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Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array./
Author:	Kintz, Andrew L.
Description:	1 online resource (303 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-07(E), Section: B.
Contained By:	Dissertation Abstracts International78-07B(E).
Subject:	Electrical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9781369591583

Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array.
Kintz, Andrew L.

Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array. - 1 online resource (303 pages)

Source: Dissertation Abstracts International, Volume: 78-07(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

This work advances state-of-the-art Radio Frequency (RF) emitter geolocation from an airborne or spaceborne antenna array. With an antenna array, geolocation is based on Direction of Arrival (DOA) estimation algorithms such as MUSIC. The MUSIC algorithm applies to arbitrary arrays of polarization sensitive antennas and yields high resolution. However, MUSIC fails to obtain its theoretical resolution for simultaneous, closely spaced, co-frequency signals. We propose the novel Nullspace MUSIC algorithm, which outperforms MUSIC and its existing modifications while maintaining MUSIC(apostrophe)s fundamental orthogonality test. Nullspace MUSIC applies a divide-and-conquer approach and estimates a single DOA at a time.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369591583Subjects--Topical Terms:

596380
Electrical engineering.
Index Terms--Genre/Form:

554714
Electronic books.

Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array.
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245 1 0 $a Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array.
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500 $a Source: Dissertation Abstracts International, Volume: 78-07(E), Section: B.
500 $a Adviser: Inder Gupta.
502 $a Thesis (Ph.D.) $c The Ohio State University $d 2016.
504 $a Includes bibliographical references
520 $a This work advances state-of-the-art Radio Frequency (RF) emitter geolocation from an airborne or spaceborne antenna array. With an antenna array, geolocation is based on Direction of Arrival (DOA) estimation algorithms such as MUSIC. The MUSIC algorithm applies to arbitrary arrays of polarization sensitive antennas and yields high resolution. However, MUSIC fails to obtain its theoretical resolution for simultaneous, closely spaced, co-frequency signals. We propose the novel Nullspace MUSIC algorithm, which outperforms MUSIC and its existing modifications while maintaining MUSIC(apostrophe)s fundamental orthogonality test. Nullspace MUSIC applies a divide-and-conquer approach and estimates a single DOA at a time.
520 $a Additionally, an antenna array on an aircraft cannot be perfectly calibrated. RF waves are blocked, reflected, and scattered in a time-varying fashion by the platform around the antenna array. Consequently, full-wave electromagnetics simulations or demanding measurements of the entire platform cannot eliminate the mismatch between the true, in-situ antenna patterns and the antenna patterns that are available for DOA estimation (the antenna array manifold). Platform-induced manifold mismatch severely degrades MUSIC(apostrophe)s resolution and accuracy. We show that Nullspace MUSIC improves DOA accuracy for well separated signals that are incident on an airborne antenna array. Conventionally, geolocation from a mobile platform draws Lines of Bearing (LOB) from the antenna array along the DOAs to find the locations where the DOAs intersect with the ground. However, averaging the LOBs in the global coordinate system yields large errors due to geometric dilution of precision. Since averaging positions fails, a single emitter is typically located by finding the position on the ground that yields the Minimum Apparent Angular Error (MAAE) for the DOA estimates over a flight. We extend the MAAE approach to cluster LOBs from multiple emitters. MAAE clustering geolocates multiple simultaneous and co-frequency emitters in spite of highly erratic DOA estimates. We also mitigate manifold mismatch by applying the Direct Mapping Method (DMM). DMM averages DOA spectra on the earth(apostrophe)s surface and estimates the emitter locations directly from the composite spectrum. In the example results presented, our goal is to geolocate four diversely polarized emitters with a seven-element antenna array. This is too challenging for MAAE and DMM. We fuse Nullspace MUSIC and DMM into the novel Nullspace DMM algorithm and demonstrate that Nullspace DMM locates all emitters.
520 $a Finally, we apply the proposed geolocation algorithms to real-world experimental data. A six-element antenna array and Data Collection System (DCS) were installed on a small aircraft. The DCS recorded signals from four live transmitters during a three-hour flight over Columbus, Ohio. The four emitters were geolocated from various segments of the flight. As expected, individual DOA estimates were erratic and widespread due to the airplane(apostrophe)s perturbations of the measured array manifold. MAAE and DMM locate at most three of the four emitters. On the other hand, Nullspace DMM yields unambiguous estimates for every emitter in every flight segment. The successful experimental trials show that Nullspace DMM could significantly enhance airborne emitter geolocation in missions such as RF spectrum enforcement, locating unknown transmitters for defense, and search and rescue operations.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Electrical engineering. $3 596380
650 4 $a Mathematics. $3 527692
650 4 $a Systems science. $3 1148479
650 4 $a Aerospace engineering. $3 686400
650 4 $a Applied mathematics. $3 1069907
650 4 $a Optics. $3 595336
650 4 $a Engineering. $3 561152
650 4 $a Physics. $3 564049
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710 2 $a The Ohio State University. $b Electrical and Computer Engineering. $3 845530
773 0 $t Dissertation Abstracts International $g 78-07B(E).
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