Ukraine’s Logika design bureau has developed an automated engineering barrier called Chagarnik, or Kustarnik, designed to counter FPV drones controlled through fiber-optic cables. The system is intended to detect an approaching UAV, identify the threat and physically sever the communication line linking the drone to its operator.

The complex combines acoustic sensors with a moving metal cable deployed around a protected position. Its detection system listens for the sound produced by drone motors and propellers. Artificial intelligence analyzes the acoustic signature and determines the direction from which the FPV drone is approaching.

Once a target is detected, the mechanical barrier is activated automatically. A closed-loop metal cable fitted with special hooks is mounted on supports surrounding the position. An electric drive then sends the cable moving rapidly around the perimeter in a continuous cycle.

The system exploits a defining feature of fiber-optic FPV drones. During flight, the UAV trails a thin cable that carries video and control signals between the aircraft and its operator. If the fiber reaches the moving cable of the Chagarnik system, the hooks are designed to catch it, while the resulting tension and mechanical force tear the line apart.

Once the fiber-optic connection is severed, the operator loses both the video feed and control of the drone. The UAV then loses guidance before reaching the protected position, according to Voennoye Obozreniye.

Chagarnik has also been designed to work with the Kropiva combat software used by the Ukrainian Armed Forces. When the system detects a drone, an alert is transmitted to tablets used by nearby units, giving them additional warning about the incoming aerial threat.

The barrier can be configured for different defensive tasks. According to the developers, it can protect a single trench or be extended across a larger area to form a continuous defensive line along a selected direction.

In practical terms, Chagarnik functions as an automated mechanical trap for fiber-optic control lines. Its sensors detect the approaching FPV drone, after which the moving barrier attempts to hook and break the cable trailing behind it.