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New sensing technologies provide smart fences with the capability to locate intrusion with accuracy of few meters.
Critical sites can be secured today by a new generation of sensors that allow detection and accurate positioning of suspected intrusions with accuracy of a few meters. This allows pointing a camera automatically to the exact intrusion point. This is the pinpoint Positioning Technology.
Magal Security Systems, a world leader in the field of perimeter security for critical sites, develops sensor technologies and delivers them to customers worldwide. The company’s products have the capability to accurately locate intruders. It should be mentioned that legacy systems were based on fence-mounted zone – sensors, typically of 100 to 200 meters long. Thus complementary means, such as observers, PTZ camera or manned patrol had to be used in order to refine the precise intrusion location. As mentioned before, the new locating sensors generation allows detection and exact positioning with accuracy of a few meters. Here is a description of the main relevant technologies:
- Copper-based microphone cable. This is a radar-like system in which an electric pulse is transmitted along the cable, while the system ’listens’ to the echo. When the fence is static, the echo is stable. However, when a specific segment of the fence is vibrated by an intrusion attempt, the echo will fluctuate. By measuring time, the system can determine the location of the intrusion. This technology enables to cover a site with up to 3km through a single power and communication feed. The system’s cost is attractive for the lion share of the market: small and medium sites (from 200m up to 5 km).
Fiber optic detector. This is an emerging technology, based on a light pulse transmission into a fiber optic cable. A fraction of light is bounced back (back-scattered) and captured by a sensitive and a sophisticated optical detector. When the fiber is static, the reflected wave is ‘calm’. However, when the optical fiber vibrates, the echo fluctuates. Very fine time measurements help in determining the distance from the processor with accuracy of a few meters. The main advantage is that a single optic fiber detector, processed by a single box, can cover a perimeter of up to 16 km. The disadvantage: is the processor is relatively expensive. However, the price is significantly amortized as the site gets bigger.
- The third method is based on tiny inertial accelerometers, installed along the fence every few meters. A communication line collects signals from the miniature vibration sensors, which are spread along the fence, and relays them to a central analyzer. Each accelerometer has excellent signal to noise performance, sensitive enough to detect low amplitude vibrations, which are typical to a rigid fence, such as the one along the Israeli-Egyptian border. Technology disadvantage: relatively complex, and also: it does not come cheap.
Hagai Katz, Senior VP Marketing and BD at Magal, explains the key advantages of the new generation of sensors:
- All detection systems should be as sensitive as possible, but without sacrificing the need for low false alarms. The new detectors have the capability of separating environmental noise (such as noise created by wind) and a local intrusion, and thus significantly improve detection performance.
- The new systems enable bolstering detection sensitivity through software – and thus compensate for the lack of uniformity in the quality of installation or the fence tension.
- Cost efficiency and savings: the new generation of detectors uses long physical detection lines, divided into virtual zones, thereby enabling the reduction of required power and communication feeds. This generates significant savings, which may be critical for remote areas with limited resources.
To summarize, all the new mentioned intrusion detector technologies provide the operational benefit of accurate intrusion location.