Device for and a method of determining the angle of incidence of a received signal and a scanning sonar

A method of determining the angle of incidence of an incident ultrasonic signal by using an ultrasonic transducer constructed of a plurality of transducer elements which are arranged in multiple layers and columns, said method comprising the steps of:

• summing signals received by the individual transducer elements of columns centered on a specified scan azimuth for each layer to generate horizontally focused beam signals which provide high horizontal directivity;
• generating a vertical scan signal by sequentially selecting and combining the horizontally focused beam signals from the uppermost layer to the lowermost layer, or from the lowermost layer to the uppermost layer;
• and
• detecting the angle of incidence of the incident ultrasonic signal based on the amount of frequency shift of the vertical scan signal.

A scanning sonar for receiving echo signals by reception beams successively formed in azimuthal directions and for displaying received signals on an indicator comprising:

• an ultrasonic transducer constructed of a plurality of transducer elements which are arranged in multiple layers and columns;
• a horizontally focused beam former which sums signals received by the individual transducer elements of columns centered on a scan azimuth for each layer to generate horizontally focused beam signals which provide high horizontal directivity;
• a vertical scan signal former which generates a vertical scan signal by sequentially selecting and combining the horizontally focused beam signals from the uppermost layer to the lowermost layer, or from the lowermost layer to the uppermost layer;
• and
• an angle detector which detects the angle of incidence of an incident ultrasonic signal based on the amount of frequency shift of the vertical scan signal;
• a vertically focused beam former which sums signals received by the individual transducer elements of each column to generate vertically focused beam signals which provide high vertical directivity;
• a horizontal scan signal former which forms a horizontal scan signal by sequentially selecting and combining the vertically focused beam signals derived from the individual columns around the transducer;
• and
• a signal generator which takes out a signal from a specified direction based on the amount of frequency shift of the horizontal scan signal.

A scanning sonar comprising:

• an ultrasonic transducer constructed of a plurality of transducer elements which are arranged in multiple layers and columns;
• a horizontally focused beam former which sums signals received by the individual transducer elements of columns centered on a scan azimuth for each layer to generate horizontally focused beam signals which provide high horizontal directivity;
• a vertical scan signal former which generates a vertical scan signal by sequentially selecting and combining the horizontally focused beam signals from the uppermost layer to the lowermost layer, or from the lowermost layer to the uppermost layer;
• and
• an angle detector which detects the angle of incidence of an incident ultrasonic signal based on the amount of frequency shift of the vertical scan signal;
• a vertically focused beam former which sums signals received by the individual transducer elements of each column to generate vertically focused beam signals which provide high vertical directivity;
• a horizontal scan signal former which forms a horizontal scan signal by sequentially selecting and combining the vertically focused beam signals derived from the individual columns around the transducer;
• and
• a signal generator which takes out a signal from a specified direction based on the amount of frequency shift of the horizontal scan signal;
• wherein said vertically focused beam former, said horizontal scan signal former and said signal generator are activated in horizontal scan mode, and said horizontally focused beam former, said vertical scan signal former and said angle detector are activated in vertical scan mode.

A scanning sonar comprising:

• an ultrasonic transducer constructed of a plurality of transducer elements which are arranged in multiple layers and columns;
• a horizontally focused beam former which sums signals received by the individual transducer elements of a plurality of columns centered on a scan azimuth for each layer to generate horizontally focused beam signals which provide high horizontal directivity;
• a vertical scan signal former which generates a vertical scan signal by sequentially selecting and combining the horizontally focused beam signals from the uppermost layer to the lowermost layer, or from the lowermost layer to the uppermost layer;
• and
• a first detector receiving incoming signals based on the amount of frequency shift of the vertical scan signals;
• a vertically focused beam former which sums signals received by the individual transducer elements of each column to generate vertically focused beam signals which provide high vertical directivity;
• a horizontal scan signal former which forms a horizontal scan signal by sequentially selecting and combining the vertically focused beam signals derived from the individual columns around the transducer;
• and
• a second detector receiving incoming signals from directions based on the amount of frequency shift of the horizontal scan signals;
• and
• a display device displaying signals from said first detector or displaying signals from said second detector.