Compressive beamforming

Patent metadata

Field	Value
Publication number	US-9231303-B2
Application number	US-201313915670-A
Country	US
Kind code	B2
Filing date	Jun 12, 2013
Priority date	Jun 13, 2012
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A method of antenna array processing. Digitized time-series data from a plurality of antenna elements are divided into a plurality of time windows. A Fourier Transform is performed on a time window of the plurality of time windows for each antenna element of the plurality of antenna elements to generate a plurality of frequency domain vectors. The plurality of antenna elements is divided into a plurality of largest aperture sub-arrays. The frequency domain vectors are compressive beamformed tor the each sub-array to generate a plurality of bearing estimates corresponding to the plurality of sub-arrays. The plurality of bearing estimates from the plurality of sub-arrays are sparsely combined to generate a plurality of frequency-specific bearing estimates. The plurality of frequency-specific bearing estimates are incoherently averaged over a range of frequencies to generate a bearing for a bearing-timing record. A plurality of bearings for the bearing-timing record is generated.

First claim

What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A method of antenna array processing in an underwater environment exhibiting non-uniform noise, the method comprising:
providing an antenna array comprising a plurality of antenna elements, adjacent antenna elements of the plurality of antenna elements being uniformly spaced along the antenna array;
recording time-series data from the plurality of antenna elements;
digitizing the recorded time-series data;
dividing the digitized time-series data into a plurality of time windows;
performing a Fourier Transform on a time window of the plurality of time windows for each antenna element of the plurality of antenna elements to generate a plurality of frequency domain vectors;
dividing the plurality of antenna elements into a plurality of largest aperture sub-arrays, each sub-array of the plurality of equal aperture sub-arrays comprising non-uniformly spaced antenna elements from the antenna array;
compressive beamforming the frequency domain vectors for the each sub-array to generate a plurality of bearing estimates corresponding to the plurality of sub-arrays;
sparsely combining the plurality of bearing estimates from the plurality of sub-arrays to generate a plurality of frequency-specific bearing estimates;
incoherently averaging the plurality of frequency-specific bearing estimates over a range of frequencies to generate a bearing for a bearing-timing record;
repeating the performing a Fourier Transform on a time window, the dividing the plurality of antenna elements, the compressive beamforming the frequency domain vectors, and the incoherently averaging the plurality of frequency-specific bearing estimates to generate a plurality of bearings for the bearing-timing record; and
displaying an increment beamformer output based on the plurality of bearings for the bearing-timing record.

2. The method according to claim 1 , wherein the plurality of largest aperture sub-arrays satisfy the Uniform Uncertainty Principle.

3. The method according to claim 1 , wherein said compressive beamforming comprises beamforming free of a covariance matrix.

4. The method according to claim 3 , wherein said beamforming free of a covariance matrix comprises solving for a plurality of bearing angles using an I1 matrix inversion.

5. The method according to claim 4 , wherein said solving for a plurality of bearing angles using an I1 inversion comprises using one of a relaxation algorithm and a greedy algorithm.

6. The method according to claim 3 , wherein said beamforming free of a covariance matrix comprises solving for a plurality of bearing angles using an I1 matrix inversion and an I2 matrix inversion.

7. The method according to claim 1 , further comprising:
tracking at least one target using the displayed beamformer output.

8. The method according to claim 5 , further comprising:
classifying the at least one target based on the beamformer output.

9. The method according to claim 1 , wherein the antenna array is one of a ship-towed, horizontal array, a moored array, a conformal array, and a hull array.

10. The method according to claim 1 , wherein said sparsely combining the plurality of bearing estimates for the plurality of sub-arrays comprises selecting a plurality of minimum bearing estimates corresponding to a plurality of angles across a plurality of frequencies.

11. A method of antenna array processing in an underwater environment exhibiting non-uniform noise, the method comprising:
providing an antenna array comprising a plurality of antenna elements, adjacent antenna elements of the plurality of antenna elements being non-uniformly spaced along the antenna array;
recording time-series data from the plurality of antenna elements;
digitizing the recorded time-series data;
dividing the digitized time-series data into a plurality of time windows;
performing a Fourier Transform on a time window of the plurality of time windows for each antenna element of the plurality of antenna elements to generate a plurality of frequency domain vectors;
dividing the plurality of antenna elements into a plurality of largest aperture sub-arrays, each sub-array of the plurality of equal aperture sub-arrays comprising non-uniformly spaced antenna elements from the antenna array;
compressive beamforming the frequency domain vectors for the each sub-array to generate a plurality of bearing estimates corresponding to the plurality of sub-arrays;
sparsely combining the plurality of hearing estimates for the plurality of sub-arrays generate a plurality of frequency-specific bearing estimates;
incoherently averaging the plurality of frequency-specific bearing estimates over a range of frequencies to generate a bearing for a bearing-tinting record;
repeating the performing a Fourier Transform on a time window, the dividing the plurality of antenna elements, the compressive beamforming the frequency domain vectors, and the incoherently averaging the plurality of frequency-specific bearing estimates to generate a plurality of bearings for the bearing-timing record; and
displaying an increment beamformer output based on the plurality of bearings for the bearing-timing record.

12. The method according to claim 11 , wherein the plurality of largest aperture sub-arrays satisfy the Uniform Uncertainty Principle.

13. The method according to claim 11 , wherein said compressive beamforming comprises beamforming free of a covariance matrix.

14. The method according to claim 13 , wherein said beamforming free of a covariance matrix comprises solving for a plurality of bearing angles sing an I1 matrix inversion.

15. The method according to claim 14 , wherein said solving for a plurality of bearing angles using an I1 inversion comprises using one of a relaxation algorithm and a greedy algorithm.

16. The method according to claim 13 , wherein said beamforming free of a covariance matrix comprises solving for a plurality of bearing angles using an I1 matrix inversion and an I2 matrix inversion.

17. The method according to claim 11 , further comprising:
tracking at least one target using the displayed beamformer output.

18. The method according to claim 17 , further comprising:
classifying the at least one target based on the beamformer output.

19. The method according to claim 11 , wherein the antenna array is one of a ship-towed, horizontal array, a moored array, a conformal array, and a hull array.

20. The method according to claim 11 , wherein said sparsely combining the plurality of bearing estimates for the plurality of sub-arrays comprises selecting a plurality of minimum bearing estimates corresponding to a plurality of angles across a plurality of frequencies.

Assignees

• Edelmann Geoffrey F
• Gaumond Charles F
• Us Navy

Inventors

• Edelmann Geoffrey F
• Gaumond Charles F

Classifications

• G01S3/802 Primary

  Systems for determining direction or deviation from predetermined direction · CPC title

• G10K11/341

  Circuits therefor · CPC title

• G10K2200/11

  Underwater, e.g. transducers for generating acoustic waves underwater · CPC title

• H01Q3/34 Primary

  by electrical means (active lenses or reflecting arrays H01Q3/46) · CPC title

• G10K2200/10

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