DocumentCode :
872505
Title :
Detection by Time Reversal: Single Antenna
Author :
Moura, José M F ; Jin, Yuanwei
Author_Institution :
Dept. of Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA
Volume :
55
Issue :
1
fYear :
2007
Firstpage :
187
Lastpage :
201
Abstract :
This paper studies the binary hypothesis test of detecting the presence or absence of a target in a highly cluttered environment by using time reversal. In time reversal, the backscatter of a signal transmitted into a scattering environment is recorded, delayed, energy normalized, and retransmitted through the medium. We consider two versions of the test-target channel frequency response assumed known or unknown-and, for each version, contrast two approaches: conventional detection (where no time reversal occurs) and time reversal detection. This leads to four alternative formulations for which we derive the optimal detector and the generalized likelihood ratio test, when the target channel frequency response is known or unknown, respectively. We derive analytical expressions for the error probabilities and the threshold for all detectors, with the exception of the time reversal generalized likelihood ratio test. Experiments with real-world electromagnetic data for two channels (free space with a target immersed in 20 scatterers and a duct channel) confirm the analytical results and show that time reversal detection provides significant gains over conventional detection. This gain is explained by the empirical distribution or type of the target channel frequency response-richer scattering channels induce types with heavier tails and larger time reversal detection gains
Keywords :
antennas; backscatter; error statistics; frequency response; binary hypothesis test; duct channel; energy normalization; error probability; generalized likelihood ratio test; optimal detector; reversal detection gains; scattering environment; signal transmission; single antenna; test-target channel frequency response; time reversal detection; Backscatter; Delay effects; Detectors; Ducts; Electromagnetic analysis; Electromagnetic scattering; Error probability; Frequency response; Probability distribution; Testing; Adaptive waveform; detection; empirical distribution; matched filter; time reversal; type; waveform reshape;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2006.882114
Filename :
4034211
Link To Document :
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