Manual scan imaging sonar

A method of providing a video frame display of a sonar image of an underwater area to an operator using a portable self contained sonar device, said method comprising the steps of:

• scanning the underwater area with a single narrow beam sonar signal emitted from within a self contained sonar device;
• determining pitch and roll of the self contained sonar device;
• determining angle and angle rate of the self contained sonar device with a solid state angle sensor located within the self contained sonar device;
• determining compass bearing of the self contained sonar device with a solid state bearing sensor located within the self contained sonar device;
• storing and archiving displayed images with corresponding sonar device, range, bearing, reference bearing and positioning data;
• displaying the pitch and roll, thereby allowing the operator to keep the self contained sonar device level while scanning the single narrow beam sonar;
• producing said video frame display of the underwater area, said video frame display corrected for non-uniform movement of the self contained sonar device by processing and combining the angle, angle rate, and compass bearing information with digitized sonar data using a microcomputer contained within the self contained sonar device.

A manual scan self contained sonar device, comprising:

• a transmitter for developing and outputting an electrical signal having a number of cycles of a given frequency;
• a transducer coupled to said transmitter, said transducer for converting said electrical signal to transmitting acoustic waves, said transducer further for receiving and converting reflected acoustic waves into reflected signals;
• a receiver coupled to said transducer to condition said reflected signals;
• an A/D (analog to digital) converter coupled to said receiver to receive and convert said conditioned reflected signals;
• a microcomputer coupled to said A/D converter, said microcomputer for processing information obtained from said A/D converter;
• an angle rate sensor coupled to said A/D converter, said angle rate sensor for sensing angle rate movement of said self contained sonar device and to provide said angle rate movement to said A/D converter;
• an electronic compass coupled to said microcomputer to provide attitude information of said self contained sonar device to said microcomputer;
• a pitch and roll sensor coupled to said microcomputer to provide pitch and roll information of the self contained sonar device to said microcomputer.