Experimental demonstration of adaptive reverberation nulling using time reversal

The concept of environmentally adaptive reverberation nulling using a time reversal mirror (TRM) recently has been described [Song et al., J. Acoust. Soc. Am. 116, 762–768 (2004)]. In this paper, monostatic reverberation nulling is demonstrated experimentally at 850 and 3500Hz using data from a shallow water experiment conducted off the west coast of Italy in April 2003. The active transmission of a seafloor spatial null from a vertical source array is shown to result in the attenuation by 3–5dB of prominent reverberation features with their levels being reduced to that of the more diffuse reverberation background.