Pressure sensitivity kernels applied to time-reversal acoustics.
Sensitivity kernels for receptions of broadband sound transmissions are used to study the effect of the transmitted signal on the sensitivity of the reception to environmental perturbations. A first-order Born approximation is used to obtain the pressure sensitivity of the received signal to small changes in medium sound speed. The pressure perturbation to the received signal caused by medium sound speed changes is expressed as a linear combination of single-frequency sensitivity kernels weighted by the signal in the frequency domain. This formulation can be used to predict the response of a source transmission to sound speed perturbations. The stability of time-reversal is studied and compared to that of a one-way transmission using sensitivity kernels. In the absence of multipath, a reduction in pressure sensitivity using time reversal is only obtained with multiple sources. This can be attributed both to the presence of independent paths and to cancellations that occur due to the overlap of sensitivity kernels for different source-receiver paths. The sensitivity kernel is then optimized to give a new source transmission scheme that takes into account knowledge of the medium statistics and is related to the regularized inverse filter.
Raghukumar
Kaustubha
K
Marine Physical Laboratory, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0238, USA. kaus@mpl.ucsd.edu
Cornuelle
Bruce D
BD
Hodgkiss
William S
WS
Kuperman
William A
WA
D000162:Acoustics; D004777:Environment; D006801:Humans; D008962:Models, Theoretical; D009792:Oceans and Seas; D011312:Pressure; D013017:Sound Localization; D013997:Time Factors