TIDUF89 September   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Detection Theory
    2. 1.2 Multi-Pass Architecture
  8. 2System Overview
    1. 2.1 System Design Theory
      1. 2.1.1 Long Detection Range
        1. 2.1.1.1 Antenna Design for Long Detection Range
        2. 2.1.1.2 SNR Compensation for Long Detection Range
        3. 2.1.1.3 Smart Detection Logic
      2. 2.1.2 Low Power Consumption
        1. 2.1.2.1 Efficient Chirp Design
        2. 2.1.2.2 Deep Sleep Power Modes
        3. 2.1.2.3 Hardware Accelerator
      3. 2.1.3 Low False Alarm Rate
        1. 2.1.3.1 Typical Causes of False Alarms
        2. 2.1.3.2 False Alarms Outside the Detection Zone
        3. 2.1.3.3 False Alarms Within the Detection Zone
        4. 2.1.3.4 Adaptive State Machine
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
      1. 3.3.1 Test 1 - Detection Range
      2. 3.3.2 Test 2 - False Alarm Rate
      3. 3.3.3 Test 3 - Power Consumption
    4. 3.4 Test Results
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
  11. 5Tools and Software
  12. 6Document Support
  13. 7Support Resources
  14. 8Trademarks
  15. 9About the Authors

2.1.3.2 False Alarms Outside the Detection Zone

The FMCW encoding scheme used by the IWRL6432AOP makes sure that localization is significantly more accurate than competing technologies. Since the IWRL6432AOP can achieve nearly 4cm of range resolution, and angle accuracy within 5°, the IWRL6432AOP easily rejects false alarms that come from outside the detection zone.

60GHz radar locates targets much more accurately than competing sensing technologies. PIR sensors have no inherent ability to estimate range without prior knowledge of the target PIR sensors are detecting. To a PIR sensor, an object that emits lots of energy at a long distance looks identical to an object emitting less energy at a shorter distance. Therefore, when a large car drives by a PIR sensor at a longer distance, the PIR can confuse the car for a comparatively smaller human walking by the PIR at a shorter distance. Since the IWRL6432AOP uses FMCW radar for localization, the estimate of distance is not based off the amount of received power to the device, rather, the distance is based off the estimated frequency of the received wave to the device, which is a much more reliable indicator. See The Fundamentals of Millimeter Wave Radar Sensors, marketing white paper for more information about how radar estimates distance.

Additionally, 60GHz radar localizes to a much higher degree of accuracy than lower-frequency radars at 2.4, 5, or 24GHz. Higher frequency radars can fit more antennas in a fixed area, enabling better angular resolution, better angular accuracy, and wider fields of view. The IWRL6432AOP fits 2 TX and 3 RX antennas within a 10.9mm × 6.7mm package size. Designs of this size can be impossible at lower frequencies because the designs can require larger antennas.