JP3708514B2 - Slope monitoring system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a slope monitoring system for monitoring the state of a slope such as a slope based on GPS observation values, and more particularly to a GPS receiver used in such a slope monitoring system.
[0002]
[Prior art]
In general, slopes such as slopes, especially large-scale slopes with unstable elements, must always be properly maintained because of the danger of collapsing. Work and countermeasure work are performed. However, when maintaining slopes, there are still many unclear points about how the factors such as weathering of natural ground, transition of vegetation, and aging of protective works and countermeasures are involved in slope collapse. For this reason, the state of the slope is constantly monitored to predict the collapse of the slope in advance.
[0003]
By the way, conventionally, when performing positioning using GPS, navigation data radio wave information of GPS satellites that the GPS receiver was able to receive in advance is stored in advance, and navigation data radio waves of the GPS satellites that were previously received are dependent on the surrounding environment. When blocked, the measurement distance of the predetermined object is estimated based on the stored navigation radio wave data information, the previously received GPS satellites can be used, and the number of GPS satellites necessary for detecting the position of the predetermined object A method is known in which the position detection calculation of a predetermined object is performed by securing the position.
[0004]
In this method, for example, the state in which the PRN code can be controlled synchronously is determined as being received, and at the timing when the GPS receiver performs position detection, the state of each GPS satellite is determined to be in reception. For example, the distance is determined in the distance measurement from the GPS satellite to the GPS receiver, and the received GPS satellite is determined to be usable.
[0005]
On the other hand, for GPS satellites determined to be unusable, the period during which the navigation data of the satellite was received is continuous for a fixed time (for example, 10 minutes), and the variation rate of the measurement distance during that period is the limit value. When it is within (for example, 10 m / second), it is determined that the measurement distance can be estimated for 2 seconds from the time when it becomes unusable due to interruption, etc. If it is determined that it can be used, the measurement distance is estimated based on the amount of change in the PRN code. If it is determined that the GPS satellite cannot be used, the GPS satellite remains unusable after the determination until reception is possible (see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Laid-Open Patent Publication No. 9-133652 (paragraphs (0014) to (0016), FIG. 1)
[0007]
When trying to monitor the state of the slope using such GPS positioning, the displacement of the relative position between the reference point and the observation point is measured, and the slope of the slope is determined according to the measurement data (observation data). Although the condition is monitored, it is extremely difficult to evaluate the observation data itself because it is necessary to detect even a small displacement when monitoring the condition of the slope, and the observation data depends on external factors such as the weather. In view of the variation, it is difficult to accurately obtain the displacement of the relative position between the reference point and the observation point from the observation data without specialized knowledge.
[0008]
On the other hand, on slopes such as slopes, trees are often prosperous, and supports such as electric wires are sometimes installed. These trees and electric wire supports may become radio wave shields and may not receive radio waves well from GPS satellites. In other words, if GPS radio waves from GPS satellites that are visible and hidden with respect to the low-elevation GPS satellites and radio wave shields when viewed from the GPS receiver are included in the GPS positioning (for example, baseline analysis), It is difficult to determine the displacement of the relative position with respect to the observation point.
[0009]
[Problems to be solved by the invention]
By the way, in the method described in Patent Document 1, navigation data radio wave information of GPS satellites that the GPS receiver was able to receive in advance is stored in advance, and navigation data radio waves of the GPS satellites that were previously received are blocked by the surrounding environment. When this is done, the measurement distance of the predetermined object is estimated based on the stored navigation radio wave data information so that GPS satellites that have been received before can be used. When the slope displacement is monitored, the displacement of the relative position between the reference point and the observation point (that is, the displacement of the slope) is taken into consideration when monitoring the displacement of the slope. ) Cannot be monitored accurately.
[0010]
In other words, when the displacement of the slope is monitored, the displacement is extremely small, and there is a problem that it is difficult to accurately measure the displacement of the slope depending on the estimation of the measurement distance.
[0011]
An object of the present invention is to provide a slope monitoring system that can accurately monitor the state of a slope even when a radio wave shield is present.
[0012]
[Means for Solving the Problems]
According to the present invention, a GPS reference station that is used when monitoring the state of a slope, is disposed at a position outside the slope, receives a radio wave from a GPS satellite, and outputs the radio wave as reference GPS data; And at least one GPS station that receives radio waves from the GPS satellites and outputs the radio waves as GPS data, and the reference GPS data and a reference that indicates the position of the GPS reference station determined by the GPS data. A monitoring center that obtains the displacement of the slope based on the point location information and the location information indicating the position of the GPS station and uses it as slope displacement data, and each of the GPS reference station and the GPS station has a sky direction. with imaging the surroundings as elevation angle 90 °, an imaging means for obtaining image information is added which indicates a 16 orientation, the monitoring center , The determination whether the radio wave shield for shielding the GPS radio wave from an image obtained by the imaging means is present, the position of the radio wave shield picture whose recognized image and Telecommunications shield as a mask position , Comprising a mask coordinate generating means for generating mask coordinates at a pitch of a predetermined elevation angle in 16 azimuth coordinates with the sky direction as an elevation angle of 90 °, and the monitoring center includes the GPS reference station and the GPS station in the mask coordinates. A slope monitoring system characterized by using the GPS radio wave arriving from the direction of the mask position as a prohibited radio wave and using the reference point position information and the position information according to other GPS radio waves excluding the prohibited radio wave is obtained. It is done.
[0013]
In this way, the position of the radio wave shielding object that blocks the GPS radio wave at the pitch of the predetermined elevation angle on the coordinates indicating the 16 azimuths with the sky direction in each of the GPS reference station and the GPS station at the monitoring center is set as the mask position. Set the specified mask coordinates, and use GPS radio waves coming from the mask position direction in the mask coordinates for each GPS reference station and GPS stations as prohibited radio waves, and reference point position information according to other GPS radio waves excluding the prohibited radio waves, and If the slope displacement data is generated using the position information, the state of the slope can be accurately monitored even if a radio wave shield or the like is present.
[0014]
Further, in the present invention, each of the GPS reference station and the GPS station is provided with imaging means for capturing an image of the surroundings with the sky direction as an elevation angle of 90 ° and obtaining an image to which information indicating 16 directions is added , In the monitoring center, it is determined whether or not there is a radio wave shielding object that shields the GPS radio wave from the image obtained by the imaging means, and the position of the radio wave shielding object image in the image recognized as the radio wave shielding object Is a mask coordinate generating means for generating mask coordinates at a pitch of a predetermined elevation angle in 16 azimuth coordinates with the sky direction as an elevation angle of 90 ° .
[0015]
In this way, each of the GPS reference station and the GPS station captures an image of the surroundings with the sky direction as an elevation angle of 90 °, obtains an image, recognizes the position of the radio wave shielding object from this image, and specifies the mask position. If the coordinates are generated, the mask coordinates can be updated as necessary.
[0016]
The GPS reference station and the GPS station are preferably connected to the monitoring center via a network. In this way, a plurality of slopes can be collectively monitored at the monitoring center.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. In the following description, the shape, dimensions, and the like are not limited to these unless otherwise specifically described.
[0018]
Referring to FIG. 1, first, the illustrated slope monitoring system includes a plurality of slope monitoring apparatuses 11-1 to 11-N (N is an integer of 2 or more), and these slope monitoring apparatuses 11-1 to 11-11. -N is connected to the monitoring center 12 via a wired communication line 13 such as an optical cable communication line, for example. The slope monitoring devices 11-1 to 11-N are arranged on different slopes, monitor and measure the state of each slope, and send the data to the monitoring center 12 as observation data (measurement data). Here, the observation data transmitted by the slope monitoring devices 11-1 to 11-N are referred to as first to Nth observation data, respectively.
[0019]
The monitoring center 12 is provided with a computer system 12a, an output device (monitor) 12b such as a display device, an input device 12c, and a database 12d. In accordance with the first to Nth observation data obtained from the slope monitoring devices 11-1 to 11-N, slope displacement data is generated for each slope as described later. In addition, the monitoring center 12 is arrange | positioned in the point distant from the slope monitoring apparatuses 11-1 to 11-N, and collects these observation data remotely.
[0020]
The slope monitoring device (GPS measuring device) 11-n (where n is any number from 1 to N) includes at least two GPS (Global Positioning System) receivers (measuring devices). Then, it has GPS receiver 11a-11c. One of these, for example, the GPS receiver 11a is arranged as a reference point receiver (GPS reference station) at a point (reference point) other than the slope. That is, the reference point receiver 11a is disposed on the stable ground away from the slope.
[0021]
On the other hand, the other GPS receivers 11b and 11c are disposed on the slope (at least one GPS receiver is disposed on the slope). The GPS receivers 11a to 11c receive radio waves (GPS radio waves) from at least four GPS satellites at preset time intervals, and output GPS data as observation data at each time interval. The time interval is set by an observation time setting command from the computer system 12a, for example.
[0022]
These GPS receivers 11 a to 11 c are connected to a communication aggregator 11 d or a wireless aggregator 11 e used as a communication device, and the communication aggregator 11 d is connected to a wired communication line 13. Then, the communication concentrator 11 d sends each observation data to the monitoring center 12 via the wired communication line 13.
[0023]
In addition, the wireless aggregation device 11e sends each observation data to the wireless relay device 16 via a wireless line. FIG. 1 shows one radio repeater 16, but actually, a plurality of radio repeaters 16 are arranged, and a communication area is defined for each radio repeater 16. Observation data is received from the wireless aggregator 11e located in the communication area. The wireless repeater 16 is connected to the wired communication line 13 described above, and observation data for each slope is sent from the wireless repeater 16 to the monitoring center 12. Each observation data is added with information for identifying the GPS receiver (GPS receiver identification information).
[0024]
Here, paying attention to the GPS receiver 11a, the GPS receiver 11a is provided with a digital camera (not shown). For example, a fisheye lens is attached to the digital camera, and the central axis of the fisheye lens is the sky. It is oriented in the direction (vertical direction). And the image imaged with the digital camera is sent to a monitoring center like observation data. On the other hand, in addition to the function of calculating slope displacement data, the computer system 12a includes a positioning calculation unit 23, an image processing unit 24, a mask coordinate setting unit 25, and a storage unit 26 as shown in FIG. . The GPS receivers 11b and 11c are configured in the same manner as the GPS receiver 11a. That is, a digital camera is provided.
[0025]
When the GPS receiver 11a is installed at a reference point, the sky direction is imaged by a digital camera in accordance with an imaging command from the monitoring center 12, and image data (digital image) is obtained. As described above, since the fisheye lens is attached to the digital camera, it is possible to capture an image up to almost the horizon (that is, an elevation angle of 0 °) when the sky direction is an elevation angle of 90 °. The digital image thus obtained is sent to a monitoring center (computer system) and given to the image processing unit 24. Then, the image processing unit 24 determines whether or not a radio wave shielding object exists according to the digital image (binary image). That is, the image processing unit 24 recognizes radio wave shielding objects such as trees, electric wires, their supporting objects, and buildings using a template matching technique, and generates a processed image showing only the radio wave shielding objects. At this time, the image processing unit 24 sets 16 orientations for the processed image. The 16 orientations are preset in the digital camera, and information indicating the 16 orientations is added to the digital image.
[0026]
The processed image obtained in this way is given to the mask coordinate setting unit 25. The mask coordinate setting unit 25 sets mask coordinates according to the processed image. That is, assuming that the sky direction is an elevation angle of 90 °, for example, at a pitch of 16 azimuths × 1 ° elevation angle, the position of the radio wave shielding object image corresponds to the radio wave shielding object image in the processed image, and the sky direction is the elevation angle. Set coordinates to be 90 ° (set mask coordinates).
[0027]
For example, the mask coordinate setting unit 25 sets the mask coordinates shown in FIG. In this mask coordinate, as shown in the figure, the position of the radio wave shielding object image is the mask position 31 (indicated by hatching in the figure), and the pitch is 16 azimuth × 1 ° elevation angle in 16 azimuth coordinates with the sky direction as the elevation angle 90 °. Is set in The mask coordinates are stored in the storage unit 26. Such mask coordinates are also set for the GPS receivers 11b and 11c. These mask coordinates may be displayed on the monitor.
[0028]
In the monitoring center 12 (computer system 12a), positioning is performed according to GPS radio waves from GPS satellites (not shown) received by the respective GPS receivers. In performing positioning, the computer system 12a stores the storage unit 26. Then, the mask coordinates are read out, and GPS radio waves excluding the prohibited radio waves are used as radio waves arriving from the mask position direction of the mask coordinates. That is, the positioning calculation unit 23 performs positioning using received GPS radio waves excluding prohibited radio waves.
[0029]
The positioning calculation unit 23 measures the position of the reference point according to the received GPS radio wave and obtains reference point position information. Similarly, observation point position information is generated for the GPS receivers 11b and 11c based on received GPS radio waves excluding prohibited radio waves.
[0030]
The observation point position information obtained in this way represents the position information of each GPS receiver in a three-dimensional manner over time, and this reference point position information and position information obtained from another GPS receiver. (Hereinafter referred to as other position information), the displacement of the slope can be obtained in a time-series and three-dimensional manner.
[0031]
The monitoring center 12 (that is, the computer system 12a) obtains slope displacement data (slope displacement data) as follows based on the reference point position information and other position information obtained as described above. . As described above, the reference point position information and other position information are given to the computer system 11a from the GPS receivers 11a to 11c, respectively. In the computer system 12a, slope displacement data is obtained at predetermined time intervals using the reference point position information and other position information.
[0032]
The slope displacement data is displayed with time on the horizontal axis and displacement on the vertical axis, and is displayed on the monitor 12b and stored in the database 12d for each slope. For example, as shown in FIGS. 4A to 4C, the slope displacement data is represented as a displacement point sequence in the north-south direction, the east-west direction, and the vertical direction (FIG. 4 (b) shows an east-west direction, and FIG. 4 (c) shows a vertical displacement point sequence).
[0033]
By the way, the slope displacement data described above includes variations (varies in a band shape) due to various external factors (for example, the state of GPS satellites, the influence of the ionosphere and troposphere, multipath, and baseline length). It is difficult to accurately grasp and evaluate the state of the slope from the slope displacement data. Therefore, the monitoring center 12 (that is, the computer system 12a) performs filtering processing and smoothing processing on the slope displacement data to generate processed displacement data (filter data).
[0034]
Here, the filtering process and the smoothing process will be described. Here, the system noise variance τ ^{2, the} observation noise variance σ ² , and the order k are obtained by estimating the state vector x _n using the Kalman filter algorithm. Then, _xn is obtained discretely, and the optimal _xn is estimated using the log likelihood and AIC.
[0035]
In other words, a state space _model, and _{x n = F n x n-} 1 + G n ν n, y n = H n x n + w n. Here, x _n : state vector that cannot be observed directly (stochastic system model), ν _n : system noise (mean 0, variance-covariance matrix Q _n ), y _n : observation data (observation model), w _n : observation noise ( The mean is 0 and the variance-covariance matrix R _n ), and F _n , G _n , and H _n are transition matrices defined by Gauss-Markov processes, respectively. And let this state space model be a probability difference equation. Assuming that H _{n xn} = t _n , y _n = t _n + w _n (observation model), Δkt _n = ν _n (when k = 1, Δt _n = t _n −t _n−1 = ν _n , Δkt _n Is the k-th order difference equation).
[0036]
Then, the Kalman filter is used to calculate the first-term prediction (first step), filter (second step), and smoothing (third step) as a series of flows, and the observed value y _n = {y ₁ , y _2, ..., a state under given are _{y n} x n = {x} 1, x 2, ..., seek _{x n}.}
[0037]
After performing the filtering process and the smoothing process in this way, the processed displacement data is stored in the database 12d together with the above-described displacement data and displayed on the monitor 12b. This processed displacement data is represented as a line segment indicated by a solid line in FIGS.
[0038]
As described above, the GPS coordinates are set by setting the mask coordinates with the position where the radio wave shield is present as the mask position, and the GPS radio waves coming from the direction of the mask position as the prohibited radio waves. It is possible to exclude GPS radio waves from GPS satellites that are seen and hidden with respect to low elevation angle GPS satellites and radio wave shields, and as a result, it is possible to accurately obtain the displacement of the relative position between the reference point and the observation point. It will be possible.
[0039]
Note that the mask coordinates are set in accordance with an imaging command input from the input device 12c. That is, in the GPS receiver that has received this imaging command, imaging is performed by the digital camera, and mask coordinates are obtained as described above. The mask coordinates are updated each time an image is taken with the digital camera.
[0040]
If the mask coordinates are updated in this way, the mask coordinates can be updated in accordance with the change in the surrounding environment where the GPS receiver is installed, and as a result, the displacement of the slope can be obtained with high accuracy. Become. At present, the number of GPS satellites that can be received at a certain point is 8-9. Therefore, as described above, even if the mask coordinates are defined, the number of GPS satellites (for example, 4 Enough).
[0041]
【The invention's effect】
As described above, in the present invention, on the coordinates indicating the azimuth with the sky direction at each of the GPS reference station and the GPS station as the elevation angle 90 °, the mask coordinates defining the position of the radio wave shielding object that blocks the GPS radio wave as the mask position are provided. Because the GPS radio wave that arrives from the mask position direction in the mask coordinates is set as a prohibited radio wave, the reference point position information and the position information are generated according to the other GPS radio waves excluding the prohibited radio wave. Even if a shield or the like is present, the state (displacement) of the slope can be accurately monitored.
[0042]
In the present invention, for each GPS reference station and each GPS station, an image is obtained by imaging the surroundings with the sky direction as an elevation angle of 90 °, and the mask coordinates in which the mask position is defined by recognizing the position of the radio wave shielding object from this image are obtained. Since they are generated, there is an effect that the mask coordinates can be updated as necessary.
[0043]
Since each of the GPS reference station and the GPS station performs imaging according to a command from the monitoring center, there is an effect that the mask coordinates can be easily updated according to the command from the monitoring center.
[0044]
In addition, since the GPS reference station and the GPS station are connected to the monitoring center via the network, there is an effect that a plurality of slopes can be monitored at the same time by the monitoring center.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a slope monitoring system according to the present invention.
FIG. 2 is a block diagram showing a configuration of a GPS receiver used in the slope monitoring system shown in FIG.
FIG. 3 is a diagram illustrating an example of mask coordinates set in a GPS receiver.
4 is a diagram showing observation data and processed displacement data obtained by the slope monitoring system shown in FIG. 1, wherein (a) shows a north-south direction, (b) shows a east-west direction, and (c). Is a diagram showing a vertical direction.
[Explanation of symbols]
11-1 to 11-N Slope monitoring devices 11a to 11c GPS receiver 11d Communication concentrator 11e Wireless concentrator 12 Monitoring center 12a Computer system 13 Wired communication line 16 Wireless repeater 23 Positioning calculation unit 24 Image processing unit 25 Mask coordinate setting Unit 26 Storage unit

Claims (3)

Used to monitor slope conditions,
A GPS reference station that is arranged at a position outside the slope, receives radio waves from GPS satellites, and outputs the radio waves as reference GPS data;
At least one GPS station disposed at a position within the slope, receiving radio waves from the GPS satellites and outputting the radio waves as GPS data;
A monitoring center that obtains the displacement of the slope based on the reference GPS data and the reference point position information indicating the position of the GPS reference station obtained from the GPS data and the position information indicating the position of the GPS station, respectively, and uses them as slope displacement data And
Each of the GPS reference station and the GPS station includes an imaging unit that captures an image of the surroundings with the sky direction as an elevation angle of 90 ° and obtains an image to which information indicating 16 directions is added ,
In the monitoring center, it is determined whether or not there is a radio wave shielding object that shields the GPS radio wave from the image obtained by the imaging means, and the position of the radio wave shielding object image in the image recognized as the radio wave shielding object as a mask position, provided with a mask coordinate generating means for generating a mask coordinates at a pitch of a predetermined elevation angle of the sky direction 16 the orientation coordinates to elevation 90 °,
The monitoring center uses the GPS reference station and the GPS radio wave arriving from the direction of the mask position in the mask coordinates for each GPS station as a prohibited radio wave, the reference point position information according to other GPS radio waves excluding the prohibited radio wave, and A slope monitoring system using the position information.   The slope monitoring system according to claim 1, wherein the GPS reference station and the GPS station are connected to the monitoring center by a network.   The slope monitoring system according to claim 2, wherein the imaging by the imaging unit is performed in accordance with a command from the monitoring center, and the mask coordinates are updated.

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