RU2573259C2 - Method of detecting breach of security boundary - Google Patents

Abstract

FIELD: physics, acoustics.

SUBSTANCE: invention relates to radar and hydroacoustics and can be used to form a security boundary on state and private property. The technical result is achieved by placing a transmitter at one end of the boundary, placing a receiver at the second end of the boundary, measuring the level of the received radiation and making a decision on the violation of the boundary of the secured facility when the level of the received radiation falls below a threshold value, and a decision on the violation of the boundary is also made if the level of the received radiation rises above the threshold value, i.e. the detection threshold is set for both the fall and the rise of the average radiation level at the receiving point.

EFFECT: low probability of missing a target.

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Description

The invention relates to the field of radar and sonar and can be used to create lines of protection for public and private property.

A known method of detecting violations of the border of the protected object (application No. 93038875), which consists in the fact that at one end of the border there is a microwave transmitter emitting along the border in a wide sector, at the second end of the border there is a microwave receiver that receives radiation from a microwave transmitter, measure the parameter of the received radiation and, by its value, decide on violation of the boundary of the protected object, characterized in that they measure the level of received radiation and decide on violation of the boundary of the protected object when mind shenii received radiation level is below the threshold.

A known method of detecting an object (patent No. 2296343), in which the technical result is achieved by the fact that in the method of detecting an object, including radiation in the observation zone of an electromagnetic signal reflected from the object and from the diffuser located behind the location of the object, and making a decision to detect the object carry out the reception of the signal generated at the receiving site in the form of an interference pattern, as a result of the addition of the signal reflected from the object and the signal reflected from the diffuser.

A known method of protecting water boundaries (patent No. 2364883), in which the technical result is to increase reliability, increase the sensitivity and reliability of detection, reduce the likelihood of false alarm. According to the method, a signal is generated from a hydroacoustic antenna made in the form of pieces of a piezoelectric cable, the ends of which are connected to a radio frequency cable using matching devices powered from a common source, remove the signal voltage from the load resistor and transmit it through an isolation capacitor to the input of the alarm driver, determine the parameters object according to the analysis of spectral and temporal variability of the signal.

A known method of detecting moving objects at a guarded line (application No.2010119746), which consists in analyzing the state of the electromagnetic field generated between the transmitter and the receiver, and recording changes in its amplitude under the influence of the detection object, characterized in that for detecting the intruder in a plant environment in the transmitter decimeter radiation range is used.

There is a known method and device for detecting an intruder for guarding perimeters (patent No. 2371776), where the proposed method provides equalization of the distribution of sensitivity along the boundary of protection by spatial overlapping of 90 ° phase-shifted two detection zones formed by adjacent transceivers connected from different ends of the common vibrator of the symmetric antenna . The technical result is an increase in the probability of detecting an intruder.

A known method for detecting underwater objects at the sea line in the shallow sea (patent application No. 99107404 for patent No. 2131319), in which hydroacoustic pulses directed to the upper half-space emit from a number of points with known coordinates located at the bottom on the boundary line, receive echo reflected from objects signals at the same points and the position of the object are judged by the coordinates of the receiver that detected the echo signal, characterized in that they emit pulses at neighboring points at different frequencies and at all points at the same time, take at each point, echoes of their own frequency and at least two other frequencies from adjacent emitters on each side of the line, the distance between adjacent points of reception and emission is chosen equal to twice the sea depth along the boundary line, the time of reception of echo signals is limited by the arrival time pulses reflected from the sea surface at each of the frequencies received at a given point, and the location of the detected object is specified by the coordinates of the emitters operating at the frequency of the received echo signals.

The method for detecting violations of the boundaries of the protected object (patent No. 93038875) is the closest to the claimed one and is selected as a prototype.

The aim of the present invention is to reduce the probability of missing a target (the probability of non-detection) and expanding the scope of the known method for detecting border violations (application No. 93038875), namely the use of not only microwave radio waves, but also acoustic waves (in particular, to create underwater protection borders), as well as improving the probabilistic characteristics of detection by reducing the probability of missing a target (the probability of not detecting border violations).

This goal is achieved due to the fact that in the known method, namely, that a transmitter is located at one end of the boundary, a receiver is located at the second end of the boundary, the level of received radiation is measured and a decision is made to violate the boundary of the protected object when the level of received radiation is lower than the threshold values, characterized in that the decision to violate the border is made additionally and in the case of an increase in the level of received radiation above a threshold value, i.e. the detection threshold is set both to reduce the average radiation level at the receiving point, and to increase it.

The feasibility of this technical solution can be justified theoretically in the framework of the classical theory of wave diffraction, for example, using the Huygens principle. However, omitting the theoretical calculations, as a justification for this position, we present the results of mathematical modeling of the process of crossing a flat screen of the final dimensions of the "emitter-receiver" path at different distances from the source as shown in Fig. 1, where and, n is the radiation source and receiver, respectively, t1, t2, t3 are the paths of movement of the screen. The emitter-receiver distance is 20 m. A 0.5 m × 0.2 m screen crosses the source-receiver line at a right angle at a distance h from the source emitting the signal, whose wavelength is λ = 6 cm.

The signal at the receiving point is generated by the direct signal of the radiation source and the signal of the source, reflected at the boundary of the screen.

In fig. Figure 2 shows the diffraction pattern (envelope of the signal at the receiver), observed when the screen intersects the acoustic path created by the emitter and the receiver at a distance of 15 m, 17 m and 19 m from the emitter, respectively.

It can be seen that in the process of moving the screen in one of the three cases there is a decrease in the signal level, and in two - its increase. Therefore, if the threshold is set only to reduce the signal level, the detection of an object at the protection line will occur in only one of three cases. If the threshold is set to both decrease and increase the level, then detection will occur in all three cases.

Information sources

application No. 93038875;

patent No. 2296343;

patent No. 2364883;

application No.2010119746;

patent No. 2371776;

Patent No. 2161319.

Claims (1)

A method for detecting a violation of the border of a protected object, which consists in the fact that a transmitter emitting along the border in a wide sector is located at one end of the border, a receiver receiving radiation from the transmitter is located at the second end of the border, the received radiation parameter is measured, and a border violation decision is made from its value protected object, characterized in that they measure the level of received acoustic radiation and decide on violation of the boundary of the protected object both when decreasing, and when increasing the level of received acoustic radiation below or above predetermined threshold values, each of which is set both to reduce the average level of acoustic radiation at the receiving point, and to increase it, respectively.

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