ASA 126th Meeting Denver 1993 October 4-8

4pUW10. Minimum entropy deconvolution of underwater acoustic transients.

Michael K. Broadhead

Naval Res. Lab., Code 7173, Stennis Space Center, MS 39529-5004

The minimum entropy deconvolution (MED) method [R. Wiggins, Geoexploration 16, 21--35 (1978)], is used to produce source signature estimates from underwater acoustic transients, which has application in the passive sonar classification problem. The Green's function, representing environmental distortion effects, is treated as a non-Gaussian random process. The MED method implemented in this paper leads to a one-parameter model that doesn't require accurate knowledge of the source location and environmental parameters, or the computation of Green's functions. Results from applying the MED method to single-sensor, broadband ocean acoustic measurements are shown, where source signature estimate correlation coefficients range between 0.87 to 0.91. The method is also applied to realistic simulations, produced with a parabolic equation (PE) model, using a source pulse that was longer and more complex than the measured source. Source signature estimate correlation coefficients ranged between 0.95 and 0.99. The technique assumes that the input random process is non-Gaussian, which is justified by high kurtosis values of the computed (PE) Green's functions associated with this data set. [Work supported by Office of Naval Research, with technical management provided by the Naval Research Laboratory.]