RU2507505C1 - Method of detecting and identifying explosives and narcotic drugs and apparatus for realising said method - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: apparatus which carries out the disclosed method includes a transceiving antenna, an antenna switch, a transmitter, a receiver, first and second high frequency amplifiers, an analogue-to-digital converter, a measuring means, a memory unit, a display unit, the inspected object, a processor, a comparator unit, a switch, first and second multipliers, first and second low-pass filters, first and second optimal controllers, first and second 26 controlled delay units, first and second correlators, a range indicator 19 and an azimuth indicator.

EFFECT: broadening functional capabilities of existing engineering solutions by locating an inspected object where an explosive or narcotic drug has been detected.

2 cl, 1 dwg

Description

The proposed method and device relate to techniques for the detection of explosive and narcotic substances, in particular to methods and devices for detecting explosive and narcotic substances in various closed volumes and on the body of a person located in crowded places.

Known methods and devices for the detection and identification of explosives and narcotic substances (ed. Certificate of the USSR No. 1.131.138, 1.800.333; RF patents No. 2.086.963, 2.150.105, 2.161.300, 2.179.716, 2.185.614 , 2.226.686, 2.283.485, 2.436.073; U.S. Patent Nos. 4,529.710, 4,599.740, 4.651.085, 4.756.866, 5.668.734, 6.507.278; U.K. Patent No. 1,033.452 and others) .

Of the known methods for the detection and identification of explosive and narcotic substances, the closest to the proposed one is the "Method for the detection and identification of explosives" (RF patent No. 2.283.485, G01N 22/00, 2004), which is selected as a prototype.

The known method is based on the fact that the reference values of the phase shifts corresponding to the dielectric properties of the inclusions of certain types of explosive and narcotic substances are preliminarily recorded in the memory of the measuring means, the controlled object is irradiated with a pulsed microwave signal with preset values of the carrier frequency of the probe pulses, of duration and amplitude in the frequency range from 300 MHz to 150 GHz with a duration of probing pulses not exceeding 10 ms, measure the magnitude of the phase shift pr of the detected signal relative to the emitted and its intensity, the value of which determines the absorption coefficient of the controlled object, compare the measured phase shift of the received signal relative to the radiated with the reference values, after which the presence of an explosive or narcotic substance and its type of.

However, the known technical solutions do not provide the ability to determine the location of the controlled object in which an explosive or narcotic substance is detected.

An object of the invention is to expand the functionality of known technical solutions by determining the location of a controlled object, on which an explosive or narcotic substance is detected.

, где R - расстояние до контролируемого объекта, на котором обнаружено взрывчатое или наркотическое вещество, с - скорость распространения радиоволн, поддерживают указанное равенство, что соответствует максимальному значению первой корреляционной функции R₁(τ), и определяют расстояние R до контролируемого объекта, на котором обнаружено взрывчатое или наркотическое вещество, одновременно перемножают отраженный сигнал, принятый приемной антенной, разнесенной в горизонтальной плоскости на расстояние d, где d - измерительная база, с отраженным сигналом, принятым приемопередающей антенной и пропущенным через второй блок регулируемой задержки, выделяют низкочастотное напряжение, пропорциональное второй корреляционной функции R₂(τ), изменяют время задержки τ до наступления равенства τ=τ_з2, где τ_з2=t₁-t₂, где t₁, t₂ - время прохождения отраженными сигналами расстояний от контролируемого объекта, на котором обнаружено взрывчатое или наркотическое вещество, до приемопередающей и приемной антенн соответственно, поддерживают указанное равенство, что соответствует максимальному значению второй корреляционной функции R₂(t), и определяют азимут на контролируемый объект, на котором обнаружено взрывчатое или наркотическое веществоThe problem is solved in that a method for detecting and identifying explosive and narcotic substances, including, in accordance with the closest analogue, irradiating the controlled object with a pulsed microwave signal with specified values of the carrier frequency of the probe pulses, their duration and amplitude, receiving a signal reflected from the controlled object, amplification and analog-to-digital conversion of the received signal, measuring the values of the parameters of the converted signal and comparing them with the reference values of the measuring medium In this case, the reference values of the phase shifts corresponding to the dielectric properties of the inclusions of certain types of explosives and narcotic substances are preliminarily recorded in the memory of the measuring means, the controlled object is irradiated in the frequency range from 300 MHz to 150 GHz with a probe pulse duration not exceeding 10 ms, measured the magnitude of the phase shift of the received signal relative to the radiated and its intensity, the value of which determines the absorption coefficient of the controlled object, compare the measured value of the phase shift of the received signal relative to the radiated with the reference values, after which, based on the results of the comparison, taking into account a certain absorption coefficient of the controlled object, the presence of an explosive or narcotic substance and its type is different from the closest analogue in that after detecting an explosive or narcotic substance at the controlled object, the reflected signal received by the transceiver antenna is multiplied with the probing signal passed through a first adjustable delay block, allocate a low-frequency voltage proportional to the first correlation function R ₁ (τ), where τ - current time delay, changing a time delay τ to the equality of _P1 τ = τ where τ = _Z1 $$\frac{2R}{c}$$

where R is the distance to the controlled object at which an explosive or narcotic substance is detected, c is the propagation speed of radio waves, the indicated equality is maintained, which corresponds to the maximum value of the first correlation function R ₁ (τ), and the distance R to the controlled object at which an explosive or narcotic substance is detected, at the same time multiply the reflected signal received by the receiving antenna, spaced horizontally at a distance d, where d is the measuring base, with reflected with the second signal received by the transceiver antenna and passed through the second block of adjustable delay, a low-frequency voltage is proportional to the second correlation function R ₂ (τ), the delay time τ is changed until the equality τ = τ _z2 , where τ _z2 = t ₁ -t ₂ , where t ₁ , t ₂ is the time taken by the reflected signals to travel from the controlled object where the explosive or narcotic substance was detected to the transceiver and receiver antennas, respectively, support this equality, which corresponds to the maximum the value of the second correlation function R ₂ (t), and determine the azimuth to the controlled object, which detected explosive or narcotic substance

. $$\beta =\arccos \frac{c}{d}{\tau }_s{}_2$$

.

The problem is solved in that a device for the detection and identification of explosive and narcotic substances, containing, in accordance with the closest analogue, a series-connected transmitter, an antenna switch, the input-output of which is connected to a transceiver antenna, a first high-frequency amplifier, an analog-to-digital converter, a processor, the input-output of which is connected to the transmitter, a comparison unit, the second input of which is connected to the output of the memory unit, and an indication unit, differs from the closest analogue in that it equipped with a key, two multipliers, two low-pass filters, two extreme regulators, two adjustable delay units, a range indicator, a receiving antenna, a second high-frequency amplifier and an azimuth indicator, with a key connected to the output of the first high-frequency amplifier, the second input of which is connected to the output of the comparison unit, the first multiplier, the second input of which is connected to the output of the transmitter through the first adjustable delay unit, the first low-pass filter and the first a belt regulator, the output of which is connected to the second input of the first adjustable delay unit, the range indicator is connected to the second output, the second high-frequency amplifier, the second multiplier, the second input of which is connected to the key output through the second adjustable delay unit, are connected to the output of the receiving antenna a low-pass filter and a second extreme regulator, the output of which is connected to the second input of the second block of adjustable delay, to the second output of which an indicator is connected azimuth.

The structural diagram of a device that implements the proposed method is presented in the drawing.

The device contains a series-connected transmitter 3, an antenna switch 2, the input-output of which is connected to a transceiver antenna 1, a first high-frequency amplifier 5, an analog-to-digital converter 6, a processor 11, the input-output of which is connected to a transmitter 3, a comparison unit 12, and a second the input of which is connected to the output of the memory unit 8, and the indication unit 9. To the output of the first high-frequency amplifier 5, a key 13 is connected in series, the second input of which is connected to the output of the comparison unit 12, the first multiplier 15, the second input of which is connected to the output of the transmitter 3 through the first adjustable delay unit 18, the first low-pass filter 16 and the first extreme regulator 17, the output of which is connected to the second input of the first adjustable delay unit 18, to the second output of which a range indicator 19 is connected. A second high-frequency amplifier 21, a second multiplier 23, the second input of which through the second adjustable delay unit 26 is connected to the output of the key 13, the second low-pass filter 24 and the second extreme regulator 25, the output of which is connected to the second input of the second block 26 adjustable delay, the second output of which is connected to the indicator 27 of the azimuth.

The first high-frequency amplifier 5 and the analog-to-digital converter form the receiver 4. The processor 11, the comparison unit 12, and the memory unit 8 form the measuring means 7. The first multiplier 15, the first low-pass filter 16, the first extreme regulator 17 and the first adjustable delay unit 18 form the first correlator 14. The second multiplier 23, the second low-pass filter 24, the second adjustable delay unit 26 form a second correlator 22. The device also contains a controlled object 10.

The method of detection and identification of explosives and narcotic substances is as follows.

The monitored object 10 to be checked for the presence of explosive or narcotic substances is irradiated with weak high-frequency electromagnetic radiation. A microwave signal in the frequency range from 300 MHz to 150 GHz with a duration not exceeding 10 ms is generated in the transmitter 3. To irradiate the controlled object 10, a pulsed microwave signal can be generated in the form of a sequence of bursts of pulses. In this case, for each burst of pulses its own value of the carrier frequency is set, and the value of the carrier frequency for the subsequent burst of pulses is either increased or decreased. The microwave signal generated in the transmitter 3 with the given parameters through the antenna switch 2 enters the antenna 1 and is emitted in the direction of the monitored object 10. Since the power of the emitted (probing) microwave signal is small, passengers or people can be directly tested for explosives or drugs located in places of mass events.

The reflected signals from the controlled object 10:

u ₁ (t) = U ₁ · Cos [w _c (t-τ _з1 ) + φ ₁ ],

u ₂ (t) = U ₂ · Cos [w _c (t-τ _з2 ) + φ ₂ ], 0 <t≤T _c ,

- время задержки отраженного сигнала относительно зондирующего;where τ ₃ 1 = $$\frac{2R}{c}$$

- delay time of the reflected signal relative to the probing;

τ _s2 = t ₁ -t ₂ , t ₁ , t ₂ - the time the signal travels distances from the controlled object 10 to the transceiver antenna 1 and the receiving antenna 20;

R is the distance from the transceiver antenna 1 to the controlled

object 10;

C is the propagation velocity of radio waves.

The reflected signal u ₁ (t) is received by the antenna 1 and enters through the antenna switch 2 to the input of the receiver 4, in which it is amplified by a high-frequency amplifier 5 and converted using an analog-to-digital converter 6 into a form convenient for its further processing in the measuring means 7 performed, for example, using a processor 11, which allows digital processing of the received signal with the determination of its phase shift relative to the probing and intensity, followed by comparison in block 12 solutions with reference values recorded in block 8 of the memory. If there are dielectric inclusions on the controlled object 10 (in particular, on the human body), the parameters of the received signal will differ from the parameters of the received signal reflected from the controlled object that does not contain explosive or narcotic substances. The differences will be a change in the phase of the received signal and its intensity. The phase change will be different for different dielectrics. By comparing the phase of the received signal with the reference values of the phase shifts recorded in the memory unit 8, corresponding to the dielectric properties of the inclusions of certain types of explosive and narcotic substances, an explosive or narcotic substance can be identified. The obtained data can be displayed on the display in block 9 of the display. In the simplest case, an indicator lamp can be used, the inclusion of which indicates the detection of explosive or narcotic substances.

When an explosive or narcotic substance is detected at the controlled object 10, a constant voltage is generated at the output of the comparison unit 12, which is supplied to the control input of the key 13, opening it. In the initial state, the key 13 is always closed. In this case, the reflected signal u ₁ (t) from the output of the high-frequency amplifier 5 through the public key 13 is fed to the first input of the first multiplier 15 and to the first input of the second adjustable delay unit 26.

A probe signal is supplied to the second input of the first multiplier 15 from the output of the transmitter 3 through the first adjustable delay unit 18

u _c (t) = U _c · Cos [w _c (t-τ _з2 ) + φ ₂ ], 0≤t≤T _c ,

where τ is the variable delay introduced by the first adjustable delay unit 18.

The voltage obtained at the output of the multiplier 15 is passed through a low-pass filter 16, at the output of which a low-frequency voltage is generated, which is proportional to the first correlation function R ₁ (τ). The extreme controller 17, designed to maintain the maximum value of the first correlation function R ₁ (τ) and connected to the output of the low-pass filter 16, acts on the control input of the first adjustable delay unit 18 and maintains the delay τ introduced by it equal to τ _s1 (τ = τ _s1 ) , which corresponds to the maximum value of the first correlation function R ₁ (x). The range indicator 19, associated with the scale of the adjustable delay unit 18, allows you to directly read the measured value of the distance R to the controlled object 10 on which an explosive or narcotic substance is detected,

. $$R=\frac{c{\tau }_{s\mathrm{one}}}{2}$$

.

The reflected signal u ₂ (t) from the output of the receiving antenna 20 through the high-frequency amplifier 21 is fed to the first input of the second multiplier 23, to the second input of which the reflected signal u ₁ (t) is supplied from the output of the first high-frequency amplifier 5 through the second adjustable delay unit 26 through the public key 13. In this case, the scale of the second adjustable delay unit 26 (azimuth indicator 27) is calibrated directly to the angular coordinates of the controlled object 10 on which an explosive or narcotic substance is detected

, $$\beta =\arccos \frac{c}{d}{\tau }_s{}_2$$

,

where d is the distance between the transceiver 1 and the receiving 20 antennas (measuring base);

τ _z2 = t ₁ -t ₂ , t ₁ , t ₂ - the transit time of the reflected signals of the distances from the controlled object to the transceiver 1 and the receiving 20 antennas, respectively.

Explosive and narcotic substances can also be detected if the controlled object is a multilayer structure (for example, an explosive or narcotic substance under human clothing), since the reference values previously recorded in the memory unit 8, with which the values of the parameters of the received signals are compared, represent is a set of parameter values of received signals from various objects (including those with a multilayer structure), with explosive or narcotic things present in them stvami, ie from objects that will be close in their characteristics to the objects to be inspected containing explosive or narcotic substances. Usually a computer model is used to simulate any multilayer structure.

A device that implements the proposed method can be performed with three antennas, one of which serves to emit a signal, and the other two to receive reflected signals.

When a controlled object with a multilayer structure is irradiated, multiple reflections occur. The multilayer structure can be irradiated with a sequence of monochromatic packets containing at least 100 wavelengths. In this case, the passage of waves through a multilayer structure can be considered periodic. The result is obtained by solving the one-dimensional Helmholtz equation (M. Born, E. Wolf. Fundamentals of optics. M., Nauka, 1974, p. 72). The solution for each wave packet depends on the distance to the layered structure, the thickness of the layers and their electrophysical properties, and the distance to the layered structure can be easily determined by the parameters of the received signal (by the time of its delay relative to the emitted). The total number of unknowns is 3N + 1, where N is the number of layers. By measuring the phase and amplitude of the received signal for each wave packet, it is easy to solve the corresponding system of equations if 2M≥3N + 1, where M is the number of wave packets.

Solving this system, we obtain the values of conductivity, permittivity and thickness of each layer. This gives us the opportunity to determine if there are dangerous substances in the specified layered structure.

Thus, the proposed method and device, in comparison with the prototype and other technical solutions, provide not only reliable detection and identification of explosive and narcotic substances, but also allow you to accurately and unambiguously determine the direction of the controlled object, which detected explosive or narcotic substance, and range to its location. In this case, an increase in the direction finding accuracy of the controlled object is achieved by increasing the measuring base d, and the ambiguity that arises in this case is eliminated by correlation processing of the reflected signals. Thus, the functionality of the method and device is expanded.

Claims (2)

1. A method for detecting and identifying explosive and narcotic substances, including irradiating a controlled object with a pulsed microwave signal with specified values of the carrier frequency of the probe pulses, their duration and amplitude, receiving the signal reflected from the controlled object, amplifying and analog-to-digital conversion of the received signal, measuring values the parameters of the converted signal and comparing them with the reference values of the measuring means, while previously in the memory of the measuring means of recording reference values of phase shifts corresponding to the dielectric properties of inclusions of certain types of explosives and drugs are irradiated, the controlled object is irradiated in the frequency range from 300 MHz to 150 GHz with a probe pulse duration not exceeding 10 ms, the magnitude of the phase shift of the received signal relative to the emitted and intensity, by the value of which the absorption coefficient of the controlled object is determined, the measured value of the phase shift of the received signal is compared relatively emitted with reference values, after which the presence of an explosive or narcotic substance and its type, which is characterized in that after detecting an explosive or narcotic substance at a controlled object, multiply the reflected signal received by the transceiver antenna, are determined using a probing signal passed through the first block of adjustable delay, emit a low-frequency voltage proportional to howl correlation function R ₁ (τ), where τ - current time delay, changing a time delay τ to the equality of _P1 τ = _τ, where $${\text{τ}}_{\text{s1}}=\frac{\text{2R}}{\text{c}}$$

where R is the distance to the controlled object at which an explosive or narcotic substance is detected, c is the propagation speed of radio waves, the indicated equality is maintained, which corresponds to the maximum value of the first correlation function R ₁ (τ), and the distance R to the controlled object at which an explosive or narcotic substance is detected, at the same time multiply the reflected signal received by the receiving antenna, spaced horizontally at a distance d, where d is the measuring base, with reflected with the second signal received by the transceiver antenna and passed through the second block of adjustable delay, a low-frequency voltage is proportional to the second correlation function R ₂ (τ), the delay time τ is changed until the equality τ = τ _z2 , where τ _z2 = t ₁ -t ₂ , where t ₁ , t ₂ is the time taken by the reflected signals to travel from the controlled object where the explosive or narcotic substance was detected to the transceiver and receiver antennas, respectively, support this equality, which corresponds to the maximum the value of the second correlation function R ₂ (τ), and determine the azimuth to the controlled object, which detected explosive or narcotic substance,
$$\beta =\arccos \frac{c}{d}{\tau }_s{}_2$$

. 2. A device for detecting and identifying explosive and narcotic substances, comprising a series-connected transmitter, an antenna switch, the input-output of which is connected to a transceiver antenna, a first high-frequency amplifier, an analog-to-digital converter, a processor, the input-output of which is connected to a transmitter, a unit comparison, the second input of which is connected to the output of the memory unit, and an indication unit, characterized in that it is equipped with a key, two multipliers, two low-pass filters, two extreme controllers, two adjustable delay units, a range indicator, a receiving antenna, a second high-frequency amplifier and an azimuth indicator, and a key is connected to the output of the first high-frequency amplifier, the second input of which is connected to the output of the comparison unit, the first multiplier, the second input of which is through the first block adjustable delay connected to the output of the transmitter, the first low-pass filter and the first extreme regulator, the output of which is connected to the second input of the first block of adjustable rear the arm, to the second output of which a range indicator is connected, a second high-frequency amplifier, a second multiplier, a second input of which is connected to the key output through a second adjustable delay unit, a second low-pass filter and a second extreme regulator whose output is connected to the output of the receiving antenna the second input of the second adjustable delay unit, the second output of which is connected to the azimuth indicator.