Location Management System

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

[Technical Field]

[0001] The present invention relates to a location management system that estimates the location of a user within a building using wireless technology. [Background technology]

[0002] Conventionally, systems have been proposed that use wireless technology to determine the location of a user within a building. In such positioning systems, wireless signals transmitted from multiple base stations installed at fixed locations within the building are received by a slave station carried by the user, and the slave station's distance from the base station is estimated using the received signal strength, thereby estimating the location of the slave station moving within the building. In such positioning systems using wireless communication between the base station and the slave station, improving the accuracy of positioning is a common challenge.

[0003] For example, Patent Document 1 proposes a location detection system that includes multiple transmitting / receiving stations installed at predetermined locations and a transmitting station consisting of a passive tag, in which the transmitting station has the function of transmitting radio waves modulated with a unique beacon signal, and the multiple transmitting / receiving stations receive the radio waves transmitted by the transmitting station, and the location of the transmitting station is identified using the received power intensity of the radio waves.

[0004] Furthermore, Patent Document 2 proposes a positioning system that includes multiple base units installed at fixed locations, multiple slave units consisting of active tags that are mobile terminals, and passive tags installed at fixed locations. The positioning system proposed in Patent Document 2 estimates the location of the slave units using signals transmitted from the multiple base units installed at fixed locations, as well as signals transmitted from the slave units that receive signals from the passive tags at fixed locations. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-236166 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-152133 [Non-patent literature]

[0006] [Non-Patent Document 1] Soichiro Morishita et al., "Person Identification in Video Images Using UHF RFID," Journal of the Japan Society for Precision Engineering, Vol. 81, No. 6, 2015, pp. 589-597 Summary of the Invention [Problem to be solved by the invention]

[0007] The position detection systems and positioning systems in Patent Documents 1 and 2 use wireless tags as slave units, which allows for highly accurate position estimation at lower cost, but they perform so-called triangulation, which causes a problem that the accuracy of position estimation decreases if signals cannot be sent and received with three or more master units or slave units.In particular, because radio waves in the frequency band used by wireless tags have low water permeability, when a wireless tag is held near a human body, signals cannot be sent and received with three or more master units or slave units, which causes a problem that highly accurate position estimation cannot be performed (see, for example, Non-Patent Document 1).

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a location management system that enables highly accurate location estimation even when a wireless tag is held near a human body. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the location management system of the present invention comprises a plurality of transmitting stations installed at predetermined installation positions in a room divided into a plurality of areas and transmitting a first radio signal including unique identification information; a radio tag that receives the first radio signal transmitted by the transmitting stations and transmits a second radio signal including unique identification information; a radio tag reader that collects the received power strength of the first radio signal transmitted by the transmitting stations at the radio tag by receiving the second radio signal; and a location management device that estimates the area in the room where the radio tag is located using information on the received power strength at the radio tag and information on the installation positions of the transmitting stations, wherein the radio tag is held in close proximity to the human body of a user of the room at a predetermined height from the human body, and the transmitting stations are installed at positions where radio wave line of sight is ensured between at least two of the transmitting stations and the radio tag, and the location management device estimates the area in the room where the radio tag is located using information on the installation positions of at least two of the transmitting stations selected based on the received power strength at the radio tag and information on the height at which the radio tag is held on the human body. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a location management system that enables highly accurate location estimation even in cases where a wireless tag is held in the vicinity of a human body. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows an example of the configuration of a location management system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the location management technology in the location management system according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram for explaining the reception characteristics of a radio signal in the radio tag according to the first embodiment of the present invention. [Figure 4]FIG. 4 is a diagram for explaining the reception characteristics of a radio signal in the radio tag according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a diagram for explaining the installation positions of transmitting stations in the location management system according to the first embodiment of the present invention. [Figure 6] 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. [Figure 7] 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. [Figure 8] FIG. 8 shows an example of the configuration of a location management device according to the first embodiment of the present invention. [Figure 9] FIG. 9 shows an example of location management data of a transmitting station according to the first embodiment of the present invention. [Figure 10] FIG. 10 shows an example of location management data of the wireless tag according to the first embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing an example of an operation sequence of the location management system according to the first embodiment of the present invention. [Figure 12] FIG. 12 shows an example of the configuration of a location management system according to the second embodiment of the present invention. [Figure 13] FIG. 13 is a diagram for explaining a location management technique in a location management system according to the second embodiment of the present invention. [Figure 14] FIG. 14 is an example of management data of a reference tag according to the second embodiment of the present invention. [Figure 15] FIG. 15 shows an example of location management data of a wireless tag according to the second embodiment of the present invention. [Figure 16] FIG. 16 is a diagram showing an example of an operation sequence of the location management system according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0013] First Embodiment <Configuration of location management system> 1 shows an example of the configuration of a location management system according to a first embodiment of the present invention. The location management system 1 includes a plurality of transmitting stations 10 installed at predetermined positions in a predetermined room BD in a building and transmitting a radio signal (first radio signal) containing unique identification information; a radio tag 30 that receives the radio signal transmitted by the transmitting station 10 and transmits a radio signal (second radio signal) containing unique identification information; a radio tag reader 20 installed at a predetermined position in the predetermined room BD in the building and receiving the radio signal from the radio tag 30; and a location management device 100 connected to the plurality of transmitting stations 10 and the radio tag reader 20 via a network NW and that manages the location of the radio tag 30 in the predetermined room BD in the building. The radio tag 30 is held in proximity to the body of a user 2 in the room BD at a predetermined height from the body.

[0014] In the configuration example of Fig. 1, four transmitting stations 10 and four wireless tag readers 20 are installed at predetermined positions in room BD. At least two transmitting stations 10 are installed at positions where radio wave line of sight is ensured between them and wireless tags 30. Wireless tags 30 are attached to users 2 when they enter room BD in a building, and are used to identify the location of user 2 within the area. Wireless tags 30 receive wireless signals transmitted by transmitting stations 10, wireless tag readers 20 collect information on the received power strength of wireless tags 30, and location management device 100 estimates the location of wireless tags 30 using the collected information on the received power strength.

[0015] The location management device 100 is connected to a plurality of transmitting stations 10 and wireless tag readers 20 via a network NW. The locations of the plurality of transmitting stations 10 and wireless tag readers 20 are registered in advance in the location management device 100. The location management device 100 estimates the area in the room BD where the wireless tags are present, using information on the received power strength of the wireless tags 30 and installation location information of the transmitting stations 10.

[0016] <Location management in a location management system> 2 is a diagram illustrating a location management technique in a location management system according to a first embodiment of the present invention. In the location management system of this embodiment, a wireless tag 30 is held at a predetermined height from the body of a user 2 in a room BD. Utilizing this, the area in the room BD where the wireless tag 30 exists is estimated using information on the installation locations of at least two transmitting stations 10 with relatively high received power strength at the wireless tag 30 and information on the height at which the wireless tag 30 is held on the body. In the example of FIG. 2, the room BD is divided into nine areas (CA#1 to CA#9), and the area where the wireless tag 30 exists is estimated from among the areas (CA#1 to CA#9) using the received power strength of wireless signals transmitted by the two transmitting stations 10 at the wireless tag 30.

[0017] <Reception characteristics of wireless tags> 3 and 4 are diagrams illustrating the reception characteristics of a radio signal in a radio tag according to a first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the orientation of the radio tag 30 and the received power intensity. As shown in FIG. 2, it can be seen that the received power intensity varies greatly depending on the orientation of the radio tag 30. FIG. 4 is a diagram showing the relationship between the orientation of the radio tag 30 and the received power intensity when the radio tag 30 is held close to the body of a user 2. It can be seen from FIG. 4 that the received power intensity is significantly reduced due to the influence of the human body when the radio tag 30 is placed behind the human body, compared to when the radio tag 30 is placed in front of the transmitting station 10.

[0018] <Location of transmitting station> 3 and 4, the transmitting stations 10 used to estimate the position of the wireless tag 30 need to be placed in the room BD so that the wireless tag 30 can receive wireless signals transmitted from at least two transmitting stations 10. In this embodiment, at least two transmitting stations 10 are installed in positions where radio wave line of sight is ensured between the transmitting stations 10 and the wireless tag 30.

[0019] More specifically, the transmitting station 10 is installed at the height of the ceiling of the room BD, and even if there are multiple users 2 in the room BD, the wireless tag 30 can receive the wireless signal transmitted from the transmitting station 10 with a certain degree of strength. Furthermore, by arranging the transmitting stations 10 at the four corners of the ceiling of the room BD, it is possible to configure the wireless tag 30 to reliably receive the wireless signal from the transmitting station 10 even if the orientation of the wireless tag 30 changes.

[0020] 5 is a diagram illustrating the installation positions of transmitting stations in the location 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 in close proximity to the body of the user 2, and therefore it is expected that the wireless signal received by the wireless tag 30 will be attenuated by the influence of the human body. It is also expected that the received power of the wireless signal will vary depending on the orientation of the user 2 holding the wireless tag 30.

[0021] Therefore, in this embodiment, at least two transmitting stations 10 are installed in positions where radio wave line of sight is ensured between the wireless tag 30 and the transmitting stations 10. This allows the wireless tag 30 to receive wireless signals from at least two transmitting stations 10. In the configuration example of Fig. 5, by installing the transmitting stations 10 at the height of the ceiling of the room BD, even if there are multiple users 2 in the room BD, the wireless tag 30 can receive the wireless signal transmitted from the transmitting stations 10 with a certain degree of strength without being affected by the other users 2.

[0022] <Location estimation in location management systems> 6 and 7 are diagrams for explaining the position estimation technology in the position management system according to the first embodiment of the present invention. In Fig. 6, two transmitter stations 10 with relatively high received power strength are selected, and the position of the wireless tag 30 in the Y-axis direction is estimated using the received power strength of the wireless signals transmitted from the selected two transmitter stations 10, and further the position of the wireless tag 30 in the X-axis direction is estimated using information on the height at which the wireless tag 30 is held by the human body.

[0023] Specifically, a candidate position of the wireless tag in the X-axis direction is detected from the intersection of a circular curve identified from the intersection of spherical surfaces of equal reception power strength identified from the reception power strength of wireless signals transmitted from two transmitting stations 10 and a plane identified from the height of the wireless tag 30.

[0024] Regarding the position of the wireless tag in the X-axis direction, two candidate positions in the X-axis direction, inside and outside the room BD, are detected. From among the detected candidates, the position of the wireless tag in the X-axis direction within the room BD, within the range surrounded by the installation positions of the four transmitting stations 10 in Figure 7, can be selected to estimate the position of the wireless tag in the X-axis direction.

[0025] In this embodiment, the area in which the wireless tag is located is estimated by utilizing the height at which the wireless tag 30 is held on the human body. Therefore, even if the wireless tag 30 cannot receive wireless signals transmitted from three or more transmitting stations 10, highly accurate position estimation can be achieved using the functions of conventional wireless tags without implementing any special functions in the wireless tag.

[0026] Here, the height at which the wireless tag 30 is held on the human body varies depending on the height of the user 2 and their posture within the room BD, but it is expected that the fluctuation range of the height of the wireless tag 30 due to these factors will be within a range of several tens of centimeters or less, and furthermore, it is expected that the positional errors in the X-axis and Y-axis directions due to this fluctuation range will be within a similar range, so when estimating the area within the room BD where the wireless tag 30 is located, it is thought that the fluctuation range of the height of the wireless tag 30 will have little effect.

[0027] 3-7 illustrates a case where the location of the wireless tag 30 is estimated by selecting a corresponding transmitting station 10 using information on the received power strength of the wireless tag 30. However, in addition to the information on the received power strength, information on the read status of the received signal in the wireless tag 30 may also be used. For example, a signal transmitted from the transmitting station 10 may be received multiple times, and the corresponding transmitting station 10 may be selected based on the number of times that the information on the transmitting station ID included in the received signal has been successfully read, thereby estimating the location of the wireless tag 30. In this case, the transmitting station 10 may be selected based on both information on whether the received power strength is relatively high and information on the number of times that the reading has been performed, or the transmitting station 10 may be selected based on either the condition on whether the received power strength is relatively high or the condition on whether the number of times that the wireless tag has been read is relatively high.

[0028] <Configuration of location management device> 8 shows an example of the configuration of a location management device in a location management system according to a first embodiment of the present invention. The location management device 100 includes an environmental equipment control unit 101 that estimates the location of a wireless tag 30, a location information management unit 102 that manages the locations of a transmitting station, a wireless tag reader, and a wireless tag, a memory unit 103 that stores location information for the transmitting station, the wireless tag reader, and the wireless tag, an input unit 104 that inputs various data such as location information, a display unit 105 that displays various data such as the location information for the wireless tag 30, and an I / F unit 106 for connecting to the transmitting station 10 and the wireless tag reader 20 via a network NW. The location management device 100 can be realized by a computer equipped with a CPU, memory, and an interface.

[0029] <Transmitting station location management data> Fig. 9 is an example of location management data of a transmitting station according to the first embodiment of the present invention. In the location management data of Fig. 9, location information is registered for each transmitting station 10 installed in a room BD of a building. The location of the wireless tag 30 is estimated using the location information of this transmitting station 10 and reception strength information of the wireless signal received by the wireless tag 30. The location information of this transmitting station 10 is sufficient as long as it can identify the relative positional relationship between the transmitting station 10 and the wireless tag 30, and does not necessarily have to be absolute location information such as latitude / longitude. The same applies to Fig. 10.

[0030] <Location management data of wireless tags> Fig. 10 is an example of location management data of a wireless tag according to the first embodiment of the present invention. In the location management data shown in Fig. 10, a transmitter 10 associated with each tag ID of a wireless tag 30 based on information on received power intensity is registered. The location management data registers the area in which the wireless tag 30 exists in the room BD using information on the installation location of the associated transmitter 10 and information on the height at which the wireless tag 30 is held by the human body. When information on the number of times the transmitter ID has been read is used to estimate the location of the wireless tag 30, information on the number of times the wireless tag 30 has been read is also registered in addition to information on received power intensity.

[0031] <Environmental control sequence> 11 is a diagram showing an example of an operation sequence of the environment control method according to the first embodiment of the present invention. A user 2 using a specific room BD of a building is given a wireless tag 30 for identifying the area within the room. The location management device 100 has registered therein the location information of the transmitting station 10 shown in FIG. 9 and the information of the wireless tag 30 shown in FIG. 10.

[0032] 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.

[0033] The information on the wireless tag ID, the transmitting station ID of the transmitting station 10, and the received power intensity is transmitted to the location management device 100 and registered in the location management data as shown in Fig. 10. However, at this stage, the area information of the wireless tag 30 has not been registered. When information on the number of times the transmitting station ID has been read is used to estimate the location of the wireless tag 30, information on the number of times the reading has been performed is transmitted in addition to information on the received power intensity.

[0034] The location management device 100 uses information on the received power intensity included in the received information to estimate the corresponding transmitting station 10. The corresponding transmitting station 10 is estimated by selecting a transmitting station 10 with a relatively high received power intensity. The area in room BD where the wireless tag 30 is located is estimated using information on the installation location of the associated transmitting station 10, information on the received power intensity, and information on the height at which the wireless tag 30 is held on the human body, and the estimation result is registered in the location management data in FIG. 10.

[0035] As described above, the location management system of this embodiment is configured to estimate the area where a wireless tag is located by using information on the installation locations of two transmitting stations with relatively high received power strength at the wireless tag, which are installed in proximity to a wireless tag held at a predetermined height of the user's body and at least two transmitting stations in positions where radio wave line-of-sight is ensured between the wireless tag and the transmitting stations, and information on the height at which the wireless tag is held on the human body. According to this embodiment, by using information on the height at which the wireless tag is held on the human body, it is possible to achieve highly accurate location estimation without implementing any special functions in the wireless tag, even when the wireless tag is held near the human body.

[0036] <Second embodiment> Fig. 12 shows another example of the configuration of a location management system according to the second embodiment of the present invention. The example of the configuration in Fig. 12 differs from the configuration in Fig. 1 in that it includes reference tags 40 that are installed at predetermined positions in a room BD and that are associated with transmitting stations 10. In the example of the configuration in Fig. 12, four reference tags 40 that are associated with two transmitting stations are installed, and each reference tag 40 is installed in an orientation such that it can receive the radio signal transmitted by the associated transmitting station 10 with a relatively strong reception power strength.

[0037] 13, reference tags #1, #2, #3, and #4 are associated with transmitting stations (#1, #4), transmitting stations (#1, #2), transmitting stations (#2, #3), and transmitting stations (#3, #4), respectively. In this embodiment, when estimating the corresponding transmitting station 10 for each wireless tag 30, the related reference tag 40 is estimated, and the transmitting station 10 associated with the related reference tag 40 is estimated as the transmitting station 10 corresponding to the wireless tag 30.

[0038] The accuracy of estimating the corresponding transmitting station 10 can be improved by estimating the corresponding transmitting station 10 via a reference tag 40 that has been previously associated with a specific transmitting station 10. For example, when it is difficult to estimate the corresponding transmitting station 10 using only information on the received power strength of radio signals from multiple transmitting stations 10, it is possible to first estimate a reference tag 40 that has information on similar received power strength, and then estimate the transmitting station 10 associated with the related reference tag 40 as the transmitting station 10 corresponding to the wireless tag 30.

[0039] 14 shows an example of management data for reference tags according to the second embodiment of the present invention. The management data for the reference tags includes information on the transmitting stations 10 corresponding to each reference tag 40 and information on received power intensity measured in advance. By comparing this received power intensity information with the received power intensity information of the wireless tag 30, reference tags 40 having similar correlated received power intensity information can be identified, and the transmitting station 10 associated with the related reference tag 40 can be identified as the transmitting station 10 corresponding to the wireless tag 30.

[0040] Fig. 15 shows another example of location management data of a wireless tag according to the second embodiment of the present invention. In the location management data of Fig. 15, in addition to the location management data of Fig. 10, information on related reference tags is registered.

[0041] Fig. 16 is a diagram showing another example of the operation sequence of the location management system according to the second embodiment of the present invention. Compared to the operation sequence of Fig. 11, it differs in that information on the received power strength of the reference tag 40 is registered, and that when estimating the transmitting station 10 corresponding to the wireless tag 30, the associated reference tag 40 is estimated.

[0042] <Modifications of the embodiment> The above describes an embodiment of the location management system of the present invention, but the present invention is not limited to the described embodiment, and various modifications that a person skilled in the art can make within the scope of the invention described in the claims are possible. [Explanation of symbols]

[0043] 1...location management system, 2...user, 10...transmitting station, 20...wireless tag reader, 30...wireless tag, 40...reference tag, 100...location management device.

Claims

1. A plurality of transmitting stations installed at predetermined installation positions in a room divided into a plurality of areas and transmitting a first wireless signal including unique identification information; a wireless tag that receives the first wireless signal transmitted by the transmitting station and transmits a second wireless signal including unique identification information; a wireless tag reader that receives the second wireless signal and collects the received power intensity of the first wireless signal transmitted by the transmitting station in the wireless tag; a location management device that estimates an area in the room where the wireless tag is present, using information on the received power strength of the wireless tag and information on the installation location of the transmitting station; Equipped with the wireless tag is held in proximity to the human body of the user of the room at a predetermined height from the human body, the transmitting stations are installed at positions where at least two of the transmitting stations are in line of sight with the wireless tags, the location management device estimates the area in the room where the wireless tag is present, using information on the installation locations of at least two of the transmitting stations selected based on the received power strength of the wireless tag and information on the height at which the wireless tag is held by the human body; a reference tag that is associated with the transmitting station in advance, that is installed at a predetermined position in the room, that receives the first wireless signal transmitted by the transmitting station, and that transmits a third wireless signal including unique identification information to the wireless tag reader; The location management device using received power strength information of the first radio signal at the wireless tag and the reference tag, estimating a specific reference tag correlated with the wireless tag; An area in the room where the wireless tag is present is estimated based on a predetermined position of the specific transmitting station associated with the specific reference tag and strength information of the first wireless signal transmitted by the specific transmitting station in the wireless tag. Location management system.

2. the wireless tag reader collects the number of times the unique identification information of the transmitting station included in the first wireless signal of the wireless tag has been read in addition to the received power strength; The location management device estimates the area in the room where the wireless tag is present using information on the installation locations of at least two of the transmitting stations selected based on at least one of the received power strength and the number of reads of the wireless tag, and information on the height at which the wireless tag is held by the human body. The location management system according to claim 1 .

3. The location management device selects at least two transmitting stations based on at least one of the conditions that the received power strength at the wireless tag is relatively large and the number of times the wireless tag is read is relatively large. The location management system according to claim 2.

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