JP2015106814A - Radio wave transmitting apparatus and position measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave transmitting apparatus that transmits a radio wave transmitted from a radio wave transmitter operated with low power consumption into a predetermined area by restricting directional characteristics.SOLUTION: The radio wave transmitting apparatus includes: a radio wave transmitter that is driven by a battery and transmits a radio wave containing own identification information in a short-range with a transmitting frequency and a transmitting output power preset in advance; and a shielding body that accommodates the radio wave transmitter, regulates radiation of a radio wave transmitted from the radio wave transmitter into a specific direction, and transmits the radio wave into a predetermined area.

Description

  Embodiments described herein relate generally to a position measurement system including a radio wave transmission device that transmits radio waves in a short-range wireless manner, a mobile terminal that receives radio waves from the radio wave transmission device, and a management server that can communicate with the mobile terminal.

  Conventionally, a position measurement system (positioning system) that specifies a current position of a moving body (moving person) indoors or the like has been used. For example, in various facilities, a positioning system installs radio wave transmitters at a plurality of locations in a facility, and a mobile terminal is held by a mobile person, receives radio waves from the radio wave transmitter with the mobile terminal, and receives the mobile terminal. Based on the information, it is possible to check on the server where the mobile person is currently located.

  As the mobile terminal, for example, a multi-function mobile phone such as a smartphone is used. Bluetooth (registered trademark) is standardly installed in a smartphone as a short-range wireless communication specification, and wireless communication is possible between a radio wave transmitter and a portable terminal.

  However, in the conventional position measurement system, since the radio wave transmitter has a large radio wave output, the radio wave transmitter cannot be operated with low power consumption, and the battery needs to be replaced in about one month. In addition, since the radio wave output from the radio wave transmitter is large, the radio wave reach distance is long (about 10 m) and the antenna of the radio wave transmitter is omnidirectional, so that it is easy to send radio waves to adjacent areas. For this reason, in the case where a plurality of radio wave transmitters are installed, radio waves from other remote transmitters are received. Accordingly, there is a problem that erroneous detection occurs due to interference, and erroneous position information is transmitted to the server. In addition, the transmission interval of the radio wave emitted from the radio wave transmitter is fixed at once per second or the like, and there is a problem that the power consumption becomes high.

JP 2011-145873 A

  SUMMARY OF THE INVENTION Problems to be Solved by the Invention The problem to be solved by the present invention is that a radio wave transmitter that transmits a predetermined area by narrowing the directivity of radio waves transmitted from a radio transmitter that operates with low power consumption, and a mobile terminal that receives radio waves from the radio transmitter And providing a position measurement system using a management server.

  The radio wave transmitter according to the embodiment wirelessly transmits a radio wave including its own identification information with a preset transmission cycle and transmission output, accommodates the radio wave transmitter driven by a battery, the radio wave transmitter, A shield that restricts radiation of a radio wave transmitted from the radio wave transmitter in a specific direction and transmits the radio wave to a preset area.

The block diagram which shows the whole structure of the position measurement system which concerns on one Embodiment. The lineblock diagram showing the schematic structure of the position measuring system concerning one embodiment. The block diagram which shows the structure of BT-module in one Embodiment. The block diagram which shows the structure of the portable terminal in one Embodiment. The block diagram which shows the structure of the management server in one Embodiment. Explanatory drawing which shows operation | movement of the portable terminal and management server in one Embodiment. 1 is a perspective view showing a radio wave transmitter according to an embodiment. Sectional drawing which shows the state which attached the electromagnetic wave transmitter in one Embodiment to the ceiling. Sectional drawing which shows the modification of the shield of the electromagnetic wave transmitter in one Embodiment. Sectional drawing which shows the 2nd modification of the shielding body in one Embodiment. Sectional drawing which shows the 3rd modification of the shielding body in one Embodiment. Explanatory drawing which shows an example of the measuring method of the received signal strength (RSSI) of the electromagnetic wave by the portable terminal in one Embodiment. The distribution map which shows the 1st example of the measurement result of RSSI in one Embodiment. The distribution map which shows the 2nd example of the measurement result of RSSI in one Embodiment. The distribution map which shows the 3rd example of the measurement result of RSSI in one Embodiment. The distribution map which shows the 4th example of the measurement result of RSSI in one Embodiment. The distribution map which shows the 5th example of the measurement result of RSSI in one Embodiment. The distribution map which shows the 6th example of the measurement result of RSSI in one Embodiment. Explanatory drawing which shows the example of arrangement | positioning of the electromagnetic wave absorber sheet in one Embodiment. The distribution map which shows the measurement result of RSSI in FIG. Explanatory drawing which shows the installation direction of the electromagnetic wave transmitter in one Embodiment. Explanatory drawing which shows the installation position of the electromagnetic wave transmitter in one Embodiment.

  Embodiments for carrying out the invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same location.

(First embodiment)
FIG. 1 is a configuration diagram showing an overall configuration of the position measurement system according to the first embodiment. In the position positioning system, for example, in a facility 100 such as a care facility or a medical facility, radio wave transmitters 10a, 10b,..., 10n are installed in the rooms 1a, 1b,. Further, the mobile persons 50a, 50b, etc., such as caregivers, have the portable terminal 20 and receive radio waves from the radio wave transmitters 10a, 10b,. The mobile terminal 20 communicates with the management server 30 via a communication network such as a wireless LAN, and the management server 30 collects reception information of the mobile terminal 20 to check in which room the mobile person is currently located, It can be displayed on the display.

  The radio wave transmitters 10a, 10b,..., 10n transmit radio waves including their own device information (identification information: ID), and function as indexes (markers) that indicate the position of each radio wave transmitter. In the following description, each of the radio wave transmitters 10a, 10b... 10n is referred to as a marker. Since the markers 10a, 10b,..., 10n have the same configuration, the markers 10a, 10b,.

 The marker 10 and the mobile terminal 20 are each equipped with a Bluetooth (registered trademark) module which is a short-range communication specification. When the mobile terminal 20 enters the radio wave area transmitted from the marker 10, the mobile terminal 20 A radio wave from the marker 10 is received, and device information (ID) unique to the marker 10 is identified. In addition to the device information of the marker 10, the mobile terminal 20 acquires information on the radio wave intensity. In addition, as the portable terminal 20, a multifunctional mobile phone such as a smartphone can be used.

  In FIG. 1, the mobile person 50a holding the mobile terminal 20 is in the room 1e and receives radio waves from the marker 10e, and the mobile person 50b holding the mobile terminal 20 is in the hallway 2a and receives radio waves from the marker 10f. Is shown.

  FIG. 2 is a configuration diagram illustrating a schematic configuration of the position measurement system according to the first embodiment. In FIG. 2, the marker 10 includes a Bluetooth (registered trademark) module 11 (hereinafter referred to as BT-module 11), and operates by using the solar cell 12 or the solar cell 12 and the built-in battery 13 in combination. 11, weak radio waves for detection are periodically transmitted at predetermined time intervals. Since the marker 10 only transmits radio waves and does not have a function of receiving radio waves, the marker 10 can operate with extremely low power consumption. In addition, in order to shine light on the solar cell 12, the marker 10 is preferably attached near an illumination 101 (such as a fluorescent lamp) provided on the ceiling.

  The mobile terminal 20 is, for example, a smartphone. When the mobile terminal 20 receives a detection radio wave from the marker 10, the mobile terminal 20 acquires device information (ID) of the marker 10 and radio wave intensity information. Device information and radio wave intensity information acquired by the mobile terminal 20 are sent to the management server 30 via a communication network such as a wireless LAN. When there are a plurality of portable terminals 20 (for example, when there are portable terminals 20 and 20 ′), communication is performed between the plurality of portable terminals 20 and 20 ′ and the management server 30.

 The management server 30 is configured by, for example, a PC (Personal Computer) or the like, communicates with the mobile terminal 20 via a communication network such as a wireless LAN, and stores the device information and radio wave intensity information acquired by the mobile terminal 20. In addition, the mobile terminal 20 (that is, the mobile persons 50a and 50b) determines the current position and displays it on the display unit 34.

  FIG. 3 is a block diagram illustrating a configuration example of the BT-module 11. The BT module 11 includes a BT-chip 14, a crystal oscillator 15 and a clock generator 16 connected to the BT-chip 14, and further includes an antenna 17 and a band pass filter 18. The BT-module 11 operates by using the solar battery 12 shown in FIG. 2 or the solar battery 12 and the built-in battery 13 in combination, and the short-distance radio wave that conforms to the Bluetooth (registered trademark) communication standard from the BT-chip 14. Is transmitted from the antenna 17 via the band pass filter 18.

  The marker 10 can change a transmission cycle and a transmission output, and transmits a weak radio wave for detection once at an arbitrarily set interval, for example, several hundred milliseconds to several hours. Since the power consumption is inversely proportional to the radio wave transmission interval, the power consumption can be suppressed as the transmission interval is increased. In addition, by reducing the radio wave output by reducing the radio wave output distance, interference with other markers is reduced, positioning errors are reduced, and power consumption during transmission is reduced.

FIG. 4 is a block diagram illustrating a configuration of the mobile terminal 20. The mobile terminal 20 is a mobile phone such as a smartphone, for example, and includes a control unit 21, a storage unit 22, a voice control unit 23, an operation unit 24, and a display unit 25. A second wireless communication unit 27 that performs wireless communication between the unit 26 and the management server 30 is included. Each unit is connected to each other via a bus line 28.
The control unit 21 includes a central processing unit (CPU) that is a controller, and controls the mobile terminal 20 collectively and performs various arithmetic processes. The storage unit 22 includes, for example, a random access memory (RAM) and a read only memory (ROM). The RAM temporarily stores data when the control unit 21 performs processing. The ROM stores programs and data for the control unit 21 to perform processing.

  The voice control unit 23 includes an interface for a microphone and a speaker built in the mobile terminal 20. The display unit 25 displays document data and image data. When the control unit 21 detects that the operation unit 24 is operated by the user, the control unit 21 performs a predetermined process in accordance with the user's instruction.

  The short-range wireless communication unit 26 includes an antenna 261 and receives radio waves from the marker 10. Bluetooth (registered trademark) or the like is used for short-range wireless communication. Under the control of the control unit 21, the short-range wireless communication unit 26 processes a reception signal received via the antenna 261 to acquire device information and radio wave intensity information of the marker 10.

  The wireless communication unit 27 includes an antenna 271, communicates with the management server 30 via a communication network such as a wireless LAN, transmits and receives radio waves, and is received by the short-range wireless communication unit 26 based on the control of the control unit 21. Information and radio wave intensity information are transmitted to the management server 30 via the antenna 271. In addition, the wireless communication unit 27 restores data by processing data from the management server 30 received via the antenna 271. The data is transmitted to the voice control unit 23 according to an instruction from the control unit 21 and output from the speaker, and is displayed on the display unit 25 or recorded in the storage unit 22.

  FIG. 5 is a block diagram of the management server 30. The management server 30 includes a control unit 31, a storage unit 32, an operation unit 33, a display unit 34, and a communication unit 35, and each unit is connected to each other by a bus line 36. The control unit 31 includes a CPU that is a controller, and comprehensively controls the management server 30. The control unit 31 performs various arithmetic processes. The storage unit 32 includes, for example, a RAM and a ROM, and temporarily stores data when the control unit 31 performs processing. In addition, device information (ID) of each marker 10 is registered in the RAM. The ROM stores programs and data for the control unit 31 to perform processing.

  The communication unit 35 communicates with the mobile terminal 20 via a communication network such as a wireless LAN. The communication unit 35 processes the received signal received based on the control of the control unit 31 and restores the data. This data is stored in the storage unit 32 according to an instruction from the control unit 31. Further, the communication unit 35 acquires data stored in the storage unit 32 according to an instruction from the control unit 31 and transmits the data to the mobile terminal 20.

  FIG. 6 is an explanatory diagram showing operations of the mobile terminal 20 and the management server 30. FIG. 6A is an explanatory diagram of the inside of the facility 100 as seen from the plane direction. Markers 10a, 10b, 10c, and 10d are installed in the rooms 3a and 3b, the hall 3c, and the hallway 2b of the facility 100, respectively. A situation is shown in which a mobile person 50a having 20 moves from the hall 3c to the hallway 2b.

  The marker 10 continues to periodically output weak radio waves for detection at preset intervals. The radio wave areas from the markers 10a, 10b, 10c, and 10d are indicated by dotted lines A, B, C, and D. When the mobile terminal 20 enters the range of the radio wave transmitted from the marker 10, the mobile terminal 20 can detect the radio wave for detection periodically transmitted by the marker 10, and acquires device information and radio wave intensity information of the marker 10. .

 FIG. 6B is an explanatory view shown from the side surface direction. When the moving person 50a moves from the radio wave area C toward the radio wave area B, for example, the radio wave intensity from the marker 10c is initially strong, but when entering the radio wave area B, the radio wave intensity from the marker 10b becomes strong. Since the radio wave transmitted from the marker 10 reaches only about a few meters, when the mobile terminal 20 receives the radio wave, it is within a range of a few meters from the marker 10 and shortens the time required for searching for the marker 10. it can.

 As illustrated in FIG. 6B, the mobile terminal 20 transmits the device information of the marker 10 and the information of the radio wave intensity to the management server 30 and inquires of the management server 30 about the received device information of the marker 10. In response to this inquiry, the management server 30 determines the installation location of the marker 10 and the current position of the mobile terminal 20 based on the device information of the marker 10 and the information of the radio wave intensity, and registers them in the storage unit 32 of the management server 30. And transmitted to the mobile terminal 20.

 For example, by comparing the radio wave intensity from each marker 10 received by the mobile terminal 20, it can be determined that the marker 10 having the higher radio wave intensity is approaching. Moreover, since the device information (ID) of each marker 10 is stored in the storage unit 32 of the management server 30, the device information from the mobile terminal 20 and the device information stored in the storage unit 32 are collated, so that the mobile terminal It is possible to determine which marker 10 is currently 20 close to.

 Therefore, the mobile terminal 20 can obtain information on the installation position of the marker 10 from the management server 30 and obtain the current position. Further, the mobile terminal 20 may arbitrarily set the inquiry interval to the management server 30. The power consumption of the portable terminal 20 can be reduced by arbitrarily setting the inquiry interval.

  Moreover, the management server 30 can obtain the action history of the mobile terminal 20 (moving person 50a) at the place where the marker 10 is installed by continuously recording the inquiry history of the device information of the marker 10 from the mobile terminal 20. . For example, as shown in FIG. 6 (a), when there is an inquiry about device information in the order of markers 10c → 10d → 10b, it can be seen that the hall 10c has moved to the hallway 2b and the room 10b.

  In addition, the management server 30 can display which area the moving person 50a is in or through which route by receiving the device information of the marker 10 and the information on the radio wave intensity from the portable terminal 20. it can. For example, the management server 30 displays the map 37 of the facility 100 on the display unit 34 of the management server 30 and transmits the device information and the radio wave intensity information received from the marker 10 by the mobile terminal 20 to the management server 30. It is possible to display on the map 37 which position (which room) the moving person 50a is currently in. FIG. 6B illustrates that the moving person 50 a is present at the position of the marker 10 d on the map 37.

  Since the antenna 17 of the marker 10 is omnidirectional, radio waves are radiated from the ceiling toward the floor, and are radiated toward the back of the ceiling, adjacent rooms, and the like. For this reason, in order to suppress the radio wave from the marker 10 from leaking to the upper floor room, the adjacent room, etc., it is necessary to give directivity characteristics so as to radiate in the desired direction. In the radio wave areas A, B, and C in FIG. 6B, the directivity is devised so as to radiate from the ceiling toward the floor.

 FIG. 7 is a perspective view showing a specific example of a radio wave transmission device including a marker 10 (radio wave transmitter) and a shield 40. The shield 40 accommodates the radio wave transmitter 10, restricts the radiation of radio waves transmitted from the radio wave transmitter 10 in a specific direction, and transmits the radio waves to a predetermined area so that the directivity characteristic in a specific direction is obtained. Is to give.

  In FIG. 7, the marker 10 includes a BT-module 11, a solar battery 12, a built-in battery 13, an antenna 17, and a power switch 18. The marker 10 is accommodated in a shield 40 having an opening 41.

  The shield 40 includes a metal body 42 and a radio wave absorber 43. The radio wave absorber 43 is formed in a box shape having an opening 41, and a metal body 42 (aluminum tape) is attached to the outer peripheral surface of the radio wave absorber 43. By accommodating the marker 10 inside the radio wave absorber 43, radio waves can be transmitted from the marker 10 to a specific area outward from the opening 41 of the shield 40. The shield 40 may have a structure in which the metal body 42 is formed in a box shape and the radio wave absorber 43 is attached to the inner peripheral surface thereof.

  As the radio wave absorber 43, for example, MS-F010 manufactured by Radio Wave Absorber Co., Ltd. can be used. Further, the opening 41 may be covered with the spacer 51 after the marker 10 is accommodated in the shield 40. For example, the marker 10 is attached to the ceiling so that the opening 41 of the shield 40 is on the lower side in a state of being accommodated in the shield 40. Moreover, in order to irradiate the solar cell 12 with illumination light such as a fluorescent lamp, when the spacer 51 is covered, the spacer 51 may be made of a translucent material.

  FIG. 8 is a cross-sectional view showing a state in which the radio wave transmitter is attached to the ceiling 102. The marker 10 constituting the radio wave transmitting apparatus is accommodated in the shield 40 and a spacer 51 is inserted through the opening 41. By inserting the spacer 51 deeply, the end face of the marker 10 is not flush with the opening 41 and is attached in a state of being retracted by a predetermined offset amount H to the back side of the shield 40 from the opening 41. The attachment to the ceiling 102 is performed using a fixture such as a magnet. As the offset amount H is larger, the end face of the marker 10 is retracted than the opening 41, so that the directivity can be adjusted so that the radiation angle α of the radio wave becomes narrower. Therefore, radiation to adjacent rooms can be reduced.

  FIGS. 9-11 shows the modification of the shield 40 in a radio wave transmitter. In FIG. 9, the shield 40 is attached only to the upper surface of the marker 10. The shield 40 is composed only of a flat metal body. By attaching the shield 40 to the upper surface of the marker 10, it is possible to prevent radio waves from being emitted to the upper floor room. However, since the radio wave is reflected by the shield 40 (metal body) and the propagation characteristic of the radio wave becomes uneven as indicated by the dotted line E, there is a concern that the radio wave reception state at the mobile terminal 20 may become unstable. The

  FIG. 10 shows a state in which the marker 10 is housed in the shield 40 in which the radio wave absorber 43 is mounted on the inner peripheral surface of the metal body 42, and the opening 41 of the shield 40 and the end surface of the marker 10 are flush with each other. It does not have an offset amount. The presence of the radio wave absorber 43 can prevent the radio wave from being reflected by the metal body 42, the radio wave propagation characteristics become uniform as indicated by the dotted line F, and the radio wave reception state at the mobile terminal 20 is Stabilize.

  FIG. 11 shows a state in which the marker 10 is accommodated in the shield 40 having the radio wave absorber 43 attached to the inner peripheral surface of the metal body 42, and the opening of the shield 40 is covered with another radio wave absorber sheet 431. Indicates. The radio wave absorber sheet 431 may move so as to cover about half of the opening as shown by the dotted line 431 ′ without covering the entire opening. By placing the radio wave absorber sheet 431 on the side of the marker 10 where the gain of the antenna 17 is desired to be reduced, the directivity can be adjusted.

  Alternatively, a plurality of radio wave absorber sheets 431, 432, and 433 may be placed immediately below the antenna 17 of the marker 10. The transmission output from the marker 10 can be attenuated by a plurality of radio wave absorber sheets 431, 432, and 433, and the attenuation is changed by changing the thickness, number, and size of the radio wave absorber sheets (431, 432, and 433). Adjust.

 FIG. 12 is an explanatory diagram illustrating an example of a method of measuring a received signal strength (RSSI) of radio waves from the marker 10 by the mobile terminal 20. In FIG. 12A, for convenience, an example in which the marker 10 is placed on the ground and the RSSI is measured when the mobile terminal 20 is moved in a two-dimensional region in the X direction and the Y direction at a position 1.5 m from the ground. Is shown. Actually, the marker 10 is arranged on the ceiling portion. However, if the marker 10 is turned upside down in FIG. 12A, the marker 10 is located on the ceiling portion.

 As shown in FIG. 12B, the X direction extends from the center of the marker 10 in the plus (+) direction and minus (−). Similarly, the Y direction also has a plus (+) direction centered on the marker 10; It extends to minus (-). The power switch 18 side of the marker 10 corresponds to the plus (+) side in the X direction.

  FIG. 13 to FIG. 18 are distribution diagrams showing examples of measurement results of RSSI. Referring to FIG. 13 as a representative, the horizontal axis represents the X direction, and the vertical axis represents the distance (m) in the Y direction. In FIG. 13, the RSSI is measured at intervals of 1 m in the range of the two-dimensional direction (+10 m to −10 m) of the mobile terminal 20 around the position of the marker 10 (0 m of X, Y). Show. In FIG. 13, the darker color indicates that the received signal intensity is stronger, and the lighter color indicates that the received signal intensity is weaker. In addition, the narrower the reception area (cover area) indicated by the shading of the color, the narrower the directivity is.

  FIG. 13 shows the result of measuring the RSSI distribution of the marker 10 alone. In FIG. 13, in order to reduce the influence of reflection from the ground, the radio wave absorber sheet 52 (see FIG. 12) is inserted between the marker 10 and the ground. In FIG. 13, there is a possibility of erroneous detection that the reception area of the mobile terminal 20 is wide and the similar marker 10 is in the vicinity.

  FIG. 14 shows the result of measuring the RSSI distribution when the marker 10 is housed in the shield 40 formed of the metal body 42 and the radio wave absorber 43 shown in FIG. 7 and the offset amount H is zero. In FIG. 14, the reception area in the X direction and the Y direction is narrower than that in FIG.

 FIG. 15 shows the result of measuring the RSSI distribution when the marker 10 is accommodated in the shield 40 composed of the metal body 42 and the radio wave absorber 43 and the offset amount H is 10 mm. As a result of setting the offset amount to 10 mm, the reception area in FIG. 15 is narrower than that in FIG.

 FIG. 16 shows the result of measuring the RSSI distribution when the marker 10 is accommodated in the shield 40 composed of the metal body 42 and the radio wave absorber 43 and the offset amount H is 20 mm. As a result of setting the offset amount to 20 mm, the reception area in FIG. 16 is narrower than that in FIG.

 17, the marker 10 is accommodated in a shield 40 composed of a metal body 42 and a radio wave absorber 43, the offset amount H is set to 10 mm, and the upper surface of the marker 10 (the opening of the shield 40 as shown in FIG. 11). The result of having measured RSSI distribution when 41) is covered with the 10-mm-thick electromagnetic wave absorber sheet | seat 431 is shown. FIG. 15 described above also has an offset amount of 10 mm, but in FIG. 17, the reception area is narrower than those in FIGS. 15 and 16 because of the presence of the radio wave absorber sheet 431.

 18, the marker 10 is accommodated in a shield 40 composed of a metal body 42 and a radio wave absorber 43, the offset amount H is set to 20 mm, and the upper surface of the marker 10 (the opening of the shield 40 as shown in FIG. 11). The result of measuring the RSSI distribution when 41) is covered with two 10 mm-thick radio wave absorber sheets 431 and 432 is shown. FIG. 16 described above also has an offset amount of 20 mm, but since there are two radio wave absorber sheets, the reception area in FIG. 18 is narrower than that in FIGS. By covering with a radio wave absorber sheet, the transmission output per sheet can be reduced by about 3 dB.

  As can be seen from the above measurement results, the amount of attenuation of radio waves emitted from the marker 10 increases as the shield 40 is present. Moreover, the amount of attenuation increases as the offset amount H increases and the number of radio wave shielding sheets (431, 432,...) Increases, and the directivity can be narrowed down. Therefore, the directivity can be adjusted by selecting the configuration of the shield 40, the offset amount, the thickness and the number of the radio wave absorber sheets according to the situation of the room in which the marker 10 is installed. As a result, the radio wave receivable area of the mobile terminal 20 can be narrowed or widened, the emission of radio waves transmitted from the radio wave transmitter 10 in a specific direction is restricted, and the radio waves are transmitted to a preset area. can do.

  FIG. 19 is an explanatory diagram illustrating another arrangement example of the radio wave absorber sheet 431. FIG. 19 shows an example in which the radio wave absorber sheet 431 is disposed so as to be orthogonal to the longitudinal direction of the marker 10 and only the central portion of the opening 41 of the shield 40 is covered with the radio wave absorber sheet 431. FIG. 19A is a plan view, FIG. 19B is a cross-sectional view seen from the side direction, and shows an example in which the marker 10 is placed on the ground as in FIG.

 20, when the marker 10 is arranged on the ground as shown in FIG. 19, the marker 10 is accommodated in the shield 40, and the offset amount H is zero, the mobile terminal 20 is moved at a position 1.5 m from the ground. Then, the result of measuring the distribution of RSSI is shown. In FIG. 20, it can be seen that the reception area in the X and Y directions is narrower than in FIG.

 Therefore, the directivity can also be adjusted by changing the direction of the radio wave shielding sheet 431, and the radio wave receivable area of the mobile terminal 20 can be changed. Further, the radio wave absorber sheet 431 in FIG. 19 may be shifted left and right (X direction).

 FIG. 21 is an explanatory diagram showing the installation direction of the marker 10. As shown in FIG. 21, when the interval L1 between the marker 10 and the wall on the adjacent room side is narrow, the marker 10 may be installed so that the power switch 18 faces the opposite side to the adjacent room. That is, from the distribution characteristics of FIGS. 13 to 18, the coverage area of the radio wave from the marker 10 tends to shift toward the power switch 18 side (plus side) in the X direction. For this reason, if it installs so that the power switch 18 side of the marker 10 may face an adjacent room, the leak to an adjacent room can be reduced.

 FIG. 22 is an explanatory diagram showing the installation position of the marker 10. In FIG. 22, markers 10a and 10b are installed in rooms 3a and 3b, respectively, and their positions are point A and point B, respectively. Further, a point where the RSSI in the room 3a is the maximum value is set as a point C, and a point where the leak amount from the marker 10a to the adjacent room 3b is maximized is set as a point D. Further, the reception level (interference wave) from the marker 10a at the point D is Pad, and the reception level (desired wave) from the marker 10b is Pbd.

  In order to improve the ratio of the desired wave and the interference wave at point D (D / U = Pbd−Pad), (a) increase the transmission output of the marker 10b and decrease the transmission output of the marker 10a, or (b It is conceivable to increase the antenna gain of the marker 10b in the direction of the D point, decrease the antenna gain of the marker 10a in the direction of the D point, or (c) increase the attenuation between the rooms 3a and 3b. In (a), a dead zone occurs in a room with a large cover area. Moreover, in (c), since it depends on the structure of the building and the material of the wall, it cannot be taken. Therefore, (b) is an effective method.

  The antenna gain of the marker 10a and the marker 10b can be dealt with by using the shield 40 and the radio wave absorber sheet 431, changing the position and orientation of the radio wave absorber sheet 431, and adjusting the offset amount H. it can. Therefore, in the embodiment, the directivity can be arbitrarily adjusted according to the size of the room in which the marker 10 is installed, the state of the adjacent room, and the like. When a plurality of markers are installed in a large room, the directivity can be adjusted so that the radio wave cover areas from the markers do not interfere with each other.

  As described above, according to the first embodiment, the directivity characteristics of the radio wave from the marker 10 can be arbitrarily adjusted according to the installation position.

  Further, since the marker 10 only outputs weak radio waves, the power consumption is extremely low. Therefore, if the light intensity is sufficient, power can be supplied only by the solar cell 12 built in the marker 10, and an external power supply is not necessary. Even when the light intensity is not sufficient, the built-in battery 13 can be used for several years, so that the operation cost can be reduced.

  Furthermore, by installing a plurality of markers 10 so as to cover indoors and outdoors, the management server 30 can accurately acquire the current position of the mobile person holding the mobile terminal 20 and obtain an action history. be able to.

  In the first embodiment, an example in which a marker is installed in the facility 100 such as a nursing facility or a medical facility has been described. However, the marker may be installed in another facility (such as a shopping center or a department store). The management server 30 can be composed of a tablet computer or the like in addition to a personal computer. Moreover, although the example which uses Bluetooth (trademark) as a specification of near field communication was described, RFID (Radio Frequency Identification) etc. can also be used.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

10 ... Radio wave transmitter (marker)
DESCRIPTION OF SYMBOLS 11 ... BT-module 12 ... Solar cell 20 ... Portable terminal 26 ... Near field communication part 27 ... Wireless communication part (2nd wireless communication part)
DESCRIPTION OF SYMBOLS 30 ... Management server 35 ... Communication part 34 ... Display part 40 ... Shielding body 41 ... Opening part 42 ... Metal body 43 ... Radio wave absorber 431, 432, 433 ... Radio wave absorber sheet

Claims (6)

A radio wave transmitter that transmits a radio wave including its own identification information by a short-distance wireless transmission with a preset transmission cycle and transmission output, and is driven by a battery;
A shield that houses the radio wave transmitter, regulates radiation in a specific direction of radio waves transmitted from the radio wave transmitter, and transmits radio waves to a preset area;
A radio wave transmitter comprising:   The radio wave transmission device according to claim 1, wherein the shield includes a radio wave absorber capable of accommodating the radio wave transmitter, and a metal body disposed on an outer peripheral surface of the radio wave absorber.   The radio wave transmitter according to claim 2, wherein the radio wave transmitter is accommodated in the shield so as to be pulled in from the opening of the shield by a predetermined offset amount.   The radio wave transmission device according to claim 2, further comprising at least one radio wave absorber sheet disposed to face the opening of the shield. A radio wave transmitter that is installed at a plurality of locations, transmits radio waves including its own identification information by short-range wireless transmission, and has a variable transmission cycle and transmission output. A radio wave transmission device whose directivity is adjusted so as to restrict radiation and transmit radio waves to a preset area;
A short-range wireless communication unit that receives radio waves from the radio wave transmission device; and a second wireless communication unit that transmits and receives information; and the identification information of the radio waves received by the short-range wireless communication unit and the received electric field strength A portable terminal that transmits information from the second wireless communication unit;
Management that communicates with the second wireless communication unit, determines the position of the mobile terminal based on the identification information and the received electric field strength information transmitted from the mobile terminal, and displays the current position of the mobile terminal A position measurement system comprising a server.   The position measurement system according to claim 5, wherein the radio wave transmission device includes a shield that adjusts directivity so that radio waves are transmitted from the radio wave transmitter to the predetermined region.