Counter-UAS systems combine four functions — detect, track, identify, and mitigate — coordinated by command-and-control software. Detection layers include RF sensors, radar, cameras, and Remote ID receivers. In Canada, detection is available to any organization; mitigation requires Transport Canada authorization under Bill C-15.
The four layers of detection
RF detection listens. Most commercial drones talk to their operators constantly — control commands up, video down. RF sensors passively detect those emissions, and advanced systems decode them: drone model, serial number, operator location, take-off point. RF is the workhorse layer, offering the widest coverage per dollar and the only detection method that produces evidence about the person flying. Its blind spot is anything that doesn't transmit: autonomous pre-programmed flights, and drones controlled through a fibre-optic tether instead of a radio link.
Radar sees. Radar transmits energy and reads reflections, which means it catches anything physically airborne whether or not it is emitting. Modern counter-drone radars are electronically scanned units tuned for small, low, slow targets, using micro-Doppler signatures — the distinct radar flicker of spinning rotors — to tell a quadcopter from a gull. Radar is the answer to the RF blind spot, and it matters more each year as autonomous and low-emission drones spread.
Cameras confirm. Electro-optical and infrared cameras, usually slewed automatically onto a radar or RF track, answer the questions the other sensors can't: what exactly is it, is it carrying anything, and can we prove it later. EO/IR is rarely the layer that finds the drone; it is the layer that turns a track into a decision and a recording into evidence.
Remote ID identifies the cooperative. Regulators increasingly require drones to broadcast identification. Remote ID receivers ingest those broadcasts cheaply, covering the large majority of traffic that is compliant and cooperative — which lets the expensive sensors concentrate on the anomalies that aren't.
Acoustic arrays — microphones matching rotor-noise signatures — fill short-range gaps in cluttered terrain, a useful niche rather than a foundation.
Why one sensor is never enough
Every layer has a failure mode, and drone builders know all of them. A drone flying a pre-programmed route emits nothing for RF to hear. A drone controlled through a thin fibre-optic tether — a technique proven at long ranges in recent conflicts — cannot be heard or jammed at all. Small airframes at low altitude challenge radar in clutter; darkness and weather challenge cameras; noise challenges microphones. Layered systems exist because the union of four imperfect sensors is far harder to defeat than any one of them, and because a track confirmed by two independent physics is a track an operator can act on.
The software that makes it a system
Sensors produce tracks; software produces understanding. The command-and-control layer fuses radar, RF, camera, and Remote ID inputs into one airspace picture, deduplicates and classifies with machine learning to suppress false alarms, maps every track against airspace and site geography, and logs an evidence-grade record of each incident. In authorized deployments it also cues the mitigation. The market's clear direction is away from standalone gadgets toward these integrated architectures — a buyer in 2026 is choosing a fusion platform first and sensors second.
Mitigation, briefly — and the Canadian line
Mitigation spans electronic methods (jamming the link, spoofing navigation, or protocol takeover — commanding the drone in its own language and landing it intact) and physical ones (interceptor drones, net capture, and, in military settings, directed energy). In Canada, all of it sits behind the Bill C-15 authorization framework: available to entities authorized by Transport Canada, unavailable to everyone else. Detection, in contrast, is deployable today.