Design

Counter-drone protection for critical facilities: designing layered defence

Counter-drone systems are often selected from a catalogue. A year later it turns out the radar faces a wall, the optics cannot see a low-flying target, and the operator has no authority to press the button. Design starts with the site, not the hardware.

October 7, 202610 minArchitecture

Contents

Threat model: what exactly are you protecting?3D model and zones Three layers in height Five project steps Application circuit Four remedies and when to use them Collateral damage and legal framework How to measure effectiveness

Each object has its own geometry, its own interference and its own rules. A plant with a tank farm, an airport with civil traffic and a substation in an urban area require different sensors, different means and different rules of application. Therefore, the project begins with a survey, and not with the selection of the “longest-range” radar.

Threat model: what exactly are you protecting?

The threat model does not describe “drones in general,” but specific scenarios: type of device, altitude and flight speed, probable launch points, flight time, presence of optical-electronic payload and warhead. For one object, a reconnaissance quadcopter is critical, for another - an FPV drone with a shaped charge, for a third - a loitering dive munition.

Not only the composition of the system, but also the rules of application depend on the threat model: where can an electronic radar be used, where can a laser be used, and where is kinetic interception the only acceptable response?

3D model and zones

A three-dimensional model is superimposed on the object: relief, buildings, pipes, tanks, power lines, tree crowns. For each point, line of sight, radar background and electromagnetic environment are calculated. This is how zones appear where the radar sees the target, and zones where it will never see it.

The practical result is not a map of “beautiful sectors”, but a list of blind spots and a solution: to close them with a second position, distributed by OES or acoustics. It is at this stage that it most often turns out that one position cannot cover the entire perimeter.

Three layers in height

Echelon	Height	Typical threats	Means
Above the building line	100–1000 m	Loitering munitions, FPV, reconnaissance	Radar, long-range OES, electronic radar, interceptor, laser
Below the building line	20–100 m	Commercial quadcopters, short-range reconnaissance	OES search, compact complexes, RTR
Under the canopies	5–20 m	Microdrones, fiber optic devices	Distributed OES, acoustics, near suppression

Five project steps

Threat model Types of targets, attack scenarios, probable launch points, acceptable reaction time.
3D examinationObject geometry, blind spots, radar and electromagnetic background.
Sensor coverage. Arrangement of radar, EOS, RTR and acoustics with checking of overlaps.
Selection of means. REP, laser suppression, laser destruction, interception - for each zone and rule.
Rules and training Who decides which areas are closed, how use is recorded.

Application circuit

Detection, confirmation, evaluation, impact and outcome verification are the five steps the system goes through for each goal. The time for each step is set by the project. In the AEROTEGIS configuration, the cycle from detection to targeting is less than five seconds, but operator participation is configurable at each stage.

A system that does not record its actions cannot be accepted for balance. The application log is part of the architecture, not an optional extra.

Four remedies and when to use them

Means	Range	Effect	When to use
RAP	up to 5 km	Control and navigation channel suppression	First line, if there is no risk to your connection
Interceptor drone	up to 3 km	Kinetic defeat	The target continues to approach, debris is acceptable
Laser suppression	up to 2 km	Optical glare	Reconnaissance drone, must be forced to leave
Laser defeat	up to 1.5 km	Glider destruction	Last line, line of sight, minimal damage

Collateral damage and legal framework

Every remedy has its limits. RF jamming can interfere with one's own communication and navigation; laser requires safety zones; interception creates falling debris. The project must contain zone tables, frequency windows, calculated fall trajectories and application approval procedures.

For a critical object, this is not bureaucracy, but a condition of exploitation. A system that cannot be used without additional approval will remain disabled in a real alarm.

How to measure effectiveness

Probability of detection for a given ESR and weather.
Number of false alarms per day.
Time from detection to impact.
The cost of one interception, taking into account the resource of funds.
System availability and recovery time after failure.
Completeness of the log and the ability to analyze operator actions.

Where does the project begin?

From a threat model and 3D inspection of the object. Equipment is selected after zones, blind spots and acceptable reaction times are determined.

Is it possible to start with one position and expand the system?

Yes. An architecture with edge computing nodes allows you to add sensors and tools without rebuilding the control loop.

Who decides on application?

The rules are set by the project. In automatic mode, the system operates according to pre-approved scenarios; manually - the operator confirms each impact.

What to do with the debris?

For kinetic interception, impact zones are calculated. For laser destruction, debris is also taken into account, but their scattering is less than when the warhead is detonated.