PortolanBearings Network · FreeRF Sensing
Sensor TechnologyRF sensing passively detects and classifies emitters by listening to the electromagnetic spectrum rather than transmitting.
RF sensing (also called passive RF, ELINT, or SIGINT at the operational scale) detects the presence, direction, and identity of emitters by receiving their radio-frequency signatures. Unlike radar, an RF sensor emits nothing — making it stealthy and complementary to active systems in contested environments. In counter-UAS applications, RF sensors identify a drone's control link and video downlink before radar or optical systems achieve custody. RF sensing is central to electronic-support (ES) missions, spectrum management, and the passive layer of layered air defense. The industrial base includes DRS, L3Harris, RTX's ES subsidiaries, and a growing tail of counter-UAS specialists.