Sound source location by difference of phase, on a hydrophone array with small dimensions

A method for localizing calling animals was tested at the Research and Educ ation Center Dolphins Plus in Key Large, FL, under realistic field conditio ns. Experiments were performed with bottlenose dolphins (Tursiops truncatus ) using a special hydrophone arrangement. There were two groups of hydropho nes, and the two hydrophones in each group were 15 cm apart. The groups wer e separated by a distance of 15 m. Acoustic signals from the animals were r ecorded by use of a digital data acquisition system with a sampling rate of 1 MHz. All data were processed off-line. The time delay was measured by th e phase difference in a single wavelength on whistles and clicks. The beari ng of the signals was calculated with help of the time delay. This method h as high precision and provides the possibility for analyzing overlapped sig nals. (C) 2001 Acoustical Society of America.