Acoustic tracking system

An acoustic tracking system for a remote signal source emitting signals of predetermined frequencies, said system comprising:

• an array of sound sensitive units mounted on a body in the medium in which the signals are being propagated, said units receiving and converting the acoustic signals to electrical signals, the spacing between adjacent said units being equal to or greater than one-half the wavelength of the signals;
• receiver means mounted on said body;
• means for transmitting the electrical signals from said sound sensitive units to said receiver means;
• and
• signal processing means in said receiver means to unambiguously determine the time difference of arrival of a complex signal at each adjacent pair of said units and thereby determine the bearing from the body to the signal source.

A method for acoustically tracking sound emitting cetaceans, said method comprising the steps of:

• mounting an array of a plurality of sound sensitive units on an ocean-going vessel having a keel and chine on either side of the keel;
• moving the vessel and array to the vicinity of acoustic signal producing cetaceans;
• receiving such acoustic signals by the plurality of sound sensitive units;
• converting tire acoustic signals to electrical signals;
• transferring such electrical signals to a receiver;
• calculating tire relative range and bearing from the vessel to the acoustic signal producing cetaceans;
• and
• providing indications of the calculated range and bearing.

A method for acoustically tracking a remote signal source emitting signals of predetermined frequencies, said method comprising the steps of:

• mounting an array of pairs of sound sensitive units in mutual fixed relationship on a body in the medium in which the signals are being propagated;
• receiving the signals by the sound sensitive units, the spacing between the units in each pair being equal to or greater than one-half the wavelength of the signals;
• converting the received signals to electrical signals;
• transmitting the electrical signals to a receiver;
• and
• determining in an unambiguous manner the time difference of arrival of a complex signal at each unit in each pair of units and thereby determining the bearing from the body to the signal source.