Beamforming sonar system with improved sonar image functionality, and associated methods

A transducer assembly mountable to a watercraft for imaging an underwater environment of a body of water, the transducer assembly comprising:

• a single array of a plurality of transducer elements, wherein the single array of the plurality of transducer elements is configured to be oriented with an emitting face in a facing direction that is generally forward and downward of the watercraft,
• wherein the emitting face of the single array of the plurality of transducer elements defines a width and a length, wherein the length of the emitting face is greater than the width of the emitting face, and wherein the length of the emitting face extends in a fore-to-aft direction of the watercraft, wherein the facing direction is perpendicular to the emitting face,
• wherein each of the plurality of transducer elements defines a length and a width, wherein the length of each of the plurality of transducer elements is greater than the width of each of the plurality of transducer elements, wherein the length of each of the plurality of transducer elements is perpendicular to the length of the emitting face,
• wherein the plurality of transducer elements are configured to transmit one or more sonar beams into the underwater environment, and
• wherein the single array of the plurality of transducer elements is configured to operate each of the plurality of transducer elements at a fixed phase shift and vary in frequency so as to beamform multiple sonar return beams across the emitting face between a first range of angles in the fore-to-aft direction and between a second range of angles in the fore-to-aft direction, wherein the first range of angles is symmetrical to the second range of angles with respect to the facing direction, and wherein a gap of a third range of angles in the fore-to-aft direction separates the first range of angles and the second range of angles, wherein the first range of angles cover a generally downward direction from the watercraft, wherein the second range of angles cover a generally forward and downward direction from the watercraft;
• and
• a sonar signal processor in communication with the single array and configured to:
• cause operation of the plurality of transducer elements to transmit the one or more sonar beams into the underwater environment;
• receive sonar return data from the plurality of transducer elements of the array;
• filter the sonar return data based on frequency to form the multiple sonar return beams;
• determine a plurality of the multiple sonar return beams that correspond to a fourth range of angles in the fore-to-aft direction including an angle within the first range of angles that is substantially straight downward from the watercraft, wherein the plurality of the multiple sonar return beams form a beam shape that is defined by a fore-to-aft angle within a range of 10°-45° in the fore-to-aft direction and a port-to-starboard angle within a range of 10°-27° in a port-to-starboard direction, wherein the fore-to-aft angle is the fourth range of angles that corresponds to the determined plurality of the multiple sonar return beams;
• determine one or more of the multiple sonar return beams that includes the angle within the first range of angles that is substantially straight downward from the watercraft, wherein the one or more of the multiple sonar return beams form a fan-shaped beam that is defined by a fore-to-aft angle within a range of 0.5°-3° in the fore-to-aft direction and a port-to-starboard angle within a range of 10°-27° in the port-to-starboard direction, wherein the fore-to-aft angle is the angle within the first range of angles that corresponds to the determined one or more of the multiple sonar return beams, wherein the one or more of the multiple sonar return beams is less than the plurality of the multiple sonar return beams that correspond to the fourth range of angles;
• generate a first sonar image of the underwater environment forward and downward from the watercraft, wherein the first sonar image is a forward two-dimensional live sonar image that is formed of sonar return data from multiple sonar return beams that correspond to the second range of angles, and wherein the sonar return data used to form the forward two-dimensional live sonar image was received at substantially a same time by the plurality of transducer elements;
• generate a second sonar image of the underwater environment downward from the watercraft, wherein the second sonar image is a downward two-dimensional live sonar image that is formed of sonar return data from multiple sonar return beams that correspond to the first range of angles, and wherein the sonar return data used to form the downward two-dimensional live sonar image was received at substantially a same time by the plurality of transducer elements;
• generate a third sonar image of the underwater environment downward from the watercraft, wherein the third sonar image is formed from the determined plurality of the multiple sonar return beams that corresponds to the fourth range of angles, wherein the third sonar image is formed of a plurality of sonar image portions built up over time, wherein each of the plurality of sonar image portions corresponds to sonar return data from the determined plurality of the multiple sonar return beams received at different times;
• and
• generate a fourth sonar image of the underwater environment downward from the watercraft, wherein the fourth sonar image is formed from the determined one or more of the multiple sonar return beams that includes the angle within the first range of angles that is substantially straight downward from the watercraft, wherein the fourth sonar image is formed of a plurality of sonar image portions built up over time, wherein each of the plurality of sonar image portions corresponds to sonar return data from the determined one or more of the multiple sonar return beams received at different times.

A system for imaging an underwater environment of a body of water, the system comprising:

• a single array of a plurality of transducer elements mountable to a watercraft for use on the body of water, wherein, when mounted, the single array of the plurality of transducer elements is configured to be oriented with an emitting face in a facing direction that is generally forward and downward of the watercraft,
• wherein the emitting face of the single array of the plurality of transducer elements defines a width and a length, wherein the length of the emitting face is greater than the width of the emitting face, and wherein the length of the emitting face extends in a fore-to-aft direction of the watercraft, wherein the facing direction is perpendicular to the emitting face,
• wherein the plurality of transducer elements are configured to transmit one or more sonar beams into the underwater environment by being operated at a fixed phase shift and varying in frequency so as to enable beamforming of multiple sonar return beams across the emitting face across a first range of angles in the fore-to-aft direction and across a second range of angles in the fore-to-aft direction, wherein the first range of angles cover a generally downward direction from the watercraft, wherein the second range of angles cover a generally forward and downward direction from the watercraft;
• and
• a sonar signal processor in communication with the plurality of transducer elements and configured to:
• cause operation of the plurality of transducer elements to transmit the one or more sonar beams into the underwater environment;
• receive sonar return data from the plurality of transducer elements;
• determine a plurality of the multiple sonar return beams from within the first range of angles that cover at least a substantially straight downward direction from the watercraft and form a beam shape that is defined by a fore-to-aft angle within a range of 10°-45° in the fore-to-aft direction and a port-to-starboard angle within a range of 10°-27° in a port-to-starboard direction, wherein the fore-to-aft angle is the angle within the first range of angles that corresponds to the determined plurality of the multiple sonar return beams;
• determine one or more of the multiple sonar return beams from within the first range of angles that cover at least the substantially straight downward direction from the watercraft and form a fan-shaped beam that is defined by a fore-to-aft angle within a range of 0.5°-3° in the fore-to-aft direction and a port-to-starboard angle within a range of 10°-27° in the port-to-starboard direction, wherein the fore-to-aft angle is the angle within the first range of angles that corresponds to the determined one or more of the multiple sonar return beams;
• generate a first sonar image of the underwater environment forward and downward from the watercraft, wherein the first sonar image is a forward two-dimensional live sonar image that is formed of sonar return data from multiple sonar return beams that correspond to the second range of angles, and wherein the sonar return data used to form the forward two-dimensional live sonar image was received at substantially a same time by the plurality of transducer elements;
• generate a second sonar image of the underwater environment downward from the watercraft, wherein the second sonar image is a downward two-dimensional live sonar image that is formed of sonar return data from multiple sonar return beams that correspond to the first range of angles, and wherein the sonar return data used to form the downward two-dimensional live sonar image was received at substantially a same time by the plurality of transducer elements;
• generate a third sonar image of the underwater environment downward from the watercraft, wherein the third sonar image is formed from the determined plurality of the multiple sonar return beams, wherein the third sonar image is formed of a plurality of sonar image portions built up over time, wherein each of the plurality of sonar image portions corresponds to sonar return data from the determined plurality of the multiple sonar return beams received at different times;
• and
• generate a fourth sonar image of the underwater environment downward from the watercraft, wherein the fourth sonar image is formed from the determined one or more of the multiple sonar return, wherein the fourth sonar image is formed of a plurality of sonar image portions built up over time, wherein each of the plurality of sonar image portions corresponds to sonar return data from the determined one or more of the multiple sonar return beams received at different times.