TIDUEY3 November   2020

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
  7. 2System Overview
    1. 2.1 Block Diagram
      1. 2.1.1 Hardware Block Diagram
      2. 2.1.2 Software Block Diagram
        1. 2.1.2.1 mmWave SDK Software Block Diagram
        2. 2.1.2.2 Software Block Diagram of Application
    2. 2.2 Highlighted Products
      1. 2.2.1 AWR6843AOP
      2. 2.2.2 mmWave SDK
    3. 2.3 System Design Theory
      1. 2.3.1 Use-Case Geometry and Sensor Considerations
      2. 2.3.2 Low-Level Processing
      3. 2.3.3 High-Level Processing Details
        1. 2.3.3.1 DPM Model
        2. 2.3.3.2 Occupancy Detection State Machine
      4. 2.3.4 Output Through UART
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Software
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 Altium Project
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks

2.1.2.2 Software Block Diagram of Application

As shown in Figure 2-3, the implementation of the application demo on the AWR6843AOP consists of a signal chain running on the C674x DSP, and the tracking module running on the ARM®Cortex®-R4F processor.

At its core, the demo does two things:

  1. Use the radar data to produce a point cloud with each point containing a range, azimuth angle, elevation angle, and signal to noise ratio (SNR)
  2. Finds and determines seat occupancy status from the point cloud based on defined zone locations.

Processing Overview:

  • Range processing:
    • For each antenna, 1D windowing, and 1D fast Fourier transform (FFT)
    • Range processing is interleaved with the active chirp time of the frame
    • Implemented on HWA and Cortex R4F
  • Capon Beamforming (BF):
    • Static clutter removal
    • Covariance matrix generation, angle spectrum generation, and integration is performed
    • Outputs range-azimuth heat map
    • Implemented on c674 DSP
  • CFAR detection algorithm:
    • Two-pass, constant false-alarm rate
    • First pass cell averaging smallest of CFAR-CASO in the range domain, confirmed by second pass cell averaging smallest of CFAR-CASO in the angle domain, to find detection points.
    • Implemented on c674 DSP
  • Elevation Beamforming
    • Capon BF algorithm is applied again for each point detected in Range-Azimuth heatmap
    • 1-D Elevation Spectrum is generated and strongest signal is taken as the detected angle
    • Implemented on c674 DSP
  • Zone Occupancy Decision:
    • Operates on point cloud
    • Maps the point cloud to zone definition in a car
    • For each zone, based on the number of detected points and the quality of these detected point in a zone, and the previous occupancy state, a decision of occupancy state will be updated.
    • Implemented on PC as part of the visualizer
GUID-20201109-CA0I-HBFM-BFHH-HVWRN8GJQJRH-low.png Figure 2-3 Application Block Diagram