Displacement measurement system

Abstract

To provide a displacement measurement system that automatically measures the displacement of a tunnel wall surface in three-dimensional coordinates with high accuracy.SOLUTION: A displacement measurement system includes first reference devices 111-113 and first measurement devices 211-213. Each of the first reference devices can acquire position coordinates of its own device with high accuracy. Each first reference device is placed near a first entrance / exit W1 of a tunnel 90, and performs optical ranging over a ranging range that includes the inside of the tunnel to generate first feature point data. The first reference devices are capable of communicating with each other. Each of the first measurement devices is placed within the ranging range of the first reference devices in the tunnel. The first measurement device performs optical ranging over a ranging range on the opposite side of the first reference device to generate second feature point data. The first measurement devices are capable of communicating with the first reference devices. The first reference device of a master station generates point cloud data from the first feature point data and the second feature point data to which optical ranging time is attached.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for measuring the displacement of an inner wall surface, such as the displacement of a tunnel wall surface. [Background technology]

[0002] Conventionally, methods for measuring indoor displacement as shown in Patent Documents 1 and 2 are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3659069 [Patent Document 2] Patent No. 3737455 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional displacement measurement methods did not provide a way to automatically measure the displacement of a tunnel wall, which changes gradually over a long period of time, with high accuracy in three-dimensional coordinates.

[0005] Therefore, an object of the present invention is to automatically measure the displacement of a tunnel wall surface in three-dimensional coordinates with high accuracy. [Means for solving the problem]

[0006] The displacement measurement system of the present invention includes a plurality of first reference devices, a plurality of first measuring devices, and an analysis unit. Each of the plurality of first reference devices is capable of acquiring its own position coordinates with high accuracy. The plurality of first reference devices are disposed near a first entrance / exit of the tunnel, and each performs optical ranging within a ranging range including the inside of the tunnel to generate a plurality of first feature point data. The plurality of first reference devices are capable of communicating with each other. The plurality of first measuring devices are disposed within the ranging ranges of the plurality of first reference devices in the tunnel. The plurality of first measuring devices perform optical ranging with the opposite side of the plurality of first reference devices as the ranging range to generate a plurality of second feature point data. The plurality of first measuring devices are capable of communicating with at least one of the plurality of first reference devices.

[0007] The multiple first reference devices include a master station and at least two slave stations. The first reference device of the master station generates time synchronization information based on time reference information. The first reference device of the slave station performs time synchronization control based on the time synchronization information or the time reference information obtained by the first reference device. The multiple first measurement devices perform time synchronization control based on the time synchronization information.

[0008] The first reference devices attach optical ranging times based on the time synchronization information to the first feature data, and the first measurement devices attach optical ranging times based on the time synchronization information to the second feature data.

[0009] The first reference device of the master station generates point cloud data from the first feature data and the second feature data, to which the optical ranging time is attached.

[0010] In this configuration, the multiple first reference devices know their own positions with high accuracy, and the multiple first measuring devices know their own positions with high accuracy because they are within the distance measurement ranges of the multiple first reference devices. The multiple first reference devices and the multiple first measuring devices are time-synchronized by time synchronization information, making it possible to time-synchronize the first feature data and second feature data measured by each of them.

[0011] In addition, the optical distance measuring ranges of the first measurement devices include a range that is deeper into the tunnel than the optical distance measuring ranges of the first reference devices, but does not include the optical distance measuring ranges of the first reference devices. This allows a wider range inside the tunnel to be measured than simply optical distance measuring with the first reference devices.

[0012] The displacement measuring system of the present invention includes an analysis device that measures the displacement of a wall surface in a tunnel based on a plurality of first feature data and a plurality of second feature data.

[0013] The analysis device sets a plurality of grid points that are arranged two-dimensionally at a predetermined interval in correspondence with the wall surface of the tunnel. The analysis device calculates the three-dimensional coordinates of the plurality of grid points at a plurality of times based on the light ranging time using the first point cloud data at the same time. The analysis device measures the displacement of the wall surface of the tunnel based on the three-dimensional coordinates of the plurality of grid points at the plurality of times.

[0014] In this configuration, the analysis device can measure displacement over a wide range inside the tunnel by using the first feature data and the second feature data obtained in this manner. In this case, the positions of the first feature data and the second feature data are not necessarily aligned at equal intervals. Therefore, the analysis unit sets a two-dimensional array of grid points corresponding to the wall surface of the tunnel, and measures the three-dimensional displacement of each grid point based on the first feature data and the second feature data.

[0015] This enables the displacement measurement system to automatically measure the displacement of the tunnel wall surface in three-dimensional coordinates with high precision. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing an example of a device configuration of a displacement measuring system according to the first embodiment. [Diagram 2] FIG. 2(A) is a partial cross-sectional plan view of a tunnel showing a measurement example of the displacement measurement system according to the first embodiment, and FIG. 2(B) is a partial cross-sectional plan view of a tunnel showing a communication example of the displacement measurement system according to the first embodiment. [Diagram 3] FIG. 3 is a partial cross-sectional side view of a tunnel showing an example of the device configuration of the displacement measuring system according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a functional block of the master station master device. [Diagram 5] FIG. 5 is a diagram illustrating an example of a functional block of a master device of a slave station. [Figure 6] FIG. 6 is a diagram illustrating an example of functional blocks of the measurement device. [Figure 7] FIG. 7(A) is a diagram showing an example of a functional block of an analysis device, and FIG. 7(B) is a diagram showing an example of a functional block of a displacement measuring unit. [Figure 8] FIG. 8 is a diagram showing an example of setting grid points. [Figure 9] FIG. 9 is a flowchart showing an example of a system flow of the displacement measuring method according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a functional block diagram of the measurement apparatus according to the second embodiment. [Figure 11] FIG. 11 is a timing chart showing an example of processing of the master station reference device, the slave station reference device, and the measurement device of the displacement measuring system according to the second embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of a system flow of the displacement measuring method according to the second embodiment of the present invention. [Figure 13] FIG. 13 is a flowchart showing an example of a system flow of the displacement measuring method according to the second embodiment of the present invention. [Figure 14] FIG. 14 is a perspective view showing a device configuration of a displacement measuring system according to the third embodiment. [Figure 15] FIG. 15 is a perspective view showing a device configuration of a displacement measuring system according to the fourth embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of a functional block of the master device of the master station in the first derivative example. [Figure 17] FIG. 17 is a diagram illustrating an example of a functional block of the master device of the master station in the derivative example 2. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [First embodiment] A displacement measurement system and a displacement measurement method according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of a device configuration of the displacement measurement system according to the first embodiment. FIG. 2(A) is a partial plan sectional view of a tunnel showing a measurement example of the displacement measurement system according to the first embodiment, and FIG. 2(B) is a partial plan sectional view of a tunnel showing a communication example of the displacement measurement system according to the first embodiment. FIG. 3 is a partial side sectional view of a tunnel showing an example of the device configuration of the displacement measurement system according to the first embodiment.

[0018] In this embodiment, the wall surface of a tunnel is the target of displacement measurement. However, the configuration of the present invention can also be applied to displacement measurement in places where GNSS positioning signals cannot be received or are difficult to receive, such as underground shopping malls.

[0019] (Device configuration of displacement measurement system) 1, 2(A), 2(B), and 3, the displacement measurement system includes a plurality of reference devices 111-113 (reference device 111, reference device 112, reference device 113), a plurality of measuring devices 211-213 (measuring device 211, measuring device 212, measuring device 213), a plurality of measuring devices 221-223 (measuring device 221, measuring device 222, measuring device 223), a plurality of measuring devices 231-233 (measuring device 231, measuring device 232, measuring device 233), a plurality of measuring devices 241-243 (measuring device 241, measuring device 242, measuring device 243), an analysis device 81, and a network 800 for data communication. The reference device 111, the reference device 112, and the reference device 113 correspond to the "first reference device", and the measuring device 211, the measuring device 212, and the measuring device 213 correspond to the "first measuring device". The measuring instrument 221, the measuring instrument 222, the measuring instrument 223, the measuring instrument 231, the measuring instrument 232, the measuring instrument 233, the measuring instrument 241, the measuring instrument 242, and the measuring instrument 243 correspond to the "second measuring instrument".

[0020] The reference device 111, the reference device 112, and the reference device 113 are disposed outside the first entrance / exit EW1 of the tunnel 90 (for example, near the shoulder of the road 91 passing through the tunnel 90). The reference device 111, the reference device 112, and the reference device 113 are disposed in an environment (open sky environment) where they can receive positioning signals from positioning satellites of the GNSS (Global Navigation Satellite Systems) (for example, GPS satellites of the GPS (Global Positioning System)). The reference device 111, the reference device 112, and the reference device 113 are disposed so that all three of these devices can optically measure the distances to all of the measurement devices 221-223.

[0021] The number of reference devices is not limited to three, and may be any number equal to or greater than three. Reference device 111, reference device 112, and reference device 113 may be disposed near the first entrance / exit EW1 of tunnel 90 as long as they can receive positioning signals.

[0022] As shown in FIGS. 1, 2(A), 2(B), and 3, a plurality of measuring devices 211-213, a plurality of measuring devices 221-223, a plurality of measuring devices 231-233, and a plurality of measuring devices 241-243 are installed on a wall surface 900 of a tunnel 90.

[0023] The tunnel 90 includes a first entrance EW1 and a second entrance EW2. On a wall surface 900 of the tunnel 90, a plurality of measurement devices 211-213, a plurality of measurement devices 221-223, a plurality of measurement devices 231-233, and a plurality of measurement devices 241-243 are arranged at intervals in this order from the first entrance EW1 to the second entrance EW2.

[0024] The distances of the multiple measurement devices 211-213 from the first entrance EW1 are approximately the same. The multiple measurement devices 211-213 are disposed at positions where data communication with any of the multiple reference devices 111-113 is possible within the optical distance measurement ranges of the multiple reference devices 111-113.

[0025] The distances from the first entrance EW1 to the multiple measurement instruments 221-223 are approximately the same. The multiple measurement instruments 221-223 are disposed at positions where data communication with any of the multiple measurement instruments 211-213 is possible within the optical distance measurement ranges of the multiple measurement instruments 211-213.

[0026] The distances from the first entrance EW1 to the multiple measurement devices 231-233 are approximately the same. The multiple measurement devices 231-233 are disposed at positions where data communication with any of the multiple measurement devices 221-223 is possible within the optical distance measurement ranges of the multiple measurement devices 221-223.

[0027] The distances from the first entrance EW1 to the multiple measurement devices 241-243 are approximately the same. The multiple measurement devices 241-243 are disposed at positions where data communication with any of the multiple measurement devices 231-233 is possible within the optical distance measurement ranges of the multiple measurement devices 231-233.

[0028] Note that a plurality of measurement devices arranged at approximately the same position is regarded as a measurement device group, and the number of measurement device groups can be appropriately set according to the length of the tunnel 90 (the size of the target object) and the intervals at which the plurality of measurement devices are arranged. Also, the number of measurement devices constituting a measurement device group can be appropriately set.

[0029] Reference device 111 can communicate with analysis device 81 through network 800. Network 800 may be a wired communication network, a wireless communication network, or a mixed communication network using wired and wireless communication.

[0030] (Reference device 111-113) Of the multiple reference devices 111-113, the reference device 111 serves as a master station, and the reference devices 112 and 113 serve as slave stations.

[0031] (Reference device 111) FIG. 4 is a diagram illustrating an example of functional blocks of the master station according to the first embodiment.

[0032] 4, the master station reference device 111 includes a GNSS antenna 1110, a GNSS receiver 1111, a synchronization control unit 1112, a distance measurement control unit 1113, an optical distance measurement unit 1114, a feature point data generation unit 1115, a measurement data processing unit 1116, a point cloud data communication unit 1118, and a communication unit 1119. Note that the power supply is not shown in the figure.

[0033] The GNSS antenna 1110 receives a GNSS positioning signal (for example, a GPS signal) and outputs it to the GNSS receiver 1111. The GNSS receiver 1111 uses the GNSS positioning signal to measure the position coordinates of the reference device 111. In this case, it is preferable that the GNSS receiver 1111 performs positioning using the carrier phase of the GNSS positioning signal. By using the carrier phase, the GNSS receiver 1111 can measure the position coordinates of the reference device 111 with higher accuracy.

[0034] The GNSS receiver 1111 time-synchronizes the internal clock of the GNSS receiver 1111 with an arbitrary time system such as UTC using time reference information obtained from a navigation message of the GNSS positioning signal, and generates a 1PPS signal. The GNSS receiver 1111 outputs the time information (time rounded down to the nearest second) and the 1PPS signal to the synchronization control unit 1112.

[0035] The synchronization control unit 1112 generates a time count value smaller than one second calculated based on the 1PPS signal. The synchronization control unit 1112 performs time synchronization between the reference device 111 and the other reference devices 112 and 113 and the multiple measurement devices 211-213, 221-223, 231-233, and 241-243, using time synchronization information (precise time including less than a second obtained from the time information and the time count value). A specific method of time synchronization will be described later.

[0036] The synchronization control unit 1112 outputs the time-synchronized precise time to the distance measurement control unit 1113 .

[0037] The synchronization control unit 1112 outputs the time-synchronized precise time as a time tag TIMETAG to the feature point data generation unit 1115.

[0038] The distance measurement control unit 1113 generates a distance measurement timing signal by referring to the time-synchronized precise time, and outputs the distance measurement timing signal to the optical distance measurement unit 1114 .

[0039] The optical distance measuring unit 1114 is, for example, a LIDAR. The optical distance measuring unit 1114 performs three-dimensional distance measurement in synchronization with a distance measurement timing signal. The optical distance measuring unit 1114 outputs distance measurement data by the three-dimensional distance measurement to the feature point data generating unit 1115.

[0040] The feature data generating unit 1115 generates feature data from the distance measurement data. The feature data is extracted as the position and feature point (see Pm in FIG. 3) where a predetermined light receiving level is exceeded in the distance measurement data, and is expressed as three-dimensional position coordinates (distance and direction) based on the position coordinates of the reference device 111 and the received signal intensity. The feature data generated by the feature data generating unit 1115 corresponds to a part of the "first feature data" of the present invention.

[0041] Furthermore, the feature data generation unit 1115 assigns a time tag (TIMETAG in FIG. 4) of the distance measurement timing from the synchronization control unit 1112 to the feature data. The feature data generation unit 1115 outputs the feature data with the time tag (DATAm111 in FIG. 4) to the measurement data processing unit 1116.

[0042] The measurement data processing unit 1116 generates point cloud data which is a collection of time-tagged feature point data obtained from the feature point data generation unit 1115 and time-tagged feature point data (DATAr111 in FIG. 4) obtained from other devices via the communication unit 1119. The measurement data processing unit 1116 outputs the point cloud data to the point cloud data communication unit 1118.

[0043] The point cloud data communication unit 1118 transmits the point cloud data to the analysis device 81 through the network 800.

[0044] During time synchronization control, the communication unit 1119 communicates various data related to time synchronization with the communication units of the other master devices 112 and 113 and at least the measurement devices 211-213.

[0045] During measurement and data communication, the communication unit 1119 receives time-tagged feature data (time-tagged first feature data) from the other reference devices 112, 113, and time-tagged feature data (time-tagged second feature data) from at least the measuring devices 211-213. The communication unit 1119 outputs the received time-tagged feature data to the measurement data processing unit 1116.

[0046] (Reference device 112, 113) Fig. 5 is a diagram showing an example of a functional block of a master device of a slave station according to the first embodiment. In Fig. 5, the master device 112 is shown as an example, but the master device 112 and the master device 113 have the same basic configuration, and therefore only the master device 112 will be described.

[0047] 5, the slave station reference device 112 includes a GNSS antenna 1120, a GNSS receiver 1121, a synchronization control unit 1122, a distance measurement control unit 1123, an optical distance measurement unit 1124, a feature point data generation unit 1125, a measurement data processing unit 1126, and a communication unit 1129. Note that a power supply is not shown in the figure.

[0048] The GNSS antenna 1120 receives a GNSS positioning signal (for example, a GPS signal) and outputs it to the GNSS receiver 1121. The GNSS receiver 1121 uses the GNSS positioning signal to measure the position coordinates of the reference device 112. In this case, it is preferable that the GNSS receiver 1121 performs positioning using the carrier phase of the GNSS positioning signal. By using the carrier phase, the GNSS receiver 1121 can measure the position coordinates of the reference device 112 with higher accuracy.

[0049] The synchronization control unit 1122, like the reference unit 111, performs time synchronization between the reference unit 111 and the other reference units 113 and the multiple measurement units 211-213, 221-223, 231-233, and 241-243, using time synchronization information based on the 1PPS signal generated by the GNSS receiver 1121. The synchronization control unit 1122 can also perform time synchronization using the time synchronization information from the reference unit 111.

[0050] The synchronization control unit 1122 outputs the time-synchronized precise time to the distance measurement control unit 1123. The synchronization control unit 1122 outputs the time-synchronized precise time to the feature point data generation unit 1125 as a time tag.

[0051] The distance measurement control unit 1123 generates a distance measurement timing signal by referring to the time-synchronized precise time, and outputs the distance measurement timing signal to the optical distance measurement unit 1124 .

[0052] The optical distance measuring unit 1124 is, for example, a LIDAR. The optical distance measuring unit 1124 performs three-dimensional distance measurement in synchronization with a distance measurement timing signal. The optical distance measuring unit 1124 outputs distance measurement data by the three-dimensional distance measurement to the feature point data generating unit 1125.

[0053] The feature data generating unit 1125 generates feature data from the distance measurement data. The feature data is extracted as a position and feature point where a predetermined light receiving level is exceeded in the distance measurement data, and is expressed by three-dimensional position coordinates (distance and direction) and received signal intensity based on the position coordinates of the reference device 112. The feature data generated by the feature data generating unit 1125 corresponds to a part of the "first feature data" of the present invention.

[0054] Furthermore, the feature data generation unit 1125 assigns a time tag (TIMETAG in FIG. 5) of the distance measurement timing to the feature data from the synchronization control unit 1122. The feature data generation unit 1125 outputs the feature data with the time tag (DATAm112 in FIG. 5) to the measurement data processing unit 1126.

[0055] The measurement data processing unit 1126 generates point cloud data (DATAcl112 in FIG. 5) which is a collection of time-tagged feature point data obtained from the feature point data generation unit 1125 and time-tagged feature point data (DATAr112 in FIG. 5) obtained from other measurement devices with which the reference device 112 can communicate via the communication unit 1129. The measurement data processing unit 1126 outputs the point cloud data to the communication unit 1129.

[0056] During time synchronization control, the communication unit 1129 communicates various data related to time synchronization with the communication units of the other master devices 111 and 113 and at least the measurement devices 211-213.

[0057] During measurement and data communication, the communication unit 1129 receives time-tagged feature point data (second time-tagged feature point data) from other measurement devices with which the reference device 112 can communicate. The communication unit 1129 outputs the received time-tagged feature point data to the measurement data processing unit 1126. The communication unit 1129 transmits point cloud data generated by its own device (a collection of time-tagged feature point data generated by its own device and time-tagged feature point data received from other measurement devices) to the communication unit 1119 of the reference device 111.

[0058] (Measuring equipment 211-213, 221-223, 231-233, 241-243) Fig. 6 is a diagram showing an example of functional blocks of the measuring device according to the first embodiment. In Fig. 6, the measuring device 211 is shown as an example, but the basic configurations of the measuring devices 211-213, 221-223, 231-233, and 241-243 are similar, so only the measuring device 211 will be described.

[0059] 6, the measurement device 211 includes a synchronization control unit 2112, a distance measurement control unit 2113, an optical distance measurement unit 2114, a feature point data generation unit 2115, a measurement data processing unit 2116, and a communication unit 2119. Note that a power supply is not shown in the figure.

[0060] The synchronization control unit 2112 performs time synchronization with the reference devices 111-113 and other measurement devices using the time synchronization information from the reference device 111. The synchronization control unit 2112 outputs the time-synchronized precise time to the distance measurement control unit 2113. The synchronization control unit 2112 outputs the time-synchronized precise time to the feature point data generation unit 2115 as a time tag.

[0061] The distance measurement control unit 2113 generates a distance measurement timing signal with reference to the time-synchronized precise time, and outputs the distance measurement timing signal to the optical distance measurement unit 2114 .

[0062] The optical distance measuring unit 2114 is, for example, a LIDAR. The optical distance measuring unit 2114 performs three-dimensional distance measurement in synchronization with a distance measurement timing signal. The optical distance measuring unit 2114 outputs distance measurement data by the three-dimensional distance measurement to the feature point data generating unit 2115.

[0063] The feature data generating unit 2115 generates feature data from the distance measurement data. The feature data is extracted as a position and feature point where a predetermined light receiving level is exceeded in the distance measurement data, and is expressed by three-dimensional position coordinates (distance and direction) and received signal intensity based on the position coordinates of the measuring device 211. The feature data generated by the feature data generating unit 2115 corresponds to a part of the "second feature data" of the present invention.

[0064] Furthermore, the feature data generation unit 2115 assigns a time tag (TIMETAG in FIG. 6) of the distance measurement timing from the synchronization control unit 2112 to the feature data. The feature data generation unit 2115 outputs the feature data with the time tag (DATAm 211 in FIG. 6) to the measurement data processing unit 2116.

[0065] The measurement data processing unit 2116 generates point cloud data (DATAcl211 in FIG. 6) which is a collection of time-tagged feature point data obtained from the feature point data generation unit 2115 and time-tagged feature point data (DATAr211 in FIG. 6) obtained from other measurement devices with which the measurement device 211 can communicate via the communication unit 2119. The measurement data processing unit 2116 outputs the point cloud data to the communication unit 2119.

[0066] During time synchronization control, the communication unit 2119 communicates various data related to time synchronization with at least one of the reference devices 111-113 and the communication units of the measurement devices 221-223.

[0067] During measurement and data communication, the communication unit 2119 receives time-tagged feature point data (second time-tagged feature point data) from other measurement devices with which the measurement device 211 can communicate (measurement devices farther from the first entrance / exit EW1). The communication unit 2119 outputs the received time-tagged feature point data to the measurement data processing unit 2116. The communication unit 2119 transmits point cloud data generated by its own device (a collection of time-tagged feature point data generated by its own device and time-tagged feature point data received from other measurement devices) to the communication unit of one of the multiple reference devices 111-113.

[0068] During measurement and data communication, the multiple measuring devices 221-223 receive time-tagged feature point data (second time-tagged feature point data) from other measuring devices with which they can communicate (measurement devices farther from the first entrance / exit EW1). The multiple measuring devices 221-223 transmit point cloud data, which is a collection of the time-tagged feature point data measured by the multiple measuring devices themselves and the received time-tagged feature point data, to a communication unit of one of the multiple measuring devices 211-213.

[0069] During measurement and data communication, the multiple measuring devices 231-233 receive time-tagged feature point data (second time-tagged feature point data) from other measuring devices with which they can communicate (measuring devices 241-243 on the far side from the first entrance / exit EW1). The multiple measuring devices 231-233 transmit point cloud data, which is a collection of the time-tagged feature point data measured by the multiple measuring devices themselves and the received time-tagged feature point data, to a communication unit of one of the multiple measuring devices 221-223.

[0070] Note that the multiple measurement devices (eg, multiple measurement devices 241-243 in FIG. 1) at the end of data communication do not require a measurement data processing unit, and feature data is output from the feature data generation unit to the communication unit.

[0071] (Time Synchronization Control) The synchronization control unit 1112 of the master station master 111 and the master stations 112, 113 and the measuring devices 211-213, 221-223, 231-233, 241-243 perform time synchronization by, for example, the PTP method. Specifically, the time synchronization is performed, for example, as follows.

[0072] The synchronization control unit 1112 of the master station master device 111 includes a phase comparator, an internal oscillator, an NCO, a loop filter, a frequency divider, a precise time determination unit, and a first synchronization processing unit.

[0073] The phase comparator calculates the phase difference between the 1PPS signal and a replica signal of the 1PPS signal output from the frequency divider, and outputs it to the loop filter. The loop filter continuously generates a frequency signal so that the phase difference gradually approaches 0 (zero), and outputs it to the NCO. The NCO generates a clock signal with a frequency that is an integer fraction of 1 second from the output of the loop filter (a frequency signal according to the phase difference) and the output of the internal oscillator (a predetermined frequency signal), and outputs it to the frequency divider. The frequency divider divides the clock signal and outputs a time count value less than a second to the precise time determination unit. When the phase difference information from the phase comparator approaches zero due to the operation of the phase-locked loop that brings the phase difference closer to zero, the frequency divider, which is part of the precision clock, is synchronized with the 1PPS signal and is synchronized with the time system of the GNSS. The precise time determination unit determines the precise time including fractions of a second (digits finer than a second) from the time of seconds or more and the time count value less than a second, and outputs it to the first synchronization processing unit.

[0074] The first synchronization processing unit transmits the precise time to a second synchronization processing unit (described later) of the other device, receives the reception time and reply time of the transmitted precise time from the second synchronization processing unit, and calculates the time error of the other device from these times and transmits it to this device.

[0075] The synchronization control units of the plurality of reference devices 112, 113 and the plurality of measuring devices 211-213, 221-223, 231-233, 241-243 include an internal oscillator, an NCO, a loop filter, a first frequency divider, a second frequency divider, and a second synchronization processing unit.

[0076] The loop filter generates a frequency signal corresponding to the phase difference (less than a second in the time error) from the second synchronization processing unit and outputs it to the NCO. The NCO generates a clock signal with a frequency that is an integer fraction of a second from the output of the loop filter (a frequency signal corresponding to the phase difference) and the output of the internal oscillator (a predetermined frequency signal) and outputs it to the first frequency divider. The first frequency divider divides the clock signal and outputs a time count value that is less than a second to the precise time determination unit.

[0077] The second frequency divider generates time information of seconds or more from the time of the second or more in the time error and outputs it to the precise time determination unit. The precise time determination unit determines the precise time including fractions of a second (digits finer than a second) from the time information of seconds or more and the time count value of fractions of a second.

[0078] By means of such a configuration and processing (control), the plurality of reference devices 111-113 and the plurality of measuring devices 211-213, 221-223, 231-233, 241-243 achieve highly accurate time synchronization.

[0079] Furthermore, since a time tag for the ranging timing is generated based on the precise time obtained through this highly accurate time synchronization, it is possible to distinguish with a high degree of accuracy between the time-tagged feature point data of multiple reference devices 111-113 measured at the same time and the time-tagged feature point data of multiple measuring devices 211-213, 221-223, 231-233, and 241-243.

[0080] (Analysis device 81) FIG. 7(A) is a diagram showing an example of a functional block of an analysis device, and FIG. 7(B) is a diagram showing an example of a functional block of a displacement measuring unit.

[0081] As shown in Fig. 7(A), the analysis device 81 includes a communication unit 811, a measurement device position detection unit 812, a position coordinate unification unit 813, a displacement measurement unit 814, and a notification unit 815. As shown in Fig. 7(B), the displacement measurement unit 814 includes a grid point setting unit 8140, a point cloud data adjustment unit 8141, a grid point data generation unit 8142, a grid point data filter processing unit 8143, and a grid point displacement calculation unit 8144. The analysis device 81 is realized by an arithmetic processing device such as a computer.

[0082] The communication unit 811 receives the point cloud data from the reference device 111 via the network 800, and stores it in the memory unit 810. The memory unit 810 stores time-tagged feature point data measured by the multiple reference devices 111-113 and the multiple measuring devices 211-213, 221-223, 231-233, and 241-243.

[0083] The measuring device position detection unit 812 detects feature point data representing the measuring device. Specifically, a reflecting member is disposed in each of the multiple measuring devices 211-213, 221-223, 231-233, 241-243. The reflecting member has a reflection intensity higher than the reflection intensity at the position of the feature point present on the wall surface 900 of the tunnel 90. When the measuring device position detection unit 812 detects this feature point with high reflection intensity, it detects that the feature point is due to reflection from the reflecting member of the measuring device.

[0084] The measuring device position detection unit 812 outputs feature point information indicating feature points of the multiple measuring devices to the position coordinate unification unit 813 .

[0085] The position coordinate unification unit 813 calculates the position coordinates of the multiple measuring instruments 211-213, 221-223, 231-233, and 241-243 in a coordinate system (unified coordinate system) in which the position coordinates of the reference instrument 111 are set as the reference point (origin) based on feature point information indicating the feature points of the multiple measuring instruments.

[0086] Specifically, the position coordinate unification unit 813 calculates the position coordinates of the measuring device 211 in a unified coordinate system with the position coordinates of the reference device 111 as a reference point, from the feature point data of the measuring device 211 detected by each of the multiple reference devices 111-113. Since the position coordinates of the multiple reference devices 111-113 in the unified coordinate system are known, the position coordinates of the measuring device 211 in the unified coordinate system can be calculated by obtaining the feature point data (measurement distance and orientation) of the measuring device 211 from the multiple reference devices 111-113.

[0087] Similarly, the position coordinate unifying unit 813 calculates the position coordinates of the measuring device 212 and the measuring device 213 in the unified coordinate system.

[0088] Furthermore, the position coordinate unifying unit 813 calculates the position coordinates of the multiple measuring instruments 221-223 in the unified coordinate system. Since the position coordinates of the multiple measuring instruments 211-213 in the unified coordinate system have been calculated by the above-mentioned process, the position coordinates of the multiple measuring instruments 221-223 in the unified coordinate system can be calculated.

[0089] Similarly, the position coordinate unifying unit 813 calculates the position coordinates of the plurality of measuring instruments 231-233 and the plurality of measuring instruments 241-244 in the unified coordinate system.

[0090] The position coordinate unifying unit 813 uses the position coordinates of the multiple measuring instruments 211-213, 221-223, 231-233, and 241-243 in the unified coordinate system to convert the position coordinates of the feature points measured by these measuring instruments into position coordinates in the unified coordinate system.

[0091] In addition, the positional relationship between the multiple reference devices 112, 113 and the reference device 111 can be known from the respective positioning results. Therefore, the position coordinate unification unit 813 uses this positional relationship to convert the position coordinates of the feature points measured by the multiple reference devices 112, 113 into position coordinates in the unified coordinate system.

[0092] As a result, the position coordinate unifying unit 813 unifies the position coordinates of all the feature point data into a coordinate system (unified coordinate system) whose reference point is the position coordinate of the reference device 111. Note that, although the case where the position coordinates whose reference point is the position coordinate of the reference device 111 are used has been shown here, the position coordinates of the feature points may be represented in an absolute coordinate system.

[0093] The position coordinate unifying unit 813 outputs the feature point data in which the coordinate systems of the position coordinates of all feature points are unified (point cloud data after coordinate system unification) to a point cloud data filtering processing unit 8121 of the displacement measuring unit 814. Note that the feature point data in which the coordinate system is unified in this manner can also be stored in the storage unit 810.

[0094] The point cloud data adjustment unit 8141 performs a three-dimensional smoothing filter process on the point cloud data (the first feature point data at multiple times of the multiple reference devices 111-113 and the second feature point data at multiple times of the multiple measuring devices 211-213, 221-223, 231-233, 241-243) for each feature point. At this time, the point cloud data adjustment unit 8141 can also perform an interpolation process to increase or decrease the resolution of the feature point data.

[0095] Here, increasing the resolution of the feature point data means increasing the number of feature points set on the wall surface 900 of the tunnel 90 (shortening the interval between adjacent feature points). On the other hand, decreasing the resolution of the feature point data means decreasing the number of feature points set on the wall surface 900 of the tunnel 90 (lengthening the interval between adjacent feature points).

[0096] Furthermore, the point cloud data adjustment unit 8141 eliminates abnormal values ​​in multiple feature point data constituting the point cloud data by the result of the three-dimensional smoothing filter processing. Specifically, the point cloud data adjustment unit 8141 detects feature points whose three-dimensional position coordinate values ​​are significantly different from the surrounding feature point data (for example, feature points that significantly protrude from a surface formed by multiple feature points obtained by smoothing), and eliminates the feature point data of the detected feature points.

[0097] The point cloud data adjustment unit 8141 performs three-dimensional rotation processing and three-dimensional origin offset processing on the point cloud data (a collection of a plurality of feature point data) after the above-mentioned three-dimensional smoothing filter processing.

[0098] This allows the point cloud data adjustment unit 8141 to adjust the point cloud data so that the error (corresponding to the variation that occurs when one feature point is optically measured by multiple devices) of the overlapping portion in the first feature data optically measured by each of the multiple reference devices 111-113 and the second feature data optically measured by each of the multiple measurement devices 211-213, 221-223, 231-233, 241-243 is minimized. The point cloud data adjustment unit 8141 can adjust the first feature data optically measured by each of the multiple reference devices 111-113 and the second feature data optically measured by each of the multiple measurement devices 211-213, 221-223, 231-233, 241-243 so that each point is combined into point cloud data consisting of one value.

[0099] The point cloud data adjustment unit 8141 outputs the adjusted and consolidated point cloud data to the grid point data generation unit 8142.

[0100] The grid point setting unit 8140 sets a plurality of grid points arranged two-dimensionally at equal intervals on the wall surface 900 of the tunnel 90. Fig. 8 is a diagram showing an example of setting the grid points.

[0101] The position coordinates of the plurality of grid points PGX are set using the above-mentioned unified coordinate system in a two-dimensional grid GRD900 whose one axis is the extension direction of the tunnel 90 and the other axis is the circumferential direction of the wall surface 900. The grid point setting unit 8140 outputs the position coordinates of the plurality of grid points PGX to the grid point data generation unit 8142.

[0102] The grid point data generation unit 8142 calculates three-dimensional position coordinates (grid point data) of the plurality of grid points PGX using the position coordinates of each of the plurality of first feature point data Pm21X (X is an integer) and the plurality of second feature point data Pm22X (X is an integer) constituting the point cloud data, and the position coordinates of the plurality of grid points PGX. At this time, the grid point data generation unit 8142 calculates the plurality of grid point data by performing three-dimensional smoothing filter processing and interpolation processing on the plurality of first feature point data and the plurality of second feature point data.

[0103] The grid point data generation unit 8142 performs coordinate conversion processing of planar projection on the curved grid GRD900 as shown in the upper diagram of Fig. 8, thereby converting it into a two-dimensional grid GRD2D (for example, a collection of multiple grid points two-dimensionally projected onto a road 91 of a tunnel 90) as shown in the lower diagram of Fig. 8. Accordingly, the grid point data generation unit 8142 converts the position coordinates of multiple grid points PGX of the curved grid GRD900 into the coordinate system of the two-dimensional grid GRD2D.

[0104] As a result, the coordinates of multiple grid points PGX in a direction perpendicular to the curved surface forming grid GRD900 (corresponding to the distance away from this surface) are converted to coordinates in a direction perpendicular to the plane forming grid GRD2D (corresponding to the distance away from this surface).

[0105] The grid point data generating unit 8142 outputs a plurality of grid point data pieces that have been subjected to such processing to a grid point data filtering unit 8143 .

[0106] The grid point data filter 8143 performs one-dimensional smoothing processing in time series on the coordinates of each grid point in a direction perpendicular to the grid GRD2D of the grid point data generated at multiple times spaced apart on the time axis. The grid point data filter 8143 outputs the multiple grid point data that have been one-dimensionally smoothed to the grid point displacement calculation unit 8144.

[0107] The grid point displacement calculation unit 8144 calculates the vertical change (displacement of each grid point) with respect to the grid GRD2D on the two-dimensional plane for each grid point at multiple times, with an arbitrary time set to zero, and calculates it as time-series data. The grid point displacement calculation unit 8144 outputs the time-series data of the vertical displacement associated with the multiple grid points to the notification unit 815.

[0108] The notification unit 815 uses the three-dimensional displacements of a plurality of grid points to perform notification in at least one of the following ways.

[0109] (A) The notification unit 815 performs three-dimensional smoothing processing on the displacement amounts of multiple grid points at the same time over the entire three-dimensional coordinate system, thereby performing interpolation processing over the entire grid GRD2D. As a result, the smoothed displacement amount has a high resolution relative to the area of ​​the wall surface 900 of the tunnel 90. The notification unit 815 uses the smoothed displacement amounts and the interpolated displacement amounts of multiple grid points to create a heat map of the displacement amounts, the color of which changes depending on the magnitude of these displacement amounts. This allows the user to easily visually check the displacement amounts.

[0110] (B) The notification unit 815 displays a three-dimensional vector (displacement vector) corresponding to the three-dimensional displacement amount for each of the multiple grid points. The three-dimensional vector display is to display an arrow with a length corresponding to the magnitude of the displacement amount for each of the three axes. This allows the user to easily visually check the displacement direction.

[0111] (C) The notification unit 815 prestores a warning threshold for the amount of displacement (magnitude of the displacement vector). The notification unit 815 issues a warning notification when the amount of displacement exceeds the warning threshold. The warning notification may be, for example, displaying a warning image, emitting a warning sound, sending a warning email, turning on or blinking a rotating light, etc. This allows the user to easily grasp that, for example, a dangerous displacement has occurred or that a displacement requiring caution has occurred.

[0112] (Displacement measurement method 1) Fig. 9 is a flowchart showing an example of a system flow of the displacement measuring method according to the first embodiment of the present invention. The specific contents of each process shown in Fig. 9 are specifically explained in the explanation of the configuration above, and detailed explanations will be omitted here except for necessary points.

[0113] The multiple reference devices 111-113 and the multiple measurement devices 211-213, 221-223, 231-233, 241-243 perform time synchronization (S11) and three-dimensional optical ranging (S12) with the horizontal direction (extension direction) of the tunnel 90 as the main axis as separate processes. Specifically, the multiple reference devices 111-113 and the multiple measurement devices 211-213, 221-223, 231-233, 241-243 perform time synchronization at a predetermined time interval. The multiple reference devices 111-113 and the multiple measurement devices 211-213, 221-223, 231-233, 241-243 perform three-dimensional optical ranging at a time interval longer than the time synchronization time interval based on the synchronized time.

[0114] The plurality of reference devices 111-113 and the plurality of measurement devices 211-213, 221-223, 231-233, 241-243 generate feature data (first feature data, second feature data) with a time tag based on the synchronized time from the results of each of the three-dimensional optical ranging (S13).

[0115] The reference device 111 generates point cloud data using the time-tagged feature point data from the other devices (S14). The analysis device 81 generates grid point data based on the point cloud data (S15). The analysis device 81 measures the displacement of the tunnel wall based on the grid point data at multiple times (S16).

[0116] As described above, by using the displacement measurement system and displacement measurement method of the first embodiment, the displacement of a tunnel wall surface can be automatically measured in three-dimensional coordinates with high accuracy.

[0117] In the above configuration, it is preferable that at least the plurality of measuring devices 211-213, 221-223, 231-233, 241-243 includes a temporary storage unit for the point cloud data (point cloud data generated by the measurement data processing unit) transmitted by the measuring device itself. In this case, when each measuring device detects that transmission of the point cloud data from the measuring device itself has failed, the measuring device can retransmit the point cloud data stored in the temporary storage unit.

[0118] This allows the displacement measurement system to suppress loss of point cloud data used for displacement measurement, and allows displacement measurement to be performed more reliably and with higher accuracy.

[0119] [Second embodiment] A displacement measurement system according to a second embodiment of the present invention will be described with reference to the drawings. The displacement measurement system according to the second embodiment differs from the displacement measurement system according to the first embodiment in terms of energy saving of a plurality of measuring devices. Other configurations of the displacement measurement system according to the second embodiment are similar to those of the displacement measurement system according to the first embodiment, and descriptions of similar parts will be omitted.

[0120] Fig. 10 is a functional block diagram of a measuring device according to the second embodiment. Fig. 10 shows a measuring device 211A as an example, but the basic configurations of the other measuring devices are similar, and the measuring device 211A will be described. The measuring device 211A differs from the measuring device 211 according to the first embodiment in that it includes a power supply control unit 2110 and a battery 2117.

[0121] The power supply control unit 2110 supplies power to each functional unit constituting the measuring device 211A using the power stored in the battery 2117. At this time, the power supply control unit 2110 converts the output voltage of the battery 2117 into a voltage (constant DC voltage) appropriate to each functional unit and supplies it.

[0122] The power supply control unit 2110 constantly (continuously) supplies power to the synchronization control unit 2112. As a result, the synchronization control unit 2112 receives a steady supply of power.

[0123] Based on a power supply control signal from the synchronization control unit 2112, the power supply control unit 2110 switches between supplying and stopping power to the distance measurement control unit 2113, the optical distance measurement unit 2114, the feature point data generation unit 2115, the measurement data processing unit 2116, and the communication unit 2119.

[0124] For example, the power supply control unit 2110 includes a first output circuit that steadily outputs a constant voltage, and a second output circuit that can switch between outputting and stopping the constant voltage. An output terminal of the first output circuit is connected to the synchronization control unit 2112. The second output circuit includes an input terminal for a power supply control signal from the synchronization control unit 2112, and an output terminal of the second output circuit is connected to the distance measurement control unit 2113, the optical distance measurement unit 2114, the feature data generation unit 2115, the measurement data processing unit 2116, and the communication unit 2119.

[0125] As described above, the synchronization control unit 2112 operates with constant power supply via the power supply control unit 2110. The synchronization control unit 2112 generates a power supply control signal (power supply permission signal) that permits power supply during a period of synchronization control, a period from the start timing of optical ranging to the optical ranging period, a period of feature point data generation processing, a period of receiving point cloud data (feature point data) from other devices, a period of point cloud data generation processing, and a period of transmitting point cloud data.

[0126] The synchronization control unit 2112 generates a power supply control signal (power supply stop signal) for stopping the power supply during other periods.

[0127] More specifically, when the timing of time synchronization control comes in the time counted within the synchronization control unit 2112, the synchronization control unit 2112 generates a power supply permission signal for the communication unit 2119 and outputs it to the power supply control unit 2110. In addition, when the synchronization control unit 2112 receives a time synchronization end signal from the communication unit 2119, the synchronization control unit 2112 generates a power supply stop signal for the communication unit 2119 and outputs it to the power supply control unit 2110.

[0128] Furthermore, when the timing of optical distance measurement comes in the time counted within the synchronization control unit 2112, the synchronization control unit 2112 generates a power supply permission signal and outputs it to the power supply control unit 2110. Then, for example, when the synchronization control unit 2112 detects that the transmission process of the point cloud data by the measurement data processing unit 2116 has been completed, more specifically, when the synchronization control unit 2112 receives a signal indicating the completion of the transmission process of the point cloud data from the communication unit 2119, the synchronization control unit 2112 generates a power supply stop signal and outputs it to the power supply control unit 2110.

[0129] Upon receiving the power supply permission signal, the power supply control unit 2110 starts supplying power to the distance measurement control unit 2113, the optical distance measurement unit 2114, the feature point data generation unit 2115, the measurement data processing unit 2116, and the communication unit 2119. When the power supply control unit 2110 receives a power supply permission signal for the communication unit 2119 (when the synchronization control unit 2112 performs time synchronization control), it supplies power only to the communication unit 2119.

[0130] When the power supply control unit 2110 receives the power supply stop signal, it stops the power supply to the distance measurement control unit 2113 , the optical distance measurement unit 2114 , the feature point data generation unit 2115 , the measurement data processing unit 2116 , and the communication unit 2119 .

[0131] Such control can be realized not only for the plurality of measuring instruments 211-213, 221-223, 231-233, and 241-243, but also for the reference instrument 112 and the reference instrument 113. Furthermore, it can also be realized for the reference instrument 111.

[0132] In the above configuration, the power of the communication unit 2119 is turned off by default, and turned on during time synchronization, optical ranging, generation of feature point data, and communication of measurement data. However, the communication unit 2119 may be always turned on together with the synchronization control unit 2112. In this case, the synchronization control unit 2112 can omit power supply control for the communication unit 2119 in accordance with time synchronization.

[0133] The above-mentioned power supply control (sleep control) is performed when time synchronization is established among the multiple reference devices 111-113 and the multiple measuring devices 211-213, 221-223, 231-233, 241-243. In other words, when time synchronization is not established immediately after starting up the displacement measuring system, or when synchronization becomes poor (asynchronized state) after time synchronization (for example, when the time difference among the multiple measuring devices becomes a predetermined error or more), the power supply control (sleep control) is not performed.

[0134] Fig. 11 is a timing chart showing an example of processing of the master station reference device, slave station reference device, and measurement device of the displacement measurement system according to the second embodiment. Fig. 11 shows the master station reference device 111, slave station reference device 112, and measurement device 212 as examples, and shows a case where the measurement device 212 transmits point cloud data generated by itself to the reference device 112.

[0135] 11, the reference device 111, the reference device 112, and the measurement device 212 continuously execute the above-mentioned time synchronization at a predetermined time synchronization period (1 second in FIG. 11). This allows the reference device 111, the reference device 112, and the measurement device 212 to continuously execute highly accurate time synchronization.

[0136] In addition, the reference device 111, the reference device 112, and the measurement device 212 perform the above-mentioned optical ranging, generate feature point data, receive point cloud data from other devices, generate point cloud data in their own devices, and transmit the point cloud data generated in their own devices at a predetermined ranging period (Ts seconds in Figure 11).

[0137] When the reference device 111, the reference device 112, and the measurement device 212 finish the above series of processes, they each transition to a sleep mode. The sleep mode is a mode in which the above-mentioned power supply stop signal stops the functions of optical ranging, generation of feature point data, reception of point cloud data from other devices, generation of point cloud data in the own device, and transmission of point cloud data generated in the own device, and stops the power supply to the functional units related to these functions (see the above explanation).

[0138] As shown in Figure 11, the measuring device 212 receives point cloud data from the side farther than the first entrance / exit EW1 of the tunnel 90 than the measuring device itself, combines it with the feature point data generated by the measuring device itself to generate point cloud data for the measuring device, and transmits it to the reference device 112.

[0139] The reference device 112 receives the point cloud data from the measurement device 212 , combines it with the feature point data generated by its own device to generate point cloud data of its own device, and transmits it to the reference device 111 .

[0140] The reference device 111 receives the point cloud data from the reference device 112, combines it with the feature point data generated by its own device to generate point cloud data of its own device (point cloud data to be transmitted to the analysis device 81), and transmits it to the analysis device 81.

[0141] By transferring point cloud data in this way, the amount of data processed by the measuring device 212 becomes smaller than the amount of data processed by the reference device 112. Therefore, the operating time of the measuring device 212 can be shortened. This enables the measuring device 212 to consume less power than the reference device 112 and the reference device 111.

[0142] The measurement device 212 is preferably battery powered since it is disposed inside the tunnel 90. Such power saving can extend the battery life of the measurement device 212, for example reducing the frequency of battery replacement.

[0143] Such a relationship is not limited to the multiple measuring devices 211-213 including the measuring device 212, but also applies to the multiple measuring devices 221-223, the multiple measuring devices 231-233, and the multiple measuring devices 241-243. Therefore, the power consumption of the measuring device 211-213 can be reduced, and the power consumption of the multiple measuring devices 221-223, the multiple measuring devices 231-233, and the multiple measuring devices 241-243 can be reduced, and the battery life of each device can be extended. In particular, the amount of data to be processed becomes smaller as the device approaches the end of the communication, that is, the more measuring devices 221-223 than the measuring device 211-213, the more measuring devices 231-233 than the measuring device 221-223, and the more measuring devices 241-243 than the measuring devices 231-233. As a result, the closer the measuring device is to the end of the communication based on the reference device 111, the shorter the time that power supply is required (the longer the sleep time), and further power saving can be realized for these measuring devices.

[0144] (Displacement measurement method 2) Fig. 12 and Fig. 13 are flowcharts showing an example of a system flow of a displacement measuring method according to the second embodiment of the present invention. Note that the A mark in Fig. 12 and Fig. 13 is a symbol indicating a connection between the flowcharts. The specific contents of each process shown in Fig. 12 and Fig. 13 are specifically explained in the explanation of the configuration above, and detailed explanations will be omitted here except where necessary.

[0145] 12, a plurality of reference devices 111-113 and a plurality of measuring devices 211-213, 221-223, 231-233, 241-243 (hereinafter collectively referred to as each device) detect the timing of time synchronization based on the internal clock of each device. When each device detects the timing of time synchronization (S21: YES), it turns on the power of the communication unit (S22).

[0146] If there is a time synchronization response from the other devices (S23: YES), each device transmits and receives time synchronization information through the communication unit and executes time synchronization control (S24). This puts each device into a time-synchronized state, and measurement by optical distance measurement is enabled. When each device is in a time-synchronized state, it turns off the power supply for the communication unit (S25). After that, each device transitions to optical distance measurement as shown in FIG. 13.

[0147] Each device enters a state of waiting for control for time synchronization control if there is no response for time synchronization from the other devices (S23: NO). Each device continues the state of waiting for control unless the waiting time has timed out (TO) (S31: NO) or the validity period of time synchronization has timed out (TO) (S32: NO).

[0148] Each device detects several waiting timeouts (TO) (S31: YES), and when it detects a timeout (TO) of the valid period of time synchronization (S32: YES), it disables time synchronization and supplies power to the communication unit at all times, disables the measurement mode, interrupts measurement by optical distance measurement, and continues in sleep state (S33).

[0149] Thereafter, if there is a time synchronization response from the other devices (S34: YES), each device executes time synchronization control (S24). If there is no time synchronization response from the other devices (S34: NO) but point cloud data is received from the other devices (S35: YES), each device transmits the received point cloud data to a higher-level device (the entrance side of tunnel 90) (S36). At this time, if there is no point cloud data received from the other devices (S35: NO), each device maintains a state of waiting for a time synchronization response.

[0150] 13, when each device detects the timing for optical ranging (S41: YES), it turns on the power of the ranging function part (S42). As described above, the ranging function part is a part related to optical ranging, generation of feature point data, and reception, generation, and transmission of point cloud data. Each device returns to step S41 if it is not the timing for optical ranging (S41: NO) or the timing for time synchronization (S411: NO), and returns to step S22 if it is the timing for time synchronization (S411: YES).

[0151] Each device performs three-dimensional distance measurement with the horizontal direction (extension direction) of tunnel 90 as the main axis (S43). Each device generates feature point data (first feature point data, second feature point data) with a time tag based on the synchronized time from the results of the respective three-dimensional optical distance measurement.

[0152] Each device turns on the power of the communication unit (S44). If each device receives point cloud data from another device (S45: YES), it generates point cloud data by adding the feature point data measured by the device itself to the received point cloud data. Each device transmits the point cloud data generated by the device itself to the device at the higher communication level (the entrance side of the tunnel 90) (S46).

[0153] Each device sets a waiting time if no point cloud data is received from another device (S45: NO). Each device maintains a state waiting to receive point cloud data unless the waiting time times out (TO) (S48: NO). When each device detects that the waiting time has timed out (TO) (S48: YES), it transmits the received point cloud data to a device at a higher communication level (the entrance side of tunnel 90) (S46). Then, the reference device 111 transmits the point cloud data to the analysis device 81.

[0154] After transmitting the point cloud data in each device, the power supply of each device is turned off except for the synchronization control unit (S47).

[0155] As described above, by using the displacement measurement system and the displacement measurement method of the second embodiment, the displacement of the tunnel wall surface can be automatically measured in three-dimensional coordinates with high accuracy, and power saving can be achieved.

[0156] [Third embodiment] A displacement measurement system according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 14 is a perspective view showing the device configuration of the displacement measurement system according to the third embodiment.

[0157] As shown in Fig. 14, the displacement measurement system according to the third embodiment differs from the displacement measurement system according to the first embodiment in that reference devices are placed on both sides of a tunnel 90 to perform displacement measurement. Explanations of the same points as those in the displacement measurement system of the first embodiment and points that can be easily understood by the explanation of the first embodiment will be omitted. Note that, although the embodiment of Fig. 13 shows a case where the number of measurement device groups placed in the tunnel 90 is three, this number can also be set appropriately, similar to the first embodiment.

[0158] (Device configuration of displacement measurement system) As shown in FIG. 14, the displacement measurement system according to the third embodiment has reference devices 121, 122, and 123 added to the displacement measurement system according to the first embodiment.

[0159] The reference device 121, the reference device 122, and the reference device 123 are disposed near the second entrance EW2 of the tunnel 90. The reference device 121 has a similar configuration to the reference device 111. The reference devices 122 and 123 have a similar configuration to the reference devices 112 and 113.

[0160] The distance measurement ranges of the multiple reference devices 121-123 include the multiple measurement devices 231-233 in the vicinity of the second entrance EW2 of the tunnel 90. The multiple reference devices 121-123 are capable of communicating with at least the multiple measurement devices 231-233.

[0161] The multiple measuring devices 231-233 are also provided with a reflective member with high reflectivity on the second entrance EW2 side of the tunnel 90. This allows the multiple reference devices 121-123 to more reliably detect the multiple measuring devices 231-233.

[0162] The reference device 111 transmits point cloud data based on the position coordinates of the reference device 111 to the analysis device 81A. The reference device 121 transmits point cloud data based on the position coordinates of the reference device 121 to the analysis device 81A.

[0163] The analysis device 81A calculates, for each feature point, a statistically smoothed value of feature point data based on the position coordinates of the reference device 111 and feature point data based on the position coordinates of the reference device 121. By using such a closure calculation, the position coordinates of each feature point are calculated with higher accuracy.

[0164] [Fourth embodiment] A displacement measurement system according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 15 is a perspective view showing the device configuration of the displacement measurement system according to the fourth embodiment.

[0165] 15, the displacement measurement system according to the fourth embodiment differs from the displacement measurement system according to the first embodiment in that it includes an analysis device 81B instead of analysis device 81A. Other configurations of the displacement measurement system according to the fourth embodiment are similar to those of the displacement measurement system according to the first embodiment, and therefore a description of similar parts will be omitted.

[0166] Analysis device 81B is made up of a group of multiple devices, and includes a data server 891, an analysis delivery server 892, and a terminal 893. Data server 891, analysis delivery server 892, and terminal 893 are connected to network 800.

[0167] The data server 891 stores the point cloud data transmitted from the reference device 111. The analysis and distribution server 892 has the functions of the measurement device position detection unit 812, the position coordinate unification unit 813, and the displacement measurement unit 814 shown in Fig. 7(A) described above. The analysis and distribution server 892 acquires the point cloud data stored in the data server 891, and performs the displacement measurement described above.

[0168] The terminal 893 has the function of the notification unit 815 shown in Fig. 7(A) The terminal 893 acquires the result of the displacement measurement by the analysis and delivery server 892, and notifies it by the various methods described above.

[0169] [Example 1 of time tagging] Fig. 16 is a diagram showing an example of a functional block of a master station master in derivative example 1. A master station 111X1 shown in Fig. 17 differs from the master station 111 shown in Fig. 4 in the way in which time tags are added to feature point data. In the following, only the differences between the master station 111X2 and the master station 111 will be described, and descriptions of similar parts will be omitted. Note that, although only the master station master station master station and the measurement device may adopt a similar configuration.

[0170] The master device 111X1 includes an internal clock 191, a PLL 192, a frequency divider 193, and a measurement data processing unit 1116x.

[0171] The internal clock 191 is free-running, generates an internal clock signal of a predetermined frequency, and outputs it to the PLL 192 .

[0172] The PLL 192 generates a distance measurement reference clock signal of a predetermined frequency (for example, 1 MHz, 10 MHz (but not limited to these)) based on the internal clock signal, and outputs the generated signal to the frequency divider 193 .

[0173] The frequency divider 193 generates a count value synchronized with the distance measurement reference clock signal and outputs the count value to the distance measurement control unit 1113 and the measurement data processing unit 1116x.

[0174] The distance measurement control unit 1113 generates a distance measurement timing signal by referring to the count value, and outputs the distance measurement timing signal to the optical distance measurement unit 1114 .

[0175] As described above, the synchronization control unit 1112 performs time synchronization with other devices. The synchronization control unit 1112 provides the measurement data processing unit 1116x with a time tag TIMETAG based on the time-synchronized precise time.

[0176] The measurement data processing unit 1116X associates the time tag TIMETAG input from the synchronization control unit 1112 with the feature point data DATAm111x input to the measurement data processing unit 1116X at approximately the same time.

[0177] With this configuration, the reference device 111X1 can obtain feature point data DATAm111x to which a time tag TIMETAG with practical accuracy has been assigned, although the time accuracy of the time tag TIMETAG is lower than in the configurations of Figures 4 and 16 described above.

[0178] [Example 2 of time tagging] Fig. 17 is a diagram showing an example of a functional block of a master station master device of Derivation Example 2. A master station 111X2 shown in Fig. 17 differs from the master station 111 shown in Fig. 4 in the way in which time tags are added to feature point data. Only the differences between the master station 111X1 and the master station 111 will be described below, and descriptions of similar parts will be omitted. Note that, although only the master station master device will be described here as an example, the slave station master device and the measurement device may also adopt a similar configuration.

[0179] The master device 111X2 includes a distance measurement time latch unit 190, an internal clock 191, a PLL 192, a frequency divider 193, and a measurement data processing unit 1116x.

[0180] The internal clock 191 is free-running, generates an internal clock signal of a predetermined frequency, and outputs it to the PLL 192 .

[0181] The PLL 192 generates a distance measurement reference clock signal of a predetermined frequency (for example, 1 MHz, 10 MHz (but not limited to these)) based on the internal clock signal, and outputs the generated signal to the frequency divider 193 .

[0182] The frequency divider 193 generates a count value in synchronization with the reference clock signal for distance measurement. The frequency divider 193 outputs the count value to the distance measurement control unit 1113.

[0183] The distance measurement control unit 1113 generates a distance measurement timing signal by referring to the count value, and outputs the distance measurement timing signal. The distance measurement timing signal is input to the optical distance measurement unit 1114 and the distance measurement time latch unit 190.

[0184] As described above, the synchronization control unit 1112 performs time synchronization with other devices. The synchronization control unit 1112 provides the synchronized precise time to the distance measurement time latch unit 190.

[0185] The ranging time latch unit 190 latches the precise time obtained from the synchronization control unit 1112 at the timing when the ranging timing signal is input, for example, by using edge detection of a timing pulse forming the ranging timing signal. The ranging time latch unit 190 generates a time tag TIMETAG(L) based on the latched time, and outputs it to the measurement data processing unit 1116x.

[0186] The measurement data processing unit 1116X associates the time tag TIMETAG(L) input from the distance measurement time latch unit 190 with the feature point data DATAm111x obtained by optical distance measurement at the same timing.

[0187] With this configuration, the reference device 111X2 can obtain feature point data DATAm111x to which a more accurate time tag TIMETAG(L) is added than the reference device 111X1.

[0188] <1> a plurality of first reference devices each capable of acquiring position coordinates of its own device with high accuracy, disposed near a first entrance / exit of the tunnel, each performing optical distance measurement within a distance measurement range including the inside of the tunnel to generate a plurality of first feature point data, and capable of communicating with each other; a plurality of first measurement devices that are arranged within the distance measurement ranges of the plurality of first reference devices in the tunnel, perform optical distance measurement with a distance measurement range on an opposite side to the plurality of first reference devices to generate a plurality of second feature point data, and are capable of communicating with at least one of the plurality of first reference devices; Equipped with the plurality of first reference devices includes a master station and at least two slave stations; a first reference device of the master station generating time synchronization information based on the time reference information; the first reference device of the slave station performs time synchronization control based on the time synchronization information or the time reference information obtained by the first reference device of the slave station; the plurality of first measurement devices perform time synchronization control based on the time synchronization information; The plurality of first reference devices Attaching a time of optical ranging based on the time synchronization information to the first feature data; The plurality of first measurement devices are Attaching a time of optical ranging based on the time synchronization information to the second feature data; The first reference device of the master station generating first point cloud data from the first feature data and the second feature data to which the optical distance measurement time is attached; Displacement measurement system.

[0189] <2> <1> A displacement measurement system comprising: an analysis device that measures a displacement of a wall surface inside the tunnel based on the plurality of first feature point data and the plurality of second feature point data; The analysis device includes: A plurality of grid points are set in a two-dimensional array at predetermined intervals corresponding to the wall surface of the tunnel; Calculating three-dimensional coordinates of a plurality of grid points at a plurality of times using the first point cloud data at the same time based on the optical distance measurement time; measuring a displacement of a wall surface of the tunnel based on three-dimensional coordinates of the plurality of grid points at the plurality of times; Displacement measurement system.

[0190] <3> <1> or <2> A displacement measurement system comprising: The first reference device of the master station receives a GNSS positioning signal, performs positioning, and acquires the position coordinates of the first reference device based on the positioning result. Displacement measurement system.

[0191] <4> <3> A displacement measurement system comprising: The first reference device of the master station uses the time information obtained from the GNSS positioning signal and the 1PPS signal as time reference information. Displacement measurement system.

[0192] <5> <2> A displacement measurement system comprising: the analysis device is disposed at a position different from that of the first reference devices and the first measurement devices; the analysis device and the first reference device of the master station each have a communication means for communicating with each other; The first reference device of the master station transmits the first point cloud data to the analysis device; The analysis device measures a displacement of a wall surface of the tunnel using the received first point cloud data. Displacement measurement system.

[0193] <6> <5> A displacement measurement system comprising: The analysis device is composed of a data server that stores the first point cloud data, and a computer device that measures the displacement of the wall surface of the tunnel using the first point cloud data stored in the data server. Displacement measurement system.

[0194] <7> <1> ~ <6> Any one of the displacement measurement systems described above, The plurality of first reference devices and the plurality of first measurement devices, Time synchronization is performed at a fixed time synchronization cycle, performing optical ranging at a plurality of optical ranging timings spaced apart by a time longer than the time synchronization period; Displacement measurement system.

[0195] <8> <1> ~ <7> Any one of the displacement measurement systems described above, The plurality of first measurement devices are an optical distance measuring unit that performs the optical distance measuring; a power supply control unit that controls a power supply of the optical distance measuring unit, The power supply control unit is turning off the power supply of the optical distance measuring unit during a period when the optical distance measuring is not being performed; Displacement measurement system.

[0196] <9> <2> A displacement measurement system comprising: The analysis device includes: generating a displacement vector for the plurality of grid points in a direction perpendicular to a plane on which the plurality of grid points are arranged based on the displacement; converting the displacement vector into a display displacement vector perpendicular to the wall surface of the tunnel and displaying the vector; Displacement measurement system.

[0197] <10> <9> A displacement detection system comprising: The analysis device includes: displaying a heat map in which the color changes according to the magnitude of the displacement of the wall surface of the tunnel based on the display displacement vectors of a plurality of grid points; Displacement measurement system.

[0198] <11> <9> or <10> A displacement measurement system comprising: The analysis device issues a warning when the magnitude of the displacement vector exceeds a warning threshold. Displacement measurement system.

[0199] <12> <1> ~ <11> Any one of the displacement measurement systems described above, the plurality of first measuring devices temporarily store the second feature data, and when it is detected that the second feature data has not been transmitted to any of the plurality of first reference devices, the plurality of first measuring devices retransmit the second feature data. Displacement measurement system.

[0200] <13> <1> ~ <12> Any one of the displacement measurement systems described above, the plurality of measurement devices are provided with a reflective member having a high reflection intensity of distance measuring light on a side on which the plurality of reference devices are disposed; Displacement measurement system.

[0201] <14> <1> ~ <13> Any one of the displacement measurement systems described above, a plurality of second measuring devices that are arranged within the distance measurement ranges of the plurality of first measuring devices in the tunnel, perform optical distance measurement with a distance measurement range on an opposite side to the plurality of first reference devices for the plurality of first measuring devices, generate a plurality of second feature point data, and are capable of communicating with at least one of the plurality of first measuring devices; the second measurement devices transmit the second feature point data together with an optical ranging time based on the time synchronization information; Displacement measurement system.

[0202] <15> <1> ~ <14> Any one of the displacement measurement systems described above, a plurality of second reference devices each capable of acquiring position coordinates of the own device with high accuracy, disposed near a second entrance / exit of the tunnel, each performing optical distance measurement within a distance measurement range including the inside of the tunnel to generate a plurality of first feature point data, and capable of communicating with each other; the plurality of second reference devices include a master station and at least two slave stations, each of which attaches an optical ranging time based on the time synchronization information to the first feature data; the second reference device of the master station generates second point cloud data from the first feature data and the second feature data to which the optical ranging time is attached; Displacement measurement system.

[0203] <16> <15> A displacement measurement system comprising: an analysis device that measures a displacement of a wall surface inside the tunnel based on the plurality of first feature point data and the plurality of second feature point data; the analysis device calculates three-dimensional coordinates of a plurality of grid points at a plurality of times using the first point cloud data and the second point cloud data at the same time based on the optical ranging time; Displacement measurement system. [Explanation of symbols]

[0204] 111, 112, 113, 121, 122, 123, 111X1, 111X2: Reference device 211-213, 221-223, 231-233, 241-243, 211A: Measuring equipment 81, 81A, 81B: Analysis device 800:Network 810: Storage section 811: Communications Department 812: Measuring device position detection unit 813: Position coordinate integration department 814: Displacement measurement unit 815: Notification Department 891: Data Server 892: Analysis distribution server 893: Terminal 90: Tunnel 91: Road 900: Wall 1110, 1120: GNSS antenna 1111, 1121: GNSS receiver 1112, 1122, 2112: Synchronization control section 1113, 1123, 2113: Distance control section 1114, 1124, 2114: Optical ranging section 1115, 1125, 2115: Feature point data generation unit 1116, 1126, 2116, 1116X: Measurement data processing unit 1118: Point cloud data communication section 1119, 1129, 2119: Communications Department 2110: Power supply control unit 2117: Battery 8121: Point cloud data filter processing unit 8140: Grid point setting section 8141: Point cloud data adjustment section 8142: Grid point data generator 8143: Grid point data filter processing unit 8144: Grid point displacement calculation part 190: Distance measurement time latch section 191: Internal clock 192:PLL 193: Frequency divider

Claims

1. a plurality of first reference devices each capable of acquiring position coordinates of its own device with high accuracy, disposed near a first entrance / exit of the tunnel, each performing optical distance measurement within a distance measurement range including the inside of the tunnel to generate a plurality of first feature point data, and capable of communicating with each other; a plurality of first measurement devices that are arranged within the distance measurement ranges of the plurality of first reference devices in the tunnel, perform optical distance measurement with a distance measurement range on an opposite side to the plurality of first reference devices to generate a plurality of second feature point data, and are capable of communicating with at least one of the plurality of first reference devices; Equipped with the plurality of first reference devices include a master station and at least two slave stations; the first reference device of the master station generates time synchronization information based on the time reference information; the first reference device of the slave station performs time synchronization control based on the time synchronization information or the time reference information obtained by the first reference device of the slave station; the plurality of first measurement devices perform time synchronization control based on the time synchronization information; The plurality of first reference devices Attaching a time of optical ranging based on the time synchronization information to the first feature data; The plurality of first measurement devices are Attaching a time of optical ranging based on the time synchronization information to the second feature data; The first reference device of the master station generating first point cloud data from the first feature data and the second feature data to which the optical distance measurement time is attached; Displacement measurement system.

2. The displacement measurement system according to claim 1 , an analysis device that measures a displacement of a wall surface inside the tunnel based on the plurality of first feature point data and the plurality of second feature point data; The analysis device includes: A plurality of grid points are set in a two-dimensional array at a predetermined interval corresponding to the wall surface of the tunnel; calculating three-dimensional coordinates of a plurality of grid points at a plurality of times using the first point cloud data at the same time based on the optical distance measurement time; measuring a displacement of a wall surface of the tunnel based on three-dimensional coordinates of the plurality of grid points at the plurality of times; Displacement measurement system.

3. The displacement measurement system according to claim 1 , The first reference device of the master station receiving a GNSS positioning signal to perform positioning, and acquiring position coordinates of the device itself based on the positioning result; Displacement measurement system.

4. The displacement measurement system according to claim 3, The first reference device of the master station uses the time information obtained from the GNSS positioning signal and the 1PPS signal as time reference information. Displacement measurement system.

5. The displacement measurement system according to claim 2, the analysis device is disposed at a position different from that of the first reference devices and the first measurement devices; the analysis device and the first reference device of the parent station each have a communication means for communicating with each other; The first reference device of the master station transmits the first point cloud data to the analysis device; The analysis device measures a displacement of a wall surface of the tunnel using the received first point cloud data. Displacement measurement system.

6. The displacement measurement system according to claim 5, The analysis device is composed of a data server that stores the first point cloud data, and a computer device that measures a displacement of a wall surface of the tunnel using the first point cloud data stored in the data server. Displacement measurement system.

7. The displacement measurement system according to claim 1 , The plurality of first reference devices and the plurality of first measurement devices, Time synchronization is performed at a fixed time synchronization cycle, performing optical ranging at a plurality of optical ranging timings spaced apart by a time longer than the time synchronization period; Displacement measurement system.

8. The displacement measurement system according to claim 1 , The plurality of first measurement devices are an optical distance measuring unit that performs the optical distance measuring; a power supply control unit that controls a power supply of the optical distance measuring unit, The power supply control unit is turning off the power supply of the optical distance measuring unit during a period when the optical distance measuring is not being performed; Displacement measurement system.

9. The displacement measurement system according to claim 2, The analysis device includes: generating a displacement vector for the plurality of grid points in a direction perpendicular to a plane on which the plurality of grid points are arranged based on the displacement; converting the displacement vector into a display displacement vector perpendicular to the wall surface of the tunnel and displaying the vector; Displacement measurement system.

10. The displacement detection system according to claim 9, The analysis device includes: displaying a heat map in which the color changes according to the magnitude of the displacement of the wall surface of the tunnel based on the display displacement vectors of a plurality of grid points; Displacement measurement system.

11. The displacement measurement system according to claim 9, The analysis device issues a warning when the magnitude of the displacement vector exceeds a warning threshold. Displacement measurement system.

12. The displacement measurement system according to claim 1 , the plurality of first measuring devices temporarily store the second feature data, and when detecting that the second feature data has not been transmitted to any of the plurality of first reference devices, retransmit the second feature data. Displacement measurement system.

13. The displacement measurement system according to claim 1 , the plurality of measurement devices are provided with a reflective member having a high reflection intensity of distance measuring light on a side on which the plurality of reference devices are disposed; Displacement measurement system.

14. The displacement measurement system according to claim 1 , a plurality of second measuring devices that are arranged within the distance measurement ranges of the plurality of first measuring devices in the tunnel, perform optical distance measurement with a distance measurement range on an opposite side to the plurality of first reference devices for the plurality of first measuring devices, generate a plurality of second feature point data, and are capable of communicating with at least one of the plurality of first measuring devices; the second measurement devices transmit the second feature point data together with an optical ranging time based on the time synchronization information; Displacement measurement system.

15. The displacement measurement system according to claim 1 , a plurality of second reference devices each capable of acquiring position coordinates of the own device with high accuracy, disposed near a second entrance / exit of the tunnel, each performing optical distance measurement within a distance measurement range including the inside of the tunnel to generate a plurality of first feature point data, and capable of communicating with each other; the plurality of second reference devices include a master station and at least two slave stations, each of which attaches an optical ranging time based on the time synchronization information to the first feature data; the second reference device of the master station generates second point cloud data from the first feature point data and the second feature point data to which the optical ranging time is attached; Displacement measurement system.

16. The displacement measurement system according to claim 15, an analysis device that measures a displacement of a wall surface inside the tunnel based on the plurality of first feature point data and the plurality of second feature point data; the analysis device calculates three-dimensional coordinates of a plurality of grid points at a plurality of times using the first point cloud data and the second point cloud data at the same time based on the light ranging time; Displacement measurement system.

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