RU184868U1 - Wearable fragmentation explosive device detection device - Google Patents

Abstract

The utility model relates to the field of combating terrorism and can be used in the system of protecting objects. The technical result of the utility model is to increase the detection range of wearable fragmentation explosive devices. The technical result achieved is achieved by introducing a frequency tuning unit into the dual-frequency detector, connected to one of the microwave transmitters and the microwave receiver of combination frequencies. By changing the frequency of the probe signal, the nonlinear reflective properties of the search object are amplified in the form of characteristic “bursts”. In this case, its resonant properties are used, and the detection range of this object accordingly increases. 1 ill.

Description

The utility model relates to the field of combating terrorism and can be used in the system of protecting objects.

A device for non-linear radar developed in the framework of the METRA program (USA) [1]. When a metal object (fragmentation explosive device, etc.) is irradiated with a microwave electromagnetic field due to the presence of nonlinear electrical conductivity (“tunnel” effect), the third harmonic appears in the spectrum of the reflected microwave signal at the metal contacts, which is detected by the receiver.

The disadvantage of this device is the low detection efficiency due to the low signal level at the 3rd harmonic of the own harmonics of the microwave transmitter, which reduces the detection range.

Closest to the claimed utility model is a two-frequency nonlinear radar device with registration of combination frequencies in the spectrum of the reflected signal [2].

In this case, the own harmonics of microwave transmitters do not interfere with the detection process. In addition, lower received third-order combination frequencies (ƒ _pr = 2ƒ _1,2 -ƒ _2,1 ), in comparison with the 3rd harmonic, cause less shunting effect of capacities of nonlinear metal contacts of search objects, thereby increasing their reflective properties.

The disadvantage of this two-frequency device is the short detection range of metal objects, including fragmentation explosive devices.

Hidden wearable fragmentation explosive device is a metal plate, created from many contacting metal slaughter elements and located on a layer of plastid (dielectric). It is known that a metal plate has resonant reflective properties when its dimensions are comparable in magnitude with the wavelength of the microwave field incident on it [3].

The technical result of the utility model is to increase the detection range of wearable fragmentation explosive devices.

The technical result achieved is achieved by introducing a frequency tuning unit into the dual-frequency detector, connected to one of the microwave transmitters and the microwave receiver of combination frequencies. By changing the frequency of the probe signal, the nonlinear reflective properties of the search object are amplified in the form of characteristic “bursts”. In this case, its resonant properties are used and, accordingly, the detection range of this object is increased.

In FIG. 1 shows a block diagram of the proposed device.

The device for detecting wearable fragmentation explosive devices (1) contains a microwave transmitting device (2) with a stable frequency of ƒ ₁ , tunable in frequency of ƒ ₂ . A microwave transmitting device (3), a tunable frequency receiver of combination frequencies (4), as well as an introduced frequency tuning unit (5).

A device for detecting wearable fragmentation explosive devices works as follows:

The narrowly directed rays of the microwave electromagnetic field from the transmitting device (2) at a stable frequency ƒ ₁ and the transmitting device (3) tunable in frequency ƒ _{2 by the} unit (5) are emitted in the direction of the search object - fragmentation explosive device (1). The microwave electromagnetic signal reflected from the search object is received by the receiving device at the third-order combination frequency (4), which is also tuned using the frequency tuning unit (5). In this case, the frequencies of the probing and reflected signals are in the resonance region of the search object. That is, their wavelengths are comparable in magnitude with the size of this object. This leads to characteristic bursts in the amplitude of the received signal and, accordingly, to an increase in the detection range.

In order to confirm the possibility of obtaining the claimed technical result, an experiment was conducted in an anechoic chamber with dimensions (3 × 15 m). The chamber floor and its walls were covered with material (TORA-25). 6 rectangular (0.25 × 0.15 m) and one set of disk (∅0.2 m) plates from various “slaughter” metal elements (balls from ball bearings, nails, bolts, etc.) were used as mock-ups of fragmentation explosive devices. .). A simulator of explosives (plastite) was a layer of plasticine, into which slaughter metal elements were pressed. The whole structure was wrapped with tape [4].

The layout of the dual-frequency radar included microwave generators GZ-21, GCH-121 (P _a = 0.5 W), antennas P6-23A (emitting), P6-31 (receiving) and SMV-8.5 receivers. Frequency changes of the ГЧ-121 generator and the SMV-8.5 receiver were carried out manually. The frequency f _{1 of the} reference generator GZ-21 is 1300 MHz and did not change during the experiment. The frequency f _{2 of the} second generator ГЧ-121 varied discretely and amounted to 1000 MHz, 1050 MHz, 1100 MHz, 1150 MHz. Reception of the reflected signal at the 3rd combination frequency f _ap = 2f ₂ -f _l was carried out by the SMV-8.5 receiver at frequencies of 700 MHz, 800 MHz, 900 MHz, and 1000 MHz, respectively. It was established that the “bursts” in the amplitude of the received microwave signal from the search objects reached 18–25 dB, which increased their detection range by 1.7–2 times.

Information sources

1. Hager R. Harmonic Radar System. IEEE Tr V-AES 12, No. 2, 1976.

2. Scherbakov G.N. The use of nonlinear radar for remote detection of small objects. Special equipment, 1999, No. 1, p. 34-39.

3. Kobak VO. Radar reflectors. M., Soviet Radio, 1975, p. 121-124

4. M. Steinberg. The charge for the "martyr's belt" // "Russian Bazaar", No. 17 (417).

Claims (1)

A device for detecting wearable fragmentation explosive devices containing two microwave transmitters and a receiver of Raman components in the spectrum of the reflecting signal, characterized in that a frequency tuning unit is connected to it and is connected to one of the microwave transmitters and the microwave receiver of combination frequencies.

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