Abstract: The method and apparatus for computing the range to and depth of a submerged object that either emits or reflects pulses of acoustic energy, wherein a detecting array and related data handling apparatus measure as a function of time the apparent angles of arrival of the acoustic energy associated with each such pulse. This data is then translated into actual multipath arrival angles and multipath travel time differences which are utilized to solve mathematical equations, the solutions of which result in the calculation of the range to and depth of the submerged source of acoustic energy.