Description
Passive WiFi Radar uses ambient Wi-Fi transmissions as the illumination source and a separate receiver to measure reflections off moving targets, producing range-Doppler maps without any dedicated radar transmitter. It bridges the WiFi-sensing and radar communities: signals are commodity Wi-Fi, processing is classical radar (cross-ambiguity function, CFAR detection). Useful for evaluating CSI sensing against a radar-style baseline.
When it's used
- Range-Doppler analysis from ambient Wi-Fi traffic
- Comparison baseline for CSI sensing
- Multi-static sensing across separated TX / RX
Limitations
- Requires direct-path suppression (CLEAN, dynamic-range limits)
- Throughput / sensing trade-off depends on the underlying traffic
- Ambiguity function shape constrained by Wi-Fi waveform