1. Introduction

Since the 21st century, UAV technology has advanced rapidly and is widely applied in civilian fields such as aerial photography, logistics delivery, emergency lighting, and relay communications. However, with the rapid development of UAV technology, its applications and numbers continue to expand, posing potential safety risks—especially in civilian infrastructure, large public gatherings, and major sporting events. To mitigate these threats, counter-UAV (C-UAV) technologies have emerged. This article examines the concept and challenges of C-UAV technologies, discusses existing solutions, and provides recommendations to guide future advancements.

2. Concept and Challenges of C-UAV Technologies

2.1 Concept of C-UAV Technologies C-UAV technologies refer to methods used to detect, locate, disrupt, intercept, or destroy UAVs to safeguard public safety. Research in this field spans detection, tracking, early warning, jamming, control, capture, and neutralization techniques.

2.2 Key Challenges C-UAV operations face difficulties in detection, identification, tracking, positioning, jamming, and management:

(1) Detection Challenges

• Low, Slow, Small (LSS) UAVs: Most UAVs operate at low altitudes (<120 m), slow speeds, and with small radar cross-sections, making them hard to distinguish from ground clutter.

◦ Low Altitude: Obstructions (e.g., buildings) and ground clutter require radars with superior low-altitude coverage.

◦ Slow Speed: Traditional radars struggle with slow-moving targets; specialized low-velocity detection is needed.

◦ Small Size: High sensitivity and stability are essential to detect tiny targets.

(2) Identification Challenges

Diverse UAV designs (size, shape, speed, communication protocols) demand multi-sensor approaches (radar, infrared, optics, acoustics).

(3) Management Challenges

Distinguishing legal (e.g., authorized photography) from illegal UAVs in crowded airspace (e.g., stadiums) poses operational and legal hurdles.

3. Analysis of C-UAV Technologies

3.1 Radar Detection Modern dedicated UAV radars use electromagnetic waves to pinpoint UAVs with improved accuracy and stealth compared to traditional systems. Performance depends on UAV shape, material, and speed.

3.2 Radio Frequency (RF) Monitoring

• Tracks UAV communication signals (remote control, GPS, video transmission) to estimate location and trajectory.

• Direction-finding (single station) and time-difference-of-arrival (multi-station) techniques enhance orientation.

3.3 Electro-Optical/Infrared (EO/IR) Tracking

• Daytime: Visible-light cameras detect and track UAVs via image processing (filtering, enhancement).

• EO/IR Sensors: Monitor UAV movements using optical/thermal signatures.

3.4 Acoustic Detection

• Analyzes propeller noise against a sound signature database.

• AI-assisted matching improves identification of UAV types and activities.

• Advantage: High concealment.

4. Regulatory Measures for UAV Operations To mitigate risks, the following policies are recommended:

• Flight Rules: Define no-fly zones, altitude limits, and operational hours.

• Licensing/Registration: Mandate pilot certification and UAV registration.

• Pre-Flight Notification: Require advance notice for events/near critical infrastructure.

• Manufacturing Standards: Equip UAVs with GPS, altimeters, stabilizers, and remote IDs.

• Operator Training: Enforce safety protocols (e.g., avoiding crowds, weather compliance).

5. Conclusion

As UAVs grow smaller and smarter, their misuse for crime or disruption necessitates robust legal frameworks and multi-layered C-UAV systems. Current solutions combine soft-kill (jamming, spoofing) and hard-kill (directed energy, net-capture) tactics. This article highlights key technologies and regulatory steps to secure high-risk airspace.