RU2433423C1 - Subsurface probing device - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: subsurface probing device has a synchroniser 1, a transmitter 2, an antenna switch 3, an antenna system 4 with transceiving and receiving antennae, a first low-noise amplifier 5, a first detector 6, a first digital time interval measuring device 7, a first squaring device 8, a first adder 9, a first multiplier 10, a second adder 11, a divider 12, a third adder 13, a second squaring device 14, a fourth adder 15, a square-root extractor 16 and a display unit 17, a second low-noise amplifier 18, a second detector 19, a second digital time interval measuring device 20, a fifth adder 21, a third squaring device 22, a second multiplier 23, a frequency halver 24 and a data input unit 25.

EFFECT: high accuracy of determining coordinates of a point target during subsurface probing.

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Description

The invention relates to radio engineering, mainly to radar objects, and, in particular, can be used for subsurface sounding of internal organs and structures of humans and animals in the process of ultrasound studies.

The well-known "subsurface sounding radar", comprising an antenna connected to an antenna switch, which is connected to the output of the transmitter and the input of the high-frequency unit of the receiver, connected through an intermediate frequency amplifier with a coordinate transformer, at the output of which the display is on; range selection unit with n-inputs, each of the n-inputs of which is connected to the output of the intermediate frequency amplifier and to one of the inputs of the n-multipliers, the other input of each of which is connected to the output of the strobe generator, each of the n-outputs of the block range selection through the input of the Doppler filtering unit is connected to one of m Doppler filters, the output of each of which is connected to its integrator detector, the outputs of which are connected to the coordinate converter (Certificate for Utility Model of the Russian Federation No. 22826, publ. 27. 04.2002).

A disadvantage of the known radar is the low accuracy of determining the coordinates of a point target.

A device for radar sensing of the subsurface space is known, comprising a transmitting antenna with a transmitter of a probe pulse, a receiving antenna with an amplifier of pulses reflected from subsurface objects and an analog-to-digital converter of the input signal associated with it. The transmitter was launched controlled simultaneously with the receiver turned on, and the transmitting and receiving antennas were shielded in the frequency range from 5 MHz to 1 GHz in the form of several layers of radio-absorbing pile material with the ohmic resistance of the layer closest to the antenna equal to the wave resistance of the free space 377 Ohms , and with a gradual decrease in resistance according to the exponential law from the inner layer to the outer, the analog-to-digital converter is configured to directly rabotki input signal from a frequency range of 5 MHz to 1 GHz output signal with the display on a logarithmic scale amplitude (Patent Utility Model RF №81812, publ. 27.03.2009).

The disadvantage of this device is the inability to measure the coordinates of the subsurface point target.

Closest to the proposed technical solution is a device for remote sensing of subsurface layers of the soil, used to solve electrical prospecting using side-scan radars installed on board aircraft, to increase the resolution in depth by processing the reflected ultra-wideband signals in the phase plane using the generalized frequency method. The device comprises an antenna system (hereinafter, an antenna system with a transmitting and receiving antennas), a radiation pattern scanning unit, an antenna switch, a transmitter, a high frequency unit (hereinafter referred to as a low noise amplifier), a delay line, a limiter amplifier, a first detector, a trigger, an attenuator, a second detector, an intermediate frequency amplifier, a third detector, an indicator unit, a synchronizer, a fast sawtooth generator, a comparator, a strobe pulse generator, a stroboscopic mixer, an expander and pulses, low-pass filter, brightness modulator amplifier, slow sawtooth voltage generator, frequency divider (hereinafter referred to as a frequency divider by two), cathode ray indicator, horizontal scan generator, first and second differentiating blocks, first, second and third quadrators, normalizing block, the first and second multipliers, the first and second adders, the first and second blocks of square root extraction and the voltage divider (RF Patent No. 2154845, publ. 08/20/2000).

The disadvantages of the known device (hereinafter, subsurface sensing devices) include low measurement accuracy, which is caused by counting the coordinates of a point target in a two-dimensional image of a subsurface spatio-temporal signal on the screen of an electron beam indicator, as well as the impossibility of its use in subsurface sounding of internal organs of humans and animals in the process of ultrasound.

The basis of the invention is the task of increasing the accuracy of determining the coordinates of a point target in subsurface sounding and, in particular, in ultrasound examinations of internal organs and structures of humans and animals.

The problem is solved in that the subsurface sensing device, comprising an antenna system with a transmitter-receiver and receiver antennas, an antenna switch, a transmitter, a first low-noise amplifier, first and second detectors, an indicator unit, a synchronizer, a frequency divider into two, first, second and third the quadrators, the first and second multipliers, the first and second adders and the square root extraction unit, according to the invention further comprises a data input unit, a third, fourth and fifth adders, a divider, there is a low-noise amplifier, first and second digital meters for the duration of time intervals, moreover, a transmitter, an antenna switch and an antenna system with a transmitter-receiver and receiver antennas are connected in series to the second output of the antenna switch, a first low-noise amplifier, a first detector, and a first digital time interval meter, first quadrator, first adder, first multiplier, second adder, divider, third adder, second quad OP, the fourth adder, the square root extraction unit and the indicator unit, which is connected to the output of the divider by the second input, between the output of the antenna system with the transceiver and receiver antennas and the fourth adder, a second low-noise amplifier, a second detector, and a second digital time interval meter are connected in series , the fifth adder, the third quadrator and the second multiplier, the output of the transmitter is connected to the second inputs of the first and second digital meters of the duration of the time interval, the output with the synchronizer is connected to the third input of the second digital meter of the duration of the time interval and to the input of the frequency divider by two, the output of which is connected to the third input of the first digital meter of the duration of the time interval, whose output is connected to the second input of the fifth adder, the output of the third quadrator is connected to the second input of the first adder and the data input unit is connected by its outputs to the second inputs of the third adder, divider, second adder and the first and second multipliers, respectively.

Figure 1 shows the structural diagram of a device of subsurface sounding. Figure 2 shows the geometry of subsurface sounding when a point target is located in the space under study.

The subsurface sensing device comprises a synchronizer 1, connected in series with the transmitter 2, the antenna switch 3 and the antenna system 4 with the transmit-receive and receive antennas. The first low-noise amplifier 5, the first detector 6, the first digital meter 7 of the time interval, the first quadrator 8, the first adder 9, the first multiplier 10, the second adder 11, the divider 12, the third adder 13, the second quadrator are connected in series to the second output of the antenna switch 3 14, the fourth adder 15, the square root extraction unit 16 and the indicator unit 17, which is connected by a second input to the output of the divider 12. To the output of the antenna system 4 with the transmit-receive and receive antennas are connected the second low-noise amplifier 18, the second detector 19, the second digital meter 20 of the time interval, the fifth adder 21, the third quadrator 22 and the second multiplier 23, the output of which is connected to the second input of the fourth adder 15. The output of the transmitter 2 is connected to the second inputs of the first and second digital meters 7 and 20 of the duration of the time interval. The output of the synchronizer 1 is also connected to the third input of the second digital meter 20 for the duration of the time interval and to the input of the frequency divider 24 into two, the output of which is connected to the third input of the first digital meter 7 for the duration of the time interval, whose output is also connected to the second input of the fifth adder 21. Output the third quadrator 22 is also connected to the second input of the first adder 9. The data input unit 25 is connected by its outputs to the second inputs of the third adder 13, divider 12, second adder 11 and first, respectively and the second multipliers 10 and 23.

The device operates as follows. The synchronizer 1 generates an infinite sequence of short electrical pulses following with a quantization frequency f _sq. These pulses trigger the transmitter 2, in which the frequency f _kv decreases to the frequency of the probe pulses, which, through the antenna switch 3, drive the transmit-receive antenna of the antenna system 4. At the same time, the first 7 and second 20 digital meters of the duration of the time interval are started .

The probe signal is emitted by the transmitting and receiving antenna of the system 4 into the investigated subsurface space (for example, into the studied region of the human or animal body during ultrasound studies). The reception of the signal reflected by the point target is carried out by the transmitting and receiving antennas of the antenna system 4.

Let the transceiver antenna of the antenna system 4 is located on the surface of the investigated subsurface space at the point X _0, and the receiving antenna at the point X ₁ (figure 2). The point target is located in the investigated subsurface space and has the coordinates Z _a (depth) and X _a . As follows from geometric constructions, the target is located at the intersection of two circles - the first centered at a point X ₀ and radius t ₀ * V and the second centered at a point X ₁ and radius t ₁ * V, where V is the signal propagation velocity in the subsurface space, t ₀ is the transit time of the probe signal from point X ₀ to the point target, t ₁ is the travel time of the reflected signal from the point target to the receive point X ₁ .

Antenna switch 3 provides switching of the probing (radiated) and received signals in the receive-transmit mode in order to decouple a sufficiently powerful sounding signal from the output of the transmitter 2 from the input of the first low-noise amplifier 5.

The received-transmitting antenna of the antenna system 4, the signal reflected by the target through the antenna switch 3 is fed to the input of the first low-noise amplifier 5, where it is amplified and fed to the first detector 6, where the envelope of this signal is extracted. Next, the signal from the output of the first detector 6 is fed to the first input of the first digital meter 7 of the duration of the time interval, which stops the counting of quantizing pulses by its counter. Since the duration of the time interval measured in node 7 is formed as a result of the pulse passing a double distance to the target, to obtain the value of t _0, it is necessary to apply the quantization frequency 7 of the duration of the time interval to the quantization frequency f _sq / 2. To do this, the quantizing frequency from the output of the synchronizer 1 is fed to the third input of the first digital meter through a frequency divider 24 into two.

Received by the receiving antenna of the antenna system 4, the signal reflected by the target after amplification in the second low-noise amplifier 18 is supplied to the second detector 19, where the envelope of this signal is extracted. Next, the signal from the output of the second detector 19 is fed to the first input of the second digital meter 20 of the duration of the time interval, which stops the counting of quantizing pulses by its counter. The quantization of the second digital meter 20 of the duration of the time interval is carried out on the third input with a frequency of f _square from the output of the synchronizer 1. Digital meters of the duration of the time intervals are widely known and quite deeply described (for example, in the book Digital Phasometry. - Radio and Communication, 1993, author M.K. .Hmyh).

The measured value of t ₀ in the form of the number N ₀ from the output of the first digital meter 7 of the duration of the time interval is fed to the second input of the fifth adder 21 and to the input of the first quadrator 8, from the output of which the value N ₀ ² goes to the first input of the first adder 9.

The measured value t ₀ + t ₁ in the form of the number N from the output of the second digital meter 20 of the duration of the time interval is supplied to the first input of the fifth adder 21, where N ₀ is subtracted from it. From the output of the fifth adder 21, the number N ₁ = NN ₀ enters the input of the third quadrator 22, from the output of which the value N ₁ ² enters the second input of the first adder 9 and the first input of the second multiplier 23.

In the first adder 9, the operation subtracts N ₁ ² from

N ₀ ^{2. The} number equal to N ₀ ² -N ₁ ² from the output of the first adder 9 goes to the first input of the first multiplier 10, the second input of which receives the constant V ² from the first output of the data input unit 25, which is also fed to the second input the second multiplier 23, where the operation of multiplying the number N ₁ ² by the constant V ^{2 is} performed. In the first multiplier 10, the operation of multiplying the number N ₀ ² -N ₁ ² by the constant V ^{2 is} carried out. From the output of the first multiplier 10, the value of V ² (N ₀ ² -N ₁ ² ) goes to the first input of the second adder 11, the second input of which from the second output of the data input unit 25 receives the constant X ₁ ² -X ₀ ² . In the second adder 11, the numbers V ² (N ₀ ² -N ₁ ² ) and X ₁ ² -X ₀ ^{2 are} added. Next, the value of V ² (N ₀ ² -N ₁ ² ) + X ₁ ² -X ₀ from the output of the second adder 11 goes to the first input of the divider 12, the second input of which receives the constant 2 (X ₁ -X ₀ ) from the third output of the block 25 data entry. In the divisor 12, the number received at its first input is divided by the number received at its second input. The number X _a from the output of the divider 12 is supplied to the second input of the indicator unit 17 and to the first input of the third adder 13, the second input of which receives the constant X ₁ from the fourth output of the data input unit 25. In the third adder, the operation subtracts the number X ₁ from the number received at its first input. The value of X _a -X ₁ from the output of the third adder 13 is fed to the input of the second quadrator 14, where the operation of taking the number into the square is performed. Then the value (X _a -X ₁ ) ² from the second quadrator 14 is fed to the first input of the fourth adder 15, the second input of which receives the number from the output of the second multiplier 23. In the fourth adder 15, the number received at its first input is subtracted from the number, received at his second entrance. The value of (Vt ₁ ) ² - (X _a -X ₁ ) ² from the output of the fourth adder 15 is supplied to the square root extraction unit 16, where the square root extraction operation takes place. The number Z _a from the output of block 16 extract the square root is fed to the first input of the indicator block 17.

Thus, it can be shown that the coordinates X _a and Z _a are calculated by the formulas

,

,

,

moreover, to calculate Z _a only the positive value of the root is used.

On the indicator unit 17 displays the numerical values of the coordinates of the point target Z _a and X _a accurate to the accuracy of the computational operations.

The coordinate is counted from the point of origin, which, for example, can be a transmit-receive antenna of the antenna system 4.

Thus, the proposed device in comparison with the prototype provides an increase in the accuracy of determining the coordinates of a point target in subsurface sounding and, in particular, in ultrasound studies of internal organs and structures of humans and animals.

Claims (1)

A subsurface sensing device including an antenna system with a transmitting and receiving antennas, an antenna switch, a transmitter, a first low-noise amplifier, first and second detectors, an indicator unit, a synchronizer, a frequency divider into two, first, second and third quadrants, the first and second multipliers, the first and a second adders and a square root extraction unit, characterized in that it further comprises a data input unit, a third, fourth and fifth adders, a divider, a second low-noise amplifier, the first and there are digital measuring instruments for the duration of time intervals, with a transmitter, an antenna switch and an antenna system with a transmitting and receiving antennas connected in series to the synchronizer output, a first low-noise amplifier, a first detector, a first digital measuring instrument for the duration of a time interval, a first quadrator, connected in series to a second output of the antenna switch first adder, first multiplier, second adder, divider, third adder, second quad, fourth adder, extraction unit the square root and the indicator unit, which is connected to the output of the divider by the second input, between the output of the antenna system with the transceiver and receiver antennas and the fourth adder, a second low-noise amplifier, a second detector, a second digital time interval meter, a fifth adder, a third quadrator and a second multiplier are connected in series , the transmitter output is connected to the second inputs of the first and second digital time interval meters, the synchronizer output is connected to the third input the second digital meter of the duration of the time interval and with the input of the frequency divider into two, the output of which is connected to the third input of the first digital meter of the duration of the time interval, whose output is connected to the second input of the fifth adder, the output of the third quadrator is connected to the second input of the first adder, and the data input unit connected by its outputs to the second inputs of the third adder, divider, second adder and the first and second multipliers, respectively.

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