Radius of curvature and location estimation of cylindrical objects with sonar using a multi-sensor configuration

buir.advisorBarshan, Billur
dc.contributor.authorSekmen, Ali Şafak
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.descriptionAnkara : Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 1997.en_US
dc.descriptionThesis (Master's) -- Bilkent University, 1997.en_US
dc.descriptionIncludes bibliographical references leaves 130-133.en_US
dc.description.abstractDespite their limitations, sonar sensors are very popular in time-of-flight measuring systems since they are inexpensive and convenient. One of the most important limitations of sonar is its low angular resolution. An adjustable multi-sonar configuration consisting of three transmitter/receiver ultrasonic transducers is used to improve the resolution. The radius of curvature estimation of cylindrical objects is accomplished with this configuration. Two different ways of rotating the transducers are considered. First, the sensors are rotated around their joints. Second, the sensors are rotated around their centers. Also, two methods of tirne-of-flight estimation are implemented which are thresholding and curve-fitting. Sensitivity analysis of the radius of curvature with respect to some important parameters is made. The bias-variance combinations of both estimators are compared to the Cramer-Rao lower bound. Theory and simulations are verified by experimental data from real sonar systems. Data is smoothed by extended Kalman filtering. Rotating around the center works better than rotating around the joint. Curve-fitting method is shown to be better than thresholding method both in the absence and presence of noise. The best results are obtained w'hen the sensors are rotated around their centers and the curve-fitting method is used to estimate the time- of-flight. There is about 30% improvement in the absence of noise and 50% improvement in the presence of noise.en_US
dc.description.statementofresponsibilitySekmen, Ali Şafaken_US
dc.format.extentxvii, 133 leavesen_US
dc.publisherBilkent Universityen_US
dc.subject.lccTK6580 .S45 1997en_US
dc.subject.lcshRadar--Mathematical models.en_US
dc.subject.lcshSonar--Mathematical models.en_US
dc.titleRadius of curvature and location estimation of cylindrical objects with sonar using a multi-sensor configurationen_US
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