Experimental investigation of a high resolution sonar
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Authors
Huat, Lim Chin
Subjects
Synthetic aperture sonar
Pulse compression
Glint
Speckle
Signal-to-noise ratio
Pulse compression
Glint
Speckle
Signal-to-noise ratio
Advisors
Walters, Donald L.
Atchley, Anthony A.
Date of Issue
1996-03
Date
March 1996
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
This thesis investigated a laboratory synthetic aperture sonar designed to test the algorithms and techniques needed to detect, classify and identify minelike objects. Previous synthetic aperture sonar work at NPS achieved 5 cm range resolution and 1 cm azimuth resolution. This thesis developed a pulsed, frequency modulated, synthetic aperture sonar that achieved range and azimuth resolutions of about 1 cm. The processed images clearly reveal targets with a high degree of certainty. However, the ability to classify and identify mines and rocks is less certain because of speckle and glint effects. The high resolution algorithms improved the detection and overall image quality of targets, and achieved a signal to noise ratio of 35 dB. The 2:1 frequency spread of the FM chirp increased the signal to noise ratio by 20 dB compared to an unfocused synthetic aperture system. However, a significant finding is that resolution alone is not sufficient to classify and identify minelike targets in complex backgrounds. Resolution of this problem will require a different approach such as utilizing adaptive acoustic daylight to avoid the speckle and glint problems inherent with coherent illumination. To achieve a classification and identification capability, a completely different approach to acoustic illumination and signal processing is needed.
Type
Thesis
Description
Series/Report No
Department
Department of Physics
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
79 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
Copyright is reserved by the copyright owner