2026-09-18T22:53:30Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/168982022-01-13T07:54:29Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Charles C. Counselman, III.
Hall, Timothy Douglas, 1970-
Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
2005-05-19T15:12:26Z
2005-05-19T15:12:26Z
2002
2002
http://hdl.handle.net/1721.1/16898
52060690
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 293-294).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
(cont.) Previous attempts at signal-of-opportunity navigation using carrier phase sidestepped the ambiguity problem by requiring that the initial position of the rover be known and that phase variations be tracked without interruption. I designed and implemented an ambiguity-function method that enables the phase ambiguity to be resolved instantaneously without position initialization or signal-tracking continuity. I encountered several impediments to AM-broadcast-based radiolocation that, if not dealt with appropriately, reduce positioning accuracy, reduce ambiguity-resolution robustness, or both. AM transmitter position uncertainty directly causes receiver position-determination uncertainty. Since the error in published antenna positions sometimes exceeds 100 meters, I conducted sub-meter-accuracy geodetic surveys of 29 Boston-area AM-broadcast antennas. The directional radiation patterns of the array antennas of many AM broadcast radio stations have phases that vary with azimuth angle. I developed and implemented a model for the phase of a directional antenna that nearly eliminated theerrors caused by this effect. AM broadcast signals travel primarily as groundwaves, which propagate with phase velocities that depend on the electrical properties of the ground. Using simulations and empirical data, I designed and implemented a model for groundwave propagation that greatly reduced the errors caused by this effect over a broad geographic area ...
by Timothy Douglas Hall.
Ph.D.
294 p.
10673563 bytes
10673275 bytes
application/pdf
application/pdf
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
http://dspace.mit.edu/handle/1721.1/7582
Electrical Engineering and Computer Science.
Radiolocation using AM broadcast signals
Radiolocation using amplitude modulation broadcast signals
Thesis
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<Abstract>(cont.) Previous attempts at signal-of-opportunity navigation using carrier phase sidestepped the ambiguity problem by requiring that the initial position of the rover be known and that phase variations be tracked without interruption. I designed and implemented an ambiguity-function method that enables the phase ambiguity to be resolved instantaneously without position initialization or signal-tracking continuity. I encountered several impediments to AM-broadcast-based radiolocation that, if not dealt with appropriately, reduce positioning accuracy, reduce ambiguity-resolution robustness, or both. AM transmitter position uncertainty directly causes receiver position-determination uncertainty. Since the error in published antenna positions sometimes exceeds 100 meters, I conducted sub-meter-accuracy geodetic surveys of 29 Boston-area AM-broadcast antennas. The directional radiation patterns of the array antennas of many AM broadcast radio stations have phases that vary with azimuth angle. I developed and implemented a model for the phase of a directional antenna that nearly eliminated theerrors caused by this effect. AM broadcast signals travel primarily as groundwaves, which propagate with phase velocities that depend on the electrical properties of the ground. Using simulations and empirical data, I designed and implemented a model for groundwave propagation that greatly reduced the errors caused by this effect over a broad geographic area ...</Abstract>
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