surveillance system

Abstract

To provide a monitoring system that can further reliably avoid contact between an object and a worker while avoiding false warnings to the worker.SOLUTION: A monitoring system 20 monitors a monitoring space 10 to prevent contact between an object 11 and workers 12A and 12B. The monitoring system 20 includes a positioning system 30 and a warning system 40. The positioning system 30 uses UWB radio waves to locate, in the monitoring space 10, the position of a worker tag 33, which is a tag that can communicate with a plurality of anchors 31 and is carried by the workers, with respect to the plurality of anchors 31. The warning system 40 sets a danger area 15 in the monitoring space 10 where the object 11 and the workers 12A and 12B may come into contact with each other, based on the anchors 31, and warns the worker 12B carrying the worker tag 33 when the position of the worker tag 33 located by the positioning system 30 is in the danger area 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a monitoring system that monitors a monitored space so as to avoid contact between an object and a worker. [Background technology]

[0002] At construction sites and the like, it is necessary to ensure the safety of workers. A system such as that disclosed in Patent Document 1 is known as a system for ensuring the safety of such workers. In the system of Patent Document 1, caution areas are set on the construction site. If there is a worker in the caution area who is not in communication with a specific worker involved in the caution area, a warning is issued to that worker. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-135531 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the method described in Patent Document 1, there is a risk that when a worker is concentrating on his or her work, the worker may forget to communicate with a specific worker, and may end up issuing a warning to a worker who does not need to be warned. [Means for solving the problem]

[0005] A monitoring system that solves the above problem is a monitoring system that monitors a monitored space to prevent contact between an object that can move within the monitored space and a worker working in the monitored space, and includes a positioning system that uses UWB radio waves to determine the position of a worker tag carried by the worker, which is a tag that can communicate with a plurality of anchors in the monitored space, relative to the plurality of anchors, and a warning system that sets danger areas in the monitored space where the object and the worker may come into contact, using the anchors as reference points, and warns the worker carrying the worker tag if the position of the worker tag determined by the positioning system is in the danger area. [Effects of the Invention]

[0006] According to the present invention, it is possible to more reliably avoid contact between an object and a worker while avoiding false warnings to the worker. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an embodiment of a monitoring system. [Figure 2] FIG. 1 is a diagram showing a schematic configuration of a monitoring system according to a first embodiment. [Figure 3] FIG. 2 is a diagram showing an example of processing executed by the information processing device in the first embodiment. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a monitoring system according to a second embodiment. [Figure 5] FIG. 10 is a diagram showing an example of processing executed by an information processing device in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Overview of monitoring system) A schematic configuration of an embodiment of a monitoring system will be described with reference to FIG. 1, the monitoring system 20 is a system that monitors a monitored space 10 so as to avoid contact between an object 11 that can move within the monitored space 10 and workers 12A and 12B working in the monitored space 10. The monitored space 10 is a space such as a tunnel or shaft where the reception environment for signals based on a global positioning satellite system (GNSS) is poor.

[0009] The monitoring system 20 is configured to include a positioning system 30 and a warning system 40 . The positioning system 30 includes tags capable of communicating using UWB (Ultra Wide Band) radio waves, multiple anchors 31, and a data collector 32. Of the tags, the tags carried by workers are worker tags 33. The anchors 31 receive UWB radio waves from worker tags 33 located within their reception range. The anchors 31 output signals based on the received UWB radio waves to the data collector 32. The data collector 32 calculates the distance from each anchor 31 to the worker tag 33 based on the signal from each anchor 31. The data collector 32 transmits the calculated distance to the warning system 40 as positioning data.

[0010] The warning system 40 has an information processing device 42 and a terminal 43 that can communicate wirelessly via an access point 41. The access points 41 are installed in various locations in the monitored space 10 so that the entire area of the monitored space 10 is included in the communication range of the information processing device 42 and the terminal 43.

[0011] The information processing device 42 acquires various types of information and performs various processes based on the acquired information, as well as programs and various data stored in memory. The information processing device 42 may be configured as a circuit including one or more dedicated hardware circuits such as an ASIC, one or more processors that operate according to a computer program (software), or a combination thereof. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. Memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0012] The information processing device 42 has a storage unit 45 that stores area conditions that are input in advance. Based on the area conditions stored in the storage unit 45, the information processing device 42 sets a coordinate system in the monitored space 10 with one of the multiple anchors 31 as the origin, and sets a danger area 15 in the coordinate system of the monitored space 10. Based on the positioning data transmitted by the data collector 32, the information processing device 42 calculates the coordinates of the worker tag 33 in the coordinate system of the monitored space 10. Based on the danger area 15 and the coordinates of the worker tag 33, the information processing device 42 issues a warning to the worker 12B who is located in the danger area 15.

[0013] When issuing a warning, the information processing device 42 transmits a warning signal to the terminal 43 carried by the worker 12B via the access point 41. The terminal 43 that receives the warning signal notifies the worker 12B that it is located in the danger area 15 by emitting a warning sound.

[0014] (First embodiment) A first embodiment of the monitoring system 20 will be described with reference to FIGS. As shown in Fig. 2, in the monitoring system 20 of the first embodiment, the interior of a tunnel 50 is the monitored space, and a traveling vehicle 52 traveling on a rail facility 51 laid in the tunnel 50 is the target. The monitoring system 20 monitors the inside of the tunnel 50 to avoid contact between the traveling traveling vehicle 52 and workers 12C, 12D, and 12E. Note that the various tags shown in Fig. 2 indicate those within the reception range of each anchor 31. The traveling direction of the traveling vehicle 52 is referred to as the X direction, the direction perpendicular to the X direction in a top view as the Y direction, and the height direction as the Z direction.

[0015] In the positioning system 30 of this monitoring system 20, a plurality of anchors 31 (four in this embodiment) and a data collector 32 are mounted on a traveling vehicle 52. In the warning system 40 of this monitoring system 20, access points 41 are installed at various locations in a tunnel 50, and an information processing device 42 is mounted on a traveling vehicle 52.

[0016] In this monitoring system 20, safety area tags 56A, 56B, and 56C indicating a safety area 55 in a tunnel 50 are installed as tags capable of communicating with multiple anchors 31. The safety area tags 56A, 56B, and 56C are fixed, for example, to handrails in a worker's walkway installed along the tunnel 50 at a position away from the rail equipment 51. Note that although only three safety area tags 56A, 56B, and 56C are shown in FIG. 2, safety area tags are also installed on the +X direction side of the illustrated range.

[0017] The area conditions input into the information processing device 42 in advance include one anchor 31 that serves as the origin in the coordinate system of the tunnel 50, the coordinates of other anchors 31 relative to that anchor 31, dangerous area conditions, and safe area conditions.

[0018] The danger area condition of the first embodiment specifies that, when viewed from above, the coordinates of a circle centered on the anchor 31, which serves as the origin, and having a radius of danger distance L, that are located on the side of the anchor 31 in the direction of travel of the traveling vehicle 52 are defined as the danger area 15.

[0019] The danger area condition also includes a condition regarding the danger distance L. Specifically, the danger distance L for each traveling speed of the traveling vehicle 52 is specified in the danger area condition so that the danger distance L increases as the traveling speed of the traveling vehicle 52 increases.

[0020] The safety area condition in the first embodiment is a condition under which the worker passage becomes the safety area 55. Specifically, the safety area condition stipulates that the coordinates located on the opposite side of the traveling vehicle 52 in the Y direction, with boundary line 57 connecting safety area tags 56A, 56B, and 56C in that order as the boundary, are set as the safety area 55.

[0021] (Processing performed by information processing device) A series of processes executed by the information processing device 42 in the monitoring system 20 of the first embodiment will be described. Note that this series of processes is executed repeatedly.

[0022] As shown in FIG. 3, when the information processing device 42 receives the positioning data transmitted by the data collector 32 (step S101), it sets the worker passage in the safety area 55 based on the coordinates of the safety area tags 56A, 56B, and 56C and the safety area conditions (step S102).

[0023] Next, the information processing device 42 acquires the traveling direction of the traveling vehicle 52 based on the coordinate changes of each of the safety area tags 56A, 56B, 56C in the X direction (step S103), and calculates the traveling speed of the traveling vehicle 52 (step S104). Then, based on the calculated traveling speed and the danger area conditions, the information processing device 42 sets a danger distance L according to the traveling speed (step S105).

[0024] Next, the information processing device 42 sets a danger area (step S106). Specifically, the information processing device 42 sets, as the danger area 15, an area within the danger distance L set in step S105, with the anchor 31 serving as the origin as a reference, and in the traveling direction of the traveling vehicle 52 acquired in step S103, with respect to the area excluding the safe area 55.

[0025] Then, the information processing device 42 determines whether the worker is in the danger area 15 based on the coordinates of the worker tag 33 based on the positioning data received in step S101 and the danger area 15 set in step S106 (step S107).

[0026] If there is no worker in the danger area 15 (step S107: NO), the information processing device 42 ends the series of processes. On the other hand, if there is a worker in the danger area 15 (step S107: YES), the information processing device 42 transmits a warning signal to the terminal 43 carried by the worker via the access point 41 (step S108). The terminal 43 that receives the warning signal notifies the worker that he is located in the danger area by emitting a warning sound, and then ends the series of processes. For example, as shown in FIG. 3, if there is a worker 12D in the danger area 15, a warning is issued only to the worker 12D who is in the danger area 15. On the other hand, no warning is issued to the worker 12C who is in the safety area 55 and the worker 12E who is outside the danger area 15.

[0027] According to the monitoring system 20 of the first embodiment, the following effects can be obtained. (1-1) The monitoring system 20 is a system that monitors a traveling vehicle 52 that can move through a tunnel 50 to prevent contact between the vehicle 52 and a worker working in the tunnel 50. The monitoring system 20 is a positioning system 30 that uses UWB radio waves and has a plurality of anchors 31 and worker tags 33 that are tags that can communicate with the plurality of anchors 31 and are carried by the workers, and measures the position of the tag relative to the plurality of anchors 31 in the tunnel 50; and a warning system that sets, based on the anchors 31, danger areas 15 in the tunnel 50 where there is a possibility of contact between the traveling vehicle 52 and the worker, and issues a warning to the worker 12D carrying the worker tag 33 when the coordinates of the worker tag 33 measured by the positioning system 30 are in the danger area 15.

[0028] By using UWB radio waves in this way, it is possible to improve the accuracy of setting the danger area 15 and the coordinates of the worker 12, even in spaces where the reception environment for signals based on the Global Navigation Satellite System (GNSS) is poor. This not only prevents false warnings to the worker, but also more reliably avoids contact between the moving vehicle 52, which is the target, and the worker 12D.

[0029] (1-2) The monitoring system 20 has, as tags, safety area tags 56A, 56B, and 56C that indicate a safety area 55 in the tunnel 50. The warning system 40 sets the safety area 55 based on the coordinates of the safety area tags 56A, 56B, and 56C, and sets the danger area 15 in an area other than the safety area 55. This makes it possible to set the safety area 55 according to the installation positions of the safety area tags 56A, 56B, and 56C, and to avoid issuing false warnings to workers in the safety area 55.

[0030] (1-3) In the monitoring system 20, multiple anchors 31 are set on the moving vehicle 52. The warning system 40 also sets the area around the moving vehicle 52 as a danger area 15. As a result, the coordinate system of the tunnel 50 is set with the moving vehicle 52 at its center, so the danger area 15 can be set in accordance with the movement of the moving vehicle 52.

[0031] (1-4) The warning system 40 acquires the traveling direction of the traveling vehicle 52 and sets the danger area 15 according to the acquired traveling direction. This makes it possible to avoid issuing a false warning to a worker on the opposite side of the traveling direction of the traveling vehicle 52.

[0032] (1-5) The warning system 40 acquires the traveling speed of the traveling vehicle 52, and sets a danger area 15 with a larger danger distance L as the acquired traveling speed of the traveling vehicle 52 increases. As a result, the faster the traveling speed, the farther away the worker is to be warned. As a result, the warning can be given to the worker taking into account the braking distance of the traveling vehicle 52.

[0033] (Second embodiment) A second embodiment of the above-mentioned monitoring system 20 will be described with reference to Figures 4 and 5. The monitoring system 20 of the second embodiment has the same main configuration as the monitoring system 20 of the first embodiment. Therefore, in the second embodiment, only the parts that differ from the first embodiment will be described in detail, and the parts that are the same as those in the first embodiment will be denoted by the same reference numerals and will not be described in detail again.

[0034] 4, in the monitoring system 20 of the second embodiment, a vertical shaft 60 leading to a tunnel is the monitored space, and a suspended load 62 that can be moved within the vertical shaft 60 by a crane 61 is the target. The monitoring system 20 monitors the vertical shaft 60 so as to avoid contact between the suspended load 62 and the workers 12F, 12G.

[0035] In the positioning system 30, a plurality of anchors 31 are installed on a side wall 60S of a shaft 60. The plurality of anchors 31 are installed so that the reception range of each anchor 31 covers a wide area within the shaft 60 (for example, the entire area within the shaft 60), while taking into consideration the reception range of each anchor 31. The plurality of anchors 31 include a plurality of first anchors 31A installed near a first depth and a plurality of second anchors 31B installed near a second depth that is deeper than the first depth.

[0036] In the positioning system 30, tags capable of communicating with the first anchor 31A and the second anchor 31B include a load tag 65 attached to a predetermined position of the load 62 (near the hook position of the crane 61). In the positioning system 30, the data collector 32 includes a first data collector 32A that receives signals from a plurality of first anchors 31A and a second data collector 32B that receives signals from a plurality of second anchors 31B. The first data collector 32A transmits the distances to the various tags calculated based on the signals from each of the first anchors 31A to the information processing device 42 as first positioning data. The second data collector 32B transmits the distances to the various tags calculated based on the signals from each of the second anchors 31B to the information processing device 42 as second positioning data.

[0037] In the warning system 40, the access points 41 are installed at various locations such as the side walls 60S of the shaft 60 so that the entire area within the shaft 60 is within the communication range. The warning system 40 has an imaging device 67 that captures an image of the shape of the suspended load 62 as viewed from above. The imaging device 67 is installed, for example, on the crane 61. The imaging device 67 is configured to be able to communicate with the information processing device 42. The imaging device 67 transmits imaging data of the suspended load 62 to the information processing device 42. The suspended load tag 65 is attached to the suspended load 62 so that its relative position with respect to the imaging device 67 is a predetermined position.

[0038] The information processing device 42 is pre-inputted with the area conditions, which include one anchor (for example, one of the first anchors 31A) that serves as the origin in the coordinate system of the monitored space 10, the coordinates of other anchors relative to that anchor, and dangerous area conditions.

[0039] The danger area condition of the second embodiment stipulates that the coordinates located directly below the load 62, based on the coordinates of the load tag 65 and the imaging data from the imaging device 67, and included in the circle inscribed with the load 62 when viewed from above, are defined as the danger area 15.

[0040] (Processing performed by information processing device) A series of processes executed by the information processing device 42 in the monitoring system 20 of the second embodiment will be described. Note that this series of processes is repeatedly executed while the suspended load 62 is being transported using the crane 61.

[0041] 5, the information processing device 42 acquires the shape of the suspended load 62 as viewed from above based on the imaging data from the imaging device 67 (step S201). The information processing device 42 also acquires positioning data (step S202). In step S202, the information processing device 42 receives the first positioning data transmitted by the first data collector 32A and the second positioning data transmitted by the second data collector 32B.

[0042] Next, the information processing device 42 sets the danger area 15 (step S203). Specifically, the information processing device 42 calculates the coordinates of the suspended load tag 65 based on the received first positioning data and second positioning data. The information processing device 42 sets the area directly below the suspended load 62 as the danger area 15 based on the coordinates of the suspended load tag 65, the shape of the suspended load 62 based on the imaging data, and the danger area conditions.

[0043] Then, the information processing device 42 determines whether or not the worker is in the danger area 15 based on the coordinates of the worker tag 33 based on the first positioning data and the second positioning data acquired in step S202 and the coordinates of the danger area 15 set in step S203 (step S204).

[0044] If there is no worker in the danger area 15 (step S204: NO), the information processing device 42 temporarily ends the series of processes. On the other hand, if there is a worker in the danger area 15 (step S204: YES), the information processing device 42 transmits a warning signal to the terminal 43 carried by the worker via the access point 41 (step S205). The terminal 43 that receives the warning signal notifies the worker that he or she is located in a danger area by emitting a warning sound. For example, as shown in FIG. 4, a warning is issued to the worker 12G who is in the danger area 15.

[0045] According to the monitoring system of the second embodiment, in addition to the effect (1-1) described in the first embodiment, the following effect can be obtained. (2-1) The monitoring system 20 monitors contact between a worker and a suspended load 62 that can move within a vertical shaft 60. The monitoring system 20 has a suspended load tag 65 mounted on the suspended load 62 as a tag. A positioning system 30 detects the position of the suspended load tag 65 relative to the anchors 31, which are installed on a side wall 60S of the vertical shaft 60 according to depth, and the warning system 40 sets the area directly below the suspended load tag 65 as a danger area 15. This makes it possible to avoid contact between the suspended load 62 and the worker in the vertical shaft 60, where radio waves such as GPS cannot reach.

[0046] (2-2) The warning system 40 has an imaging device 67 that captures an image of the suspended load 62. The warning system 40 acquires the shape of the suspended load 62 based on the image data captured by the imaging device 67. Based on the acquired shape of the suspended load 62, the warning system 40 can set the area directly below the suspended load 62 as a danger area.

[0047] The first and second embodiments can be modified as follows: The first and second embodiments and the following modifications can be combined and implemented within the scope of technical compatibility.

[0048] In the second embodiment, the warning system 40 acquires the shape of the suspended load 62 based on the image data captured by the image capture device 67. However, the present invention is not limited to this, and the warning system 40 may acquire the shape of the suspended load 62 by manual input to the information processing device 42.

[0049] In the second embodiment, the warning system 40 sets the area directly below the suspended load 62 as the danger area 15 based on the shape of the suspended load 62. However, the warning system 40 may set the danger area 15 as an area directly below a circle, rectangle, or the like of a predetermined size based on the coordinates of the suspended load tag 65.

[0050] In the second embodiment, when the load 62 is moving horizontally, the information processing device 42 may change the danger area 15 according to the traveling direction of the load 62. Specifically, the information processing device 42 acquires the traveling direction of the load 62 based on changes in the coordinates of the load tag 65. The information processing device 42 then sets the danger area 15 so that the side of the acquired traveling direction is larger. The information processing device 42 may also change the danger area 15 according to the traveling speed of the load 62. Specifically, the information processing device 42 acquires the traveling speed of the load 62 based on changes in the coordinates of the load tag 65. The information processing device 42 then sets the danger area 15 so that the side of the traveling direction is larger the higher the acquired traveling speed. The information processing device 42 may also set the danger area 15 to be a long, narrow area extending farther in the traveling direction.

[0051] In the first embodiment, the danger area 15 may be an area of the same size regardless of the traveling speed of the traveling vehicle 52. In the first embodiment, the danger area 15 may be set not only in the direction of travel of the traveling vehicle 52, but also in an area on the opposite side of the traveling direction of the traveling vehicle 52.

[0052] In the first embodiment, the information processing device 42 obtained the traveling direction of the traveling vehicle 52 based on changes in the coordinates of the safety area tags 56A, 56B, and 56C. However, the present invention is not limited to this. The information processing device 42 may obtain an operation signal of an operation lever of the traveling vehicle 52 and obtain the traveling direction based on the obtained operation signal. Alternatively, a traveling direction tag for detecting the traveling direction may be fixedly disposed in the monitored space 10 as the tag, and the traveling direction of the traveling vehicle 52 may be obtained based on changes in the coordinates of the traveling direction tag.

[0053] In the second embodiment, a safety area may be set inside the shaft 60. In the shaft 60, for example, the area directly below the portion surrounded by connecting multiple safety area tags 56A, 56B, and 56C in order can be set as the safety area.

[0054] In the first embodiment, the safety area is not limited to being set based on the coordinates of the safety area tags 56A, 56B, and 56C. For example, the safety area may be set in advance based on BIM (Building Information Modeling) or CIM (Construction Information Modeling), which can virtually reproduce the monitored space 10. In such a configuration, the position of the safety area and the positions of safety area reference tags that are installed in advance at various locations in the tunnel 50 are included in the model. The information processing device 42 identifies the position of the safety area relative to the multiple anchors 31 based on the relative positions of the safety area reference tags and the multiple anchors 31. This also applies to setting the safety area in the second embodiment. [Explanation of symbols]

[0055] 10...monitored space, 11...object, 12...worker, 15...dangerous area, 20...monitoring system, 30...positioning system, 31...anchor, 31A...first anchor, 31B...second anchor, 32...data collector, 32A...first data collector, 32B...second data collector, 33...worker tag, 40...warning system, 41...access point, 42...information processing device, 43...terminal, 45...memory unit, 50...tunnel, 51...rail equipment, 52...moving vehicle, 53...terminal, 55...safety area, 56...safety area tag, 57...boundary line, 60...shaft, 60S...side wall, 61...crane, 62...suspended load, 65...suspended load tag, 67...image capture device.

Claims

1. A monitoring system that monitors a monitored space to prevent contact between a movable object and a worker working in the monitored space, a positioning system that uses UWB radio waves and includes worker tags carried by the workers as tags capable of communicating with a plurality of anchors in the monitored space and safety area tags that indicate a safety area in the monitored space, and that measures the positions of the worker tags and the safety area tags relative to the plurality of anchors; a warning system that sets a safety area in the monitored space based on the position of the safety area tag using the anchor as a reference, and sets a danger area in the monitored space other than the safety area where the object and the worker may come into contact, and warns the worker who is carrying the worker tag when the position of the worker tag measured by the positioning system is in the danger area. Surveillance system.

2. A monitoring system that monitors a monitored space to prevent contact between a movable object and a worker working in the monitored space, a positioning system that uses UWB radio waves to measure the position of a worker tag carried by the worker in the monitored space, the worker tag being a tag capable of communicating with a plurality of anchors, relative to the plurality of anchors; a warning system that sets a danger area in the monitored space where the object and the worker may come into contact with each other using the anchor as a reference, and issues a warning to the worker carrying the worker tag when the position of the worker tag measured by the positioning system is in the danger area; the monitored space is a space within a tunnel, the object is a vehicle traveling through the tunnel, and the plurality of anchors are installed on the vehicle; The warning system acquires a traveling direction and a traveling speed of the traveling vehicle, and sets the periphery of the traveling vehicle as the danger area in accordance with the acquired traveling direction and traveling speed. Surveillance system.

3. A monitoring system that monitors a monitored space to prevent contact between a movable object and a worker working in the monitored space, a positioning system that uses UWB radio waves to measure the position of a worker tag carried by the worker in the monitored space, the worker tag being a tag capable of communicating with a plurality of anchors, relative to the plurality of anchors; a warning system that sets a danger area in the monitored space where the object and the worker may come into contact with each other using the anchor as a reference, and issues a warning to the worker carrying the worker tag when the position of the worker tag measured by the positioning system is in the danger area; The monitoring space is a space within a shaft, The object is a suspended load, The tag includes a suspended load tag mounted on the suspended load, The positioning system is The plurality of anchors are installed according to the depth of the vertical shaft, and the position of the hanging load tag relative to the plurality of anchors is measured; The warning system comprises: The area directly below the hanging load tag is set as the danger area. Surveillance system.

4. The warning system comprises: The shape of the suspended load is acquired, and the area directly below the suspended load is set as the danger area based on the acquired shape. The monitoring system of claim 3 .

5. A monitoring system that monitors a monitored space to prevent contact between a movable object and a worker working in the monitored space, a positioning system that uses UWB radio waves to measure the position of a worker tag carried by the worker in the monitored space, the worker tag being a tag capable of communicating with a plurality of anchors, relative to the plurality of anchors; a warning system that sets a danger area in the monitored space where the object and the worker may come into contact with each other using the anchor as a reference, and issues a warning to the worker carrying the worker tag when the position of the worker tag measured by the positioning system is in the danger area; the object is a traveling vehicle, and the plurality of anchors are installed on the traveling vehicle; The tag includes a safety area tag indicating a safety area in the monitored space, the positioning system determines a position of the safe area tag relative to the plurality of anchors; The warning system acquires the traveling direction of the traveling vehicle based on a change in the position of the safety area tag, and sets the danger area according to the acquired traveling direction. Surveillance system.

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