ECE Seminar* Speaker: Dr. T. C Yang, Professor, Zhejiang University, China
When: Friday,
June 30, 2017
2:00 PM
-
3:00 PM
Where: Science & Engineering Building, Lester W. Cory Conference Room: Room 213A
Cost: Free
Description: Topic: Improved Direction of Arrival (DOA) Estimation by Deconvolving the Conventional Beamforming
Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A
Abstract:
Hydrophone arrays are used in underwater environments to detect/separate a weak signal and estimate its direction of arrival from many loud interfering sources and ambient noise. Conventional beamforming is robust but suffers from fat beams and high level sidelobes. High resolution beamforming, such as minimum-variance distortionless-response (MVDR) based on the inverse of the signal covariance matrix, yields narrow beam widths and low sidelobe levels but is sensitive to signal mismatch and requires many snapshots of data. Recognizing that the wide beam widths and high sidelobe levels in conventional beam outputs are arti-facts of conventional beamforming, one should be able to recover the original signal distribution by deconvolving the conventional beamforming output. Deconvolution can be an ill-posed problem. This paper applies deconvolution algorithm used in image de-blurring to the conventional beam power to avoid the instability problems of common deconvolution methods. The deconvolved beam power yields narrow beams, and low sidelobe levels similar to, or better than high resolution beamforming, and at the same time retains the robustness of conventional beamforming. It yields a higher output signal-to-noise ratio than conventional (and MVDR) beamforming for isotropic noise (higher directivitiy index). This talk gives examples for a horizontal line array and a circular array, and discusses implications/applications for practical sonar systems. Performance is evaluated with simulated and real data.
Biography:
T. C. Yang received the Ph.D. degree in high energy physics from the University of Rochester, Rochester, NY, USA, in 1971. He is currently a Professor and previously a Pao Yu-Kong Chair Professor at the Zhejiang University. From 2012 to 2014, he was a National Science Counsel Chair Professor at the Nat. Sun Yat-Sen Univ. Kaohsiung, Taiwan. Before that, he spent 32 years working at the Naval Research Laboratory, Washington, DC, serving as Head of the Arctic Section, Dispersive Wave Guide Effects Group, and acting Head of the Acoustic Signal Processing Branch, and consultant to the division on research proposals. His current research focuses on: (1) environmental impacts on underwater acoustic communications and networking, exploiting the channel physics to characterize and improve performance, (2) environmental acoustic sensing and signal processing using distributed networked sensors, and (3) methods for improved channel tracking and data-based source localization. In earlier years, he pioneered matched mode processing for a vertical line array, and matched-beam processing for a horizontal line array. Other areas of research included geoacoustic inversions, waveguide invariants, effects of internal waves on sound propagation in shallow water, Arctic acoustics, etc. He is a fellow of the Acoustical Society of America.
The Seminars is open to the public free of charge.
*For further information, please contact Dr. Paul J. Gendron at 508.999.8510, or by via email at pgendron@umassd.edu.
Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A
Abstract:
Hydrophone arrays are used in underwater environments to detect/separate a weak signal and estimate its direction of arrival from many loud interfering sources and ambient noise. Conventional beamforming is robust but suffers from fat beams and high level sidelobes. High resolution beamforming, such as minimum-variance distortionless-response (MVDR) based on the inverse of the signal covariance matrix, yields narrow beam widths and low sidelobe levels but is sensitive to signal mismatch and requires many snapshots of data. Recognizing that the wide beam widths and high sidelobe levels in conventional beam outputs are arti-facts of conventional beamforming, one should be able to recover the original signal distribution by deconvolving the conventional beamforming output. Deconvolution can be an ill-posed problem. This paper applies deconvolution algorithm used in image de-blurring to the conventional beam power to avoid the instability problems of common deconvolution methods. The deconvolved beam power yields narrow beams, and low sidelobe levels similar to, or better than high resolution beamforming, and at the same time retains the robustness of conventional beamforming. It yields a higher output signal-to-noise ratio than conventional (and MVDR) beamforming for isotropic noise (higher directivitiy index). This talk gives examples for a horizontal line array and a circular array, and discusses implications/applications for practical sonar systems. Performance is evaluated with simulated and real data.
Biography:
T. C. Yang received the Ph.D. degree in high energy physics from the University of Rochester, Rochester, NY, USA, in 1971. He is currently a Professor and previously a Pao Yu-Kong Chair Professor at the Zhejiang University. From 2012 to 2014, he was a National Science Counsel Chair Professor at the Nat. Sun Yat-Sen Univ. Kaohsiung, Taiwan. Before that, he spent 32 years working at the Naval Research Laboratory, Washington, DC, serving as Head of the Arctic Section, Dispersive Wave Guide Effects Group, and acting Head of the Acoustic Signal Processing Branch, and consultant to the division on research proposals. His current research focuses on: (1) environmental impacts on underwater acoustic communications and networking, exploiting the channel physics to characterize and improve performance, (2) environmental acoustic sensing and signal processing using distributed networked sensors, and (3) methods for improved channel tracking and data-based source localization. In earlier years, he pioneered matched mode processing for a vertical line array, and matched-beam processing for a horizontal line array. Other areas of research included geoacoustic inversions, waveguide invariants, effects of internal waves on sound propagation in shallow water, Arctic acoustics, etc. He is a fellow of the Acoustical Society of America.
The Seminars is open to the public free of charge.
*For further information, please contact Dr. Paul J. Gendron at 508.999.8510, or by via email at pgendron@umassd.edu.
Contact:
ECE: Electrical & Computer Engineering Department 508.999.9164 http://www.umassd.edu/engineering/ece/
Topical Areas: General Public, University Community, College of Engineering, Electrical and Computer Engineering