Active waveguide Green's function estimation with application to time-reversal focusing without a probe source in a range-independent waveguide

S.C. Walker (1) , W.A. Kuperman (1) , P. Roux (2)

1 Marine Physical Laboratory of the Scripps Institution of Oceanography
2 LGIT - Laboratoire de Géophysique Interne et Tectonophysique

A method is introduced for using a pair of vertical line transducer arrays (VLAs) to produce time-reversal (TR) foci at any location in a range-independent shallow-ocean waveguide without the need for a probe source. Modal theory suggests that the acoustic response sampled between a pair of VLAs separated by a range R can be repeatedly iterated to estimate the acoustic response at ranges that are integer multiples of R. When combined with the frequency-based variable-range-TR method, the process results in a virtual sampling of the acoustic response over long distances that can be applied to both passive and active shallow-ocean acoustic imaging. Here, the technique is applied to active time-reversal focusing. Array geometry effects are explored and simulation and experimental results are presented.

S.C. Walker, W.A. Kuperman, P. Roux. Active waveguide Green's function estimation with application to time-reversal focusing without a probe source in a range-independent waveguide. Journal of the Acoustical Society of America, 2006, 120 (5), pp.2755-2763. ⟨10.1121/1.2355538⟩. ⟨insu-00270312⟩