JP6589022B1 - Position detection system - Google Patents

Abstract

A position detection system for measuring a distance using an inexpensive device that transmits and receives a sound wave and a magnetic field is provided. A magnetic field generator 103 that generates a magnetic field 105 installed on a wall surface 101, a sound wave transmitter 107 that transmits a sound wave signal 109 simultaneously with the generation of the magnetic field 105, and a moving object 111 are installed on the wall surface 101. And a sound wave receiver 113 that receives the magnetic field 105 and the sound wave signal 109. The sound wave receiver 113 receives the magnetic field 105, and determines the time from when the magnetic field 105 is received until the sound wave signal 109 is received. By measuring, a position detection system is provided in which the position of the sound wave transmitter 107 from the wall surface 101 is measured. [Selection] Figure 1

Description

  The present invention relates to a position detection system that detects the position of an object in a certain area.

  In order to measure the position of the object from the wall surface with an inexpensive device, a sound wave transmitter / receiver is installed on the wall surface, the sound wave is transmitted to the object by the transmitter, and the sound wave bounced off the object by the receiver is received. Receive and measure the time from transmission to reception. By applying time and speed of sound, the reciprocating distance between the wall surface and the object can be understood.

  However, a reflective material such as a person that absorbs sound is weak against acoustic noise because sound waves are attenuated by reflection, and is not suitable for measurement using sound waves. Therefore, as disclosed in Patent Document 1, it is disclosed that a transmitter and a receiver are respectively attached to the left and right ankles of a person and the stride is measured.

JP 2000-46578 A

  However, the stride measuring device of Patent Document 1 measures the time based on the phase difference of sound waves by combining the time of the transmitter and the receiver. Therefore, the transmitter always outputs the time to the connection connector, and it is necessary to obtain the time by connecting to the receiver.

  Moreover, since the sound wave used for the measurement uses a frequency of about 100 Hz, a phase difference could not be detected at a distance of 4 m or more. Furthermore, it was not supposed to measure the position of multiple receivers.

  Therefore, the present invention provides a position detection system that measures distance using an inexpensive device that transmits and receives sound waves and magnetic fields. Also provided is a position detection system that measures the distance to a moving object within a certain range (for example, several meters to several tens of meters from a wall). Moreover, the position detection system which measures the position of a some receiver by transmission of the sound wave signal once is provided.

  In order to solve the above problems, the position detection system according to the present invention is configured as follows.

First, a position detection system according to one embodiment of the present invention includes:
A magnetic field generator for generating a magnetic field installed on the wall;
A sound wave transmitter installed on the wall surface for transmitting a sound wave signal simultaneously with the generation of the magnetic field;
A sound wave receiver attached to a moving object and receiving the magnetic field and the sound wave signal,
The sound wave receiver receives the magnetic field, and measures the time from receiving the magnetic field to receiving the sound wave signal, thereby measuring the position of the sound wave transmitter from the wall surface. It is a feature.

  With the above configuration, since the timing at which the sound wave signal is output from the sound wave transmitter is transmitted wirelessly by the magnetic field, it is not necessary to provide a timer in the sound wave transmitter and the sound wave receiver.

  Since the present invention uses the speed of sound waves (approximately 340 m / s), it is possible to measure the distance in the range of several meters to several tens of meters. The cost of a transceiver using a sound wave signal can be kept low.

  Using a sound wave signal and a magnetic field can wrap around and penetrate even if there is a shield, so that the measurable area can be expanded more than light. Also, unlike radio waves, magnetic fields are less legally restricted in use. Furthermore, although the sound wave transmitter requires electric power, the sound wave receiver attached to the moving object only receives a signal, so it is lightweight and can reduce power consumption.

The present invention also provides:
The wall surface encloses a predetermined range,
A plurality of the sound wave transmitters are installed on the wall surface,
The position of the acoustic wave receiver from the wall surface is measured in two dimensions or three dimensions.

  By installing a plurality of sound wave transmitters on the wall surface, the position of the sound wave receiver can be measured in two dimensions of front and rear, left and right, or three dimensions of front and rear, right and left.

  Further, the present invention is characterized in that the plurality of sound wave transmitters have different frequencies of the sound wave signals to be transmitted.

  With the above configuration, the sound wave signals from the respective sound wave transmitters can be identified. Even if a sound wave signal is output simultaneously with the generation of the magnetic field from each sound wave transmitter, the sound wave receiver can identify the sound wave signal from which sound wave transmitter and measure each distance.

  In the present invention, the plurality of sound wave transmitters installed on the opposing wall surfaces simultaneously transmit sound waves, and the relative position of the sound wave receivers from the wall surfaces is measured, whereby the sound wave receivers The position from the wall surface is calculated.

  With the above configuration, if the distance between the transmitters facing each other is known as, for example, 3 m in height, the position of the sound wave receiver is measured as 2 m from the top and 1 m from the bottom, It is confirmed that the measurement was successful. If it seems to deviate significantly, it can be eliminated as an error value. Further, since the relative position is measured, the temperature correction of the sonic speed is not necessary.

The present invention also provides:
There are multiple sound wave receivers,
The plurality of sound wave receivers receive one sound wave signal from the sound wave transmitter, whereby the positions of the plurality of sound wave receivers are measured at a time.

  With the above configuration, the sound wave has low directivity, and simultaneous measurement of a plurality of moving objects can be performed. The measurement frequency varies depending on the distance between the sound wave transmitter and the sound wave receiver. If the distance is 34 m, it takes about 100 ms for the transmitted sound wave signal to be received, so measurement at 10 times / second can be performed. However, there is an advantage that the measurement frequency does not decrease even if the number of sound wave receivers increases.

  Further, the present invention is characterized in that the sound wave receiver is attached to a plurality of locations of the moving object.

  With the above configuration, motion capture can be performed. Further, for example, it is possible to measure the linkage between the direction in which the face is facing and the movement of the hand or foot.

  Further, the present invention is characterized in that the wall surface is provided in four directions or six directions of a basketball court, and the moving object is a basketball player.

  With the above configuration, the movement of the player during the basketball game can be measured. The game can be analyzed by measuring the movement of the player. In addition, the motion of basketball players can be measured by motion capture. By observing the movement of the player and the direction of the face, you can analyze the exact movement of the player.

  By analyzing the game and the player's movements, you can develop strategies and strengthen your team.

  According to the present invention, the wall surface is provided in four or six directions of a work place, and the moving object is an operator.

  With the above configuration, it is possible to grasp the movement of the worker in the workplace. By grasping the movement of the worker, it is possible to devise an efficient work procedure and to grasp and instruct emergency evacuation.

It is a figure explaining the position detection system which concerns on Embodiment 1 of this invention. It is a figure explaining the position detection system which concerns on Embodiment 2 of this invention. It is a figure explaining the position detection system which concerns on Embodiment 3 of this invention. It is a figure explaining the position detection system which concerns on Embodiment 4 of this invention. It is a figure explaining that the sound wave receiver of this invention is attached to the multiple places of the moving object. It is a figure in which the position detection system of the present invention is applied to a basketball court and a player. It is the figure where the position detection system of this invention was applied to the workplace and the worker.

  Hereinafter, an embodiment for carrying out the present invention will be described. In the drawings, corresponding members having the same functions are denoted by the same reference numerals. In the drawings, the description of corresponding members having the same function may be omitted. In consideration of ease of explanation or understanding of the main points, the embodiments are shown separately for convenience, but partial replacement or combination of configurations shown in different embodiments is possible. In the second and subsequent embodiments, description of matters common to the first embodiment will be omitted, and only different points will be described. In particular, the same operation and effect of the same configuration will not be sequentially described for each embodiment.

(Embodiment 1)
FIG. 1 is a diagram illustrating a position detection system according to Embodiment 1 of the present invention. A position detection system according to Embodiment 1 of the present invention will be described with reference to FIG.

  As shown in FIG. 1, in the position detection system of the present embodiment, the magnetic field generator 103 is embedded in the floor, and the sound wave transmitter 107 is embedded in the wall surface 101. A person who is a moving object 111 is located at a distance within a predetermined range (several meters to several tens of meters) from the wall surface 101, and a sound wave receiver 113 is attached thereto.

  The distance between the moving object 111 and the wall surface is measured as follows. A magnetic field 105 is generated from the magnetic field generator 103, and a sound wave signal 109 is simultaneously generated from the sound wave transmitter 107.

  A magnetic field having a band of 110 kHz to 205 kHz can be used. This band is of the non-contact power supply standard (Qi standard), and the Qi standard is commercially available and can be obtained at low cost. Further, it is possible to send information to the sound wave receiver using the Qi standard protocol or to wirelessly power the sound wave receiver 113.

  The sound wave signal is a sound wave having a certain frequency, and it is preferable that the sound wave signal is an ultrasonic wave because it is difficult to be mixed with surrounding sounds.

The speed of sound is about 340 m per second at room temperature, and the speed of light is 3 × 10 ⁸ m in the atmosphere. Since the magnetic field is transmitted at the same speed as the speed of light, it reaches the sound wave receiver 113 by orders of magnitude faster than the sound wave. The time to reach the sound wave receiver 113 after the generation of the magnetic field is considered to be almost simultaneous.

Therefore, the time for receiving the sound wave signal after the sound wave receiver 113 receives the change of the magnetic field is the time for the sound wave signal to reach the sound wave receiver 113 from the wall surface 101. Assuming that the speed of sound is v (m / second) and the time for the sound wave signal to reach the sound wave receiver 113 from the wall surface 101 is t (second), the distance d (m) between the wall surface 101 and the moving object 111 is
d = vt
It is represented by

  The distance d measured by the sound wave receiver 113 is transmitted to the measurement data processing device 117 by the radio wave 115. The time t may be transmitted as data, and the distance d may be calculated by the measurement data processing device 117.

  Here, an example in which the magnetic field generator and the sound wave transmitter are embedded in the wall surface is shown. However, the magnetic field generator and the sound wave transmitter may exit from the wall surface and are preferably in the vicinity of the wall surface. Similarly, in the following embodiments, the installation location of the sonic wave transmitter may be embedded in the wall surface or may exit from the wall surface, and is preferably in the vicinity of the wall surface.

  Moreover, although the example in which the magnetic field generator was embedded in the floor was shown, it may have come out of the floor and may be further installed so that a wall surface may be enclosed. The magnetic field generator may be installed on the ceiling. Similarly, in the following embodiments, the magnetic field generator may be embedded in the floor or may be out of the floor, and may be installed so as to surround the wall surface or may be installed on the ceiling. .

(Embodiment 2)
FIG. 2 is a diagram illustrating a position detection system according to the second embodiment of the present invention. A position detection system according to Embodiment 2 of the present invention will be described with reference to FIG.

  As shown in FIG. 2, in the position detection system of the present embodiment, the magnetic field generator 203 is embedded in the floor, and the sound wave transmitter 207 is embedded in the wall surface 201. A sound wave transmitter 208 is embedded in the wall surface 202 adjacent to the wall surface 201. A person who is a moving object 211 is located in a predetermined range (several meters to several tens of meters) from the wall surface 201 and the wall surface 202, and a sound wave receiver 213 is attached thereto.

  In the present embodiment, since the plurality of sound wave transmitters 207 and 208 are installed on the wall surface 201 and the wall surface 202, the position of the moving object 211 can be measured two-dimensionally.

  A magnetic field 205 is generated from the magnetic field generator 203, and simultaneously, a sound wave signal 209 is generated from the sound wave transmitter 207, and a sound wave signal 210 is generated from the sound wave transmitter 208. The sound wave signals 209 and 210 are preferably simultaneous, but may be transmitted with a time difference. The sound wave signals 209 and 210 are sound waves having different frequencies.

Similar to the first embodiment, the distance d ₁ from the sound wave transmitter 207 can be determined by measuring the time from when the sound wave receiver 213 receives the magnetic field 205 to when the sound wave signal 209 is received. Further, the distance d ₂ from the sound wave transmitter 207 can be obtained by measuring the time from when the sound wave receiver 213 receives the magnetic field 205 to when the sound wave signal 209 is received.

When the wall surfaces 201 and 202 form a right angle, the contact point between the wall surfaces 201 and 202 is the origin (0, 0), the wall surface 202 is the X axis, and the wall surface 201 is the Y axis, the position (x, y) of the sound wave receiver is The distance (d ₂ , d ₁ ) can be an approximate value.

Strictly speaking, the position of the sound wave transmitter 207 on the wall surface 201 is (0, y ₁ ), the position of the sound wave transmitter 208 on the wall surface 202 is (x ₁ , 0), and the distance from the sound wave transmitter 207 to the sound wave receiver 213. Is d ₁ , the distance from the sound wave transmitter 208 to the sound wave receiver 213 is d ₂ , and the position (x, y) of the sound wave receiver is
(Xx ₁ ) ² + y ² = d ₁ ²
x ² + (y−y ₁ ) ² = d ₂ ²
The position from the origin can be calculated by solving the simultaneous equations.

  As described above, the sound wave receiver 213 can measure the position of the moving object 211 in a two-dimensional manner since it can be seen that the sound wave receiver 213 is at the position x from the wall surface 201 and the position y from the wall surface 202. By installing the acoustic wave transmitter on the adjacent wall surface, the position of the acoustic wave receiver can be measured in two dimensions of front and rear, left and right, or three dimensions of front and rear, right and left, and up and down.

The position (x, y) measured by the sound wave receiver 213 is transmitted to the measurement data processing device 217 by the radio wave 215. Time t ₁ , t ₂ or distances d ₁ , d ₂ may be transmitted as data, and the position (x, y) may be calculated by the measurement data processing device 217.

  In the present embodiment, an example in which one acoustic wave transmitter is installed on one wall surface is shown, but a plurality of acoustic wave transmitters may be installed on one wall surface. The sound wave receiver can increase the accuracy of the position by measuring the distance from each. If signals from three sound wave transmitters are received, there are sound wave receivers at the intersections of circles having a radius from each of the sound wave transmitters.

  When a plurality of sound wave transmitters are installed on one wall surface, ultrasonic waves having different frequencies may be mixed. In this case, for example, the sound wave transmitter in the X direction transmits sound waves of 38 kHz, 40 kHz, and 42 kHz, and the sound wave transmitter in the Y direction transmits sound waves of 44 kHz, 46 kHz, and 48 kHz. When sound waves are mixed in this way, the measurement becomes stronger against room temperature noise.

(Embodiment 3)
FIG. 3 is a diagram illustrating a position detection system according to Embodiment 3 of the present invention. A position detection system according to Embodiment 3 of the present invention will be described with reference to FIG.

  As shown in FIG. 3, in the position detection system of the present embodiment, the magnetic field generator 303 is embedded in the floor, and the sound wave transmitter 307 is embedded in the wall surface 301. A sonic transmitter 308 is embedded in a wall 302 facing the wall 301. A person who is a moving object 311 is located within a distance (several meters to several tens of meters) from the wall surface 301 and the wall surface 302, and a sound wave receiver 313 is attached thereto.

  In the present embodiment, since the sound wave transmitters 307 and 308 are respectively embedded in the opposing wall surface 301 and wall surface 302, the moving object 311 can be relatively measured.

  A magnetic field 305 is generated from the magnetic field generator 303, and simultaneously, a sound wave signal 309 is generated from the sound wave transmitter 307 and a sound wave signal 310 is generated from the sound wave transmitter 308. The sound wave signals 309 and 310 are sound waves having different frequencies.

Similar to the first embodiment, the sound wave receiver 313 measures a time t ₃ from when the magnetic field 305 is received until the sound wave signal 309 is received. In addition, the time t ₄ from when the sound wave receiver 313 receives the magnetic field 305 to when the sound wave signal 309 is received is measured.

If the distance _dt between the wall surface 301 and the wall surface 302 is known, the distance d ₃ from the wall surface 301 is
d ₃ = t ₃ · d _t / (t ₃ + t ₄ )
Is required. The distance d ₄ from the wall surface 302 is
d ₄ = t ₄ · d _t / (t ₃ + t ₄ )
Is required.

  Thus, if the distance between the opposing wall surface 301 and the wall surface 302 is known, the absolute position from the wall surface 301 and the wall surface 302 is calculated by measuring the relative time (relative position) between the wall surface 301 and the wall surface 302. The

By doing so, the position can be detected without correcting the temperature of sound speed. Further, since the distances d ₃ and d ₄ can be roughly estimated from the times t ₃ and t ₄ , values far from d _t can be repelled as error values.

  Moreover, it turns out that it exists in the position where the line parallel to the opposing wall surface was drawn. For example, in the case of a single sound wave transmitter, if the sound wave receiver is positioned obliquely from the sound wave transmitter, it is calculated to be longer than the distance from the actual wall surface (about 1.41 times at 45 °), In the case of this embodiment, such a thing can be prevented.

The distances d ₃ and d ₄ measured by the sound wave receiver 313 are transmitted to the measurement data processing device 317 by the radio wave 315. Times t ₃ and t ₄ may be transmitted as data, and the distances d ₃ and d ₄ may be calculated by the measurement data processing device 317.

  The sound wave signals 309 and 310 may be transmitted with a time difference. If the time difference is a predetermined time difference, the relative time (relative position) can be measured by subtracting that amount.

  In combination with the second embodiment, the present embodiment can measure the position of a moving object surrounded by four front and rear, right and left walls in two dimensions and the absolute position from each wall surface. In addition, the position of a moving object surrounded by six directional walls in the front, rear, left, right, and upper directions can be measured in three dimensions and the absolute position from each wall surface can be measured.

(Embodiment 4)
FIG. 4 is a diagram illustrating a position detection system according to Embodiment 4 of the present invention. A position detection system according to Embodiment 4 of the present invention will be described with reference to FIG.

  As shown in FIG. 4, in the position detection system of this embodiment, a magnetic field generator 403 is embedded in the floor, and a sound wave transmitter 407 is embedded in the wall surface 401. A person who is a plurality of moving objects 411 and 412 is located at a distance within a predetermined range (several meters to several tens of meters) from the wall surface 401, and sound wave receivers 413 and 414 are respectively attached thereto.

  In the present embodiment, there are a plurality of sound wave receivers at a distance in a predetermined range, and a plurality of sound wave receivers receive one sound wave signal from the sound wave transmitter, thereby positioning the plurality of sound wave receivers, It can be measured at once.

A magnetic field 405 is generated from the magnetic field generator 403, and at the same time, a sound wave signal 409 is transmitted from the sound wave transmitter 407. The sound wave receivers 413 and 414 receive the magnetic field 405 simultaneously. The sound wave receivers 413 and 414 receive the sound wave signal 409 after the elapse of times t ₅ and t ₆ corresponding to the distances d ₅ and d ₆ from the wall surface 401.

The distances d ₅ and d ₆ measured by the sound wave receivers 413 and 414 are transmitted to the measurement data processing device 417 by radio waves 415. Times t ₅ and t ₆ may be transmitted as data, and the distances d ₅ and d ₆ may be calculated by the measurement data processing device 417.

  By combining with the first to third embodiments, the positions of a plurality of moving objects within a predetermined range from the wall surface can be simultaneously measured in two dimensions or three dimensions.

(Embodiment 5)
FIG. 5 is a diagram for explaining that the sound wave receiver of the present invention is attached to a plurality of locations of a moving object. With reference to FIG. 5, motion capture using the fact that the sound wave receiver of the present invention is attached to a plurality of locations of a moving object will be described.

  By combining with the first to fourth embodiments, motion capture is possible by attaching the sound wave receiver of the present invention to a moving object in a room in a certain range (several meters to several tens of meters) at a plurality of locations. For example, a sound wave receiver attached to the head can follow the direction in which the face is facing and can measure the link between the direction in which the face is facing and the movement of the hand.

  Further, by combining with Embodiments 1 to 4, it is possible to measure the movements of a plurality of moving objects (for example, players) within a certain range.

  For example, in a room surrounded by a wall surface with a distance of 10 m, a sound wave signal can be transmitted at about 34 times / second. If it is a room surrounded by a wall surface with a distance of 34 m, it is possible to transmit a sound wave signal at about 10 times / second.

(Embodiment 6)
FIG. 6 is a diagram in which the position detection system of the present invention is applied to a basketball court and a player. A case where the position detection system of the present invention is applied to a basketball court and a player will be described with reference to FIG.

  The sound wave transmitters 603, 605, 607, 609, 611 and the measurement data processing device 613 are embedded in the wall surface. Similarly, a sound wave transmitter is also embedded in the wall surface on the near side of the drawing. The magnetic field generator 601 is embedded in the floor. . Here, an example in which the magnetic field generator and the sound wave receiver are embedded in the floor and the wall surface is shown. However, the magnetic field generator and the sound wave receiver may protrude from the floor and the wall surface, and are preferably near the floor and the wall surface.

  A sound wave receiver 615, 617, 619, 621 is attached to each basketball player. Here, only 4 people are shown in a simplified manner, but there are usually 10 people on the court, and the number of people is not particularly limited.

  By using the position detection system of the present invention described in the first to fourth embodiments, the position of the player can be measured at regular time intervals. By measuring the position of the player, the movement of the player during the basketball game can be observed.

  Although not shown, by applying the position detection system of the present invention to a plurality of locations of the player as in the fifth embodiment, it is possible to observe the movement of the player and the movement of the face.

  The game can be analyzed by observing player movement. In addition, by observing the movement of the player and the direction of the face, it is possible to analyze the exact movement of the player. By analyzing the game and the player's movements, you can develop strategies and strengthen your team.

(Embodiment 7)
FIG. 7 is a diagram in which the position detection system of the present invention is applied to a work place and a worker. A case where the position detection system of the present invention is applied to a work place and a worker will be described with reference to FIG.

  The magnetic field generator 701, the sound wave transmitters 703, 705, 707, 709, 711, 713, 715, 717 and the measurement data processing device 719 are embedded in the floor, wall surface, and ceiling. Here, an example in which the magnetic field generator and the sound wave receiver are embedded in the floor, the wall surface, and the ceiling is shown. However, the magnetic field generator and the sound wave receiver may protrude from the floor, the wall surface, and the ceiling, and are preferably near the floor, the wall surface, and the ceiling.

  The sound wave receivers 721, 723, and 725 are attached to workers. In addition, the sonic transmitter 727 may be attached to a forklift that is a moving object.

  By using the position detection system of the present invention described in Embodiments 1 to 4, it is possible to grasp the movement of the worker in the work place. Further, by applying the position detection system of the present invention to a plurality of positions of the worker as in the fifth embodiment, it is possible to analyze an accurate operation of the worker.

  By grasping the movement and operation of the worker, it is possible to plan an efficient work procedure and to grasp and instruct emergency evacuation. By grasping the behavior of a moving machine such as a forklift, an efficient work procedure can be planned.

  The moving object to which the position detection system of the present invention is applied is not limited to a person, but also includes animals kept in cages, automatic transfer devices in warehouses, and the like.

DESCRIPTION OF SYMBOLS 101 Wall surface 103 Magnetic field generator 105 Magnetic field 107 Sound wave transmitter 109 Sound wave signal 111 Moving object 113 Sound wave receiver 115 Radio wave 117 Measurement data processing apparatus

Claims (8)

A magnetic field generator for generating a magnetic field installed on the floor or ceiling ;
A sound wave transmitter installed on the wall surface for transmitting a sound wave signal simultaneously with the generation of the magnetic field;
A sound wave receiver attached to a moving object and receiving the magnetic field and the sound wave signal,
The sound wave receiver receives the magnetic field, and measures the time from receiving the magnetic field to receiving the sound wave signal, thereby measuring the position of the sound wave transmitter from the wall surface. Detection system. A magnetic field generator for generating a magnetic field installed on the floor or ceiling ;
A sound wave transmitter installed on the wall surface for transmitting a sound wave signal simultaneously with the generation of the magnetic field;
A sound wave receiver attached to a moving object and receiving the magnetic field and the sound wave signal,
The sound wave receiver receives the magnetic field, and measures the time from receiving the magnetic field to receiving the sound wave signal, thereby measuring the position of the sound wave transmitter from the wall surface,
The position detection system , wherein the wall surface is provided in four directions or six directions of a basketball court, and the moving object is a basketball player . A magnetic field generator for generating a magnetic field installed on the floor or ceiling ;
A sound wave transmitter installed on the wall surface for transmitting a sound wave signal simultaneously with the generation of the magnetic field;
A sound wave receiver attached to a moving object and receiving the magnetic field and the sound wave signal,
The sound wave receiver receives the magnetic field, and measures the time from receiving the magnetic field to receiving the sound wave signal, thereby measuring the position of the sound wave transmitter from the wall surface,
The position detection system , wherein the wall surface is provided in four or six directions of a work place, and the moving object is a worker . The wall surface encloses a predetermined range,
A plurality of the sound wave transmitters are installed on the wall surface,
The position detection system according to any one of claims 1 to 3, wherein a position of the acoustic wave receiver from the wall surface is measured in two dimensions or three dimensions. The position detection system according to claim 4 , wherein the plurality of sound wave transmitters have different frequencies of the sound wave signals to be transmitted. The plurality of sound wave transmitters installed on the opposing wall surfaces simultaneously transmit sound waves, and the relative position of the sound wave receiver from the wall surface is measured, whereby the position of the sound wave receiver from the wall surface is determined. The position detection system according to claim 4 or 5 , wherein the position detection system is calculated. There are multiple sound wave receivers,
Wherein the plurality of acoustic receivers, by receiving one of a sound wave signal from the wave transmitter, the position of the plurality of sonic receivers is measured at a time, any one of claims 1 to 6 The position detection system described in. The position detection system according to claim 7 , wherein the acoustic wave receiver is attached to a plurality of locations of the moving object.

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