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

2.3.1 Use-Case Geometry and Sensor Considerations

The AWR6843AOP is a radar-based sensor that integrate a fast FMCW radar front end with both an integrated ARM R4F MCU and the TI C674x DSP for advanced signal processing. The key performance parameters of the system are influenced by the configuration of the transmit signal and the RF transceiver, the design of the antenna array, and the available memory and processing power.

The key performance parameters at issue follow with brief descriptions:

  • Maximum Range - maximum range at which a human can be detected
  • Range Resolution - minimum distance require between two objects for the radar to detect them as separate objects
  • Maximum Velocity - the maximum unambiguous velocity that can be detected. Objects moving faster than this may have incorrect velocity measurements
  • Velocity resolution - minimum velocity difference between two objects for the radar to detect them as separate objects

When designing the frame and chirp configuration for a vehicle occupancy detection use case, start by considering increasing range resolution and velocity resolution over maximum range and velocity; because objects are within short range, defined zones will be relatively stationary. Table 2-1 lists example chirp configurations with good range and Doppler resolution and memory for a incabin sensing application.

Table 2-1 Performance Parameters of Example Chirp Design
KEY INPUT PARAMETERS
Starting frequency (GHz) 60
Maximum range, Rmax (m) 2.72
Range resolution (cm) 5.3
Maximum velocity (m/s) 1.7
Velocity resolution (m/s) 0.0154
Idle time (µs) 205
ADC valid start time (µs) 11
Periodicity (ms) 200
Valid sweep bandwidth (MHz) 2822
Ramp slope (MHz/µs) 97
Sampling frequency (Msps) 2.2
Number of samples per chirp 64
Ramp end time (µs) 41
Number of chirp loops 220
Active frame time (ms) 162