Acoustic positioning of oceanographic instruments

An acoustic technique for positioning oceanographic instruments in three dimensions at any point in the water column or on the ocean floor is described. The system utilizes an array of acoustic transponders on the sea floor and an acoustic source controlled by an internal clock installed on the device to be positioned. Particular consideration is given to the problem of operating such a system in areas of very rugged topography where direct acoustic paths from instrument to transponder may be obscured. Accuracy and repeatability of the technique utilizing both direct and surface reflected acoustic paths between instrument and transponder are examined experimentally. Results of an experiment to position a bottom sampling device utilizing such a multipath are presented.