The Importance and Challenges of Airport Security
As vital transportation hubs with frequent flows of people and goods, airports require utmost security. Any unauthorized intrusion can seriously threaten airport operations and the safety of passengers' lives and property. Traditional airport security measures, such as the well-established human, technical, and physical defense systems within terminals, face significant challenges in perimeter areas due to their vast expanse and complex environments. For example, perimeter zones may encounter natural interferences like severe weather (rain, wind, sandstorms) and wildlife (birds, animals). Additionally, the rising use of low-altitude vehicles like drones increases the risk of illegal entry into restricted areas. These factors demand extremely high accuracy, reliability, and adaptability from airport intrusion detection systems.
Working Principles of Radar Sensors
Radar sensors are devices that use electromagnetic waves to perceive target objects. A common 24GHz radar sensor operates by transmitting microwaves at approximately 24.125GHz and receiving reflected echo signals. Its working principles mainly involve two modes:
CW Doppler Radar Sensor Mode
In this mode, the radar sensor uses 24GHz as the transmission frequency. By calculating the frequency difference between transmitted and received signals, it determines an object’s motion speed using specific formulas. A dual-channel sensor mixes the reference signal with the echo signal to output two intermediate-frequency signals (IF1 and IF2) with the same frequency amplitude but a 90° phase difference. Based on the 90° phase-guided signal type, it can accurately identify the object’s movement direction (away from or toward the radar). For instance, when an object approaches the radar, the echo signal frequency becomes higher than the transmitted frequency. Analyzing this frequency change and the phase relationship between the two intermediate-frequency signals determines the object’s motion state.
FMCW Radar Sensor Mode
To measure parameters like the distance from a static object to the sensor, a time-dependent function of linear up-chirp or down-chirp is used as the transmission frequency, with regular repetitions to obtain averages. FMCW radar generates a frequency difference between the transmitted signal and the received echo by continuously changing the transmission frequency. This frequency difference is proportional to the target’s distance. Precise measurement of the frequency difference allows calculation of the distance between the target and the radar sensor, offering high precision in distance measurement.
Advantages of Radar Sensors in Airport Intrusion Detection
All-Weather Operation Capability
Airports operate around the clock, and so must intrusion detection systems. Many traditional security devices like cameras significantly degrade in poor weather or lighting conditions. For example, heavy rain or fog severely limits a camera’s visibility, making it difficult to capture targets clearly; at night, especially in unlit areas, cameras struggle to identify potential intruders. Radar sensors, however, use electromagnetic waves and are unaffected by light or harsh weather. They can stably transmit and receive electromagnetic waves under all conditions—bright days, pitch-dark nights, heavy rain, or sandstorms—accurately detecting ground and aerial intrusions to provide continuous, reliable protection for airports.
Wide Detection Range
Airport perimeters are vast, requiring intrusion detection systems with large coverage. Radar sensors have long detection ranges; high-performance models can reach several kilometers, covering large perimeter areas and potential intrusion paths. In contrast, traditional physical perimeter sensors like vibration optical fibers or cables only protect the fence line (“line” protection), offering extremely limited coverage. Radar sensors’ wide-area detection enables “surface” protection of perimeters and surrounding areas, significantly reducing the probability of missed intrusions.
Precise Target Recognition and Tracking Capability
Radar sensors can not only detect objects but also accurately obtain information like position, speed, and movement direction. In airport environments, when an unknown object approaches or intrudes, radar sensors can monitor its trajectory in real time and maintain continuous tracking. For example, if a drone enters a no-fly zone, the radar can quickly lock its position, track its flight path, and transmit data to airport security systems. This precise target recognition and tracking allows security personnel to rapidly understand intruders’ dynamics and take effective responses, vastly improving the efficiency and accuracy of intrusion handling compared to traditional systems.
Practical Application Cases and System Construction
Muniu Technology’s Airport Perimeter Security Solution
Muniu Technology’s airport perimeter security solution based on WAYV radar has significantly enhanced safety at a domestic 4E airport. Leveraging WAYV security radar’s ability to monitor multiple targets in vast scenes, the solution accurately measures each target’s distance, azimuth, speed, and other positional information. The radar can autonomously guide PTZ (Pan/Tilt/Zoom) cameras: upon detecting an intrusion, it automatically directs cameras to zoom in and track the intruder, enabling continuous, clear capture and analysis. By networking multiple radars, it achieves seamless coverage of the entire perimeter and key areas.
System Construction and Functionality
In practice, radar sensors work in tandem with other devices in airport intrusion detection systems. Radar sensors detect and track intrusions, transmitting target information to a backend control system. The control system uses preset rules and algorithms to determine if an intrusion has occurred. Upon confirmation, it triggers alarms and coordinates with devices like cameras for verification and recording. For example, managers can view real-time intrusion positions, speeds, and trajectories via visual monitoring software. The system also integrates with third-party VMS video monitoring software or other alarm systems to enhance functionality and compatibility. Managers can define defense zones and set different alarm levels based on area sensitivity:
- Monitoring Zone (outer perimeter): Radar only activates cameras for verification, no alarm.
- Warning Zone (area near the fence): Radar triggers both cameras and alarms.
- Alarm Response Zone (perimeter line and inner airside areas): Immediate emergency alarms for detected intrusions.
This multi-layered protection ensures efficient and precise perimeter security.
Future Development Trends
With technological advancements, radar sensors in airport intrusion detection will embrace new opportunities:
1. Performance Enhancements: Improved detection accuracy, range, and reliability. New radar technologies may detect smaller targets and operate stably in more complex environments.
2. Integration with Advanced Technologies: Tighter integration with AI and big data. AI algorithms can analyze radar data in real time to improve target recognition accuracy, distinguishing natural activities (e.g., birds) from actual intrusions. Big data can analyze historical intrusion patterns to identify potential risks and inform targeted security decisions.
3. Miniaturization and Integration**: Smaller, more integrated radar systems will simplify airport deployment and reduce costs, promoting wider adoption and enhancing global airport security standards.
