Transmitter and transmission / reception system

Abstract

To enable stable positioning of transmitters that move with people or objects and transmit signals for position detection. [Solution] The three-dimensional housing on which the transmitting circuit board 141 and the transmitting antenna 142 are mounted has a fluid moving layer 13 around the mechanism mounting section 14. A fluid Fd having the characteristic (function) of attenuating signals is injected into the fluid moving layer 13. The fluid Fd is injected in such a way that it forms an attenuating section 131 that covers more than the lower half in the direction of gravity of the mechanism mounting section 14, and an unattenuating section 132 that does not cover the upper side. Since the fluid Fd moves from high to low within the fluid moving layer 13, even if the three-dimensional housing on which the transmitting circuit board 141 and the transmitting antenna 142 are mounted rotates, the unattenuating section 132 is always formed on the upper side.

Description

Technical Field

[0001] This invention relates to a transmitter and a transmission / reception system for realizing the tracking of the positions of people and objects, mainly indoors such as in facilities and factories.

Background Art

[0002] Indoor positioning technology is used in various scenarios. For example, in a company office, it is possible to grasp the whereabouts of the person in charge and quickly transfer calls, etc. In a factory or construction site, it is possible to grasp the whereabouts of workers and prevent them from entering dangerous areas. Also, in a large-scale event venue, it is possible to grasp the whereabouts of guides and security guards and flexibly change the arrangement of guides and security guards according to the congestion situation.

[0003] Patent Document 1 described later discloses an invention related to an indoor positioning device and an indoor positioning system that do not interfere with construction at a construction site. Specifically, the indoor positioning device disclosed in Patent Document 1 includes a first wireless communication function, a second wireless communication function, and a lighting function. The first wireless communication function is used for positioning indoors. The second wireless communication function communicates with other devices. Also, the indoor positioning device is an integrated lighting type installed on the ceiling. Thus, the indoor positioning device disclosed in Patent Document 1 is installed on the ceiling and can receive a transmission signal from an indoor positioning terminal held by a worker from a high place and measure the position of the indoor positioning terminal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When indoor positioning technology is used in places like company offices, metal objects that reflect radio waves are often used on doors, shelves, desks, etc. In such environments, using indoor positioning technology that determines the transmitter's position based on the receiving angle of the transmitted signal, such as AoA (Angle of Arrival) technology, can result in unstable positioning accuracy due to the influence of radio wave reflection (reflected waves) from metal objects. If the transmitter is installed in a fixed position, this can be addressed by installing the receiver while taking radio wave reflection into consideration. However, when trying to determine the position of moving people or objects, simply considering the receiver's installation position is insufficient because the direction of reflection cannot be predicted for dynamically moving objects.

[0006] As disclosed in Patent Document 1 mentioned above, indoor positioning equipment that receives transmission signals from indoor positioning terminals (transmitters) is installed on ceilings or other locations higher than the height at which the indoor positioning terminals are located (used), so there are few obstacles that directly block the transmission signals. However, in locations where the transmission signals from the indoor positioning terminals are reflected by surrounding metal products, etc., resulting in many reflected waves, it becomes as if reflected waves are arriving from all directions, and the accuracy of determining the position of the indoor positioning terminals (transmitters) becomes unstable due to the influence of these reflected waves. This can also occur in factories and construction sites where there are many metal products or metallic materials that reflect radio waves.

[0007] In view of the above, the purpose of this invention is to enable stable position determination of a transmitter that moves with people or objects and transmits position detection signals, even in locations where there are many reflected waves due to the influence of surrounding metal products, etc. [Means for solving the problem]

[0008] To solve the above problem, the transmitter of the invention described in claim 1 is: A transmitter comprising a transmitting circuit board section that forms a transmission signal and a transmitting antenna section that sends out the transmission signal, mounted in a three-dimensional housing, The aforementioned three-dimensional enclosure is A fluid transfer layer is formed by separating an externally exposed surface from an internal wall surface facing the inside of the externally exposed surface by a predetermined distance. A mechanism mounting section is provided inside the fluid moving layer, on which the transmitting circuit board and the transmitting antenna are mounted. Equipped with, The fluid moving layer is infused with a fluid having signal-attenuating properties, such that it has an attenuation section that covers more than the lower half in the direction of gravity of the mechanism mounting section, and a non-attenuation section that does not cover the upper half. It is characterized by the following:

[0009] According to the transmitter of the invention described in claim 1, the transmitter is configured such that a transmitting circuit board and a transmitting antenna are mounted in a three-dimensional housing. The three-dimensional housing is configured such that a fluid moving layer is provided around the mechanism mounting part. A fluid having the characteristic (function) of attenuating signals is injected into the fluid moving layer. In this case, the fluid is not injected completely into the fluid moving layer, and an attenuating part is provided that covers more than the lower half in the direction of gravity of the mechanism mounting part, and an unattenuated part is provided that does not cover the upper part. Since the fluid moves from high to low due to its own weight inside the fluid moving layer, an unattenuated part is always formed on the upper side even when the three-dimensional housing on which the transmitting circuit board and transmitting antenna are mounted rotates.

[0010] As a result, even if the transmitter is tilted, the fluid in the fluid moving layer will always cover more than the lower half of the mechanism mounting area, forming an attenuation zone, while leaving the upper part uncovered and forming an unattenuated zone. Therefore, the transmitted signal passing through the attenuation zone is attenuated, and even if it is reflected by metal products or other objects and becomes a reflected wave, the signal level (RSSI (Received Signal Strength Indicator)) will be reduced because it has been attenuated. In contrast, the transmitted signal passing through the unattenuated zone above the mechanism mounting area is received by the receiver without attenuation. As a result, the signal level of the reflected wave will not increase, and positioning can be performed appropriately without reducing the accuracy of determining the transmitter's position. RSSI is a value that indicates the strength of the signal that has reached the receiver, and is also called the received signal strength. [Effects of the Invention]

[0011] According to this invention, even in locations where there are many reflected waves due to the influence of surrounding metal products, the position of a transmitter that moves with people or objects and transmits position detection signals can be stably determined. [Brief explanation of the drawing]

[0012] [Figure 1] This figure illustrates the usage environment of a transmission and reception system configured to apply one embodiment of the transmitter and transmission / reception system according to this invention. [Figure 2] This is a diagram illustrating an example of the structural configuration of the transmitter according to the embodiment. [Figure 3] This is a block diagram illustrating an example of the functional configuration of the transmitter according to the embodiment. [Figure 4] This figure illustrates an example of the format of a transmission signal sent from the transmitter of the embodiment. [Figure 5] This is a block diagram illustrating an example of the receiver configuration of the embodiment. [Figure 6] This is a diagram illustrating an example of position detection information formed by the receiver of the embodiment. [Figure 7] This diagram illustrates the process of determining the position of the transmitter performed by the receiver of the embodiment. [Figure 8] This is a diagram illustrating another example of the transmitter of the embodiment. [Figure 9] This is a diagram illustrating another example of the transmitter of the embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, an embodiment of a transmitter and a transmission / reception system according to this invention will be described with reference to the drawings. In the embodiment described below, the case of constructing a transmission / reception system for positioning the current position of a transmitter in a company office will be described as an example. That is, the transmission / reception system described below is an indoor positioning system for positioning the current position of a transmitter indoors, and an embodiment of the transmitter and the transmission / reception system according to this invention is applied thereto.

[0014] [Usage environment of the transmission / reception system] FIG. 1 is a diagram for explaining the usage environment of a transmission / reception system configured by applying an embodiment of a transmitter and a transmission / reception system according to this invention, and shows a part of a company office. Generally, in a company office, furniture made of iron (steel) is often used in consideration of durability and functionality. In the case of the example shown in FIG. 1, an iron locker with a door on the left side is located, and a desk with an iron top plate and an iron panel are arranged in front of the desk.

[0015] In FIG. 1, near the desk and the panel, there is a transmitter 1 in the form of a spherical body with a diameter of about 2 to 3 cm (centimeters). The transmitter 1 is carried and functioned by a user. Specifically, the transmitter 1 can be held in the user's hand, put into the pocket of clothes, or, like a so-called strap, attached with a string-like hanging part and a clip part to the transmitter 1 and hung on the user's clothes for use. In FIG. 1, for simplicity of explanation, the illustration of the user holding the transmitter 1 is omitted.

[0016] Also, in FIG. 1, a receiver 2 is installed on the right side of the ceiling of the office. The receiver 2 receives the transmission signal from the transmitter 1 with a plurality of receiving antennas it has, and by using the so-called AoA technology, the current position of the transmitter 1 can be accurately measured. As described above, since the transmitter 1 is held by the user, being able to grasp the current position of the transmitter 1 means that the current position of the user holding the transmitter 1 can be grasped.

[0017] However, as shown in FIG. 1, the transmission signal transmitted from the transmitter 1 is radiated from the transmission antenna in various directions. Therefore, the transmission signal transmitted from the transmitter 1 is reflected on the surfaces of surrounding iron furniture and the like and reaches the receiver 2 from various directions. In such a case, due to the influence of the reflected wave, it is impossible to distinguish between the transmission signal from a certain direction of the transmitter 1 and the reflected wave, so the specific accuracy of the position of the transmitter 1 becomes unstable.

[0018] Therefore, in the case of the transmitter 1 of this embodiment, although it will be described in detail later, more than the lower half of the gravity direction (vertical direction) of the transmitter 1 is covered with a fluid having the characteristic of attenuating signals, and the upper part on the side opposite to the gravity direction is not covered with the fluid. Accordingly, the transmission signal sent through the portion covered with the fluid is attenuated by the function of the fluid, and as shown by the dotted line in FIG. 1, its signal level becomes low. So, even if it reaches the receiver 2, the signal level will reach while remaining low.

[0019] In contrast, the transmission signal sent through the portion not covered by the fluid is not attenuated by the function of the fluid, and therefore reaches the receiver 2 with a high signal level, as shown by the solid line in Figure 1. Thus, the signal level of the transmission signal that has passed through the fluid portion of the transmitter 1 is lower than the transmission signal sent from the upper part of the transmitter 1 that reaches the receiver 2 directly, so that the receiver 2 can properly determine the position of the transmitter 1. In other words, the accuracy of determining the position of the transmitter 1 at the receiver 2 can be stabilized. The following describes in detail an example of the configuration of the transmitter 1 and the receiver 2 in this embodiment.

[0020] [Example configuration of Transmitter 1] <Example of structural configuration> Figure 2 is a diagram illustrating an example of the structural configuration of the transmitter 1. The transmitter 1 in this embodiment has a spherical appearance. Figures 2(A), (B), and (C) show cross-sections obtained when the transmitter 1 is cut in half through its centerline, with the front half removed. As shown in Figure 2(A), a space of a predetermined distance is provided between the surface 11 of the spherical transmitter 1 and the inner wall surface 12 located inside the surface 11 (towards the center of the transmitter 1), and this space is the fluid moving layer 13.

[0021] Inside the fluidized bed 13 (towards the center of the transmitter 1), a spherical space called a mechanism mounting section 14 is provided. This mechanism mounting section 14 houses a transmission circuit board section 141 that forms the transmission signal and a transmission antenna section 142 that sends out the transmission signal. In the example shown in Figure 2(A), the transmission circuit board section 141 is mounted on the lower half of the mechanism mounting section 14, and the transmission antenna section 142 is mounted on the upper half.

[0022] A key structural feature of transmitter 1 is the injection of fluid Fd into the fluid moving layer 13. Fluid Fd has the characteristic of attenuating the transmission signal emitted (radiated) by the transmitting antenna section 142. In other words, fluid Fd does not shield the transmission signal, but rather attenuates the transmission signal and radiates it outward. This prevents the transmission signal from being reflected inward and affecting the transmitting circuit board section 141 or the transmitting antenna section 142 within the mechanism mounting section 14.

[0023] Furthermore, the fluid Fd is not injected completely into the fluid moving bed 13. The fluid Fd is injected in such a way that it has an attenuation section 131 that covers more than the lower half in the direction of gravity of the mechanism mounting section 14, and an unattenuated section 132 that does not cover the upper side. In the example shown in Figure 2(A), considering the diameter of the spherical transmitter 1 as the reference, the fluid is injected into the fluid moving bed 13 up to 75% of the way from the lower end to the upper end of the diameter. Therefore, there is no fluid in the 25% of the way from the upper end to the lower end of the diameter.

[0024] In Figure 2(A), the shaded portion of the fluid moving layer 13 is the attenuating portion 131 due to the presence of the fluid Fd, while the unshaded portion of the fluid moving layer 13 is the non-attenuating portion 132 where the fluid Fd is absent. In the example shown in Figure 2(A), the central angle of the arc on the surface of the non-attenuating portion 132 is 120 degrees, and the central angle of the arc on the surface of the attenuating portion 131 is 240 degrees. Therefore, in the cross-sectional view of Figure 2(A), one-third of the upper surface of the transmitter 1 is the non-attenuating portion 132, and two-thirds of the lower surface of the transmitter 1 is the attenuating portion 131. As a result, the signal level of the transmitted signal radiated from the non-attenuating portion 132 is radiated without attenuation, but the signal level of the transmitted signal radiated from the attenuating portion 131 is radiated with attenuation.

[0025] Now, let's consider the case where the transmitting antenna section 142 is located on the upper half of the mechanism mounting section 14 of the transmitter 1, as shown in Figure 2(B). In this case, the transmission signal radiated from the non-attenuating section 132 of the transmitter 1 is more likely to reach the receiver 2, which is installed on the ceiling above the office space, without a reduction in signal level. In contrast, the transmission signal radiated from the attenuating section 131 of the transmitter 1 is attenuated in signal level, so even if it is reflected by iron components such as lockers or desk tops, it will reach the receiver 2 in an attenuated signal level.

[0026] Furthermore, consider the case where the transmitting antenna section 142 is located on the right half of the mechanism mounting section 14 of the transmitter 1, as shown in Figure 2(C). In this case as well, the transmission signal radiated from the non-attenuating section 132 of the transmitter 1 is more likely to reach the receiver 2, which is installed on the ceiling above the office space, without a reduction in signal level. In contrast, the transmission signal radiated from the attenuating section 131 of the transmitter 1 is attenuated in signal level, so even if it is reflected by iron components such as lockers or desk tops, it will reach the receiver 2 in an attenuated signal level.

[0027] As explained using Figure 2(A), by injecting the fluid Fd into the fluid moving layer 13 in such a way that it forms an attenuation section 131 and a non-attenuation section 132, the fluid Fd will always move from a higher position to a lower position due to its own weight. As a result, a non-attenuation section 132 can always be formed on the upper side of the spherical transmitter 1, opposite to the direction of gravity, so that the transmission signal can always be sent upward without attenuating the signal level. However, the transmission signal passing through the attenuation section 131 will have its signal level attenuated, so even if it reaches the receiver 2, it will arrive at a low signal level. As a result, the receiver 2 can properly determine the current position of the transmitter 1 without reducing the accuracy of the positioning.

[0028] <Example of functional configuration> Figure 3 is a block diagram illustrating an example of the functional configuration of transmitter 1. As shown in Figure 3, transmitter 1 comprises an identification information memory 101, a clock circuit 102, a timing control unit 103, a transmission signal formation unit 104, a transmission unit 105, and a transmission antenna 105A. The identification information memory 101 stores and holds a transmitter ID (transmitter identification information) for uniquely identifying transmitter 1. The clock circuit 102 provides the current date and time, as well as timing information for timing predetermined intervals. The timing control unit 103 controls the transmission signal formation unit 104 and the transmission unit 105 to form and transmit a transmission signal at predetermined intervals, such as every 3 seconds or every 5 seconds, based on timing information from the clock circuit 102, for example, every 1 second.

[0029] The transmission signal formation unit 104 forms a transmission signal at predetermined timing intervals based on the control of the timing control unit 103 and supplies it to the transmission unit 105. Figure 4 is a diagram illustrating an example of the format of a transmission signal transmitted from the transmitter 1. This transmission signal is formed by the transmission signal formation unit 104. As shown in Figure 4, the transmission signal consists of the transmitter ID and the transmission date and time. The transmission signal formation unit 104 obtains the transmitter ID of its own unit from the identification information memory 101 and the current date and time from the clock circuit 102, forms the transmission signal shown in Figure 4, and provides it to the transmission unit 105.

[0030] The transmitting unit 105 converts the transmission signal formed by the transmission signal formation unit 104 into a transmission signal, amplifies it, and supplies it to the transmitting antenna 105A. The transmitting antenna 105A realizes the function of transmitting (radiating) the transmission signal from the transmitting unit 105. In this way, the transmitter 1 realizes the function of forming a transmission signal including its own transmitter ID and transmitting it through the transmitting antenna 105A.

[0031] In this embodiment, the part consisting of the identification information memory 101, the clock circuit 102, the timing control unit 103, the transmission signal formation unit 104, and the transmission unit 105 constitutes the transmission circuit board section 141 of the transmitter 1 shown in Figures 2(A), (B), and (C). In this embodiment, the transmission antenna 105A mainly constitutes the transmission antenna section 142 of the transmitter 1 shown in Figures 2(A), (B), and (C). Thus, the components described using Figure 3 are housed in a spherical three-dimensional housing as shown in Figures 2(A), (B), and (C), forming a transmitter 1 having a spherical appearance.

[0032] As described above, in the embodiment, the transmitter 1 is injected with fluid Fd into the fluid moving layer 13 so as to form an attenuation section 131 and an unattenuated section 132. As a result, the attenuation section 131 is formed on the lower side around the mechanism mounting section 14 of the transmitter 1, and the unattenuated section 132 is formed on the upper side around the mechanism mounting section 14 of the transmitter 1 on the opposite side. As a result, the transmission signal passing through the attenuation section 131 is transmitted with its signal level attenuated, and the transmission signal passing through the unattenuated section 132 is transmitted without signal level attenuation. As a result, the transmission signal that has passed through the attenuation section 131 remains at a low signal level when it reaches the receiver 2, while the transmission signal that has passed through the unattenuated section 132 reaches the receiver 2 with a high signal level. This reduces the influence of the transmission signal that has passed through the attenuation section 131 on the receiver 2, and prevents a decrease in the accuracy of the receiver 2 in determining the location (current position) of the transmitter 1.

[0033] <Example of fluid Fd configuration> The fluid Fd can be various liquids such as water, oil, or alcohol, gels with a predetermined viscosity, or various liquids mixed with various materials. Gels with a predetermined viscosity include various gels such as so-called coolants (a mixture of water, superabsorbent polymer, preservatives, and shape stabilizers) or water mixed with gelatin. Various liquids mixed with various materials include, for example, water mixed with finely powdered rubber chips or resin materials such as urethane formed into spheres, or water mixed with various magnetic materials or carbon formed into spheres. In addition, hollow silica dispersions with excellent low-noise suppression properties and carbon nanotube dispersions with radio wave absorption properties can also be used. In short, various fluids that have the property of attenuating radio waves and flowing from high to low places can be used as the fluid Fd injected into the fluid moving layer 13.

[0034] [Example configuration of receiver 2] Next, an example of the configuration of receiver 2 will be described. Figure 5 is a block diagram illustrating an example of the configuration of receiver 2. As shown in Figure 5, receiver 2 comprises a connection terminal 201T, a wired LAN interface 201, a control unit 202, a storage unit 203, receiving antennas 211A(1), 211A(2), 211A(3), 211A(4), a receiving unit 211, and a position detection unit 212.

[0035] The connection terminal 201T constitutes the connection terminal to the LAN (Local Area Network). The wired LANI / F201 enables communication via the LAN. Specifically, the wired LANI / F201 receives signals addressed to itself that are transmitted via the LAN, converts them into a signal format that can be processed by the device, and takes them in. The wired LANI / F201 also converts signals transmitted from itself into a signal format suitable for transmission, sends them to the LAN via the connection terminal 201T, and transmits them to the recipient. This makes it possible to transmit the current position of the transmitter 1, which has been positioned by the receiver 2, to a server device on the LAN, and to determine the positions of multiple different transmitters 1 owned by multiple different users.

[0036] The control unit 202, although not shown in the diagram, is a microprocessor comprising a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and non-volatile memory, and controls various parts of the receiver 2. The storage unit 203 is configured, for example, using non-volatile memory, and stores data used for various programs and processes, as well as the receiver ID (receiver identification information) of the unit itself, and is also used as a work area for temporarily storing information obtained as a result of processing.

[0037] Each of the receiving antennas 211A(1), 211A(2), 211A(3), and 211A(4) receives a transmission signal from the transmitter 1 and supplies it to the receiving unit 211. The receiving unit 211 selects the transmission signal with the highest signal level from the transmission signals received by each of the receiving antennas 211A(1), 211A(2), 211A(3), and 211A(4) from the transmitter 1 and supplies it to the subsequent position detection unit 212. As a result, the transmission signals with the highest signal levels received by each of the receiving antennas 211A(1), 211A(2), 211A(3), and 211A(4) are supplied to the position detection unit 212.

[0038] The position detection unit 212 determines the current position of transmitter 1 and forms position detection information based on the transmission signals from transmitter 1 received by each of the receiving antennas 211A(1), 211A(2), 211A(3), and 211A(4) from the receiving unit 211. Figure 6 is a diagram illustrating an example of position detection information formed by receiver 2. The position detection unit 212 forms position detection information that includes the receiver ID of its own unit stored in the storage unit 203, the transmitter ID included in the transmission signal from transmitter 1 that was received, and the transmitter position information (x, y, z) detected by the position detection unit 212. This formed position detection information is, for example, temporarily stored in the storage unit 203, sent to the LAN via the wired LAN I / F 201 and connection terminal 201T, and provided to a predetermined server device so that the current positions of multiple transmitters 1 owned by multiple users can be determined. In other words, the current positions of each of multiple users can be determined.

[0039] Here, we will explain the processing in the position detection unit 212. As described above, the position detection unit 212 detects the direction in which transmitter 1 is located and the distance to transmitter 1 based on the transmission signals from transmitter 1 received by each of the receiving antennas 211A(1), 211A(2), 211A(3), and 211A(4). There are two types of "direction detection function" technology used in such cases, called the AoA (Angle of Arrival) method and the AoD (Angle of Departure) method, respectively.

[0040] The AoA method involves a single-antenna transmitter sending signals to a multi-antenna receiver. Because of the distance between the antennas, the receiver can receive signals with different phases, and calculates the angle from the phase difference. The AoD method is the reverse of AoA, where the transmitter uses multiple antennas, receiving signals from each antenna and calculating the target angle from the phase difference. In this embodiment, receiver 2 uses AoA technology to determine the position of transmitter 1. Figure 7 illustrates the process of determining the position of transmitter 1 performed by receiver 2.

[0041] First, as shown in Figure 7(A), the position detection unit 212 identifies the distance r from the origin O to the location P of the transmitter 1, with the installation location of the receiver 2 being the origin O. This identification process is performed based on the transmission signals from the transmitter 1 received by the receiving antennas 211A(1), 211A(2), 211A(3), and 111A(4) from the receiving unit 211. Furthermore, the position detection unit 212 determines the angle θ between the z-axis and the straight line OP connecting the origin O and the location P of the transmitter 1. In addition, the position detection unit 212 identifies point Q on the xy-plane, which is the position of the perpendicular line drawn from the location P of the transmitter 1 to the xy-plane, and determines the angle α between the x-axis and the straight line OQ connecting the origin O and point Q on the xy-plane. As a result, as shown in Figure 7(A), the location P of the transmitter 1 in three-dimensional space is specified in polar coordinate form, as shown by (r,θ,α).

[0042] However, if the detected location of transmitter 1 remains in polar coordinate format, subsequent processing becomes difficult. Therefore, as shown in Figure 7(B), the position detection unit 212 calculates the x-coordinate by substituting the obtained (r,θ,α) into equation (1), and the y-coordinate by substituting it into equation (2). Furthermore, it calculates the z-coordinate by substituting it into equation (3). This allows the polar coordinates (r,θ,α) to be converted into three-dimensional coordinates (x,y,z). Using the transmitter position information of transmitter 1 obtained in this way, the position detection unit 212 forms the position detection information explained using Figure 6.

[0043] Thus, in receiver 2, from among the signals received by each of the receiving antennas 211A(1), 211A(2), 211A(3), and 111A(4), only the transmission signal from transmitter 1 with the highest selected signal level by the function of the receiving unit 211 is processed. As a result, reflected waves of transmission signals with low signal levels are excluded from processing, preventing reflected waves from affecting the determination of the transmitter's location and enabling stable positioning of the transmitter 1.

[0044] [Effects of the embodiment] In the case of the transmitter 1 of this embodiment, an attenuation section 131 can be provided to cover the lower side of the mechanism mounting section 14 on which the transmitting circuit board section 141 and the transmitting antenna section 142 are mounted, and a non-attenuation section 132 can be provided to cover the upper side. This makes it easier for the transmitted signal that has passed through the non-attenuation section 132 to reach the receiver 2, which is installed in an upper space such as a ceiling. In this case, even if the transmitted signal that has passed through the attenuation section 131 is reflected by metal or the like and reaches the receiver 2, it has passed through the attenuation section 131, and its signal level is reduced, so the impact on the positioning processing of the transmitter 1's current position can be reduced. In other words, the attenuation section 131 and the non-attenuation section 32 can give directionality to the transmitted signal transmitted from the transmitter 1.

[0045] In other words, regardless of the orientation of transmitter 1, the radio wave attenuating material moves downward due to its own weight, attenuating the radio waves radiated downwards, making it easier to distinguish between reflected waves and direct waves reaching receiver 2. While some radio wave attenuation occurs even with normal reflection, intentionally inserting a radio wave attenuating material increases the amount of attenuation of reflected waves, making it more difficult for them to reach receiver 2, and even if they do, it becomes easier to distinguish them from direct waves based on their signal strength. As a result, even if the configuration of receiver 2 remains the same as before, the positioning accuracy of transmitter 1's current location is not reduced.

[0046] Furthermore, in the transmission and reception system of this embodiment, the receiver 2 can process transmission signals with high signal levels from the transmitter 1. As a result, the transmitter 1 and receiver 2 work together, and in addition to the functions of the transmitter 1 described above, the receiver 2's transmission signal selection function works, enabling accurate positioning of the transmitter 1 without reducing the accuracy of determining the transmitter 1's current position.

[0047] [Differentiation] <Variations in exterior shape> The transmitter 1 in the above-described embodiment was explained as being spherical. However, it is not limited to this. Figures 8 and 9 illustrate other examples of the transmitter 1. Figure 8 shows a transmitter 1A having a rectangular parallelepiped shape, and shows a cross-section when the transmitter 1A is cut in half along a plane containing the center line along the longitudinal direction, and the front side is removed. As shown in Figure 8, the transmitter 1A has a space of a predetermined distance between the surface (side surface) 11A of the rectangular parallelepiped transmitter 1A and the inner wall surface 12A located inside the surface 11A, and this space is the fluid moving layer 13A.

[0048] Inside the fluid moving layer 13A, a rectangular parallelepiped space, the mechanism mounting section 14A, is provided. This mechanism mounting section 14A houses a transmitting circuit board section 141A that forms the transmission signal and a transmitting antenna section 142A that sends out the transmission signal. In the example shown in Figure 8, the transmitting circuit board section 141A is mounted on the lower half of the mechanism mounting section 14A, and the transmitting antenna section 142A is mounted on the upper half.

[0049] An important structural feature of transmitter 1A is that, as with transmitter 1 (Figure 2) described above, fluid Fd is injected into the fluid moving layer 13A. As mentioned above, fluid Fd has the characteristic of attenuating the transmission signal emitted (radiated) by the transmitting antenna section 142A. In other words, fluid Fd does not shield the transmission signal, but rather attenuates the transmission signal and radiates it outwards. This prevents the transmission signal from being reflected inwards and affecting the transmitting circuit board section 141 and the transmitting antenna section 142 within the mechanism mounting section 14.

[0050] Even in the case of transmitter 1A shown in Figure 8, the fluid Fd is not injected completely into the fluid moving layer 13A. The fluid Fd is injected in such a way that there is an attenuation section 131A that covers more than the lower half in the direction of gravity of the mechanism mounting section 14A, and an unattenuated section 132A that does not cover the upper side. In the example shown in Figure 8(A), the longitudinal direction of the rectangular parallelepiped is shown to intersect with the vertical direction, and the fluid Fd is injected into the fluid moving layer 13A up to the upper surface of the transmitting antenna section 142A. Therefore, there is no fluid Fd in the part above the upper surface of the transmitting antenna section 142A.

[0051] In Figure 8(A), the shaded portion of the fluid moving layer 13A is the attenuating portion 131A due to the presence of the fluid Fd. Conversely, the unshaded portion of the fluid moving layer 13A is the non-attenuating portion 132A where the fluid Fd is absent. In the case of the transmitter 1A shown in Figure 8(A), the transmitting antenna portion 142A is located in the upper half of the mechanism mounting portion 14A. Looking at the cross-sectional view in Figure 8(A), the signal level of the transmitted signal radiated from the non-attenuating portion 132A on the upper side of the transmitter 1A is radiated without attenuation, but the signal level of the transmitted signal radiated from the attenuating portion 131A is radiated with attenuation.

[0052] Furthermore, as shown in Figure 8(B), consider the case where the longitudinal direction is aligned with the vertical direction (the transverse direction intersects the vertical direction), and the transmitting antenna section 142 is located on the right half of the mechanism mounting section 14 of the transmitter 1. In this case as well, the transmitted signal radiated from the non-attenuating section 132A of the transmitter 1A is more likely to reach the receiver 2, which is installed on the ceiling above the office space, without a reduction in signal level. In contrast, the transmitted signal radiated from the attenuating section 131A of the transmitter 1A has its signal level attenuated, so even if it is reflected by iron components such as lockers or desk tops, it will reach the receiver 2 in an attenuated state.

[0053] However, as shown in Figure 8(B), the non-attenuated portion 132A becomes larger compared to the state shown in Figure 8(A). In this case, since more transmission signals are sent through the non-attenuated portion 132A, there is a risk that the number of reflected transmission signals that reach the receiver 2 without attenuation will increase. For this reason, there is a risk that the measurement accuracy of the position of the transmitter 1A at the receiver 2 will decrease compared to the case of the spherical transmitter 1 shown in Figure 2.

[0054] Therefore, as shown in Figure 9, it is conceivable to configure a transmitter 1B having a cubic shape. As shown in Figure 9, the transmitter 1B has a predetermined distance of space between the surface (side) 11B of the cubic transmitter 1B and the inner wall surface 12B located inside the surface 11B, and this space is the fluid moving layer 13B. Inside the fluid moving layer 13B, there is a mechanism mounting section 14B which is a cubic space. The mechanism mounting section 14B is equipped with a transmitting circuit board section 141B that forms the transmission signal and a transmitting antenna section 142B that sends out the transmission signal. In the example shown in Figure 9, the transmitting circuit board section 141B is mounted on the lower half of the mechanism mounting section 14B and the transmitting antenna section 142B is mounted on the upper half.

[0055] In transmitter 1B, as with transmitters 1 (Figure 2) and 1A (Figure 8) described above, the important structural feature is that the fluid Fd is injected into the fluid moving layer 13B. As mentioned above, the fluid Fd has the characteristic of attenuating the transmission signal emitted (radiated) by the transmitting antenna section 142B. In the case of transmitter 1B shown in Figure 9, the fluid Fd is not injected completely into the fluid moving layer 13B. The fluid Fd is injected in such a way that it forms an attenuation section 131B that covers more than the lower half in the direction of gravity of the mechanism mounting section 14B, and an unattenuated section 132B that does not cover the upper side. In the example shown in Figure 9(A), the fluid is injected into the fluid moving layer 13B up to the upper surface position of the transmitting antenna section 142B. Therefore, there is no fluid in the part above the upper surface position of the transmitting antenna section 142B.

[0056] In Figure 9(A), the shaded portion of the fluid moving layer 13A is the attenuating portion 131B due to the presence of the fluid Fd. Conversely, the unshaded portion of the fluid moving layer 13B is the non-attenuating portion 132B where the fluid Fd is absent. In the case of the transmitter 1B shown in Figure 9(A), the transmitting antenna portion 142B is located in the upper half of the mechanism mounting portion 14B. Looking at the cross-sectional view in Figure 9(A), the signal level of the transmitted signal radiated from the non-attenuating portion 132A on the upper side of the transmitter 1B is radiated without attenuation, but the signal level of the transmitted signal radiated from the attenuating portion 131B is radiated with attenuation.

[0057] Furthermore, consider the case where the transmitting antenna section 142 is located on the right half of the mechanism mounting section 14 of the transmitter 1, as shown in Figure 9(B). In this case, as can be seen by comparing Figure 9(A) and Figure 9(B), the relationship between the attenuating section 131B and the non-attenuating section 132B with respect to the mechanism mounting section 14B remains unchanged. Therefore, even if the transmitter 1B is tilted, the relationship between the attenuating section 131B and the non-attenuating section 132B with respect to the mechanism mounting section 14B does not change, and it becomes possible to function in almost the same way as the spherical transmitter 1 explained using Figure 2.

[0058] As can be seen from the descriptions of the spherical transmitter 1 in Figure 2, the rectangular transmitter 1A in Figure 8, and the cubic transmitter 1B in Figure 9, it is preferable that the relationship between the mechanism mounting part and the attenuating and non-attenuating parts does not change when the transmitter is rotated (tilted). Therefore, as long as this condition is satisfied, the external shape of the transmitter can be various.

[0059] <Thickness of the fluid moving bed> Furthermore, the thickness of the fluid moving layers 13, 13A, and 13B of transmitters 1, 1A, and 1B can be set to an appropriate distance so that the injected fluid flows smoothly without stagnation when transmitters 1, 1A, and 1B are tilted. This is true when transmitters are configured in various shapes. Therefore, the size of the transmitter housing itself can also be made in various sizes.

[0060] <Expansion of applicable environments> In the embodiments described above, the transmitter and transmission / reception system according to this invention were used to construct a transmission / reception system (indoor positioning system) in a company office. However, it is not limited to this. It can be used in various locations such as factories, construction sites, and large event venues. Furthermore, the transmitter and transmission / reception system according to this invention is not limited to indoor positioning systems. Even outdoors, for example, by installing multiple receivers 2 at high places such as pillars or walls and setting a position detection area, a positioning system in a predetermined area indoors can be constructed.

[0061] For example, a positioning system can be constructed in the spectator seating areas of outdoor stadiums, soccer fields, and racecourses using the transmitter and transmission / reception system according to this invention. This allows for the construction of positioning systems for various purposes, such as attaching transmitter 1 to a child to enable early detection if they get lost, guiding them back to their seat, or determining the location of acquaintances.

[0062] <Materials for the transmitter's 3D casing> The material used for the three-dimensional casings of transmitters 1, 1A, and 1B should be transparent to radio waves, water-resistant, strong enough to withstand some external pressure, resistant to the fluids used, and easy to mold. For example, resin materials such as polycarbonate, ABS resin, and acrylic resin can be used.

[0063] <Gimbalization of the mechanism consisting of the transmitting circuit board and transmitting antenna section> As explained using Figure 2, the transmitting circuit board 141 and the transmitting antenna 142 are fixed to the mechanism mounting section 14 within the three-dimensional housing. As a result, even if the transmitting antenna 142 is facing upward in the opposite direction to gravity, as shown in Figure 2(B), if the transmitter 1 rotates 90 degrees clockwise, as shown in Figure 2(C), the transmitting antenna 142 will be positioned to the right of the mechanism mounting section 14. Therefore, theoretically, there is a case where the transmitting antenna 142 is positioned downward in the direction of gravity, and the transmitting circuit board 141 is positioned above it, the opposite of the state shown in Figure 2(B). However, even in this case, the signal transmitted from the transmitting antenna 142 is radiated in all directions, so it can be transmitted through the transmitting circuit board 141 and the non-attenuating section 132.

[0064] However, it would be even better if the transmission signal from the transmitting antenna unit 142 could always be sent directly from the non-attenuating section 132 formed above the mechanism mounting unit 14. For this reason, by mounting the transmitting circuit board unit 141 and the transmitting antenna unit 142, which are mounted on the mechanism mounting unit 14, on a so-called gimbal, the transmitting antenna unit 142 can always be positioned to face the upper side where the non-attenuating section 132 is formed. A gimbal is a type of rotating platform that rotates an object around a single axis, and by setting up gimbals so that the axes are perpendicular, the orientation of the rotor mounted on the inner gimbal can always be kept constant. Gimbals are used, for example, in gyroscopes, compasses, stoves, and drink holders mounted on ships and aircraft, and are always positioned perpendicular to the horizon. As gimbals are already widely used, a description of their configuration examples will be omitted. [Explanation of symbols]

[0065] 1, 1A, 1B...Transmitter, 101...Identification information memory, 102...Clock circuit, 103...Timing control unit, 104...Transmit signal formation unit, 105...Transmitting unit, 105A...Transmitting antenna, 11, 11A, 11B...Surface, 12, 12A, 12B...Inner wall surface, 13, 13A, 13B...Fluid moving layer, 131, 131A, 131B...Attenuation unit, 132, 132A, 132B...Non-attenuation unit, 14, 14A, 14B... Mechanism mounting section, 141, 141A, 141B... Transmitting circuit board section, 142, 142A, 142B... Transmitting antenna section, Fd... Fluid, 2... Receiver, 201T... Connection terminal, 201... Wired LAN I / F, 202... Control section, 203... Memory section, 211A(1), 211A(2), 211A(3), 211A(4)... Receiving antenna, 211... Receiving section, 212... Position detection section

Claims

1. A transmitter comprising a transmitting circuit board section that forms a transmission signal and a transmitting antenna section that sends out the transmission signal, mounted in a three-dimensional housing, The aforementioned three-dimensional enclosure is A fluid transfer layer is formed by separating an externally exposed surface from an internal wall surface facing the inside of the externally exposed surface by a predetermined distance. A mechanism mounting section is provided inside the fluid moving layer, on which the transmitting circuit board and the transmitting antenna are mounted. Equipped with, The fluid transfer layer is in which a fluid having a signal attenuation function is injected, such that it has an attenuation section that covers more than the lower half in the direction of gravity of the mechanism mounting section and a non-attenuation section that does not cover the upper side. A transmitter characterized by the following features.

2. A transmitting and receiving system comprising a transmitter and one or more receivers installed above the height at which the transmitter is located, The aforementioned transmitter is The system consists of a transmitting circuit board that forms a transmission signal and a transmitting antenna that sends out the transmission signal, both mounted in a three-dimensional housing. The aforementioned three-dimensional enclosure is A fluid transfer layer is formed by separating an externally exposed surface from an internal wall surface facing the inside of the externally exposed surface by a predetermined distance. A mechanism mounting section is provided inside the fluid moving layer, on which the transmitting circuit board and the transmitting antenna are mounted. Equipped with, The aforementioned fluid moving layer is injected with a fluid having a signal attenuation function, such that it has an attenuation section that covers more than the lower half in the direction of gravity of the mechanism mounting section, and a non-attenuation section that does not cover the upper part. The aforementioned receiver is Multiple receiving antennas that receive the transmission signal from the transmitter, A receiving unit that selects the transmission signal with the highest received signal level for each of the multiple receiving antennas to be processed. A transmission and reception system characterized by comprising the following features.

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