Matched-field tracking of acoustic sources in shallow water

Abstract

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, CAB, is calculated using the formula CAB= ∑f∑t{(Re ∑lγlγ̂*l) /[(∑lγlγ̂*l) (∑γ̂lγ̂*l)]}. 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 γ is the short period time average of the j,k element of the covariance matrix. That is, γl=〈FjF*k〉, where Fj is the signal received at sensor j. In a similar manner, γ̂l=〈F̂jF̂*k〉, where Fj 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.