JP2004212070A - Slope monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make graspable precisely the state of a slope by reducing dispersion in slope displacement data and reducing missing data. <P>SOLUTION: A GPS transmitter which is a reference point is arranged on a position outside the slope, and one or more GPS transmitters are arranged on positions in the slope. A monitoring center acquires reference point position information for showing the position of the reference point GPS transmitter and position information for showing the positions of the GPS transmitters arranged on the slope, and acquires slope displacement data by determining the slope displacement based on the reference point position information and the position information. The monitoring center evaluates the slope displacement data corresponding to an evaluation index specified beforehand, and displays the slope displacement data, classified by color, corresponding to the evaluation result. In the monitoring center, preference of the slope displacement data is evaluated based on the evaluation index, and the slope displacement data determined not to be preferential are taken as missing slope displacement data, and the missing slope displacement data are interpolated based on the preferential slope displacement data determined to be preferential. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD 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 slope monitoring system capable of accurately measuring a slope displacement.
[0002]
[Prior art]
Generally, on slopes such as slopes, especially large-scale slopes with unstable elements, it is necessary to properly maintain the slopes because the danger of collapse always accompanies them. Protective works and countermeasures have been implemented. However, it is still unclear how factors such as weathering of the ground, transition of vegetation, and aging of protection works and countermeasures are related to slope collapse when maintaining slopes. For this reason, the state of the slope is constantly monitored to predict a slope collapse in advance.
[0003]
By the way, conventionally, a method of measuring displacement of a slope using GPS is known (hereinafter referred to as GPS slope measurement). In such a GPS slope measurement, for example, a reference placed at a distance on a slope is used. The slope displacement is measured by measuring the relative displacement between the point and the observation point. For example, a GPS receiver is arranged at each of a reference point and an observation point, and a reception signal (GPS signal) received by each GPS receiver is transmitted to a site office remote from a slope via a wireless line, An analysis device provided at the site office calculates the positional coordinates of the reference point and the observation point and the displacement of the relative position based on the GPS signal (see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 5-280978 (pages 2 to 3; FIG. 2)
[0005]
By the way, in the GPS slope measurement, GPS signals received by each GPS receiver are collected, analyzed by an analyzer or the like (so-called baseline analysis), and three-dimensional coordinate values (X, Y, Z coordinate values) are calculated. Obtained as slope displacement data, the slope displacement data is displayed on a monitor or the like with the horizontal axis as time. That is, the slope displacement data obtained as a result of the baseline analysis is displayed on a monitor or the like with the horizontal axis representing time and the vertical axis representing displacement (for example, represented as a sequence of displacement points in the north-south direction, the east-west direction, and the vertical direction). In the case of this baseline analysis, coordinate values smaller than a predetermined threshold value are discarded.
[0006]
Here, referring to FIG. 5, the processing in the conventional GPS slope measurement will be briefly described. First, when slope measurement by the GPS receiver is started (step S1), each GPS receiver (that is, the reference point and the observation point) is measured. The GPS signal (observation data) received from the point) is collected (step S2). Thereafter, a baseline analysis is performed on these observation data to obtain three-dimensional coordinate values (slope displacement data) on the slope (step S3). Then, each of the slope displacement data is evaluated, and it is checked whether or not the ratio, which is an evaluation index, exceeds a predetermined threshold (step S4). In step S4, for example, 1.5 or 2.0 in operation is used as the predetermined threshold.
[0007]
If the ratio exceeds a predetermined threshold, the slope displacement data is determined to be good (step S5) and displayed on the monitor (step S6). On the other hand, if the ratio is equal to or less than the predetermined threshold, it is determined to be defective, and the slope displacement data is discarded (no solution: step S7). In this way, if the slope displacement data is sequentially displayed on the monitor, the slope displacement data is graphically displayed with the horizontal axis representing time.
[0008]
[Problems to be solved by the invention]
By the way, as described above, when the slope displacement data is obtained by performing the baseline analysis of the GPS signal and the slope displacement data is displayed in a graph, each slope displacement data is evaluated, and the slope displacement data is evaluated in accordance with the evaluation result. As a result of determining whether to discard (that is, coordinate values), depending on the number of satellites used, missing data in the slope displacement data increases, and the situation of the slope displacement cannot be accurately displayed. Sometimes.
[0009]
On the other hand, in the conventional GPS slope measurement, only the ratio is used as an index for evaluating each slope displacement data, and even if the ratio of the slope displacement data exceeds a predetermined threshold value, as described above. When a graph is displayed on a monitor, variations may occur, and as a result, the situation of slope displacement may not be accurately displayed.
[0010]
An object of the present invention is to provide a slope monitoring system in which variation in slope displacement data is less likely to occur and a slope condition can be accurately grasped.
[0011]
Another object of the present invention is to provide a slope monitoring system capable of accurately grasping the state of a slope by substantially reducing missing data of the slope displacement data.
[0012]
[Means for Solving the Problems]
According to the present invention, a GPS reference station, which 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 receiving radio waves from the GPS satellites and outputting the radio waves as GPS data, and a reference indicating the reference GPS data and the position of the GPS reference station determined by the GPS data, respectively. A monitoring center for determining the displacement of the slope based on point position information and position information indicating the position of the GPS station to obtain slope displacement data as three-dimensional coordinate data, wherein the monitoring center is defined in advance. The slope displacement data is evaluated according to the evaluation index, and the slope displacement data is displayed in different colors according to the evaluation result. Slope monitoring system, characterized in that is obtained.
[0013]
In this way, in the monitoring center, the slope displacement data is evaluated according to a predetermined evaluation index, and the slope displacement data is displayed in different colors according to the evaluation result. It can be easily grasped, and the situation of the slope can be grasped accurately.
[0014]
Further, in the present invention, the monitoring center evaluates the superiority of the slope displacement data based on the predetermined evaluation index, and sets the slope displacement data determined to be not superior as missing slope displacement data, The monitoring center interpolates the missing slope displacement data based on the superior slope displacement data determined to be superior. In addition, the monitoring center may weight the missing slope displacement data in accordance with a deviation of the evaluation index from a threshold value to obtain the slope displacement data.
[0015]
As described above, the monitoring center evaluates the superiority of the slope displacement data based on the evaluation index defined in advance, and determines that the slope displacement data determined not to be superior is missing as the measured slope displacement data. If the missing slope displacement data is interpolated based on the superior slope displacement data obtained, the dispersion of the slope displacement data is reduced, and the missing measurement of the slope displacement data is substantially reduced. It can be grasped accurately. Even if the measured slope displacement data is weighted according to the deviation of the evaluation index from the threshold value to be used as the slope displacement data, the variation of the slope displacement data is reduced, and the lack of the slope displacement data is substantially reduced. The number of measurements is reduced, and the situation of the slope can be accurately grasped.
[0016]
As the evaluation index, for example, at least one of the ratio and the variance obtained when the reference GPS data and the GPS data are subjected to the baseline analysis are used.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. Note that, in the following description, the shape, dimensions, and the like are not limited to these unless otherwise specified.
[0018]
Referring to FIG. 1, first, the illustrated slope monitoring system includes a plurality of slope monitoring devices 11-1 to 11-N (N is an integer of 2 or more), and these slope monitoring devices 11 to 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, respectively, monitor and measure the state of the slopes, and send them 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 will be 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. The displacement (slope displacement) of each slope is monitored according to the first to Nth observation data obtained from the slope monitoring devices 11-1 to 11-N. The monitoring center 12 is located at a point distant from the slope monitoring devices 11-1 to 11-N, and collects these observation data remotely.
[0020]
The slope monitoring device (GPS measurement device) 11-n (n is any number from 1 to N) has at least two GPS (Global Positioning System) receivers (measurement devices), and is an example shown in the drawing. Has three GPS receivers 11a to 11c. One of them, for example, the GPS receiver 11a is arranged at a point other than the slope as a reference point receiver (GPS reference station). That is, the reference point receiver 11a is placed on a stable ground away from the slope.
[0021]
On the other hand, the other GPS receivers 11b and 11c are arranged on a slope (at least one GPS receiver may be arranged on the slope). The GPS receivers 11a to 11c receive radio waves (GPS radio waves) from at least four GPS satellites at a preset time interval (first time interval), and transmit GPS data at each of the above time intervals. Output as observation data. The time interval is set, for example, by an observation time setting command from the computer system 12a.
[0022]
These GPS receivers 11a to 11c are connected to a communication aggregator 11d or a wireless aggregator 11e used as a communication device, and the communication aggregator 11d is connected to a wired communication line 13. Then, the communication aggregator 11d sends each observation data to the monitoring center 12 via the wired communication line 13.
[0023]
Further, the wireless aggregator 11e sends each observation data to the wireless repeater 16 via a wireless line. Although one wireless repeater 16 is shown in FIG. 1, a plurality of wireless repeaters 16 are actually arranged, and a communication area is defined for each wireless repeater 16. The observation data is received from the radio aggregator 11e located in the communication area of. The wireless repeater 16 is connected to the above-described wired communication line 13, and observation data for each slope is transmitted from the wireless repeater 16 to the monitoring center 12. Note that information (GPS receiver identification information) for identifying the GPS receiver is added to each observation data.
[0024]
The observation data (GPS data) obtained as described above three-dimensionally represents the position information of each GPS receiver with time, and the position of the reference point receiver (GPS reference station) 11a is now described. Assuming that the information is reference point position information, displacement of the slope is chronologically and three-dimensionally determined based on the reference point position information and position information obtained from another GPS receiver (hereinafter referred to as other position information). Can be obtained.
[0025]
Referring to FIG. 2 as well, the monitoring center 12 (that is, the computer system 12a) performs a baseline analysis based on the reference point position information and other position information obtained as described above, and outputs the slope displacement data. (Slope displacement data: three-dimensional coordinate value) is obtained. That is, when the measurement of the slope displacement is started (Step P1), the observation data (GPS data) is collected from each GPS receiver in the computer system 12a (Step P2). In other words, each of the GPS receivers 11a to 11c provides reference point position information and other position information to the computer system 12a. The computer system 12a obtains the slope displacement data at predetermined time intervals using the reference point position information and other position information (step P3).
[0026]
Incidentally, the above-described slope displacement data varies depending on various external factors (for example, the state of the GPS satellite, the influence of the ionosphere and the troposphere, the multipath, and the base line length). For this reason, at the time of the baseline analysis, the computer system 12a generates various evaluation indices (hereinafter referred to as detection evaluation indices: Step P4). For example, the evaluation indices include the number of used GPS satellites (baseline analysis). ), The number of observed GPS satellites (the number of GPS satellites that could be received by the GPS receiver), the quality of received data, various DOPs, ratios, and variances.
[0027]
Which evaluation index is to be used is set together with the threshold value from an input device 12c connected to the computer system 12a, and the computer system 12a sets the slope according to the set evaluation index threshold value (hereinafter referred to as evaluation threshold value). The displacement data is classified by color, and the slope displacement data is temporarily displayed on the monitor (output device) 12b by color (Step P5). In other words, after the detection evaluation index related to the slope displacement data is classified by the evaluation threshold, the slope displacement data is color-coded for each predetermined range from the reference value using the evaluation threshold as a reference value.
[0028]
For example, if the variance is used as an evaluation index, the slope displacement data is color-coded every time the variance deviates from the reference value of the variance by α%. The slope displacement data corresponding to the detection evaluation index is displayed in red, and the slope displacement data corresponding to the detection evaluation index in the range from the evaluation threshold to (evaluation threshold + α%) is displayed in blue. Then, the slope displacement data corresponding to the detection evaluation index in the range from the evaluation threshold to (evaluation threshold + 2α%) is displayed in green (note that when other evaluation indices are used, color classification is performed in the same manner. Is done).
[0029]
Then, the computer system 12a evaluates the slope displacement data according to the evaluation index thresholds (evaluates the likelihood of the slope displacement data: step P6). That is, the computer system 12a evaluates the above-described detection evaluation index corresponding to the slope displacement data according to the evaluation threshold value, and evaluates the superiority of the slope displacement data (that is, evaluates whether or not the solution is superior). Do).
[0030]
As a result, the slope displacement data (coordinate values: hereinafter referred to as non-dominant slope data) evaluated as not being a superior solution is temporarily discarded (step P7), and a storage unit (memory: shown in the drawing) incorporated in the computer system 12a. ). On the other hand, according to the slope displacement data evaluated as a superior solution (hereinafter referred to as superior slope displacement data: step P8), a trend process described later is performed.
[0031]
FIG. 3 is a diagram showing the transition of the slope displacement data, showing an example in which variance is used as the above-mentioned evaluation index and the threshold value is set to 3.9 or more. It can be seen that the variation caused by the path can be removed. That is, before the slope displacement data is evaluated using the variance, the variation is extremely large (see FIG. 3A). However, when the variance is used as the evaluation index, the variation can be extremely reduced, and multipath causes the variation. It can be seen that certain non-dominant slope displacement data can be deleted (see FIG. 3B).
[0032]
Further, the computer system 12a uses the superior slope displacement data to interpolate the missing slope displacement data (step P9). That is, the computer system 12a predicts the missing slope displacement data based on the superior slope displacement data, predicts the slope displacement data to be positioned between the superior slope displacement data, and generates the predicted slope displacement data. (Step P10). Then, the computer system 12a executes a trend process according to the superior slope displacement data and the predicted slope displacement data (step P11). The superior slope displacement data and the predicted slope displacement data are displayed on the monitor 12b.
[0033]
Here, the interpolation process will be described. In the interpolation process, the variance τ ² of the system noise, the variance σ ^{2 of the} observation noise, and the order k are estimated by, for example, a method of estimating the state vector x _n by an algorithm of a Kalman filter. Then, x _n is obtained discretely, and the optimal x _n is estimated using log likelihood and AIC.
[0034]
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 : a state vector that cannot be directly observed (stochastic system model), ν _n : system noise (mean 0, variance-covariance matrix Q _n ), y _n : observation data (observation model), w _n : observation noise ( Mean 0, variance-covariance matrix R _n ), and F _n , G _n , and H _n are transition matrices defined by Gauss-Markov processes. Then, this state space model is defined as a probability difference equation. When _{H n x n = t n,} y n = t n + w n ( observation model), for _{Δkt n = ν n (k =} 1, Δt n = t n -t n -1 = ν n, Δkt n Is a k-th order difference equation). Then, the Kalman filter performs one-period prediction (first step), obtains predicted slope displacement data according to the superior slope displacement data, and interpolates the slope displacement data. In this way, if the predicted slope displacement data is predicted from the superior slope displacement data using the Kalman filter algorithm and interpolation is performed, the missing slope displacement data can be interpolated with extremely high accuracy.
[0035]
Next, a description will be given of the trend process. In the trend process, a filtering process and a smoothing process are performed on the superior slope displacement data and the predicted slope displacement data to generate processed displacement data (filter data). In the filtering process and the smoothing process, for example, a method of estimating the state vector _xn by an algorithm of a Kalman filter, the above-mentioned one-term ahead prediction (first step), the filter (second step), and the smoothing ( and calculating a third step) as the sequential flow, observed value _{y n = {y 1, y} 2, ..., the state of the _{underlying y n)} is given _{x n = {x 1, x} 2, ..., x _n }.
[0036]
After the filtering process and the smoothing process are performed in this way, the processed displacement data is stored in the database 12d and displayed on the monitor 12b as a graph (step P12). FIG. 4 shows processed displacement data (filter data) in the north-south direction together with slope displacement data. In FIG. 4, the solid line is the processed displacement data, and the dotted line is the slope displacement data. As shown in FIG. 4, when the slope displacement data is filtered and smoothed and displayed as a graph, the processed displacement data is displayed as a solid line in a graph, so that the tendency of the slope displacement can be easily grasped. Become.
[0037]
After obtaining the processed displacement data in this way, if the processed displacement data exceeds, for example, a preset displacement threshold value (step P13), the computer system 12a issues an alarm. (Step P14).
[0038]
By the way, instead of performing the above-described interpolation processing, the non-dominant slope displacement data stored in the database 12d and the above-described superior slope displacement data are processed according to the weight setting processing, and then the above-described trend processing is performed. Is also good. For example, when one of the interpolation processing and the weight setting processing is selected by the input device 12c, and the weight setting processing is selected, the computer system 12a performs the weight setting processing as shown by a broken line in FIG. (Step P15).
[0039]
That is, as described above, the non-dominated slope displacement data and the dominant slope displacement data are classified according to the deviation from the reference value. Therefore, in the weight setting process, a weight coefficient is set for each of the sections. Alternatively, the non-dominant slope displacement data may be corrected according to the weight coefficient, and the corrected slope displacement data (including the dominant slope displacement data) may be subjected to trend processing. The corrected slope displacement data (including superior slope displacement data) is displayed on the monitor 12b.
[0040]
【The invention's effect】
As described above, in the present invention, the monitoring center evaluates the slope displacement data in accordance with a predetermined evaluation index, and displays the slope displacement data in different colors according to the evaluation result. Variations in the slope displacement data can be easily grasped, and as a result, the situation of the slope can be grasped accurately.
[0041]
In the present invention, the monitoring center evaluates the superiority of the slope displacement data based on the evaluation index defined in advance, and determines that the slope displacement data determined to be not superior is missing as the measured slope displacement data, and is determined to be superior. Since the missing slope displacement data is interpolated based on the superior slope displacement data, the dispersion of the slope displacement data is reduced, and the lack of missing slope displacement data is substantially reduced. There is an effect that it can be grasped.
[0042]
According to the present invention, the monitoring center evaluates the superiority of the slope displacement data based on a predetermined evaluation index, and evaluates the missing slope displacement data by using the slope displacement data determined to be not superior as missing slope displacement data. Since the slope displacement data is weighted according to the deviation of the index from the threshold value, the dispersion of the slope displacement data is reduced, and the missing data of the slope displacement data is substantially reduced, and the condition of the slope is reduced. There is an effect that can be accurately grasped.
[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 flowchart for explaining processing in the slope monitoring system shown in FIG. 1;
3A and 3B are diagrams illustrating an example of slope displacement data, in which FIG. 3A is a graph showing slope displacement data before evaluation using an evaluation index, and FIG. 3B is a diagram using variance, which is one of the evaluation indexes. It is a graph which shows the slope displacement data after performing evaluation.
FIG. 4 is a graph showing an example of processed displacement after trend processing of slope displacement data.
FIG. 5 is a flowchart showing an example of a process used in conventional slope displacement measurement.
[Explanation of symbols]
11-1 to 11-N Slope Monitoring Devices 11a to 11c GPS Receiver 11d Communication Aggregator 11e Wireless Aggregator 12 Monitoring Center 12a Computer System 13 Wired Communication Line 16 Wireless Repeater

Claims (4)

Used to monitor the condition of slopes,
A GPS reference station arranged at a position outside the slope, receiving a radio wave from a GPS satellite and outputting the radio wave as reference GPS data;
At least one GPS station arranged at a position in the slope, receiving radio waves from the GPS satellites and outputting the radio waves as GPS data;
Based on the reference GPS data and the GPS data, the displacement of the slope is determined based on the reference point position information indicating the position of the GPS reference station and the position information indicating the position of the GPS station, respectively. A monitoring center for certain slope displacement data,
The monitoring center evaluates the slope displacement data according to a predetermined evaluation index, and displays the slope displacement data in different colors in accordance with the evaluation result. . The monitoring center evaluates the superiority of the slope displacement data based on the predetermined evaluation index, and sets the slope displacement data determined to be not superior as missing slope displacement data,
2. The slope monitoring system according to claim 1, wherein the monitoring center is configured to interpolate the missing slope displacement data based on superior slope displacement data determined to be superior. 3. In the monitoring center, the superiority of the slope displacement data is evaluated based on the predefined evaluation index, and the slope displacement data determined to be not superior is regarded as missing slope displacement data.
2. The slope monitoring device according to claim 1, wherein the monitoring center weights the missing slope displacement data in accordance with a deviation of the evaluation index from a threshold, and sets the weighted slope displacement data as the slope displacement data. 3. system. The slope monitoring system according to claim 1, wherein at least one of a ratio and a variance obtained when the reference GPS data and the GPS data are subjected to baseline analysis is used as the evaluation index.

Images