JP2023132585A - Device to be positioned, reference device, positioning system, management device, positioning method, and program - Google Patents

Abstract

To provide a positioning system capable of performing mixedly a position identification mode for positioning at low cost the current position of the device to be positioned that is located in a narrow space such as a private room, and a position identification mode for positioning highly accurately the current position of the device to be positioned, without changing the configuration or operation of a reference device used for positioning.SOLUTION: A plurality of reference devices transmit, to a management device via a communication network, information concerning reception results of positioning signals transmitted from a device to be positioned. When a first position identification mode is set, in which a current position of the device to be positioned is identified simply, the management device identifies, as the current position of the device to be positioned, a position close to a reference device having a high reception intensity included in the positioning signal reception result among a plurality of reference devices. When a second position identification mode is set, in which the current position of the device to be positioned is identified with high accuracy, the management device calculates, to identify, the current position of the device to be positioned, on the basis of the positioning signal reception results of the plurality of reference devices.SELECTED DRAWING: Figure 1

Description

The present invention relates to a positioning target device, a reference device, a positioning system, a management device, a positioning method, and a program.

Conventionally, in areas such as indoors where radio waves from GNSS satellites are difficult to reach, the positioning target device (hereinafter also referred to as "target device") is connected to multiple reference devices installed at known position coordinates. There are known positioning systems that transmit and receive wireless media such as radio waves, sound waves, and light in a line-of-sight environment (LOS environment) between (See Reference 1).

International Publication No. 2018/155437

In the conventional system that utilizes the transmission and reception of wireless media such as radio waves in the above-mentioned line-of-sight environment (LOS environment), the positioning target can be positioned in a narrow space such as a private room without changing the configuration or operation of the reference device used for positioning. There is a problem in that it is desired to implement a position specifying mode that can measure the current position of a device at a low cost and a position specifying mode that can measure the current position of a device to be positioned with high precision in a mixed manner.

A positioning system according to one aspect of the present invention includes a device to be positioned, a plurality of reference devices installed at mutually different known position coordinates, and a management device capable of communicating with the plurality of reference devices via a communication network. This is a positioning system equipped with . The positioning target device includes a transmitter that transmits a positioning signal using a wireless medium. Each of the plurality of reference devices includes a receiving unit that receives the positioning signal transmitted from the positioning target device, and a transmitting unit that transmits information on the reception result of the positioning signal to the management device via the communication network. and has. The management device includes a storage unit that stores management information for managing a setting status of a position specifying mode set in the plurality of reference devices, and a storage unit that receives the positioning signal from the plurality of reference devices via the communication network. A receiving unit that receives result information and a first position specifying mode that simply specifies the current position of the positioning target device are set, the reception result of the positioning signal from among the plurality of reference devices A second position specifying mode is set in which a position close to a reference device with a high reception strength included in the positioning target device is specified as the current position of the positioning target device, and the current position of the positioning target device is determined with high precision. In this case, the device further includes a position specifying unit that calculates and specifies the current position of the positioning target device based on the reception results of the positioning signals of the plurality of reference devices.

A device according to another aspect of the present invention is a positioning target device provided in the positioning system. The positioning target device may be a moving body whose position coordinates change.

A device according to still another aspect of the present invention is any one of a plurality of reference devices included in the positioning system.

A device according to still another aspect of the present invention is a management device provided in the positioning system and capable of communicating with the plurality of reference devices via a communication network.

A method according to yet another aspect of the present invention is a method of positioning a positioning target device. In this method, the positioning target device transmits a positioning signal using a wireless medium, and a plurality of reference devices installed at mutually different known position coordinates each transmit the positioning signal transmitted from the positioning target device. receiving the signal and transmitting information on the reception result of the positioning signal to a management device via a communication network, and the management device managing the setting status of the positioning mode set in the plurality of reference devices. the management device stores information on the reception results of the positioning signals from the plurality of reference devices via the communication network; When the first position specifying mode for simply specifying the current position of the reference device is set, the position nearer to the reference device with the highest reception strength included in the reception result of the positioning signal among the plurality of reference devices is set. When a second position specifying mode is set in which the current position of the target device is determined and the current position of the positioning target device is determined with high precision, the reception results of the positioning signals of the plurality of reference devices are calculating and specifying the current position of the positioning target device based on the location information.

A program according to still another aspect of the present invention is a program executed on a computer or processor included in the management device. This program includes a program code for storing management information for managing the setting status of the positioning mode set in the plurality of reference devices, and a program code for storing management information for managing the setting status of the positioning mode set in the plurality of reference devices, and a program code for storing the management information for managing the setting status of the positioning mode set in the plurality of reference devices, and a program code for storing the management information for managing the setting status of the positioning mode set in the plurality of reference devices, and a program code for storing the management information for managing the setting status of the positioning mode set in the plurality of reference devices. When a program code for receiving reception result information and a first position specifying mode for simply specifying the current position of the positioning target device are set, the positioning signal from among the plurality of reference devices is set. A second position specifying mode is set in which a position close to a reference device with a high reception strength included in the reception result is specified as the current position of the positioning target device, and the current position of the positioning target device is determined with high precision. If the positioning target device is located, the method further includes a program code for calculating and specifying the current position of the positioning target device based on the reception results of the positioning signals of the plurality of reference devices.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, when only one of the plurality of reference devices receives the positioning signal in the first position specifying mode. , a position close to the installation position of the one reference device may be specified as the current position of the positioning target device.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, in the first position specifying mode, two or more reference devices among the plurality of reference devices receive the positioning signal. When the positioning signal is received, a position near the installation position of the reference device where the reception strength of the positioning signal is the highest may be specified as the current position of the positioning target device.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, each of the plurality of reference devices may be installed in a plurality of private rooms, or may be installed on a wall, a threshold, or a wall in the same area. They may be installed in a plurality of individual open spaces separated by screens or partitions, or they may be installed in a plurality of individual open spaces that are separated to the extent that positioning signals from the wireless medium do not reach each other in a line-of-sight environment within the same area. It may be installed in space.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, the plurality of reference devices may be managed for mutual time synchronization or time difference, and in the second position specifying mode. , the current position of the positioning target device may be calculated based on the reception result of the positioning signal received from each of the plurality of reference devices and information on the position coordinates of each of the plurality of reference devices. . Here, in the second position specifying mode, information on the time difference between the plurality of reference devices is acquired, and the information on the time difference, the reception result of the positioning signal, and the position of each of the plurality of reference devices are obtained. The current position of the positioning target device may be calculated based on the coordinate information.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, the wireless medium may be UWB (ultra wideband) radio waves.

In the positioning target device, the positioning system, the management device, the positioning method, and the program, the positioning target device may be a wireless IC tag.

Furthermore, in the positioning target device, the positioning system, the management device, the positioning method, and the program, the position of the positioning target device may be estimated using a learned model of machine learning.

According to the present invention, a positioning mode and a positioning mode that can determine the current position of a positioning target device located in a small space such as a private room at low cost without changing the configuration or operation of a reference device used for positioning and It is possible to implement a combination of position specifying modes that measure the current position of the device with high precision.

FIG. 1 is an explanatory diagram showing an example of the main configuration of a positioning system according to an embodiment. FIG. 2 is a block diagram showing an example of the main configurations of a reference device, a target device, and a management device of a positioning system according to an embodiment. FIG. 2 is an explanatory diagram showing an application example in which reference devices (anchors) of the positioning system according to the embodiment are arranged in each room of a building. FIG. 2 is an explanatory diagram showing an application example in which a reference device (anchor) of the positioning system according to the embodiment is arranged along a production line in a factory.

Embodiments of the present invention will be described below with reference to the drawings.
The positioning system according to the embodiment described in this document operates in a line-of-sight environment (LOS environment) between a tag (a device to be positioned) and a plurality of anchors (reference devices) installed at mutually different known position coordinates. ), which transmits and receives positioning signals using ultra-wideband (UWB) radio waves, and uses the results of the transmission and reception as input to determine the current location of the tag (device to be positioned), which can provide indoor positioning services using UWB. It is a system. In particular, the side system of this embodiment has a first positioning mode (UWB 1-point positioning mode) that simply pinpoints the current position of the tag, and a second positioning mode that positions the tag's current position with high precision. This is a positioning system that can be implemented in a mixture of modes. The first positioning mode (UWB 1-point positioning mode) uses a low-cost configuration in which one anchor (reference device) is installed in each relatively small room such as a nursing home or hospital room. It is possible to detect when a tag enters a room and determine the location of the tag. In the latter second positioning mode, for example, the position coordinates of the tag are calculated using an algorithm of the TDoA (Time Difference of Arrival) method or the ToA (Time of Arrival) ranging estimation method based on the transmission and reception of the positioning signal. Identify.

The TDoA positioning system of this embodiment is suitable for positioning the position coordinates of a tag in an area such as an indoor area where radio waves from a GNSS satellite cannot reach or are difficult to reach. The positioning system of this embodiment is suitable for realizing a real-time positioning system (RTLS) that measures the position of a positioning target device such as a tag in real time.

In particular, the positioning system of this embodiment can be applied to objects such as clothes and bags of people who move in indoor areas such as hospitals, nursing homes, and factories, helmets and hats of workers, products under manufacture, forklifts, robots, and drones. This is a positioning system that makes it possible to identify in real time the current position of a device (tag, edge device, UWB device) to be positioned that is mounted on a mobile body.

FIG. 1 is an explanatory diagram showing an example of the main configuration of a positioning system according to an embodiment of the present invention. In the positioning system shown in Fig. 1, one unit is installed in each of relatively narrow target spaces 10A (1) to 10A (3) partitioned by walls on the right side of the figure, and the first positioning system (hereinafter referred to as “1 A plurality of reference devices (hereinafter also referred to as "anchors") 20A (1) to 20A (3) used in "point positioning mode" or "UWB single point positioning mode") and A plurality of reference devices 20B (1) installed at mutually different known position coordinates and used in the second and first position specifying modes (hereinafter also referred to as "multi-point positioning mode" or "4-point positioning mode"). 20B(4). The one-point positioning mode is a positioning mode in which the current position of the device 30A to be positioned (hereinafter also referred to as "target device") is simply specified. The multi-point positioning mode is a positioning mode in which the current position of the target device 30B is determined with high precision. The positioning system may further include positioning target devices 30A and 30B.

The example in FIG. 1 shows a positioning system that uses the TDoA method to measure the position of the target device 30 in the multiple-point positioning mode in the target space 10 on the left side of the figure. The position of the target device 30 may be determined using other positioning methods.

Furthermore, in the example of FIG. 1, the number of reference devices 20B(1) to 20B(4) in the target space 10B in the multi-point positioning mode is four, but even if the number of reference devices in the target space is five or more, good. In addition, the number of target devices 30A and 30B in the target spaces 10A(1) to 10A(3) and 10B in each positioning mode is 1, but the number of target devices 30A and 30B in the target spaces 10A(1) to 10A(3) and 10B is 1. , 30B may be two or more.

In addition, in the example of FIG. 1, the case where the number of target spaces 10A(1) to 10A(3) in the one-point positioning mode is 3 is shown, but the number of target spaces in the one-point positioning mode is singular, 2 Or it may be 4 or more. In the example of FIG. 1, the number of target spaces 10B in the multi-point positioning mode is single, but the number of target spaces in the multi-point positioning mode may be 2, or 3 or more. There may be.

Note that when describing matters common to the plurality of target spaces 10A(1) to 10A(3), 10B in the positioning system of FIG. 1, they will be referred to as target space 10. Also, when explaining matters common to each of the reference devices 20A(1) to 20A(3) and 20B(1) to 20B(4), reference devices 20 or 20(1), 20(2), It is written as... Further, when describing matters common to each target device 30A, 30B, it will be described as target device 30.

Further, as shown in FIG. 1, the positioning system of this embodiment includes a management device 40 that can communicate with each of the plurality of reference devices 20(1) to 20(4). The management device 40 may be able to communicate with the target device 30.

In FIG. 1, each of the reference devices 20A(1) to 20A(3) set to the one-point positioning mode is installed in a private room of a nursing home, hospital, company, etc., for example. The reference devices 20A(1) to 20A(3) may be installed in individual open spaces partitioned by walls, thresholds, screens, or partitions within the same area, such as a production line in a factory, for example. The reference devices 20A(1) to 20A(3) may be installed on the surface of a structure such as a ceiling, a wall, a threshold, a screen, a partition, a support, or the like. In addition, the reference device used in the one-point positioning mode can be used in multiple individual open spaces (for example, in the center and end of a long hallway) that are separated to the extent that positioning signals via wireless media do not reach each other in a line-of-sight environment within the same area. It may be installed in a space).

The installation position of the reference device 20 in the one-point positioning mode can be managed using, for example, the room number of the private room in which the reference device is installed or the identification information of the individual open space.

Further, in FIG. 1, the reference devices 20 (1) to (4) in which the multi-point positioning mode is set are used for different two-dimensional or three-dimensional target spaces 10 inside a relatively large room such as a building. Installed in multiple locations. The installation positions of the plurality of reference devices 20(1) to (4) differ from each other in at least one of the horizontal position and height.

The number of reference devices 20 in the multi-point positioning mode is set, for example, according to the algorithm of the positioning method. For example, when positioning the target device 30 in a three-dimensional space using the TDoA method, the number of reference devices 20 is, for example, four or more. Note that when positioning the target device 30 in a two-dimensional area, the number of reference devices may be three or more.

For the plurality of reference devices 20 in the multi-point positioning mode, mutual time synchronization or time difference is managed by any synchronization method applicable between the devices. Each of the plurality of reference devices 20 includes an internal clock whose time synchronization or time difference between the reference devices 20 is managed.

Here, the above-mentioned "time synchronization" means synchronizing specific points in time between the plurality of reference devices 20, and may also be referred to as "time synchronization." Further, as an example of the case where the above-mentioned time synchronization is managed, for example, a common transmitting device is installed at a position where the positional relationship (for example, distance) with each of the plurality of reference devices 20 is known. The management device 40 measures the time difference between the time stamps of the reception timings at which the plurality of reference devices 20 received the signal transmitted from the transmitting device, and uses the time difference as an Offset value (clock deviation of the reference devices) between the reference devices. For example, it can be maintained. This Offset value between the reference devices is used to correct the reception time difference (time stamp difference) between the reference devices used to calculate the distance between the target device 30 and the plurality of reference devices 20 in TDoA positioning described later. It is possible to calculate (estimate) the current position of the target device 30 without performing time synchronization between the plurality of reference devices 20. Note that, after the initial setting, the Offset value is updated at a predetermined timing (for example, at a regular timing in a predetermined cycle) by measuring the time difference between the time stamps of the reception timings of the signals from the common transmitting device. You may.

The known positional coordinates where each of the plurality of reference devices 20 in the multi-point positioning mode are installed are, for example, relative positional coordinates in a coordinate system set in advance in the target space 10. The positional coordinates of the plurality of reference devices 20 in this embodiment may be relative positional coordinates in an orthogonal coordinate system in which the origin is set at an arbitrary point within the target space 10. For example, the position coordinates of the plurality of reference devices 20 may be relative position coordinates in an orthogonal coordinate system in which the origin is set at an arbitrary point on the vertical coordinate axis passing through the installation position of any one of the reference devices 20. good.

The position coordinates of the plurality of reference devices 20 in a predetermined coordinate system of the target space 10 are, for example, the position coordinates of the positioning signals between the reference device 20 and the plurality of auxiliary anchors (auxiliary reference devices) of the anchor installation base (installation auxiliary device). It may also be specified by sending and receiving.

The position coordinates of the plurality of reference devices 20 may be specified, for example, by performing a surveying operation using a general surveying technique (eg, a total station, a laser ranging sensor). In addition, if some or all of the plurality of reference devices 20 are placed in an area where radio waves from GNSS satellites can be received, the known position coordinates of some or all of the reference devices 20 may be used as the GNSS receiver. You may also use the position coordinates measured in . In this case, the position coordinates may be, for example, latitude, longitude, and altitude, or may be a coordinate position (X, Y, Z) in an ECEF (Earth-Centered Earth-Fixed) coordinate system in which a certain reference point is defined. There may be. Also, even if the coordinates are on a converted coordinate system converted to ENU (East (m), North (m), Upper Up (m): relative distance from the reference point) coordinates with a certain reference point as the origin, good.

The target device 30 is, for example, a wireless IC tag (hereinafter also referred to as "tag"). The target device 30 may be a tag, a self-propelled device such as a trolley, a forklift, a robot, or a drone, various parts, or various products. The target device 30 may be a moving device, a temporarily stopped device, or a fixedly located device.

The target device 30 transmits a positioning signal to each of the plurality of reference devices 20 using a predetermined wireless medium. The wireless medium used for transmitting and receiving positioning signals is a wireless medium such as radio waves, sound waves, and light. In this embodiment, UWB (ultra wideband) radio waves are used as the wireless medium. UWB is a communication technology using weak radio waves in a wide band (for example, a bandwidth of several hundred MHz centered on an arbitrary frequency in a several GHz band), and is defined by IEEE 802.15.4.

The management device 40 may be, for example, a cloud computer system (hereinafter also referred to as a "cloud system") built on an open communication network 45 such as the Internet, or a locally closed network such as an on-premises system. It may also be configured such that it is connected to. The management device 40 may be a server composed of a single computer device or a plurality of computer devices. Communication between the management device 40 and the plurality of reference devices 20 can be performed via a communication network 45 including, for example, a mobile communication network (for example, LTE, 5G), a wireless local network (for example, Wi-Fi), etc. can. This communication can be performed, for example, via a wired or wireless communication line. The communication line may be a public line or a private line.

FIG. 2 is a block diagram showing an example of the main configurations of the reference device (anchor) 20, target device (tag) 30, and management device 40 of the positioning system of this embodiment. In FIG. 2, the reference device 20 includes a UWB communication section 210, a storage section 230, and a NW communication section 240. The reference device 20 may include a USB power supply function and a USB data output function.

The UWB communication unit 210 also functions as a receiving unit for positioning signals during positioning of the target device 30. The UWB communication unit 210 is composed of, for example, a UWB wireless communication module. The UWB communication unit 210 receives, via the antenna 211, a positioning signal transmitted (broadcast) from the target device 30 using UWB radio waves when positioning the target device 30.

Further, the UWB communication unit 210 outputs information included in the positioning signal received from the target device 30 and reception time information (Timestamp) of the positioning signal.

The transmission format of the positioning signal transmitted from the target device 30 includes, for example, frame control information (Frame Control), transmission sequence number (Sequence Number), target device identification information (TAG ID) that can identify the target device 30, and message identification. information (Message ID), positioning management identification information (Purpose ID), and data error recovery information (CRC). The positioning management identification information (Purpose ID) is, for example, information that can identify at least one of the purpose of positioning, the use of the positioning results, and the entity using the positioning results.

The storage unit 230 stores various information included in the positioning signal output from the UWB communication unit 210 and positioning signal reception time information (Timestamp), which is information on the transmission/reception result of the positioning signal, in association with each other. Furthermore, the storage unit 230 may store information on the position coordinates of the reference device (self-device) 20 and information on the time difference between it and other reference devices (for example, the aforementioned Offset value).

The NW communication unit 240 can communicate with the management device 40 via a wired or wireless communication line of the communication network 45. The NW communication unit 240 also has a function as a transmitting unit that transmits information on the reception result of the positioning signal received from the target device 30 to the management device 40.

The transmission format of the information on the reception result of the positioning signal transmitted to the management device 40 is, for example, target device identification information (TAG ID), reference device identification information (Anchor ID) that can identify the reference device (own device) 20, Target device count information (TAG Counter), positioning management identification information (Purpose ID), reception time information (Timestamp) of the positioning signal from the target device 30, radio field strength and absolute time information (Epoch Time), radio field strength and data error recovery information (CRC). The radio field strength is the strength of a received radio wave (for example, an RSSI (Received Signal Strength Indicator) value) for receiving a positioning signal from the target device 30. The transmission format of the information on the reception result may include information on the position coordinates of the reference device (self-device) 20 and information on the time difference with other reference devices (for example, the aforementioned Offset value).

In FIG. 2, the target device 30 includes a UWB communication section 310 and a storage section 330. Similar to the reference device 20, the target device 30 may have a USB power supply function and a USB data output function.

The UWB communication unit 310 is configured with, for example, a UWB wireless communication module, and transmits (broadcast transmission) a positioning signal having a transmission format including the above-mentioned positioning management identification information (Purpose ID) using UWB radio waves via the antenna 311. ) also functions as a transmitter. The positioning signal is, for example, a pulse-like signal, and is periodically transmitted at predetermined time intervals.

The storage unit 330 stores information to be included in the positioning signal transmitted from the UWB communication unit 310. Furthermore, the storage unit 330 may store positioning management identification information (Purpose ID) that is preset in the reference device 20.

In FIG. 2, the reference device 20 to which the multi-point positioning mode has been set determines the position coordinates (or the distance between each reference device) of the plurality of reference devices 20 in the target space at an arbitrary timing prior to positioning the target device 30. information can be downloaded from the management device 40 as an anchor coordinate file, and information on the time difference between the reference devices (Offset value) can be downloaded from the management device 40 as an offset table file at any timing. Further, the reference device 20 may access and inquire about the management device 40 periodically (for example, at intervals of several seconds) to continuously update the anchor coordinate file and the offset table file.

In FIG. 2, the management device 40 includes a NW communication section 410, a position specifying section (positioning calculation section) 420, and a storage section (DB) 430. The NW communication unit 410 also functions as a receiving unit that receives information on the transmission and reception results of positioning signals during positioning of the target device 30.

The NW communication unit 410 can communicate with the plurality of reference devices 20 and target devices 30 via a wired or wireless communication line of the communication network 45. The NW communication unit 410 also functions as a transmitting unit that transmits information on the position coordinates of the plurality of reference devices 20 and information on the time difference between the reference devices (for example, the aforementioned Offset value) to the plurality of reference devices 20. do.

The NW communication unit 410 receives positioning-related information regarding the positioning of the target device 30 from each reference device 20 when positioning the target device 30 . The positioning related information from the reference device 20 includes, for example, target device identification information (TAG ID), reference device identification information (Anchor ID) that can identify the reference device (own device) 20, target device count information (TAG Counter), It includes positioning management identification information (Purpose ID), positioning signal reception time information (Timestamp) from the target device 30, radio field strength, and absolute time information (Epoch Time).

The position specifying unit 420 has a function of specifying the position of the target device 30 during positioning of the target device 30. The positioning calculation unit 420 identifies (positions) the current position of the target device 30 for each target device 30, for example, based on the positioning-related information received from each reference device 20.

For example, in the one-point positioning mode, when there is only one reference device 20 that has received a positioning signal from the target device 30, the position specifying unit 420 locates the location near the installation position of the reference device 20 (where the reference device 20 is located). The room or individual open space in which the target device 30 is located is specified as the current location of the target device 30.

In the one-point positioning mode, the position specifying unit 420 determines the current position of the target device 30 for each positioning management identification information (Purpose ID) and for each target device 30 based on the positioning related information received from the reference device 20. may be specified.

For example, in the one-point positioning mode, if there are a plurality of reference devices 20 (two or three or more) that have received the positioning signal from the target device 30, the position specifying unit 420 may detect the location of the positioning signal among the plurality of reference devices 20. A position near the installation position of the reference device 20 (the room or individual open space where the reference device 20 is placed) where the reception intensity (radio wave intensity) is the highest is specified as the current position of the target device 30.

Furthermore, in the multi-point positioning mode, the position specifying unit 420 performs a positioning calculation for calculating and specifying (positioning) the current position of the target device 30 based on the positioning-related information received from the plurality of reference devices 20 in the target space 10. function as a department. Here, the position specifying unit (positioning calculation unit) 420 identifies the target device 30 for each positioning management identification information (Purpose ID) and for each target device 30 based on the positioning related information received from each reference device 20. The current position may be calculated and specified (positioned). Information on the time difference between the reference devices (for example, the aforementioned Offset value) may also be used to calculate this current position.

A storage unit (DB) 430 stores positioning-related information used for calculations in the position specifying unit (positioning calculation unit) 420 and information calculated by the positioning calculation unit 420 for each positioning management identification information (Purpose ID) and for each target device 30. Store the positioning results (location results). Note that the anchor information DB of the storage unit (DB) 430 may store information on the time difference between the reference devices used in the multi-point positioning mode (for example, the aforementioned Offset value). Further, the anchor information DB of the storage unit (DB) 430 may store positioning management identification information (Purpose ID) set in advance for each of the plurality of reference devices 20.

For example, the storage unit (DB) 430 includes a DB (anchor information DB) that manages information on the reference device 20 and information on the reception results of the reference device 20 so as to correspond to the one-point positioning mode and the multiple-point positioning mode. It has a DB (log DB) to manage, and a DB (positioning result DB) to manage information on the positioning result (positioning result) of the target device 30.

Table 1 shows an example of anchor management information in the anchor information DB.

In the example of Table 1, for each of the plurality of reference devices (anchors) 20, the company ID that identifies the installation entity or management entity, the reference device identification information (Anchor ID), the positioning management identification information (Purpose ID), and the reference device ( Identification information of the positioning mode (1-point positioning, 4-point positioning) set in the anchor) 20, information on the position coordinates (relative coordinates) of the installation position of the reference device (anchor) 20, and related information are stored in association with each other. has been done. The related information is identification information (room number) of the room in which the reference device (anchor) 20 in which the one-point positioning mode is set is installed.

When positioning (positioning) is performed in the one-point positioning mode, "1" is set in the one-point positioning flag as identification information of the positioning mode in the anchor management information of the relevant reference device (anchor). As a result, positioning from three or four or more reference devices (anchors) is normally required, but if TagInfo information is being received by one anchor at the timing when the one-point positioning flag is set, This displays the one-point positioning result and the strength of the received radio waves (RSSI value) of the target device (tag) on the display unit of the management device 40 using front-end visualization. If multiple reference devices (anchors) in single-point positioning mode receive the same target device (tag), priority is given to the reference device (anchor) with the higher received radio wave strength (RSSI value). Ru. A reference device (anchor) whose 1-point positioning flag is set to something other than "1" is a target device (tag) using the normal multi-point positioning mode (4-point positioning in the case of 3D, 3-point positioning in the case of 2D). positioning is performed.

Table 2 shows an example of information on tag positioning results in the positioning result DB.

In the example of Table 2, for each positioning of the target device (tag) 30, the reception time information (Timestamp) of the positioning signal from the target device 30, the target device identification information (TAG ID), and the positioning management identification information (Purpose ID). , identification information of the positioning mode (1-point positioning, 4-point positioning), the number of reference devices (anchors) 20 used for positioning, information on the position coordinates (relative coordinates) of the positioning result of the positioning target (tag) 30, Identification information of the reference device (anchor) 20 with the highest received radio wave intensity (for example, RSSI value) among the plurality of reference devices (anchors) 20 used, and DoP (Dilution Of) as measurement quality information indicating the rate of decrease in positioning accuracy. Precision) value, positioning calculation status (positioning OK, not calculated), and received radio wave strength (RSSI value) are stored in association with each other.

In real-time display of the positioning results that are the positioning results of the target device (tag) 30, the target device identification information (TAG ID) corresponding to the target device (tag) 30 is displayed not only in the 4-point positioning mode and the 1-point positioning mode. The name (anchor name) of the reference device (anchor) 20 with the highest radio wave intensity (RSSI value) is recorded. In the case of one-point positioning mode, the anchor name and position are managed as the position of the target device (tag) 30.

FIG. 3 is an explanatory diagram showing an application example in which the reference device (anchor) 20 of the positioning system according to the present embodiment is arranged in each room of a building. In the example of FIG. 3, there are a plurality of rooms (private rooms and hospital rooms) 10(1) to 10(20) partitioned by walls 11 in a building 100 such as a nursing home or hospital, and individual open spaces 10(20) separated from each other in a hallway. 21) to 10 (24), reference devices (anchors) 20 indicated by ■ in the figure are arranged, one for each room. ▲ in the figure is the target device (tag) 30 to be searched. The management device 40 detects that the target device (tag) 30 has entered the room 10 (4) based on the information of the reception result of the reference device (anchor) 20 installed in the room 10 (4). be able to. The management device 40 does not perform positioning to calculate the position coordinates of the target device (tag) 30, but rather determines the room 10 (4) in which the reference device (anchor) 20 that has received radio waves from the target device (tag) 30 is installed. The current location of the target device (tag) 30 is highlighted using a specific color, hatching, or the like. In this example, the location of the target device (tag) 30 can be determined by reception by one reference device (anchor) in each room using the one-point positioning mode. In this example, the wall 11 that partitions the room allows radio waves to pass through to some extent depending on its material, so the transmission power of the radio waves emitted by the target device (tag) 30 can identify the location of the target device (tag) 30. It may be set to be weaker within the range, or it may be filtered by the transmission strength of the target device (tag) 30.

FIG. 4 is an explanatory diagram showing an application example in which the reference device (anchor) 20 of the positioning system according to the present embodiment is arranged along a production line in a factory. In the example of FIG. 4, a plurality of adjacent individual open spaces 13(1), 13(2) separated from each other by thresholds 14 are set along the production line 12 of the factory, and the individual open spaces 13(1), 13(2), reference devices (anchors) 20(1) and 20(2) are arranged respectively. In this example, in the one-point positioning mode, target devices (tags) 30, 31 determine which area of the manufacturing line 12 is detected by reception by the reference devices (anchors) 20(1), 20(2) placed along the manufacturing line 12. You can see if the products marked with ' are being moved.

Note that the TDoA method that can be used in the multi-point positioning mode of the positioning system of this embodiment can be performed, for example, as follows. In the TDoA method, the dynamically changing time difference (Offset value), which is the time difference (clock difference) between the target device 30 and the plurality of reference devices 20 held in the management device 40, is, for example, as follows. This can be specified by synchronization/calibration processing such as: Here, static data of the positional coordinates (for example, X, Y, Z in an orthogonal coordinate system) of the installation locations of the plurality of reference devices 20 is measured in advance and held in the management device 40. The management device 40 synchronizes each reference device (Anchor Sync) with a command to check for time stamp discrepancies, and collects the timestamps of the reference device 20(0) as an initiator and the reference device 20(n) as another responder. For example, when the management device 40 instructs the reference device 20(0) to perform synchronization/calibration processing with another reference device 20(n), the reference device 20(0) attaches the outgoing Timestamp (Tx0ts) and transmits the UWB Transmits (transmits) a synchronization signal using radio waves. When the other reference device 20(n) receives the synchronization signal, it knows the outgoing Timestamp (Tx0ts) from the reference device 20(0) and its own received Timestamp (Rxnts). send to Transmission time information (Timestamp: Tx0ts) of this reference device 20 (0) and reception time information (Timestamp: Rxnts) of other reference devices 20 (n) are sent to the management device 40. The difference between Tx0ts and Rxnts is the sum of the clock offset (TS_Offset) between the reference device 20(0) and other reference devices 20(n) and the time of flight (ToF) during which the radio waves travel the distance between the reference devices. be.

Furthermore, the management device 40 collects ToF values corresponding to the distance between the reference devices using a calibration command. This ToF value is the distance between the reference devices (for example, the distance between the reference device 20(0) and another reference device 20(n)) measured by the ToF (Time of Flight) method that performs TWR (two-way ranging) between the reference devices. Distance Dis0n).

The management device 40 calculates information on the time difference between the reference devices (Offset value) based on the transmission time information (Timestamp) and reception time information (Timestamp) collected from each reference device and the distance between the reference devices. be able to. For example, the clock offset (TS_Offset) between the reference device 20(0) and the reference device 20(n) can be calculated as TS_Offset=Tx0ts-Rxnts-Dis0n/c (c: speed of light). Information on time differences (Offset values) between other reference devices can be calculated in the same way. Information on the time difference (Offset value) between these multiple reference devices is held in the management device 40 (and target device 30) as an Offset table.

Note that the distance between the reference devices used for calculating the time difference information (Offset value) may be calculated from the position coordinates of the installation location.

In the TDoA positioning system of each embodiment, the target device 30 and the management device 40 can calculate the current position of the target device 30, for example, using the following algorithm. Here, in the target space 10 of FIG. 1 described above, the positioning signal transmitted from the target device 30 reaches four reference devices 20 (1), 20 (2), 20 (3), and 20 (4). The reception times (Timestamps) are T1, T2, T3, T4, the propagation speed of the positioning signal is v [m/s], and the target device 30 and the reference device 20(1), 20(2), 20(3), 20(4) are D1, D2, D3, and D4, and the reception time difference of the positioning signal between the reference devices is ΔT12=T1-T2, ΔT13=T1-T3, ΔT14=T1-T4, ΔT23=T2 -T3, ΔT24=T2-T4, and ΔT34=T3-T4, the following relational expressions (1) to (6) hold true.

Distances D1, D2, D3, and D4, which are unknown variables, can be determined using the above relational expressions (1) to (6). These calculated distances D1, D2, D3, and D4 are the radii of four spherical surfaces whose origin is the known position coordinates of the reference devices 20(1), 20(2), 20(3), and 20(4). The current position of the target device 30 in the three-dimensional target space 10A can be calculated with an accuracy of several centimeters (for example, 3 to 10 cm) using any algorithm for determining the intersection point.

Note that when there is a time difference between the reference devices, ΔT12, ΔT13, ΔT14, ΔT23, ΔT24, and ΔT34 in the above relational expressions (1) to (6) are determined and held in advance by the above synchronization/calibration process. It is corrected using time difference information (Offset value).

As described above, according to the present embodiment, the current position of the target device (tag) 30 located in a narrow space such as a private room can be determined at low cost without changing the configuration or operation of the reference device (anchor) 20 used for positioning. A possible position specifying mode (one-point positioning mode) and a position specifying mode (multi-point positioning mode) for positioning the current position of the target device (tag) 30 with high precision can be implemented in a mixed manner.

In particular, according to the present embodiment, in the indoor positioning service using UWB, not only can highly accurate positioning be performed indoors, but also the approximate location of the target device (tag) 30, such as which private room, can be determined. It can be used for various purposes in UWB, and can meet the needs of people with disabilities.

In particular, according to the present embodiment, each reference device (anchor) has a positioning method (such as TDoA or If one reference device (anchor) can receive the transmission from the target device (tag), it is determined that the target device (tag) is near the reference device (anchor). The management device (RTLS) 40 can distinguish whether it is a reference device (anchor) or not. This notifies the management device (RTLS) 40 side that the reference device (anchor) has received the transmission from the target device (tag) without making any changes to the target device (tag) or reference device (anchor). In normal operation, the management device (RTLS) 40 assumes that the target device (tag) is near the installation position of the reference device (anchor) in one-point positioning mode, and changes the location of the reference device (anchor) to the target device (tag). It can be recognized as a certain position.

In particular, according to this embodiment, it is assumed that one reference device (anchor) is installed in each private room, and that the tag transmission is not received by the reference device (anchor) in another room. The reference device (anchor) that receives the transmission from the device (tag) notifies the radio wave reception strength from the target device (tag) as data sent to the RTLS side, so the management device (RTLS) 40 ), the evaluation can be performed using the reference device (anchor) that received the strongest radio waves as the closest reference device (anchor). Therefore, it is possible to correctly select in which private room the target device (tag) is located near the reference device (anchor).

In particular, according to the present embodiment, the indoor positioning method using UWB does not change the settings of the target device (tag) or reference device (anchor) that can perform highly accurate positioning such as TDoA or ToA. Without changing the mode, there is no problem even if it is mixed with high positioning accuracy, and it is possible to recognize that the target device (tag) is on the side of the reference device (anchor) in a small private room level. This makes it possible to use multiple positioning modes within a unified UWB positioning system without introducing other systems such as BLE or Wi-Fi. Furthermore, even if the transmission from the target device (tag) passes through the wall of the private room, the nearest reference device (anchor) can be selected based on the radio wave reception strength of the reference device (anchor).

Furthermore, since the present invention can provide the infrastructure for an indoor positioning system using UWB at a low cost, it can contribute to achieving Goal 9 of the Sustainable Development Goals (SDGs), "Create a foundation for industry and technological innovation." .

Note that the processing steps and components of the positioning system (eg, reference device, target device, management device) described herein can be implemented by various means. For example, these steps and components may be implemented in hardware, firmware, software, or a combination thereof.

Regarding hardware implementation, processing used to realize the above steps and components in an entity (e.g., various wireless communication devices, communication modules, Node B, Node G, terminal, hard disk drive device, or optical disk drive device) The unit or the like may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processors (DSPDs), programmable logic devices (PLDs), field programmable gates, etc. implemented in an array (FPGA), processor, controller, microcontroller, microprocessor, electronic device, other electronic unit designed to perform the functions described herein, computer, or combinations thereof; may be done.

Additionally, for firmware and/or software implementations, the means used to implement the components described above, such as processing units, may include programs (e.g., procedures, functions, modules, instructions) that perform the functions described herein. , etc.). In general, any computer/processor readable medium tangibly embodying firmware and/or software code, such as a processing unit, may be used to implement the above steps and components described herein. may be used for implementation. For example, the firmware and/or software code may be stored in memory and executed by a computer or processor, eg, in a controller. The memory may be implemented within the computer or processor, or external to the processor. The firmware and/or software code may also be stored in, for example, random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), electrically erasable PROM (EEPROM), etc. ), flash memory, floppy disks, compact disks (CDs), digital versatile disks (DVDs), magnetic or optical data storage devices, etc. good. The code may be executed by one or more computers or processors and may cause the computers or processors to perform certain aspects of the functionality described herein.

Further, the medium may be a non-temporary recording medium. Further, the code of the program may be read and executed by a computer, processor, or other device or apparatus, and its format is not limited to a specific format. For example, the code of the program may be a source code, an object code, or a binary code, or may be a mixture of two or more of these codes.

The description of the embodiments disclosed herein is also provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

10: Target space (target space)
20: Reference device 30: Target device (device targeted for positioning)
40: Management device 45: Communication network 210: UWB communication section 211: Antenna 230: Storage section 240: NW communication section 310: UWB communication section 311: Antenna 330: Storage section 410: NW communication section 420: Position specifying section (positioning calculation Department)
430: Storage section

Claims (16)

A positioning system comprising a positioning target device, a plurality of reference devices installed at mutually different known position coordinates, and a management device capable of communicating with the plurality of reference devices via a communication network,
The device to be positioned has a transmitter that transmits a positioning signal using a wireless medium,
Each of the plurality of reference devices includes:
comprising a receiving unit that receives the positioning signal transmitted from the positioning target device, and a transmitting unit that transmits information on the reception result of the positioning signal to the management device via the communication network,
The management device includes:
a storage unit that stores management information for managing the setting status of the positioning mode set in the plurality of reference devices;
a receiving unit that receives information on the reception results of the positioning signals from the plurality of reference devices via the communication network;
When a first position specifying mode for simply specifying the current position of the positioning target device is set, a reference device having a higher reception strength included in the reception result of the positioning signal among the plurality of reference devices is selected. When a second position specifying mode is set in which a nearby position is specified as the current position of the positioning target device and the current position of the positioning target device is determined with high precision, the positioning of the plurality of reference devices is performed. a position specifying unit that calculates and specifies the current position of the positioning target device based on the signal reception result;
A positioning system characterized by: The positioning system according to claim 1,
In the first position specifying mode, when only one reference device among the plurality of reference devices receives the positioning signal, the position specifying unit selects a position close to the installation position of the first reference device as the positioning target. A positioning system characterized by identifying the current position of a device. The positioning system according to claim 1,
In the first position specifying mode, when two or more reference devices among the plurality of reference devices receive the positioning signal, the position specifying unit selects a reference device having the highest reception strength of the positioning signal. A positioning system characterized in that a position close to an installation position is specified as the current position of the positioning target device. The positioning system according to any one of claims 1 to 3,
A positioning system characterized in that each of the plurality of reference devices is installed in a private room. The positioning system according to any one of claims 1 to 3,
A positioning system characterized in that each of the plurality of reference devices is installed in an individual open space partitioned by a wall, threshold, screen, or partition in the same area. The positioning system according to any one of claims 1 to 3,
A positioning system characterized in that each of the plurality of reference devices is installed in a plurality of individual open spaces separated to such an extent that positioning signals from the wireless medium in a line-of-sight environment within the same area do not reach each other. The positioning system according to any one of claims 1 to 6,
The plurality of reference devices have mutual time synchronization or time difference managed,
The position specifying unit of the management device, in the second position specifying mode, receives a reception result of the positioning signal received from each of the plurality of reference devices, and information on the position coordinates of each of the plurality of reference devices. A positioning system characterized in that the current position of the positioning target device is calculated based on the above. The positioning system according to claim 7,
The position specifying unit of the management device acquires information on a time difference between the plurality of reference devices in the second position specifying mode, and combines the information on the time difference, the reception result of the positioning signal, and the plurality of reference devices. A positioning system characterized in that the current position of the positioning target device is calculated based on information on the position coordinates of each of the reference devices. The positioning system according to any one of claims 1 to 8,
A positioning system characterized in that the wireless medium is UWB (ultra wideband) radio waves. The positioning system according to any one of claims 1 to 9,
A positioning system characterized in that the device to be positioned is a wireless IC tag. The positioning system according to any one of claims 1 to 10,
A positioning system characterized in that the device to be positioned is a moving body whose position coordinates change. The positioning target device constituting the positioning system according to any one of claims 1 to 11. The reference device constituting the positioning system according to any one of claims 1 to 11. The management device constituting the positioning system according to any one of claims 1 to 11. A method for positioning a positioning target device, the method comprising:
The positioning target device transmits a positioning signal using a wireless medium;
A plurality of reference devices installed at mutually different known position coordinates each receive the positioning signal transmitted from the positioning target device, and transmit information on the reception result of the positioning signal to the management device via a communication network. to send and
The management device stores management information for managing the setting status of the positioning mode set in the plurality of reference devices;
the management device receiving information on the reception results of the positioning signals from the plurality of reference devices via the communication network;
When the management device is set to a first location specifying mode in which the current location of the device to be positioned is simply specified, the reception strength included in the reception result of the positioning signal among the plurality of reference devices If a second position specifying mode is set, in which a position close to a reference device with a large Calculating and identifying the current position of the positioning target device based on the reception result of the positioning signal of the reference device;
A method comprising: A program executed on a computer or processor included in the management device according to claim 14,
a program code for storing management information for managing the setting status of the positioning mode set in the plurality of reference devices;
a program code for receiving information on the reception results of the positioning signals from the plurality of reference devices via the communication network;
When a first position specifying mode for simply specifying the current position of the positioning target device is set, a reference device having a higher reception strength included in the reception result of the positioning signal among the plurality of reference devices is selected. When a second position specifying mode is set in which a nearby position is specified as the current position of the positioning target device and the current position of the positioning target device is determined with high precision, the positioning of the plurality of reference devices is performed. a program code for calculating and identifying the current position of the positioning target device based on the signal reception result;
A program characterized by:

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