JP2023042094A - Location management system - Google Patents

Abstract

To provide a location management system that enables highly accurate location estimation even when holding a radio tag in the vicinity of a human body.SOLUTION: A location management system (1) of the present invention comprises: a plurality of transmission stations (10) that are installed in a room divided into a plurality of areas; a wireless tag (30) that receives radio signals the transmission stations (10) transmit; and a wireless tag reader (20) that collects the reception power strength of the radio signals in the wireless tag (30); and a location management device. The transmission station (10) is installed in a location where at least two transmission stations are in a state having a radio wave prospect to/from the wireless tag ensured, and the location management device is configured to estimate an area where the radio tag (30) exists based on the installment locations of the selected two transmission stations (10) based on the reception power strength in the radio tag (30), and a height at which the radio tag is held on a human body.SELECTED DRAWING: Figure 1

Description

The present invention relates to a position management system that estimates the position of a user in a building using wireless technology.

Conventionally, there have been proposed systems for locating a user's position in a building using wireless technology. In a positioning system using wireless technology, a slave unit held by a user receives wireless signals transmitted from multiple master units installed at fixed locations in a building, and the received power strength of the slave unit is used to By estimating the distance to the handset, the position of the handset moving in the building is estimated. In such a positioning system using wireless communication between a parent device and a child device, improving positioning accuracy is a common issue.

For example, in Patent Document 1, in a position detection system having a plurality of transmitting/receiving stations installed at predetermined positions and transmitting stations made up of passive tags, the transmitting stations transmit radio waves modulated with unique beacon signals. A position detection system has been proposed in which radio waves transmitted by a transmitting station are received by a plurality of transmitting/receiving stations and the position of the transmitting station is specified using the received power intensity of the received radio waves.

In addition, Patent Document 2 proposes a positioning system that includes a plurality of base units installed at fixed positions, a plurality of slave units composed of active tags that are mobile terminals, and passive tags installed at fixed positions. In the positioning system of Patent Document 2, in addition to signals transmitted from a plurality of master units installed at fixed positions, signals transmitted from slave units that have received signals from passive tags at fixed positions are used to determine slave units. Positioning systems have been proposed to estimate the position of

Japanese Unexamined Patent Application Publication No. 2002-236166 JP 2013-152133 A

Soichiro Morishita et al., "Person identification in moving images using UHF band RFID", Journal of Precision Engineering, Vol. 81, No. 6, 2015, p589-597

In the position detection system and the positioning system of Patent Documents 1 and 2, since a wireless tag is used as a child device, it is possible to realize highly accurate position estimation at a lower cost. If signals cannot be transmitted and received with three or more parent devices and child devices, there is a problem that the position estimation accuracy decreases. In particular, since the water permeability of radio waves in the frequency band used by wireless tags is low, when wireless tags are held near the human body, signals cannot be transmitted and received with three or more master units and slave units. , there is a problem that highly accurate position estimation cannot be performed (for example, see Non-Patent Document 1).

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position management system capable of highly accurate position estimation even when a wireless tag is held near the human body. aim.

In order to solve the above-described problems, in the location management system of the present invention, a plurality of mobile phones are installed at predetermined installation positions in a room divided into a plurality of areas and transmit first wireless signals containing unique identification information. a transmitting station; a wireless tag that receives the first wireless signal transmitted by the transmitting station and transmits a second wireless signal containing unique identification information; Using a wireless tag reader that collects the received power intensity of one wireless signal by receiving the second wireless signal, the information of the received power intensity in the wireless tag, and the installation position information of the transmitting station, a position management device for estimating an area in the room where the wireless tag exists, wherein the wireless tag is held close to the human body at a predetermined height of the human body of a user of the room; The transmitting stations are installed at positions where radio line-of-sight is ensured between at least two of the transmitting stations and the wireless tags, and the position management device controls the received power intensity of the wireless tags. estimating the area in the room in which the wireless tag exists, using information on the installation positions of the selected at least two transmitting stations and information on the height of the wireless tag held by the human body; .

According to the present invention, it is possible to provide a position management system that enables highly accurate position estimation even when a wireless tag is held near a human body.

FIG. 1 is a configuration example of a position management system according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining location management technology in the location management system according to the first embodiment of the present invention. FIG. 3 is a diagram for explaining the radio signal reception characteristics of the radio tag according to the first embodiment of the present invention. FIG. 4 is a diagram for explaining the radio signal reception characteristics of the radio tag according to the first embodiment of the present invention. FIG. 5 is a diagram for explaining installation positions of transmitting stations in the position management system according to the first embodiment of the present invention. FIG. 6 is a diagram for explaining the position estimation technique in the position management system according to the first embodiment of the present invention. FIG. 7 is a diagram for explaining the position estimation technique in the position management system according to the first embodiment of the present invention. FIG. 8 is a configuration example of a position management device according to the first embodiment of the present invention. FIG. 9 is an example of position management data of a transmitting station according to the first embodiment of the present invention. FIG. 10 is an example of position management data of wireless tags according to the first embodiment of the present invention. FIG. 11 is a diagram showing an example of an operation sequence of the location management system according to the first embodiment of the invention. FIG. 12 is a configuration example of a position management system according to the second embodiment of the present invention. FIG. 13 is a diagram for explaining the location management technique in the location management system according to the second embodiment of the present invention. FIG. 14 is an example of reference tag management data according to the second embodiment of the present invention. FIG. 15 is an example of location management data of wireless tags according to the second embodiment of the present invention. FIG. 16 is a diagram showing an example of an operation sequence of the position management system according to the second embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In addition, this invention is not limited to the following embodiment.

<First embodiment>
<Configuration of location management system>
FIG. 1 is a configuration example of a position management system according to the first embodiment of the present invention. The position management system 1 is installed at a predetermined position in a predetermined room BD in a building, and includes a plurality of transmitting stations 10 that transmit a radio signal (first radio signal) containing unique identification information, and the transmitting station 10. a wireless tag 30 that receives the transmitted wireless signal and transmits a wireless signal (second wireless signal) containing unique identification information; It comprises a wireless tag reader 20 that receives wireless signals, a position management device 100 that is connected to a plurality of transmitting stations 10 and the wireless tag reader 20 via a network NW, and that manages the position of the wireless tag 30 in a predetermined room BD in the building. The wireless tag 30 is held close to the human body at a predetermined height of the human body of the user 2 in the room BD.

In the configuration example of FIG. 1, four transmitting stations 10 and four wireless tag readers 20 are installed at predetermined positions in the room BD. At least two transmitting stations 10 are installed at positions where radio line-of-sight is ensured between them and the wireless tags 30 . The wireless tag 30 is given when the user 2 enters the room BD in the building, and is used to identify the position of the user 2 within the area. The wireless tag 30 receives the wireless signal transmitted by the transmitting station 10, the wireless tag reader 20 collects information on the received power intensity of the wireless tag 30, and the position management device 100 uses the collected received power intensity information. to estimate the position of the wireless tag 30 .

The location management device 100 is connected to a plurality of transmission stations 10 and wireless tag readers 20 via a network NW. Positions of a plurality of transmitting stations 10 and wireless tag readers 20 are registered in advance in the position management device 100 . The location management device 100 estimates the area where the wireless tag exists in the room BD using the information of the received power intensity of the wireless tag 30 and the installation location information of the transmitting station 10 .

<Location management in the location management system>
FIG. 2 is a diagram for explaining location management technology in the location management system according to the first embodiment of the present invention. In the position management system of this embodiment, the wireless tag 30 is held at a predetermined height of the human body of the user 2 in the room BD. The area in which the wireless tag 30 exists in the room BD is estimated using information on the installation positions of at least two transmitting stations 10 that are large and information on the height of the wireless tag 30 held by the human body. In the example of FIG. 2, the room BD is divided into 9 areas (CA#1 to CA#9). The area where the wireless tag 30 exists is estimated from CA#1 to CA#9).

<Reception characteristics of wireless tags>
3 and 4 are diagrams for explaining the radio signal reception characteristics of the radio tag according to the first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the orientation of the wireless tag 30 and the received power intensity. As shown in FIG. 2, it can be seen that the received power intensity fluctuates greatly according to the orientation of the wireless tag 30 . FIG. 4 is a diagram showing the relationship between the orientation of the wireless tag 30 and the received power intensity when the wireless tag 30 is held close to the human body of the user 2 . In FIG. 4, it can be seen that compared with the case where the wireless tag 30 is placed in front of the transmitting station 10, the reception power intensity is greatly reduced when the wireless tag 30 is placed behind the human body due to the influence of the human body. .

<Location of transmitting station>
From the reception power intensity characteristics described with reference to FIGS. It should be placed in room BD so that it can be done. In the present embodiment, at least two transmitting stations 10 are installed at positions where radio wave line-of-sight is ensured between wireless tags 30 .

More specifically, even if the transmitting station 10 is installed at the height of the ceiling of the room BD and there are a plurality of users 2 in the room BD, the radio signal transmitted by the transmitting station 10 is transmitted to the wireless tag 30. can be received with some strength. Further, by arranging the transmitting station 10 at the four corners of the ceiling of the room BD, it is possible to reliably receive the wireless signal from the transmitting station 10 even when the direction of the wireless tag 30 is changed.

FIG. 5 is a diagram for explaining installation positions of transmitting stations in the position management system according to the first embodiment of the present invention. As described with reference to FIGS. 3 and 4, in this embodiment, the wireless tag 30 is held close to the human body of the user 2, so the wireless signal received by the wireless tag 30 is affected by the human body. It is assumed that the Moreover, it is assumed that the received power of the radio signal also fluctuates depending on the orientation of the user 2 holding the radio tag 30 .

Therefore, in the present embodiment, at least two transmitting stations 10 are installed at positions where radio wave line-of-sight is ensured between the wireless tags 30 . As a result, the wireless tag 30 can be configured to receive wireless signals from at least two transmitting stations 10 . In the configuration example of FIG. 5, by installing the transmitting station 10 at the height of the ceiling of the room BD, even if there are a plurality of users 2 in the room BD, the radio transmitted by the transmitting station 10 in the wireless tag 30 can be detected. A signal can be received with a certain degree of strength without being affected by other users 2 .

<Position estimation in the position management system>
6 and 7 are diagrams for explaining the position estimation technique in the position management system according to the first embodiment of the present invention. In FIG. 6, two transmitting stations 10 with relatively high received power intensity are selected, and using the received power intensities of the radio signals transmitted from the selected two transmitting stations 10 in the wireless tag 30, the Y-axis direction The position of the wireless tag in the direction of the X-axis is estimated using information on the height of the wireless tag 30 held by the human body.

Specifically, it is specified from the height of the wireless tag 30 and the circular curve specified from the intersection of the spheres of equal received power intensities specified from the received power intensities of the radio signals transmitted from the two transmitting stations 10. A candidate for the position of the wireless tag in the X-axis direction is detected from the intersection of the planes.

As for the position of the wireless tag in the X-axis direction, two candidates for the position in the X-axis direction inside and outside the room BD are detected. By selecting the position of the wireless tag in the X-axis direction within the room BD within the range surrounded by the installation position, the position of the wireless tag in the X-axis direction can be estimated.

In this embodiment, the height of the wireless tag 30 held by the human body is used to estimate the area where the wireless tag is present. Even if the radio signal transmitted from 10 cannot be received, it is possible to realize highly accurate position estimation using conventional radio tag functions without implementing any special function in the radio tag.

Here, the height of the wireless tag 30 held by the human body differs depending on the height of the user 2 and the posture in the room BD. Further, it is assumed that the positional errors in the X-axis direction and the Y-axis direction due to the fluctuation range are within the same range. When estimating the area, the influence of the width of variation in the height of the wireless tag 30 is considered to be small.

In FIG. 3-7, the case of estimating the position of the wireless tag 30 by selecting the corresponding transmitting station 10 using the information of the received power intensity of the wireless tag 30 was explained. Alternatively, information on the reading status of the received signal in the wireless tag 30 may be used. For example, a signal transmitted from the transmitting station 10 is received a plurality of times, and the corresponding transmitting station 10 is selected based on whether the number of times the information of the transmitting station ID contained in the received signal has been read is large. The position of the tag 30 may be estimated. In this case, the transmitting station 10 may be selected based on both information indicating whether the received power strength is relatively high and whether the number of readings is relatively high. The transmitting station 10 may be selected based on either condition that the number of readings in the tag is relatively large.

<Configuration of position management device>
FIG. 8 is a configuration example of a location management device in the location management system according to the first embodiment of the present invention. The position management device 100 includes an environmental equipment control unit 101 that estimates the position of the wireless tag 30, a transmission station, a wireless tag reader, a position information management unit 102 that manages the position of the wireless tag, position information of the transmission station, wireless tag reader, and wireless tag. , an input unit 104 for inputting various data such as position information, a display unit 105 for displaying various data such as position information of the wireless tag 30, the transmitting station 10, the wireless tag reader 20, and the network NW An I/F section 106 for connection is provided. The position management device 100 can be realized by a computer having a CPU, memory, and an interface.

<Transmitting station location management data>
FIG. 9 is an example of position management data of a transmitting station according to the first embodiment of the present invention. In the position management data of FIG. 9, position information is registered for each transmitting station 10 installed in the room BD of the building. The position of the wireless tag 30 is estimated using the position information of the transmitting station 10 and the reception strength information of the wireless signal received by the wireless tag 30 . This positional information of the transmitting station 10 is sufficient if the relative positional relationship between the transmitting station 10 and the wireless tag 30 can be specified, and does not necessarily have to be absolute positional information such as latitude/longitude. The same applies to FIG. 10 as well.

<Wireless tag location management data>
FIG. 10 is an example of position management data of wireless tags according to the first embodiment of the present invention. In the position management data shown in FIG. 10, the transmitting station 10 associated with each tag ID of the wireless tag 30 based on the received power intensity information is registered. In the position management data, the area where the wireless tag 30 exists in the room BD is registered using information on the associated installation position of the transmitting station 10 and information on the height of the wireless tag 30 held by the human body. be done. When the information on the number of readings of the transmitting station ID is used for estimating the position of the wireless tag 30, the information on the number of readings is also registered in addition to the information on the received power intensity.

<Environment control sequence>
FIG. 11 is a diagram showing an example of an operation sequence of the environment control method according to the first embodiment of the invention. A user 2 who uses a predetermined room BD in the building is given a wireless tag 30 for specifying an area within the room. Location information of the transmitting station 10 shown in FIG. 9 and information of the wireless tag 30 shown in FIG. 10 are registered in the location management device 100 .

The wireless tag 30 receives the wireless signal transmitted from the transmitting station 10 and transmits to the wireless tag reader 20 information in which the tag ID of the wireless tag 30, the transmitting station ID of the transmitting station 10, and the received power intensity are associated with each other.

The wireless tag ID, the transmitting station ID of the transmitting station 10, and the received power intensity information are transmitted to the position management device 100 and registered in the position management data as shown in FIG. However, at this stage, the area information of the wireless tag 30 is not registered. When the information on the number of readings of the transmitting station ID is used for estimating the position of the wireless tag 30, the information on the number of readings is transmitted in addition to the information on the received power intensity.

The position management device 100 estimates the corresponding transmitting station 10 using the received power intensity information included in the received information. Estimation of the corresponding transmitting station 10 is performed by selecting a transmitting station 10 with relatively high received power intensity. The area in which the wireless tag 30 exists in the room BD is estimated using the information on the installation position of the transmitting station 10, the information on the received power intensity, and the information on the height of the wireless tag 30 held by the human body. , the estimation result is registered in the position management data of FIG.

As described above, in the position management system of the present embodiment, a wireless tag held close to a user's body at a predetermined height and at least two transmitting stations transmit radio waves between the wireless tag and the wireless tag. Information on the installation positions of the two transmitting stations, which are installed in positions where line-of-sight is secured and whose received power strength in the wireless tag is relatively high, and information on the height at which the wireless tag is held by the human body. is used to estimate the area where the wireless tag is present. According to this embodiment, by using the height information of the wireless tag held by the human body, a special function is implemented in the wireless tag even when the wireless tag is held near the human body. Therefore, it is possible to realize highly accurate position estimation.

<Second Embodiment>
FIG. 12 is another configuration example of the location management system according to the second embodiment of the present invention. The configuration example of FIG. 12 differs from the configuration of FIG. 1 in that a reference tag 40 is installed at a predetermined position in the room BD and associated with the transmitting station 10 . In the configuration example of FIG. 12, four reference tags 40 associated with two transmitting stations are installed. It is installed in an orientation that allows reception with strong received power intensity.

In the configuration example of FIG. 13, reference tags #1, #2, #3, and #4 correspond to transmitting stations (#1, #4), transmitting stations (#1, #2), transmitting stations (#2, #2), respectively. 3), associated with the transmitting stations (#3, #4). In this embodiment, when estimating the transmitting station 10 corresponding to each wireless tag 30, the related reference tag 40 is estimated, and the transmitting station 10 associated with the related reference tag 40 is assigned to the wireless tag 30. Estimated as the corresponding transmitting station 10 .

By estimating the corresponding transmitting station 10 via the reference tag 40 associated with the predetermined transmitting station 10 in advance, the estimation accuracy of the corresponding transmitting station 10 can be improved. For example, when it is difficult to estimate the corresponding transmitting station 10 only with the information of the received power strength of radio signals from a plurality of transmitting stations 10, first, the reference tag 40 having similar information of the received power strength is selected. The transmitting station 10 estimated and associated with its associated reference tag 40 can be estimated as the transmitting station 10 corresponding to the radio tag 30 .

FIG. 14 is an example of reference tag management data according to the second embodiment of the present invention. Information on the transmitting station 10 corresponding to each reference tag 40 and information on the received power intensity measured in advance are registered in the reference tag management data. By comparing this received power intensity information with the received power intensity information in the wireless tag 30, the reference tag 40 having similar correlated received power intensity information is estimated, and the associated reference tag 40 The associated transmitting station 10 can be estimated as the transmitting station 10 corresponding to the wireless tag 30 .

FIG. 15 is another example of position management data of wireless tags according to the second embodiment of the present invention. In the position management data of FIG. 15, in addition to the position management data of FIG. 10, related reference tag information is registered.

FIG. 16 is a diagram showing another example of the operation sequence of the location management system according to the second embodiment of the invention. Compared to the operation sequence of FIG. 11, the points are that the information of the received power intensity of the reference tag 40 is registered, and that the related reference tag 40 is estimated when estimating the transmitting station 10 corresponding to the wireless tag 30. different.

<Modification of Embodiment>
Although the embodiments of the location management system of the present invention have been described above, the present invention is not limited to the described embodiments, and various modifications that a person skilled in the art can assume within the scope of the invention described in the claims. Transformations are possible.

DESCRIPTION OF SYMBOLS 1... Location management system, 2... User, 10... Transmission station, 20... Wireless tag reader, 30... Wireless tag, 40... Reference tag, 100... Location management apparatus.

Claims (4)

a plurality of transmitting stations installed at predetermined installation positions in a room divided into a plurality of areas and transmitting first wireless signals containing unique identification information;
a wireless tag that receives the first wireless signal transmitted by the transmitting station and transmits a second wireless signal that includes unique identification information;
a wireless tag reader that collects the received power intensity of the first wireless signal transmitted by the transmitting station in the wireless tag by receiving the second wireless signal;
a location management device for estimating an area in the room where the wireless tag exists, using information on the received power intensity of the wireless tag and installation location information of the transmitting station;
The wireless tag is held close to the human body at a predetermined height of the human body of a user of the room,
The transmitting stations are installed at positions where at least two of the transmitting stations have radio wave line-of-sight with the wireless tags,
The position management device stores information on the installation positions of at least two of the transmitting stations selected based on the received power intensity of the wireless tag and information on the height of the wireless tag held by the human body. a location management system that estimates the area in the room where the wireless tag is located. The wireless tag reader collects, in addition to the received power intensity, the number of times of reading unique identification information of the transmitting station included in the first wireless signal in the wireless tag,
The position management device includes information on the installation positions of the at least two transmitting stations selected based on at least one of the received power intensity and the number of readings in the wireless tag, and 2. The position management system according to claim 1, wherein the height information held is used to estimate the area in the room where the wireless tag is present. The location management device selects at least two transmitting stations based on at least one of the conditions that the received power intensity of the wireless tag is relatively large or the number of times that the wireless tag is read is relatively large. 3. The location management system of claim 2, which selects. a reference tag that is pre-associated with the transmitting station, is installed at a predetermined position in the room, receives a radio signal transmitted by the transmitting station, and transmits a radio signal containing unique identification information;
The location management device
estimating a specific reference tag correlated with the wireless tag using strength information of wireless signals in the wireless tag and the reference tag;
The wireless tag in the room based on the predetermined position of the specific transmitting station associated with the specific reference tag and strength information of the wireless signal transmitted by the specific transmitting station in the wireless tag. 4. The position management system according to any one of claims 1 to 3, wherein the existing area is estimated.

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