Constant False Alarm Rate (CFAR) is an adaptive thresholding technique used in radar signal processing to detect targets by dynamically adjusting the detection threshold relative to the local noise or clutter level, ensuring a statistically consistent false alarm probability across varying environmental conditions. In Wi-Fi and passive radar sensing contexts, CFAR is applied to range-Doppler maps or similar time-frequency representations to distinguish meaningful human motion signatures from background noise and interference, making it essential for robust, environment-independent activity detection. Common variants include Cell-Averaging CFAR (CA-CFAR), which estimates noise power by averaging surrounding range or Doppler cells, and ordered-statistic CFAR (OS-CFAR), which is more resilient to multiple closely spaced targets or non-homogeneous clutter environments.
Source Papers
- An Overview on IEEE 802.11bf: WLAN Sensing ↗ — An Overview on IEEE 802.11bf: WLAN Sensing
- MMCOUNT: Stationary Crowd Counting System Based on Commodity Millimeter-Wave Radar ↗ — MMCOUNT: Stationary Crowd Counting System Based on Commodity
- On CSI and Passive Wi-Fi Radar for Opportunistic Physical Activity Recognition ↗ — On CSI and Passive Wi-Fi Radar for Opportunistic Physical Ac
- Passive WiFi Radar for Human Sensing Using a Stand-Alone Access Point ↗ — Passive WiFi Radar for Human Sensing Using a Stand-Alone Acc