ASA 127th Meeting M.I.T. 1994 June 6-10

4pUW7. Matched-field tracking of acoustic sources in shallow water.

Homer Bucker

NCCOSC, RTDE Div., Code 541, San Diego, CA 92152-5001

A simple matched-field tracking algorithm is proposed for transit detection of acoustic sources in shallow water. Let A and B represent the end points of a track. A track correlation function, C[sub AB], is calculated using the formula C[sub AB]=(summation)[sub f](summation)[sub t]{(Re (summation)[sub l](gamma)[sub l](gamma)[sub l][sup *])/[((summation)[sub l](gamma)[sub l](gamma)[sub l][sup *])((summation)(gamma)[sub l](gamma)[sub l][sup *])]}. In the equation above, the indices f, t, and l are for different frequencies, time periods, and sensor pairs, respectively, and the * denotes complex conjugate. The term (gamma) is the short period time average of the j,k element of the covariance matrix. That is, (gamma)[sub l]=, where F[sub j] is the signal received at sensor j. In a similar manner, (gamma)[sub l]=, where F[sub j] is the expected field if the acoustic source followed the track AB. Realistic simulations will be shown for detection of sound sources by a vertical line of sensors in a shallow water area with a sloping bottom.