Side scan sonar system

Abstract

A side scan sonar system which records return echoes in a manner which realistically displays the spatial relationship between the sonar transducer and the echo producing topographical feature on the sea floor. The system includes a dual channel strip chart recorder having a continuous transverse belt carrying a pair of equally spaced writing styli. The belt circulates at a constant speed with each stylus moving across the paper, first in one direction and then in the opposite direction. One of the styli records starboard channel data when that stylus is moving across the paper toward the right, while the other stylus records port channel data when that stylus is moving across the paper toward the left. The channels may be recorded individually across the entire width of the paper, or they may be recorded simultaneously with the left going stylus recording the port channel from the center to the left edge of the paper, and the right going stylus recording the starboard channel from the center to the right edge of the paper. Belt guides are provided for spacing the transverse portions of the belt loop closely adjacent each other so that port channel data is plotted on approximately the same line along the length of the paper as the starboard channel data. A sonar pulse is transmitted when the writing styli are at a predetermined starting point on the paper, and the return echoes are plotted on the paper at a point spaced from the starting point a distance corresponding to the belt movement during the period from transmission of the sonar pulse to reception of the return signal.