II. In-Depth Analysis of Key Technical Principles of Counter-Unmanned Aerial Vehicle (C-UAV) Equipment

1. Specific Implementation of Signal Jamming

The core principle is "suppressive jamming." The system directs high-power jamming signal energy towards the target direction using a directional antenna. At the UAV's receiver, the jamming signal combines with the genuine control signal, severely degrading the signal-to-noise ratio (S/N). The effective signal becomes drowned in noise, leading to communication link disruption. Modern advanced jamming systems possess multi-mode switching capabilities, allowing flexible selection between barrage, targeted, and spoofing modes based on the scenario to balance effectiveness and collateral impact.

2. Working Principle of GPS/GNSS Spoofing

Taking generative spoofing as an example, the process is a precise "pull-and-capture" sequence:

· Signal Generation: Based on the intended target geographic location (Point C), the spoofing device calculates in real-time the parameters—such as pseudo-random code phase, carrier Doppler shift, and navigation message data—that should be received from all visible satellites at that point.
· Signal Transmission: The spoofing device radiates these forged GPS signals into the airspace via its antenna, with a power level slightly higher than that of the genuine signals.
· Pull and Capture: The UAV's GPS receiver initially acquires the genuine signals. Due to their slightly higher power, the spoofing signals create a stronger "correlation peak." The spoofing device then fine-tunes the parameters of its forged signals, causing this "spoofing correlation peak" to move slowly. This gradually pulls the receiver's tracking loops away from the "genuine correlation peak" and attracts them to the spoofing signal, eventually causing the receiver to lock completely onto the spoofing signal.
· Complete Control: Once the receiver is locked onto the spoofing signal, the calculated position, velocity, and time information are entirely controlled by the spoofing signal. The attacker can then arbitrarily "guide" the UAV to any specified location.

3. Mechanism of Spectrum Monitoring and Identification

This technology is a form of passive detection, with its core being feature recognition and localization.

· Feature Recognition: The communication protocols and video transmission signals between a UAV remote controller and the UAV possess unique spectral characteristics (such as specific modulation methods, bandwidth, frequency hopping patterns, etc.). Spectrum monitoring systems contain extensive databases of UAV radio frequency (RF) fingerprints. By comparing received signals against this database in real-time, the system can identify UAV signals and determine their model, even within complex electromagnetic environments.
· Localization:
  · Single-Site Direction Finding: Uses a directional antenna or antenna array to determine the signal's azimuth (direction of arrival) and roughly estimates distance combined with the Received Signal Strength Indicator (RSSI).
  · Time Difference of Arrival (TDOA): Multiple receiver stations are deployed across an area. By measuring the minute time differences of the target UAV's signal arriving at these different stations, the system can precisely calculate the UAV's three-dimensional coordinates.

III. Typical Practical Application Cases

C-UAV equipment has been successfully deployed in various critical domains worldwide:

· Airport Security: Numerous airports domestically and internationally have deployed C-UAV systems. For instance, after Shanghai Pudong International Airport deployed a system in 2025, it successfully forced multiple intruding UAVs to land via signal jamming, effectively averting risks of flight operation disruptions.
· Security for Major Events: During large international events, summits, etc., C-UAV systems form a core component of aerial security, used to prevent terrorism, unauthorized filming, disruption of order, and other malicious acts utilizing UAVs.
· Protection of Critical Infrastructure: C-UAV equipment is widely used in sensitive areas such as military bases, nuclear power plants, government compounds, and prisons. Case studies show that a Public Security Bureau and detention center in Fujian Province effectively thwarted attempts to use UAVs for delivering contraband into the facility by deploying such a system.
· Military and Defense Applications: This represents the cutting edge of technology application. The most famous case is the successful capture of a US RQ-170 "Sentinel" stealth UAV by Iran in 2011 through GPS spoofing technology. Furthermore, in border conflicts and for military base protection, portable jamming guns and fixed jamming stations have become standard equipment for individual soldiers and point defense.
· Addressing Rogue Flights and Illegal Activities: Law enforcement agencies use C-UAV equipment to deal with UAV "rogue flights" that disrupt civil aviation, invade privacy for unauthorized filming, engage in smuggling, drug trafficking, and other illegal activities, with significant results.

IV. Challenges and Development Trends

1. Current Challenges:

· Adaptability in Complex Environments: Urban multipath effects (signal reflections from buildings) and complex electromagnetic environments pose challenges to the accuracy of detection and jamming.
· Swarm Tactics: Countering low-cost UAV swarm attacks is an extremely difficult problem.
· Regulations and Collateral Interference: High-power jamming can potentially affect surrounding legitimate radio equipment, and its use is subject to strict legal and regulatory restrictions.
· Jamming-Resistant UAVs: Advanced UAVs are beginning to incorporate anti-jamming technologies such as frequency hopping, encrypted communications, and visual navigation, placing higher demands on C-UAV systems.

2. Future Trends:

· Intelligence and Automation: Utilizing Artificial Intelligence (AI) to achieve automatic target recognition, threat level assessment, and response decision-making.
· Multi-Technology Fusion: Deep integration of data from various detection methods—such as radar, RF, electro-optics, and acoustics—to enhance system reliability and anti-jamming capability in complex environments.
· Practical Application of Directed Energy Weapons: Laser and microwave weapons are developing towards smaller size, higher efficiency, and lower cost, poised to become key solutions for countering swarm attacks.
· Collaborative Countermeasures: Developing decentralized, distributed networks of C-UAV systems that operate cooperatively to address regional UAV threats.

In summary, C-UAV equipment is a complex system integrating advanced radar, radio frequency, optical, acoustic, and artificial intelligence technologies. Its principle does not rely on a single technology but involves the flexible selection or combination of multiple methods—ranging from "soft" jamming and spoofing to "hard" kinetic destruction—based on the threat level and application scenario, forming a multi-layered UAV defense system.

---

Post time:Sep-25-2020