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Microwave-Spectral Signatures Would Reveal Concealed ObjectsA proposed technique for locating concealed objects (especially small antipersonnel land mines) involves the acquisition and processing of spectral signatures over broad microwave frequency bands. This technique was conceived to overcome the weaknesses of older narrow- band electromagnetic techniques like ground-probing radar and low-frequency electromagnetic induction. Ground-probing radar is susceptible to false detections and/or interference caused by rocks, roots, air pockets, soil inhomogeneities, ice, liquid water, and miscellaneous buried objects other than those sought. Moreover, if the radar frequency happens to be one for which the permittivity of a sought object matches the permittivity of the surrounding soil or there is an unfavorable complex-amplitude addition of the radar reflection at the receiver, then the object is not detected. Low-frequency electromagnetic induction works well for detecting metallic objects, but the amounts of metal in plastic mines are often too small to be detectable. The potential advantage of the proposed technique arises from the fact that wideband spectral signatures generally contain more relevant information than do narrow-band signals. Consequently, spectral signatures could be used to make better decisions regarding whether concealed objects are present and whether they are the ones sought. In some cases, spectral signatures could provide information on the depths, sizes, shapes, and compositions of objects. An apparatus to implement the proposed technique (see Figure 1) could be assembled from equipment already in common use. Typically, such an apparatus would include a radio-frequency (RF) transmitter/receiver, a broad-band microwave antenna, and a fast personal computer loaded with appropriate software. In operation, the counter would be turned on, the antenna would be aimed at the ground or other mass suspected to contain a mine or other sought object, and the operating frequency would be swept over the band of interest.
Document ID
20110020546
Acquisition Source
Johnson Space Center
Document Type
Other - NASA Tech Brief
External Source(s)
http://www.techbriefs.com/component/content/845?task=view
Authors
Arndt, G. (NASA Johnson Space Center Houston, TX, United States)
Ngo, P. (NASA Johnson Space Center Houston, TX, United States)
Carl, J. R. (Lockheed Martin Corp. Houston, TX, United States)
Byerly, K.
Stolarcyzk, L.
Date Acquired
August 25, 2013
Publication Date
September 1, 2004
Publication Information
Publication: NASA Tech Briefs, September 2004
Subject Category
Man/System Technology And Life Support
Report/Patent Number
MSC-22839
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20110020517Collected WorksNASA Tech Briefs, September 2004
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