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Experimental subwavelength localization of scatterers by decomposition of the time reversal operator interpreted as a covariance matrix

2003; Acoustical Society of America; Volume: 114; Issue: 1 Linguagem: Inglês

10.1121/1.1568759

1520-9024

Claire Prada, Jean-Louis Thomas,

Underwater Acoustics Research

The D.O.R.T. method (French acronym for Decomposition of the Time Reversal Operator) is an active remote sensing technique using arrays of antennas for the detection and localization of scatterers [Prada et al., J. Acoust. Soc. Am. 99, 2067–2076 (1996)]. The analogy between the time reversal operator and the covariance matrix used for classical sources separation in passive remote sensing [Bienvenu et al., IEEE Trans. ASSP 31, 1235–1247 (1983)] is established. Then, an experiment of subwavelength detection and localization of point-like scatterers with a linear array of transducers is presented. Using classical estimators in reception like Maximum-Likelihood and Multiple Signal Characterization (MUSIC), two point-like scatterers separated by λ/3 and placed at 100λ from the array of transducers are resolved. In these experiments, the role of multiple scattering and the existence of additional eigenvectors associated with dipolar and monopolar radiation of each scatterer is discussed.