KR102002904B1 - Structure deformation early monitoring system using radar and reflectors - Google Patents

Abstract

It is an object of the present invention to provide a structure deformation detection system capable of continuously monitoring a deformation state of a structure without direct measurement by a person.
In addition, it is an object of the present invention to provide a structure of a structure for detecting a deformation of a structure as described above, which is less likely to be influenced by a sensor itself, It is also to do.
According to the present invention, in order to measure the deformation of the outside of the structure, that is, the surface of the structure in real time, a plurality of radio wave reflectors are attached to the surface of the structure and a radio wave radar capable of detecting the attached reflector is installed. It is possible to digitize measured data by measuring distances, angles, and reflectances, build and store them in a database, and then analyze the amount of data continuously for initial data to determine the deformation of the structure. . In other words, by using radar and reflector, the degree of change of the structure surface can be analyzed in real time.

Description

[0001] STRUCTURE DEFORMATION EARLY MONITORING SYSTEM USING RADAR AND REFLECTORS [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for detecting a change in shape of various structures such as a cutout, a building, a road, a bridge, a tunnel,

The structure is deformed by the use load over time. Since such deformation continues to accumulate, it can lead to the collapse of the structure, so measuring the deformation of the structure is a very important basis for judging the condition of the structure. In the past, in measuring the degree of deformation of the structure, the stability of the structure was evaluated by measuring the deformation in the horizontal direction and the vertical direction by the measurement. However, existing methods have the inconvenience that people should carry out surveying in the field on a regular basis. In addition, since the surface of the structure is mostly exposed to the outside, there is a problem that the measurement is difficult when the weather condition is poor. In addition to the fact that the safety of the surveyor can not be guaranteed, the error of surveying has also become a problem, and it is impossible to measure by minute or hour by human measurement.

In addition, it is difficult to immediately measure the deformation of the structure because it is more difficult to measure the place where the human activity is not smooth in the structure, and it is difficult to measure the deformation in real time. . Therefore, it is necessary to develop a technology that can precisely measure the deformation of a structure in real time in a simpler and easier way.

Korean Patent Publication No. 10-2014-0128508 discloses a slope deformation detection system using an optical fiber. However, due to difficulties in construction and due to the external environment such as snow, rain, wind, etc., There is a problem that an error occurs.

Therefore, an object of the present invention is to provide a structure deformation detection system capable of continuously detecting a deformation state of a structure without direct measurement by a person.

In addition, the object of the present invention is to provide a structure deformation detection system as described above, in which the sensor itself is less influenced due to a change in weather or the like, thereby reducing the measurement error, And the like.

According to the present invention, in order to measure the deformation of the outside of the structure, that is, the surface of the structure in real time, a plurality of electromagnetic wave reflectors are attached to the surface of the structure, and an electromagnetic wave radar capable of detecting the attached reflector is installed. The angle of the reflection, and the reflection amount of the data, converts the measured data into digital data, constructs it as a database, stores the data, and then analyzes the data of the initial data continuously to determine the deformation of the structure A structure deformation detection system is provided. In other words, by using radar and reflector, the degree of change of the structure surface can be analyzed in real time.

In addition, with video surveillance, which allows people to visually confirm with the radar, the surface of the structure and the reflector can be monitored by the image.

In addition, a video surveillance system including a database by a radar is built as an app, allowing an administrator to easily grasp the situation with a mobile terminal.

The app includes a system for alerting a structure manager, an upper manager, and related organizations in real time to prevent a safety accident of a structure when the degree of deformation exceeds a predetermined level based on information analyzed in real time.

That is,

A reflector for reflecting radio waves;

A radar that transmits a radio wave to the reflector and receives a reflected wave reflected by the reflector; And

And a computer connected to the radar for constructing information on the reflected wave signal reflected from the reflector in a database and continuously updating the reflected wave signal,

Fixing at least one reflector on a surface of a structure to be monitored,

By placing the radar at a point where it can transmit and receive radio waves to the reflectors,

Receiving at least one of a reflection angle, a reflection amount of reflected waves received from the reflectors at a specific time point, and a position of the reflector from the reference point, from the radar,

Continuously receiving one or more data from the reflectors, the reflection angle, the reflection amount, or the position of the reflector from the reference point, and comparing the analyzed data with the initial data while updating the database.

In the above, the distance to the reflector is determined by the reflection from the reflector using one or more methods of mass algorithm, centroid, interpolation to obtain a resolution that is finer than the distance resolution determined by the system specification of the radar. And estimating the frequency of the reflected wave to obtain a precise result value.

In the above, a video camera is further provided together with a radar to monitor the shape of the structure as an image.

In the above, the shape of the reflector may be a sphere, a cylinder, a flat plate, a corners in which flat plates are folded, an open tetrahedron having concave portions formed by connecting three triangles, an open polyhedron having concave portions formed by connecting three rectangles, An opening-shaped curved body having a concave portion, or a polyhedron having an opening portion.

In the above structure, a threshold is set for each of at least one data type from the observed reflection angle, the reflection amount, or the reflector position from the reference point, and a warning message is generated in the computer when the variation amount of each data reaches a threshold value. to provide.

The structure shape monitoring system according to the present invention is characterized in that data is managed for each reflector in the database constructed by grasping the positional information with respect to each of a plurality of reflectors at a specific time by a radar.

In this case, the plurality of reflectors are collectively collected at the same time with the data of the reflectors in the database constructed by grasping the positional information by the radar at a specific time, and the overall trend of the observed structure is ascertained A structure shape monitoring system is provided.

Also, the surveillance system can be constructed as an app, and the administrator can access the surveillance system using the mobile terminal.

Further, according to the present invention,

A radar that transmits a radio wave and receives a reflected wave reflected by the reflector; And

And a computer connected to the radar for constructing information on the reflected wave signal reflected from the reflector in a database and continuously updating the reflected wave signal,

The radar is installed on the water surface so as to measure the water level of the water,

* The reflector is the water surface,

And the water level can be continuously measured by measuring the distance between the point where the radar is installed and the water surface through the reflected wave reflected by the water surface by the radar.

In the above, the distance to the surface of the water is determined by the mass algorithm, the centroid, the interpolation (the interpolation), the frequency of the reflected wave reflected from the water surface in order to obtain a finer resolution than the distance resolution determined by the system specification of the radar interpolation to estimate the frequency of the reflected wave reflected from the water surface to obtain a precise result value.

In the above, a distance value corresponding to a frequency obtained through frequency estimation is stored for a predetermined time to generate a histogram, and a probability distribution represented by the histogram is checked to determine a distance having the highest frequency as a water level value And provides a surveying system.

In the above, the radar analyzes the water level at a plurality of points, analyzes the water level between points at the same time point, and analyzes the water level change between the points in a time-series manner to grasp the wave height.

In the above, a threshold value of the water level or the water level change amount is set, and a warning is issued when the water level or the water level change amount is measured.

A water level management system is provided in which a plurality of water level surveying systems are installed in one or more rivers and managed by a network to predict a flood.

Also, the water level management system can be constructed as an application, and the administrator can access the water level management system using the mobile terminal.

In the above,

Wherein the radar is provided with an outer cover having a slope to prevent foreign matter from accumulating, and the outer cover is made of a dielectric material that is not metallic. do.

The present invention provides a structure shape monitoring system, wherein the outer cover is filled with hot wire to melt snow.

In this case, the monitoring target structure includes a building exterior monitoring system including a building exterior wall, a cutout, a road construction site or a subway construction facility, a facility for water pipe filling, a facility for inserting a wire, and a building material piled up.

The radar has the advantage of using radio waves to sense the structure regardless of the surroundings, the snow, the rain, the wind, the fog, the daytime, and the nighttime when the surface of the structure is exposed to the outside. The reflector attaches to the surface of the structure. Even if the radar detects the structure and the reflector, the reflection characteristic inherent to the reflector can distinguish the structure from the reflector.

FIG. 1 is a schematic view showing an example in which a structure deformation sensing system according to the present invention is constructed on an inclined plane.
Fig. 2 is a view for explaining the reflectance different from that of the reflector in structure and shape.
3 is a schematic diagram illustrating the configuration and function of the radar.
4 to 6 are views illustrating functions of an app screen constructed by combining a video surveillance system and a radar-reflector system.
FIG. 7 shows an example (top) in which the radar is installed so as to face the incision in front, and an example in which the incision is installed so as to observe the incision in an oblique direction.
FIG. 8 shows that an example of frequency estimation can improve the accuracy by finding the center of gravity of a frequency peak or interpolating it.
Fig. 9 shows the radar 200 covered with the cover 250. Fig.
FIG. 10 is a flowchart showing an example of the present invention.
11 illustrates application of the reflector-radar control system of the present invention to building detection.
12 shows a state in which the height of a water surface is measured by a radar according to the present invention.
13 is a histogram of data stored during a certain time in the process of calculating the water level in real time.

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

FIG. 1 shows an example of a system for detecting the shape of a cutout by attaching reflectors to a cut slope according to the present invention and combining a radar and a digital video camera. That is, a plurality of reflectors, which reflect the electromagnetic waves to continuously detect the shape of the cutouts, are distributed to the radar on the incision slope surface, and the distance from the reflector and the reference point (which may be the radar position) And the position (bearing), and set a threshold value for each physical quantity. If it is out of this range, a warning message will be displayed so that the person can inspect it directly or take practical measures such as civil works. That is, the monitored structure can be applied to an exterior wall of a building, a cut-out point, a road construction site or a subway construction site facility, a waterway pipeline landfill facility, a cable landfill facility, and a piled building material. It can be installed on site to influence the location or shape of the terrain or structure to warn of the risk.

That is, in this embodiment, as in the case of a landslide warning system, a reflector is installed on various objects requiring observation of changes in position / shape and is monitored in real time by a radar to observe a shape change.

To this end, a number of reflectors should be attached to the structure to be detected. The shape of the reflector can be variously configured as needed.

The shape of the reflector 100 can be made variously.

Fig. 2 shows various shapes of the reflector and the corresponding reflective surface area. Since the reflection amount of the electromagnetic wave is changed according to the shape of the reflector, the reflector 100 is installed and then the physical quantity such as the initial reflection amount of electromagnetic waves is measured to construct a database. The shape of the reflector 100 may be any shape such as a sphere, a cylinder, a flat plate, a corners in which flat plates are folded, an open tetrahedron having concave portions formed by connecting three triangles, an open polyhedron having concave portions formed by connecting three rectangles, An open curved body having three concave portions, a polyhedron having an open portion, and the like. That is, the structure can be selectively constructed depending on whether the surface of the structure is a curved surface, a slant surface, or a flat surface.

2 shows a reflector 100 in which a bar 120 is connected to a vertex of an open tetrahedron 110. FIG. The reflector 100 may be attached to the inclined surface with a substantially uniform distribution. The attaching method may be to attach the reflector to the surface of the structure using an adhesive such as cement. It is also possible to place the reflector with the rod in the soil using a rod. It is also possible to construct the wall of the building, the joints of the legs and the fragile parts of other structures while installing the reflector at the time of construction.

The electromagnetic wave is totally reflected when it is incident on the conductor. By using this property, it is possible to shield the electromagnetic wave with a conductor or send the electromagnetic wave in a specific direction like a reflection plate.

The principle of reflection of electromagnetic waves on conductors can be seen as reproduction rather than reflection. Almost all the energy is instantaneously changed into the surface current of the conductor while the electromagnetic wave touches the conductor which transmits electricity well. As a result, suddenly generated surface currents produce electromagnetic waves of the same angle as the incident angle. It should be noted that the principle of electromagnetic wave generation itself is a change in current. In this process, a slight loss occurs depending on the loss component caused by the conductor, that is, the conductivity. Observing the electromagnetic wave reflection angle by the reflector in consideration of the reflection phenomenon by the conductor, the change of the reflector shape can be seen. This can be judged by the change of the reflector fixed to the structure by the change of the shape of the structure. It is possible to observe not only the reflection angle of the reflector but also the reflection amount and the distance data together to grasp the change state more clearly.

The radar receives the electromagnetic waves transmitted to and from the individual reflectors, and the computer connected to the radar continuously compares the received signals with the initial database to detect changes in the shape of the structures.

If n reflectors are installed on a structure, the radar recognizes the position of each reflector, such as the distance to each reflector and the azimuth angle, so that each reflector can be distinguished. Therefore, And then analyzes and analyzes the change of the reflection signal.

On the other hand, there is no clear confirmation to monitor the structure by only information by radar.

Accordingly, in this embodiment, a digital video camera is installed together with a radar so that images of the structure can be observed even with images. In other words, by installing a video camera together with a radar and looking at the direction in which the radar looks, it is possible to intuitively determine the occurrence of a problem by continuously receiving the image of the structure and observing the image with the data analysis result by the radar , It is possible to check the image first and dispatch the workforce when a problem occurs.

A video surveillance system using radar and video camera can be implemented as an app by building a website using a computer server. As a result, a manager having a terminal such as a smart phone can conveniently monitor the structure.

The summary of the implementation of this embodiment is summarized as follows.

Attach a number of reflectors to the surface of the structure

② Detect multiple reflectors on the surface of the structure using radar

③ Set the initial detection standard based on the detected reflector distance, angle, and reflection

④ Using the radar to continuously measure the distance, angle and reflection of the reflector

⑤ Accumulate the measured data and process the data using the standard deviation algorithm

⑥ Analyze the change of the reflector by comparing the initial detection standard with the processed data

⑦ If the change of the reflector exceeds the set value, it is judged that the structure is deformed.

⑧ Structural supervisor confirms reflector variation and image sensing data and takes action to prevent safety accidents

Fig. 3 shows a schematic diagram for helping to understand the function of the radar.

In this embodiment, the radar is installed at a position where the reflectors attached to the structure can be monitored to monitor the shape of the structure. Radar has the advantage of collecting reliable data even in nighttime, weather conditions such as heavy snow, heavy rain, and fog. This is an advantage in that information on the structures can be accurately collected when an environment where a dangerous situation may occur may occur, thereby enabling a safe evacuation measure to be promptly issued.

The digital video camera used in this example and its video surveillance are shown in Fig.

A digital video camera is a camera that can detect images using electronic sensors without film and store the captured image information in digital movie file formats such as MPEG, DV, and MJPEG. Conventional cameras divide an image into bitmaps and record each luminance as digital data, while storing images as analog data. After taking a picture, you can connect to an external computer to transfer the image, and you can easily edit, modify, and print it with your computer.

FIG. 5 shows an example of a central manager computer screen for detecting regions where reflectors and radar are installed nationwide by a sensing system constructed as a network so that images can be simultaneously detected. A thumbnail image for each region is displayed along with a map, and a specific thumbnail can be clicked to view the enlarged image.

FIG. 6 shows a scene in which an administrator builds an application and observes with a smartphone.

FIG. 7 shows an example (top) in which the radar is installed so as to face the incision in front, and an example in which the incision is installed so as to observe the incision in an oblique direction. The radar installation point is selected to be appropriate for the surrounding environment, and the position of one reflector is selected as a reference point within the cutout. One or more radar may be installed for one incision.

The limits of the location of the reflectors are determined by the distance resolution according to the bandwidth of the radar frequency in the radial direction with respect to the plane direction viewed by the radar and by the distance resolution along the azimuth direction, is determined by the angular resolution according to the beamwidth by the aperture. For reliable detection, it is desirable to provide reflectors at positions corresponding to at least twice the bandwidth and beam width, at least corresponding to distance / angle resolution in each direction.

And are collected / managed by the positions of the reflectors with respect to the physical quantities measured by the radar. At this time, the position of the reflector can be managed by converting from (r,?) To (x, y).

The distance resolution of the radar is determined by the bandwidth. For example, in the case of the 24GHz ISM band, a bandwidth of less than 200MHz can be used, and the distance accuracy is 0.75m, which is not suitable as a sensor for landslide alarm . In order to overcome this ambiguity, frequency estimation is used in the frequency domain. FIG. 8 shows that an example of frequency estimation can improve the accuracy by finding the center of gravity of a frequency peak or interpolating it. Other mass algorithms, centroid methods can be applied.

When extracting the angle information of the reflector through the radar, the accuracy becomes higher as the angle unit of the steering vector becomes smaller in the conventional conventional beamforming algorithm. If the angular unit is too small, the required memory is very large and the calculation amount is large. Therefore, when the angle unit is set to be larger than the required level, the accuracy can be improved by estimating the angular power spectrum like frequency estimation.

In addition, by dividing the angle estimation into two or more steps and finding the coarse peak by setting the initial angle unit to be large, and dividing the angle around the corresponding peak finely, it is possible to obtain an accurate result . For example, in the first step, the angular unit is 1, the peak is calculated, and the angle estimation is performed in the unit of 0.1 degree around the peak. If higher precision is required, repeat it in smaller angular increments.

In addition to the basic angular estimation algorithm, high-resolution algorithms (MUSIC, ESPRIT, Maximum Likelihood) can be used to increase the angular accuracy.

For each of a number of reflectors, physical quantities such as individual locations, reflectances, and / or reflectance angles are stored in the database, and statistical values for the entire terrain are generated and stored in the database. These data are continuously updated in minutes, hours, days, and months, and statistically processed data is also updated in a time series, including quantities such as mean, variance, and standard deviation. On the other hand, since the terrain data about the reflector peripheral portion can be collected in addition to the physical quantity by the reflector, they are limited to a certain radius based on the reflector, and peripheral data is collected as a reference database.

Also, by analyzing the measurement values by connecting the physical quantities of the respective reflectors at the same time for each location, it is possible to grasp the overall change in the shape of the entire terrain or the structure. Statistics include temporal statistics of individual reflectors, local statistics at the same time.

Fig. 9 shows the radar 200 covered with the cover 250. Fig. The radar includes an outer cover 250 which is installed at a specific height or higher to prevent damage by nearby animals and the like and has a slope so that snow or rainwater does not accumulate. The material of the outer cover is a dielectric material that is not metallic but has low reflectance of electromagnetic waves.

In areas with high snowfall, heat can be embedded in the outer cover to allow snow to melt.

FIG. 10 is a flowchart showing an example of the present invention.

11 and 12 show application of the reflector-radar control system of the present invention to the building detection and the sleep detection, respectively.

The radar-based control / detection system can be used to alert the user of danger by installing in a site where changes in the location or shape of the terrain or structure, such as the subway construction site, waterworks piping construction site, have.

 In the embodiment of FIG. 11, a reflector is installed on a target object requiring observation of change of position / shape and a real time sensing is performed by a radar to observe a physical quantity change through a reflector, and an alert is issued when the change amount becomes a certain level or more.

Fig. 12 shows the detection of a water level change using a radar.

In the case of water level surveying, there is a problem that it is impossible to survey in bad weather including error, and difficult to measure in minute unit of time.

Therefore, radar is applied as a control system for this level survey.

As shown in FIG. 12, when the radar is installed at the same place as the bridge and the reflected wave reflected from the water surface is observed, the water level can be continuously measured. Since water itself is a conductor that reflects electromagnetic waves, it does not require a separate reflector. Just by installing a radar, you can measure the water level more accurately than by conventional cameras. That is, the radar can be used to send and receive electromagnetic waves to the water surface, extract distance information, and measure the water level. This water level measurement has stable detection performance even in bad weather such as fog, snow, rain, etc., so it can always measure stable water level. .

When the height of the water surface changes due to the wind, it is possible to accurately measure the height of the water surface and provide information about the depth of the water surface.

In addition, information can be provided by calculating the amount of change not only at the current water level but also at a desired time unit, and can warn a dangerous situation when the water level variation rapidly changes.

Due to the nature of the radar, the distance accuracy is inversely proportional to the frequency bandwidth, so the bandwidth must be wide for precise measurements. However, when bandwidth can not be widely used due to frequency regulation, the present invention can increase the frequency accuracy by using the frequency estimation technique and increase the accuracy of the distance (water level) calculated through the extracted frequency.

For example, if the bandwidth is 200MHz, the distance accuracy is 0.75m

It is not suitable for water level measurement but it can be measured in several centimeters through the proposed method.

As shown in FIG. 8, if the distance to the water surface is obtained through extraction of the frequency peak, the distance accuracy is not precise due to the limitation of the frequency bandwidth and the resolution of the FFT, but the accuracy can be improved by frequency estimation. The method of frequency estimation can be determined in various ways such as mass algorithm, centroid, and interpolation.

Even though the frequency estimation improves the distance accuracy for each scan cycle, the distance information of the moment may change due to the fluctuation due to the characteristics of the radar. For this reason, in the process of calculating the water level in real time, if the histogram is made by storing the data of the past specific time, the probability distribution of the water level can be obtained and more accurate water level measurement reflecting the statistical characteristics is possible (refer to FIG.

In addition, by storing the data for a specific time in the past and calculating the standard deviation, it is possible to extract wave and tide information from the water surface. In other words, if you draw a histogram by linking the water level of a certain point to the water level of an adjacent point, you can grasp the wave height.

These water level measurement systems can be installed in various places in rivers and they can be managed by a network. It is possible to install flood forecasting by integrating information gathered from the water level measurement system of each stream and installing a server, and installing a water level measurement system in a plurality of streams, can do. In the water level control system, if necessary, the installation of the radar can be implemented as an application and can be managed by a mobile terminal.

In this way, it is possible to implement a radar-reflector structure deformation detection system capable of continuously monitoring the structure and the water level management all over the world.

It is to be understood that the invention is not limited to the example described above and that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims. It is obvious.

100: reflector
110: Open tetrahedron
120: Rod
200: Radar
250: cover

Claims (1)

A plurality of reflectors disposed on a surface of a structure to be monitored and reflecting a radio wave; And
A plurality of reflectors for receiving reflected waves reflected from the plurality of reflectors,
Lt; / RTI >
Information about reflected waves reflected from the plurality of reflectors through the radar is built in a database,
The limit of the installation position is determined based on the distance direction and the angle direction with respect to the plane direction in which the plurality of reflectors are viewed by one radar,
The position information on the plurality of reflectors provided within the limits of the installation position is determined by grasping the distance and the angle to each of the reflectors by the one radar at a specific point in time,
The distance direction is determined by the distance resolution according to the bandwidth of the radar frequency of use,
The angular direction is determined by the angular resolution depending on the beam width by the antenna aperture,
The angle unit of the first step is set to be larger than the angle unit of the second step so that a coarse peak is found first and then an angle Is divided into small units to perform angle estimation around the peak.

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