Position detection system

Abstract

To provide a position detection system that can detect a position of a tracking target with high accuracy.SOLUTION: A position detection system 1 has: a beacon transmitter 3 that is attached to an employee Q and transmits a beacon signal 31; a cluster-type network CN; and an application device 6 that communicates with the beacon transmitter 3 via the cluster-type network CN. The beacon transmitter 3 includes an inertial sensor 33 and inputs inertial information 312 acquired by the inertial sensor 33 into the beacon signal 31 and transmits it. The cluster-type network CN has a plurality of third communication devices 5c that receives the beacon signal 31 and transmits report data 7 including an intensity 73 of the received beacon signal 31 and the inertial information 312. Further, the application device 6 detects a position of the employee Q on the basis of the report data 7 acquired through the cluster-type network CN.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a position detection system.

Background Art

[0002] For example, Patent Document 1 discloses a position detection system using beacons. The position detection system described in Patent Document 1 includes a plurality of receivers that transmit and receive a predetermined signal and are fixed at predetermined positions in space, a mobile beacon mounted on a moving body existing in space, and an information processing device capable of communicating with each receiver.

[0003] The mobile beacon transmits an electromagnetic wave (beacon signal) of circular polarization including mobile beacon identification information. Each receiver receives the electromagnetic wave transmitted from the mobile beacon, measures the reception intensity of the signal, and transmits the mobile beacon identification information, the receiver identification information, and the reception intensity to the information processing device. The information processing device calculates the position of the mobile beacon based on the mobile beacon identification information, the receiver identification information, the reception intensity, and the position information of the receiver transmitted from the receiver.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In such a position detection system, by making the electromagnetic wave transmitted by the mobile beacon circularly polarized, the influence of factors other than the distance of the reception intensity (for example, the orientation of the mobile beacon, etc.) is reduced, and the position detection accuracy of the mobile beacon is improved. However, even if the electromagnetic wave is circularly polarized, the position of the moving body cannot be detected with high accuracy by a method of detecting the position of the mobile beacon using only the reception intensity.

[0006] The present invention has been made in view of such a point, and an object thereof is to provide a position detection system capable of further improving the position detection accuracy of a tracking target by using inertial information generated in the tracking target (moving object) in addition to the reception intensity of a beacon signal (electromagnetic wave).

Means for Solving the Problems

[0007] Such an object is achieved by the present invention of the following (1).

[0008] (1) A beacon transmitter that moves together with a tracking target and transmits a beacon signal, A cluster type network, An application device that communicates with the beacon transmitter via the cluster type network, and The beacon transmitter includes an inertial sensor, and inserts inertial information acquired by the inertial sensor into the beacon signal and transmits it, The cluster type network includes a reception layer including a plurality of receivers that receive the beacon signal, measure the intensity of the received beacon signal, and transmit report data including the intensity and the inertial information, and a relay layer including a repeater that receives the report data transmitted by the receiver and transmits it to the application device, The application device is characterized in that it detects the position of the tracking target based on the intensity and the inertial information included in the report data acquired via the relay layer.

Effects of the Invention

[0009] In the position detection system of the present invention, the application device detects the position of the tracking target based on the intensity of the beacon signal and the inertial information included in the report data. In this way, by detecting the position of the tracking target using inertial information in addition to the reception intensity of the beacon signal, the position detection accuracy of the tracking target is improved as compared with the case of detecting the position of the tracking target using only the reception intensity of the beacon signal.

Brief Description of the Drawings

[0010]

Figure 1

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, the position detection system of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

[0012] FIG. 1 is a diagram showing the overall configuration of a position detection system according to a preferred embodiment. FIG. 2 is a diagram showing an example of applying the position detection system shown in FIG. 1 to a position detection system for employees in an office. FIG. 3 is a graph showing an example of a detection signal output from an inertial sensor when an employee performs a sitting operation. FIG. 4 is a graph showing an example of a detection signal output from an inertial sensor when an employee performs a standing-up operation. FIG. 5 is a graph showing an example of a detection signal output from an inertial sensor when an employee performs a walking operation. FIG. 6 is a diagram showing the configuration of a beacon signal. FIG. 7 is a diagram showing the configuration of report data. FIG. 8 is a diagram showing an example cited to explain the operation of a position detection module provided in an application device. FIG. 9 is a diagram for explaining a mechanism for detecting the position of a beacon transmitter by triangulation. FIG. 10 is a diagram showing an example cited to explain the operation of a position detection module provided in an application device.

[0013] The position detection system 1 shown in FIG. 1 has a function of detecting the position of a tracking target within a specific position detection area. Application examples of such a position detection system 1 are not particularly limited. For example, the position detection system 1 can be applied to the position detection of employees (tracking targets) within an office (position detection area). Also, the position detection system 1 can be applied to the position detection of students and teachers (tracking targets) within a school (position detection area), the position detection of patients, doctors, nurses (tracking targets), etc. within a hospital (position detection area), etc. Also, the position detection system 1 can be applied to the position detection of shoppers (tracking targets) within the floor or sales floor (position detection area) of a retail store such as a supermarket or a department store. Also, the position detection system 1 can be applied to the position detection of an automated guided vehicle (tracking target) within a warehouse (tracking target).

[0014] In the following, for convenience of explanation, as shown in FIG. 2, the case where the position detection system 1 is applied to the position detection of an employee Q (tracking target) within an office (position detection area) where a large number of work seats D are arranged will be described representatively.

[0015] Returning to FIG. 1, the position detection system 1 includes a beacon transmitter 3 worn by the employee Q and moving with the employee Q, a cluster-type network CN, and an application device 6 communicating with the beacon transmitter 3 via the cluster-type network CN. Hereinafter, each part constituting the position detection system 1 will be described in order.

[0016] ≪Beacon Transmitter 3≫ The beacon transmitter 3 is worn by the employee Q as a tracking target and moves with the employee. Therefore, the position of the beacon transmitter 3 can be regarded as the position of the employee Q in the office. Note that the wearing location of the beacon transmitter 3 is not particularly limited, but it is preferably worn on the upper body, particularly on the chest, or on the helmet when the helmet is worn. Thereby, the inclination of the upper body of the employee Q can be detected by an inertial sensor 33 described later provided in the beacon transmitter 3, and the movement of the employee Q can be detected in more detail.

[0017] As shown in FIG. 1, the beacon transmitter 3 has a function of consuming the power of a secondary battery (not shown) provided therein and transmitting a beacon signal 31 conforming to the BLE (Bluetooth (registered trademark) Low Energy) standard at a predetermined transmission frequency (for example, every 100 milliseconds). The beacon transmitter 3 includes a BLE communication unit 32 configured to perform wireless communication conforming to the BLE standard, an inertial sensor 33 that detects the inertia generated in the beacon transmitter 3, and a state detection unit 34 that detects the operation of the employee Q based on the output signal of the inertial sensor 33.

[0018] The inertial sensor 33 is used to detect the operations (amount of movement and state, to be described later) of the worker Q. The inertial sensor 33 is a six-axis inertial sensor and can independently detect the acceleration in the axial directions of each of the three mutually orthogonal axes, namely the X-axis, Y-axis, and Z-axis, and the angular velocity around each axis. Note that the beacon transmitter 3 is attached to the worker Q such that the X-axis is along the front-rear direction of the worker Q, the Y-axis is along the left-right direction of the worker Q, and the Z-axis is along the up-down direction of the worker Q. Therefore, it is preferable that the beacon transmitter 3 is provided with a mark indicating the mounting posture.

[0019] In this way, by using a six-axis inertial sensor as the inertial sensor 33, the translational motion (straight-line motion) of the worker Q can be detected based on the acceleration signals of the three orthogonal axes, and the rotational motion (direction change) of the worker Q can be detected based on the angular velocity signals of the three orthogonal axes. Therefore, it is possible to detect in which direction, at what speed, and how far the worker Q has advanced, and further, how the worker Q has changed the posture, and the operations of the worker Q can be detected with higher accuracy. Note that the detected operations of the worker Q are suitably used when detecting the position of the worker Q, as will be described later.

[0020] However, the inertial sensor 33 is not particularly limited as long as it can detect at least one acceleration or angular velocity.

[0021] Here, when the output value of the inertial sensor 33 is below the lower threshold for a certain period of time or more, it can be determined that the beacon transmitter 3 is not worn by the employee Q and the beacon transmitter 3 is not being used. In this case, the beacon transmitter 3 stops transmitting the beacon signal 31. On the other hand, when the output value of the inertial sensor 33 becomes equal to or higher than the upper threshold while the beacon transmitter 3 is in a state of stopping the transmission of the beacon signal 31, it can be determined that the beacon transmitter 3 is worn by the employee Q and the use of the beacon transmitter 3 has been started. In this case, the beacon transmitter 3 starts transmitting the beacon signal 31. In this way, by determining the output value of the inertial sensor 33 and controlling the start and stop of the transmission of the beacon signal 31, the beacon signal 31 can be transmitted only when the beacon transmitter 3 is being used by the employee Q, and the power consumption of the secondary battery of the beacon transmitter 3 can be suppressed.

[0022] The state detection unit 34 is composed of, for example, a computer, and has one or more processors for processing information and a memory communicably connected to the processors.

[0023] The one or more processors are arithmetic units that execute arithmetic processing such as signal operations based on computer-readable instructions, such as one or more microprocessors, microcomputers, microcontrollers, digital signal processors (DSPs), central processing units (CPUs), memory control units (MCUs), graphics processing units (GPUs) for image processing, state machines, logic circuits, application-specific integrated circuits (ASICs), or combinations thereof. In particular, the processor is configured to fetch computer-readable instructions (such as data, programs, etc.) stored in the memory and execute arithmetic operations, signal operations, and control.

[0024] The memory is a computer-readable medium including, for example, a volatile memory medium (e.g., RAM, SRAM, DRAM), a non-volatile memory medium (e.g., ROM, EPROM, EEPROM, flash memory, hard disk, solid state drive, optical disk, CD-ROM, digital versatile disk (DVD), Blu-ray disk, magnetic cassette, magnetic tape, magnetic disk), or a combination thereof. Such a memory is communicably connected to a processor and stores programs and data executable by the processor. The processor reads and executes the programs stored in the memory.

[0025] The state detection unit 34 processes the detection signals output from the inertial sensor 33 for each measurement period to detect the movement amount of the worker Q. Specifically, the state detection unit 34 detects the translational motion (straight movement) of the worker Q based on the acceleration signals of three orthogonal axes and detects the rotational motion (direction change) of the worker Q based on the angular velocity signals of three orthogonal axes. Then, the movement amount of the worker Q is detected based on the detected translational motion and rotational motion. Specifically, it is detected in which direction, at what speed, and how far the worker Q has advanced. According to such a method, the movement of the worker Q can be detected more accurately.

[0026] In addition, the state detection unit 34 detects the state of the worker Q based on the waveform of the detection signal output from the inertial sensor 33 for each measurement period. Specifically, the state detection unit 34 determines whether the worker Q is in a stopped state of sitting at the work seat D and stopped or in a moving state of walking and moving.

[0027] Specifically, FIG. 3 shows an example of a detection signal output from the inertial sensor 33 when the employee Q takes a seat at the work seat D. FIG. 4 shows an example of a detection signal output from the inertial sensor 33 when the employee Q stands up from the work seat D. FIG. 5 shows an example of a detection signal output from the inertial sensor 33 when the employee Q is walking. Each of these figures shows the acceleration signal in the Z-axis direction output from the inertial sensor 33 during each operation, the velocity signal in the Z-axis direction obtained by integrating the acceleration in the Z-axis direction, and the pitch angle (tilt of the Z-axis) signal of the Z-axis obtained from the angular velocity signal around the Y-axis. And it can be seen that different characteristics appear in the waveforms of the detection signals during the sitting, standing up, and walking operations. Therefore, the state detection unit 34 discriminates the state (stopped state / moving state) of the employee Q based on the waveforms of these signals.

[0028] As can be seen from FIGS. 3 to 5, when comparing the acceleration signals in the Z-axis direction during the sitting, standing up, and walking operations, only the walking operation has a periodic waveform. Therefore, if the acceleration signal in the Z-axis direction has a periodic waveform, the state detection unit 34 determines that the employee Q is performing a walking operation. Note that the same relationship also exists for the velocity signal in the Z-axis direction among the sitting, standing up, and walking operations. Therefore, the state detection unit 34 may also determine the walking operation based on the velocity signal in the Z-axis direction.

[0029] Also, when comparing the velocity signals in the Z-axis direction during the sitting and standing up operations, the waveforms are inverted up and down from each other. Therefore, if the velocity signal in the Z-axis direction has a waveform convex downward, the state detection unit 34 determines that the employee Q has performed a sitting operation. Conversely, if the waveform is convex upward, the state detection unit 34 determines that the employee Q has performed a standing up operation.

[0030] Then, the state detection unit 34 determines that the time from when the sitting motion is detected until the walking motion is detected after the standing motion is the stop state in which the employee Q is sitting and stopped at the work seat D, and determines that the time from when the walking motion is detected until the sitting motion is detected is the moving state in which the employee Q leaves the work seat D and moves within the office. Note that the above determination can be made using, for example, a decision tree (prediction model) generated by machine learning. This enables highly accurate determination.

[0031] The state detection unit 34 stores the motion (movement amount and state) of the employee Q detected as described above as inertial information 312.

[0032] Although the method for detecting the motion of the employee Q has been described above, the method is not particularly limited.

[0033] The BLE communication unit 32 is a unit used to execute wireless communication according to the BLE standard. The BLE communication unit 32 includes components necessary to execute wireless communication according to the BLE standard, such as an antenna, a transmission / reception circuit, and a modulation / demodulation circuit, and wirelessly transmits the beacon signal 31 according to the BLE standard. The transmission period of the beacon signal 31 is not particularly limited, but is preferably about 50 milliseconds to 200 milliseconds, for example. Note that arbitrary data and information can be incorporated into the beacon signal 31. Therefore, as shown in FIG. 6, the beacon transmitter 3 incorporates various information necessary for detecting the position of the employee Q, such as the identification information 311 for identifying the beacon transmitter 3 from other beacon transmitters 3 and the inertial information 312 obtained by the state detection unit 34, into the beacon signal 31 and transmits it.

[0034] The above has described the beacon transmitter 3. However, the configuration of the beacon transmitter 3 is not particularly limited as long as it can transmit a beacon signal and measure inertia. For example, the BLE communication unit 32 and the inertial sensor 33 may be separate entities. Also, in this embodiment, the state detection unit 34 generates the inertial information 312, but the application device 6 may be provided with the functions of the state detection unit 34. That is, the output signal of the inertial sensor 33 may be transmitted from the beacon transmitter 3, and the application device 6 may generate the inertial information 312 based on the output signal of the inertial sensor 33. Similarly, the communication device 5 included in the cluster type network CN may be provided with the functions of the state detection unit 34. That is, the output signal of the inertial sensor 33 may be transmitted from the beacon transmitter 3, and the communication device 5 may generate the inertial information 312 based on the output signal of the inertial sensor 33.

[0035] ≪Cluster Type Network CN≫ Returning to FIG. 1, the cluster type network CN includes one communication device 5 belonging to the primary layer which is the topmost layer (hereinafter also referred to as "primary communication device 5a"), and two communication devices 5 belonging to the secondary layer one level below the primary layer and connected so as to hang from the primary communication device 5a (hereinafter also referred to as "secondary communication devices 5b"), and four communication devices 5 belonging to the tertiary layer one level below the secondary layer and connected so as to hang from the secondary communication devices 5b (hereinafter also referred to as "tertiary communication devices 5c"). In the cluster type network CN, a plurality of communication devices 5 belonging to the same layer are not directly connected to each other.

[0036] In such a cluster type network CN, communication between layers is possible by relaying the communication devices 5 belonging to a higher layer or a lower layer than itself. Thus, in this specification, a network topology having a multi-layer structure is referred to as a "cluster type network". According to such a cluster type network CN, the construction, expansion, management, etc. of the position detection system 1 become easy.

[0037] In the cluster-type network CN, the connection between communication devices 5 is a pairing connection compliant with the BLE standard. The pairing connection enables two-way communication using wireless communication between a pair of paired devices. In the pairing connection, two devices transmit advertisement signals to each other, register each other's pairing information, and then establish a pairing connection between the two devices. In this way, a pair of devices connected to each other by the pairing connection can communicate with each other.

[0038] Such a cluster-type network CN is used to comprehensively control all communication devices 5 included in the cluster-type network CN with one application device 6.

[0039] For example, when the application device 6 transmits a signal targeted at a predetermined third-level communication device 5c belonging to the lowest third-level hierarchy to a primary communication device 5a belonging to the highest primary hierarchy of the cluster-type network CN, the communication devices 5 belonging to each hierarchy of the cluster-type network CN relay the signal transmitted from the application device 6 to an appropriate communication device 5 belonging to a hierarchy lower than itself and transmit it to the predetermined third-level communication device 5c. As a result, the predetermined third-level communication device 5c can receive the signal targeted at itself.

[0040] Conversely, when the third-level communication device 5c transmits a signal targeted at the application device 6 to a second-level communication device 5b belonging to the second-level hierarchy one level above, the communication devices 5 belonging to each hierarchy of the cluster-type network CN relay the signal transmitted from the third-level communication device 5c to an appropriate communication device 5 belonging to a hierarchy higher than itself and transmit it to the application device 6. As a result, the application device 6 can receive the signal targeted at itself.

[0041] Thus, in the cluster-type network CN, in order to enable two-way communication using wireless communication between a pair of paired communication devices 5, not only can signals be transmitted from a communication device 5 belonging to the upper layer to a communication device 5 belonging to the lower layer, but also signals can be transmitted from a communication device 5 belonging to the lower layer to a communication device 5 belonging to the upper layer.

[0042] Also, in the position detection system 1, a cluster-type network CN is constructed by connecting communication devices 5 of the same type (same hardware) to each other by pairing connections according to the BLE standard, and a plurality of communication devices 5 are comprehensively controlled via the cluster-type network CN. Therefore, in order to control each communication device 5, there is no need to construct a dedicated network using a plurality of types of dedicated devices such as a dedicated gateway or a dedicated server. Thus, the introduction cost of the position detection system 1 can be significantly reduced. In addition, since the cluster-type network CN is constructed only with communication devices 5 of the same type, the management of the position detection system 1 becomes easier compared to the case of constructing a network using a plurality of types of dedicated devices.

[0043] In the cluster-type network CN, each third-layer communication device 5c belonging to the lowest third layer functions as an end receiver unit, receives the beacon signal 31 transmitted from the beacon transmitter 3, and generates report data 7 regarding the intensity of the beacon signal 31. Further, each second-layer communication device 5b belonging to the second layer functions as a reporter unit, receives the report data 7 from each paired third-layer communication device 5c, and transmits it to the first-layer communication device 5a. Also, the first-layer communication device 5a belonging to the first layer functions as a master reporter unit, receives the report data 7 from each paired second-layer communication device 5b, and transmits it to the application device 6. That is, in the cluster-type network CN, the third layer is the receiving layer L1, and each communication device 5 belonging to the third layer functions as a receiver that receives the beacon signal 31. Further, the first layer and the second layer are relay layers L2, and each communication device 5 belonging to the first layer and the second layer functions as a relay that relays the transmission and reception of signals.

[0044] As shown in FIG. 2, nine third-layer communication devices 5c are regularly installed at regular intervals within the office and receive the beacon signal 31 of the beacon transmitter 3. As a result, the third-layer communication devices 5c are evenly arranged throughout the office, and the beacon signal 31 can be received more reliably from any position within the office. In the illustrated example, nine third-layer communication devices 5c are installed in a grid pattern at regular intervals (for example, 5 m intervals) within the office. And, the office is divided into four domains D1 to D4 by the nine third-layer communication devices 5c installed in a grid pattern. Also, the coordinate information of the installation location where each third-layer communication device 5c is arranged is stored in the third-layer communication device 5c itself.

[0045] Note that the arrangement of the plurality of third-layer communication devices 5c is not particularly limited. For example, a plurality of third-layer communication devices 5c may be arranged at one installation location. In this case, a third-layer communication device 5c facing east, a third-layer communication device 5c facing west, a third-layer communication device 5c facing north, and a third-layer communication device 5c facing south may be installed at one installation location.

[0046] When each of the third communication devices 5c receives the beacon signal 31 of the beacon transmitter 3, it refers to the received beacon signal 31 and the reception time of the beacon signal 31, and creates report data 7 regarding the intensity of the received beacon signal 31. Then, the created report data 7 is transmitted to the secondary communication device 5b that is paired and connected to itself. Each secondary communication device 5b is arranged at a location where communication with the third communication device 5c paired and connected to itself is possible, and transmits the report data 7 received from the third communication device 5c to the primary communication device 5a. The primary communication device 5a is arranged at a location where communication with each secondary communication device 5b paired and connected to itself is possible, and transmits the report data 7 received from the secondary communication device 5b to the application device 6.

[0047] Here, as shown in FIG. 7, the report data 7 includes the identification information 71 of the third communication device 5c, the installation location information 72 of the third communication device 5c, the intensity (RSSI: Received Signal Strength Indication) 73 of the received beacon signal 31, the reception time 74 of the beacon signal 31, and various information (the identification information 311 and the inertial information 312 of the beacon transmitter 3) included in the received beacon signal 31. The identification information 71 of the third communication device 5c is identification information for distinguishing it from other communication devices 5. The installation location information 72 is information for specifying the installation location of the third communication device 5c, and is, for example, coordinates within an office.

[0048] Returning to FIG. 2, each communication device 5 is an arbitrary information terminal capable of performing wireless communication based on the BLE standard, such as a tablet computer, a smartphone, or a PDA. Each communication device 5 is, for example, composed of a computer, and has one or more processors 51 for executing the control of the communication device 5, a BLE communication unit 53 for performing wireless communication according to the BLE standard, and one or more memories 54 for storing data and modules used for executing the processing of the communication device 5.

[0049] One or more processors 51 are arithmetic units that execute arithmetic processing such as signal operations based on computer-readable instructions such as one or more microprocessors, microcomputers, microcontrollers, digital signal processors (DSPs), central processing units (CPUs), memory control units (MCUs), graphics processing units (GPUs) for image processing, state machines, logic circuits, application-specific integrated circuits (ASICs), or combinations thereof. In particular, the processor 51 is configured to fetch computer-readable instructions (e.g., data, programs, modules, etc.) stored in the memory 54 and execute arithmetic operations, signal operations, and control.

[0050] The BLE communication unit 53 is a unit used to perform wireless communication according to the BLE standard, similar to the BLE communication unit 32 of the beacon transmitter 3. The BLE communication unit 53 includes components necessary to perform wireless communication according to the BLE standard, such as an antenna, a transceiver circuit, and a modulation / demodulation circuit. In response to control from the processor 51, it performs wireless communication according to the BLE standard with the application device 6 and other communication devices 5. By using the BLE communication unit 53, the communication device 5 can transmit and receive signals with the application device 6 and other communication devices 5.

[0051] Furthermore, the BLE communication unit 53 is capable of receiving the beacon signal 31 transmitted according to the BLE standard from the BLE communication unit 32 of the beacon transmitter 3. As described above, the beacon signal 31 transmitted from the beacon transmitter 3 at regular time intervals contains identification information 311 and inertial information 312. Therefore, by receiving the beacon signal 31 using the BLE communication unit 53, the communication device 5 can obtain the identification information 311 and inertial information 312 of the beacon transmitter 3 embedded in the beacon signal 31. The received beacon signal 31 is associated with the reception time 74 of the beacon signal 31 and temporarily stored in the memory 54 of the communication device 5.

[0052] In this way, the communication device 5 can receive the beacon signal 31 transmitted from the beacon transmitter 3 using the BLE communication unit 53. The intensity of the beacon signal 31 received by the BLE communication unit 53 of the communication device 5 is inversely proportional to the separation distance between the beacon transmitter 3 and the communication device 5. Therefore, by referring to the intensity 73 of the beacon signal 31 (Received Signal Strength Indication: RSSI), the separation distance between the beacon transmitter 3 and the communication device 5 that has received the beacon signal 31 can be calculated.

[0053] The memory 54 is a computer-readable medium including, for example, a volatile storage medium (e.g., RAM, SRAM, DRAM), a non-volatile storage medium (e.g., ROM, EPROM, EEPROM, flash memory, hard disk, solid state drive, optical disk, CD-ROM, digital versatile disk (DVD), Blu-ray disk, magnetic cassette, magnetic tape, magnetic disk), or a combination thereof. Such a memory 54 is communicably connected to the processor 51 and stores programs and data executable by the processor 51. The processor 51 reads and executes the programs stored in the memory 54.

[0054] The memory 54 is communicably connected to the processor 51 and stores data necessary for the communication device 5 to execute processes and a plurality of modules executable by the processor 51. Further, the memory 54 has a function of temporarily storing data received, processed, and generated by one or more of the plurality of modules and data necessary to execute processes by the plurality of modules.

[0055] The modules stored in the memory 54 are computer-readable instructions executable by the processor 51, such as routines, applications, programs, algorithms, libraries, objects, components, data structures, or combinations thereof. For example, the modules include an information transmission module for transmitting a signal including its own identification information 71, a network construction module for establishing a pairing connection for constructing a cluster type network CN, and a beacon signal processing module for calculating the intensity 73 of the beacon signal 31 received from the beacon transmitter 3 when the communication device 5 functions as a tertiary communication device 5c.

[0056] The above describes the cluster-type network CN. However, the configuration of the cluster-type network CN is not particularly limited as long as it includes the communication device 5 belonging to the reception layer L1 and the communication device 5 belonging to the relay layer L2. For example, in this embodiment, one primary communication device 5a belongs to the primary layer, but the number of primary communication devices 5a is not particularly limited and may be two or more. Also, three secondary communication devices 5b belong to the secondary layer, but the number of secondary communication devices 5b is not particularly limited. Further, two secondary communication devices 5b are connected to one primary communication device 5a, but the number of secondary communication devices 5b connected to one primary communication device 5a is not particularly limited. Also, nine tertiary communication devices 5c belong to the tertiary layer, but the number of tertiary communication devices 5c is not particularly limited. Further, three tertiary communication devices 5c are connected to one secondary communication device 5b, but the number of tertiary communication devices 5c connected to one secondary communication device 5b is not particularly limited. Also, the cluster-type network CN may have a structure including at least one communication device 5 belonging to a deeper layer such as a fourth layer which is one layer below the tertiary layer, at least one communication device 5 belonging to a fifth layer which is one layer below the fourth layer, and so on. The number of layers of the cluster-type network CN, the number of communication devices 5 belonging to each layer, and the number of communication devices 5 connected in a hanging manner to one communication device 5 can be appropriately set according to, for example, the number of necessary communication devices 5, the maximum connection number of each communication device 5, etc.

[0057] ≪Application Device 6≫ The application device 6 is any information terminal such as a desktop computer, laptop computer, notebook computer, workstation, tablet computer, mobile phone, smartphone, PDA, etc. Such an application device 6 detects the position of the worker Q based on the report data 7 received via the primary communication device 5a that is paired and connected so as to hang on itself.

[0058] As shown in FIG. 2, the application device 6 includes one or more processors 61 for executing control of the application device 6, a BLE communication unit 63 for performing wireless communication according to the BLE standard, and one or more memories 64 that store data and modules used for executing processing of the application device 6.

[0059] Similar to the processor 51 of the communication device 5, the one or more processors 61 are arithmetic units that execute arithmetic processing such as signal operation based on computer-readable instructions. Similar to the BLE communication unit 53 of the communication device 5, the BLE communication unit 63 is a unit used for performing wireless communication according to the BLE standard. By using the BLE communication unit 63, the application device 6 can perform wireless communication according to the BLE standard with the primary communication device 5a.

[0060] Similar to the memory 54 of the communication device 5, the memory 64 is a computer-readable medium including a volatile storage medium, a non-volatile storage medium, or a combination thereof. The memory 64 is communicably connected to the processor 61 and stores data necessary for the application device 6 to execute processing and a plurality of modules executable by the processor 61. Further, the memory 64 has a function of temporarily storing data received, processed, and generated by one or more of the plurality of modules and data necessary for executing processing by the plurality of modules.

[0061] The modules stored in the memory 64 are computer-readable instructions executable by the processor 61, such as routines, applications, programs, algorithms, libraries, objects, components, data structures, or combinations thereof. For example, the module includes a position detection module 661 for detecting the position of the employee Q at each time based on the report data 7 received from the tertiary communication device 5c via the primary communication device 5a, and a movement line creation module 662 for creating a movement line of the employee Q based on the position of the employee Q at each time detected by the position detection module 661.

[0062] An example showing the operation of the position detection module 661, that is, an example of detecting the beacon transmitter 3a attached to the employee Qa, will be described with reference to FIG. 8. The position detection module 661 first receives the report data 7 from each of the plurality of tertiary communication devices 5c via the primary communication device 5a. Next, the position detection module 661 picks up the report data 7 regarding the beacon transmitter 3a from among them.

[0063] Next, the position detection module 661 sorts the report data 7 for each time by referring to the intensity 73 of the beacon signal 31 included in the picked-up report data 7. Thereafter, the position detection module 661 refers to the intensity 73 of the beacon signal 31 included in the report data 7 sorted for each time, and at each time (for example, every second), sorts the list of the tertiary communication devices 5c in descending order of the intensity 73 of the received beacon signal 31, and picks up the top 4 tertiary communication devices 5c in the sorted list. That is, the position detection module 661 picks up the 4 tertiary communication devices 5c in ascending order of the distance from the beacon transmitter 3a.

[0064] Thereafter, the position detection module 661 identifies the domain defined by the four tertiary communication devices 5c picked up at each time from the identification information 71 and installation location information 72 of the four tertiary communication devices 5c. In the example shown in FIG. 8, the position detection module 661 identifies that the beacon transmitter 3a is located within the domain D3.

[0065] Next, the position detection module 661 arbitrarily selects three of the four tertiary communication devices 5c that define the identified domain D3. Then, based on the intensity 73 of the beacon signal 31 included in the report data 7 of each selected tertiary communication device 5c, the position detection module 661 uses triangulation (three-point positioning) to detect a provisional position (hereinafter also referred to as "provisional position") of the beacon transmitter 3a.

[0066] For example, when the heights of the tertiary communication devices 5cA, 5cB, and 5cC are the same, as shown in FIG. 9, the two-dimensional coordinates Pa of the tertiary communication device 5cA are (xa, ya), the two-dimensional coordinates Pb of the tertiary communication device 5cB are (xb, yb), the two-dimensional coordinates Pc of the tertiary communication device 5cC are (xc, yc), the two-dimensional coordinates P of the beacon transmitter 3a are (x, y), the distance between the tertiary communication device 5cA and the beacon transmitter 3a is Ra, the distance between the tertiary communication device 5cB and the beacon transmitter 3a is Rb, and the distance between the tertiary communication device 5cC and the beacon transmitter 3a is Rc, the distances Ra, Rb, and Rc are represented by the following equations (1), (2), and (3).

[0067] Ra = { (xa - x) 2 + (ya - y) 2} 1 / 2 …(1) Rb = { (xb - x) 2 + (yb - y) 2} 1 / 2 …(2) Rc = { (xc - x) 2 + (yc - y) 2} 1 / 2 …(3)

[0068] Here, let the intensity 73 of the beacon signal 31 included in the report data 7 of the tertiary communication device 5cA be Ea, the intensity 73 of the beacon signal 31 included in the report data 7 of the tertiary communication device 5cB be Eb, and the intensity 73 of the beacon signal 31 included in the report data 7 of the tertiary communication device 5cC be Ec. Since the intensity 73 of the beacon signal is inversely proportional to the distance, Ea:Eb:Ec = 1 / Ra:1 / Rb:1 / Rc. Therefore, the position detection module 661 substitutes the intensity 73 included in the report data 7 into the equations (1), (2), and (3) to detect the two-dimensional coordinates P(x, y) of the beacon transmitter 3a. In this way, by using the triangulation method, the provisional position of the beacon transmitter 3a can be easily detected.

[0069] Note that in this embodiment, before specifying the provisional position of the beacon transmitter 3a by the triangulation method, the position detection module 661 performs statistical processing on the intensity 73 of the beacon signal 31 included in the report data 7 in advance based on the average value, standard deviation, maximum value, minimum value, median value, threshold value, etc. of the entire data, and excludes abnormal values. Therefore, abnormal values of the intensity 73 are not used for the position detection of the beacon transmitter 3a, and the position detection accuracy of the beacon transmitter 3a is improved.

[0070] Note that if the relationship between the distance R between the tertiary communication device 5c and the beacon transmitter 3a and the received intensity E (for example, R = A / E, where A is a constant) has been obtained by statistical processing or the like in advance, the position detection module 661 can obtain the two-dimensional coordinates P of the beacon transmitter 3a, that is, the provisional position, from the two-dimensional coordinates of the two tertiary communication devices 5c selected from the four tertiary communication devices 5c that define the domain D3 and the intensity 73 of the beacon signal 31 at these two tertiary communication devices 5c.

[0071] Here, as described in the prior art, in the method of detecting the position of the beacon transmitter 3a using only the intensity 73 of the beacon signal 31, the position detection accuracy of the beacon transmitter 3a is degraded by factors other than the distance R, such as the orientation of the tertiary communication device 5c and the presence or absence of obstacles between the beacon transmitter 3a and the tertiary communication device 5c. Therefore, the position detection module 661 corrects the provisional position of the beacon transmitter 3a detected using only the intensity 73 of the beacon signal 31, further using the inertial information 312 included in the report data 7.

[0072] Specifically, the position detection module 661 picks up the amount of movement of the beacon transmitter 3a from the inertial information 312 included in the report data 7, and corrects the provisional position based on the picked-up amount of movement. For example, the position detection module 661 determines the amount of movement of the beacon transmitter 3a between time k-1 and time k obtained from the difference between the provisional position of the beacon transmitter 3a at the current period (time k) and the position of the beacon transmitter 3a at the previous period (time k-1) immediately before time k (the position after Kalman filter correction described later), and corrects the provisional position based on the deviation between the amount of movement of the beacon transmitter 3a between time k-1 and time k obtained from the inertial information 312. In this way, by correcting the provisional position using the inertial information 312, the position of the beacon transmitter 3a can be detected more accurately. Hereinafter, the position of the beacon transmitter 3a after correction by correcting the provisional position based on the inertial information 312 is also referred to as the observation position.

[0073] Furthermore, the position detection module 661 performs Kalman filter correction using the observed position. Specifically, the position detection module 661 corrects the position of the beacon transmitter 3a using the state estimation formula represented by the following formula (4). That is, the position of the beacon transmitter 3a at the current period (time k) is calculated based on the predicted estimated position of the beacon transmitter 3a at the current period (time k) predicted based on the position of the beacon transmitter 3a up to the previous period (time k-1), the Kalman gain, the observed position of the beacon transmitter 3a at the current period (time k), and the prior estimated position of the position of the beacon transmitter 3a at the current period (time k) based on the observed position of the beacon transmitter 3a up to the previous period (time k-1). In this way, by using, as the observed position used for Kalman filter correction, a value obtained by correcting the provisional position based on the inertial information 312, the output prediction error can be reduced, and the position (xk) of the beacon transmitter 3a at the current period (time k) can be accurately corrected (estimated). The position corrected in this way is determined as the position of the beacon transmitter 3a.

[0074]

Number

[0075] Furthermore, the position detection module 661 varies the value of the Kalman gain based on the state (stopped state / moving state) of the worker Qa included in the inertial information 312. Specifically, in the stopped state, since the beacon transmitter 3a does not move, the output prediction error can be kept small. In contrast, in the moving state, since the beacon transmitter 3a moves, the output prediction error is more likely to be larger than in the stopped state. Therefore, in the present embodiment, the Kalman gain in the stopped state is set to be larger than the Kalman gain g(k) in the moving state. That is, separate state estimation formulas with different Kalman gains are prepared for the stopped state and the moving state, and the state estimation formula is selectively used according to the state. Thereby, an optimal state estimation formula can be used according to the state of the worker Qa, and the position of the beacon transmitter 3a can be detected with higher accuracy.

[0076] Furthermore, for example, as shown in FIG. 10, when the work seat D is located at or near the position where the employee Qa has stopped, the position detection module 661 determines that the employee Qa is seated at the nearest work seat D, and fixes the position of the employee Qa to the coordinates of the work seat D. According to such a configuration, since the position of the employee Qa can be fixed until the employee Qa shifts to the moving state, the position detection of the employee Qa can be stopped during that period. Therefore, the load associated with the position detection of the employee Qa is reduced. Furthermore, the movement line of the employee Qa generated by the movement line creation module 662 is simplified and becomes easier to analyze. Note that the position detection module 661 may resume position detection after the employee Qa switches from the stopped state to the moving state.

[0077] Furthermore, the position detection module 661 can also use the above-described position fixing for automatic check-in and automatic check-out to the work seat D. That is, when check-in / check-out procedures are required for the use of the work seat D, it is possible to determine that the position of the employee Qa is fixed to a predetermined work seat D and at the same time check-in has been performed. Also, it is possible to determine that check-out has been performed at the same time as the state of the employee Qa switches from the stopped state to the moving state. According to such a configuration, since the employee Qa does not need to perform check-in / check-out procedures, the complexity of use is reduced and forgetting to perform the procedures can also be prevented. Therefore, the convenience and reliability of the system are improved.

[0078] The position of the beacon transmitter 3a detected as described above is stored in the memory 64.

[0079] The movement line creation module 662 calculates the movement line of the employee Qa based on the position of the employee Qa at each time detected by the position detection module 661. Specifically, the movement line creation module 662 creates the movement line of the employee Qa by connecting the positions of the beacon transmitters 3a at each time temporarily stored in the memory 64 in time series. The created movement line of the employee Qa is stored in the memory 64. The movement line of the employee Qa is used to construct the movement line database of the employee Qa. Such a movement line database can be used for optimizing the office layout.

[0080] The application device 6 has been described above. However, the configuration of the application device is not particularly limited as long as it can detect the position of the beacon transmitter 3 based on the intensity 73 of the beacon signal 31 and the inertial information 312. Therefore, for example, the Kalman filter correction may be omitted, and the observation position obtained in the previous stage may be determined as the position of the beacon transmitter 3. Also, it may not be necessary to detect the state (stopped state / moving state) of the employee Q.

[0081] The above has described the position detection system 1. As described above, such a position detection system 1 includes a beacon transmitter 3 that moves together with the employee Q to be tracked and transmits a beacon signal 31, a cluster-type network CN, and an application device 6 that communicates with the beacon transmitter 3 via the cluster-type network CN. Further, the beacon transmitter 3 is provided with an inertial sensor 33, and puts the inertial information 312 acquired by the inertial sensor 33 into the beacon signal 31 and transmits it. The cluster-type network CN includes a reception layer L1 provided with a tertiary communication device 5c as a plurality of receivers that receive the beacon signal 31, measure the intensity 73 of the received beacon signal 31, and transmit report data 7 including the intensity 73 and the inertial information 312, and a relay layer L2 provided with primary and secondary communication devices 5a and 5b that are relays for receiving the report data 7 transmitted by the tertiary communication device 5c and transmitting it to the application device 6. Then, the application device 6 detects the position of the employee Q based on the intensity 73 and the inertial information 312 included in the report data 7 acquired via the relay layer L2. In this way, by detecting the position of the employee Q using the inertial information 312 in addition to the intensity 73 of the beacon signal 31, the position detection accuracy of the employee Q is improved compared to the case of detecting the position of the employee Q using only the intensity 73 of the beacon signal 31.

[0082] Also, as described above, the inertial sensor 33 detects the angular velocity around the X-axis, Y-axis, and Z-axis, which are three mutually orthogonal axes, and the acceleration in the X-axis, Y-axis, and Z-axis directions. According to such a configuration, the translational motion (straight-line movement) of the employee Q can be detected based on the acceleration signals of the three orthogonal axes, and the rotational motion (direction change) of the employee Q can be detected based on the angular velocity signals of the three orthogonal axes. Then, the operation of the employee Q can be detected based on the detected translational motion and rotational motion. Therefore, the movement of the employee Q can be detected more accurately.

[0083] Also, as described above, the inertial information 312 includes information regarding the amount of movement of the beacon transmitter 3 and information regarding the state of the worker Q. According to such a configuration, the movement of the worker Q can be detected more accurately using the amount of movement of the beacon transmitter 3 and the state of the worker Q.

[0084] Also, as described above, the tracking target is the worker Q as a person. Also, the state of the worker Q has a stopped state in which the worker Q is stopped and a moving state in which the worker Q is moving. According to such a configuration, by varying the detection method between the stopped state and the moving state, the position of the worker Q can be detected accurately in each state.

[0085] Also, as described above, the application device 6 detects the provisional position of the worker Q based on the intensity 73, calculates the observation position by correcting the provisional position based on the inertial information 312, and detects the position of the worker Q by performing Kalman filter correction using the observation position. According to such a configuration, the position of the worker Q can be detected accurately.

[0086] Also, as described above, the value of the Kalman gain included in the Kalman filter is varied between the stopped state and the moving state. According to such a configuration, the position of the worker Q can be detected accurately in each state.

[0087] Also, as described above, when in the stopped state, the position of the worker Q is fixed and the position detection of the worker Q is stopped, and the position detection of the worker Q is resumed after switching from the stopped state to the moving state. According to such a configuration, since the position of the worker Qa can be fixed until the worker Qa transitions to the moving state, the load associated with the position detection of the worker Qa is reduced.

[0088] Also, as described above, the tertiary communication device 5c is regularly arranged at regular intervals in the office, which is the position detection area for detecting the position of the employee Q. According to such a configuration, the tertiary communication devices 5c are evenly arranged throughout the office, and the beacon signal 31 can be received more reliably from any position within the office.

[0089] As described above, the position detection system of the present invention has been described based on the illustrated embodiments. However, the position detection system of the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration or any step having the same function. Also, any other arbitrary components or arbitrary steps may be added to the present invention.

Explanation of Reference Numerals

[0090] 1... Position detection system 3... Beacon transmitter 3a... Beacon transmitter 31... Beacon signal 311... Identification information 312... Inertial information 32... BLE communication unit 33... Inertial sensor 34... State detection unit 5... Communication device 5a... Primary communication device 5b... Secondary communication device 5c... Tertiary communication device 5cA... Tertiary communication device 5cB... Tertiary communication device 5cC... Tertiary communication device 51... Processor 53... BLE communication unit 54... Memory 6... Application device 61... Processor 63... BLE communication unit 64... Memory 661... Position detection module 662... Route creation module 7... Report data 71... Identification information 72... Installation location information 73... Intensity 74... Reception time CN... Cluster-type network D... Workstation D1... Domain D2... Domain D3... Domain D4... Domain L1... Reception layer L2... Relay layer P... Two-dimensional coordinates Pa... Two-dimensional coordinates Pb... Two-dimensional coordinates Pc... Two-dimensional coordinates Q... Employee Qa... Employee Ra... Distance Rb... Distance Rc... Distance

Claims

1. A beacon transmitter that moves with a target to be tracked and transmits a beacon signal, A cluster-type network, An application device that communicates with the beacon transmitter via the cluster-type network, and has, The beacon transmitter includes an inertial sensor, and inserts inertial information acquired by the inertial sensor into the beacon signal and transmits it, The cluster-type network includes a receiving layer including a plurality of receivers that receive the beacon signal, measure the intensity of the received beacon signal, and transmit report data including the intensity and the inertial information, and a relay layer including a repeater that receives the report data transmitted by the receiver and transmits it to the application device, The application device detects the position of the tracking target based on the intensity and the inertial information included in the report data acquired via the relay layer. A position detection system characterized by this.

2. The position detection system according to claim 1, wherein the inertial sensor detects angular velocities around three axes orthogonal to each other and accelerations in the three-axis directions.

3. The position detection system according to claim 1, wherein the inertial information includes information regarding the amount of movement of the beacon transmitter and information regarding the state of the tracking target.

4. The tracking target is a person, The position detection system according to claim 3, wherein the state of the tracking target includes a stopped state in which the tracking target is stopped and a moving state in which the tracking target is moving.

5. The application device detects a provisional position of the tracking target based on the intensity, calculates an observed position by correcting the provisional position based on the inertial information, and detects the position of the tracking target by Kalman filter correction using the observed position. The position detection system according to claim 4.

6. The position detection system according to claim 5, wherein the value of the Kalman gain included in the Kalman filter is made different between the stopped state and the moving state.

7. The position detection system according to claim 4, wherein when in the stopped state, the position of the tracking target is fixed and the position detection of the tracking target is stopped, and after switching from the stopped state to the moving state, the position detection of the tracking target is restarted.

8. The position detection system according to claim 1, wherein the receivers are regularly arranged at regular intervals in a position detection area for detecting the position of the object to be tracked.

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