Date of Award

Fall 1984

Document Type

Thesis

Department

Electrical & Computer Engineering

Program/Concentration

Electrical Engineering

Committee Director

John W. Stoughton

Committee Member

Steohen A. Zahorian

Committee Member

Joseph L. Hibey

Committee Member

Allan J. Zuckerwar

Call Number for Print

Special Collections; LD4331.E55K42

Abstract

A proposed solution to an aviation safety problem is based on passive detection of turbulent weather phenomena through their infrasonic emission. This thesis describes a system design that is adequate for detection and bearing evaluation of infrasounds. An array of four sensors, with the appropriate hardware, is used for the detection part. Bearing evaluation is based on estimates of time delays between sensor outputs. The generalized cross correlation (GCC), as the conventional time-delay estimation (TOE) method, is first reviewed. An adaptive TUt approach, using the least mean square (LMS) algorithm, is then discussed. A comparison between the two techniques is made and the advantages of the adaptive approach are listed. The behavior of the GCC, as a Roth processor, is examined for the anticipated signals. It is shown that the Roth processor has the desired effect of sharpening the peak of the correlation function. It is also shown that the LMSTDE technique is an equivalent implementation of the Roth processor in the time domain. A LMSTDE lead-lag model, with a variable stability coefficient and a convergence criterion, is designed. This model is employed in an automatic scheme developed for the sensor array. The software and hardware system parameters are derived and determined. The effectiveness of the system is illustrated through simulation and field testing.

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