Introduction to Counter-Unmanned Aircraft Systems (C-UAS) Counter-Unmanned Aircraft Systems (C-UAS) are integrated technical systems used to detect, identify, track, disrupt, capture, or destroy unmanned aerial vehicles (UAVs).

With the widespread application of UAVs in both civilian and military fields, their potential threats—such as privacy invasion, intrusion into sensitive areas, and terrorist attacks—have driven the rapid development of counter-UAV technologies.

This paper systematically introduces C-UAS from three aspects: core technical categories, application scenarios, and challenges & trends. I. Core Technical Categories C-UAS technologies mainly consist of two major stages: detection & identification and countermeasure & neutralization. 1. Detection and Identification Technologies - Radar Detection Suitable for medium-to-long-range detection and tracking high-speed targets. However, traditional radars have low recognition rates for low, slow, small (LSS) targets (e.g., plastic-body UAVs). New-generation phased-array radars and millimeter-wave radars improve detection accuracy. - Radio Frequency (RF) Spectrum Detection Detects UAVs by monitoring communication signals between UAVs and remote controllers (e.g., Wi-Fi, video transmission signals), enabling identification of UAV models and operator positions. Ineffective against UAVs in silent flight (pre-programmed routes). - Electro-Optical Identification (Visible/Infrared) Uses cameras and thermal imagers for visual recognition, combined with AI algorithms to classify targets (e.g., distinguishing birds from UAVs). Limited by weather conditions and field of view. - Acoustic Detection Identifies unique sound signatures of UAV rotors via microphone arrays, suitable for complex urban environments, but with a short effective range (typically < 500 meters). - Multi-Sensor Integrated Detection Systems Fuses data from multiple sensors (e.g., radar + electro-optics + RF), enhancing detection accuracy and anti-jamming capability through multi-source information fusion. 2. Countermeasure and Neutralization Technologies - Radio Jamming Emits high-power jamming signals to block communication links between UAVs and operators (remote control, GPS/Beidou navigation), forcing UAVs to hover, return-to-home, or make an emergency landing. Common frequency bands include 2.4 GHz, 5.8 GHz, and GNSS bands. - Navigation Spoofing Sends false GPS signals to mislead UAVs into flying to safe areas or deviating from routes. Technically demanding but highly covert. - Laser Weapons High-energy laser beams instantly burn key UAV components, suitable for military scenarios. Requires high precision in tracking moving targets and has high energy consumption. - High-Power Microwave (HPM) Weapons Emits high-power microwaves to destroy UAV electronic circuits, enabling area-effect neutralization, but may cause collateral damage to nearby equipment. - Physical Interception - Net Interception: Launches net projectiles or uses carrier UAVs with capture nets, suitable for urban environments sensitive to collateral damage. - Kamikaze Interceptor UAVs: Use high-speed UAVs to directly collide with targets. - Missiles/Artillery: Deployed by militaries against large or swarm UAV threats. - Cyber Hacking Technologies Intrudes into UAV control systems to seize control or inject malicious commands. Requires cracking communication protocols, technically difficult but extremely covert. II. Application Scenarios - Military and Border Defense Protect military bases and critical facilities from reconnaissance or attacks, e.g., vehicle-mounted C-UAS widely used in the Russia-Ukraine conflict. - Critical Infrastructure Protection Safeguard sensitive areas such as nuclear power plants, airports, and power grids. For example, airport C-UAS prevent disruptions to flight operations. - Security for Major Events Prevent UAV disturbances or terrorist attacks during sports events, political summits, and other large-scale activities. - Privacy and Commercial Security Prevent UAV voyeurism, smuggling (e.g., in prison areas), and industrial espionage. - Expanded Civilian Applications Used for no-fly zone management in wildlife reserves and airspace order maintenance for UAV logistics.