Sparse space-time adaptive array architecture

• US 10,054,666 B2
• Filed: 09/28/2015
• Issued: 08/21/2018
• Est. Priority Date: 09/26/2014
• Status: Active Grant

• Current Assignee: The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Vouras, Peter, De Graaf, Jean
• Primary Examiner(s): Windrich, Marcus E
• Application Number:
  US14/867,547
• Publication Number:
  US 20160091598A1
• Time in Patent Office: 1,058 Days
• Field of Search: 342 16, 342159
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures

Abstract

A sparse multichannel array includes a plurality of array elements, a receiver behind each array element, and a Doppler filter bank behind each receiver, whereby within each Doppler bin is placed spatial nulls at selected angles of undesired interference. The invention enables Doppler processing to be performed on sparse arrays, such as nested or coprime arrays, used in nonlinear adaptive beamforming to mitigate the impact of unintentional interference and hostile jamming on the received signal.

Claims

1. A sparse multichannel array, comprising:

a plurality of array elements;

a plurality of receivers, wherein each receiver in the plurality of receivers is behind a respective array element in the plurality of array elements;

a Doppler filter bank behind each receiver in the plurality of receivers, wherein respective Doppler bins of the Doppler filter bank have spatial nulls placed at selected angles of undesired interference; and

a signal processor coupled to respective outputs of the Doppler filter bank, wherein the signal processor is configured to perform nonlinear processing for each Doppler bin.

2. The array of claim 1, wherein the array is selected from nested or co-prime.

5. The sparse multichannel array of claim 1, wherein each receiver in the plurality of receivers comprises:

a downconverter configured to downconvert a signal to baseband; and

an analog-to-digital converter (ADC); and

a pulse compressor.

7. The sparse multichannel array of claim 1, wherein the spatial nulls are created in the Doppler filter bank by applying a weight to each array element in the plurality of array elements.

3. A sparse multichannel array, comprising:

a plurality of array elements;

a plurality of receivers, wherein each receiver in the plurality of receivers is behind a respective array element in the plurality of array elements;

a Doppler filter bank behind each receiver in the plurality of receivers, wherein respective Doppler bins of the Doppler filter bank have spatial nulls placed at selected angles of undesired interference; and

a signal processor coupled to respective outputs of the Doppler filter bank, wherein the signal processor is configured to;

perform nonlinear processing for each Doppler bin, and

determine respective adaptive outputs independently for each Doppler bin.

4. The array of claim 3, wherein the array is selected from nested or co-prime.

6. The sparse multichannel array of claim 3, wherein each receiver in the plurality of receivers comprises:

a downconverter configured to downconvert a signal to baseband; and

an analog-to-digital converter (ADC); and

a pulse compressor.

8. The sparse multichannel array of claim 3, wherein the signal processor is further configured to:

determine a steering vector based on the determined respective adaptive outputs.

9. The sparse multichannel array of claim 3, wherein the signal processor is configured to perform nonlinear spatially adaptive processing within each Doppler frequency bin.

10. A sparse multichannel array, comprising:

a plurality of array elements;

a plurality of receivers, wherein each receiver in the plurality of receivers is behind each a respective array element in the plurality of array elements;

a Doppler filter bank behind each receiver in the plurality of receivers, wherein respective Doppler bins of the Doppler filter bank have spatial nulls placed at selected angles of undesired interference; and

a signal processor coupled to respective outputs of the Doppler filter bank, wherein the signal processor is configured to;

determine respective Kronecker products for each Doppler bin,

retain distinct elements of the Kronecker products, and

determine a steering vector based on the retained distinct elements.

11. The sparse multichannel array of claim 10, wherein the steering vector is a steering vector of a difference co-array of a last Doppler bin of the respective Doppler bins.

12. The sparse multichannel array of claim 10, wherein the signal processor is further configured to compute an adaptive weight vector.

13. The sparse multichannel array of claim 12, wherein the signal processor is further configured to determine a spatially adapted pattern in the last Doppler bin based on the adaptive weight vector.

14. The sparse multichannel array of claim 12, wherein the spatial nulls are created in the Doppler filter bank by applying, based on the adaptive weight vector, a weight to each array element in the plurality of array elements.

15. The sparse multichannel array of claim 10, wherein each receiver in the plurality of receivers comprises:

a downconverter configured to downconvert a signal to baseband; and

an analog-to-digital converter (ADC); and

a pulse compressor.