Radar hardware accelerator

• US 10,330,773 B2
• Filed: 06/16/2016
• Issued: 06/25/2019
• Est. Priority Date: 06/16/2016
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Rao, Sandeep, Ramasubramanian, Karthik, Prathapan, Indu, Ganesan, Raghu, Gupta, Pankaj
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US15/184,715
• Publication Number:
  US 20170363711A1
• Time in Patent Office: 1,104 Days
• Field of Search: 342 93
• CPC Class Codes: G01S 13/34 using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• 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 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04L 27/103 Chirp modulation for spread spectrum techniques H04B1/69

Abstract

A radar hardware accelerator (HWA) includes a fast Fourier transform (FFT) engine including a pre-processing block for providing interference mitigation and/or multiplying a radar data sample stream received from ADC buffers within a split accelerator local memory that also includes output buffers by a pre-programmed complex scalar or a specified sample from an internal look-up table (LUT) to generate pre-processed samples. A windowing plus FFT block (windowed FFT block) is for multiply the pre-processed samples by a window vector and then processing by an FFT block for performing a FFT to generate Fourier transformed samples. A post-processing block is for computing a magnitude of the Fourier transformed samples and performing a data compression operation for generating post-processed radar data. The pre-processing block, windowed FFT block and post-processing block are connected in one streaming series data path.

Claims

1. A radar hardware accelerator (HWA), comprising:

a fast Fourier transform (FFT) engine including;

a pre-processing block for providing at least one of interference mitigation, finite impulse response (FIR) filtering and multiplying a radar data sample stream received from ADC buffers within a split accelerator local memory that also includes output buffers by a pre-programmed complex scalar or a specified sample from an internal look-up table (LUT) to generate pre-processed samples;

a windowing plus FFT block (windowed FFT block) for multiplying said pre-processed samples by a window vector and then processing by an FFT block for performing a FFT to generate Fourier transformed samples;

a post-processing block for computing a magnitude of said Fourier transformed samples; and

wherein said pre-processing block, said windowed FFT block, and said post-processing block are connected in one streaming series data path.

2. The HWA of claim 1, further comprising a constant false alarm rate (CFAR) engine in a CFAR detection path parallel to said streaming series data path including a log-magnitude pre-processing block and a CFAR detector for detecting radar target returns against a background.

3. The HWA of claim 2, wherein said CFAR detection path shares at least one of a shared memory and logic with said FFT engine.

4. The HWA of claim 1, wherein said pre-processing block, said windowed FFT block and said post-processing block include independent enable (EN) circuits to provide independent muxing controls that enable/bypass for any combination of said pre-processing block, said windowed FFT block and said post-processing block.

5. The HWA of claim 1, further comprising a substrate that provides at least a semiconductor surface, wherein said HWA is formed in said semiconductor surface.

6. The HWA of claim 1, wherein said ADC buffers and said output buffers are both split memories.

7. A radar sub-system, comprising:

a split accelerator local memory including ADC input buffers (ADC buffers) for storing radar data sample streams, and output buffers;

a radar hardware accelerator (HWA) coupled to said ADC buffers for receiving said radar data sample streams and for processing said radar data sample streams, said HWA including;

a fast Fourier transform (FFT) engine including;

a pre-processing block for providing at least one of interference mitigation, finite impulse response (FIR) filtering and multiplying said radar data sample streams by a pre-programmed complex scalar or a specified sample from an internal look-up table (LUT) to generate pre-processed samples;

a windowing plus FFT block (windowed FFT block) for multiplying said pre-processed samples by a window vector and then processing by an FFT block for performing a FFT to generate Fourier transformed samples;

a post-processing block for computing a magnitude of said Fourier transformed samples for generating post-processed radar data, wherein said pre-processing block, said windowed FFT block, and said post-processing block are connected in one streaming series data path, and wherein an output of said post-processing block is coupled to an input of said output buffers for transferring said post-processed radar data to said output buffers, and

a parameter-set configuration memory coupled to a state machine both coupled by a bus to said FFT engine for sequencing parameters sets for execution of a chained sequence of operations and data transfers between said accelerator local memory and an external memory for controlling said pre-processing block, said windowed FFT block and said post-processing block.

8. The radar sub-system of claim 7, wherein said state machine is a parameter-set based state machine wherein said parameter-sets are programmable, said parameter-sets for configuring said HWA to perform a certain set of said operations, and wherein a sequence of executing said parameter-sets is defined.

9. The radar sub-system of claim 7, further comprising a constant false alarm rate (CFAR) engine in a CFAR detection path parallel to said streaming series data path including a log-magnitude pre-processing block and CFAR detector for detecting radar target returns against a background.

10. The radar sub-system of claim 7, wherein said ADC buffers and said output buffers are both split memories.

11. The radar sub-system of claim 7, further comprising a substrate that provides at least a semiconductor surface, wherein said HWA is formed in said semiconductor surface.

12. The radar sub-system of claim 7, wherein said pre-processing block, said windowed FFT block and said post-processing block include independent enable (EN) circuits to provide independent muxing controls that enable/bypass for any combination of said pre-processing block, said windowed FFT block and said post-processing block.

13. A radar sub-system, comprising:

a split accelerator local memory including ADC input buffers (ADC buffers) for storing radar data sample streams, and output buffers,

a radar hardware accelerator (HWA) coupled to said ADC buffers for receiving said radar data sample streams and for processing said radar data sample streams, said HWA including;

a fast Fourier transform (FFT) engine including;

a pre-processing block for providing at least one of interference mitigation, finite impulse response (FIR) filtering and multiplying said radar data sample streams by a pre-programmed complex scalar or a specified sample from an internal look-up table (LUT) to generate pre-processed samples;

a windowing plus FFT block (windowed FFT block) for multiplying said pre-processed samples by a window vector and then processing by an FFT block for performing a FFT to generate Fourier transformed samples, and

a post-processing block for computing a magnitude of said Fourier transformed samples for generating post-processed radar data, wherein said pre-processing block, said windowed FFT block, and said post-processing block are connected in one streaming series data path, and wherein an output of said post-processing block is coupled to an input of said output buffers for transferring said post-processed radar data to said output buffers;

a parameter-set configuration memory coupled to a state machine both coupled by a bus to said FFT engine for sequencing parameters sets for execution of a chained sequence of operations and data transfers between said accelerator local memory and an external memory for controlling said pre-processing block, said windowed FFT block and said post-processing block, wherein said state machine is a parameter-set based state machine wherein said parameter-sets are programmable, said parameter-sets for configuring said HWA to perform a certain set of said operations, and wherein a sequence of executing said parameter-sets is defined; and

wherein said radar sub-system is configured to utilize 2D-memory indexing, wherein each of said parameter-sets performs a specific one of said operations on multiple ones of said radar data sample streams including a first radar data sample stream and a subsequent second radar data sample stream, and wherein a separation between subsequent samples of each of said radar data sample streams, a separation between an initial sample of said first radar data sample stream and an initial sample of said second radar data sample stream, and a number of said radar data sample streams for each of said operations is configurable via said parameter-sets.

14. A method of (FMCW) radar signal processing using a radar hardware accelerator (HWA), comprising:

coupling radar data sample streams from ADC input buffers (ADC buffers) to said HWA comprising a fast Fourier transform (FFT) engine for receiving and processing said radar data sample streams including calculating including at least one of interference-thresholding, windowing and range FFT to generate post-processed radar data including range FFT data;

streaming said post-processed radar data to output buffers;

transferring said range FFT data from said output buffers to an external memory via direct memory accesses (DMA), said DMA being triggered automatically by said HWA;

repeating said coupling, said calculating, said streaming, and said transferring for said radar data sample streams received by multiple antennas and across multiple chirps;

wherein further processing is performed on said range FFT data originating from said multiple antennas and across said multiple chirps, comprising;

transferring from said external memory in blocks to said output buffers, each said block including data for a first range gate and at least a second range gate;

performing multiple doppler FFT'"'"'s using said HWA corresponding to said first range gate, wherein said doppler FFT'"'"'s are computed for each of said multiple antennas in said first range gate;

performing an absolute value operation on result of said doppler FFT'"'"'s for each of said multiple antennas corresponding to said first range gate, and summing results of the said absolute value operation across said multiple antennas, and

repeating said further processing on subsequent data blocks from said data blocks corresponding to at least said second range gate.

15. The method of claim 14, wherein said transferring said range FFT data is performed in a transpose fashion.

16. The method of claim 14, further comprising detecting radar target returns against a background using a constant false alarm rate (CFAR) engine in a CFAR detection path parallel to a streaming series data path including a log-magnitude pre-processing block and a CFAR detector.

17. The method of claim 14, further comprising indexed memory addressing for data transfers to and from said HWA.

18. The method of claim 14, wherein said FFT engine comprises:

a pre-processing block for providing at least one of interference mitigation and multiplying said radar data sample streams within a split accelerator local memory including said output buffers by a pre-programmed complex scalar or a specified sample from an internal look-up table (LUT) to generate pre-processed samples;

a windowing plus FFT block (windowed FFT block) for multiplying said pre-processed samples by a window vector and then processing by an FFT block for performing a FFT to generate Fourier transformed samples, and

a post-processing block for computing a magnitude of said Fourier transformed samples for generating said post-processed radar data;

wherein said pre-processing block, said windowed FFT block, and said post-processing block are connected in one streaming series data path.

19. The method of claim 18, wherein said pre-processing block, said windowed FFT block and said post-processing block include independent enable (EN) circuits to provide independent muxing controls that enable/bypass for any combination of said pre-processing block, said windowed FFT block and said post-processing block.

20. The method of claim 14, further comprising 2D-memory indexing, wherein each of multiple parameter-sets performs a specific operation on multiple ones of said radar data sample streams including a first radar data sample stream and a subsequent second radar data sample stream, and wherein a separation between subsequent samples of each of said radar data sample streams, a separation between an initial sample of said first radar data sample stream and an initial sample of said second radar data sample stream, and a number of said radar data sample streams for each of said operations is configurable via said parameter-sets.