Broadband Modal Coherence and Beamforming at Megameter Ranges PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Broadband Modal Coherence and Beamforming at Megameter Ranges PDF full book. Access full book title Broadband Modal Coherence and Beamforming at Megameter Ranges by Kathleen E. Wage. Download full books in PDF and EPUB format.
Author: Kathleen E. Wage Publisher: ISBN: Category : Fourier analysis Languages : en Pages : 650
Book Description
Normal modes, the eigenfunctions of the ocean waveguide, are useful in underwater acoustics because the lowest modes provide an efficient description of the most energetic signals at long ranges. Understanding the structure of the mode arrivals at megameter ranges is crucial to tomographic and matched field processing applications, but there have been few opportunities for experimental observation of these signals. First, this thesis develops a short-time Fourier transform (STFT) framework for estimating broadband signals propagating in the lowest modes. Since previous research has focused on narrowband sources, this work concentrates on broadband processing issues. Specifically, it addresses the fundamental issue of frequency resolution required for mode estimation, analyzes the performance characteristics of two modal beamforming algorithms and explores the time/frequency trade-offs inherent in STFT mode processing. Second, this work presents a detailed analysis of the low-mode arrivals at megameter ranges using data from the Acoustic Thermometry of Ocean Climate experiment. Short-time Fourier processing of receptions at a range of 3,515 kilometers reveal a complicated multipath arrival structure. This thesis characterizes the temporal coherence of the arrivals, computes average dispersion curves, and examines trends in arrival time over five months of data.
Author: Kathleen E. Wage Publisher: ISBN: Category : Fourier analysis Languages : en Pages : 650
Book Description
Normal modes, the eigenfunctions of the ocean waveguide, are useful in underwater acoustics because the lowest modes provide an efficient description of the most energetic signals at long ranges. Understanding the structure of the mode arrivals at megameter ranges is crucial to tomographic and matched field processing applications, but there have been few opportunities for experimental observation of these signals. First, this thesis develops a short-time Fourier transform (STFT) framework for estimating broadband signals propagating in the lowest modes. Since previous research has focused on narrowband sources, this work concentrates on broadband processing issues. Specifically, it addresses the fundamental issue of frequency resolution required for mode estimation, analyzes the performance characteristics of two modal beamforming algorithms and explores the time/frequency trade-offs inherent in STFT mode processing. Second, this work presents a detailed analysis of the low-mode arrivals at megameter ranges using data from the Acoustic Thermometry of Ocean Climate experiment. Short-time Fourier processing of receptions at a range of 3,515 kilometers reveal a complicated multipath arrival structure. This thesis characterizes the temporal coherence of the arrivals, computes average dispersion curves, and examines trends in arrival time over five months of data.
Author: P. Thushara D. Abhayapala Publisher: ISBN: Category : Antenna arrays Languages : en Pages : 167
Book Description
This thesis considers the design of a beamformer which can enhance desired signals in an environment consisting of broadband nearfield and/or farfield sources. The thesis contains: a formulation of a set of analysis tools which can provide insight into the intrinsic structure of array processing problems; a methodology for nearfield beamforming; theory and design of a general broadband beamformer; and a consideration of a coherent nearfield broadband adaptive beamforming problem. To a lesser extent, the source localization problem and background noise modeling are also treated. A set of analysis tools called modal analysis techniques which can be used to a solve wider class of array signal processing problems, is first formulated. The solution to the classical wave equation is studied in detail and exploited in order to develop these techniques. Three novel methods of designing a beamformer having a desired nearfield broadband beampattern are presented ...
Author: Thomas Rossing Publisher: Springer Science & Business Media ISBN: 0387304460 Category : Science Languages : en Pages : 1179
Book Description
This is an unparalleled modern handbook reflecting the richly interdisciplinary nature of acoustics edited by an acknowledged master in the field. The handbook reviews the most important areas of the subject, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest research and applications are incorporated throughout, including computer recognition and synthesis of speech, physiological acoustics, diagnostic imaging and therapeutic applications and acoustical oceanography. An accompanying CD-ROM contains audio and video files.
Author: Douglas A. Abraham Publisher: Springer ISBN: 3319929836 Category : Technology & Engineering Languages : en Pages : 834
Book Description
This book provides comprehensive coverage of the detection and processing of signals in underwater acoustics. Background material on active and passive sonar systems, underwater acoustics, and statistical signal processing makes the book a self-contained and valuable resource for graduate students, researchers, and active practitioners alike. Signal detection topics span a range of common signal types including signals of known form such as active sonar or communications signals; signals of unknown form, including passive sonar and narrowband signals; and transient signals such as marine mammal vocalizations. This text, along with its companion volume on beamforming, provides a thorough treatment of underwater acoustic signal processing that speaks to its author’s broad experience in the field.
Author: Eni Njoku Publisher: ISBN: 9781785396229 Category : Electronic books Languages : en Pages :
Book Description
This first encyclopaedic reference on remote sensing describes the concepts, techniques, instrumentation, data analysis, interpretation, and applications of remote sensing, both airborne and space-based. Scientists, engineers, academics, and students can quickly access answers to their reference questions and direction for further study.
Author: Kathleen E. Wage
Author: Kathleen E. Wage
Author: 
Author: P. Thushara D. Abhayapala
Author: 
Author: Woods Hole Oceanographic Institution
Author: Acoustical Society of America
Author: Thomas Rossing
Author: Douglas A. Abraham
Author: Eni Njoku
Author: Robert J. Urick