Bridge displacement monitoring system

Abstract

To solve conventional problems, that is, to provide a bridge displacement monitoring system capable of continuously measuring a displacement of a bridge member and determining whether or not the displacement amount is appropriate after subtracting a displacement due to a temperature.SOLUTION: A bridge displacement monitoring system according to the present invention is a system for monitoring the displacement of a bridge, and includes temperature measurement means, positioning means, observation point displacement calculation means, smooth displacement calculation means, temperature-based displacement generation means, correlation value calculation means, processing method selection means, temperature displacement calculation means, displacement difference calculation means, and first warning output means. The smooth displacement calculation means performs two or more types of noise processing on the observation point displacement to obtain two or more types of "smooth displacements", and the temperature-based displacement generation means generates two or more types of "temperature-based displacement data sets" based on the "time-based temperature data set" and the two or more types of "time-based displacement data sets".SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to technology related to bridge displacement monitoring, and more specifically, to a bridge displacement monitoring system that can detect abnormal displacement by comparing displacement obtained by satellite positioning with temperature displacement obtained by structural analysis. [Background technology]

[0002] It has been pointed out that the construction infrastructure (hereafter referred to as "construction infrastructure"), which was developed intensively during the period of high economic growth, is already showing signs of considerable deterioration. In 2014, the Council for Social Capital Development compiled a "Proposal for Full-Scale Implementation of Measures to Counter Aging Roads," which cited the example of the Sasago Tunnel in 2012 and sounded the alarm that "in the near future, this will lead to fatal incidents involving human lives and social infrastructure, such as the collapse of bridges," and strongly advocated the importance of maintaining and managing construction infrastructure.

[0003] With this as a background, the national government has issued a ministerial ordinance amending part of the Road Act Enforcement Regulations, formulating regular inspection guidelines that indicate specific inspection methods for construction infrastructure, areas to look for in major abnormalities, and photographs of judgment examples, etc. For example, with regard to bridges, the target is bridges with a length of 2.0 m or more, which is said to amount to approximately 700,000, and the initial inspection is to be carried out within two years of opening to service, with regular inspections thereafter to be carried out once every five years.

[0004] Bridge inspections involve detecting cracks in concrete and other damaged areas, and recording the results for later review. For example, when detecting cracks in a bridge's concrete deck, not only must detailed information such as the extent of the crack (length, width, etc.) be recorded, but also where the cracks are located. In conventional inspections, cracks are detected visually, and the location of the cracks is sometimes recorded on-site on a previously prepared drawing of the structure.

[0005] Conducting bridge inspections like this requires a lot of time and manpower, and therefore is quite costly. In particular, to determine whether a crack is harmful or not, and whether there is even a crack at all, the inspector must have a great deal of experience and knowledge. Furthermore, given the recent labor shortage in the construction industry, it is becoming more difficult to secure suitable inspectors for bridge inspections.

[0006] Crack inspection is certainly one way to check the soundness of a bridge or to detect abnormalities, but it is limited to concrete members, meaning it is difficult to apply to steel bridges. Also, although it is extremely useful to detect harmful cracks, it is a method of checking abnormalities after the fact, so to speak, and does not predict areas where abnormalities may occur in the future.

[0007] Therefore, surveys are being conducted on bridges in service to grasp their soundness by measuring the amount of displacement. It is possible to predict that members that frequently show abnormal displacement may be deformed in the future, and therefore measures such as reinforcement can be taken at an early stage. For example, Patent Document 1 proposes a technology in which acceleration sensors are installed at various points on a bridge and the amount of displacement when a vehicle passes is calculated based on the data acquired by these acceleration sensors. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2021-095684 A Summary of the Invention [Problem to be solved by the invention]

[0009] The technology disclosed in Patent Document 1 grasps the displacement caused by what is called a live load associated with vehicle travel. However, what should be paid more attention to for bridge components is the displacement caused by dead loads such as the bridge's own weight. In other words, while the displacement caused by live loads is temporary, the displacement caused by dead loads is cumulative, and if the amount of displacement continues to increase, there is a risk that damage may eventually occur. For this reason, the technology in Patent Document 1 cannot be said to be sufficient in terms of predicting damage to components.

[0010] It is known that bridge components deform in response to temperature. Therefore, it is important to determine whether the deformation is harmful due to dead load or simply due to temperature rise. Even if bridge components deform when temperatures rise in summer, etc., the deformation will return to normal when temperatures return to normal, so there is no need to pay special attention to it. On the other hand, if the amount of deformation exceeds the amount of deformation due to temperature rise and is at a level that cannot be ignored, it is necessary to continue to pay attention and take measures as necessary.

[0011] The object of the present invention is to solve the problems of the conventional technology, namely, to provide a bridge displacement monitoring system that can continuously measure the displacement of bridge components and determine whether the amount of displacement is appropriate after deducting the displacement caused by temperature. [Means for solving the problem]

[0012] The present invention focuses on the fact that multiple types of noise processing are performed on the displacement obtained by satellite positioning, and by comparing it with the change in displacement due to temperature change, the most appropriate noise processing is selected and then the amount of displacement excluding the displacement due to temperature is calculated, and is an invention based on an idea that has not been seen in the past.

[0013] The bridge displacement monitoring system of the present invention is a system for monitoring bridge displacement, and includes a positioning means, a temperature measuring means, an observation point displacement calculation means, a smoothed displacement calculation means, a temperature-specific displacement generation means, a correlation value calculation means, a processing method selection means, a temperature displacement calculation means, a displacement difference calculation means, and a first warning output means. Among these, the positioning means is a means for repeatedly measuring the position of an observation point arranged on a target member to obtain an "observation point coordinate", the temperature measuring means is a means for acquiring a "member temperature" by repeatedly measuring the temperature of the target member, and the observation point displacement calculation means is a means for obtaining an "observation point displacement" of an observation point based on the observation point coordinate. The smoothed displacement calculation means is a means for obtaining two or more types of "smoothed displacement" by performing two or more different types of noise processing on a plurality of observation point displacements, and the temperature-specific displacement generation means is a means for generating two or more types of "temperature-specific displacement data sets" based on a "time-specific temperature data set" and two or more types of "time-specific displacement data sets". The correlation value calculation means is a means for calculating a "correlation value" indicating the degree of correlation between the time-specific displacement data set and the temperature-specific displacement data set generated based on the time-specific displacement data set. The processing method selection means is a means for selecting a "maximum correlation value" indicating the largest value among the correlation values ​​calculated by the correlation value calculation means, and for selecting a noise processing related to the maximum correlation value from among two or more types of noise processing as a "determined noise processing". The temperature displacement calculation means is a means for calculating a "temperature displacement" of a target member by performing a structural analysis with temperature as a condition, the displacement difference calculation means is a means for calculating a "displacement difference" between an observation point displacement and a temperature displacement, and the first warning output means is a means for outputting a warning when the displacement difference exceeds the displacement difference threshold by checking the displacement difference against a displacement difference threshold. The time-specific temperature data set includes a plurality of time-specific temperature data, the time-specific displacement data set includes a plurality of time-specific displacement data, and the temperature-specific displacement data set includes a plurality of temperature-specific displacement data. The time-specific temperature data is a combination of a "temperature measurement time" measured by the temperature measurement means and a "member temperature" related to the temperature measurement time, the time-specific displacement data is a combination of a "positioning time" measured by the positioning means and an observation point displacement related to the positioning time, and the temperature-specific displacement data is a combination of a member temperature and an observation point displacement.The observation point displacement to be combined with the component temperature when the temperature-specific displacement data set is generated is the observation point displacement related to the same (or approximate) positioning time as the temperature measurement time related to the component temperature. The displacement difference calculation means calculates the displacement difference between the observation point displacement and the temperature displacement between the same component temperatures based on the temperature-specific displacement data set related to the determination noise processing.

[0014] The bridge displacement monitoring system of the present invention may also be one in which the observation point displacement calculation means determines the “static displacement.” In this case, the observation point displacement calculation means performs baseline analysis on the positioning data to determine the “static coordinates” of the observation point based on the static positioning, and determines the “static displacement” of the observation point based on the static coordinates.

[0015] The bridge displacement monitoring system of the present invention may further include a threshold calculation means for calculating a displacement difference threshold. In this case, the threshold calculation means calculates the displacement difference threshold by performing statistical processing on the multiple displacement differences calculated by the displacement difference calculation means. Then, the first warning output means compares the displacement difference with the displacement difference threshold calculated by the threshold calculation means.

[0016] The bridge displacement monitoring system of the present invention may further include a regression equation generating means for generating a regression equation based on the time-based displacement data set and the temperature-based displacement data set generated based on the time-based displacement data set.

[0017] The bridge displacement monitoring system of the present invention may further include an RTK displacement calculation means, an RTK moving average calculation means, an RTK difference calculation means, and a second warning output means. The RTK displacement calculation means is a means for performing a baseline analysis on the positioning data to obtain the "RTK coordinates" of the observation point based on the real-time kinematic positioning, and for obtaining the "RTK displacement" related to the observation point based on the RTK coordinates. The RTK moving average calculation means is a means for calculating the "RTK moving average value" which is the average value of multiple RTK displacements included in the "average target section" going back a certain period from the "interest time". The RTK difference calculation means is a means for calculating the "RTK difference" which is the difference between the RTK moving average value and the temperature displacement. However, this temperature displacement is the temperature displacement calculated by the temperature displacement calculation means based on the member temperature related to the temperature measurement time that is the same as (or close to) the interest time related to the RTK moving average value. The second warning output means is a means for comparing the RTK difference with the RTK difference threshold, and outputting a warning when the RTK difference exceeds the RTK difference threshold.

[0018] The bridge displacement monitoring system of the present invention may also include an RTK displacement calculation means, an RTK difference calculation means, and a second warning output means. In this case, the RTK difference calculation means calculates the difference between the RTK displacement and the temperature displacement at the time of interest as the "RTK difference."

[0019] The bridge displacement monitoring system of the present invention may further include an RTK threshold calculation means for calculating an RTK difference threshold. In this case, the RTK threshold calculation means calculates the RTK difference threshold by performing statistical processing on a plurality of RTK differences included in a section (e.g., an average target section) going back a predetermined period from the time of interest. Then, the second warning output means compares the RTK difference with the RTK difference threshold. However, this RTK difference threshold is an RTK difference threshold based on a time of interest earlier than the time of interest related to the RTK difference. Effect of the Invention

[0020] The bridge displacement monitoring system of the present invention has the following effects. (1) The bridge displacement can be appropriately monitored because the judgment is made after deducting the displacement due to temperature, i.e., after detecting the true displacement due to dead load. (2) The system can automatically and continuously monitor bridge displacement, making it possible to predict which components may be subject to deformation in the future, and therefore to take measures such as reinforcement at an early stage. (3) Because monitoring can be done without relying on inspectors, it can be done without difficulty even in the recent environment of labor shortages. In addition, there is no need to secure inspectors with considerable experience and knowledge, which means that misjudgments due to so-called human error can be avoided. [Brief description of the drawings]

[0021] [Figure 1] A side view of a road bridge in which positioning devices and temperature measuring devices are installed in the girder part at the center of the span, the piers, and the abutments. [Diagram 2] FIG. 2 is a block diagram showing the main configuration of the bridge displacement monitoring system of the present invention for outputting a first warning. [Diagram 3] FIG. 4 is a block diagram showing the main configuration of the bridge displacement monitoring system of the present invention for outputting a second warning. [Figure 4] (a) is a graph showing the trend in north-south displacement at "observation point No. 1", (b) is a graph showing the trend in east-west displacement at "observation point No. 1", and (c) is a graph showing the trend in vertical displacement at "observation point No. 1". [Diagram 5] FIG. 11 is a formula diagram for explaining processing by a smoothed displacement calculation means. [Figure 6] FIG. 4 is a model diagram for explaining a Kalman filter and smoothing processing by a smoothed displacement calculation means. [Figure 7] (a) is a model diagram that shows a schematic diagram of a time-based displacement data set consisting of multiple time-based displacement data, (b) is a model diagram that shows a schematic diagram of a time-based temperature data set consisting of multiple time-based temperature data, and (c) is a model diagram that shows a schematic diagram of a temperature-based displacement data set consisting of multiple temperature-based displacement data. [Figure 8](a) is a graph showing a "positioning time-smooth displacement trend graph" in which multiple time-specific displacement data are plotted on a coordinate system consisting of two axes, "time" and "displacement." (b) is a graph showing a "temperature measurement time-component temperature trend graph" in which multiple time-specific temperature data are plotted on a coordinate system consisting of two axes, "time" and "temperature." (c) is a graph showing a "component temperature-smooth displacement trend graph" in which multiple temperature-specific displacement data are plotted on a coordinate system consisting of two axes, "temperature" and "displacement." [Figure 9] FIG. 4 is a model diagram showing a procedure in which a temperature-specific displacement generating means generates a temperature-specific displacement data set. [Figure 10] FIG. 1 is a model diagram showing a correlation value and a regression equation generated based on a time-based displacement data set and a temperature-based displacement data set generated based on the time-based displacement data set. [Figure 11] FIG. 11 is a model diagram illustrating a procedure in which a threshold calculation means calculates a “displacement difference threshold”. [Figure 12] FIG. 13 is a model diagram explaining the procedure by which the RTK moving average calculation means calculates the “RTK moving average value.” [Figure 13] FIG. 2 is a flow chart showing an example of the main process flow until the bridge displacement monitoring system of the present invention determines a "displacement difference." [Figure 14] FIG. 2 is a flow chart showing an example of the main processing flow until the bridge displacement monitoring system of the present invention determines the "RTK difference." DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An example of an embodiment of the bridge displacement monitoring system of the present invention will be described with reference to the drawings. The bridge displacement monitoring system of the present invention monitors the displacement of a target member (hereinafter referred to as "target member") of a bridge, and obtains the displacement of the target member (hereinafter referred to as "observation point displacement") by positioning using a positioning satellite ST, and obtains the displacement of the target member (hereinafter referred to as "temperature displacement") by structural analysis based on the temperature of the target member (hereinafter referred to as "member temperature"). For this reason, as shown in FIG. 1, a receiver RC that receives radio waves (carrier waves) from the positioning satellite ST is installed on the target member, and a "temperature measuring means 102" that can continuously obtain the member temperature is also installed. For example, in FIG. 1, a receiver RC and a temperature measuring means 102 are installed on the girder part at the center of the span, the pier, and the abutment.

[0023] Figures 2 and 3 are block diagrams showing the main configuration of the bridge displacement monitoring system 100 of the present invention, of which Figure 2 is a block diagram for outputting a warning by a first warning output means (hereinafter referred to as the "first warning"), and Figure 3 is a block diagram for outputting a warning by a second warning output means (hereinafter referred to as the "second warning"). As shown in these figures, the bridge displacement monitoring system 100 of the present invention is mainly composed of a positioning means 101, a temperature measurement means 102, an observation point displacement calculation means 103, a smoothed displacement calculation means 104, a temperature-specific displacement generation means 105, a correlation value calculation means 106, a processing method selection means 107, a temperature displacement calculation means 108, a displacement difference calculation means 109, and a first warning output means 110, and can also be composed of a threshold calculation means 111, a regression equation generation means 112, a time-specific displacement generation means 113, a time-specific temperature generation means 114, an RTK displacement calculation means 115, an RTK moving average calculation means 116, an RTK difference calculation means 117, a second warning output means 118, an RTK threshold calculation means 119, a positioning data storage means 120, a component temperature storage means 121, a 3D model storage means 122, etc.

[0024] The observation point displacement calculation means 103, smoothed displacement calculation means 104, temperature-specific displacement generation means 105, correlation value calculation means 106, processing method selection means 107, temperature displacement calculation means 108, displacement difference calculation means 109, first warning output means 110, threshold calculation means 111, regression equation generation means 112, time-specific displacement generation means 113, time-specific temperature generation means 114, RTK displacement calculation means 115, RTK moving average calculation means 116, RTK difference calculation means 117, second warning output means 118, and RTK threshold calculation means 119 constituting the bridge displacement monitoring system 100 can be manufactured as dedicated means or can use a general-purpose computer device. In other words, the processing of these various means is performed by having the computer device execute arithmetic processing by a predetermined program. This computer device is equipped with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), memory such as ROM and RAM, and some also include input means such as a mouse and keyboard and a display, and can be configured, for example, as a personal computer (PC) or a server.

[0025] The positioning data storage means 120, the member temperature storage means 121, and the 3D model storage means 122 can be implemented in a storage device of a general-purpose computer (for example, a personal computer) or in a database server. When implemented in a database server, the database server can be placed in a local network (LAN: Local Area Network) or can be a cloud server that stores data via the Internet.

[0026] Below, each of the main elements constituting the bridge displacement monitoring system 100 of the present invention will be described in detail.

[0027] (Temperature measurement means) The temperature measuring means 102 is installed on one or more target components as planned, as shown in Fig. 1, and measures the "component temperature" of the target component. As the temperature measuring means 102, various thermometers that have been used in the past can be used, and a thermometer that directly measures the component temperature of the target component can be used, or a thermometer that measures the ambient air temperature of the target component as the component temperature can be used. However, the temperature measuring means 102 is assumed to repeatedly acquire the component temperature periodically (or intermittently). For convenience, the time at which the temperature measuring means 102 measures the component is referred to as the "temperature measurement time". The component temperature measured by the temperature measuring means 102 and the temperature measurement time are transmitted, for example, by a communication means and then stored in the component temperature storage means 121 (Fig. 2).

[0028] (Positioning means) The positioning means 101 includes a receiver RC, a communication means, and an analysis means, and may also include a power generation means. The receiver RC is installed in one or more planned target components as shown in FIG. 1 and is used for the Global Navigation Satellite System (GNSS), that is, it is a device that receives radio waves (carrier waves) from a positioning satellite ST. The receiver RC can receive signals from four or more satellites at the same time, and is preferably capable of static positioning and kinematic positioning (particularly real-time kinematic positioning). The receiver RC is installed not only in the planned target components, but also at reference points (fixed points) other than the target components.

[0029] The "power generation means" constituting the positioning means 101 generates electricity to be supplied to the receiver RC and the communication means, and can be, for example, a solar power generation device. By installing this power generation means, it is possible to avoid using commercial electricity, and furthermore, it is possible to omit power distribution lines on the bridge, which is preferable in terms of scenery and maintenance. The receiver RC can also be equipped with a calculation means. This calculation means determines the coordinates of the observation point, i.e., it calculates the coordinates on site (bridge).

[0030] The "analysis means" constituting the positioning means 101 is a means for determining the three-dimensional coordinates (hereinafter referred to as "observation point coordinates") of the observation point (i.e., the target component) based on data repeatedly received by the receiver RC (hereinafter simply referred to as "received data"). For convenience, the time at which the receiver RC receives the received data will be referred to simply as the "positioning time". The analysis means can calculate the observation point coordinates using various conventional analysis techniques. For example, the analysis means can be designed to calculate the observation point coordinates using a "point positioning method" such as absolute point positioning or differential positioning, or it can be designed to calculate the observation point coordinates using an "interferometric positioning method" such as static positioning or kinematic positioning.

[0031] Among the interferometric positioning methods, static positioning is a method of determining the coordinates of an observation point by observing four or more satellites with multiple receivers and performing baseline analysis on the data received by the receiver RC. This static positioning method can determine the coordinates of an observation point with the highest accuracy (horizontal accuracy of about 5 to 10 mm), but one analysis requires a relatively long observation time (for example, one hour). On the other hand, kinematic positioning is a method of determining the coordinates of an observation point by performing baseline analysis on the data received by the receiver RC, and although it allows observation in a short time (for example, 120 to 3,600 points / hour), its accuracy is inferior to that of static positioning (horizontal accuracy of about 20 to 30 mm). For convenience, here, the observation point coordinates determined by the analysis means using the static positioning method will be referred to as "static coordinates", and the observation point coordinates determined by the kinematic positioning method will be referred to as "RTK coordinates". The data received by the receiver RC of the positioning means 101, the positioning time, and the observation point coordinates calculated by the analysis means are stored in the positioning data storage means 120 (FIG. 2).

[0032] (Method of calculating observation point displacement) The observation point displacement calculation means 103 is a means for calculating the "observation point displacement" of the observation point (i.e., the target component) based on the observation point coordinates calculated by the positioning means 101. Specifically, the observation point displacement calculation means 103 reads out the observation point coordinates (e.g., static coordinates) stored in the positioning data storage means 120, and calculates the difference between the "initial (at the time of installation) observation point coordinates" of the observation point and the "observation point coordinates based on the current positioning" as the observation point displacement. Note that since the observation point coordinates are three-dimensional coordinates, the observation point displacement calculated from the observation point coordinates at two times (initial and current) can also be obtained as a displacement vector having a magnitude (amount of displacement) and a direction (direction of displacement).

[0033] (Smoothed displacement calculation means) It is known that data obtained by GNSS positioning varies in value as shown in Fig. 4 due to various error factors such as satellite positioning, sky visibility, and weather conditions. For example, even in the horizontal direction (north-south direction NS, east-west direction EW), which is considered to have relatively high accuracy, there is variation of about ±5 mm + 1 ppm × D (D: baseline length km), and in the vertical direction (UD), there is variation of about ±10 mm + 1 ppm × D. In other words, the positioning means 101 determines the observation point coordinates in a state containing noise, and the observation point displacement calculation means 103 determines the observation point displacement in a state containing noise.

[0034] Therefore, in the present invention, the smoothed displacement calculation means 104 performs "noise processing" to remove noise from the observation point displacement. For convenience, the observation point displacement from which noise has been removed by the smoothed displacement calculation means 104 is specifically referred to as "smoothed displacement." However, the smoothed displacement calculation means 104 performs two or more types of noise processing on the observation point displacement, that is, it obtains two or more types of smoothed displacement.

[0035] When the smoothed displacement calculation means 104 calculates the smoothed displacement, various conventionally used noise processing methods can be adopted, and for example, a specification can be made to perform statistical processing using a "trend model" and a "state space model" (hereinafter, for convenience, referred to as "trend model processing"). The contents of the trend model processing will be described in detail below with reference to Fig. 5 and Fig. 6. Fig. 5 is a formula diagram for explaining the processing by the smoothed displacement calculation means 104, and Fig. 6 is a model diagram for explaining the Kalman filter and smoothing processing.

[0036] "Time-series measurement data" such as positioning data can be considered as a "displacement trend" plus a "variation component." If the variation component is treated as simple normal white noise, it can be expressed by the observation model based on Equation 1 in Figure 5. In addition, by using Equations 2 and 3 in Figure 5, the time series Y n Trend U n It is possible to set up a model for estimating the trend component model, that is, a “trend model” that combines the observation model of Equation 1 with the trend component model.

[0037] In time series analysis, in many cases, it can be formulated as a state estimation problem for a state space model. For example, by using equations 4 and 5 in Figure 5, a trend model can be expressed as a "state space model." Then, for this state space model, state estimation using a Kalman filter and smoothing processing can be performed to remove noise. In a state space model state estimation problem, the time series Y n Based on the positioning data of state x nIt is important to estimate the displacement of the bridge. However, regression analysis, which is usually performed in time series analysis, tracks abnormal values ​​(observation values ​​with extremely large errors) contained in the positioning data too closely, and it may not be possible to distinguish between the abnormal values ​​and bridge displacement. Therefore, as shown in Figure 6, it is advisable to apply the Kalman filter algorithm to estimate the state. In the method shown in Figure 6, a one-period-ahead prediction is made from the current GNSS measurement values ​​(positioning data), and when new observation point displacements (observation point coordinates) are obtained, the prediction error is evaluated, thereby improving the estimation accuracy. While this process is performed at all times, filtering and smoothing processing using the fixed interval smoothing method are performed every time new observation point displacements (observation point coordinates) are obtained.

[0038] Then, two or more types of noise processing can be performed to obtain two or more types of smoothed displacements, such as a trend model processing using a first-order difference for all observation point displacements from the first positioning to the current positioning (hereinafter referred to as "accumulated data") as the "first noise processing", a trend model processing using a second-order difference for the accumulated data as the "second noise processing", and a trend model processing using a first-order difference for observation point displacements included in a section going back a predetermined period from the current positioning (hereinafter referred to as "section-limited data") as the "third noise processing". Of course, a trend model processing using a second-order difference for the section-limited data can be performed to obtain a smoothed displacement, and a trend model processing using a third-order or higher difference for the accumulated data or section-limited data can be performed to obtain a smoothed displacement. Furthermore, a noise processing using a conventional method different from the trend model processing can be performed to obtain a smoothed displacement. The two or more types of smoothed displacements obtained here can be stored in the positioning data storage means 120.

[0039] (Temperature displacement calculation means) The temperature displacement calculation means 108 is a means for calculating the temperature displacement of the target components by performing a structural analysis for each of the one or more planned target components, with the component temperatures of the target object as a condition. The structural analysis performed here is performed using a "three-dimensional framework model" that is a three-dimensional model of the target bridge. Specifically, the temperature displacement calculation means 108 reads out the temperature displacement from the component temperature storage means 121 and the three-dimensional framework model from the 3D model storage means 122, and then calculates the temperature displacement of the target components by various conventional analysis methods.

[0040] (Time-dependent displacement generation means) The time-based displacement generating means 113 is a means for generating a "time-based displacement data set." Here, the time-based displacement data set includes a plurality of "time-based displacement data" as shown in FIG. 7(a), and this time-based displacement data is, so to speak, coordinate data consisting of a combination of a "positioning time" and a "smoothed displacement" related to the positioning time. Therefore, the time-based displacement generating means 113 reads out the positioning time and the smoothed displacement from the positioning data storage means 120 to generate a time-based displacement data set. However, since the positioning data storage means 120 stores two or more types of smoothed displacement, the time-based displacement generating means 113 generates two or more types of time-based displacement data sets. In addition, the time-based displacement generating means 113 can also generate a "positioning time-smoothed displacement transition graph" by plotting a plurality of time-based displacement data on a coordinate system consisting of two axes, "time" and "displacement," as shown in FIG. 8(a).

[0041] (Time-specific temperature generation means) The time-based temperature generating means 114 is a means for generating a "time-based temperature data set." Here, the time-based temperature data set is configured to include multiple "time-based temperature data" as shown in FIG. 7(b), and this time-based temperature data is, so to speak, coordinate data consisting of a combination of "temperature measurement time" and "component temperature" related to the temperature measurement time. Therefore, the time-based temperature generating means 114 reads out the temperature measurement time and the component temperature from the component temperature storage means 121 to generate a time-based temperature data set. In addition, the time-based temperature generating means 114 can also generate a "temperature measurement time-component temperature transition graph" by plotting multiple time-based temperature data on a coordinate system consisting of two axes, "time" and "temperature," as shown in FIG. 8(b).

[0042] (Temperature-specific displacement generating means) The temperature-specific displacement generating means 105 is a means for generating a "temperature-specific displacement data set" based on the time-specific displacement data set and the time-specific temperature data set. Here, the temperature-specific displacement data set includes a plurality of "temperature-specific displacement data" as shown in FIG. 7(c), and this temperature-specific displacement data is, so to speak, coordinate data consisting of a combination of "component temperature" and "smooth displacement". However, since two or more types of time-specific displacement data sets are generated, the temperature-specific displacement generating means 105 generates two or more types of temperature-specific displacement data sets. Hereinafter, a procedure for the temperature-specific displacement generating means 105 to generate a temperature-specific displacement data set will be described with reference to FIG. 9. Note that this figure shows an example in which three types of time-specific displacement data sets are generated, which will be referred to as the "first time-specific displacement data set", the "second time-specific displacement data set", and the "third time-specific displacement data set", respectively.

[0043] First, the temperature-specific displacement generating means 105 reads the positioning time from the time-specific displacement data included in the first time-specific displacement data set, and extracts the time-specific temperature data having the same or closest temperature measurement time from the time-specific temperature data set. Next, the "smooth displacement" of the time-specific displacement data and the "component temperature" of the extracted time-specific temperature data set are combined to generate "temperature-specific displacement data". Then, the "first temperature-specific displacement data set" is generated by generating temperature-specific displacement data for all the time-specific displacement data included in the first time-specific displacement data set. In addition, by repeating the same procedure, that is, the "second temperature-specific displacement data set" is generated based on the second time-specific displacement data set and the time-specific temperature data set, and the "third temperature-specific displacement data set" is generated based on the third time-specific displacement data set and the time-specific temperature data set. In addition, the temperature-specific displacement generating means 105 can also generate a "component temperature-smooth displacement transition graph" by plotting multiple temperature-specific displacement data on a coordinate system consisting of two axes, "temperature" and "displacement", as shown in FIG. 8(c).

[0044] (Correlation value calculation means) The correlation value calculation means 106 is a means for calculating a "correlation value (e.g., correlation coefficient, coefficient of determination, etc.)" indicating the degree of correlation between the time-specific displacement data set and the temperature-specific displacement data set. However, when calculating this correlation value, the temperature-specific displacement data set to be combined with the time-specific displacement data set is a temperature-specific displacement data set generated based on the time-specific displacement data set. For example, when three types of time-specific displacement data sets, namely, a "first time-specific displacement data set", a "second time-specific displacement data set", and a "third time-specific displacement data set", are generated, as shown in FIG. 10, a "first correlation value" is calculated based on the first time-specific displacement data set and the first temperature-specific displacement data set, a "second correlation value" is calculated based on the second time-specific displacement data set and the second temperature-specific displacement data set, and a "third correlation value" is calculated based on the third time-specific displacement data set and the third temperature-specific displacement data set.

[0045] (Means for generating regression equation) The regression equation generating means 112 is a means for calculating a regression equation based on the time-specific displacement data set and the temperature-specific displacement data set. The regression equation can be a linear equation, a quadratic equation, or a cubic or higher order regression equation. However, similar to the calculation of the correlation value, when calculating this regression equation, the temperature-specific displacement data set to be combined with the time-specific displacement data set is the temperature-specific displacement data set generated based on the time-specific displacement data set. For example, when three types of time-specific displacement data sets, namely, the "first time-specific displacement data set", the "second time-specific displacement data set", and the "third time-specific displacement data set", are generated, as shown in FIG. 10, the "first regression equation" is calculated based on the first time-specific displacement data set and the first temperature-specific displacement data set, the "second regression equation" is calculated based on the second time-specific displacement data set and the second temperature-specific displacement data set, and the "third regression equation" is calculated based on the third time-specific displacement data set and the third temperature-specific displacement data set.

[0046] (Processing method selection means) The processing method selection means 107 is a means for selecting a "determined noise processing" from two or more types of noise processing used when obtaining two or more types of smooth displacement. Specifically, the maximum value among the multiple types of correlation values ​​(in the example of FIG. 10, the first correlation value to the third correlation value) calculated by the correlation value calculation means 106 is selected as a "maximum correlation value", and the noise processing related to the maximum correlation value is selected as a "determined noise processing". For example, when the "second correlation value" shown in FIG. 10 is selected as the "maximum correlation value", the noise processing (second noise processing) that is, so to speak, the origin of the second temperature-specific displacement data set and the second time-specific displacement data set is selected as the "determined noise processing".

[0047] (Displacement difference calculation means) The displacement difference calculation means 109 is a means for calculating a "displacement difference" which is the difference between the smoothed displacement and the temperature displacement. However, the smoothed displacement for calculating this displacement difference is a smoothed displacement obtained using decision noise processing. Also, the temperature displacement used here is a temperature displacement in which the smoothed displacement and the member temperature are common. Below, a procedure in which the displacement difference calculation means 109 reads out the smoothed displacement and the temperature displacement and then calculates the displacement difference will be described.

[0048] First, the displacement difference calculation means 109 refers to the temperature-specific displacement data set obtained by the decision noise processing, and reads out the smoothed displacement and the member temperature included in the temperature-specific displacement data. Next, the temperature displacement calculation means 108 reads out the temperature displacement calculated using the read-out member temperature as a condition. Then, the displacement difference is calculated from the read-out smoothed displacement and the temperature displacement. Note that this displacement difference may be a value obtained by subtracting the temperature displacement from the smoothed displacement, that is, a value with a positive or negative sign. The displacement difference calculation means 109 may be specified to calculate the displacement difference at the timing when the positioning means 101 calculates the observation point coordinates (i.e., the observation point displacement calculation means 103 or the smoothed displacement calculation means 104 executes the processing), or may be specified to calculate the displacement difference at the timing when two or more observation point coordinates (i.e., the smoothed displacements) are obtained. For example, when the positioning means 101 determines "static coordinates" by static positioning as observation point coordinates, the displacement difference calculation means 109 can calculate the displacement difference every hour (observation time of static positioning), or the displacement difference calculation means 109 can calculate the displacement difference every two hours (or every three hours or more).

[0049] (First warning output means) The first warning output means 110 is a means for outputting a warning (hereinafter referred to as "first warning") when an abnormal displacement difference is calculated for the target member. Specifically, the first warning output means 110 compares the displacement difference with a threshold value (hereinafter referred to as "displacement difference threshold value"), and outputs the first warning when the displacement difference exceeds (or becomes equal to or greater than) the displacement difference threshold value. At this time, the target member and the displacement difference can be output together with the first warning. Also, the first warning can be displayed on a display or other display means, or the first warning can be output by a voice, or in various other ways. Also, the displacement difference threshold value can be a predetermined one, or can be dynamically calculated by the threshold value calculation means 111.

[0050] (Threshold calculation means) The threshold calculation means 111 is a means for calculating a "displacement difference threshold" to which the first warning output means 110 refers. Hereinafter, a procedure for the threshold calculation means 111 to calculate the displacement difference threshold will be described with reference to FIG. 11. First, the threshold calculation means 111 reads out a plurality of displacement differences included in a section going back a predetermined period from the current positioning time (for example, the present). In the case of FIG. 11, the displacement differences included in a section going back 23 hours from the positioning time are read out. For example, if the positioning time is 11:00 on December 2nd, the displacement differences included in "12:00 on December 1st to 11:00 on December 2nd" are read out. Similarly, if the positioning time is 12:00 on December 2nd, the displacement differences included in "13:00 on December 1st to 12:00 on December 2nd" are read out. If the positioning time is 13:00 on December 2nd, the displacement differences included in "14:00 on December 1st to 13:00 on December 2nd" are read out. The threshold calculation means 111 then sets the displacement difference threshold by performing statistical processing on the read-out multiple displacement differences. For example, the standard deviation σ is calculated for the multiple displacement differences, and the standard deviation σ is multiplied by three (3σ) and set as the displacement difference threshold. Of course, when setting the displacement difference threshold, it is also possible to set it based on statistical processing values ​​such as variance, average value, median, and mode in addition to the standard deviation.

[0051] (RTK displacement calculation method) The RTK displacement calculation means 115 is a means for calculating the "RTK coordinates" of the observation point by performing baseline analysis on the reception data received by the receiver RC, and for calculating the displacement of the observation point based on the RTK coordinates (hereinafter referred to as "RTK displacement"). Specifically, the RTK displacement calculation means 115 calculates the difference between the "initial (at the time of installation) RTK coordinates" of the observation point and the "RTK coordinates based on the current positioning" as the RTK displacement. Note that since the RTK coordinates are three-dimensional coordinates, the RTK displacement obtained from the RTK coordinates at two times (initial and current) can also be obtained as a displacement vector having a magnitude (amount of displacement) and a direction (direction of displacement).

[0052] (RTK moving average calculation method) The RTK moving average calculation means 116 is a means for calculating a moving average value based on a plurality of RTK displacements as the "RTK moving average value". Hereinafter, with reference to FIG. 12, a procedure for the RTK moving average calculation means 116 to calculate the RTK moving average value will be described. First, the RTK moving average calculation means 116 reads out a plurality of displacements included in a section (hereinafter referred to as the "average target section") that goes back a predetermined period from a time of interest (hereinafter referred to as the "time of interest") such as the current positioning time (for example, the present). For example, in FIG. 12, the displacement difference included in the average target section that goes back 24 hours from the time of interest is read out. Then, the RTK moving average calculation means 116 calculates the average value of the plurality of displacement differences that have been read out, and sets this average value as the RTK moving average value. In addition, in this figure, the time of interest is set every second, that is, the RTK moving average value is calculated every second.

[0053] (RTK difference calculation means) The RTK difference calculation means 117 is a means for calculating the "RTK difference" which is the difference between the RTK moving average value and the temperature change. Hereinafter, the procedure by which the RTK difference calculation means 117 calculates the RTK difference using the RTK moving average value and the temperature change will be described. First, the RTK difference calculation means 117 reads out the time of interest when the RTK moving average value was calculated, and after referring to the time-specific temperature data set, extracts from the time-specific temperature data set the time-specific temperature data having the same or closest temperature measurement time as the time of interest. Next, the temperature change calculated by the temperature change calculation means 108 is read out using the component temperature of the extracted time-specific temperature data as a condition. Then, the RTK difference is calculated using the RTK moving average value and the read out temperature change. Note that this RTK difference should be a value obtained by subtracting the temperature change from the RTK moving average value, that is, a value with a positive or negative sign.

[0054] The RTK difference calculation means 117 can also calculate the difference between the RTK displacement and the temperature displacement at the time of interest as the "RTK difference". The time of interest in this case can be automatically set, for example, to the current time, or can be set to a time input by an operator. In this case, the RTK difference calculation means 117 first reads out the set time of interest, refers to the time-specific temperature data set, and extracts from the time-specific temperature data set the time-specific temperature data having the same or closest temperature measurement time as the time of interest. Next, the temperature displacement calculation means 108 reads out the temperature displacement calculated using the component temperature of the extracted time-specific temperature data as a condition. Then, the RTK difference is calculated using the RTK displacement and the read out temperature displacement. The RTK difference is preferably a value obtained by subtracting the temperature displacement from the RTK displacement, that is, a value with a positive or negative sign.

[0055] (Second warning output means) The second warning output means 118 is a means for outputting a warning (hereinafter referred to as a "second warning") when an abnormal displacement difference is calculated for the target member. Specifically, the second warning output means 118 compares the RTK difference with a threshold value (hereinafter referred to as an "RTK difference threshold value"), and outputs a second warning when the RTK difference exceeds (or becomes equal to or greater than) the RTK difference threshold value. At this time, the target member and the RTK difference can be output together with the second warning. In addition, the second warning can be displayed on a display means such as a display, or the second warning can be output by various methods, such as by outputting the second warning by voice. In addition, the RTK difference threshold value can be a predetermined one, or can be dynamically calculated by the RTK threshold value calculation means 119.

[0056] (RTK threshold calculation method) The RTK threshold calculation means 119 is a means for calculating the "RTK difference threshold" referred to by the second warning output means 118. Specifically, the RTK difference threshold is set by performing statistical processing on a plurality of RTK differences included in a section (for example, an average target section) going back a predetermined period from the previous focus time. Of course, the RTK difference threshold may be set based on a focus time before the current focus time, such as the focus time before last or the focus time before that, in addition to the previous focus time. For example, in the case of FIG. 12, if the "k+2th period" is the current focus time (December 2, 13:25:52), statistical processing can be performed on the RTK difference included in the average target section of the "k+1th period", or statistical processing can be performed on the RTK difference included in the average target section of the "kth period".

[0057] For example, the RTK threshold calculation means 119 can obtain the standard deviation σ for multiple displacement differences included in the average target section related to the previous time of interest, and set the standard deviation σ multiplied by three (3σ) as the displacement difference threshold. Of course, when setting the displacement difference threshold, it can also be set based on statistical processing values ​​such as variance, average value, median, and mode in addition to the standard deviation.

[0058] (Processing flow) The main processing of the bridge displacement monitoring system 100 of the present invention will be described in detail below with reference to Figures 13 and 14. Figure 13 is a flow diagram showing an example of the main processing flow until the bridge displacement monitoring system 100 of the present invention determines the "displacement difference," and Figure 14 is a flow diagram showing an example of the main processing flow until the bridge displacement monitoring system 100 of the present invention determines the "RTK difference." In these figures, the center column shows the processing to be performed, the left column shows what is necessary for that processing, and the right column shows what results from that processing.

[0059] When the bridge displacement monitoring system 100 judges the displacement difference, first, as shown in Fig. 13, the receiver RC repeatedly receives the received data, and the temperature measurement means 102 measures the "component temperature" of the target component (Step 201 in Fig. 13). When the component temperature of the target component is obtained, the temperature displacement calculation means 108 performs a structural analysis using the component temperature as a condition to calculate the temperature displacement of the target component (Step 202 in Fig. 13). In addition, the positioning means 101 obtains the "static coordinates" of the observation point, for example, by performing a baseline analysis on the received data (Step 203 in Fig. 13). Next, the observation point displacement calculation means 103 calculates the difference between the "initial (installation) static coordinates" of the observation point and the "static coordinates based on the current positioning" as the observation point displacement (Step 204 in Fig. 13).

[0060] When the observation point displacement is obtained, the smoothed displacement calculation means 104 performs two or more types of noise processing on the observation point displacement to obtain two or more types of smoothed displacement (Step 205 in FIG. 13). When two or more types of smoothed displacement are obtained, the time-specific displacement generation means 113 generates two or more types of "time-specific displacement data set", the time-specific temperature generation means 114 generates a "time-specific temperature data set", and the temperature-specific displacement generation means 105 generates two or more types of "temperature-specific displacement data set" based on the time-specific displacement data set and the time-specific temperature data set (Step 206 in FIG. 13).

[0061] When two or more types of temperature-specific displacement data sets are obtained, the correlation value calculation means 106 calculates two or more types of correlation values, and the regression equation generation means 112 calculates two or more types of regression equations (Step 207 in FIG. 13). The processing method selection means 107 selects the "maximum correlation value" and then selects the noise processing associated with the maximum correlation value as the "determined noise processing" (Step 208 in FIG. 13).

[0062] When the determination noise processing is selected, the displacement difference calculation means 109 calculates the "displacement difference" which is the difference between the smoothed displacement and the temperature displacement (Step 209 in FIG. 13). As described above, the smoothed displacement for calculating this displacement difference is the smoothed displacement obtained using the determination noise processing. Meanwhile, the threshold calculation means 111 calculates the "displacement difference threshold" which the first warning output means 110 refers to (Step 210 in FIG. 13). Then, the first warning output means 110 checks the displacement difference against the displacement difference threshold, and when the displacement difference exceeds (or becomes equal to or greater than) the displacement difference threshold, it outputs the first warning (Step 211 in FIG. 13). Meanwhile, when the displacement difference becomes equal to or less than (or falls below) the displacement difference threshold, it continues to perform various measurements (Step 201 in FIG. 13).

[0063] When the bridge displacement monitoring system 100 judges the RTK difference, first, as shown in FIG. 14, the RTK displacement calculation means 115 performs baseline analysis on the received data to obtain the "RTK coordinates" of the observation point (Step 212 in FIG. 14). Next, the RTK moving average calculation means 116 calculates the moving average value based on the multiple RTK displacements included in the average target section as the "RTK moving average value" (Step 213 in FIG. 14). Once the RTK moving average value is obtained, the RTK difference calculation means 117 calculates the "RTK difference" which is the difference between the RTK moving average value and the temperature displacement (Step 214 in FIG. 14). Meanwhile, the RTK threshold calculation means 119 calculates the "RTK difference threshold value" referenced by the first warning output means 110 (Step 215 in FIG. 14). Then, the second warning output means 118 compares the RTK difference with the RTK difference threshold, and if the RTK difference exceeds (or is equal to or greater than) the RTK difference threshold, it outputs a second warning (Step 216 in FIG. 14). On the other hand, if the RTK difference is equal to or less than (or is below) the RTK difference threshold, it continues to perform various measurements (Step 201 in FIG. 13). [Industrial Applicability]

[0064] The bridge displacement monitoring system of the present invention can be used for various bridges, such as concrete bridges, steel bridges, etc. Considering that it can detect abnormalities in bridges, which are construction infrastructure, in advance and prevent accidents caused by bridge damage, the present invention can be said to be an invention that can be expected to not only be used industrially but also to make a great contribution to society. [Explanation of symbols]

[0065] 100 Bridge displacement monitoring system of the present invention 101 (Bridge Displacement Monitoring System) Positioning Means 102 Temperature measurement means (for bridge displacement monitoring system) 103 (Bridge Displacement Monitoring System) Observation Point Displacement Calculation Method 104 (Bridge Displacement Monitoring System) Smooth Displacement Calculation Method 105 (Bridge Displacement Monitoring System) Temperature-Specific Displacement Generation Method 106 (Bridge displacement monitoring system) correlation value calculation means 107 (Bridge Displacement Monitoring System) Processing Method Selection Method 108 (Bridge Displacement Monitoring System) Temperature Displacement Calculation Method 109 (Bridge Displacement Monitoring System) Displacement Difference Calculation Method 110 (of bridge displacement monitoring system) first warning output means 111 (Bridge displacement monitoring system) threshold calculation means 112 (Bridge displacement monitoring system) regression equation generation means 113 (Bridge Displacement Monitoring System) Time-Specific Displacement Generation Method 114 (Bridge displacement monitoring system) Time-specific temperature generation means 115 (Bridge Displacement Monitoring System) RTK Displacement Calculation Method 116 (Bridge displacement monitoring system) RTK moving average calculation method 117 (Bridge Displacement Monitoring System) RTK Differential Calculation Method 118 (of bridge displacement monitoring system) second warning output means 119 (Bridge displacement monitoring system) RTK threshold calculation method 120 (Bridge displacement monitoring system) positioning data storage means 121 (Bridge displacement monitoring system) Component temperature storage means 122 (Bridge displacement monitoring system) 3D model storage means RC Receiver ST positioning satellite

Claims

1. A system for monitoring bridge displacement, comprising: a positioning means for acquiring observation point coordinates by repeatedly measuring the position of an observation point disposed on a target member of the bridge using a positioning satellite; a temperature measuring means for acquiring a temperature of the target component by repeatedly measuring the temperature of the target component; an observation point displacement calculation means for calculating an observation point displacement of the observation point based on the observation point coordinates; a smoothed displacement calculation means for performing two or more different types of noise processing on the plurality of observation point displacements to obtain two or more types of smoothed displacements; a temperature-based displacement generating means for generating two or more types of temperature-based displacement data sets based on the time-based temperature data set and two or more types of time-based displacement data sets; a correlation value calculation means for calculating a correlation value indicating a degree of correlation between the time-based displacement data set and the temperature-based displacement data set generated based on the time-based displacement data set; a processing method selection means for selecting a maximum correlation value indicating the largest value among the correlation values ​​calculated by the correlation value calculation means, and selecting, from two or more types of noise processing, the noise processing associated with the maximum correlation value as a determined noise processing; a temperature displacement calculation means for calculating a temperature displacement of the target member by performing a structural analysis under a temperature condition; a displacement difference calculation means for calculating a displacement difference between the smooth displacement and the temperature displacement; a first warning output means for comparing the displacement difference with a displacement difference threshold and outputting a warning when the displacement difference exceeds the displacement difference threshold, The time-based temperature data set includes a plurality of time-based temperature data; The time-based displacement data set includes a plurality of time-based displacement data, The temperature-specific displacement data set includes a plurality of temperature-specific displacement data, The time-based temperature data is composed of a combination of a temperature measurement time measured by the temperature measuring means and the member temperature associated with the temperature measurement time, the time-based displacement data is composed of a combination of a positioning time at which the positioning means measures the position and the smoothed displacement associated with the positioning time, The temperature-specific displacement data is a combination of the member temperature and the smooth displacement, the temperature-based displacement generating means generates the temperature-based displacement data set by combining the member temperature with the smoothed displacement related to the positioning time that is the same as or close to the temperature measurement time related to the member temperature; The displacement difference calculation means calculates the displacement difference between the observation point displacement and the temperature displacement between the same member temperatures based on the temperature-specific displacement data set related to the determination noise processing. A bridge displacement monitoring system comprising:

2. the observation point displacement calculation means performs a baseline analysis to obtain static coordinates of the observation point based on static positioning, and obtains static displacements of the observation point based on the static coordinates; 2. The bridge displacement monitoring system according to claim 1.

3. The method further includes: the threshold calculation means calculates the displacement difference threshold by performing statistical processing on the plurality of displacement differences calculated by the displacement difference calculation means; The first warning output means compares the displacement difference with the displacement difference threshold value calculated by the threshold value calculation means.

3. The bridge displacement monitoring system according to claim 1 or 2.

4. The method further includes a regression equation generating means for generating a regression equation based on the time-variant displacement data set and the temperature-variant displacement data set generated based on the time-variant displacement data set.

3. The bridge displacement monitoring system according to claim 1 or 2.

5. an RTK displacement calculation means for calculating an RTK coordinate of the observation point based on real-time kinematic positioning by performing a baseline analysis, and for calculating an RTK displacement related to the observation point based on the RTK coordinate; An RTK moving average calculation means for calculating an RTK moving average value which is an average value of a plurality of the RTK displacements included in an average target section going back a certain period from a time of interest; an RTK difference calculation means for calculating an RTK difference, which is a difference between the RTK moving average value and the temperature change calculated by the temperature change calculation means based on the member temperature related to the temperature measurement time that is the same as or close to the time of interest related to the RTK moving average value; A second warning output means for comparing the RTK difference with an RTK difference threshold and outputting a warning when the RTK difference exceeds the RTK difference.

2. The bridge displacement monitoring system according to claim 1.

6. an RTK displacement calculation means for calculating an RTK coordinate of the observation point based on real-time kinematic positioning by performing a baseline analysis, and for calculating an RTK displacement related to the observation point based on the RTK coordinate; an RTK difference calculation means for calculating an RTK difference between the RTK difference at a time of interest and the temperature difference calculated by the temperature difference calculation means based on the member temperature related to the temperature measurement time that is the same as or close to the time of interest; A second warning output means for comparing the RTK difference with an RTK difference threshold and outputting a warning when the RTK difference exceeds the RTK difference threshold.

2. The bridge displacement monitoring system according to claim 1.

7. Further comprising an RTK threshold calculation means for calculating the RTK difference threshold, the RTK threshold calculation means calculates the RTK difference threshold by performing statistical processing on a plurality of the RTK differences included in a section preceding the target time by a predetermined period; The second warning output means compares the RTK difference with the RTK difference threshold value based on the time of interest that is earlier than the time of interest related to the RTK difference.

7. The bridge displacement monitoring system according to claim 5 or 6.

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