Adaptive beamformer for sonar imaging

Patent metadata

Field	Value
Publication number	US-10024957-B2
Application number	US-201514857337-A
Country	US
Kind code	B2
Filing date	Sep 17, 2015
Priority date	Sep 17, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

Provided are method, system, and computer program product for imaging an underwater environment. The method may include receiving sonar returns and converting the sound energy of the sonar returns into sonar return data, and generating first beam data associated with a first beam having at least one first main lobe oriented in a first direction. Generating the first beam data may include: forming the sonar return data in the first direction; applying a first predetermined window to the sonar return data to define a first weighted return data; applying a second predetermined window to the sonar return data to define a second weighted return data; comparing a first power of the first weighted return data to a second power of the second weighted return data; and defining, when the first power is less than the second power, the first beam data based upon the first weighted return data.

First claim

The invention claimed is:

1. A method for adaptive beamforming, the method comprising:
receiving, via a transducer array, sonar returns from a sonar pulse transmitted into an underwater environment and converting the sound energy of the sonar returns into sonar return data, wherein the transducer array includes at least two transducer elements;
generating, via a sonar signal processor, a first beam data associated with a first beam based on the sonar return data, wherein the first beam defines at least one first main lobe oriented in a first direction, the generating comprising:
forming the sonar return data in the first direction;
applying a first predetermined window to the sonar return data to define first weighted return data, wherein the first predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the first weighted return data;
applying a second predetermined window to the sonar return data to define second weighted return data, wherein the second predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the second weighted return data;
comparing a first power of the first weighted return data to a second power of the second weighted return data; and
defining, in an instance in which the first power is less than the second power, the first beam data based upon the first weighted return data.

2. The method of claim 1 , further comprising:
generating a second beam data associated with a second beam based on the sonar return data, wherein the second beam defines at least one second main lobe oriented in a second direction, by:
forming the sonar return data in the second direction;
applying a third predetermined window to the sonar return data to define a third weighted return data, wherein the third predetermined window is configured to at least partially reduce the sonar return data outside the second direction in the third weighted return data;
applying a fourth predetermined window to the sonar return data to define a fourth weighted return data, wherein the fourth predetermined window is configured to at least partially reduce the sonar return data outside the second direction in the fourth weighted return data;
comparing a third power of the third weighted return data to a fourth power of the fourth weighted return data;
defining, in an instance in which the third power is less than the fourth power, the second beam data based upon the third weighted return data.

3. The method of claim 2 , wherein the first predetermined window is the same as the third predetermined window.

4. The method of claim 2 , wherein the first predetermined window is different from the third predetermined window.

5. The method of claim 1 , wherein the sonar return data is formed in the first direction for the first beam data by applying a phase shift to the sonar returns received by one or more of the at least two transducer elements to align the sonar returns received by each of the at least two transducer elements in the first direction.

6. The method of claim 1 , wherein the first predetermined window defines an average of a first plurality of predetermined windows, wherein the first plurality of predetermined windows includes at least a fifth predetermined window and a sixth predetermined window, wherein generating the first beam data further comprises:
applying the fifth predetermined window to the sonar return data to define a fifth weighted return data, wherein the fifth predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the fifth weighted return data;
applying the sixth predetermined window to the sonar return data to define a sixth weighted return data, wherein the sixth predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the sixth weighted return data;
comparing a fifth power of the fifth weighted return data to a sixth power of the sixth weighted return data; and
wherein, in an instance in which the fifth power is less than the sixth power, defining the first beam data based upon the first weighted return data further comprises defining the first beam data based upon the fifth weighted return data.

7. The method of claim 6 , wherein comparing the fifth power of the fifth weighted return data to the sixth power of the sixth weighted return data further comprises comparing the first power of the first weighted return data to the fifth power and the sixth power, such that in an instance in which the fifth power is less than the sixth power and the first power, the first beam data is based upon the fifth weighted return data.

8. The method of claim 6 , wherein the second predetermined window defines an average of a second plurality of predetermined windows.

9. The method of claim 6 , wherein first plurality of predetermined windows comprises eight predetermined windows, including the fifth predetermined window and the sixth predetermined window.

10. The method of claim 7 , wherein the second plurality of predetermined windows comprises eight predetermined windows.

11. The method of claim 1 , wherein the first main lobe is symmetric about the first direction.

12. The method of claim 1 , wherein the first main lobe is offset from the first direction.

13. The method of claim 1 , wherein the first predetermined window comprises unit gain in the first direction.

14. The method of claim 13 , wherein the second predetermined window comprises unit gain in the first direction.

15. The method of claim 1 , wherein the first beam defines at least one null adjacent the first main lobe.

16. The method of claim 1 , further comprising displaying, via a display, an image based upon position data from the first beam data.

17. The method of claim 1 , wherein the transducer array defines a first row of transducer elements and a second row of transducer elements;
wherein the first row of transducer elements is configured to generate the first beam data associated with the first beam;
wherein the first row of transducer elements is disposed proximate the second row of transducer elements such that a first transducer element in the first row is positioned in the housing at a predetermined distance from a first transducer element of the second row of transducer elements and a second transducer element of the first row is positioned in the housing at the predetermined distance from a second transducer element of the second row;
wherein the method further comprises:
generating a second beam data associated with a second beam based on the sonar return data received by the second row of transducer elements, wherein the second beam defines at least one second main lobe oriented in the first direction, the generating comprising:
forming the sonar return data received by the second row of transducer elements in the first direction;
applying a third predetermined window to the sonar return data received by the second row of transducer elements to define third weighted return data, wherein the third predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the third weighted return data;
applying a fourth predetermined window to the sonar return data received by the second row of transducer elements to define fourth weighted return data, wherein the fourth predetermined window is configured to at least partially reduce the sonar return data outside the first direction in the fourth weighted ret

Assignees

• Navico Holding As

Inventors

• Horner Ronald Joe

Classifications

• G01S15/89

  for mapping or imaging · CPC title

• G01S7/6245

  Stereoscopic displays; Three-dimensional displays; Pseudo-three dimensional displays · CPC title

• G01S7/52003 Primary

  Techniques for enhancing spatial resolution of targets (G01S7/52046 takes precedence) · CPC title

• G01S7/526

  Receivers · CPC title

• G10K2200/10

  Beamforming, e.g. time reversal, phase conjugation or similar · CPC title