BEAMFORMING TECHNIQUES IMPLEMENTING THE ITERATIVE ADAPTIVE APPROACH (IAA)

• US 20200136250A1
• Filed: 12/23/2019
• Published: 04/30/2020
• Est. Priority Date: 12/23/2019
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Cohen, Alon, Maor, Lior, Teplitsky, Moshe, Yoffe, Ilia
• Granted Patent: US 11,532,883 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 13/4481 Monopulse hybrid systems, e.g. conopulse
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/03 Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
• CPC Class Codes: H01Q 21/22 Antenna units of the array energised non-uniformly in amplitude or phase, e.g. tapered array or binomial array
• CPC Class Codes: H01Q 3/2694 using also variable phase-shifters H01Q3/2688 takes precedence

Abstract

Techniques are disclosed implementing two alternative approaches for adaptive beamforming for MIMO radar. The first of these includes a “reduced complexity” iterative adaptive approach (RC-IAA) algorithm, which uses two steps including a delay-and-sum beamforming step (DAS-BF) and an IAA step that is applied to the output generated by the DAS-BF step. A second technique is described that includes a “beam space” iterative adaptive approach (BS-IAA) algorithm, which uses three steps including a delay-and-sum beamforming step (DAS-BF), a region of interest (ROI) detection step that is applied to the output generated by the DAS-BF, and an IAA step that is applied to detected ROIs.

Claims

1. A method of performing beamforming, comprising:

applying matched filtering to each of a plurality of received signals to generate a virtual antenna array output for a multiple-input multiple-output (MIMO) radar system;

performing, using the virtual antenna array output, delay-and-sum (DAS) beamforming to generate an initial power spectrum estimation associated with the plurality of received signals; and

generating beamforming data based on an iterative adaptive approach (IAA) that includes a number of iterations using the initial power spectrum estimation as an initial power estimation, and iteratively updating and evaluating the initial power estimation in one of a plurality of different beam directions.

2. The method of claim 1, wherein the MIMO radar system includes a number of transmit antennas Ntx, and a number of receive antennas Nrx, and wherein the virtual antenna array output has a size equal to a multiplication of the number of transmit antennas and the number or receive antennas (Ntx)(Nrx).

3. The method of claim 2, wherein the initial power spectrum estimation comprises a size equal to the number of receive antennas Nrx.

4. The method of claim 1, wherein generating the beamforming data includes initially estimating a covariance (COV) matrix using the initial power spectrum estimation, and iteratively re-estimating the COV matrix as the initial power estimation is iteratively updated and evaluated.

5. The method of claim 1, wherein generating the beamforming data includes, for each of the number of iterations, updating and evaluating the initial power estimation in one of the plurality of different beam directions over a predetermined number of spectrum samples.

6. The method of claim 1, wherein generating the beamforming data includes repeating updating and evaluating the initial power estimation for each one of the plurality of different beam directions for each of the plurality of different beam directions.

7. A non-transitory computer-readable media having instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform beamforming by:

applying matched filtering to each of a plurality of received signals to generate a virtual antenna array output for a multiple-input multiple-output (MIMO) radar system;

performing, using the virtual antenna array output, delay-and-sum (DAS) beamforming to generate an initial power spectrum estimation associated with the plurality of received signals; and

generating beamforming data based on an iterative adaptive approach (IAA) for a number of iterations using the initial power spectrum estimation as an initial power estimation, and evaluating the initial power estimation in one of a plurality of different beam directions.

8. The non-transitory computer-readable media of claim 7, wherein the MIMO radar system includes a number of transmit antennas Ntx, and a number of receive antennas Nrx, and wherein the virtual antenna array output has a size equal to a multiplication of the number of transmit antennas and the number of receive antennas (Ntx)(Nrx).

9. The non-transitory computer-readable media of claim 8, wherein the initial power spectrum estimation comprises a size equal to the number of receive antennas Nrx.

10. The non-transitory computer-readable media of claim 7, wherein the instructions further cause the one or more processors to generate the beamforming data by initially estimating a covariance (COV) matrix using the initial power spectrum estimation, and iteratively re-estimating the COV matrix as the initial power estimation is iteratively updated and evaluated.

11. The non-transitory computer-readable media of claim 7, wherein the instructions further cause the one or more processors to generate the beamforming data by, for each of the number of iterations, updating and evaluating the initial power estimation in one of the plurality of different beam directions over a predetermined number of spectrum samples.

12. The non-transitory computer-readable media of claim 7, wherein the instructions further cause the one or more processors to generate the beamforming data by repeating the updating and evaluating of the initial power estimation for each one of the plurality of different beam directions for each of the plurality of different beam directions.

13. A method of performing beamforming, comprising:

applying matched filtering to each of a plurality of received signals to generate a virtual antenna array output for a multiple-input multiple-output (MIMO) radar system;

performing, using the virtual antenna array output, delay-and-sum (DAS) beamforming to generate an initial power spectrum estimation associated with the plurality of received signals;

identifying one or more regions of interest (ROIs) in beam space using the initial power spectrum estimation, the one or more ROIs including one or more beam sectors associated with a detected target based upon a beam power exceeding a detection threshold value; and

generating beamforming data based on an iterative adaptive approach by using, for each identified ROI from among the one or more identified ROIs, the initial power spectrum estimation as an initial power estimation in beam space and, for each of a number of iterations for each ROI, iteratively updating the initial power estimation until a power estimation is performed for each active beam sector associated with each of the one or more identified ROIs.

14. The method of claim 13, wherein the act of identifying the one or more ROIs includes an ordered-statistic constant false-alarm rate (OS-CFAR) detection.

15. The method of claim 13, wherein each one of the one or more ROIs is based upon a region in beam space formed around a portion of a respective beam having a power that exceeds the detection threshold value.

16. The method of claim 13, wherein each one of the one or more ROIs has a respective beam width that is based upon a beam pattern generated as a result of the DAS beamforming.

17. The method of claim 13, wherein the MIMO radar system includes a number of transmit antennas Ntx, and a number of receive antennas Nrx, and wherein the virtual antenna array output has a size equal to a multiplication of the number of receive antennas by the number of transmit antennas (Ntx)(Nrx).

18. The method of claim 17, wherein the initial power spectrum estimation comprises a size equal to the number of receive antennas Nrx.

19. A non-transitory computer-readable media having instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform beamforming by:

applying matched filtering to each of a plurality of received signals to generate a virtual antenna array output for a multiple-input multiple-output (MIMO) radar system;

performing, using the virtual antenna array output, delay-and-sum (DAS) beamforming to generate an initial power spectrum estimation associated with the plurality of received signals;

identifying one or more regions of interest (ROIs) in beam space using the initial power spectrum estimation, the one or more ROIs including one or more beam sectors associated with a detected target based upon a beam power exceeding a detection threshold value; and

generating beamforming data based on an iterative adaptive approach (IAA) approach using, for each identified ROI from among the one or more identified ROIs, the initial power spectrum estimation as an initial power estimation in beam space and, for each of a number of iterations for each ROI, iteratively updating the initial power estimation until a power estimation is performed for each of active beam sector associated with each of the one or more identified ROIs.

20. The non-transitory computer-readable media of claim 19, wherein the instructions further cause the one or more processors to identify the one or more ROIs using an ordered-statistic constant false-alarm rate (OS-CFAR) detection.

21. The non-transitory computer-readable media of claim 19, wherein the instructions further cause the one or more processors to identify the one or more ROIs based upon a region in beam space formed around a portion of a respective beam having a power that exceeds the detection threshold value.

22. The non-transitory computer-readable media of claim 19, wherein the instructions further cause the one or more processors to identify the one or more ROIs having a respective beam width that is based upon a beam pattern generated as a result of the DAS beamforming.

23. The non-transitory computer-readable media of claim 19, wherein the MIMO radar system includes a number of transmit antennas Ntx, and a number of receive antennas Nrx, and wherein the virtual antenna array output has a size equal to multiplication of the number of receive antennas by the number of transmit antennas (Ntx)(Nrx).

24. The non-transitory computer-readable media of claim 23, wherein the initial power spectrum estimation comprises a size equal to the number of receive antennas Nrx.