Active towed array surface noise cancellation using a triplet cardioid

Patent metadata

Field	Value
Publication number	US-11450304-B2
Application number	US-202016806990-A
Country	US
Kind code	B2
Filing date	Mar 2, 2020
Priority date	Mar 2, 2020
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A sensor system includes a triplet element including a first hydrophone, a second hydrophone, and a third hydrophone configured to receive an incoming signal at a first phase, a second phase, and a third phase, respectively, the first to third hydrophones extending along a first direction, and a processor configured to determine an incidence direction of the incoming signal, and to dynamically generate a cardioid null in the incidence direction to reject the incoming signal based on the incoming signal at the first to third phases.

First claim

What is claimed is:

1. A sensor system comprising:
a triplet element comprising a first hydrophone, a second hydrophone, and a third hydrophone configured to receive an incoming signal at a first phase, a second phase, and a third phase, respectively, the first to third hydrophones extending along a first direction; and
a processor configured to determine an incidence direction of the incoming signal, and to dynamically generate a cardioid null in the incidence direction to reject the incoming signal based on the incoming signal at the first to third phases, the processor being further configured to determine an incidence direction of the incoming signal based on a depth of the triplet element, a water column depth, and a timing of transmission of a signal being reflected back from a seabed and a water surface as the incoming signal.

2. The sensor system of claim 1 , wherein the processor is configured to receive, without nullifying, other signals from directions different from the incidence direction of the incoming signal, the other signals being received by the triplet element at a same time as the incoming signal.

3. The sensor system of claim 1 , wherein the first phase is different from the second phase.

4. The sensor system of claim 1 , wherein the incoming signal is a surface reflection of an acoustic signal off of a seabed.

5. The sensor system of claim 1 , wherein one end of each of the hydrophones is positioned along a circumference of a circle.

6. The sensor system of claim 5 , wherein the first to third hydrophones are spaced at equal intervals.

7. The sensor system of claim 5 , wherein a radius of the circle is less than or equal to ⅙ of a wavelength of the incoming signal.

8. The sensor system of claim 1 , wherein the processor is further configured to determine a first incidence direction of the incoming signal at a first time, to determine a second incidence direction of the incoming signal at a second time, and to steer the cardioid null from the first incidence direction to the second incidence direction to reject the incoming signal over time.

9. A sensor system comprising:
a triplet element comprising a first hydrophone, a second hydrophone, and a third hydrophone configured to receive an incoming signal at a first phase, a second phase, and a third phase, respectively, the first to third hydrophones extending along a first direction; and
a processor configured to determine an incidence direction of the incoming signal, and to dynamically generate a cardioid null in the incidence direction to reject the incoming signal based on the incoming signal at the first to third phases,
wherein the processor is further configured to calculate an output response of the sensor system as a weighted summation of intensities of signals received at the first to third hydrophones, wherein weights of the weighted summation are based on a radius of the triplet element and an angular location of the cardioid null generated by the sensor system.

10. The sensor system of claim 1 , wherein the processor is further configured to calculate an output response of the sensor system as:

Output
⁡

(
θ
)

⁢

⁢

:=

⁢

⁢

20
·

log
⁡

[



∑

n
=
1

3

⁢

⁢

[

Phasor
⁡

(

X
n

,

Y
n

,
θ

)

·

α
n

·

e

-
2

·
π
·
i

λ

·

(

c
⁢

⁢

τ
n

)

]



]

where θ represents an incidence angle of the incoming signal, Phasor represents a signal seen by each of the hydrophones, X n and Y n represent coordinates of each of the hydrophones of the triplet element in a cross-plane orthogonal to the first direction, and

α
n

·

e

-
2

·
π
·
i

λ

·

(

c
⁢

Assignees

• Raytheon Co

Inventors

• Wilby Andrew

Classifications

• H04R2201/401

  2D or 3D arrays of transducers · CPC title

• G01V2210/1423

  Sea · CPC title

• G01V2210/56

  De-ghosting; Reverberation compensation · CPC title

• G01S3/8083

  determining direction of source · CPC title

• G01S3/86

  with means for eliminating undesired waves, e.g. disturbing noises · CPC title