KR20040092508A - System for investigation of river bottom topography and fluctuation using GPS and GPR - Google Patents

Abstract

PURPOSE: A system for investigation of river bottom topography and fluctuation using GPS and GPR(ground penetrating radar) is provided to perform an accurate investigation process without an error by storing and utilizing the information obtained from the GPS and the GPR. CONSTITUTION: An aquatic moving unit(10) is moved on surface of water. A GPR(20) is installed on the aquatic moving unit and includes a control unit and a transmitting/receiving radar. A GPS(30) is installed on the aquatic moving unit to calculate position information. An information processing unit(40) exchanges data between the GPR and the GPS. The information processing unit includes a data storage part for storing topographical information and position information, a map storage part for storing an electronic map, a topographical map generator for generating a river bottom topography map, and an output unit for outputting the river bottom topography map.

Description

System for investigation of river bottom topography and fluctuation using GPS and GPR}

The present invention relates to a riverbed ground survey system for the ground exploration of the lower part of the river, and more specifically, to investigate the location and sedimentary layer information of the bedrock bedrock using a geotechnical radar (GPR) device and a GPS device The present invention relates to a riverbed ground survey system that can create a riverbed topographical map more accurately and easily.

At present, various fields such as civil engineering and water resources development require accurate information on the topography and stratification of the bottom of the river. According to these needs, various grounds and equipments are used to explore the ground of the bottom of the river. For example, in the civil engineering field where a structure such as a bridge should be installed on the upper part of a river, it is necessary to accurately grasp the position and depth of the bedrock for supporting the foundation prior to the installation of the structure. In the case of harvesting, accurate information on the distribution and deposition of sand layers is required for the prediction of the harvestable amount and economic feasibility. In addition, information on the distribution status, total sediment volume, and trends of changes in the sediment under the river is important as a basis for dredging planning.

The riverbed ground survey system is a system for investigating the ground information of the bottom surface of the river as above, and collects data on the ground under the surface of the river using exploration equipment on the surface of the river to be investigated and analyzes the collected data. This refers to a system for providing bottom surface information such as depth, bedrock location and sedimentary information.

In general, for the exploration of the lower and lower terrains, civil engineering works by directly boring the bottom and analyzing the collected samples to investigate the layer structure and the location and type of bedrock on the bottom, but the equipment used is expensive. There is a problem that requires a skilled technician to operate the operation, and if it is necessary to investigate the topography of the river over a certain area, it takes a long time to survey the entire area.

Therefore, it is common to use a seabed survey method in which exploration equipment is mounted on a water transport vehicle such as a boat and analyzes the collected data and indirectly obtains information about the bottom ground without directly examining the bottom. The exploration equipment used in such a system is sound depth measurement equipment using sound waves. The depth can be easily obtained by using such sound waves, while the limits of penetration force are used for those equipments using frequencies around 12 KHz. Due to this problem, it is difficult to investigate the bed sediment. In addition, the SBP (Sea Bottom Profiler), which uses a frequency of about 3.5KHz to investigate the bottom sediment under the sea floor, has a problem that it is not suitable for examining small and medium sized river sediments due to its large equipment.

Therefore, a method of applying ground penetrating radar (GPR) developed for the purpose of exploration of underground buried grounds has been proposed to be used for the exploration of the lower ground. GPR has been mainly used for the identification of geological structures on land, non-destructive testing of structures, and the exploration of underground deposits. However, the use of GPR is also increasing for the investigation of sediments and depths in riverbed or lake. The method emits electromagnetic waves from the GPR and measures the intensity and reception time of the reflected waves reflected back from the bottom interface with different electrical properties, and then determines the bottom thickness, topography, and the like from the bottom. It is possible to obtain a high resolution image for a continuous stream in the case where a shallow depth and relatively high resolution is required, such as the river of the present invention has the advantage that it is excellent in utility and very economically applicable.

On the other hand, when irradiating the ground under the ground using the GPR as described above, by moving the boat along the preset side line, the reflected wave information is received by radiating from the GPR, and the information is transferred to an information processing apparatus such as a computer loaded with an analysis program. By means of data processing and analysis, a continuous bottom topography profile can be obtained over the lateral direction. However, in such a method, a small vessel such as a boat is used and observation is performed while moving it on the surface of the water, and it is very difficult to accurately move while maintaining the exploration sideline due to the characteristics of the moving means, and also in the control of the movement speed. Since it was almost impossible to maintain a constant velocity across the exploration line, it was unavoidable to include some error in the observed findings. In addition, if you want to create a map such as a flat topographic map for a certain area of the surveyed river based on the surveyed information, you can set up several exploration sidelines, acquire the topographical information along each of these sidelines, and then obtain the acquired cross-sectional information. Combining to create a riverbed topographic map, due to the error included in the cross-sectional information for each side line as described above, a significant error also occurs in the overall river topographic map.

On the other hand, in the conventional ground bed survey system using the GPR was placed on the boat and the exploration in mounting the GPR, in this case, there was a problem that the attenuation of the radio wave is inevitable by the bottom surface of the antenna. Also, to solve this problem, the antenna of GPR was mounted on a buoy or tube separately from the probe, but in this case, the GPR antenna needs to be approached as much as possible to the bottom surface in order to acquire a clearer bottom section. there was.

The present invention has been made to solve the problems of the prior art as described above, the present invention is equipped with a GPR and GPS in the riverbed ground survey system and by storing the information obtained from these GPR and GPS can be stored in association without error The purpose of this study is to provide a subsurface ground survey system that can obtain accurate survey results, and furthermore, it is possible to easily create more accurate and reliable river topographic maps by synthesizing the data obtained by observing each sideline.

In another aspect, the present invention is to provide a subsurface ground survey system that can obtain a more precise exploration results than the existing method by performing the exploration by locking the GPR antenna to a certain depth in the water.

1 is a perspective view showing the configuration of a bed soil survey system according to the present invention.

Fig. 2 is an elevational view showing the configuration of a bedbed ground investigation system according to the present invention.

Figure 3 is a perspective view showing a state in which the GPR transmission and reception radar waterproof in the present invention.

Figure 4 is an exploded perspective view showing a combined state of the GPR transmission and reception radar in the present invention.

5 is a block diagram showing the configuration of the information processing apparatus according to the present invention.

Fig. 6 is a diagram showing the positions of the exploration sidelines set in the rivers where the present invention was tested.

Fig. 7 is a cross-sectional view showing the bottom section extracted with the GPR data obtained in the test run of the present invention.

FIG. 8 is a cross-sectional view of each bottom side obtained by performing an exploration along the exploration side line of FIG. 6; FIG.

FIG. 9 is a bottom topographical map generated by arithmetic processing of the bottom-side cross-sectional view of FIG.

<Description of the symbols for the main parts of the drawings>

10: water moving means 20: underground exploration radar (GPR) device

22: control unit 24: transmit and receive antenna

30: GPS device 40: information processing device

51: horizontal pedestal 52: vertical holder

55: buoyancy offset material 56: rubber sheet

B10: data storage unit B20: topographic map generator

B30: map storage unit B40: output unit

The present invention provides a riverbed ground survey system for the ground exploration of the lower part of the river in order to achieve the above technical object, the water moving means that can move the upper surface of the river; A ground survey radar (GPR) device mounted on an upper portion of the water moving means and including a control unit and a transmission and reception radar; A GPS device mounted on an upper portion of the water moving means to calculate current position information; And an information processing device connected to the underground exploration radar device and the GPS device to exchange data.

In this case, the information processing apparatus includes a data storage unit for simultaneously storing the terrain information transmitted from the underground survey radar device and the location information transmitted from the GPS device; A map storage unit for storing an electronic map including location coordinates of rivers to be examined; A topographic map generator for generating a river topographic map by combining the data stored in the data storage unit and the electronic map stored in the map storage unit; And an output unit configured to output a river topographic map generated by the topographic map generator, wherein the topographic map generator compares the location coordinates included in the electronic map with the location information transmitted from the GPS device, and the corresponding topographic information. Is combined with the electronic map to generate a river topographical map.

Another technical feature of the present invention is to lock the GPR antenna to a certain depth in the water to perform the exploration so that a more accurate exploration result can be obtained than the conventional method. That is, in the past, the GPR antenna was installed on the top of the survey vessel or mounted on a separate buoy, but in this case, the GPR antenna was installed on the upper side from the surface of the water, and thus obtained by attenuation at the surface of the water, which is the boundary of the medium. There was a problem that the sharpness of the image was not satisfactory. In order to improve this, the present invention proposes a method of installing the GPR antenna to be locked to a certain depth in the water, and also provides a configuration of a specific system for this.

Hereinafter, with reference to the accompanying drawings will be described in more detail the present invention.

1 is a view showing the configuration of a bedrock ground survey system according to the present invention, referring to the drawing, the bedrock survey system of the present invention is a ground exploration radar (GPR) apparatus on the upper portion of the water moving means (10) It can be seen that the GPS device 30 is mounted, and the GPR and GPS are connected to an information processing device 40 such as a notebook computer to receive data from the GPR and GPS, and to process and store the data.

Of the above-mentioned components, the water moving means 10 is a moving means that can float and move on the upper portion of the river, for example, a conventional boat or a raft can be used. In this embodiment, as shown in Fig. 1, a boat is used so that an explorer can board and perform exploration.

The water moving means 10 is equipped with a ground probe radar (GPR; abbreviated as GPR in the present specification) and a GPS (Global Positioning System) device. The GPR device generates an electromagnetic wave of a predetermined frequency by a built-in pulse generator and receives the electromagnetic wave generated by the control unit 22 and the control unit 22 toward the lower portion of the river to receive the received electromagnetic wave reflected on the lower surface of the river. It comprises a transmitting and receiving antenna 24 for emitting and receiving the reflected wave reflected by the emitted electromagnetic wave reflected on the lower layer of the river.

The control unit 22 generates an electromagnetic wave having an arbitrary frequency by a user's operation, and the electromagnetic wave is radiated through the transmission unit Tx of the transmission / reception antenna 24. A part of the radiated electromagnetic wave is It is directly received by the receiver Rx or reflected by the river bottom and received by the receiver Rx again. The control unit 22 analyzes the intensity and arrival time of the electromagnetic wave thus received and transmits the analyzed data to the information processing apparatus 40 described later through the built-in signal output device.

The control unit 22 and the transmission / reception antenna 24 constituting the GPR device 20 may be mounted together on the upper portion of the water moving means 10 such as a boat, but the transmission / reception antenna 24 is disposed on the upper portion of the boat. In the case of installation, bar attenuation of the electromagnetic waves may be severely caused by the bottom surface of the boat, and the transmission / reception antenna 24 is preferably installed to be out of the water moving means 10. In addition, the transmission and reception antenna 24 may be installed to be submerged to a certain depth in the water to approach the bottom surface to obtain a more precise exploration result than the conventional method, the configuration for this is shown in Figures 1 and 2 It is. Referring to the drawings showing the configuration of a preferred embodiment according to the present invention, the water moving means 10 is provided with a horizontal pedestal 51 so as to protrude outward from the main body by a predetermined length and vertically downward from the horizontal pedestal 51. And a vertical holder 52 is installed so that an end thereof is submerged by a predetermined depth below the surface of the water, and the transmission and reception radar 24 is fixed by installing the transmission and reception radar 24 at the lower side of the vertical holder 52. The exploration can be carried out in a locked state to the bottom.

At this time, when performing the exploration by locking the transmission and reception radar 24 below the water as described above, it is necessary to waterproof the transmission and reception radar 24 to prevent the malfunction of the device due to moisture. In this embodiment, as shown in FIG. 3, a waterproof case 24 'that can accommodate the transmission and reception radar 24 is made of an impervious synthetic resin, and the gap of the coupling part is coked with a sealant S to transmit and receive radar. (24) is preventing contact with water.

In addition, since the buoyancy may occur due to the specific gravity of the waterproof case 24 'in the case configured as described above, it may be difficult for the boat to maintain a stable posture. In this case, the buoyancy offset material 55 having a predetermined weight may be used to offset the buoyancy. It is preferable to install more. In this embodiment, as shown in detail in FIG. 4, the buoyancy offset material 55 is made of a material such as stone and stacked on the upper surface of the transmission / reception antenna 24. At this time, a rubber plate 56 may be further provided between the buoyancy canceling material 55 and the transmission / reception antenna 24.

The GPS (Global Positioning System) device is a device for calculating the current position of the bedrock surveying system of the present invention by receiving data transmitted by the GPS satellites. The GPS device 30 uses a size small enough to be mounted on the water moving means of the present invention, and in this embodiment, a Pathfinder ProXP system manufactured by the US Trimble company is used. It consists of GPS and beacon integrated receiver and antenna, and has an accuracy of 50cm horizontal distance through real time error correction.

The information processing device 40 is connected to the GPR device and the GPS device. The information processing device 40 is a device having an information processing capability, such as a notebook computer, and simultaneously stores the digitized terrain information transmitted from the GPR device and the location information received from the GPR device as one information, The stored topographical map is automatically generated using the stored information. The configuration of the information processing apparatus 40 will be described in more detail with reference to the accompanying FIG. 5 as follows.

5 is a block diagram showing the configuration of the information processing apparatus 40 in the present invention. The information processing apparatus of the present invention is basically composed of a computer system capable of arithmetic processing and storage of input data and outputting the processed result. In particular, in the case of the riverbed ground survey system of the present invention, it is appropriate to use a notebook computer for easy portability and movement. Referring to FIG. 5, the information processing apparatus 40 according to the present invention includes a data storage unit B10 which receives data from a GPR and a GPS and stores them in association with each other; A map storage unit B30 in which a digitized electronic map of the river to be investigated is stored; A topographic map generator (B20) for generating a river topographic map by combining the data stored in the data storage unit (B10) and the electronic map stored in the map storage unit (B30); And, it can be seen that it is configured to include an output unit (B40) for outputting the generated river topographical map.

The data storage unit B10 functions to simultaneously store digitized terrain information transmitted from the GPR device 30 and location information transmitted from the GPS device 30 in association with each other. It becomes the basic material in the making of. In comparison with the conventional method, the bottom line section is extracted through the analysis process by continuously receiving the reflected wave from the GPR apparatus 20 by simply moving the probe line along the probe side line. To achieve this, the probe must maintain an accurate straight path along the sideline and at the same time maintain a constant travel speed. However, according to the present invention, since the bottom section information obtained by the GPR is combined with the exact position information obtained from the GPR apparatus 20, when the data is processed based on such position information, there is some sideline deviation in the operation of the survey vessel. Alternatively, accurate exploration results can be derived without maintaining a constant moving speed.

The map storage unit B30 is a storage device in which an electronic map of a river to be investigated is stored. The electronic map may be stored in a data file format in which the planar shape of the surveyed river is digitized. The electronic map may include location coordinates of the surveyed river to be compared with the position information input from the GPS. The map storage unit B30 may be implemented as an internal hard disk, a CD-ROM, or a floppy disk when using a notebook computer as an information processing device as in the present embodiment.

The topographic map generation unit B20 is a module which finally generates a bottom topographic map by combining data stored in the data storage unit B10 and an electronic map stored in the map storage unit B30. As shown in FIG. 5, the topographic map generator B20 receives data from the data storage B10 and the map storage B30, respectively, and calculates the topographical map by calculating the data. The location data obtained from the GPR is combined with the data transmitted from the) to compare the location information with the location coordinates included in the electronic map transmitted from the map storage unit B30, thereby creating a river topographic map. In the case of using a notebook computer as the information processing device as in the present embodiment, the CPU corresponds to this.

The output unit B40 is a module that receives the topographical map generated by the topographic map generator B20 and outputs the topographic map, and may be implemented as a liquid crystal display or a CRT monitor.

Next, a process of obtaining a bed soil cross-sectional view using the bed soil survey system according to the present invention and a process of preparing a bed topographic map using the same will be described.

First, in order to investigate the bottom ground structure of a river using the riverbed ground survey system according to the present invention, an exploration sideline to perform exploration in the surveyed river must be set in advance. When the exploration side line is set as described above, data are acquired while moving the ground investigation system of the present invention along the planned exploration side line. Figure 6 shows the position of the sideline set in the river in which the present invention was tested.

In acquiring data along the side lines set as described above, a GPS device that provides location information along with the operation of the GPR device should be operated. Normally, 7 pieces of GPR data are obtained per second, and GPS location information is obtained at 1 second intervals. In this embodiment, two types of data are synchronized by marking at the same time every 10 seconds, and 1 second interval (about 30 cm) is made through Fortran program. Digitized by.

On the other hand, in order to obtain the GPR cross-section, data must be acquired by continuously moving the exploration sideways in the horizontal direction. When the analysis process is performed, the intensity of the reflected wave in the horizontal axis representing the horizontal distance and the vertical axis representing the depth or time are displayed in color. You can get a bottom section like 7 Remarkable reflective surfaces such as bottom and bedrock layers appear as a continuous profile with a constant reflection intensity on the cross-sectional view, and these continuous profiles are converted into digitized files through a reflection surface extraction program, which is the basic data for creating topographic maps. Becomes The digital file includes the arrival time and intensity of the reflected wave, from which the distance to the reflective layer can be calculated, and the intensity provides clues to infer the type of deposit.

Fig. 7 (a) shows an example in which the bottom surface is extracted from the GPR data acquired in the test run, and is a reflected wave horizontal profile showing the extracted bottom surface topography. The bottom surface is a curved surface represented by the initial reflected wave, and the contrast represents the reflection intensity. The reflection surface extraction program reads the cross-sectional file as described above and generates the reflection time and intensity of the designated reflection wave as an ASCII file.

On the other hand, the present invention proposes a configuration to be installed so as to be locked to a certain depth in the water in the installation of the GPR transmission and reception antenna, according to this configuration, the transmission and reception antenna closer to the bottom surface, so the resolution of the extracted cross-sectional view You can expect an improvement. Fig. 7 (b) shows a cross-sectional view of the above-described underwater antenna using the underwater antenna and compares it with the result obtained without submerging the antenna shown in Fig. 7 (a). The immersion depth was 50 cm, and as can be seen from the drawings, the cross section obtained by immersing the antenna in water showed that the reflected wave from the bedrock was more clearly seen.

When the bottom cross-sectional file is obtained for each of the plurality of side lines set as described above, the bottom topographic map is generated by combining the bottom cross-sectional file with the electronic map including the plane information of the surveyed river. As described above, the present invention periodically receives the location information from the GPS device and combines it with the GPR data stored in the form of the digital file so that the GPR data obtained as a result of the exploration includes information on the horizontal position. In the present invention, when generating a river topographic map, the GPR data obtained for each sideline is combined with an electronic map displaying a planar shape of an irradiated stream and interpolated to create a river topographic map. At this time, the combination of the GPR data and the electronic map is made by comparing the position coordinates included in the electronic map with reference to the position information transmitted from the GPS device and combining the GPR information corresponding to the position with the electronic map. The topographic map generator of the information processing apparatus generates a topographic topographic map by connecting portions having the same depth with the electronic map combined with the GPR information in a contour line. FIG. 8 is a cross-sectional view of the riverbed obtained by performing the exploration along the side line of FIG. 6, and FIG. 9 illustrates a riverbed topographical map generated by arithmetic processing of the cross-sectional view of FIG.

When the bottom topographical map is generated as described above, it is output through the output device. In the case of a computer such as a notebook computer, this may be output in the form of image data through a liquid crystal display, or may be output through a device such as a printer, or may be converted into the form of a computer file and used in other programs.

According to the present invention described in detail above, it is possible to acquire accurate survey results without errors by mounting the GPR and GPS together and storing the information obtained from the GPR and the GPS together in the riverbed ground survey system, and further, each sideline In producing the topographical map by synthesizing the data obtained by observing each star, there is an effect of providing a bedside ground survey system that can easily create a more accurate and reliable topographical map.

In addition, according to the present invention, by performing the exploration by locking the GPR antenna to a certain depth in the water, there is also an effect of providing a subsurface ground survey system that can obtain a more precise exploration result than the conventional method.

Claims (5)

In the bed ground survey system for the ground exploration of the lower part of the river, Water moving means that can move the upper surface of the river; A ground exploration radar (GPR) device mounted on the water moving means and including a control unit and a transmission and reception radar; A GPS device mounted on the water moving unit to calculate current location information; And an information processing device connected to the underground survey radar device and the GPS device to exchange data. The information processing device, A data storage unit for simultaneously storing the terrain information transmitted from the underground survey radar device and the location information transmitted from the GPS device; A map storage unit for storing an electronic map including location coordinates of rivers to be examined; A topographic map generator for generating a river topographic map by combining the data stored in the data storage unit and the electronic map stored in the map storage unit; And, An output unit for outputting a river topographic map generated by the topographic map generator; Including, wherein the topographical map generation unit GPS and the location coordinates included in the electronic map and the location information transmitted from the GPS device, and combines the corresponding topographic information to the electronic map to generate a river topographical map Ground Soil Survey System using GPR and GPR. The bottom ground survey system using GPS and GPR according to claim 1, wherein the transmission and reception radar of the underground survey radar is waterproof and is fixed to the water moving means so as to be locked to a predetermined depth below the water surface. The apparatus of claim 2, wherein the water moving unit further comprises: a horizontal pedestal protruding outwardly from the main body by a predetermined length; and a vertical pedestal extending vertically downward from the horizontal pedestal so that the end portion is locked to a predetermined depth below the surface of the water. Transmitting and receiving radar is a bottom ground survey system using GPS and GPR, characterized in that fixed to the lower side of the vertical holder. [4] The bed ground survey system using GPS and GPR, wherein the buoyancy offset material having a predetermined weight for buoyancy offset is installed in the transmission and reception radar. [5] The bottom ground survey system using GPS and GPR of claim 4, wherein the buoyancy offset material is laminated on the upper surface of the transmission and reception radar as a plate member.