A mid-range 3D sonar

This paper describes a sonar system based on a hyperbolic-paraboloidal transducer beamformer. The array matrix composed of square sectioned elements is conformal to a doubly ruled surface of a hyperbolic paraboloid. The lines of elements in the array follow the surface rulings and are electrically configured to form multiple perpendicular linear array pairs. A multi-channel transmitter drives the transducer to ensonify an approximately square field of view of about 45 by 45 degrees either sequentially line by line or with a single ping. The multi-channel front end receiver allows simultaneous signal acquisition from receiver array lines. Unlike swath sounders, which rely on movement to build up a 3D image, this system is capable of generating a 3D image of the field while stationary. With a single channel transmitter and n-channel receiver it needs n pings to complete the image of the field. If wide band multichannel transmit-receive electronics is employed the number of pings required for full coverage can be reduced by introducing transmitted signal coding with subsequent discrimination of the received signals.