Abstract: An autonomous hydrophone position locating and target tracking system employing a string or array of acoustic hydrophone equipped apparatuses that are easily and rapidly deployed over the ocean bottom within a preselected volume of water. For each bottom residing hydrophone, a dedicated cable provides surface location based on satellite generated GPS positioning data. Special real time cable deflection algorithms resident in the base unit electronic processor are continuously updated using the velocity gradient inputs from several in-line velocimeters positioned at different depths along the cable. The shape of the tether cable and the resulting position of the bottom unit mounted hydrophone is then back calculated in real time in three dimensions from the known global position of the surface buoy.