Underwater camera positioning by sonar

Abstract

A pulse sonar system is described for measuring the height above the bottom of an underwater camera and other equipment in the deep oceans. Using this method, cameras have been positioned for photography at depths to about 2,500 fathoms with a precision of about half a fathom. The measurement is achieved by a sonar "pinger" on the equipment, which sends precise 1 pulse-per- second signals to the surface both directly and by reflection from the bottom.