Indoor Positioning System

Abstract

To provide a location detection system that can prevent wrong detection of a location of equipment disposed in a broad indoor area.SOLUTION: A location detection system detects which any area of a plurality of areas object equipment put in an object site is disposed in. The location detection system has: a slave machine that is installed in the object equipment; a plurality of relay machines that is installed in each of a plurality of areas; and a master machine that is installed in the object site. The slave machine, relay machines and master machine are configured to transmit transmission information from the slave machine to the master machine by way of multi-hop communication, Herein, transmission output of the slave machine is smaller than that of the relay machine. The master machine is configured to transmit the received transmission information to a management server. The management server is configured to output a detection result of which any area of the plurality of areas the object equipment is disposed in on the basis of the transmission information. For example, the transmission output of the relay machine stands 15 mW to 20 mW, and the transmission output of the slave machine is equal to or less than 1 mW.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an indoor position detection system, and more particularly to an indoor position detection system for detecting the position of equipment and materials arranged in a wide range of indoor areas. [Background technology]

[0002] Various methods have been proposed as technology for detecting the location of an object when searching for a specific object within a certain space. For example, there are methods that use a private network based on the Global Positioning System (GPS) or a Radio Frequency Identification (RFID) tag system. Of these, GPS is almost exclusively used for detecting positions outdoors where radio waves from satellites can reach. For multi-story buildings made of reinforced concrete or steel-reinforced concrete, even if they are under construction, radio waves from outside have a hard time penetrating the iron and concrete that make up the building, so that indoors, especially in spaces surrounded by iron and concrete, radio waves have a hard time reaching them.

[0003] Patent Document 1 discloses a technology related to an indoor position detection system. In this technology, a first signal from a first transmitter that moves with an object to be detected and a second signal from the positions of a plurality of second transmitters whose positions have been confirmed in advance are received by a receiver using a radio frequency identification (RFID) tag system, a personal handy-phone system (PHS), a global positioning system (GPS), and the like. The system then compares the electric field strength of each transmitter received by the receiver, and determines that the position of the second transmitter having a value close to the electric field strength of the first transmitter is the position close to the object, and detects the position of the object. This makes it possible to reduce the number of receivers that need to be connected via a transmission line compared to conventional systems using radio frequency identification (RFID) tags. However, a large number of transmitters are required, and even if the number is reduced, two or more receivers are required in a visible area, and this technology requires a large number of receivers at a construction site where many areas are being built.

[0004] Patent Document 2 discloses a technology for transmitting signals from an end wireless station to a gateway wireless station in a wireless multi-hop network that transmits data between multiple devices by relaying radio waves like a bucket brigade. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-98749 A [Patent Document 2] Patent No. 4508053 Summary of the Invention [Problem to be solved by the invention]

[0006] At construction sites of commercial facilities and factories, construction materials, construction machinery, and other equipment are sometimes stored as temporary storage areas in areas of the interior floors where the interior partitions are not yet completed or where the equipment is completed. Every day, a large amount of materials are brought into the site and temporarily stored in each temporary storage area, but it is difficult to have someone else systematically recognize and remember the date, time, and location. At construction sites with large, multi-story indoor floors, the location of these materials and equipment must be visually confirmed by the on-site staff, which can result in a lot of man-hours spent searching for them.

[0007] Therefore, it is considered to use the technology of Patent Document 1 for detecting the position of materials and equipment at a construction site. In this case, in order to receive radio waves from multiple transmitters fixedly installed in each area of ​​a wide and multi-story indoor floor, it is necessary to increase the number of receivers installed in each area. As a countermeasure, it is possible to apply, for example, the wireless multi-hop network described in Patent Document 2 to the wireless network used in the position detection system, and to omit the transmission cable from the receiver. In this case, signals can be wirelessly transmitted by multi-hop communication from the terminal wireless station (slave) installed in the materials and equipment to the gateway wireless station (master).

[0008] However, when a wireless multi-hop network is applied to a location detection system for equipment, it is possible that the output signal of a terminal wireless station (slave) installed on the equipment may be received by multiple repeaters included in the wireless multi-hop network, which may make it difficult to accurately detect the location of the equipment.

[0009] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a position detection system that can prevent erroneous detection of the position of equipment and materials placed in a wide indoor area. [Means for solving the problem]

[0010] In order to solve the above problem, the first disclosure is applied to a position detection system that detects in which of a plurality of areas included in a target site a target equipment is placed. The position detection system has a slave unit installed in the target equipment, a plurality of relay units installed in each of the plurality of areas, and a master unit installed in the target site. The slave unit, the plurality of relay units, and the master unit are configured to wirelessly transmit transmission information from the slave unit to the master unit by multi-hop communication. The slave unit is configured to output transmission information including a unique address of its own node. The relay unit has a function of receiving transmission information and a function of further adding the unique address of its own node to the received transmission information and outputting the information. The master unit has a function of receiving transmission information and a function of further adding the unique address of its own node to the received transmission information and transmitting the information to a management server. The management server is configured to output a detection result of in which of a plurality of areas the target equipment is placed based on the transmission information. The transmission output of the slave unit is smaller than the transmission output of the relay unit.

[0011] The second disclosure further includes the following features in the first disclosure. The repeater and the slave unit are powered by built-in batteries, with the repeater having a transmission output of 10 mW to 20 mW and the slave unit having an output of 1 mW or less.

[0012] The third disclosure is the first or second disclosure further including the following features. The transmission frequencies of the slave and repeater are within the sub-gigahertz frequency band.

[0013] The fourth disclosure is any one of the first to third disclosures further comprising the following features. The management server is configured to identify a first node among a plurality of repeaters or parent devices that first relayed the transmission information output from a child device based on the transmission information, and to identify the area in which the first node is installed as the area in which the target equipment is located.

[0014] The fifth disclosure is any one of the first to fourth disclosures further comprising the following features. The management server is configured to output the detection result to a display device. The display device is configured to display a list of the locations of the target equipment and materials.

[0015] The sixth disclosure is any one of the first to fifth disclosures further comprising the following features. The management server is configured to output the detection result to a display device. The display device is configured to display the movement history of each of the target equipment and materials.

[0016] The seventh disclosure is any one of the first to sixth disclosures further comprising the following features. The repeater has an external antenna exposed to the outside of the housing, and the slave has an internal antenna disposed inside the housing. Effect of the Invention

[0017] According to the position detection system of the present disclosure, the output from the slave unit installed in the target equipment is easily transmitted only to the nearest repeater or master unit, which makes it possible to prevent erroneous detection of the position of the target equipment located in a wide indoor area. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing an overview of a position detection system according to an embodiment; [Diagram 2] 1 is a schematic diagram showing a topology of a wireless mesh network in a position detection system according to an embodiment; [Diagram 3] FIG. 1 is a block diagram showing a configuration of a position detection system 100. [Figure 4] FIG. 1 is a diagram illustrating an application example of the position detection system 100. [Diagram 5] 2 is a functional block diagram for explaining functions of a slave unit 12. FIG. [Figure 6] 2 is a functional block diagram for explaining functions of a repeater 10. FIG. [Figure 7] FIG. 2 is a functional block diagram for explaining the functions of a parent device 14. [Figure 8] FIG. 2 is a functional block diagram for explaining functions of a management server 20. [Figure 9] FIG. 4 is a diagram illustrating an example of transmission information stored in a storage device. [Figure 10] FIG. 11 is a diagram showing an example of repeater / parent device management information. [Figure 11] FIG. 4 is a diagram showing an example of child device management information. [Figure 12] 13 is a diagram showing an example of an equipment and materials position display screen displayed on the display device 32. FIG. [Figure 13] 13 is a diagram showing another example of the equipment and materials position display screen displayed on the display device 32. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. However, when the number, quantity, amount, range, etc. of each element is mentioned in the embodiments shown below, this disclosure is not limited to the mentioned number unless it is specifically stated or clearly specified in principle. Furthermore, the structures, etc. described in the embodiments shown below are not necessarily essential to this disclosure unless it is specifically stated or clearly specified in principle.

[0020] Embodiment 1. Overview of the position detection system FIG. 1 is a diagram showing an overview of a position detection system according to an embodiment. The position detection system 100 is a system for detecting the positions of materials and equipment placed on an indoor floor of a construction site. Examples of materials and equipment include building materials such as steel materials, construction machinery such as aerial work vehicles, and the like. The position detection system 100 shown in FIG. 1 is installed at a construction site having a wide indoor floor F. The wide indoor floor F is often a multi-story building, and is a space in which visibility is poor because partitions are changed every day during construction, and there are things that block radio waves such as concrete and steel structural materials. The position detection system 100 includes multiple repeaters 10, a slave unit 12, a master unit 14, and a management server 20.

[0021] The multiple repeaters 10 are nodes that constitute a wireless mesh network that uses a sub-gigahertz (920 MHz) frequency band as a transmission frequency. The wireless mesh network is a form of ad-hoc network that does not require an access point, and each node that constitutes the wireless mesh network performs multi-hop communication. Note that there are various known documents regarding multi-hop communication using a wireless mesh network, as shown in, for example, Patent Document 2, and therefore a detailed description thereof will be omitted here.

[0022] A plurality of repeaters 10 are fixedly installed on an indoor floor F at intervals for each assigned area. In the example shown in FIG. 1, repeaters 10a, 10b, 10c, and 10d are installed corresponding to the four rectangular areas Fa, Fb, Fc, and Fd of a rectangular indoor floor F. The indoor floor F is, for example, a rectangular floor of about 50 m square, and each of the areas Fa, Fb, Fc, and Fd is, for example, a rectangular floor of about 25 m square. A large number of repeaters 10 need to be installed, and since reception from the child device 12, which is the main data source, and transmission to the parent device 14, which is the data destination, are performed wirelessly, transmission cables and power cables can be omitted by having an internal power battery and operating it. This allows for a significant reduction in the cost of installation and relocation work.

[0023] The slave device 12 is a node that configures a wireless mesh network that uses a sub-gigahertz (920 MHz) frequency band as a transmission frequency, similar to the repeater device 10. The slave device 12 is also called an active tag because it has an internal battery as a power source and outputs radio waves by itself.

[0024] The slave units 12 are installed on materials and equipment placed on the indoor floor F. The target materials and equipment are those that may move within the indoor floor F. The materials and equipment are of course moved by construction machinery (such as aerial work vehicles), but materials also inevitably move as they are collected or dispersed depending on changes in temporary storage areas and the process of bringing in materials. Four slave units 12 are shown in FIG. 1. The materials and equipment are not shown in FIG. 1. There is no limit to the number of slave units 12 that are the target of position detection in the position detection system 100, as long as it is one or more.

[0025] The master device 14 is a gateway device having a function as a communication device that connects the wireless mesh network to an external communication network 16 such as the Internet, in addition to the data receiving function of the repeater 10. The master device 14 converts signals of the wireless mesh network, which is a Low Power Wide Area-network (LPWA), and is connected to the management server 20 via a wired LAN, WiFi, or the Internet. The management server 20 may be constructed as an on-premise system and then connected to the administrator terminal 30 via a LAN, or the management server 20 may be constructed in the cloud and then connected to the administrator terminal 30 via the Internet.

[0026] 2 is a schematic diagram showing a topology of a wireless mesh network in a position detection system according to an embodiment. The slave 12 periodically (for example, once per minute) outputs transmission information including the unique address of the node. The transmission information output from the slave 12 is received by the nearest repeater 10. The repeater 10 that receives the transmission information collects the RSSI value, which is the signal strength of the received transmission information, in association with the unique address of the node that sent it, and outputs the RSSI value with the unique address of the node that sent it. In this way, in the position detection system 100, the transmission information output from the slave 12 is transmitted to the master 14 by one or more repeaters 10 relaying the transmission information in turn by multi-hop communication. The master 14 transmits the received transmission information to the management server 20 via the external communication network 16.

[0027] The management server 20 has a function as a storage unit that stores the transmission information received from the parent device 14, a location management function that manages the location of the child device 12 based on the stored information, and a communication function that communicates with the user's terminal. The transmission information includes the unique address and RSSI value of the node relayed during transmission from the child device 12 to the parent device 14. The management server 20 detects the location of the child device 12 by setting the location area of ​​the first node relayed first from the child device 12 as the location of the child device 12, and transmits the detection result to the administrator terminal 30 of the administrator. The administrator terminal 30 is exemplified by a personal computer, a smartphone, a tablet, etc. equipped with a display device 32. The detection result is displayed on the display device 32 of the administrator terminal 30. This allows the administrator to grasp the location of the target equipment in which the child device 12 is installed.

[0028] Here, if the signal output from the slave 12 is received not only by the nearest repeater 10 but also by other repeaters 10, there is a risk of false detection. Therefore, in the position detection system 100 of this embodiment, a measure is taken to make it difficult for the signal output from the slave 12 to be received by multiple repeaters 10. Specifically, the repeater 10 of the position detection system 100 needs an output value for radio waves to reach other repeaters 10, whereas the slave 12 only needs a minimum output value for radio waves to reach the nearest repeater 10. For example, in an indoor floor F of about 50 m square in FIG. 1, the distance between the repeaters is a maximum of about 50 to 75 m, whereas the distance between the slave 12 and the nearest repeater 10 is a maximum of about 20 to 30 m.

[0029] Therefore, the output value of the transmission information of the slave 12 of the position detection system 100 is suppressed to a value smaller than the output value of the repeater 10. The output value of the slave 12 here is set to an output value that allows radio waves to reach only the nearest repeater 10, taking into consideration the installation interval of the repeaters 10 on the indoor floor F. For example, the transmission output of the repeater 10 is set to 10 mW to 20 mW, whereas the transmission output of the slave 12 is set to 1 mW or less. More preferably, the transmission output of the repeater 10 is set to 20 mW, and the transmission output of the slave 12 is set to 1 mW.

[0030] The above is an overview of the position detection system 100 of this embodiment. The position detection system 100 can prevent erroneous detection caused by multiple repeaters 10 receiving the output of the child device 12. This improves the accuracy of detecting the position of materials and equipment on a wide indoor floor. The configuration and functions of the position detection system 100 will be described in detail below.

[0031] 2. Configuration and Function of Position Detection System 100 3 is a block diagram showing the configuration of the position detection system 100. The position detection system 100 includes a plurality of relays 10, a child device 12, a parent device 14, a management server 20, and an administrator terminal 30. The child devices 12, the plurality of relays 10, and the parent device 14 constitute each node of a wireless mesh network, and realize multi-hop communication. The parent device 14 and the management server 20 are connected via an external communication network 16 such as an in-house LAN or the Internet. The management server 20 and the administrator terminal 30 are connected via a wireless or wired communication line.

[0032] FIG. 4 is a diagram showing an application example of the position detection system 100. This diagram illustrates an example in which the position detection system 100 is applied to a target site in which seven floors from the first basement floor (BF) to the sixth floor (6F) are each divided into four areas, A work area, B work area, C work area, and D work area. A plurality of repeaters 10 are installed corresponding to each work area on each floor. A master unit 14 is installed in the D work area on the sixth floor. A slave unit 12 is installed in each of a plurality of equipment and materials placed in the target site. In FIG. 4, the management server 20 and the manager terminal 30 are omitted from the illustration.

[0033] 5 is a functional block diagram for explaining the functions of the slave unit 12. The slave unit 12 constitutes a terminal node of the wireless mesh network. The slave unit 12 is installed on an indoor floor in a target equipment or material that is a target for position detection.

[0034] The slave unit 12 includes a wireless unit 121, a slave unit control unit 122, and a power supply unit 123. The wireless unit 121 is a functional block for performing wireless communication using a sub-gigahertz (920 MHz) frequency band, and includes an internal antenna 125 and a transmission unit 126 arranged inside the housing. The slave unit control unit 122 generates transmission information including the unique address of the node itself, and outputs the information periodically (for example, once per minute) from the transmission unit 126. The transmission output is set to 1 mW, which is derived from an experiment, so that the signal reachable range is limited to a maximum of about 20 m to 30 m. The internal antenna 125 is used to limit the signal reachable range. The power supply unit 123 uses an internal battery such as a dry cell for portability. By conducting wireless communication using the sub-gigahertz (920MHz) frequency band, data traffic is greater than with the 429MHz band used for specific low-power radio stations that has long been used, while data traffic is smaller than with the 2.4GHz band used for WiFi, etc., but radio wave reach is greater because it is less affected by obstructions. In this way, the sub-gigahertz (920MHz) frequency band is suitable for building wireless multi-hop networks for transmitting sensor information at construction sites, etc.

[0035] 6 is a functional block diagram for explaining the function of the repeater 10. A plurality of repeaters 10 constitute each node of the wireless mesh network. The plurality of repeaters 10 are fixedly installed at specific positions on an indoor floor. The specific positions here are, for example, positions that are determined in advance as positions spaced apart (for example, 50 m to 80 m) from each other so that they can communicate with each other on an indoor floor that is the subject of position detection.

[0036] The repeater 10 includes a radio unit 101, a repeater control unit 102, and a power supply unit 103. The radio unit 101 is a functional block for performing radio communication using a sub-gigahertz (920 MHz) frequency band, similar to the child device 12. The radio unit 101 includes an external antenna 105 exposed outside the housing, a transmitting unit 106, and a receiving unit 107. The receiving unit 107 receives transmission information transmitted from the child device 12 or another repeater 10. The repeater control unit 102 generates transmission information by further adding information related to the node to the received transmission information. Specifically, the repeater control unit 102 collects the signal strength (RSSI value) of the received transmission information, associates it with the unique address of the node from which it is sent, and adds it to the transmission information. The repeater control unit 102 also adds the unique address of the node to the transmission information. The repeater control unit 102 outputs the generated transmission information from the transmitting unit 106. To ensure a signal transmission range of about 80m to 100m, the transmission output of the repeater 10 is set to 10mW to 20mW, and more preferably 20mW. The external antenna 105 is for increasing the signal strength of the transmitted information. The power supply unit 103 may be a built-in battery such as a dry cell, or an external power supply. However, at construction sites where the installation environment is frequently changed, a built-in battery that can be easily moved is preferable.

[0037] 7 is a functional block diagram for explaining the functions of the master unit 14. The master unit 14 is fixedly installed at a specified position on an indoor floor. The specified position here is, for example, a position that is determined in advance as a position where communication with at least one repeater 10 is possible on an indoor floor that is the target of position detection.

[0038] The master unit 14 includes a radio unit 141, a master unit control unit 142, an external communication unit 143, and a power supply unit 144. The radio unit 141 is a functional block for performing radio communication using a sub-gigahertz (920 MHz) frequency band, similar to the repeater 10. The functions of the external antenna 145, the transmitting unit 146, and the receiving unit 147 included in the radio unit 141 are similar to those of the external antenna 105, the transmitting unit 106, and the receiving unit 107 included in the repeater 10. The master unit control unit 142 generates transmission information by further adding information related to its own node to the received transmission information. Specifically, the master unit control unit 142 collects the signal strength (RSSI value) of the received transmission information, associates it with the unique address of the node that is the source, and adds it to the transmission information. The master unit control unit 142 also adds the unique address of its own node to the transmission information.

[0039] The parent device control unit 142 outputs the generated transmission information from the external communication unit 143 to the management server 20 via an external communication network 16 such as a wired LAN, WiFi, or the Internet. The power supply unit 144 may be an internal battery such as a dry cell, or an external power supply.

[0040] FIG. 8 is a functional block diagram for explaining the function of the management server 20. The management server 20 is configured as a server on a cloud, for example. Alternatively, the management server 20 may be configured integrally with the administrator terminal 30. The management server 20 includes a control device 201 and a storage device 202. The storage device 202 stores the transmission information received from the parent device 14. FIG. 9 is a diagram showing an example of the transmission information stored in the storage device. As shown in this figure, the transmission information stores the unique addresses of the nodes relayed from the child device 12 to the parent device 14 and the RSSI values ​​at the time of transmission between each node. The control device 201 detects the position of the equipment in which the child device 12 is installed using the stored transmission information. For example, the control device 201 identifies the unique address of the node (first node) that first relayed the transmission information of the child device 12 based on the transmission information. The storage device 202 stores repeater / parent device management information indicating the installation locations of the multiple repeaters 10 and the parent device 14 in association with the unique addresses of the respective nodes. 10 is a diagram showing an example of repeater / parent management information. In the repeater / parent management information shown in this figure, a unique address is stored in association with the type of node and the floor and work area of ​​the installation location. The control device 201 reads out the installation location corresponding to the unique address of the first node from the repeater / parent management information, and identifies the floor and work area as the detection result of the position of the child device 12.

[0041] Further, in the storage device 202, child device management information showing information on the child devices 12 installed in the equipment is stored in association with each unique address. FIG. 11 is a diagram showing an example of child device management information. In the example shown in this figure, the child device management information stores the node type and detailed information on the equipment in association with the unique address. The control device 201 reads out the detailed information on the equipment corresponding to the unique address of the target child device 12 from the child device management information. Then, the control device 201 generates an equipment / materials position display screen showing the equipment / materials and their positions, and transmits it to the manager terminal 30. The manager terminal 30 displays the received equipment / materials position display screen on the display device 32. This enables the manager to check the positions of the equipment / materials in the work site at any time and from anywhere.

[0042] Fig. 12 is a diagram showing an example of an equipment / materials location display screen displayed on the display device 32. In this diagram, the floors and work areas on which each equipment / material on which a slave unit 12 is installed is displayed in a list. This type of display allows the location of each equipment / material to be grasped at a glance.

[0043] 13 is a diagram showing another example of the equipment location display screen displayed on the display device 32. In this diagram, the change over time in the movement history of each equipment in which a slave unit 12 is installed is displayed. This type of display makes it possible to grasp the movement history of each target equipment. [Explanation of symbols]

[0044] 10 Repeater 12 Child Unit 14 Parent unit 16 External communication network 20 Management Server 30 Administrator terminal 32 Display device 100 Position Detection System 101 Radio Section 102 Repeater control unit 103 Power supply section 105 External Antenna 106 Transmitter 107 Receiving section 121 Radio Section 122 Child unit control section 123 Power supply section 125 Internal Antenna 126 Transmitter 141 Radio Section 142 Parent unit control section 143 External Communications Department 144 Power supply section 145 External Antenna 146 Transmitter 147 Receiving section 201 Control device 202 Storage device

Claims

1. 1. A position detection system for detecting in which of a plurality of areas included in a target site a target material or equipment placed in the target site is located, The position detection system includes: A slave unit to be installed on the target equipment; A plurality of repeaters installed in each of the plurality of areas; A master unit is installed at the target site, the child device, the plurality of relay devices, and the parent device are configured to wirelessly transmit transmission information from the child device to the parent device by multi-hop communication; The child device is configured to output the transmission information including a unique address of the node itself; the repeater has a function of receiving the transmission information and a function of further adding a unique address of the node to the received transmission information and outputting the information; the parent device has a function of receiving the transmission information and a function of further adding a unique address of the own node to the received transmission information and transmitting the information to a management server; the management server is configured to output a detection result indicating in which of the plurality of areas the target equipment or materials is located based on the transmission information; The transmission output of the slave unit is smaller than the transmission output of the repeater unit. A position detection system comprising:

2. The repeater and the slave unit are operated by built-in batteries, The repeater has a transmission output of 10 mW to 20 mW; The output of the child unit is 1 mW or less.

2. The position detection system according to claim 1 .

3. The transmission frequency of the slave unit and the repeater is within the sub-gigahertz frequency band.

3. The position detection system according to claim 1 or 2.

4. The management server identifies a first node that first relayed the transmission information output from the child device among the plurality of relay devices or the parent device based on the transmission information, and identifies an area in which the first node is installed as an area in which the target equipment or materials are placed.

4. The position detection system according to claim 1, wherein the position detection system is configured as follows:

5. the management server is configured to output the detection result to a display device; The display device displays a list of the locations of the target equipment and materials.

5. The position detection system according to claim 1, wherein the position detection system is configured as follows:

6. the management server is configured to output the detection result to a display device; The display device displays the movement history of each of the target equipment and materials.

6. The position detection system according to claim 1, wherein the position detection system is configured as follows:

7. The repeater has an external antenna exposed outside a housing, The handset has an internal antenna disposed inside the housing.

7. The position detection system according to claim 1, wherein the position detection system comprises: a first detecting means for detecting a position of the vehicle;

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