established. A framework for strong-signal MFP based on standard statistical estimation theory, in which MFP is regarded as essentially an estimation problem in the strong-signal regime, is developed. In the weak-signal ca... View full abstract»

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  • Estimation of ocean-bottom properties by matched-field inversion of acoustic field data

    Publication Year: 1993, Page(s):232 - 239
    Cited by:  Papers (75)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (940 KB)

    A method for estimating properties of the ocean bottom such as bathymetry and geoacoustic parameters such as sound speed, density and attenuation, using matched-field inversion is considered. The inversion can be formulated as an optimization problem by assuming a discrete model of unknown parameters and a bounded search space for each parameter. The optimization then involves finding the set of p... View full abstract»

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  • A nearest neighbor algorithm for fast matched-field processing with a vertical line array

    Publication Year: 1993, Page(s):265 - 270
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    Selection of replica fields that are most like the data, i.e., the nearest neighbors (NNs) to the data, offers a way of reducing the computational search space in matched-field processing, thereby making larger physical search spaces or a larger number of frequencies practical. To enable selection of NNs a vector basis for the search space is required. The authors use the large eigenvectors of the... View full abstract»

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  • Issues in the implementation of an indirect adaptive control system

    Publication Year: 1993, Page(s):311 - 318
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (968 KB)

    This work presents techniques for addressing the various issues relevant to the implementation of an indirect adaptive control system. The sufficiency of these techniques is demonstrated by implementation onboard a small autonomous underwater vehicle. The control system is organized into two layers: the standard adaptive control algorithms and the supervisory logic. Modeling and implementation iss... View full abstract»

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  • Matched field inversion for geoacoustic model parameters using adaptive simulated annealing

    Publication Year: 1993, Page(s):224 - 231
    Cited by:  Papers (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1036 KB)

    A method is described for the estimation of geoacoustic model parameters by the inversion of acoustic field data using a nonlinear optimization procedure based on simulated annealing. The cost function used by the algorithm is the Bartlett matched-field processor (MFP), which related the measured acoustic field with replica fields calculated by the SAFARI fast field program. Model parameters are p... View full abstract»

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  • Robust broadband matched-field processing: performance in shallow water

    Publication Year: 1993, Page(s):253 - 264
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1204 KB)

    An issue of concern for matched-field processing is the strong dependence between performance and precise knowledge about the environmental parameters. A robust matched-field processor based on minimax robust filtering methods was developed. Here, simulation methods are employed to evaluate the performance of the minimax robust method as well as other robust methods for a range-independent shallow... View full abstract»

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  • Measurement of ocean wave spectra using a ship-mounted HF radar

    Publication Year: 1993, Page(s):306 - 310
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (532 KB)

    The work describes an inversion algorithm for HF radar measurement of nondirectional wave spectra using an omnidirectional receive/transmit antenna. Such a radar would be suitable for deployment on a stationary ship or drill rig. In this approach, wave information is extracted from the radar observations by numerically inverting the integral equation representing the backscatter return from the oc... View full abstract»

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  • VLF source localization with a freely drifting acoustic sensor array

    Publication Year: 1993, Page(s):209 - 223
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1792 KB)

    The source localization and tracking capability of the freely drifting Swallow float volumetric array is demonstrated with the matched-field processing (MFP) technique using the 14-Hz CW data collected during a 1989 float experiment conducted in the northeast Pacific. Initial MFP of the experimental data revealed difficulties in estimating the source depth and range while the source azimuth estima... View full abstract»

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  • Chaotic radar signal processing over the sea

    Publication Year: 1993, Page(s):287 - 295
    Cited by:  Papers (71)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (964 KB)

    It is demonstrated that the random nature of sea clutter may be explained as a chaotic phenomenon. For different sets of real sea clutter data, a correlation dimension analysis is used to show that sea clutter can be embedded in a finite-dimensional space. The result of correlation dimension analysis is used to construct a neural network predictor for reconstructing the dynamics of sea clutter. Th... View full abstract»

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  • Ocean acoustic field matching: normal mode filtering and non-Gaussian sources

    Publication Year: 1993, Page(s):181 - 188
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1016 KB)

    Two qualitative results concerning statistical sonar signal processing and acoustic field matching are obtained. First, normal-mode field predictions are integrated with statistical signature analysis by constructing a boundary-value problem in the acoustic waveguide. From this construction it is found that the normal-mode filter is the unique acoustic preprocessor which does not confound determin... View full abstract»

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  • Sound velocity profile estimation: a system theoretic approach

    Publication Year: 1993, Page(s):240 - 252
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1340 KB)

    A system-theoretic approach is proposed to investigate the feasibility of reconstructing a sound velocity profile (SVP) from acoustical hydrophone measurements. A state-space representation of the normal-mode propagation model is used. It is shown that this representation can be utilized to investigate the so-called observability of the SVP from noisy measurement data. A model-based processor is d... View full abstract»

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  • Measurement of ocean wave spectra using narrow-beam HE radar

    Publication Year: 1993, Page(s):296 - 305
    Cited by:  Papers (60)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1120 KB)

    A data interpretation algorithm is developed to extract ocean wave information from HF radar backscatter observed by a narrow-beam antenna system. The basis of this measurement is the inversion of the integral equation representing the second-order radar cross section of the ocean surface. This equation is numerically inverted by approximating it as a matrix equation and pseudoinverting the kernel... View full abstract»

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  • Performance bounds for passively locating a moving source of a known frequency in oceanic waveguide using a vertical array

    Publication Year: 1993, Page(s):189 - 198
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1056 KB)

    This work obtains analytical expressions for the Cramer-Rao lower bounds on the accuracy of location and velocity estimates obtainable by observing the signal radiated from a moving acoustic source at a vertical array of stationary sensors in oceanic waveguide using normal mode description of the sound field. The source radiates a continuous wave of a known frequency, and the source motion is assu... View full abstract»

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  • A posteriori probability source localization with uncertain mesoscale eddy currents

    Publication Year: 1993, Page(s):199 - 208
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1112 KB)

    Long-range source localization is shown to be affected by a mesoscale eddy whose realization is solely a cyclonic current (no thermal manifestation). The sensitivity of a matched-field type processor (known ocean) to an eddy is demonstrated, as well as its sensitivity to a mismatch between the parameters of the eddy and the processor assumptions. Optimum uncertain field processing techniques are u... View full abstract»

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Aims & Scope

The IEEE Journal of Oceanic Engineering (ISSN 0364-9059) is the online-only quarterly publication of the IEEE Oceanic Engineering Society (IEEE OES). The scope of the Journal is the field of interest of the IEEE OES, which encompasses all aspects of science, engineering, and technology that address research, development, and operations pertaining to all bodies of water. This includes the creation of new capabilities and technologies from concept design through prototypes, testing, and operational systems to sense, explore, understand, develop, use, and responsibly manage natural resources.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
N. Ross Chapman
School of Earth & Ocean Sciences
University of Victoria
3800 Finnerty Road
Victoria, BC V8P 5C2 Canada
chapman@uvic.ca