The Apstec Merlin system operates by generating a controlled magnetic field and measuring very small disturbances in that field caused by objects carried by a person. Because the system is designed to detect extremely weak magnetic signatures, it is inherently sensitive to external electromagnetic interference.
Moving electrical or electromechanical mechanisms close to the system can significantly affect its performance for several reasons:
Electric motors, actuators, elevators, escalators, automatic doors, HVAC systems, and other moving electrical equipment generate time-varying magnetic and electromagnetic fields. These fields can overlap with the operating frequency range of the magnetometry system and introduce noise that masks or distorts the signals produced by real threat objects.
Unlike static metallic structures, moving mechanisms produce changing magnetic fields. The Apstec Merlin system is particularly sensitive to such dynamic variations, as they can be interpreted as target signals, leading to:
Increased false alarm rates
Reduced detection reliability
Unstable system calibration
Electromechanical systems often introduce low-frequency vibrations and mechanical movement. These vibrations can indirectly affect sensors, cables, or structural components of the screening system, resulting in signal drift or fluctuations that degrade measurement accuracy.
Many electrical mechanisms contain ferromagnetic materials (steel shafts, motor housings, gears). When these components move, their magnetic signature changes over time, creating additional interference that cannot be easily filtered out by signal processing algorithms.
The Apstec Merlin system relies on stable environmental conditions to maintain calibration. Continuous or intermittent operation of nearby electrical mechanisms can cause baseline shifts, requiring frequent recalibration and reducing overall system availability.
One of the key installation requirements for the Apstec Merlin system is a stable, vibration-free floor. A stable floor ensures a fixed position of the system and the absence of both low-frequency and high-frequency vibrations.
⚠️ Lower Zone Performance Limitation: Floors with a rigid structural design often contain a large amount of massive ferromagnetic reinforcement elements, which create strong field interference in the lower area, particularly near the foot level.
Therefore, when using the Apstec Merlin system, it should be noted that there is always a different detection performance in the lower zone, specifically in the leg and floor-adjacent area. In practice, the detection characteristics of the system typically degrade as the target approaches the floor, due to the influence of embedded metal structures within the floor construction.