Definition and principle of perimeter prevention

The direct meaning of the perimeter is the outermost collection of the area. The definition of perimeter defense (system) should be: the defense formed along the perimeter. The purpose of establishing perimeter precautions is to form a safe area: to ensure that people, property, etc. in the area are under protection and control, and to restrict the behavior of entering (exiting) this area; once a target enters through the prohibited section (Out) When it is in a safe area, it can detect and find the exact location of the event in time; record the process of the above event; implement a limited warning or strike on the target if necessary. Among the above-mentioned links, judging whether the target is invaded is the first and most critical link in the whole process. The correctness of the response in this link determines the effectiveness of all subsequent links.

At present, perimeter defense systems all use detection of changes in physical media to achieve intrusion detection. The main physical quantities involved in the application are: infrared (active infrared intrusion detector), microwave (shielded microwave intrusion detector), laser (blocking laser intrusion detection Device, optical fiber safety protection network), electrostatic field (electret microphone cable), electromagnetic field (leakage cable, induction cable), mechanical force (tensile electronic cable), etc.

The above basically lists the categories of existing perimeter intrusion detectors, from which it can be found that the above-mentioned intrusion detection technologies are all achieved by measuring the change of a single physical quantity, but the information contained in the entire incident of intruder invasion is by no means Any one of the above single physical quantities can correspond. At present, the detection results of all intrusion detectors cannot be completely accurate, that is, it is inevitable that intrusion detectors produce false alarms and missed alarms! Based on this most basic understanding, we can correctly set up or understand the evaluation criteria of the detector.