KR102442543B1 - Mobile GPR exploration apparatus - Google Patents

Abstract

The present invention relates to a mobile GPR exploration device (1). The mobile GPR exploration device (1) comprises: a main body (3) to which a wheel (31) is mounted; antennas (4a, 4b) provided in the main body (3) to emit or receive electromagnetic pulses; a pulse generating module (5) for generating electromagnetic pulses; a pulse receiving unit (6) for receiving reflected waves and converting the reflected waves into digital signals; a control FPGA module (7) for controlling the pulse generating module (5) and the pulse receiving unit (6) and generating control pulses; laser units (4, 8) which are two laser modules provided in the main body (3), wherein one laser module has a structure that can rotate in the left and right directions, and the other laser module is fixed, so that the driving direction is identified by comparing two lines of laser light generated from each laser module; an encoder module (17) for interlocking with the wheel (31) to generate signals at regular intervals; a mobile device (2) for interlocking with the main body (3) to transmit and receive the signals; a main micro-control unit (16) for controlling the GPR exploration device; and a handle (33) connected to the main body (3). Accordingly, exploration can be conducted even in a narrow exploration area.

Description

Mobile GPR exploration apparatus

The present invention relates to a mobile GPR exploration device, and more particularly, by improving the structure, it has two laser modules, one laser module is rotatable in the left and right direction, and the other laser module is fixed from each laser module by being fixed. It relates to a technology that can determine the driving direction by comparing the generated two lines of laser light, and can easily explore the reinforcement structure or peeling state of reinforcing bars inside the outer wall or floor of a facility.

In general, the outer walls of high-rise buildings, floor floors, dams, and bridges deteriorate over time, and cracks occur on the surface or the backfilling inside the outer wall is deformed. Repair and reinforcement are carried out.

A method of detecting the state of such an outer wall or floor layer is mainly conducted by using seismic waves or a GPR probe (Ground Penetrating Radar).

At this time, since the frequency of the probe wave is located in the range of several KHz to several MHz, it is not suitable for the exploration of buried objects shorter than the wavelength of the frequency. It is being actively used for water and pore exploration.

Among them, a frequency of 1.6 GHz or higher is generally used to investigate the reinforcement of the concrete structure exterior wall or floor or the thickness of the slab. The size of the antenna that emits electromagnetic pulses of this frequency can be made as small as 10 cm or less, so the size of the GPR probe is usually hand-held and small.

However, the general conventional GPR exploration equipment is small in size, but it has a display and is equipped with 4 wheels. more than double the volume.

In addition, if the exploration equipment weighs more than 1-2 kg and long-distance exploration of the ceiling area using an extension stick is performed, it is not suitable for long-term exploration because it is not suitable for long-term exploration. It is also not easy to check in real time.

And, in general, since GPR probes need to transmit and receive signals with accurate timing inside, a field programmable gate array (FPGA) circuit is used to control peripheral IC circuits.

FPGAs are semiconductor devices made up of programmable logic devices. FPGAs are composed of numerous logic blocks and provide the ability to perform various hardware configurations. In each logic block, a gate, flip-flop, memory, etc. that can implement a circuit are arranged.

The existing IC chip performs only a set function, but the FPGA is a control means widely used in GPR exploration equipment because it is easy to configure the circuit variably.

The wiring regions of these FPGAs transmit signals to and from logic blocks. The operation speed of a digital circuit is greatly affected by the length of the wiring. Since the logical blocks are physically arranged at regular intervals, the delay time between adjacent logical blocks is constant.

Also, the delay time between input/output is the same when passing through a logic block composed of the same logic circuit. By using this to continuously pass a signal through a logic block, a signal with a constant delay time can be created.

And there are several sampling techniques used in GPR. The real-time sampling technique with the shortest acquisition time, the time-interleaved sampling technique that requires several ADCs, and the equivalent-time sampling technique that requires a large number of acquisition samples are the most used.

The real-time sampling technique is the method of sampling the input signal at once depending on the sampling performance of the ADC, and it shows the fastest speed. However, if the target resolution is picosecond scale, it has to use a very expensive ADC circuit or it may be impossible to implement, so it is not practical.

The Time Interleaved sampling technique samples the input signal with a number of ADCs using a slightly delayed sampling clock and combines the sampled results through post-production to derive the final sampling result. If the target resolution is high, the ADC circuit is required as much as the resolution in proportion to it, so the economic feasibility is very low, so it is used for military use or equipment with relatively low resolution.

Finally, the Equivalent Time Sampling (ETS) technique collects data as much as the desired resolution using one ADC using a sampling clock that is slightly delayed while the input signal is being repeated, and collects the signal through post-production. It is a method of obtaining the sampled result of the target resolution by summing it up. It operates the slowest because the input signal has to be used repeatedly, but it is the cheapest and the best method in the environment where the operation cycle can be applied at a speed higher than the user's desired speed. This equivalent time sampling technique can be said to be most suitable for GPR exploration work, which is relatively slow.

However, the conventional GPR probe has the following problems.

First, the existing GPR exploration device has a problem in that it is difficult to explore in a narrow exploration area because it is difficult to enter a space such as a narrow alley because it has a large size as it is provided with a display unit and a control unit.

Second, since the handle of the exploration device is a fixed method, there is a problem in that there is a limitation in the exploration when the length of the handle needs to be increased.

Third, since the general ETS ADC technique acquires data while directly delaying the sampling clock of the ADC, there is a problem in that an expensive ADC whose input frequency specification is higher than the target sampling frequency must be used in order to acquire data at the correct timing.

Fourth, there is a problem in that it is difficult to actually check the driving conditions such as the driving direction and the driving angle of the exploration device when a curved section is performed in the case of detecting by driving the probe.

Patent Application No. 10-2005-45172 (Name: Wireless measurement system for dynamic response measurement for monitoring of structures)

Therefore, the present invention has been proposed to solve these conventional problems, and the object of the present invention is to improve the structure by mounting two laser modules so that one laser serves as a reference line and the other laser displays the actual travel direction. By comparing the two lasers with each other, it is easy to check whether or not the laser is going straight, and thereby, it is possible to easily reach the position of the reinforcing bar inside the outer wall or floor of the facility. will be.

In order to realize the above object of the present invention, the exploration apparatus according to an embodiment of the present invention, the wheel 31 is mounted body 3 and;

Antenna (4a, 4b) provided in the main body (3) for emitting or receiving electromagnetic pulses;

a pulse generating module 5 for generating electromagnetic pulses;

a pulse receiving unit 6 that receives the reflected wave and converts it into a digital signal;

a control FPGA module 7 for controlling the pulse generating module 5 and the pulse receiving unit 6 and generating a control pulse;

As two laser modules provided in the main body 3, one laser module has a structure rotatable in the left and right directions, and the other laser module is fixed by comparing two laser beams generated from each laser module to determine the driving direction. a laser unit (4, 8);

an encoder module 17 for generating a signal at regular intervals in conjunction with the wheel 31;

a mobile device (2) for transmitting and receiving signals in conjunction with the main body (3);

a main micro control unit 16 for controlling the GPR probe; and

and a handle 33 connected to the body 3 .

Mobile GPR exploration apparatus according to an embodiment of the present invention has the following advantages.

First, by installing two laser modules in the exploration device, one laser acts as a reference line and the other laser displays the actual direction of travel, so that the two lasers can be compared with each other, so it is easy to check whether the probe is going straight or not. It is possible to easily reach the location of the reinforcing bar inside the outer wall of the facility or the floor, so it is possible to easily explore the reinforcing structure and the detached state of the reinforcing bar.

Second, by omitting the display and the control unit in the GPR exploration device, and folding the holder on the handle, the mobile computer can be mounted on the holder so that the size can be miniaturized, so that exploration can be carried out in a narrow exploration area.

Third, by improving the handle of the exploration device to an extendable structure, it is convenient to use without being constrained by the environment of the exploration area.

Fourth, in the GPR pulse receiver, the ADC used in the ETS ADC technique and the equivalent sampling module with the track-and-hold circuit using the SRD control pulse as a switch are used, so that even a low-speed ADC can be used without being limited by the input frequency specification. .

Fifth, by arranging a plurality of delay cells applied to the GPR control FPGA module, the number of bits of the control signal can be adjusted to create a signal with various delay times.

1 is a perspective view showing the appearance of a mobile GPR exploration device according to an embodiment of the present invention.
FIG. 2 is a side view of the mobile GPR exploration device shown in FIG. 1 .
3 is an exploded perspective view showing the structure of the laser unit of the mobile GPR exploration device shown in FIG. 1 .
FIG. 4 is a side view showing the arrangement structure of the first and second laser modules shown in FIG. 3 .
5 is a partially enlarged perspective view showing a structure in which the first and second laser modules of the laser unit shown in FIG. 4 are combined.
6 is a plan view of the mobile GPR exploration apparatus shown in FIG.
7 is a partial perspective view illustrating a coupling relationship between a knob for adjusting the vertical rotation angle of the second laser module of the laser unit and the second laser module.
8 is a perspective view schematically illustrating a coupling relationship between the second laser module and the angle knob knob shown in FIG. 7 .
9 is a diagram schematically showing a circuit structure provided in the mobile GPR exploration apparatus shown in FIG. 1 .
FIG. 10 is a circuit diagram schematically showing the structure of the equivalent sampling module shown in FIG. 9 .
11 is a circuit diagram schematically showing the structure of the SRD control pulse circuit shown in FIG. 10 .
12 is a perspective view showing a structure in which an extension stick is connected to the mobile GPR exploration device shown in FIG. 1 .
13 is a partially enlarged perspective view showing the structure of a holder provided in the extension stick shown in FIG. 12 to attach and detach the mobile device.
14 is a diagram showing a Delay generator of the control FPGA module shown in FIG. 9 .
15 is a diagram illustrating an operating principle of the equivalent sampling module shown in FIG. 10 .
16 is a diagram illustrating a principle of applying a slightly delayed sampling pulse to a continuous input wave during equivalent time sampling.
17(a), (b), and (c) are diagrams illustrating a search screen implemented on a display of the mobile device shown in FIG. 1 .

Hereinafter, a GPR exploration apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in Figures 1 to 17, the GPR exploration device 1 proposed by the present invention emits an electromagnetic pulse to the surface to be surveyed and receives and analyzes the reflected wave, thereby reinforcing the structure or peeling of the reinforcing bar inside the outer wall or floor of the facility. status can be explored.

This GPR exploration device (1) has a main body (3) and; Antenna (4a, 4b) provided in the main body (3) for emitting or receiving electromagnetic pulses; a pulse generating module 5 for generating electromagnetic pulses; a pulse receiving unit 6 that receives the reflected wave and converts it into a digital signal; a control FPGA module 7 for controlling the pulse generating module 5 and the pulse receiving unit 6; As two laser modules provided in the main body 3, one laser module has a structure rotatable in the left and right directions, and the other laser module is fixed by comparing two laser beams generated from each laser module to determine the driving direction. a laser unit (4, 8); a wheel (31) provided on the body (3); an encoder module 17 for generating a signal at regular intervals in conjunction with the wheel 31; a mobile device (2) for transmitting and receiving signals in conjunction with the main body (3); a wireless communication module for transmitting and receiving signals to and from the mobile device 2; a control unit 16 for controlling the GPR probe; and a handle 33 connected to the body 3 .

In more detail,

The antennas 4a and 4b are composed of a transmitting antenna 4a for transmitting a pulse signal and a receiving antenna 4b for receiving the pulse signal. It is preferable that these transmit and receive antennas 4a and 4b be shielded.

The pulse generating module 5 may be configured as an avalanche pulse generator or an SRD pulse generator capable of generating a GPR pulse signal, or a combination of both may be used.

The pulse generating module 5 must synchronize the timing with the pulse receiving unit 6, and the control FPGA module 7 generates an operation trigger signal of the pulse generating module 5 and the pulse receiving unit 6 Synchronize the operating timing.

Then, the pulse generating module 5 generates one electromagnetic pulse whenever it receives a trigger signal transmitted from the control FPGA module 7 and passes through a Balun circuit to match the impedance. These pulse waves are finally radiated to the probe surface through the transmitting antennas 4a and 4b.

The pulse receiving unit 6 includes: an LNA (Low Noise Amplifier) 14 for converting a signal into an appropriate voltage value that can be sampled after impedance matching is achieved at the receiving antennas 4a and 4b; an equivalent sampling module 15 for transmitting a high-speed sampling signal with only a short instantaneous voltage value of the input pulse; And it includes an ADC 12 that receives only one voltage value and performs sampling regardless of the input frequency limit.

The pulse receiving unit 6 receives a signal through the receiving antennas 4a and 4b, and is operated by the ETS ADC technique.

In more detail, the LNA 14 converts a signal into an appropriate voltage value that can be sampled after impedance matching is achieved in the reception antennas 4a and 4b. The LNA 14 has a structure of two amplification stages, and an input signal can be amplified by the amplification stage by the control signal of the main MCU 16 or passed without being amplified.

Then, the signal passing through the LNA 14 (hereinafter, an input pulse) is converted into an appropriate voltage value and input to the equivalent sampling module 15 .

The equivalent sampling module 15 serves to send only a short instantaneous voltage value of the input pulse to the low-speed ADC 12 so that high-speed sampling of 10 GHz or higher can be performed using the low-speed ADC.

That is, the input pulse 8 input to the pulse receiving unit 6 is first sampled from the reference clock 9, and the next input pulse is sampled by the clocks 10 and 11 that are slightly delayed than the reference clock. . All sampled data are then combined and finally sorted into one high-speed sampled data value.

In general, the ADC used in this ETS ADC technique does not care if the sampling clock specification is low, but the input frequency specification must be higher than the target sampling frequency to accept the input value.

Therefore, at least the input frequency specification should use an ADC higher than the target sampling frequency. In this embodiment, the equivalent sampling module 15 is disposed in front of the ADC 12 so that it can be used even with a low-speed ADC.

That is, the equivalent sampling module 15 includes a current amplification stage 23; an SRD control pulse circuit 13; a track and hold circuit 27; Includes a buffer (Buffer; 24).

The track and hold circuit 27 using the high-speed SRD control pulse 47 using the SRD as a switch holds the input signal of a very short time in the buffer 24 and then transmits it to the low-speed ADC 12 .

As the input signal passes through the LNA 14 , the voltage is amplified, and while passing through the Current Amp 23 , the current is amplified to a size interpretable by the low-speed ADC 12 .

In addition, the SRD control pulse circuit 13 includes: SRD Switch Circuit 48 operating with a differential sampling clock (+/- BASIC SAMPLE CLK; 51; 52) from the GPR control FPGA module 7; a power amplifier (PA; 49) which removes the noise of the switch signal from the SRD Switch Circuit (48) and amplifies only the switch signal; It consists of a feedback circuit including a duplex (Duplexer; 50).

The SRD control pulse circuit 13 receives the basic sample clock from the GPR control FPGA module 7 in a differential signal method and generates a high-speed sampling clock having a smaller clock width than the basic sample clock in the SRD Switch Circuit 48 .

In this case, the generated clock has a problem in that the signal strength is attenuated or noise is generated due to an impedance difference generated in each device or an inflow of noise.

After putting the signal into the duplexer 50 , an unnecessary frequency region is removed with an internal 4-stage band pass filter of the duplexer 50 , and only the desired frequency region is transmitted to the track and hold circuit 27 .

After transmission, the feedback signal is passed through the PA (Power Amplifier; 49), put into the Duplexer 50 again, amplified only the frequency range to be used, and then transmitted again to the Track and Hold (27) circuit to finally make noise. Stable operation is possible with the amplified sampling clock from which is removed.

And, the signal processed by the equivalent sampling module 15 is input to the ADC 12, and the ADC 12 receives only one voltage value corresponding to an instant of 50 ps or less as an input, and is sampled regardless of the input frequency limit. This becomes possible.

After sampling one voltage value in this way, the ETS ADC technique is applied to sequentially sample the voltage values that have been delayed little by little, and then the data are combined to make one complete pulse data.

On the other hand, the control FPGA module 7 controls the pulse generating module 5 and the pulse receiving unit 6, and generates a control pulse.

The control FPGA module 7 generates a control pulse by a delay cell 26 as shown in FIG. 14 .

That is, the control FPGA module 7 includes a plurality of delay cells 26 for generating control pulses; It includes a multiplexer (28) that receives multiple signals and sends them to a single line or splits the single line signal back into the original signal.

One delay cell 26 has a delay of 50ps and generates a control pulse by generating a necessary delay value through a combination of Delay Cells.

The delay cell 26 is composed of at least one or more logical blocks, for example, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512. do.

In addition, a multiplexer (Mux) 28 is connected to the delay cell 26, and the multiplexer receives multiple signals and sends them to a single line or separates the signals of the single line back into original signals.

When the corresponding bit of the control signal through the Mux 28 is 1, a signal passing through the internal delay cell 26 is selected, and when it is 0, a signal not passing through the internal delay cell is selected.

If the signal selection process is described as an example, a total of 1024 types of delay clocks are generated by passing the logic block 0 times, 1 time, 2 times, ... 1024 times with a combination of the 10-bit control signal.

In this way, it is possible to create a signal with various delay times by adding a delay cell composed of 2^n logic blocks and adjusting the number of bits of the control signal.

And, the exploration data acquired from the control FPGA module 7 is stored in the storage medium 29 of the GPR exploration device, and also wirelessly to the mobile device 2 through the main MCU 16 and the wireless communication module 19. is sent

The main MCU 16 controls the laser module 18 to display a laser point guiding the exploration line on the front floor.

And, the encoder module 17 is connected to the wheel 31 to adjust the radiation interval of the pulse.

The encoder module 17 may be a mechanical encoder or a non-contact encoder such as a laser or an optical sensor.

The encoder module 17 can emit and acquire pulses at various intervals whenever it moves a certain distance by being connected to the wheel 31 , and transmits the probe timing to the control FPGA module 7 .

On the other hand, the mobile device 2 transmits and receives signals by the main body 3 and the wireless communication module 19 .

The mobile device 2 can be used as a tablet or laptop computer capable of wireless communication, a notebook computer, a mobile phone, etc., and the acquired data is separately stored in the storage medium 29 of the GPR probe, so the mobile computer is replaced with other equipment It is possible to share previously acquired data together.

The mobile device 2 includes a display 22 , a unit 21 on which an acquisition program is mounted, and a communication module 20 .

The display 22 is an LED, etc., and displays an image of the probed ground.

These images are processed by the acquisition program mounted in the unit 21, and the acquisition program 21 displays the inside of the exploration target while horizontally scrolling the 2D exploration screen as shown in FIG. 17(A).

And, in general, when electromagnetic pulses are used for exploration, the shape of the reflector is displayed in the form 37 spread in the exploration direction. It provides a function of converting to the form 38, and when a certain area is explored with a mesh structure, the internal structure of the corresponding area can be viewed in the top view form as shown in FIG. 17(C).

On the other hand, the laser unit (4, 8) is mounted on the front of the main body to indicate whether or not to go straight by two laser points.

These laser units 4 and 8 are disposed in the receiving groove 53 of the main body 3, are coupled to the rotation shaft S of the motor M, and are rotatable in the left and right directions by interlocking with the gyro sensor 50, a first laser module 4 for presenting a reference line with a laser; a second laser module 8 that is fixedly arranged in the left and right directions at an adjacent position of the first laser module 4, and that the angle can be adjusted in the vertical direction to suggest the direction in which the probe actually travels with the laser; a connector 9 disposed inside the receiving groove 53 and connected to the front of the second laser module 8 to rotate in the vertical direction; The angle adjustment knob 10 for fixing the second laser module 8 by rotating the second laser module 8 in the vertical direction at a predetermined angle during rotation by passing the connector 9 through the through hole h1 formed in the receiving groove 53 in the lateral direction. )Wow; And, it includes a rubber packing (10b) inserted into the outer peripheral surface of the shaft (10a) to prevent the shaft (10a) from arbitrarily rotating by frictional force.

In more detail,

The first laser module 4 is connected to the gyro sensor 50 and the motor M to detect a rotation angle when the main body 3 rotates in the left and right directions. Then, the sensed angle value is transmitted to the control unit 16, and the control unit 16 controls the motor M so that the rotation shaft S of the motor M is rotated by a predetermined angle in the opposite direction to the rotation direction. That is, even when the exploration device travels in a curved direction, the first laser module 4 rotates in the opposite direction to the traveling direction by the rotation of the rotation shaft S of the motor M, rather than in the curved direction along the exploration device. The first laser module 4 always faces forward.

Accordingly, the first laser module 4 compensates for the rotation angle of the main body 3 and maintains its position, so that the laser irradiated from the first laser module 4 always displays the front of the exploration device.

On the other hand, the second laser module 8 is mounted on the main body by the connector 9 so that it flows only in the vertical direction and is fixed in the left and right directions. Accordingly, since the laser irradiated from the second laser module 8 is directed in the curved direction as in the case where the exploration device travels in the curved direction, the direction of travel of the exploration device is always displayed.

The second laser module 8 can be angled in the vertical direction while being fixed to the main body 3 by the connector 9 .

At this time, angle adjustment is possible in various ways, for example, angle adjustment is possible by the angle adjustment knob (10) and the rubber packing (10b).

In more detail, the connector 9 is accommodated in the receiving groove 53 formed in the main body 3 , and the second laser module 8 is mounted in front.

And, a fixing hole (h) is formed through the lateral direction of the connector 9, and the shaft 10a of the angle adjustment knob 10 is inserted and penetrated into the fixing hole (h). At this time, the shaft 10a of the angle adjustment knob 10 passes through the through hole h1 of the receiving groove 53 formed in the front of the body 3 and the fixing hole h of the connector 9 . Then, a screw thread is formed at the tip 10c of the shaft 10a, and the bolt B is fastened to the screw thread.

And, a fastening hole h2 is formed in the inside of the connector 9 in the longitudinal direction, and the fixing bolt B1 is fastened to the rear end 54 of the second laser module 8 through this fastening hole h2. can As the fixing bolt B1, various types of bolts are applicable, for example, a mood bolt may be applied.

Then, the second laser module 8 is inserted into the connector 9, and the rear end 54 penetrates the hole h3 formed in the shaft 10a and is coupled with the fixing bolt B1.

At this time, by inserting a rubber packing (10b) into one side of the outer peripheral surface of the shaft (10a), the shaft (10a) is prevented from arbitrarily rotating by the frictional force between the knob (10) and the bracket (56) protruding from the front of the body (3) can do.

In the case of adjusting the angle of the second laser module 8 by the angle adjusting knob 10 having such a structure, first, the rubber packing 10b is inserted and the fixed knob 10 is rotated at a target angle to rotate the second The laser module 8 is fixed at a predetermined angle. At this time, by partially releasing the bolt (B), the shaft (10a) of the knob (10) can be rotated and then fastened again.

In this way, the second laser module 8 can be fixed by adjusting it at a predetermined angle up and down by the connector 9 and the angle adjusting knob 10 .

As described above, since the second laser module 8 has a fixed structure in the left and right directions, even when the exploration apparatus travels in the curved direction, it is directed in the curved direction as well, so that the traveling direction of the exploration apparatus is displayed.

As a result, the first laser module 4 rotates at a certain angle in the opposite direction to the driving direction during curved driving by interlocking with the gyro sensor 50 and the motor M to correct the curvature of the curved main road so that it always faces in a straight direction. Since the front is displayed, and the second laser module 8 displays only the traveling direction of the exploration device, the current attitude of the exploration device is compared by comparing the two lasers irradiated from the first and second laser modules 4 and 8 with each other. can be checked in real time.

At this time, it is preferable that the light generated by the first and second laser modules 4 and 8 be of different colors so that they can be easily distinguished. Of course, it is also possible to use the same color.

On the other hand, as shown in FIGS. 12 and 13, the handle 33 is connected to the main body 3 so that the operator can hold the handle 33 and conduct the exploration, and the handle 33 is the main body ( It can be connected to the top or rear of 3).

And, the handle 33 can be extended in length by connecting an extension tube as needed. That is, it is difficult for the GPR probe to reach the ceiling or a high place, making it difficult to conduct exploration. In this case, an extension tube is connected to the handle 33 and used.

This extension tube may be integrally fixed to the upper end of the handle 33 by a fastener. In this case, the fastener may be fixed in various forms, for example, by a snap pin, a ring, or the like.

In addition, the handle 33 or the extension tube is provided with a holder capable of detachably mounting the mobile device 2 .

The holder includes an insert 44 in which an insertion groove 42 is formed so that the mobile device 2 can be inserted; It includes a support 46 for supporting the lower portion of the insert 44 at various angles.

In addition, the upper portion of the support 46 is connected to the lower surface of the holder by forming a rotating sphere, and the lower portion is connected to the handle 33 by a hinge pin 35 .

Accordingly, the mobile device 2 is inserted into the insertion groove 42 , and the holder can be folded or unfolded around the hinge pin 35 as needed.

Hereinafter, the operation process of the GPR exploration apparatus according to an embodiment of the present invention will be described in more detail.

As shown in FIGS. 1 to 17, when exploring the reinforcement structure or peeling state of reinforcing bars inside the outer wall or floor layer of the facility using the GPR exploration device, first, the power button 32 mounted on the rear side of the main body 1 ) is turned on to drive the GPR probe.

Then, the vertical position of the second laser module 8 is adjusted before the exploration device 1 is driven. That is, after partially releasing the bolt (B) fastened to the tip of the shaft (10a), the knob 10 is rotated to rotate the second laser module 8 to a target angle, and when rotated at the corresponding angle, the bolt ( B) fasten it in place by fastening it. At this time, by inserting a rubber packing (10b) into one side of the outer peripheral surface of the shaft (10a), the shaft (10a) is prevented from arbitrarily rotating by the frictional force between the knob (10) and the bracket (56) protruding from the front of the body (3) can do.

In addition, the first laser module 4 is in a state interlocked with the gyro sensor 50 and the motor (M).

In this state, by operating the first and second laser modules 4 and 8, two lines of laser light are irradiated forward. At this time, it can be easily distinguished by different colors of the two lines of laser light.

In the initial stage of driving, two lines of laser light are irradiated in the same direction.

When driving in this state and proceeding along a curved path, the gyro sensor 50 mounted on the exploration device detects the curvature of the curved path, and the control unit 16 controls the first laser module 4 according to the curvature value. is calculated, and the calculated value is transmitted to the motor M to rotate the first laser module 4 in the reverse direction to the traveling direction.

Therefore, the laser light generated by the first laser module 4 always irradiates the front of the exploration device.

On the other hand, since the second laser module 8 is fixed by the connector 9 at the front of the exploration device, it always irradiates the same direction as the traveling direction of the exploration device.

Accordingly, when the exploration device travels on a curved path, the laser light generated by the second laser module 8 is irradiated in the traveling direction of the exploration device.

As a result, in a curved line, the laser light irradiated from the first laser module 4 indicates a straight line direction, so it becomes a reference line, and since the laser light irradiated from the second laser module 8 displays a curved direction, it becomes an actual traveling line. , by comparing the two laser beams with each other, it is possible to grasp the current driving direction and driving angle of the probe in real time.

On the other hand, as the exploration device travels in this way, the exploration for the surface of the earth is started.

First, the acquisition program mounted on the unit 21 of the mobile device 2 is executed, and the GPR exploration apparatus and the network are connected.

Then, by clicking the menu on the display 22, it enters the acquisition mode and changes to the Ready state.

In this state, hold the handle 30 of the GPR exploration device and push the equipment in the exploration direction to rotate the wheel 31 to start the GPR exploration.

First, the pulse generating module 5 needs to synchronize the timing with the pulse receiving unit 6, so the control FPGA module 7 generates an operation trigger signal of the pulse generating module 5 and the pulse receiving unit 6 to operate Synchronize the timing.

Then, the pulse generating module 5 generates one electromagnetic pulse whenever it receives a trigger signal transmitted from the control FPGA module 7 and passes through a Balun circuit to match the impedance. These pulse waves are finally radiated to the probe surface through the transmitting antennas 4a and 4b.

At this time, since the encoder module 17 is mounted on the wheel 31 , it is possible to emit and acquire pulses at various intervals whenever it moves a certain distance, and transmits this signal to the control FPGA module 7 .

The pulse wave radiated to the probe surface as described above is received by the pulse receiver 6 through the reception antennas 4a and 4b of the GPR probe again after reflection.

The pulse receiving unit 6 receives signals through the receiving antennas 4a and 4b, and data is acquired by the sampling method of the present invention described above.

In more detail, the LNA converts a signal into an appropriate voltage value that can be sampled after impedance matching is achieved at the reception antennas 4a and 4b.

Then, the signal passing through the LNA 14 (hereinafter, an input pulse) is converted into an appropriate voltage value and input to the equivalent sampling module 15 .

The equivalent sampling module 15 serves to send only a short instantaneous voltage value of the input pulse to the low-speed ADC 12 so that a high-speed sampling signal of 10 GHz or higher can be performed using the low-speed ADC.

That is, the input pulse 8 input to the pulse receiving unit 6 is first sampled at the reference clock 9, and the next input pulse is sampled by the clocks 10 and 11 that are slightly delayed than the reference clock. . All sampled data are then combined and finally sorted into one high-speed sampled data value.

In this embodiment, the equivalent sampling module 15 is disposed in front of the ADC 12 so that it can be used even in a low-speed ADC.

Accordingly, as the input signal passes through the LNA 14 , the voltage is amplified, and while passing through the Current Amp 23 , the current is amplified to a size that can be interpreted by the low-speed ADC 12 .

And, the ADC 12 receives only one voltage value corresponding to an instant of 50 ps or less as an input, and sampling is possible regardless of the input frequency limit.

After sampling one voltage value in this way, the ETS ADC technique is applied to sequentially sample the voltage values that have been delayed little by little, and then the data are combined to make one complete pulse data.

Meanwhile, the SRD control pulse circuit 13 receives the basic sample clock from the GPR control FPGA module 7 in a differential signal method and generates a high-speed sampling clock having a smaller clock width than the basic sample clock in the SRD Switch Circuit 48 .

In this case, the generated clock has a problem in that the signal strength is attenuated or noise is generated due to an impedance difference generated in each device or an inflow of noise.

After putting the signal into the duplexer 50 , an unnecessary frequency region is removed with an internal 4-stage band pass filter of the duplexer 50 , and only the desired frequency region is transmitted to the track and hold circuit 27 .

After transmission, the feedback signal is passed through the PA (Power Amplifier; 49), put into the Duplexer 50 again, amplified only the frequency range to be used, and then transmitted again to the Track and Hold (27) circuit to finally make noise. Stable operation is possible with the amplified sampling clock from which

On the other hand, the control FPGA module 7 controls the pulse generating module 5 and the pulse receiving unit 6, and generates a control pulse by combining the delay cell (Delay Cell; 26).

That is, the delay cell 26 is composed of at least one or more logical blocks, for example, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512. make up

In addition, a multiplexer (Mux) 28 is connected to the delay cell 26, and the multiplexer receives multiple signals and outputs one of them as an output.

When the corresponding bit of the control signal through the Mux 28 is 1, a signal passing through the internal delay cell 26 is selected, and when it is 0, a signal not passing through the internal delay cell is selected.

If the signal selection process is described as an example, a total of 1024 types of delay clocks are generated by passing the logic block 0 times, 1 time, 2 times, ... 1024 times with a combination of the 10-bit control signal.

The signal processed in this way is transmitted to the mobile device 2 by the wireless communication module 19 .

Then, as processed by the acquisition program mounted in the unit 21, the acquisition program 21 can display the inside of the exploration target while horizontally scrolling the 2D exploration screen as shown in FIG. 17A.

Alternatively, as shown in FIG. 17(B), it provides a function of converting to the form 38 of the original buried material by applying the migration technique, and when a certain area is explored with a mesh structure, as shown in FIG. 17(C) You can see the internal structure of the area in the top view form.

Claims (5)

a body 3 on which the wheel 31 is mounted;
Antenna (4a, 4b) provided in the main body (3) for emitting or receiving electromagnetic pulses;
a pulse generating module 5 for generating electromagnetic pulses;
a pulse receiving unit 6 that receives the reflected wave and converts it into a digital signal;
a control FPGA module 7 for controlling the pulse generating module 5 and the pulse receiving unit 6 and generating a control pulse;
A first laser module 4 provided in the main body 3, coupled to the rotation shaft S of the motor M, and rotatable in the left and right directions by interlocking with the gyro sensor 50 to present a reference line with a laser; The first and second laser modules (4, 8) by including a second laser module (8) that is fixedly arranged in the left and right directions at an adjacent position of the first laser module (4) and provides a direction in which the exploration device travels with a laser A laser unit (4, 8) for determining the traveling direction by comparing the two lines of laser light generated from the;
an encoder module 17 for generating a signal at regular intervals in conjunction with the wheel 31;
a mobile device (2) for transmitting and receiving signals in conjunction with the main body (3);
a main micro control unit 16 for controlling the GPR probe; and
GPR exploration device comprising a handle (33) connected to the body (3). The method of claim 1,
The laser units 4 and 8 are disposed in the receiving groove 53 of the main body 3, are coupled to the rotation shaft S of the motor M, and are rotatable in the left and right directions by interlocking with the gyro sensor 50, so that the laser a first laser module (4) for presenting a reference line; a second laser module 8 that is fixedly arranged in the left and right directions at an adjacent position of the first laser module 4, and that the angle can be adjusted in the vertical direction to suggest the direction in which the probe actually travels with the laser; a connector 9 disposed inside the receiving groove 53 and connected to the front of the second laser module 8 to rotate in the vertical direction; The angle adjustment knob 10 for fixing the second laser module 8 by rotating the second laser module 8 in the vertical direction at a predetermined angle during rotation by passing the connector 9 through the through hole h1 formed in the receiving groove 53 in the lateral direction. )Wow; And, the GPR exploration device including a rubber packing (10b) inserted into the outer peripheral surface of the shaft (10a) to prevent the shaft (10a) from arbitrarily rotating by frictional force. 3. The method of claim 2,
A fixing hole (h) is formed in the lateral direction of the connector (9), the shaft (10a) of the angle adjustment knob (10) passes through and is fixed by a bolt (B), and a fastening hole ( h2) is formed, the rear end 54 of the second laser module 8 is inserted and fastened by the fixing bolt B1, and the fixing bolt B1 penetrates the hole h3 formed in the shaft 10a to 2 GPR probe coupled to the rear end 54 of the laser module (8). The method of claim 1,
The pulse generating module 5 may combine an avalanche pulse generator or an SRD pulse generator capable of generating a GPR pulse signal, or both,
The pulse receiving unit 6 includes: an LNA (Low Noise Amplifier) 14 for converting a signal into an appropriate voltage value that can be sampled after impedance matching is achieved at the receiving antennas 4a and 4b;
an equivalent sampling module 15 for transmitting only a short instantaneous voltage value of the input pulse; and
A GPR probe including an ADC (12) that receives only one voltage value and performs sampling regardless of the input frequency limit. 5. The method of claim 4,
Equivalent sampling module 15 includes a current amplification stage 23; an SRD control pulse circuit 13; a track and hold circuit 27; Including a buffer (Buffer; 24),
The SRD control pulse circuit 13 includes: an SRD Switch Circuit 48 operating with a differential sampling clock (+/- BASIC SAMPLE CLK; 51; 52) from the GPR control FPGA module 7; a power amplifier (PA; 49) which removes the noise of the switch signal from the SRD Switch Circuit (48) and amplifies only the switch signal; GPR probe including a duplex (Duplexer; 50).

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