Experimental and numerical investigation of interception effectiveness for UAV FCN countermeasures

Abstract Aiming at the threats posed by unmanned aerial vehicles (UAVs) to critical infrastructure and the limitations of existing defense systems, this study investigated the interception effectiveness of flexible anti-UAV capture net (FCN) countermeasures. An FCN system with an octagonal structure, consisting of Kevlar fiber mesh ropes and explosive formed projectile (EFP) warheads, was designed. An interception effectiveness evaluation model applicable to both point and area targets was established based on the Monte Carlo algorithm, which incorporated the nonlinear dynamic characteristics of the net and the six-degree-of-freedom trajectory equations of UAVs for analysis. The results showed that in point target protection, traditional passive protection required a C40 concrete layer thickness of 2.62 m at a vertical impact velocity of 300 m/s, while a circular deployment of 4 flexible nets with a 10 m spacing achieved an interception rate exceeding 90%. For area target protection, the radius of the C40 concrete layer in traditional passive protection needed to exceed the structural radius by 8.64 m at a 51.3° incidence angle. When the deployment density of flexible nets was 0.0085 units/m2, the interception rate reached 90%, and 1.5 times the number of interception units compared to the number of targets was required to counter swarms. This technology had significant advantages in improving survival probability and reducing costs, providing a basis for optimizing the ‘passive-active’ collaborative defense.