JPWO2018193726A1 - Signal transmission device, signal transmission system, transmission module arrangement method, and transmission module usage method - Google Patents

Abstract

A signal transmitting device used for measuring a position of a signal receiving device is provided. The signal transmission device includes a housing having an opening, and a transmission module mounted in the housing and periodically transmitting a transmission signal including identification information of the signal transmission device. Part or all of the inner surface of the housing is formed of a conductive material. The longest distance from the transmitting module to the conductive material is at least half the wavelength of the transmitted signal.

Description

  This international application claims the priority based on Japanese Patent Application No. 2017-082756 filed with the Japan Patent Office on April 19, 2017, and discloses the priority of Japanese Patent Application No. 2017-082756. The entire contents are incorporated by reference into this international application.

  The present disclosure relates to a signal transmission device, a signal transmission system, a method of arranging a transmission module, and a method of using the transmission module, and particularly to a signal transmission device and a signal used for measuring a position of a mobile body having a signal reception device The present invention relates to a transmission system, a method of arranging a transmission module, and a method of using the transmission module.

  2. Description of the Related Art Conventionally, as a method of performing near field communication, a technique is known in which a beacon device transmits a beacon signal and a communication terminal receives the beacon signal.

  For example, JP-A-2006-24606 (Patent Document 1) discloses a beacon signal transmitting device. The beacon signal transmitting device includes a transmitting module that periodically transmits an advertisement signal defined by the Bluetooth (registered trademark) standard as a beacon signal, and a housing that houses the transmitting module. Then, a conductive layer is formed on at least a portion of the inner surface of the housing facing the transmission module.

JP-A-2006-24606

  By the way, in recent years, there is a technique for estimating the current position of a terminal based on the radio wave intensity received from a transmitter of a plurality of beacon signals installed in a space. In the positioning technology using the received radio wave intensity of the beacon signal, there is a problem that an error occurs in the estimated current position due to fading such as reflection (multipath) and interference, so that the effect of fading is suppressed. Is required. The technique of Patent Document 1 is studying suppression of the transmission output of the beacon signal transmitted by the beacon signal transmission device with a simple configuration, but does not teach or suggest any technical means that satisfies the above needs. Absent.

  An object of the present disclosure, in one aspect, is to provide a signal transmission device, a signal transmission system, a method of arranging a transmission module, and a method of using the transmission module that can suppress fading with a simple configuration.

  According to one embodiment, there is provided a signal emitting device used for measuring a position of a signal receiving device. The signal transmission device includes a housing having an opening, and a transmission module attached to the housing and periodically transmitting a transmission signal including identification information of the signal transmission device. Part or all of the inner surface of the housing is formed of a conductive material. The longest distance from the transmitting module to the conductive material is 以上 or more of the wavelength of the transmitted signal.

  According to the present disclosure, fading can be suppressed with a simple configuration.

FIG. 2 is a schematic diagram showing an appearance of the signal transmission device according to the first embodiment. FIG. 2 is a plan view of the signal transmission device when viewed from the direction of arrow II in FIG. 1. FIG. 3 is a schematic sectional view taken along a line III-III shown in FIG. 2. FIG. 4 is a schematic sectional view taken along the line IV-IV shown in FIG. 2. FIG. 3 shows a state where the signal transmission device according to the first embodiment is installed on a ceiling. FIG. 3 shows a state where the signal transmission device according to the first embodiment is installed on a ceiling. FIG. 5 is a plan view of a signal transmission device according to a first modification of the first embodiment. FIG. 8 is a schematic sectional view taken along line VIII-VIII shown in FIG. 7. FIG. 7 is a schematic diagram showing an appearance of a signal transmission device according to a second modification of the first embodiment. FIG. 14 is a schematic diagram showing an appearance of a signal transmission device according to a third modification of the first embodiment. FIG. 11 is a diagram for illustrating a signal transmitting device according to a second embodiment. FIG. 11 is a diagram for illustrating a signal transmitting device according to a second embodiment. FIG. 13 is a schematic diagram showing an appearance of a signal transmission device according to a third embodiment. FIG. 13 is a schematic sectional view of a signal transmission device according to a third embodiment. FIG. 14 is a diagram showing an overall configuration of a signal transmission system according to a fourth embodiment. It is a figure which shows the relationship of the height and space | interval for suppressing a position measurement error.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed description thereof will not be repeated.

  The signal transmission device according to the present embodiment is used for a position measurement system for measuring the current position of a mobile object (for example, a person) indoors or outdoors. For example, in a position measurement system, signal transmission devices are installed at a plurality of positions in a facility, and a signal reception device (for example, a mobile terminal device) capable of receiving a transmission signal (for example, a beacon signal) from each signal transmission device. ) Is carried by the mobile.

  The mobile terminal device receives the beacon signal from the signal transmission device, and acquires identification information (beacon ID) of the signal transmission device included in the beacon signal. By transmitting the beacon ID to the server, the mobile terminal device queries the server for beacon position information corresponding to the beacon ID. The mobile terminal device measures the current location information of the own device (position information of the current location) based on the inquiry result from the server. A signal transmission device used in such a position measurement system will be specifically described.

[Embodiment 1]
FIG. 1 is a schematic diagram showing an appearance of signal transmission device 100 according to the first embodiment. FIG. 2 is a plan view of the signal transmission device 100 when viewed from the direction of arrow II in FIG. FIG. 3 is a schematic cross-sectional view along the line III-III shown in FIG. FIG. 4 is a schematic sectional view taken along line IV-IV shown in FIG.

  Signal transmitting device 100 according to the first embodiment includes a small transmitting module (for example, a transmitting-side beacon module) 20 having a transmitting circuit built therein, and a casing 10 for housing the transmitting module. A battery (not shown) as a drive source of the transmission module 20 is housed in the housing 10.

  The transmission circuit converts a transmission signal including the identification information (beacon ID) of the signal transmission device 100 into a radio wave (for example, a 2.4 GHz band radio wave) around the signal transmission device 100 for a predetermined period (for example, 0.1 second). To send. The portable terminal device carried by the mobile receives the transmission signal. The communication standard used between the signal transmission device 100 and the portable terminal device is, for example, a short-range wireless communication standard such as Bluetooth (registered trademark) or BLE (Bluetooth Low Energy). For example, the signal transmission device 100 corresponding to the BLE standard transmits the advertising data including the beacon ID as a transmission signal to the periphery of the signal transmission device 100 by broadcast.

  The housing 10 has a substantially rectangular parallelepiped shape, and is made of at least a conductive material. For example, the housing 10 is made of a metal material. The housing 10 has an opening 14, an upper surface 12 facing the opening 14, and side surfaces 16 surrounding the upper surface 12. The side surface 16 extends downward from the edge of the upper surface 12. The side surface 16 and the upper surface 12 have at least portions where the conductive material is exposed. The conductive material is not particularly limited as long as it is a material used for conducting electricity, and examples thereof include aluminum, silver, copper, and nickel.

  The opening 14 is a rectangular opening having a width dimension (width dimension) W and a depth dimension (depth dimension) D. The width dimension W and the depth dimension D may be the same or different.

  The transmission module 20 is mounted in the housing 10. Typically, the transmitting module 20 is fixed to the inner surface of the housing 10 with an adhesive, a screw, a double-sided tape, or the like. In the examples of FIGS. 2 to 4, the transmission module 20 is attached inside one of the four side surfaces of the housing 10 (solid line portion in FIG. 2). In addition, the transmission module 20 may be attached inside the other side surface of the housing 10 (a broken line portion in FIG. 2).

  The height H of the internal space of the housing 10 corresponds to the length between the surface on which the opening 14 is provided (opening surface) and the inside 15 of the upper surface 12. In addition, the width dimension and the depth dimension of the internal space of the housing 10 correspond to the width dimension W and the depth dimension D of the opening 14, respectively. Note that typically, the thickness Th of the housing 10 is so small as to be negligible compared to the width dimension W, the depth dimension D, and the height dimension H, respectively.

  The longest distance L from the transmitting module 20 to the conductive material formed on the inner surface of the housing 10 is defined as follows. Specifically, when a concentric circle is drawn while increasing the radius around the transmitting module 20, the radii of a plurality of concentric circles where (the position of) the conductive material exists on the circumference are specified. The longest distance L corresponds to the largest radius of the plurality of concentric circles. In the examples of FIGS. 1 and 4, since the entire inner surface of the housing 10 is made of a conductive material, the longest distance L is equal to the distance from the center of the transmitting module 20 to the corner 17 in the housing 10. Become.

  The signal transmission device 100 as described above is installed on a ceiling, a wall, or the like. Embodiment 1 describes a configuration in which signal transmission device 100 is installed on a ceiling.

  FIGS. 5 and 6 show a state where signal transmission device 100 according to the first embodiment is installed on ceiling 50. Specifically, FIG. 5 is a schematic cross-sectional view corresponding to FIG. 3 when the upper surface 12 of the housing 10 is attached to the ceiling 50. FIG. 6 is a schematic cross-sectional view corresponding to FIG. 4 when the upper surface 12 of the housing 10 is attached to the ceiling 50.

  Referring to FIGS. 5 and 6, the outside of upper surface 12 facing opening 14 of housing 10 is attached to ceiling 50. The housing 10 is fixed to the ceiling 50 by, for example, screws.

  The arrows in FIGS. 5 and 6 schematically show how the transmission signal transmitted from the transmission module 20 propagates from the opening 14 to the outside of the housing 10 while being reflected inside the housing 10. The center frequency of a radio wave (transmission signal) transmitted from the transmission module 20 is 2.4 GHz, which is a microwave. Therefore, the transmitted signal is reflected by the inner surface of the housing 10 formed of a conductive material.

  Thus, the radio wave transmitted from the transmission module 20 directly reaches the opening 14, the radio wave reflected on the inner surface of the housing 10, and the radio wave reflected on the inner surface of the housing 10 is reflected again on the inner surface. It reaches the opening 14 from various directions, such as one that reaches the opening 14. That is, since these radio waves have different path lengths to reach the opening 14, the radio waves emitted from the opening 14 have a phase shift.

  Here, fading in radio wave transmission means that radio waves cancel each other at a point where the phase of the radio wave directly reaching the receiving terminal (signal receiving device) of the radio wave and the phase of the radio wave arriving after being reflected on the floor or the like deviate by π. This causes the radio wave intensity to become extremely small.

  In the present embodiment, radio waves having various phases are transmitted from the housing 10 by reflecting the radio waves in the housing 10. Therefore, in the process of propagating radio waves, even if radio waves having phases shifted by π may cancel each other, the radio field intensity does not become extremely small only at a specific location, and thus fading is suppressed.

  Also, conventionally, when the signal strength of a radio wave shows a finite value to a distant place, the signal receiving device continues to receive signals from a plurality of signal transmitting devices, and the distance from the signal transmitting device to the signal receiving device cannot be accurately measured. There was also. However, in the present embodiment, the radio waves cancel each other little by little in the process of transmitting the radio waves, so that the attenuation of the radio wave intensity due to the increase in the distance becomes faster than in the case where the housing 10 is not present. Therefore, the signal receiving device can easily receive the signal of the nearest signal transmitting device 100, and can accurately measure the distance from the signal transmitting device 100 to the signal receiving device.

  Further, in order to suppress fading, the longest distance L from the transmission module 20 to the conductive material needs to be １ ／ or more of the wavelength of the transmission signal. For example, when the transmission module 20 is a beacon module and the frequency of the transmission signal is in the 2.4 GHz band, L is preferably 6.2 cm or more.

  As described above, in the present embodiment, the radio waves of various phases are emitted from the opening 14 to suppress the radio wave intensity from extremely lowering (fading) at a specific position. Therefore, even if a radio wave is reflected by installing a conductive layer material in the direction of gravity and transmitting radio waves without installing a conductive material in the horizontal direction, radio waves with different propagation path lengths overlap, and Fading that reduces the strength is suppressed. In other words, when the longest distance L is less than 波長 of the wavelength of the transmitting module, the difference in the propagation path lengths of a plurality of radio waves cannot be increased and the facing cannot be sufficiently suppressed.

  In order to suppress fading, it is preferable that the width dimension W or the depth dimension D of the internal space and the height dimension H are different. This is for the following reasons.

  Specifically, from the viewpoint of transmitting radio waves of various phases, a large number of distances between the transmitting module 20 and the reflection positions of the radio waves transmitted from the transmitting module 20 may be sufficient. However, when the transmitting module 20 is mounted on the housing having the same width dimension W or depth dimension D and the same height dimension H, the number of radio waves having the same distance increases, and the phase shift of the radio waves decreases. . Therefore, the housing 10 in which the width dimension W or the depth dimension D of the internal space is different from the height dimension H is preferable.

  Further, it is preferable that the longest distance L is not more than three times the wavelength of the transmission signal transmitted from the transmission module 20. For example, when the transmitting module 20 is a beacon module and transmits radio waves in a frequency band of 2.4 GHz, L is preferably 37.5 cm or less. This is because, when the longest distance L exceeds three times, the convergence of the signal transmitted from the signal transmission device 100 increases, and the area in which the signal reception device (for example, a mobile terminal device) can receive is narrowed. In other words, by controlling the longest distance L to be equal to or less than three times the wavelength of the transmitted signal, the area in which the signal receiving device carried by the mobile body can receive the transmitted signal transmitted from the signal transmitting device 100 can be widened. Thus, the number of signal transmission devices 100 can be reduced.

<Modified example of mounting position of transmitting module 20>
FIG. 7 is a plan view of signal transmission device 100A according to the first modification of the first embodiment. FIG. 8 is a schematic cross-sectional view along the line VIII-VIII shown in FIG.

  In the example of FIG. 2, the configuration in which the transmission module 20 is attached to the inside of the side surface of the housing 10 has been described. As shown in FIGS. 7 and 8, the transmission module 20 may be configured to be attached to the inside 15 of the upper surface 12 of the housing 10. The transmitting module 20 is fixed to the inner side 15 of the upper surface 12 by an adhesive, a screw, a double-sided tape, or the like. Note that the longest distance L from the transmission module 20 to the conductive material is not less than １ ／ and not more than 3 times the wavelength of the transmission signal.

<Modified example of shape of housing 10>
FIG. 9 is a schematic diagram showing an appearance of signal transmission device 100B according to the second modification of the first embodiment. FIG. 10 is a schematic diagram showing an appearance of a signal transmission device 100C according to a third modification of the first embodiment.

  In the signal transmission device 100 according to the first embodiment, the case has been described in which housing 10 for housing transmission module 20 has a substantially rectangular parallelepiped shape, but has a shape as shown in FIGS. 9 and 10. It may be.

  Referring to FIG. 9, signal transmission device 100 </ b> B has a substantially quadrangular pyramid shape, and includes a housing 30 for housing transmission module 20. For example, the housing 30 is made of a metal material. The housing 30 has an opening 34, an upper surface 32 facing the opening 34, and side surfaces 36 surrounding the upper surface 32. The side surface 36 extends downward from the edge of the upper surface 32. The longest distance L from the transmission module 20 to the conductive material is not less than 波長 and not more than 3 times the wavelength of the transmission signal.

  Referring to FIG. 10, signal transmission device 100 </ b> C has a substantially cylindrical shape, and includes a housing 40 for housing transmission module 20. For example, the housing 40 is made of a metal material. The housing 40 has an opening 44, an upper surface 42 facing the opening 44, and a side surface 46 surrounding the upper surface 42. The side surface 46 extends downward from the edge of the upper surface 42. The longest distance L from the transmission module 20 to the conductive material is not less than 波長 and not more than 3 times the wavelength of the transmission signal.

<Advantages>
According to the first embodiment, it is possible to improve the accuracy of position measurement by suppressing fading with a simple method. In addition, with a smaller number of signal transmission devices 100, the reception area of transmission signals that can be received by the signal reception device can be made as large as possible.

[Embodiment 2]
In the second embodiment, a configuration in which a light source for illumination is accommodated in a housing 10 will be described. In the second embodiment, a configuration in which a solar cell is used as a power supply for supplying power to transmission module 20 will be described. FIG. 11 and FIG. 12 are diagrams for illustrating the signal transmitting device according to the second embodiment.

  Referring to FIG. 11, signal transmitting device 100D according to the second embodiment further includes a solar cell 73 and a light source 90 in addition to housing 10 and transmitting module 20.

  The solar cell 73 is mounted in the housing 10 similarly to the transmission module 20. In the example of FIG. 11, the solar cell 73 is mounted on the same surface as the surface on which the transmitting module 20 is mounted. However, the solar cell 73 does not necessarily need to be mounted on the same surface, but only needs to be mounted in the housing 10 and at a position that can receive light emitted from the light source 90.

  The solar cell 73 and the transmission module 20 are connected via a wiring member (not shown). Thus, the transmission module 20 can receive the light from the light source 90 and receive the power generated by the solar cell 73. The type of the solar cell 73 may be appropriately selected depending on the illuminance of the light source 90 and the like. For example, when using an LED (light emitting diode) as the light source 90, it is preferable to use a dye-sensitized solar cell (DSC).

  Typically, the light source 90 is a downlight light source embedded in the ceiling 50. As shown in FIG. 12, signal transmission device 100E according to the modification of the second embodiment further includes a fluorescent lamp 92 in addition to housing 18 and transmission module 20 made of a conductive material.

  According to the second embodiment, the signal transmission device can use both the function of transmitting a beacon signal and the function of lighting. In addition, while the light source 90 irradiates the solar cell 73 with light, the transmission module 20 can continuously transmit a transmission signal semipermanently. Further, since the light of the light source 90 is reflected on the inner surface formed of the conductive material and the scattered light is evenly applied to the light receiving surface of the solar cell 73, stable power supply to the transmitting module 20 can be realized.

[Embodiment 3]
In the third embodiment, another configuration using a solar cell as a power supply for supplying power to transmission module 20 will be described. FIG. 13 is a schematic diagram showing an appearance of signal transmitting device 100F according to the third embodiment. FIG. 14 is a schematic sectional view of signal transmission device 100F according to the third embodiment.

  Referring to FIG. 13 and FIG. 14, signal transmission device 100 </ b> F includes housing 11, transmission module 20, and solar cell 71. The signal transmission device 100F is fixed to a telephone pole via a band, for example. Arrows in FIG. 13 indicate propagation of radio waves (transmission signals) transmitted from the transmission module 20.

  The cell substrate 70 of the solar cell 71 and the transmission module 20 are connected via a wiring member 80. Thereby, transmission module 20 can receive the supply of the power generated by solar cell 71.

  The solar cell 71 is attached to an outer surface of the housing 11. Specifically, the solar cell 71 is attached to the outside 23 on the upper surface of the housing 11. A through-hole 83 is formed in the upper surface of the housing 11 so as to penetrate in the thickness direction of the upper surface. The configuration of the housing 11 other than the through hole 83 is the same as the configuration of the housing 10. The through-hole 83 is, for example, a hole through which a wiring member 80 for electrically connecting the transmitting module 20 and the cell substrate 70 passes. Typically, since the through-hole 83 is covered by the transmitting module 20, the through-hole 83 is configured to be invisible from the opening 14.

  The light receiving surface 72 of the solar cell 71 is provided on the side of the solar cell 71 opposite to the surface 74 to which the housing 11 is attached. The solar cell 71 is, for example, an amorphous silicon solar cell or a DSC. The solar cell 71 may be attached to the outer surface of the housing 11, for example, may be attached to the outside of the side surface of the housing 11.

  According to the third embodiment, while the solar cell 71 is irradiated with light, the transmission module 20 can continue transmitting the transmission signal semipermanently.

[Embodiment 4]
In Embodiment 4, a method for installing a plurality of signal transmission devices 100 will be described. FIG. 15 shows an overall configuration of a signal transmission system 1000 according to the fourth embodiment. The signal transmission system 1000 is a system for measuring the position of a mobile object having a receiving device capable of receiving a transmission signal in a predetermined building (for example, a commercial facility, an office, an airport, a hospital, a nursing facility, and the like). is there. Here, it is assumed that a mobile object has a portable terminal device 200 as a receiving device.

  In the signal transmission system 1000, a plurality of signal transmission devices 100 are installed at a position at a height K from a plane 300 on which a moving object moves. Further, the plurality of signal transmission devices 100 are provided at intervals I. For example, the signal transmission device 100 is embedded in a ceiling.

  The mobile terminal device 200 receives a transmission signal from one or a plurality of signal transmission devices 100 within an effective reach of the plurality of signal transmission devices 100. The mobile terminal device 200 decodes the beacon ID from the received transmission signal and calculates the radio field intensity of the transmission signal. The radio wave intensity is correlated with the distance between the portable terminal device 200 and the signal transmission device 100, and the higher the radio wave intensity, the shorter the distance. The portable terminal device 200 executes the above process each time the transmission signal is received.

  The mobile terminal device 200 transmits the beacon ID to a server (not shown). The server receives the beacon ID from the mobile terminal device 200, and acquires beacon position information (for example, coordinate data) corresponding to the received beacon ID with reference to a predetermined table. The server transmits the beacon position information to the mobile terminal device 200. The mobile terminal device 200 calculates its own current location information (current location coordinate data) based on the received beacon position information and the received radio wave intensity.

  In order for the mobile terminal device 200 to accurately calculate the position information of the own device, the signal transmission devices 100 need to be arranged at appropriate intervals. For example, if the distance between the signal transmitting devices 100 is too wide, the moving object may be located at a middle point on both sides of the signal transmitting device 100, so that the position of the moving object cannot be calculated accurately.

  Here, the signal transmission device 100 has a configuration in which the transmission module 20 is housed in the housing 10, and the transmission signal is transmitted from the opening 14 of the housing 10. Therefore, the directivity of the transmitted signal when the transmitting module 20 is housed in the housing 10 is higher than the directivity of the transmitted signal when the transmitting module 20 is not housed in the housing 10. Therefore, the transmittable area of the transmission signal transmitted from the signal transmission device 100 needs to cover a desired area in the plane 300 on which the mobile body moves.

  FIG. 16 is a diagram showing the relationship between the height K and the interval I for suppressing the position measurement error. Specifically, FIG. 16 shows the relationship between the height K and the interval I when the position measurement error is 2 m.

The data in FIG. 16 was obtained by the following procedures (a1) to (a6).
(A1) A plurality of stretching rods capable of changing the height K are prepared, and a transmitting module 20 is attached to the tip of the stretching rod so that the opening of the signal transmitting device is vertically downward, and the stretching rods are arranged at arbitrary intervals. Install vertically.

  (A2) The mobile terminal device 200 measures the signal strength (radio wave strength) of each transmitting module 20 (beacon module) while keeping the height K constant and changing the interval I. Note that the signal strength of each transmitting module 20 is an average value during (signal transmitting interval × 20 seconds).

  (A3) The top three signals are selected from the signal intensities, and the distance d from the portable terminal device 200 to the signal transmission device 100 is calculated for each of the selected signal intensities according to the following equation (1). λ is the wavelength of the transmitted signal.

Signal strength P = A (λ / 4πd) 2 (1)
A is corrected from the signal strength when the linear distance is known.

  (A4) The positions of the three transmitting modules 20 are (x1, y1), (x2, y2), (x3, y3), and the distance (d1) between the three portable terminal devices 200 and the transmitting module 20 calculated from the signal strengths , D2, d3) (where d1> d2> d3). Then, the simultaneous equations of the following equations (2) and (3) are solved to obtain two solutions (α, β) and (γ, δ).

(Xx-2) 2+ (yy-2) 2 = d22 (2)
(Xx3) 2+ (yy3) 2 = d32 (3)
The obtained two solutions are substituted as in the following equation (4), and the smaller value of the right side and the left side is defined as a solution (measured value). Equation (4) is a case where the left side is small.

| (Α-x1) 2+ (β-y1) 2-d12 | <| (γ-x1) 2+ (δ-y1) 2-d12 | (4)
(A5) Since the actual position (α0, β0) of the terminal is found by actual measurement, the measurement error Δ is calculated by the following equation (5).

Δ = ((α−α0) 2+ (β−β0) 2) 1/2 <2 (m) (5)
(A6) Then, the height K is changed, the measurement error Δ is calculated in the same manner, and the values of K and I that result in a measurement error of 2 m are plotted to obtain FIG.

  Referring to FIG. 16, curve 600 shows a line at which the position measurement error is 2 m. The upper region Xa of the curve 600 is a region where the position measurement error is 2 m or more, and the lower region Xb of the curve 600 is a region where the position measurement error is less than 2 m. Therefore, in order to reduce the position measurement error, it is understood that the interval I needs to be reduced as the height K decreases. For example, since the curve 600 is represented by K = 2 + 0.3I2, it is necessary to adjust the height K and the interval I so as to satisfy K <2 + 0.3I2 to make the position measurement error less than 2 m.

<Advantages>
According to the fourth embodiment, since a plurality of signal transmission devices 100 are provided at appropriate intervals according to the installation height, a position measurement error of portable terminal device 200 can be reduced.

[Embodiment 5]
In the above-described embodiment, the case where the housing is made of a conductive material has been described. However, the present invention is not limited to this configuration. Only a part of the upper surface or only a part of the side surface) or the whole may be formed of a conductive material. For example, a case where a conductive layer made of a conductive material uniformly applied by a spray gun, for example, may be formed on the inner surface of the housing 10.

Embodiment 6
In the sixth embodiment, a description will be given of a method of arranging transmitting module 20 in an existing specific space and a method of using transmitting module 20. Specifically, the transmission module 20 is in a space having an opening (for example, in the housing 10) in which a part or the whole of the inner surface is formed of a conductive material. It is sufficient that the longest distance L is located at a position of not less than 1/2 and not more than 3 times the wavelength of the transmission signal.

  Further, the transmitting module 20 is mounted in a space having an opening in which a part or the whole of the inner surface is formed of a conductive material, and the wavelength of the transmitting module 20 is 1/3 to 2 times the longest distance L. It may be used as it is.

[Other embodiments]
The configuration illustrated as the above-described embodiment is an example of the configuration of the present disclosure, and can be combined with another known technology, and a part is omitted without departing from the gist of the present disclosure. It is also possible to change and configure.

  Further, in the above-described embodiment, a case may be adopted in which the processes and configurations described in the modified examples and other embodiments are appropriately combined and executed.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present disclosure is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 11, 18, 30, 40 housing, 12, 32, 42 top surface, 14, 34, 44 opening, 16, 36, 46 side surface, 20 transmission module, 50 ceiling, 70 cell substrate, 71, 73 solar cell , 72 light receiving surface, 80 wiring member, 83 through hole, 90 light source, 92 fluorescent lamp, 100, 100A-100F signal transmission device, 200 portable terminal device, 300 plane, 600 curve, 1000 signal transmission system.

Claims (10)

A signal transmitting device used to measure the position of the signal receiving device,
A housing having an opening;
A transmission module attached to the housing and periodically transmitting a transmission signal including identification information of the signal transmission device,
Part or all of the inner surface of the housing is formed of a conductive material,
A signal transmission device, wherein a longest distance from the transmission module to the conductive material is equal to or more than の of a wavelength of the transmission signal.   The signal transmission device according to claim 1, wherein the longest distance is equal to or less than three times a wavelength of the transmission signal.   The signal transmission device according to claim 1, further comprising a light source attached to an inner surface of the housing. Further comprising a power supply for supplying power to the transmission module,
The signal transmission device according to claim 1, wherein the power supply includes a solar cell. The solar cell is attached to an outer surface of the housing,
The signal transmission device according to claim 4, wherein a light receiving surface of the solar cell is provided on a side of the solar cell opposite to a surface on which the housing is mounted. The solar cell is mounted in the housing,
The signal transmission device according to claim 4, wherein the solar cell receives light from the light source.   The signal transmission device according to claim 4, wherein the solar cell is a dye-sensitized solar cell. A signal transmission system comprising a plurality of the signal transmission devices according to any one of claims 1 to 7,
The plurality of signal transmission devices are provided at predetermined intervals at a predetermined height from a plane on which a moving body having the signal reception device that receives the transmission signal moves,
The signal transmission system, wherein the predetermined interval is smaller as the predetermined height is lower. A method for arranging a transmission module that periodically transmits a transmission signal,
The transmission module is a space having an opening in which a part or the whole of the inner surface is formed of a conductive material, and a longest distance from the transmission module to the conductive material is one of the wavelengths of the transmission signal. A method for arranging a transmission module, which is arranged at a position of at least / 2 and at most 3 times. A method of using a transmission module for periodically transmitting a transmission signal,
The transmitting module is mounted in a space having an opening in which a part or the whole of an inner surface is formed of a conductive material, and a wavelength of the transmitting module is a surface on which the conductive material is formed from the transmitting module. A method of using the transmitting module, which is used so as to be 1/3 to 2 times the longest distance to the transmission module.

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