Patent ID: 8305840

Claim:
A sonar assembly for imaging an underwater environment beneath a watercraft traveling on a surface of a body of water, the sonar assembly comprising: a housing mountable to the watercraft; a single linear downscan transducer element positioned within the housing, the linear downscan transducer element having a substantially rectangular shape configured to produce a fan-shaped sonar beam having a relatively narrow beamwidth in a direction parallel to a longitudinal length of the linear downscan transducer element and a relatively wide beamwidth in a direction perpendicular to the longitudinal length of the transducer element, the linear downscan transducer element being positioned with the longitudinal length thereof extending in a fore-to-aft direction of the housing; wherein the linear downscan transducer element is positioned within the housing to project fan-shaped sonar beams in a direction substantially perpendicular to a plane corresponding to the surface of the body of water, said sonar beams being repeatedly emitted so as to sequentially insonify different fan-shaped regions of the underwater environment as the watercraft travels; and a sonar signal processor receiving signals representative of sonar returns resulting from each of the fan-shaped sonar beams and processing the signals to produce sonar image data for each fan-shaped region and to create an image of the underwater environment as a composite of images of the fan-shaped regions arranged in a progressive order corresponding to the travel of the watercraft.