Persistent Link:
http://hdl.handle.net/10150/193724
Title:
A New High-Sensitivity Subsurface Sensing System
Author:
Krichenko, Oleg
Issue Date:
2007
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
We developed a prototype geophysical system that currently has a dynamic range of 126dB. We also calculate the full potential of our design to achieve a dynamic range of greater than 160dB, which is orders of magnitude higher than what is currently offered by state of the art technology in geophysical instrumentation. We have been successful in reducing measurement errors that are common limiting factors in achieving high measurement sensitivity in practice. We reduced the measurement error caused by mechanical deformations of the measurement apparatus from 70PPM to less than 1PPM. As a result of developing a novel measurement method for using a rotating antenna array and digital nulling, we achieved a level of temporal drift of less than 1PPM over a 50 minute time period, which is a significant improvement compared to the drift of greater than 100PPM for the state of the art geophysical instrumentation. We also used a method of simultaneous calibration of the secondary fields in order to correct the measured data for the long-term gain variations in the system response. As a result, we reduced the percentage error in the RE and IM components of the target response measured over a 105-minute period of time from 5% and 80% to 0.5% and 2%, respectively. We have gained a substantial reduction of the measurement errors caused by the background response of the earth by using the antenna array in a vertical orientation relative to the earth's surface. We demonstrated that our measurement method increases survey efficiency because of a more informative set of data. We tested our prototype system with a section of steel pipe, which is a standard target used to determine the sensitivity of commercial metal detectors. The measurement results showed that our current system will detect this particular target at a 2.0m depth below the earth's surface, which is 0.5m better than the 1.5m detection depth achieved by the EM61-MK2. When the full potential of our design is realized, we estimate the projected depth of detection to increase to 9m, which is six times greater than the detection depth achieved by the EM61-MK2.
Type:
text; Electronic Dissertation
Keywords:
electronics; engineering; geophysics; imaging; sensing; subsurface
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Electrical & Computer Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Dvorak, Steven L; Sternberg, Ben K
Committee Chair:
Dvorak, Steven L; Sternberg, Ben K

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleA New High-Sensitivity Subsurface Sensing Systemen_US
dc.creatorKrichenko, Olegen_US
dc.contributor.authorKrichenko, Olegen_US
dc.date.issued2007en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractWe developed a prototype geophysical system that currently has a dynamic range of 126dB. We also calculate the full potential of our design to achieve a dynamic range of greater than 160dB, which is orders of magnitude higher than what is currently offered by state of the art technology in geophysical instrumentation. We have been successful in reducing measurement errors that are common limiting factors in achieving high measurement sensitivity in practice. We reduced the measurement error caused by mechanical deformations of the measurement apparatus from 70PPM to less than 1PPM. As a result of developing a novel measurement method for using a rotating antenna array and digital nulling, we achieved a level of temporal drift of less than 1PPM over a 50 minute time period, which is a significant improvement compared to the drift of greater than 100PPM for the state of the art geophysical instrumentation. We also used a method of simultaneous calibration of the secondary fields in order to correct the measured data for the long-term gain variations in the system response. As a result, we reduced the percentage error in the RE and IM components of the target response measured over a 105-minute period of time from 5% and 80% to 0.5% and 2%, respectively. We have gained a substantial reduction of the measurement errors caused by the background response of the earth by using the antenna array in a vertical orientation relative to the earth's surface. We demonstrated that our measurement method increases survey efficiency because of a more informative set of data. We tested our prototype system with a section of steel pipe, which is a standard target used to determine the sensitivity of commercial metal detectors. The measurement results showed that our current system will detect this particular target at a 2.0m depth below the earth's surface, which is 0.5m better than the 1.5m detection depth achieved by the EM61-MK2. When the full potential of our design is realized, we estimate the projected depth of detection to increase to 9m, which is six times greater than the detection depth achieved by the EM61-MK2.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectelectronicsen_US
dc.subjectengineeringen_US
dc.subjectgeophysicsen_US
dc.subjectimagingen_US
dc.subjectsensingen_US
dc.subjectsubsurfaceen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineElectrical & Computer Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorDvorak, Steven Len_US
dc.contributor.advisorSternberg, Ben Ken_US
dc.contributor.chairDvorak, Steven Len_US
dc.contributor.chairSternberg, Ben Ken_US
dc.contributor.committeememberDvorak, Steven L.en_US
dc.contributor.committeememberSternberg, Ben K.en_US
dc.contributor.committeememberBarton, Jennifer K.en_US
dc.identifier.proquest2255en_US
dc.identifier.oclc659748094en_US
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