No single drone detection technology is sufficient on its own. RF, radar, acoustic and optronic layers each have their own strengths and constraints: understanding them is what makes it possible to build a coherent protection system, rather than relying on a single layer.
RF detection relies on intercepting an exploitable radio link between a drone and its operator. Radar emits a signal and analyses its echo to detect a physical object. Optronic and thermal systems observe a scene visually. Acoustic detection passively listens to the surrounding sound environment.
None of these approaches covers every scenario on its own: each is most effective under certain conditions, and each has conditions under which its observation signal weakens.
| Criterion | RF | Radar | Acoustic | Optical / thermal |
|---|---|---|---|---|
| Requires an exploitable RF emission | Yes | No | No | No |
| Passive by nature | Passive (radio listening) | Active (emits a signal) | Passive | Passive |
| Localisation capability | Direction of the radio source | Precise distance and direction | Azimuth via multi-sensor triangulation | Visual direction, within the camera's field of view |
| Main environmental constraints | Radio interference, jamming | Terrain masking, clutter | Ambient noise, wind | Weather, lighting, line of sight |
| Dependence on visual conditions (day/night/weather) | None | None | None | High (thermal: reduced) |
| Sensitivity to a site's ambient noise | Not applicable | Not applicable | Yes, reduced range in noisy environments | Not applicable |
| Fibre-optic (wired) drone link | RF signal reduced or absent, depending on architecture | Remains operational: detects the physical object | Remains operational: detects the drone's noise | Remains operational if the drone is within view |
RF systems rely on the presence of an exploitable radio emission. When a device does not produce one (a preprogrammed autonomous flight) or when its link is not radio-based (fibre-optic piloting), this detection layer can lose part of its observation signal.
Radar, optical, thermal and acoustic sensing then remain other possible means of observation: the drone is still a physical object in motion, producing a radar-exploitable echo, a thermal signature, an image within a camera's field of view, and a characteristic mechanical noise. Each of these channels has its own operating conditions, but none depends on a radio emission from the drone.
EKHO is not intended to replace radar, RF or optronic systems. Acoustic sensing adds a further detection layer, independent from the others and passive by nature, in a sensor-fusion logic: combining several observation sources to reduce the combined blind spot of a protection system, rather than relying on a single technology.
The principle of acoustic detection, explained in detail.
Learn more about acoustic drone detection →