JP2019138785A - Site management system - Google Patents

Abstract

To provide a site management system that can rapidly and accurately grasp the positions of workers or machines in a construction site by a method for communication appropriate to the construction site and also takes care of the health and safety of workers.SOLUTION: A site management system 1 according to the present invention has a plurality of receiver antennas 3a to 3d in a room to receive electric waves from wireless tags 2a and 2b, analyzes the electric waves from the wireless tags 2a and 2b received by the receiver antennas 3a to 3d, and detects the positions of the wireless tags 2a and 2b on the basis of a reference azimuth by the AoA (arrival angle method) of electric waves.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an on-site management system, and more particularly to an on-site management system that performs on-site management such as location management and health management of on-site workers in construction sites and distribution warehouses, and on-site management of on-site materials and equipment. Here, the “construction site” refers to the entire construction performed by site workers, and includes construction work sites, civil engineering work sites, plant construction sites, and the like. “Site management” is a general term for labor management, safety management, health management, cost management, process management, and quality management of field workers at a construction site. Further, the “field worker” includes a site manager of a main contractor or a general contractor (abbreviation of general contractor), and a field worker of a subcontractor or a subcontractor (abbreviation of a subcontractor).

  In construction sites, it is important to quickly manage the location of site workers in the construction site. In particular, on-site workers at subcontractors or subcontracts often change the job types of site construction such as dredge, carpenter, plasterer, rebar construction, concrete placement, etc., depending on the construction process plan and progress. In addition, even in the same occupation, field workers from different companies may work together on the construction site. Accordingly, the site manager of the main contractor or general contractor is required to efficiently advance the construction site by the subcontractor or the subcontractor to secure the work period while ensuring safety, and to suppress the increase in construction cost due to construction waste.

  In particular, not only the main contractor or general contractor site manager, but also the location of the subcontractor field workers who entered the construction site can be accurately managed in real time, so that the actual situation of the site work can be grasped in real time. For example, it is possible to avoid accidents by issuing warnings and warnings about places where there is a risk of falling or falling, and thorough safety management can be achieved. In particular, it is possible to quickly deal with an outbreak that cannot be delayed, such as heat stroke and cerebral infarction, by wearing an acceleration sensor that reacts when it falls.

  Similarly, at the construction site, for example, the location of construction materials such as cranes, bulldozers, backhoes, aerial work vehicles, and construction materials such as wall materials and roofing materials used by various types of occupations is always managed. It is important to keep For example, an aerial work platform may be left in a place that has not been designated by a specific subcontractor or sub-contractor after use. The useless work of searching around has become a daily routine.

  In order to perform position management of site workers or site materials and equipment at a construction site, a position management system that responds to various problems at the construction site has been proposed as shown below.

  Patent Document 1 discloses a position recognition device and a position recognition system for recognizing the position of a radio wave transmitter such as an RFID tag. Here, for example, an article with an identification tag is stored in a storage shelf in a storage area, a transmission antenna and a plurality of reception antennas that transmit and receive radio waves to and from the identification tag, and radio waves from the identification tag. Is described to recognize the position of the identification tag with respect to the position recognition device.

  Patent Document 2 discloses a position detection system that detects the position of a moving body. Here, a mobile node comprising a means for receiving a packet including transmission time information, a means for transmitting a packet having the same content as the received packet after a certain elapsed time since the packet was received, and transmission time information Based on the means for transmitting the packet, the means for receiving the packet transmitted by the mobile node, the transmission time information included in the received packet, the time information when the packet was received, and the fixed elapsed time information, A first fixed node comprising means for obtaining a distance between the first fixed node, a means for intercepting a packet transmitted by the first fixed node, a means for intercepting a packet transmitted by a mobile node, and a reception time difference between the two intercepted packets A plurality of second fixed nodes comprising a means for calculating a distance from the mobile node, a first fixed node, and a plurality of second fixed nodes. It is described and means for calculating the location of the mobile node based on the distance information between each mobile node de.

  Patent Document 3 discloses a building position information management system that acquires and manages position information of a person in a building. Here, the building where the floor, the room are electromagnetically zoned by the electromagnetic shielding section using the conductive material on the ceiling, floor, and wall, and the base station antenna of the PHS for offices arranged in the electromagnetic wave zoning area in the building, And a location information management device that acquires and manages location information of a handset terminal of a business PHS by a base station antenna.

  Patent Document 4 discloses a system and a method for specifying a position of a moving object at a construction site. Here, a plurality of IC tags storing unique tag IDs are arranged at fixed positions on the construction site, and the IC tags are also attached to the moving body. The reader device reads the tag ID from the moving tag, reads the tag ID from the fixed tag, and transmits the read tag ID to the management device. The management device receives the tag ID from the reader device, reads out the position information corresponding to the tag ID that is a fixed tag among the received tag IDs from the fixed tag information database, and at the construction site based on the read position information It describes that an area where a moving tag can be located is specified.

JP 2010-91432 A JP 2010-32320 A JP 2003-250175 A JP 2007-271347 A

  FIG. 7 shows an embodiment of a site management system at a construction site using a conventional Beacon (registered trademark). In the room 4, a radio wave transmitter 22 and a receiving antenna 3 that is a fixed node for receiving radio waves transmitted from the radio wave transmitter 22 are provided. Here, the module (Lo) of the chamber 4 has a pitch of 10 m. Conventional location management systems at construction sites used Beacon (2.4 GHz) band radio communications for radio communications, but there are a number of problems due to the recent increase in size and complexity of construction work. Has occurred. First, since conventional wireless communication has a short effective distance, there is a problem that antennas provided indoors must be provided at a pitch of 10 to 20 m. In addition, the conventional wireless communication has a problem that an antenna must be provided for each room because the wireless communication does not pass through the wall material when the room is partitioned by a wall material because the wireless communication is weak. Further, at the construction site, the construction progresses with the passage of time, such as first building the frame of the frame and attaching the floor slab, the outer wall panel, and the inner wall panel. That is, there is a problem that the construction situation changes day by day, and the position of the indoor reception antenna must be changed accordingly.

  The purpose of the present application is to solve such problems and to quickly and accurately grasp the position of field workers and on-site materials and equipment by means of a communication method adapted to the construction site. It is to provide an on-site management system.

  In order to achieve the above object, the field management system according to the present invention has a plurality of reception antennas for receiving radio waves transmitted from radio tags attached to field workers and field materials, and the reception antennas receive the signals. The radio tag is analyzed, and the position of the radio tag is detected based on the reference azimuth based on the arrival angle of the radio wave.

  With the above configuration, the radio waves transmitted from the wireless tags attached to the field workers and the site materials and equipment are received by a plurality of receiving antennas installed in the room, and the received angles of the received radio waves are received by the plurality of receiving antennas. By analyzing (AoA), the indoor position of the wireless tag can be easily grasped.

  This makes it possible to quickly and easily detect and manage the positions of site workers and site materials and equipment at the construction site. Here, the field worker includes a field worker of a main contractor or a general contractor and a field worker of a partner company or a subcontractor. On-site materials and equipment include construction equipment such as crane trucks, backhoes, aerial work platforms, and construction materials such as wall panels and roofing materials.

  Moreover, the field management system is preferably a radio wave transmitter that uses a sub-gigahertz band radio wave that can be transmitted through at least one of a wall material, a ceiling material, and a floor material. As a result, the wireless reach is significantly longer than that of a conventional position management system using the Beacon (registered trademark) (2.4 GHz) band, and the number of indoor receiving antennas can be reduced. Further, even if there is a wall surface in the room, the position information of the wireless tag ahead of it can be acquired. Furthermore, even if the building is under construction and the room conditions change daily, there is no need to replace the antenna. That is, the position information of the indoor wireless tag can be continuously acquired without being influenced by the construction of the building.

  In addition, it is preferable that the wireless tag attached to the site worker is a wristwatch type that operates with a battery such as a dry battery, and the site worker is preferably wound around his / her arm and works at the construction site. As a result, the field management system has a maximum radio wave reach of about 50 m due to the characteristics of radio waves in the sub-gigahertz band, and can significantly reduce the number of receiving antennas installed compared to conventional position detection systems. Even if there is a wall material in the room, the position information of the wireless tag ahead of it can be acquired. In addition, even if the building is under construction and the situation of the room changes every day, there is no need to replace the antenna, and the location information of the indoor wireless tag continues without being affected by the construction of the building. You can get it.

  Moreover, it is preferable that the field management system is a portable type in which a wireless tag attached to a field material is operated by a battery. As a result, the positions of the on-site materials and equipment can be detected, and it is not necessary for the on-site workers to run around the site to search for unnecessary work.

  In addition, the field management system has a wristwatch-type wireless tag attached to a field worker, and a reception node is a fixed node installed in the corner of the room. The fixed node is a right-hand circularly polarized antenna and a left-hand circularly polarized wave. It is preferable that the antenna is composed of a substrate in which a circularly polarized antenna combined with an antenna is incorporated, and receives radio waves from a wireless tag. As a result, the radio transmitted from the wristwatch-type wireless tag attached to the arm by the field worker can be received by either the right-hand circularly polarized antenna or the left-hand circularly polarized antenna, and the wireless system can be made redundant. .

  Moreover, it is preferable that a vital sensor is incorporated in the wireless tag attached to the field worker, and the health care of the field worker can be performed by this vital sensor to detect an abnormal situation during the work. Thereby, for example, blood pressure, heart rate, etc. of the field worker can be detected in accordance with the entry / exit of the field worker to / from the construction site, and the health management of the field worker can be performed at the same time. Furthermore, when an on-site worker has an abnormality in the blood pressure, heart rate, or the like at the construction site, the abnormality can be detected at an early stage by a vital sensor.

  Furthermore, it is preferable that an acceleration sensor is mounted on the wireless tag attached to the field worker and the field equipment. As a result, when an acceleration sensor is attached to the wireless tag attached to the field worker, an accident value such as the field worker dropping into the opening occurs, an abnormal value is displayed on the acceleration sensor. It can respond quickly by early detection. In addition, when an on-site worker falls due to heat stroke or cerebral infarction, an abnormal value is displayed on the acceleration sensor, so that it can be quickly handled by early detection. Furthermore, since the acceleration sensor is attached to the wireless tag attached to the on-site equipment, it is possible to prevent accidents where the on-site equipment comes into contact with other equipment or an accident that collides with other equipment. And quickly understand that an accident has occurred.

  As described above, according to the on-site management system according to the present invention, the position of on-site workers and on-site materials and equipment can be grasped quickly and accurately by the communication method adapted to the construction site, and the health management and safety of the on-site workers are ensured. It is possible to provide an on-site management system that performs management and the like simultaneously.

It is explanatory drawing which shows schematic structure of one Embodiment of the site management system which concerns on this invention. It is explanatory drawing which shows the comparison of the radio | wireless system which can be utilized with a position management system etc. It is explanatory drawing which shows the outline | summary of the position estimation system of the indoor wireless tag by a fixed node. It is explanatory drawing which showed the reach | attainment range of the radio | wireless tag of the radio | wireless tag at the time of using a sub gigahertz band electromagnetic wave in construction sites, such as a building, based on a demonstration experiment result. It is a perspective view which shows the shape and specification of an antenna of a fixed node. It is a top view which shows one Example of the radio | wireless tag for field materials and equipment and a vital sensor. It is explanatory drawing which shows the Example of the site management system in the construction site using the conventional Beacon (trademark).

(Configuration of site management system)
Hereinafter, the field management system 1 according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of one embodiment of the site management system 1. The module (L) of the chamber 4 shown in FIG. 1 has a pitch of about 50 m. FIG. 2 is an explanatory diagram showing a comparison of wireless systems that can be used in a location management system or the like. Here, the room 4 in the construction site 7 is not limited to each room 4 in the building under construction, and includes, for example, a construction equipment place, a construction material place, a temporary construction facility, and the like.

(Outline of site management system)
As shown in FIG. 1, a fixed node 3 for receiving a radio wave 8 transmitted from the radio tags 2a and 2b is provided in the room 4 in the construction site 7. Here, the wireless tags 2 a and 2 b are radio wave transmitters, and the wireless tag 2 a is attached to the wristwatch of the field worker 5. The wireless tag 2 b is attached to a lifter that is the on-site equipment 6 brought into the room 4. Fixed nodes 3a, 3b, 3c, 3d provided at the four corners of the chamber 4 are receiving antennas, receive radio waves from the radio tags 2a, 2b, transmit their angle data to the position totaling server 10, and receive the position totaling server. 10 estimates the reception angles of the fixed nodes 3a, 3b, 3c, and 3d to estimate the positions of the wireless tags 2a and 2b. Note that the installation locations of the fixed nodes 3 a, 3 b, 3 c, 3 d are not limited to the four corners of the room 4, and may be arbitrary installation locations. Further, the number of the fixed nodes 3a, 3b, 3c, and 3d is not limited to four, and may be other numbers. Due to the module pitch (L) of the chamber 4, the fixed nodes 3a, 3b, 3c and 3d can be provided with a significantly smaller number and a larger pitch than before.

(Wireless system used in this system)
The wireless system of the wireless tags 2a and 2b used in this system will be described with reference to FIG. Typical wireless systems that are generally used include ultrasound, Picalico (registered trademark), EnoOcean (registered trademark), sub-GHz (sub-gigahertz) wireless communication, Beacon (registered trademark), RFID, and the like. Among these, the ultrasonic wave is an elastic vibration wave having a frequency exceeding 2 kHz per second, and is mainly used for nondestructive inspection in the construction field. However, it is weak against a shield and has an effective distance of 7 m at maximum, which is not suitable for the wireless communication of the present invention. Picalico (registered trademark) is a communication method for transmitting a signal by a change in color. Although the effective distance is a maximum of 45 m, it is not suitable for communication of this system because it is weak against a shield. EnoOcean (registered trademark) is characterized by ultra-low power consumption because it is a battery-less wireless transmission technology, but it has an effective distance of up to 30m indoors and requires many wireless repeaters. Not suitable for wireless communication. Beacon (registered trademark) has an effective distance of up to 30 m indoors, requires a large number of wireless repeaters, and is not suitable for wireless communication of this system. RFID is a system for reading and writing RF tag data in a non-contact manner using radio waves. Since the effective distance is a maximum of 6 m, it is mainly used for an entrance / exit management system by a gate device.

(Sub-GHz wireless communication)
The sub-GHz radio refers to radio communication using a frequency band less than 1 GHz. Here, “sub” means “less than”. Conventionally, in Japan, the 315 MHz band, 400 MHz band, and 950 MHz band have been used for wireless communication, but since July 2012, the 920 MHz band has become available by international cooperation instead of the 950 MHz band. As shown in FIG. 2, the characteristics of the sub-GHz radio using the 920 MHz band are strong against a shield inside the building and have a long effective distance of up to 1000 m, which is suitable for wide-area wireless communication. In addition, power consumption is about one year, and a long life can be achieved by devising the battery. Therefore, compared with other wireless systems, it can be said that the wireless system is most suitable at the construction site as shown below.

(Indoor location management system)
FIG. 3 shows an outline of a position estimation system for the wireless tags 2a and 2b in the room 4 by the fixed nodes 3a, 3b, 3c and 3d. 3 (a), 3 (b), and 3 (c), when the wireless tag 2a is located at different positions in the chamber 4, the positions are analyzed from the fixed nodes 3a, 3b, 3c, and 3d. The For example, when in the left central portion in the drawing as in FIG. 3 (a), taken as the range of the angle alpha ₁ from the fixed node 3a, seen as a range of the angle alpha ₂ from the fixed node 3b , from the fixed node 3c seen as a range of the angle alpha _3, and, from the fixed node 3d taken as the range of the angle alpha _4. From overlapping portions of these angles _{alpha. 1 to} alpha ₄ becomes possible wireless tag 2a to identify the existence range. Wireless tag 2a is taken as the range of the angle _{alpha. 1 to} alpha ₄ is also fixed node 3a~3d when in right side lower in the chamber 4 as shown in FIG. 3 (b). Further, the wireless tag 2a is taken as the range of the angle _{alpha. 1 to} alpha ₄ is also fixed node 3a~3d when there to the central portion toward the chamber 4 as shown in FIG. 3 (c). In addition, the x mark in a figure shows the point which the line | wire of the both ends which show the range of an angle crosses. Then, the position totaling server 10 connected to the fixed nodes 3a, 3b, 3c, 3d analyzes the radio waves received from the wireless tags 2a, 2b, and uses the reference azimuth as a reference for the radio wave arrival angle (AoA) system Detect position.

  Note that the fixed nodes 3a to 3d can estimate the positions of the wireless tags 2a and 2b by at least two, but in order to improve the accuracy of the position, the angles are usually detected by all four. Further, although the accuracy of position estimation increases as the number of fixed nodes 3 increases, it is sufficient to know which side of which room 4 the positions of the on-site worker 5 and the on-site materials and equipment 6 are. Unless it is an irregular shape, it is standard to install one at each corner.

  FIG. 4 shows the reach of radio tags 2a and 2b when sub-gigahertz band radio waves 8 are used at a construction site 7 such as a building. In FIG. 4, when the field worker 5 or the field equipment 6 exists on the first floor of the building, the number of floors of the sub-gigahertz band radio wave 8 reaches the floor of the building based on the result of the demonstration experiment. As a result, the following knowledge was obtained. (1) The radio wave 8 in the sub-gigahertz band is transmitted through all five ceiling materials 17 and floor materials 14. (2) It was found that the radio wave 8 in the sub-gigahertz band also penetrates the ceiling material 17 and the floor material 14 having a thickness of 1 m or more, and the radio wave intensity when five pieces are transmitted is attenuated by 75%. (3) It was found that all of the three types of power consumption bands, weak, medium and strong, pass through obstacles. As a result of this demonstration experiment, it was found that in an environment with five obstacles having a thickness of 1 m, radio waves reach the building height (H) of 20 m. Accordingly, it is estimated that radio waves reach farther in an environment where the obstacle is thinner than 1 m and less than five.

(Wireless tag and fixed node)
FIG. 5 is a perspective view showing a schematic shape and specifications of the fixed node 3 that is a receiving antenna. FIG. 5A is a perspective view showing a radio wave reception method of the fixed node 3. FIG. 5B is a perspective view showing the overall shape of the fixed node 3. As shown in FIG. 5A, the fixed node 3 is configured by a board on which a radio wave receiving node and a plurality of circularly polarized antennas 13 are incorporated, and receives radio waves from the radio tags 2a and 2b.

  As shown in FIG. 5A, the fixed node 3 includes three circularly polarized antennas 13a and 13b, which are a combination of a right-handed circularly polarized antenna 13a and a left-handed circularly polarized antenna 13b. It is attached. This is because the radio tags 2a and 2b from which radio waves are transmitted are wristwatch-type, and the incident angle of the radio waves changes instead of a constant angle. And the left-handed circularly polarized antenna 13b are combined to expand the reception range, and any one of the circularly polarized antennas 13a and 13b receives. That is, when a failure occurs in reception of either the right-hand circularly polarized antenna 13a or the left-hand circularly polarized antenna 13b, the reception can be backed up by the other antenna. In addition, with the conventional ordinary antenna, the intensity of the received radio wave varies depending on the angle of the wireless tag, and accurate and stable position detection cannot be performed. This system makes it possible to stably receive radio waves from the wireless tags 2a and 2b. So-called system redundancy is achieved.

  The wireless tag 2a attached to the field worker 5 is a wristwatch-type wireless tag 2a for field workers. The wireless tag 2b for on-site materials and equipment attached to the on-site materials and equipment 6 is obtained by attaching the wireless tag 2a to a wristwatch band, and is battery-powered so that it can be used without being charged for 2 years. The reason why the wireless tag 2a is attached to the wristwatch band is that it can be prevented from being lost by being integrated with the wristwatch, and that the wristwatch is often exposed and the radio wave easily reaches. The location information of the site worker 5 is output to the management center or the like that performs location management by the site worker wireless tag 2a. And the vital sensor 11 and the acceleration sensor 12 which are mentioned later are attached. The wireless tag 2b for on-site equipment is of a pendant type and has a shape that can be easily attached to the on-site equipment 6. The location information of the on-site equipment 6 is output to a management center or the like that performs location management by the on-site equipment radio tag 2b. It is possible to search for on-site materials and equipment 6 whose location is not known due to theft at the site, and to track the on-site materials and equipment 6 when valuables or the like are stolen within the construction site 7.

(Vital sensor)
FIG. 6 shows one embodiment of a wristwatch-type radio tag 2a for field workers and a radio tag 2b for field equipment. 6A shows a wristwatch-type wireless tag 2a for field workers, and FIG. 6B shows a wireless tag 2b for equipment. A radio wave transmitter 20 is provided in the wristwatch-type radio tag 2a for field workers and the radio tag 2b for field equipment. Further, both the field worker wireless tag 2a and the field material wireless tag 2b operate without being charged by the battery 21 for two years. Further, a vital sensor 11 is incorporated in the field worker wireless tag 2a. During this time, the vital sensor 11 can simultaneously manage the health of the field worker 5. This vital sensor 11 outputs not only the position information but also information such as pulse and body temperature.

(Acceleration sensor)
An acceleration sensor 12 is mounted on each of the wireless tags 2 a and 2 b attached to the field worker 5 and the field material 6. The acceleration sensor 12 attached to the wireless tag 2a of the field worker 5 displays an abnormal value on the acceleration sensor 12 when an accident such as the field worker 5 dropping into the opening of the construction site 7 occurs. An alarm is notified. As a result, early detection can be made and accidents can be dealt with quickly. Further, even when the field worker 5 falls down due to heat stroke or cerebral infarction, an abnormal value is displayed on the acceleration sensor 12, so that it can be quickly dealt with by early detection. Furthermore, the wireless tag 2b with the acceleration sensor 12 attached to the on-site equipment 6 can prevent an accident that the on-site equipment 6 comes into contact with or collides with other equipment. In addition, the on-site equipment 6 can be traced by the wireless tag 2b attached to the on-site equipment 6 when the site is stolen.

  Based on the position information received from the fixed node 3, the position totaling server 10 of the site management system 1 displays the position of the field worker 5 on the map of the construction site 7, for example, a circle or triangle symbol and an individual name, Displayed with the name of the organization. If there is no movement within a certain time, the symbol is displayed in red, for example. Similarly, based on the position information received from the fixed node 3, the position totaling server 10 displays the position of the site equipment 6 on the map of the construction site 7, for example, a circle or triangle symbol, the name of the material or equipment, and the like. Display together. If there is no movement within a certain time, the symbol is displayed in red, for example. Furthermore, when the radio wave transmitter 22 provided in the construction site 7 is replaced, the on-site worker 5 in charge can easily change the system using a portable terminal, and the system is not activated. Both can collect location information automatically.

  The configuration, shape, size, and arrangement relationship of the on-site management system 1 described in the above embodiments are merely schematically shown to the extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the described embodiments, and can be variously modified without departing from the scope of the technical idea shown in the claims.

1 field management system, 2 wireless tag (or radio wave transmitter), 2a field worker wireless tag, 2b field material wireless tag, 3 fixed node or receiving antenna, 3a, 3b, 3c, 3d Fixed node, 4 rooms, 5 field workers, 6 field equipment, 7 construction site, 8 radio waves (in sub-gigahertz band), 10 position counting server, 11 vital sensor, 12 acceleration sensor, 13 circularly polarized antenna , 13a Right-handed circularly polarized antenna, 13b Left-handed circularly polarized antenna, 14 Floor material, 17 Ceiling material, 18 Antenna support stand, 20 Radio transmitter, 21 Battery, 22 Radio wave transmitter, Lo Module pitch of the room in the prior art , L The module pitch of the chamber in the present invention, H The height of the building.

Claims (7)

  A plurality of receiving antennas for receiving radio waves transmitted from radio tags attached to field workers and on-site materials and equipment are installed in a room, the radio waves received by the reception antennas from the radio tags are analyzed, and the radio tags Is detected on the basis of a reference azimuth with respect to the arrival angle of the radio wave.   2. The field management system according to claim 1, wherein the wireless tag is a radio wave transmitter that uses a sub-gigahertz band radio wave that can pass through at least one of a wall material, a ceiling material, and a floor material. A featured site management system.   3. The field management system according to claim 2, wherein the wireless tag attached to the field worker is a wristwatch type that operates with a battery, and the field worker is wound around his / her arm and works at a construction site. On-site management system characterized by   The field management system according to claim 2, wherein the wireless tag attached to the field material is a battery-operated portable type.   The field management system according to claim 1, wherein the wireless tag attached to the field worker is a wristwatch type, and the reception antenna is a fixed node installed at a corner of a room. The fixed node is configured by a substrate in which a circularly polarized antenna in which a right-handed circularly polarized antenna and a left-handed circularly polarized antenna are combined is incorporated, and receives the radio wave from the wireless tag. A featured site management system.   The field management system according to any one of claims 2 to 5, wherein a vital sensor is incorporated in the wireless tag attached to the field worker, and the health care of the field worker is performed by the vital sensor. A field management system characterized by detecting abnormal situations during work. The field management system according to claim 2, wherein an acceleration sensor is mounted on the wireless tag attached to the field worker and the field material. Site management system.

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