With the development of society, people's security awareness has been improved and various security techniques have been widely used. In some important regions, in order to prevent illegal invasion and all kinds of sabotage activities, a combination of "human defense + physical defense" security measures have been adopted. The traditional "human defense + physical defense" measures are: Set up some barriers or barriers (such as iron fences, fences, wire fence nets, etc.) at the perimeter of these areas, and arrange personnel to step up patrols. Modern security system solutions, such as infrared point-to-point radio-to-radio schemes, electronic fences, power grids, and induction cables, have made due contributions to security, but technically limited by objective conditions, there are some such defects. Infrared point-to-point fire protection scheme has low protection level. It is easy for the intruders to discover, cross or circumvent; and the defense level of electronic fences and power grids is too high, which will cause some damage to the general intruders. unnecessary trouble. For large-scale monitoring, the power grid, sensing cables, etc., have no positioning function, and cannot determine the dangerous location in a timely and accurate manner and cannot prevent intrusion in time. It can be seen that the advanced perimeter security system must be able to identify and respond to all kinds of intrusion events in a timely manner, and must have long-distance monitoring, high-precision positioning capabilities, and should also have low energy dependence, high environmental tolerance, and electromagnetic resistance. Interference, anti-corrosion and other characteristics. Therefore, installation and application of advanced fiber perimeter detection monitoring and early warning systems have become a necessary measure.
1 Optical fiber perimeter monitoring and early warning system overview
The optical fiber perimeter detection monitoring and early warning system can integrate and integrate various traditional security protection technologies and means to form a fiber-optic sensor detection network, establish a set of modern security systems centered on photon intelligent management, and adopt high-tech photonic technologies. The means of prevention, civil air defense and physical defense, further improve the management level and work efficiency, and at the same time provide effective protection and prevention of accidents or illegal events to provide the necessary protection. Once an intruder is found, he can immediately issue an alarm, as if adding a “photon wall†that is invisible to the human eye at the perimeter of important areas.
2 Optical fiber perimeter detection monitoring and early warning system design
2.1 System Structure
The distributed optical fiber monitoring and early warning system of intelligent wired sensor network consists of master control system, industrial control computer, special alarm software, data processing and pattern recognition software, data acquisition software, printer, guided optical cable, optical cable terminal box, and sensing optical cable. . The system uses a single-core fiber optic cable as the sensing unit, and the sensitivity and identification mode of the system can be set separately on the software according to requirements. The computer will collect, analyze and process the data according to the settings.
2.2 Sensing cable laying method
At present, the distributed optical fiber monitoring and early warning system of the smart wired sensor network has two methods: the wall fixing method and the fence laying method. (1) Wall fixing method: Place the sensor cable directly on the wall and perform nailing treatment. (2) Installation of fences: Sensing optical cables are installed on perimeter fences, wire fences, and wire fences. Sensing optical cables are linearly laid on wire mesh.
2.3 Monitoring Center Design
The monitoring center has one main control system, one industrial control computer, one monitor, one printer and one sound and light alarm. When someone enters the surveillance area illegally, the distributed optical fiber vibration sensing alarm is immediately triggered. The alarm signal is transmitted to the monitoring center. The main control opportunity immediately detects and performs harmful and innocuous discrimination. If it is harmful, the alarm management computer automatically pops up the electronic map. Indicates the location of the alarm and automatically jumps out the associated video surveillance image and activates the voice alarm.
3 Fiber perimeter detection and early warning system function
The distributed optical fiber monitoring and early warning system has the following features: (1) Continuous wave and pulse wave dual mode operation mode; the system adopts continuous wave and pulse wave operation modes to synthesize the advantages of the two modes. Use OTDR technology for positioning. (2) Long-range and wide-range defense; the system's monitoring sensor is single-mode optical fiber, and the construction project is simple, using clear deposit and hanging. The optical sensor lays a circle and forms a sensory alert perimeter. (3) Accurate intrusion warning capability; the system can form a large-scale warning circle and alert circle, and any intruder approaching the fiber will generate a disturbance wave and form an alarm. (4) high sensitivity, no dead angle, no blind area, full-line sensor monitoring; system sensitivity is very high, the optical fiber is placed at the sensing position, to achieve full sensor monitoring, seamless, no dead angle, no blind area. (5) Accurate positioning of intrusive behaviors; In long-range, large-scale security systems, there is an accurate positioning of intrusion events in order to respond quickly to intrusive behavior. (6) High environmental adaptability; Corrosion conditions can be used in high and low temperature environments. The optical path has a temperature compensation function, and the temperature difference does not affect the reliability. Since the information carrier is a photon, the electromagnetic field will not affect its reliable operation, and its work will not generate electromagnetic fields and interfere with the surrounding environment. (7) Reliance on power supplies is extremely low; most of the existing security facilities are fully charged. In addition to the mainframe power supply for the all-fiber system, the sensor fiber does not use power for the entire process and relies on photons as the information carrier. (8) Sensing guard area, less maintenance, or even maintenance-free; sensor alert area, only a core fiber optic cable, no maintenance, inspection.
4 Optical fiber perimeter detection monitoring and early warning system and other security monitoring system linkage
4.1 Linkage with Video Surveillance System
Optical fiber monitoring and early warning systems and video monitoring systems use IP private network connections. The fiber optic monitoring network logs in to the video system as a client of the video system. The video system function call is completed on the client to complete the video surveillance. Once a situation occurs, the system reacts quickly on the control center display interface to indicate the location and time of the alarm. At the same time, the camera that activates the alarm area calls out the corresponding video signal display and records the scene at the time of the alarm. When the alarm occurs, the video signal at the monitoring point linked with the alarm will be automatically switched to the software interface of the fiber optic monitoring and warning system control center. The system can automatically or manually control the rotation of the pan/tilt to the alarm point position to quickly and intuitively determine the alarm condition. The stored video information can also be played back later to analyze the intrusion event.
4.2 Interaction with Infrared Systems
Infrared systems are point alarm systems. The general alarm system centralizes all alarm points to its central control unit. Infrared alarms can use perimeter alarms and can also use indoor alarms. The distributed optical fiber monitoring and early warning system of the intelligent wired sensor network has the ability to centrally manage infrared monitoring points. By collecting the infrared trigger point signal to the master control machine of the distributed optical fiber monitoring and early warning system, the two systems can be integrated together. On the one hand, the original infrared system can be independently alarmed; on the other hand, the fiber optic monitoring and early warning system can integrate infrared alarm information into the system's geographic information system to achieve centralized alarm.
5 Conclusion
The distributed optical fiber monitoring and early warning system of the intelligent wired sensor network is a brand-new security system with advanced technology, reasonable structure, and low maintenance. It can be linked with systems such as video surveillance and infrared alarms to further strengthen the security protection in key areas and effectively prevent major accidents from occurring. It provides solutions that can effectively alert external parties and objects to the perimeter in real time.
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