What Detection Technologies Does the Sensor Use (Radar, Infrared, Loop Replacement, Laser), and How Accurate Is It?

Modern automatic doors, parking barrier gates, and access control systems rely heavily on sensor accuracy to ensure safety, efficiency, and reliability. To meet different application requirements, today’s sensors integrate multiple detection technologies, including radar, infrared, loop replacement, and laser sensing. Each technology has its own strengths, detection principles, and accuracy levels.

This article explains how these detection technologies work and how accurate they are in real-world applications.

1. Radar Detection Technology

How It Works

Radar sensors typically use microwave Doppler or FMCW (Frequency-Modulated Continuous Wave) technology to detect motion by emitting microwave signals and analyzing reflected waves. Changes in frequency indicate movement toward or away from the sensor.

Key Advantages

Reliable detection of moving vehicles and pedestrians

Strong resistance to dust, rain, fog, and low-light conditions

Suitable for outdoor environments and high-traffic areas

Detection Accuracy

Vehicle detection accuracy: >99% in standard parking and gate applications

Adjustable sensitivity and detection zones reduce false triggering

Less effective for stationary objects unless combined with other technologies

Typical Applications

Parking barrier gates

Industrial and commercial automatic doors

Vehicle access control systems

2. Infrared Detection Technology

How It Works

Infrared sensors use active infrared beams or reflected infrared light to detect the presence of objects within a defined area. When the infrared signal is interrupted or reflected differently, the sensor triggers a response.

Key Advantages

Precise short-range detection

Fast response time

Effective for pedestrian presence detection

Detection Accuracy

Presence detection accuracy: 98–99% within calibrated range

Performance can be affected by strong sunlight, heavy rain, or reflective surface

Accuracy improves significantly when combined with radar or laser technology

Typical Applications

Automatic sliding and swing doors

Safety sensors for pedestrian zones

Indoor access control systems

3. Loop Replacement Technology

How It Works

Loop replacement sensors replicate the function of traditional inductive ground loops without the need for cutting pavement. They typically rely on radar, magneto-resistive, or combined sensing technologies to detect metal mass and vehicle presence.

Key Advantages

No ground cutting or civil work required

Lower installation and maintenance costs

Easy retrofitting for existing parking systems

Detection Accuracy

Vehicle presence detection accuracy: >99%

Stable performance across different vehicle sizes

Advanced algorithms minimize interference from nearby moving objects

Typical Applications

Parking barrier gates

Toll stations

Access control retrofits

4. Laser Detection Technology

How It Works

Laser sensors emit high-precision laser beams and measure the time-of-flight or reflection angle to detect objects and calculate distance. This allows for highly accurate area and contour detection.

Key Advantages

Extremely precise detection zones

Excellent for safety-critical applications

Can distinguish between people, vehicles, and background objects

Detection Accuracy

Detection precision: millimeter-level accuracy

Reliable even in complex environments

Advanced filtering reduces false triggers from rain, dust, or sunlight

Typical Applications

Safety curtains for industrial and high-speed doors

Anti-pinch protection systems

High-security entrances and logistics facilities

5. Combining Technologies for Maximum Accuracy

Modern sensors often integrate multiple detection technologies—such as radar + infrared or radar + laser—to leverage the strengths of each method. This hybrid approach provides:

Higher overall detection accuracy

Reduced false triggering

Improved performance in challenging environments

In combined systems, overall detection reliability can exceed 99.5%, making them suitable for demanding commercial, industrial, and transportation applications.

Conclusion

Radar, infrared, loop replacement, and laser detection technologies each play a crucial role in modern sensor solutions. While radar excels in motion detection and environmental resilience, infrared provides precise presence sensing, loop replacement offers cost-effective vehicle detection, and laser technology delivers unmatched accuracy and safety performance.

By selecting the appropriate detection technology—or a combination of technologies—system integrators and facility operators can ensure optimal accuracy, safety, and long-term reliability for automatic doors, parking barrier gates, and access control systems.