The perimeter protection system detects attempted access to a protected object at the first boundary of protection that is on the perimeter. Thus, perimeter protection the equipment is the most effective means of protecting against unauthorized access since issues an alarm signal (with more or less precise indication of the place of infringement)long time before the attacker can penetrate into the especially important areas of the protected object.
The perimeter protection systems take a separate place in the spectrum of security systems. The task of the perimeter protection, as a rule, allocated in a separate technical problem. First of all it is necessary to define with the term “perimeter”. Perimeter in our case can be considered as boundary of the protected territory of the object, unauthorized overcome which should cause alarm with a more or less precise indication of the place of infringement..
Features of system design perimeter protection due to the fact that the protected territory usually has a large length, and security detectors overlap large areas (30 to 500 meters per detector). Sensors are installed on various designs, and at installation demand carrying out significant construction works. Technical means of perimeter protection work all year that must be considered when selecting equipment.
The effectiveness of the perimeter protection system can be repeatedly increase and simultaneously reduce the costs of its operation, if coupled with the perimeter protection system to install a video surveillance system. The mechanical obstacles (walls, fences) complicate and delay the penetration of the violator on protected territory, alarm system will help in short time to detect a violator and a video surveillance system will allow to exclude the false alarm and to see the real cause of it.
At a choice of perimeter protection systems it is necessary to consider a number of factors:
- Understanding of the potential violator. It should be clearly understood from what and from whom you want to protect your territory. Selection of the optimal perimeter protection systems directly depends on who is a potential troublemaker: a professional saboteur, a random drunk passers-by or local resident, who came on your territory searching of "bad laying" of nonferrous metals.
- Understanding of the possible ways of overcoming the protected border. How the violator can penetrate into your territory? To climb over the fence? To break the barrier? Make a tunnel?
- Construction features of the passive barrier. What mechanical obstacles stand in the way of the violator? Concrete fence? Netting? Wooden fence? Reinforced barbed tape? Or mechanical obstacles are non-existent?
- The existence of track side. Many detectors require the indispensable presence of free space outside or inside of the protected space.
- The natural and seasonal phenomena. The height of the snow cover in winter can reach 2-3 meters, which will undoubtedly impact on the security detector. In summer should take into account the active growth of grass, shrubs and trees.
- The location of roads and railway lines. Highways and Railways are a source of strong interference and can seriously affect the correct operation of the sensor. Passports for perimeter detectors, as a rule, always specify the acceptable distance to the highway or railroad tracks.
- The number and types of discontinuities (gate). Linear (continuous) sections of the perimeter is protected by other means than the gate. For gates and other deficiencies in the mechanical barrier, it is necessary to install another type of detectors.
- Masking and aesthetics. If for military objects a major requirement is the "invisibility" of security sensors, but for civil structures (for example, cottage villages), it is essential to the aesthetic appearance of the detector. In addition, masking allows to increase the probability of detecting violator since by external signs will be difficult to determine the presence of alarm in the protected area.
- Additional factors: relief features, the topography of the object types of the surrounding vegetation, the presence near the perimeter of the power lines, pipelines, cable lines, wildlife migration, etc.
1. Capacitive perimeter protection system.
Capacitive perimeter protection system consists of a conductor system which have a specific container relative to the ground. When touched the fence, or approaching it their container changes and an alarm is generated
2. Vibration perimeter protection system.
The main element of the perimeter protection system is a special sensor cable. The advantage of this system is that it can be used as on the fences of the nets and in the concrete structures.
3. Infrared perimeter protection system.
Infrared systems are divided into two types: active and passive. Active perimeter systems is a transmitter that emits multiple linear invisible rays and the transceiver. With the loss of one or more such rays alarm sounds.
4. Radio wave perimeter protection system.
Operating principle radio wave systems, is based on registration of disturbances of an electromagnetic field, which causes a entering into this field violator.
5. Radio beam perimeter protection system.
Radio beam perimeter security systems consist of a transmitter and a transceiver, between which creates an electromagnetic field of elliptical shape.
6. Vibration-sensitive systems.
These devices operate on the basis of registrations of some mechanical vibration or deformation of envelope structures. In this case, as the sensing element is a special sensor cable. It transforms the mechanical vibrations into electric signal.
7. Optical sensors with scanning function.
The most advanced are the optical analogues. The sensor can be positioned so that its scanning plane is parallel to the wall.
8. Wireless sensors.
When the cabling is impossible or complicated by a number of factors, used the special wireless sensors. They are powered by an autonomous source, and signal transfer is carried out by the radio alarm.
9. Monostatic sensors.
As an alternative, for the realization of protection of some perimeter areas using passive infrared sensors.
10. Radio beam devices.
With the help of the radar beam is formed in the detection area in the form of an ellipsoid. Restrictions, which are relevant for radiation sensors are take place to be.