JP2005196350A - Information input device, its control method, control program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information input device that enables information about a moving body to be inputted by means of a simple arrangement without using optical communications; its control method; a control program; and a recording medium for recording the control program. <P>SOLUTION: A pen type moving body 2 sends an ultrasonic signal S1 in synchronism with the timing of synchronizing communication with an input device 1. The input device 1 calculates the propagation time of the ultrasonic signal S1 on the basis of a time difference between the timing of synchronizing communication with the pen type moving body 2 and the timing of receiving the ultrasonic signal S1. The position of the pen type moving body 2 is calculated on the basis of a propagation distance calculated from the propagation time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an information input device that inputs information using a moving body, a control method thereof, a control program, and a recording medium.

2. Description of the Related Art Conventionally, a coordinate input device that inputs coordinate information to an external device such as a personal computer using a pen-type controller is known. In this type of coordinate input device, the pen-type operator has a function of wirelessly transmitting an ultrasonic signal and an infrared synchronization signal, and calculates the position of the pen-type operator from the reception results of these signals. (For example, patent document 1). More specifically, in this coordinate input device, the pen type moving body is synchronized with an infrared synchronization signal transmitted from the pen type moving body, and the pen type moving body transmits an ultrasonic signal from this synchronization timing. Knowing the timing and acquiring the transmission timing and the time until the reception timing of the ultrasonic signal as the propagation time of the ultrasonic wave, the distance from the propagation time to the pen-type controller can be calculated.
JP 2003-288157 A

  However, the information input device having the above-described wireless connection configuration performs optical communication using infrared rays, and thus is vulnerable to optical disturbance due to illumination light or the like, and cannot be used when there is a light shielding object between the pen-type controller and the like. There is a problem such as. In addition, if there is one LED for optical communication, the orientation and position of the pen-type moving body and the information input device are limited. If many LEDs are provided to eliminate this limitation, the pen-type There arises a problem that the operation element is enlarged.

  The present invention has been made in view of the above-described circumstances, and an information input device capable of inputting information of a moving body with a simple configuration without using optical communication, a control method thereof, a control program, and this control An object of the present invention is to provide a recording medium on which a program is recorded.

  In order to solve the above-described problems, the present invention provides an information input device including a moving body and an input device that inputs information using the moving body, wherein the moving body wirelessly communicates with the information input device by radio waves. A first wireless communication means for performing an ultrasonic signal output means for outputting an ultrasonic signal at a timing synchronized with a communication synchronization timing with the information input device by the first wireless communication means, A second wireless communication means for performing wireless communication with the first wireless communication means, an ultrasonic signal receiving means for receiving the ultrasonic signal, and a communication synchronization timing with the moving body by the second wireless communication means, It has a distance calculation means for measuring a time difference from the reception timing of the ultrasonic signal and calculating a distance to the moving body from the time difference. According to this configuration, the mobile body outputs an ultrasonic signal at a timing synchronized with the communication synchronization timing with the input device, and the input device has a time difference between the communication synchronization timing with the mobile body and the reception timing of the ultrasonic signal. And the distance to the moving body is calculated from this time difference, so that the distance to the moving body can be easily calculated.

  In the above configuration, the ultrasonic signal receiving unit includes a plurality of receiving units that receive the ultrasonic signals at different positions, and the distance calculating unit is configured to synchronize communication with the moving body by the second wireless communication unit. The time difference between the timing and the reception timing of the ultrasonic signals at the plurality of receiving units is respectively measured to calculate the distance between the moving body and the plurality of receiving units, and the position of the moving body is determined from these distances. You may make it calculate. The input device may include an output unit that outputs an output result of the distance calculation unit to a predetermined external device, and the second wireless communication unit outputs a calculation result of the distance calculation unit to a predetermined value. You may make it transmit to an external apparatus. Further, the input device may be configured as a timepiece having time measuring means for measuring time and display means for displaying the time measured by the time measuring means.

  According to another aspect of the present invention, there is provided a control method for an information input device including a mobile body and an input device for inputting information using the mobile body, wherein the input device establishes communication synchronization with the mobile body. A communication synchronization establishment step, a communication synchronization timing with the mobile body, and a time difference measurement step for measuring a time difference between a reception timing of an ultrasonic signal transmitted at a timing synchronized with the communication synchronization timing from the mobile body, A distance calculating step of calculating a distance from the time difference to the moving body. According to this configuration, the mobile body outputs an ultrasonic signal at a timing synchronized with the communication synchronization timing with the input device, and the input device has a time difference between the communication synchronization timing with the mobile body and the reception timing of the ultrasonic signal. And the distance to the moving body is calculated from this time difference, so that the distance to the moving body can be easily calculated. In the above configuration, in the time difference measurement step, a time difference between the communication synchronization timing with the mobile body and the reception timing of the ultrasonic signal at a plurality of positions is measured, and in the distance calculation step, a plurality of measured The distance between the moving body and the plurality of positions may be calculated from the time difference, and the position of the moving body may be calculated from the distances.

  Further, the present invention is applied to the information input apparatus and its control method described above, and a control program for carrying out the present invention is distributed to general users via an electric communication line, or such a program is It can also be implemented in such a manner that it is stored in a computer-readable recording medium such as a CD-ROM, floppy (registered trademark) disk, or optical recording disk and distributed to general users.

  In the present invention, the mobile body outputs an ultrasonic signal at a timing synchronized with the communication synchronization timing with the input device, and the input device measures the time difference between the communication synchronization timing with the mobile device and the reception timing of the ultrasonic signal. And since the distance to a mobile body is calculated from this time difference, the information of a mobile body can be input with a simple structure, without using optical communication.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an outline of an information input device according to the present embodiment. This information input device includes an input device 1 and a pen-type moving body 2, and the input device 1 is located on a personal computer (hereinafter referred to as a PC) 100 using the pen-type moving body 2. It is a device that functions as a so-called pointing device for inputting information (coordinate information). In this information input device, the pen-type moving body 2 is an operator that a user carries in a position designation operation and a writing operation, and is a short-range wireless such as Bluetooth (registered trademark) or a wireless LAN (Local Area Network). A function of communicating with the input device 1 by communication and a function of periodically transmitting the ultrasonic signal S1 are provided. Note that the transmission position of these signals is preferably a position that avoids a portion held by the user's hand. For example, as shown in FIG. 1, the ultrasonic signal S1 is transmitted from the front end side of the pen-type moving body 2, and the rear end side Is configured to transmit a wireless communication signal S2 for performing the short-range wireless communication.

  On the other hand, the input device 1 has a function of communicating with the pen-type moving body 2 by the short-range wireless communication and a function of receiving the ultrasonic signal S1, and the pen-type moving body is determined from the reception timing of the ultrasonic signal S1. 2 position is specified, and position information corresponding to this position is output to the PC 100 or the like. As shown in FIG. 1, in this embodiment, the input device 1 includes a main body case 3 and a band 4 for wearing on a user's body (arm), and is configured to be used as a wristwatch. The main body case 3 includes a display unit 5 that displays various types of information, a plurality of operating elements 6, and various connection terminals (not shown) as a configuration expressed in appearance. Here, as the connection terminal, for example, a terminal for charging the pen-type mobile body 2 and a terminal for connecting to an external device such as the PC 100 such as a USB (Universal Serial Bus) terminal are provided.

  The input device 1 is configured to receive the ultrasonic signal S1 at a remote position. In the present embodiment, when the main body case 3 is attached to the left hand and the pen-type moving body 2 is assumed to be gripped by the right hand, the position away from the right-side surface of the main body case 3 that becomes the surface of the pen-type moving body 2 side ( In FIG. 1, for example, ultrasonic reception antennas 31 </ b> A and 31 </ b> B, which will be described later, are arranged so as to receive the ultrasonic signal S <b> 1 at positions indicated by symbols A and B.

  FIG. 2 is a diagram showing a functional configuration of the input device 1. In the input device 1, the control unit 10 functions as a computer that controls the entire input device 1, and includes a CPU (Central Processing Unit) and the like. The storage unit 11 stores terminal identification information (terminal ID) of the pen-type moving body 2 assigned to the device 1 in addition to various control programs and data executed by the control unit 10.

  The wireless communication unit (second wireless communication means) 20 forms a communication service area of about several tens of meters in the surroundings by Bluetooth, wireless LAN, or the like under the control of the control unit 10, and a pen type in this communication service area. Other than the communication control unit 22 including an RF unit and a baseband unit for converting an analog reception signal received via the dedicated antenna 21 into a digital signal, for performing short-range wireless communication with the mobile body 2 and the like. In addition, the communication clock generator 23 for generating the communication clock f1 and the communication synchronous clock generation for generating the communication synchronization clock f2 for synchronizing the data transmission / reception timing (frame synchronization) with the pen-type moving body 2 Part 24 and the like. Here, when performing wireless communication with the pen-type mobile body 2, the wireless communication unit 20 refers to the terminal identification information stored in the storage unit 11, so that the pen-type movement assigned to the input device 1 is performed. Communicate with the body 2.

  The ultrasonic receiving units (ultrasonic signal receiving means) 30A and 30B receive the ultrasonic signals S1 transmitted from the pen-type moving body 2 via the ultrasonic receiving antennas 31A and 31B, respectively, and control the reception results. 10 is notified. The charging unit 40 functions as a charging means for charging the pen-type moving body 2. When it is detected that the pen-type moving body 2 is connected to a charging terminal (not shown), charging is performed via this terminal. Electric power is supplied to the pen-type moving body 2. Further, the charging unit 40 monitors the power source power of the pen-type moving body 2 (for example, the output voltage of the power storage unit 85 described later) to detect that the charging has been sufficiently performed and automatically ends the charging. . Thereby, overcharge of the electrical storage part 85 of the pen-type moving body 2 is avoided.

  The communication interface 50 functions as an output unit that outputs position information and the like to an external device such as the PC 100. For example, a USB (Universal Serial Bus) interface is applied. Here, the input device 1 is driven by a built-in battery (not shown). However, when a USB interface is applied to the communication interface 50, bus power is received from a device (such as the PC 100) connected to the USB interface. While the power is being supplied, the device 1 may be driven with bus power, or the bus power may be supplied to the pen-type moving body 2 as charging power. Thereby, when an external device is connected to the communication interface 50, the input device 1 can be used for a long time regardless of the remaining amount of the built-in battery of the input device 1.

  The time measuring unit 60 measures time and includes an oscillation circuit, a clock counter, a register, and the like. The display unit 5 displays the time measured by the time measuring unit 60 and various types of information under the control of the control unit 10, and includes, for example, a liquid crystal display panel and a liquid crystal driving circuit.

  On the other hand, in the pen-type moving body 2, the control unit 70 functions as a computer that controls the entire input device 1 and includes a CPU and the like. The storage unit 71 stores terminal identification information (terminal ID) of the input device 1 assigned to the own device 2 in addition to various control programs and data executed by the control unit 70.

  The wireless communication unit (first wireless communication means) 80 is for wireless communication with the input device 1 by Bluetooth, wireless LAN, or the like, and has a configuration substantially similar to that of the wireless communication unit 20 of the input device 1. That is, the radio communication unit 80 generates a communication clock f1 in addition to the communication control unit 82 including an RF unit and a baseband unit for converting an analog reception signal received via the dedicated antenna 81 into a digital signal. A communication clock generation unit 83, a communication synchronization clock generation unit 84 that generates a communication synchronization clock (communication synchronization signal) f2 for synchronizing data transmission / reception timing (frame synchronization) with the input device 1, and the like are provided. ing.

  The ultrasonic output unit (ultrasonic signal output unit) 90 transmits the ultrasonic signal S <b> 1 via the dedicated antenna 91 under the control of the control unit 70. The power storage unit 85 functions as a power source for the pen-type moving body 2, and a rechargeable battery is applied to be charged by the charging unit 40 of the input device 1.

  With the above configuration, in the pen-type moving body 2, when communication synchronization with the input device 1 is established by the wireless communication unit 80, the control unit 70 executes the control program stored in the storage unit 71. Accordingly, the ultrasonic output unit 90 outputs the ultrasonic signal S1 at a timing synchronized with the communication synchronization clock f2. Note that it is not preferable to continue to transmit the ultrasonic signal S1 even when the pen-type moving body 2 is not used, because the power consumption when not used (or during standby) increases. Therefore, a pen-type moving body 2 or an input device 1 may be provided with a termination stop operation element, and the transmission of the ultrasonic signal S1 may be stopped when this operation element is operated.

  Next, an operation when the input device 1 outputs position information to the PC 100 will be described. FIG. 3 is a flowchart showing the operation of the input apparatus 1 in this case. This operation is performed when the user operates the operation element 6 to switch the operation mode from the time display mode for displaying time to the operation mode for outputting coordinate information, or when the control unit 10 controls the communication interface 50. It is executed when it is detected that an external device is connected.

  First, the control unit 10 of the input device 1 performs a process of establishing communication synchronization with the pen-type moving body 2 assigned to the own device 1 (step S1). Here, the communication synchronization establishment process includes a process of synchronizing the communication synchronization clock f2 of the input device 1 and the communication synchronization clock f2 of the pen-type mobile body 2. For example, in the case of Bluetooth, in order to achieve synchronization in the piconet, that is, in accordance with the Bluetooth standard, the slave (pen-type moving body 2) is a Bluetooth clock (for example, the input device 1) of the master (input device 1). A fixed offset value (clock offset) is given to its own clock (communication clock f1) so as to synchronize with the master by referring to the communication synchronous clock f2), and the master and slave are common to each time slot. A numbering process is applied. As a result, the communication synchronization clock f2 of the input device 1 and the communication synchronization clock f2 of the pen-type mobile body 2 are synchronized, and the frame synchronization timing is determined with reference to this communication synchronization clock f2.

  Here, when communication synchronization is established between the input device 1 and the pen-type moving body 2, the ultrasonic signal S1 is output at a timing synchronized with the communication synchronization clock f2, as described above. In the present embodiment, as indicated by the symbol α in FIG. 4, the ultrasonic signal S1 is output at a timing t1 when a predetermined set time T0 has elapsed from the timing t0 of the communication synchronization clock f2. The set time T0 may be an arbitrarily set time, for example, zero.

  Next, the control unit 10 of the input apparatus 1 measures the time until the ultrasonic signal S1 is received by each of the ultrasonic receiving units 30A and 30B with reference to the communication synchronization clock f2 of the own apparatus 1 (step S2). ). More specifically, the control unit 10 starts counting the communication clock f1, for example, at the output timing (for example, the rising or falling timing) of the communication synchronous clock f2, and the ultrasonic receiving units 30A and 30B A process of obtaining the count values at the time when the ultrasonic signal S1 is received is performed.

  Next, the control unit 10 calculates the difference between these times (count values) and the set time T0 (prestored count value), that is, the propagation time of the ultrasonic signal S1 (step S3). The distance between the pen-type moving body 2 and the ultrasonic receiving antennas 31A and 31B is calculated from each propagation time (step S4). Then, the control unit 10 calculates the position of the pen-type moving body 2 by a well-known triangulation method based on these distances and the distance between the ultrasonic receiving antennas 31A and 31B stored in advance (step S4). The position information is output to the PC 100 via the communication interface 50 (step S5). This control part 10 repeats the process of said step S1-step S5 periodically. Thereby, the position information of the pen-type moving body 2 can be continuously output to the PC 100, and information on the position designation operation and writing operation by the user is input to the PC 100.

  As described above, according to the present embodiment, the pen-type moving body 2 transmits the ultrasonic signal S1 at the timing synchronized with the synchronization clock f2 for communication with the input device 1, so that the input device 1 is a pen-type device. The propagation time of the ultrasonic signal S1 can be easily acquired from the time difference between the communication synchronization timing with the mobile body 2 and the reception timing of the ultrasonic signal S1, and the calculation of the propagation distance and the position of the pen-type mobile body 2 can be easily performed. It can be carried out. Here, since the process of establishing this synchronization is a process included in the existing short-range wireless communication system, the wireless communication units 20 and 80 may use general-purpose short-range wireless communication modules, which is advantageous for cost reduction. It is.

  Furthermore, since only the ultrasonic signal S1 and the radio communication signal S2 using radio waves are transmitted and received between the input device 1 and the pen-type moving body 2, even if an arm or an object exists between them, the ultrasonic signal S1. And the wireless communication signal S2 are not blocked, and these signals have a wider directivity than in the case of optical communication. For this reason, an arm or an object may be interposed as compared with the conventional one that performs optical communication between the input device 1 and the pen-type moving body 2, and the position of the input device 1 and the pen-type moving body 2. The usage conditions are relaxed, such as the relationship is not limited, and it can be used in various situations.

  The above-described embodiments merely show one aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. For example, in the above-described embodiment, the case where the pen-type moving body 2 transmits the ultrasonic signal S1 at the timing synchronized with the synchronization clock f2 for communication with the input device 1 has been described. For example, the ultrasonic signal S1 may be transmitted at a timing synchronized with the frame synchronization timing with the input device 1.

  In the above-described embodiment, the operation area of the pen-type moving body 2 is set, and the position information of the pen-type moving body 2 is transmitted to the external device only when the pen-type moving body 2 is within the operation area. You may do it. Specifically, as shown in FIG. 5, after establishing communication synchronization with the pen-type moving body 2, first, an operation area setting process is performed to set an operation area (step S10). For example, as shown in FIG. 6, this operation area setting process is performed by a pen-type moving body 2 with a predetermined position of the operation area S (for example, the position of the corner of the operation area (reference point X1, reference point X2, or four corners). The position information of each position is acquired by designating the position, and an operation area (indicated by symbol S in FIG. 6) is set from the position information. Position information is calculated by the processes of steps S2 to S5 (step S11), and an instruction position determination process is performed to determine whether or not the coordinates of the position information are within the operation area S (step S12). If so, the position information is output to the external device only when the indicated position of the pen-type moving body 2 is in the operation area S (step S5). It is possible to prevent erroneous input of erroneous operation or location.

  In the above-described embodiment, the case where the input device 1 is formed in a wristwatch shape has been described. However, as shown in FIG. 7, the input device 1 is formed in a rectangular parallelepiped shape imitating a pen case, 2 may be detachably provided. According to this configuration, since the input device 1 and the pen-type moving body 2 are integrated, it is easy to carry. Further, the start of use of the pen-type moving body 2 is detected by detecting the removal of the pen-type moving body 2, and the above-described processing for outputting the position information of the pen-type moving body 2 is automatically executed. It is also possible to easily detect the end of use by wearing detection.

  Furthermore, in this embodiment, since the relative position of the pen-type moving body 2 with respect to the input device 1 is calculated, when the input device 1 is mounted on the arm, the position to be calculated changes even if the arm is moved. As shown in FIG. 8, when the pen-type moving body 2 is used, by fixing the input device 1 at a predetermined position, it is possible to avoid a case where the position information calculated by the position of the input device 1 moving changes. . Here, reference numerals A and B are examples of positions where the ultrasonic signal S1 is received, reference numeral 101 indicates a built-in battery (for example, a rechargeable battery), and reference numeral 102 indicates a terminal for connecting to an external device such as the PC 100. Is shown.

  In each of the above-described embodiments, the case where the input device 1 outputs position information has been described. However, the character recognition processing for recognizing a character from position information (coordinate information) when the pen-type moving body 2 is operated for writing. And character information (text data) may be output. Thereby, it becomes possible to input characters efficiently using the pen-type moving body 2. Further, the pen-type moving body 2 is provided with a specifying means (such as an operation switch) for specifying additional information such as a character color and line thickness, and the pen-type moving body 2 inputs the additional information by the wireless communication unit 80. You may make it transmit to the apparatus 1 wirelessly. As a result, the user can easily specify the color of the input character, the thickness of the line, and the like.

  Furthermore, in the above-described embodiment, the case where the input device 1 receives the ultrasonic signal S1 at two locations and calculates two-dimensional position information has been described. However, the input device 1 receives three-dimensional position information at three or more locations. Alternatively, it may be calculated, or only the distance between the input device 1 and the pen-type moving body 2 may be calculated by simply receiving at one place. In each of the above-described embodiments, the pen type moving body 2 is not limited to the pen type, and various shapes may be applied.

  In each of the above-described embodiments, the case where the position information or the distance information calculated by the input device 1 is output to an external device connected by a cable via the communication interface 50 has been described. However, the communication interface 50 is omitted, The wireless communication unit 20 may transmit position information or distance information to an external device. According to this configuration, the configuration of the input device 1 can be further simplified.

  In the above-described embodiment, the case where the present invention is applied to an information input device that inputs information to an external device has been described. However, the present invention is also applicable to the case where information is input only to the input device 1 by the pen-type moving body 2. The input device 1 may be widely applied to computers such as the PC 100, portable information processing devices such as PDAs (Personal Digital Assistants) and mobile phones.

  Further, in each of the above-described embodiments, a case has been described in which a control program for calculating the position and distance of the pen-type moving body 2 is stored in the input device 1 in advance. The program may be stored in a computer-readable recording medium such as a medium or a semiconductor recording medium, and the computer may read and execute the control program from the recording medium. The control program may be downloaded from a distribution server on the communication network.

It is a figure which shows the outline | summary of the information input device which concerns on this embodiment. It is a figure which shows the functional structure of an input device. It is a flowchart which shows operation | movement of an input device. It is a timing chart with which it uses for description of operation | movement of an input device. It is a flowchart which shows the modification of operation | movement of an input device. It is a figure for demonstrating the modification of an information input device. It is a figure for demonstrating the modification of an information input device. It is a figure for demonstrating the modification of an information input device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Input device, 2 ... Pen-type mobile body, 5 ... Display part, 6 ... Operator, 10, 70 ... Control part, 11, 71 ... Memory | storage part, 20, 80 ... Wireless communication part, 30A, 30B ... Super Sound wave receiving unit, 40 ... charging unit, 60 ... timing unit, 85 ... power storage unit, 90 ... ultrasonic wave output unit, 100 ... PC.

Claims (10)

In an information input device comprising a moving body and an input device for inputting information using the moving body,
The moving body is
First wireless communication means for performing wireless communication with the information input device by radio waves;
Ultrasonic signal output means for outputting an ultrasonic signal at a timing synchronized with a communication synchronization timing with the information input device by the first wireless communication means,
The input device is:
Second wireless communication means for performing wireless communication with the first wireless communication means;
The time difference between the ultrasonic signal receiving means for receiving the ultrasonic signal, the communication synchronization timing with the moving body by the second wireless communication means, and the reception timing of the ultrasonic signal is measured, and the movement is determined from this time difference. An information input device comprising distance calculation means for calculating a distance to the body. The ultrasonic signal receiving means includes a plurality of receiving units that receive the ultrasonic signals at different positions;
The distance calculation means measures the time difference between the communication synchronization timing with the mobile body by the second wireless communication means and the reception timing of the ultrasonic signal at the plurality of receiving sections, respectively, and the mobile body and the plurality The information input device according to claim 1, wherein a distance from the receiver is calculated, and a position of the moving body is calculated from the distance.   The information input device according to claim 1, wherein the input device includes an output unit that outputs an output result of the distance calculation unit to a predetermined external device.   The information input device according to claim 1, wherein the second wireless communication unit transmits a calculation result of the distance calculation unit to a predetermined external device.   The said input device is comprised as a timepiece which has a time measuring means which time-measures, and a display means which displays the time time-measured by this time measuring means. Information input device. In an information input device control method comprising a moving body and an input device that inputs information using the moving body,
The input device is:
Establishing communication synchronization with the mobile, communication synchronization establishing step;
A time difference measuring step for measuring a time difference between a communication synchronization timing with the mobile body and a reception timing of an ultrasonic signal transmitted at a timing synchronized with the communication synchronization timing from the mobile body;
And a distance calculating step of calculating a distance from the time difference to the moving body. In the time difference measurement step, each of the communication synchronization timing with the mobile body and the time difference between the reception timing of the ultrasonic signals at a plurality of positions are measured,
The distance calculation step calculates the distance between the moving body and the plurality of positions from the plurality of measured time differences, respectively, and calculates the position of the moving body from these distances. The control method of the information input device of description. In a control program for controlling, by a computer, an information input device including a moving body and an input device that inputs information using the moving body,
Allowing the input device to establish communication synchronization with the mobile;
Measuring the time difference between the communication synchronization timing with the mobile body and the reception timing of the ultrasonic signal transmitted at a timing synchronized with the communication synchronization timing from the mobile body,
A control program for calculating a distance to the moving body from the time difference. Let the input device measure the time difference between the communication synchronization timing with the moving body and the reception timing of the ultrasonic signal at a plurality of positions, respectively.
The control program according to claim 8, wherein distances between the moving body and the plurality of positions are respectively calculated from the plurality of measured time differences, and the position of the moving body is calculated from the distances.   10. A computer-readable recording medium on which the control program according to claim 8 or 9 is recorded.

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