WO2016042606A1 - Distance detection system - Google Patents

Distance detection system Download PDF

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Publication number
WO2016042606A1
WO2016042606A1 PCT/JP2014/074466 JP2014074466W WO2016042606A1 WO 2016042606 A1 WO2016042606 A1 WO 2016042606A1 JP 2014074466 W JP2014074466 W JP 2014074466W WO 2016042606 A1 WO2016042606 A1 WO 2016042606A1
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WIPO (PCT)
Prior art keywords
signal
transmission
terminal
distance
control signal
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PCT/JP2014/074466
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French (fr)
Japanese (ja)
Inventor
亮介 藤原
宮崎　祐行
片岸　誠
Original Assignee
株式会社日立製作所
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Priority to PCT/JP2014/074466 priority Critical patent/WO2016042606A1/en
Publication of WO2016042606A1 publication Critical patent/WO2016042606A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
    • G01S11/16—Systems for determining distance or velocity not using reflection or reradiation using difference in transit time between electrical and acoustic signals

Definitions

  • the present invention relates to a distance detection system that detects a distance to a target terminal.
  • a mobile body (corresponding to a “transmission terminal”) waits for a certain period of time before transmitting an ultrasonic signal, and only when an infrared signal originating from another mobile body is not received.
  • a mechanism for transmitting an ultrasonic signal is disclosed.
  • Patent Document 1 has the following problems.
  • the present application provides a distance detection system that can efficiently detect the distance between a transmission terminal and a reception terminal even when a plurality of transmission terminals and a plurality of reception terminals are operated simultaneously.
  • the distance detection system includes a transmission terminal and a reception terminal having the following processing units.
  • the transmission terminal controls (1) a transmission unit that transmits a distance measurement signal through the first medium, and (2) a second medium whose transmission speed is higher than the transmission speed of the first medium.
  • a transmission / reception unit that transmits and receives signals; and (3) transmission of the ranging signal is permitted when a control signal transmitted from another transmitting terminal is not received during a predetermined period Tc prior to transmission of the ranging signal.
  • a transmission terminal having a transmission control unit that transmits the control signal at regular intervals Ti ( ⁇ Tc) during the measurement period Tp from the transmission of the distance measurement signal.
  • a receiving terminal (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) a reception time of the ranging signal;
  • a receiving terminal having a timing detection unit that calculates a propagation time of the ranging signal based on a difference from the reception time of the control signal and detects a distance between the own terminal and the transmitting terminal;
  • it is a distance detection system composed of a transmission terminal and a reception terminal having the following processing units.
  • a transmission terminal (1) a transmission unit that transmits a distance measurement signal for distance measurement through a first medium, and a transmission unit that transmits a ranging signal spectrum-spread by a predetermined spreading sequence; 2) a transmission / reception unit that transmits / receives a control signal through a second medium having a transmission rate higher than the transmission rate of the first medium, the transmission / reception unit transmitting a control signal including spreading sequence information; and (3) the measurement A transmission control unit that allows transmission of the distance measurement signal when a control signal transmitted from another transmission terminal is not received during a predetermined period Tc prior to transmission of the distance signal.
  • the receiving terminal is (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) the ranging signal is used as a control signal.
  • the despreading process is performed using the included spreading sequence information, and the propagation time of the ranging signal is calculated based on the difference between the reception time of the ranging signal and the reception time of the control signal, and the distance between the own terminal and the transmitting terminal And a timing detection unit for detecting.
  • FIG. 1 is a diagram illustrating a schematic configuration of a distance detection system in Embodiment 1.
  • FIG. 3 The figure explaining schematic structure of the position detection system which uses the distance detection system shown in FIG.
  • FIG. 3 is a chart showing an example of a medium applicable to the first embodiment.
  • FIG. 3 is a diagram illustrating a configuration example of a transmission terminal according to the first embodiment.
  • the flowchart which shows the operation example of the transmission terminal at the time of ranging signal transmission.
  • FIG. 3 is a diagram illustrating a configuration example of a receiving terminal according to the first embodiment.
  • 3 is a diagram illustrating a configuration example of a timing detection unit of a receiving terminal in Embodiment 1.
  • FIG. 3 is a flowchart illustrating an operation example of the receiving terminal when receiving a control signal in the first embodiment.
  • FIG. 3 is a diagram illustrating an example of a distance measurement sequence according to the first embodiment.
  • FIG. 3 is a chart illustrating an example of information included in a control signal according to the first embodiment.
  • FIG. The figure explaining the other schematic structure of the position detection system using the distance detection system shown in FIG. 10 is a flowchart illustrating an operation example of a transmission terminal according to the second embodiment. 9 is a flowchart illustrating an operation example of a receiving terminal according to the second embodiment.
  • FIG. 10 is a diagram illustrating an example of a distance measurement sequence according to the second embodiment.
  • FIG. 6 is a chart showing an example of information included in an ACK signal of Embodiment 2.
  • FIG. 10 is a diagram illustrating an example of information included in a control signal according to the third embodiment. 9 is a flowchart illustrating a necessary standby time calculation procedure when a control signal of a transmitting terminal is detected in the third embodiment.
  • FIG. 10 is a diagram illustrating an example of a distance measurement sequence according to the third embodiment.
  • FIG. 10 is a diagram illustrating a configuration example of an ultrasonic transmission unit of a transmission terminal according to a fourth embodiment.
  • FIG. 10 is a diagram illustrating a configuration example of a receiving terminal according to a fourth embodiment.
  • FIG. 10 is a diagram illustrating a configuration example of a timing detection unit of a receiving terminal according to a fourth embodiment.
  • FIG. 10 is a diagram illustrating a distance measurement sequence example (part 1) according to the fourth embodiment.
  • FIG. 12 is a diagram illustrating a distance measurement sequence example (part 2) according to the fourth embodiment.
  • FIG. 10 is a chart showing an example of information included in a control signal in Embodiment 4.
  • FIG. 10 is a diagram illustrating an example of a frequency estimation waveform decoded by despreading processing according to the fourth embodiment.
  • FIG. 10 is a diagram illustrating a configuration example of a receiving terminal according to a fifth embodiment.
  • FIG. 10 is a diagram illustrating a configuration example of a timing / phase difference detection unit of a receiving terminal according to a fifth embodiment.
  • FIG. 1 shows a schematic configuration of the distance detection system according to the present embodiment.
  • the distance detection system shown in FIG. 1 includes a receiving terminal 1 and transmitting terminals 2A and 2B.
  • the receiving terminal 1 measures the propagation times of signals transmitted from the transmitting terminals 2A and 2B, and measures the distance d1 between the receiving terminal 1 and the transmitting terminal 2A and the distance d2 between the receiving terminal 1 and the transmitting terminal 2B.
  • FIG. 1 shows the case where there are two transmission terminals, the number of transmission terminals may be one or three or more.
  • FIG. 2 shows a schematic configuration example of the position detection system according to the present embodiment.
  • the position detection system shown in FIG. 2 includes receiving terminals 1A and 1B, transmitting terminals 2A and 2B, and a positioning device 3.
  • This position detection system is based on a set of distances d11 and d12 or d21 and d22 measured using the distance detection system shown in FIG. 1 on a coordinate system defined by the receiving terminals 1A and 1B.
  • the relative positions of the transmitting terminals 2A and 2B are detected. In the case of FIG.
  • the coordinate system is given by an axis (y axis) connecting the receiving terminals 1A and 1B and an axis (x axis) passing through the midpoint position of the receiving terminals 1A and 1B and orthogonal to the y axis.
  • the method of determining the coordinate system is not limited to the example of FIG.
  • the two receiving terminals 1A and 1B are installed at coordinates S1 and S2 on the y-axis.
  • the receiving terminal 1A measures the distance d11 between the transmitting terminal 2A and the distance d21 between the transmitting terminal 2B.
  • the receiving terminal 1B measures the distance d12 to the transmitting terminal 2A and the distance d22 to the transmitting terminal 2B.
  • the positioning device 3 calculates the coordinates P1 (x1, y1) of the transmission terminal 2A based on the distances d11 and d12, and calculates the coordinates P2 (x2, y2) of the transmission terminals 2B based on the distances d21 and d22.
  • FIG. 3 shows medium combination candidates.
  • the distance measurement signal medium a medium having a slower propagation speed than the control signal medium is used.
  • ultrasonic waves are used as the distance measurement signal medium
  • radio waves radio waves
  • the gist of the invention described in this specification is not limited to the type of medium.
  • FIG. 4 shows an example of the functional configuration of the transmission terminal.
  • the transmission terminal includes a control unit 11, an ultrasonic transmission control unit 12, a wireless transmission control unit 13, a control signal detection unit 14, an ultrasonic transmission unit 15, a wireless transmission / reception unit 16, an ultrasonic conversion element 17, and a wireless conversion element 18. .
  • the transmission terminal also includes various sensors 19 as necessary. Among these, the ultrasonic transmission control unit 12, the ultrasonic transmission unit 15, and the ultrasonic transducer 17 are used for transmitting a distance measurement signal.
  • the wireless transmission control unit 13, the control signal detection unit 14, the wireless transmission / reception unit 16, and the wireless conversion element 18 are used for transmission / reception of control signals.
  • the ultrasonic transducer 17 is an element (for example, an ultrasonic sensor) that converts an electrical signal into an ultrasonic signal.
  • the wireless conversion element 18 is an element (for example, an antenna) that mutually converts an electrical signal and a wireless signal.
  • a conversion element suitable for the medium to be used is used.
  • the ultrasonic transmission unit 15 generates a modulation signal under the control of the ultrasonic transmission control unit 12.
  • the ultrasonic transducer 17 radiates an ultrasonic signal obtained by converting the modulation signal into space.
  • the wireless transmission / reception unit 16 includes a wireless signal transmission function unit and a reception function unit.
  • the reception function unit of the wireless transmission / reception unit 16 processes the reception signal converted into an electric signal by the wireless conversion element 18 and supplies the received signal to the control signal detection unit 14 as reception data.
  • the control signal detection unit 14 detects the input of received data and gives it to the control unit 11.
  • the wireless transmission control unit 13 performs communication control such as generating transmission data and giving it to the wireless transmission / reception unit 16.
  • the transmission function unit of the radio transmission / reception unit 16 modulates transmission data into a transmission signal suitable for transmission of a radio signal.
  • the wireless conversion element 18 radiates a wireless signal corresponding to the transmission data into space.
  • the control unit 11 performs timing control for the entire transmission terminal.
  • FIG. 5 shows an example of the operation of the transmitting terminal when transmitting a ranging signal.
  • FIG. 5 shows an operation in the case of transmitting a distance measurement signal periodically (cycle Tr seconds).
  • Tr seconds After Tr seconds have passed since the transmission of the previous transmission signal (S1), the control unit 11 checks whether a control signal from another transmission terminal is received by the wireless transmission / reception unit 16 for a certain period (Tc seconds). (S2, S3). If the control signal is received within the same time, the control unit 11 calculates the time to wait and enters a state of waiting for the calculated time (S7). When the standby time has elapsed, the control unit 11 returns to S2, and again returns to a state of waiting for reception of a control signal from another transmission terminal.
  • the standby time is a time during which the ranging signal transmitted from the transmission terminal that is the transmission source of the received control signal may collide with the ranging signal transmitted from the terminal itself.
  • the waiting time is calculated based on the remaining measurement period length included in the received control signal. Note that if this waiting time is given a value or randomness that is unique to the transmitting terminal, even if there are three or more transmitting terminals, the determination period of whether transmission is possible or not will be shifted in each transmitting terminal. Distance signal collision can be effectively avoided.
  • the control unit 11 transmits the distance measurement signal through the ultrasonic transmission unit 15 and the ultrasonic transducer 17 (S4). Simultaneously with this transmission, the control unit 11 also transmits a control signal through the wireless transmission / reception unit 16 and the wireless conversion element 18 (S5). Thereafter, the control unit 11 intermittently transmits the control signal periodically (every Ti seconds) until Tp seconds elapse after transmission of the control signal transmitted simultaneously with the ranging signal (S5, S6, S8). After the lapse of Tp seconds, the control unit 11 stops transmitting the control signal and waits until the next transmission time (S1).
  • the control signal is received for only Tc seconds for avoiding the collision of the distance measurement signal, so that the distance between the distance measurement signals transmitted from other transmission terminals is
  • the power consumption can be reduced as compared with the case of waiting for the control signal during the entire period during which the collision may occur.
  • FIG. 6 shows a functional configuration example of the receiving terminal.
  • the receiving terminal includes an ultrasonic transducer 17, a radio transducer 18, an ultrasonic receiver 21, a wireless transmitter / receiver 22, a timing detector 23, a controller 24, and a data processor 25.
  • the ultrasonic transducer 17, the ultrasonic receiver 21, and the timing detector 23 are used for receiving ranging signals.
  • the wireless conversion element 18 and the wireless transmission / reception unit 22 are used for transmission / reception of control signals.
  • the wireless transmission / reception unit 22 demodulates the electrical signal converted from the wireless signal by the wireless conversion element 18 and notifies the control unit 24 of data such as a control signal.
  • the ultrasonic receiving unit 21 performs amplification processing and filter processing (analog processing) on the electrical signal converted from the ultrasonic signal in the ultrasonic transducer 17 and transmits the amplified signal to the timing detection unit 23.
  • the control unit 24 provides the timing detection unit 23 with the remaining measurement period length of the ranging signal and the transmission time information of the ranging signal included in the control signal.
  • the timing detector 23 detects the propagation time of the distance measurement signal. In addition, the timing detection unit 23 also detects a frequency shift of the received ranging signal at the time of the detection.
  • FIG. 7 shows a configuration example of the timing detection unit 23.
  • the sampling unit 31 performs sampling only during the measurement period Tp provided from the control unit 24.
  • the frequency estimation unit 32 receives the data sampled by the sampling unit 31 and estimates the frequency shift amount of the carrier frequency.
  • the time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal. For example, when the first control signal (control signal transmitted at the same time as the ranging signal) is received, the reception time difference between the ranging signal and the control signal corresponds to the propagation time of the ranging signal as it is. On the other hand, when the second control signal is received without receiving the first control signal, the transmission time of the distance measurement signal is calculated from the information included in the control signal, and the reception time difference (the second control signal The propagation time of the distance measurement signal is calculated based on the difference between the reception time and the reception time of the distance measurement signal) and the transmission time of the distance measurement signal. Specifically, the time difference between the transmission time of the distance measurement signal and the reception time of the second control signal and the reception time difference (the difference between the reception time of the second control signal and the reception time of the distance measurement signal) Calculate the sum.
  • the transmission time of the distance measurement signal can be obtained from the transmission time information of the distance measurement signal added to the control signal, for example.
  • the transmission time of the first control signal can be calculated from the sequence number added to the control signal. Whether the control signal is the first signal or the second signal transmitted with respect to the same distance measurement signal is known from the sequence number of the control signal included in the control signal. Even when the received control signal is the third and subsequent control signals, the propagation time of the ranging signal can be detected by the same method as described above.
  • the data processing unit 25 converts the propagation time obtained by the timing detection unit 23 into the propagation distance of the distance measurement signal. Further, the data processing unit 25 calculates the relative speed from the frequency shift amount according to the principle of Doppler shift as necessary. In addition, the data processing unit 25 transmits the data to other devices (including the transmission terminal and the reception terminal) together with ID information of the transmission terminal as necessary.
  • FIG. 8 shows an operation example of the receiving terminal when receiving the control signal.
  • the control unit 24 that has received the control signal determines whether or not the signal is a control signal for a new ranging signal (S11). If the received control signal is a signal for a distance measurement signal that is the same as the control signal that has already been received, since the reception process of the distance measurement signal has already been started, the control unit 24 does nothing.
  • the ranging signal corresponding to the control signal can be confirmed by, for example, the sequence number of the ranging signal included in the control signal.
  • the control unit 24 gives timing information to the timing detection unit 23, and samples the ultrasonic signal for a certain time (S12).
  • the sampling time is from the time when the control signal is received to the time when the ultrasonic ranging signal may arrive.
  • the time at which the ultrasonic ranging signal may reach is preferably included in the measurement period information in the control signal.
  • the timing detection unit 23 measures the propagation time of the distance measurement signal based on the sampled data (S13), and calculates the distance to the transmission terminal from the value (S14).
  • the receiving terminal can know the transmission time of the distance measuring signal and can immediately measure the distance.
  • the signal propagation time can be measured. That is, in the method of the present embodiment, if any one of a plurality of control signals can be received, the propagation time of the ranging signal can be measured.
  • FIG. 9 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having the communication function described above.
  • FIG. 9 is based on the distance detection system shown in FIG. 1 and shows that the transmission terminal 2B is about to transmit a distance measurement signal while the transmission terminal 2A is transmitting the distance measurement signal. Represents. Since the transmission terminal 2B receives the control signal from the transmission terminal 2A during the control signal standby operation (S2, S3) described above, the transmission terminal 2B waits for the necessary waiting time (S7), and the measurement period of the transmission terminal 2A ends. After that, send a confidence ranging signal. The receiving terminal 1 receives the ranging signal only during the measurement period (Tp seconds) indicated in the control signal from the time when the control signal is received, and detects its propagation time.
  • Tp seconds the measurement period indicated in the control signal
  • FIG. 10 shows an example of suitable information included in the control signal transmitted from the transmitting terminal to the receiving terminal.
  • FIG. 10 shows a case where the control signal includes a unique identification number (ID) of the transmission terminal, a ranging signal sequence number, a control signal sequence number, ranging signal transmission time information, and a remaining measurement period length.
  • ID unique identification number
  • the control signal includes a unique identification number (ID) of the transmission terminal, a ranging signal sequence number, a control signal sequence number, ranging signal transmission time information, and a remaining measurement period length.
  • ID unique identification number
  • ranging signal sequence number a control signal sequence number
  • ranging signal transmission time information a remaining measurement period length
  • remaining measurement period length It is an example.
  • other correction information can be added to the control signal.
  • the receiving terminal uses the received temperature as a correction value when calculating the distance.
  • acceleration data, azimuth data, angular velocity data, and the like may be included in the control signal as sensor information that can be used when calculating the distance or position. Note that it is not necessary to include all the information illustrated in FIG. 10 in the control signal, and only a part of the information may be included in the control signal.
  • FIG. 11 The position detection system shown in FIG. 11 is a case where the transmitting terminal is a fixed station.
  • each of the two transmitting terminals 1C and 1D transmits their relative position information included in the control signal
  • each of the receiving terminals 1C and 1D transmits the propagation time of the ranging signal received from each transmitting terminal ( Measure the conversion distance.
  • Each receiving terminal calculates the position of the receiving terminal with respect to the transmitting terminals 1C and 1D based on the measurement distance between the transmitting terminals 1C and 1D and the information on the relative position of the transmitting terminal.
  • the distance detection system (FIG. 1) and position detection system (FIGS. 2 and 11) described above can be used in a space where a plurality of transmission terminals and a plurality of reception terminals are operated simultaneously. Further, as described above, the distance detection system according to the embodiment can shorten the standby time before the start of distance measurement, and can increase the number of measurements. Further, by shortening the control signal waiting period Tc in the transmitting terminal, it is possible to suppress power consumption required for the waiting. Furthermore, in the distance detection system according to the present embodiment, even if reception of the first control signal fails due to transmission of a plurality of control signals, distance detection is possible with the second and subsequent control signals, and the measurement frequency is increased. be able to. As a result, a distance detection system and a position detection system with high reliability of the measured distance and position can be realized.
  • Example 2 a system in which a trigger signal (for example, an ACK signal) time-division multiplexed from the receiving terminal side to the transmitting terminal side is transmitted by an infrared signal is considered.
  • a trigger signal for example, an ACK signal
  • Patent Document 1 When the technique described in Patent Document 1 is applied to the system, a collision between a plurality of trigger signals transmitted from a plurality of receiving terminals operating independently from each other, a trigger signal transmitted from the receiving terminal, and a transmitting terminal The collision of the ultrasonic signal transmitted from will occur.
  • the distance detection system and the position detection system assumed in this embodiment are the same as the distance detection system (FIG. 1) and the position detection system (FIGS. 2 and 11) described in the first embodiment.
  • the configurations of the transmission terminal and the reception terminal that constitute the system are the same as those in the first embodiment.
  • radio radio wave
  • FIG. 12 shows an operation example of the transmission terminal used in this embodiment.
  • parts corresponding to those in FIG. are that in the determination process executed following the control signal waiting step (S2) for Tc seconds, in addition to the control signals from other transmitting terminals, An operation for detecting an ACK signal from the terminal is also executed (S21).
  • Another difference is that an ACK signal from the receiving terminal is received after transmission of the control signal (S5) (S22).
  • Other operations are similar to the operation example shown in FIG.
  • FIG. 13 shows an operation example of the receiving terminal used in this embodiment.
  • parts corresponding to those in FIG. 8 are given the same reference numerals.
  • One of the differences between the operation shown in FIG. 13 and the operation shown in FIG. 8 is that, after receiving the control signal, the step of transmitting the ACK signal (S31) is executed in parallel with the reception process (S11 and subsequent steps). Note that the transmission of the ACK signal is performed after waiting for a waiting time unique to the receiving terminal or a random time. Thereby, even when there are a plurality of receiving terminals in the same space, collision of ACK signals transmitted from the plurality of receiving terminals can be prevented.
  • Another difference is that a step (S32) of transmitting an ACK signal reflecting the result of distance calculation by receiving the distance measurement signal to the corresponding transmitting terminal is added.
  • FIG. 14 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having a communication function according to the present embodiment.
  • FIG. 14 assumes a case where the two transmission terminals 2A and 2B transmit distance measurement signals to the two reception terminals 1A and 1B, respectively, as in the position detection system shown in FIG. This shows that each of the two receiving terminals 1A and 1B that have received the control signal from the transmitting terminal 2A is returning an ACK signal during the distance measurement period of the transmitting terminal 2A.
  • a terminal-specific waiting time or a random waiting time is provided in each of the receiving terminals 1A and 1B.
  • the transmitting terminal 2B is in a state of attempting to transmit a ranging signal during the measuring period of the transmitting terminal 2A, but transmitted from the transmitting terminal 2A during the measuring period (Tp seconds). Since the control signal has been received, transmission of the distance measurement signal of the own terminal is waited until the distance measurement sequence of the transmission terminal 2A is completed.
  • the transmission terminal 2B that cannot receive the control signal of the transmission terminal 2A There is a possibility that the signal transmission sequence starts immediately.
  • the transmitting terminal 2B knows that it is during the measurement period of the transmitting terminal 2A in the hidden terminal state by receiving the ACK signal transmitted by the receiving terminal even if it cannot receive the control signal, Transmission of the ranging signal can be waited until the end of the measurement period.
  • FIG. 15 shows an example of suitable information included in the ACK signal.
  • FIG. 15 shows an example in which the ACK signal includes the remaining measurement period length, the distance or position measurement result (latest value) calculated immediately before transmission of the ACK signal, and the relative speed measurement result.
  • the remaining measurement period length is calculated based on the remaining measurement period length included in the control signal received from the transmission terminal.
  • FIG. 16 shows a distance measurement sequence example of distance or position (latest value) and relative speed measurement results.
  • the transmitting terminal 2A (2B) determines the current distance measurement from the distance or position measurement result measured in the distance measurement sequence immediately before the ACK signal or the distance measurement sequence up to the previous time and the relative speed result.
  • the propagation time of the distance measurement signal in the sequence is estimated, and information on the measurement period necessary for receiving the distance measurement signal is included in the control signal and transmitted.
  • the receiving terminal 1A (1B) can shorten the measurement period of the distance measurement signal coming from now.
  • the other transmission terminal that has received the control signal can also know the shortened measurement period, and after receiving the control signal transmitted from the other transmission terminal
  • the waiting time to be provided can be optimized. For example, in the case of Example 1, the measurement period is uniformly set to the measurement period (Tpmax in FIG. 16) assuming the maximum detection distance. For this reason, when the distance between the transmission terminal and the reception terminal is short, useless measurement time occurs.
  • the transmitting terminal can know whether or not the distance measurement has succeeded by transmitting an ACK signal from the receiving terminal, thereby realizing a more robust distance detection system and position detection system. it can.
  • the distance measurement signal propagation time in the next distance measurement sequence is transmitted by including the distance measurement result and the relative speed result in the previous distance measurement sequence in the ACK signal and transmitting them to the transmitting terminal. Can be estimated in advance, and the measurement period can be reduced and the number of measurements per unit time can be increased accordingly.
  • radio radio
  • FIG. 17 shows an example of information included in the control signal. The difference from the case of the first embodiment shown in FIG. 10 is that the estimated propagation time information (the estimated arrival time at the receiving terminal 1, the estimated arrival time at the receiving terminal 2, and the estimated arrival time at the receiving terminal 3) is included. .
  • FIG. 18 shows an operation example of the transmission terminal used in this embodiment.
  • the processing shown in FIG. 18 is executed in the calculation of the necessary standby time and the standby step (S7) in FIG.
  • the control unit 11 receives the distance measurement signal transmitted from the other transmission terminal. The time is estimated based on the propagation time information included in the received control signal and the transmission time information of the ranging signal (S41).
  • the control unit 11 estimates the propagation time of its own ranging signal based on the distance measurement result or position measurement result between itself and the receiving terminal, or the relative velocity measurement result between itself and the receiving terminal ( S42).
  • the control unit 11 calculates a standby time required for transmission of its own ranging signal based on the values obtained in S41 and S43 (S43).
  • FIG. 19 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having a communication function according to this embodiment.
  • FIG. 19 assumes a case in which two transmission terminals 2A and 2B transmit distance measurement signals to one reception terminal 1 as in the position detection system shown in FIG.
  • the transmission terminal 2B tries to transmit the distance measurement signal during the measurement period of the distance measurement signal of the transmission terminal 2A, but the control signal derived from the transmission terminal 2A is detected.
  • the receiving terminal 2B determines that there is no collision even if it immediately transmits a distance measurement signal according to the above-described procedure, and starts transmitting its distance measurement signal without waiting for the end of the measurement period Tp. .
  • the receiving terminal does not wait for the end of the measurement period Tp secured for the distance measurement of the other transmission terminal, and its own distance measurement signal. Can be sent. As a result, the number of measurements per unit time can be increased.
  • Example 4 In the present embodiment, a case where a spread spectrum technique is applied to transmission of a ranging signal will be described.
  • FIG. 20 shows a functional configuration of the ultrasonic transmission unit 15 of the transmission terminal used in this embodiment.
  • the ultrasonic transmission unit 15 in this embodiment includes a diffusion processing unit 41, a modulation unit 42, and a drive circuit unit 43.
  • the spread processing unit 41 generates a spread pulse train such as an M sequence or a Gold code.
  • the modulator 42 modulates the spread pulse train with a desired carrier frequency.
  • the modulation method is not limited to BPSK, QPSK, MSK, or the like.
  • the generated modulation signal is radiated to the space through the driving of the ultrasonic transducer 17 by the drive circuit unit 43.
  • the radio transmission control unit 13 in the present embodiment includes the spreading sequence information when generating control signal data.
  • Other operations of the transmitting terminal are the same as those of the transmitting terminal in the above-described embodiment.
  • FIG. 21 shows a configuration example of the receiving terminal used in this embodiment.
  • the control unit 52 When receiving the control signal, the control unit 52 provides the timing detection unit 51 with the measurement period of the distance measurement signal extracted from the control signal and the transmission time of the distance measurement signal. At the same time, the control unit 52 extracts spreading sequence information from the control signal and provides it to the timing detection unit 51.
  • the timing detection unit 51 calculates the propagation time of the distance measurement signal based on the measurement period and the distance measurement signal transmission time. At that time, it is also possible to detect a frequency shift.
  • FIG. 22 shows a functional configuration of the timing detection unit 51.
  • the sampling unit 31 samples the received signal only during the measurement period provided from the control unit 52.
  • the frequency estimation / correlation unit 61 performs a frequency shift estimation process and a despreading process on the sampled data.
  • a spreading sequence used in the despreading process is provided from the control unit 52.
  • the time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal.
  • Other operations of the receiving terminal are the same as those of the above-described embodiment.
  • FIG. 23 shows an example of a distance measuring sequence realized in this embodiment.
  • FIG. 23 is based on the distance detection system shown in FIG. 1, and shows a case where two transmission terminals 2 ⁇ / b> A and 2 ⁇ / b> B transmit ranging signals to one reception terminal 1.
  • the reception terminal 1 waits for the distance measurement signal using the spreading sequence ⁇ Ai ⁇ included in the control signal, and obtains the propagation time of the received distance measurement signal.
  • the receiving terminal 1 waits for a ranging signal using the spreading sequence ⁇ Bi ⁇ included in the control signal, and obtains the propagation time of the received ranging signal.
  • FIG. 24 shows an example of the sequence.
  • the transmission terminals 2A and 2B transmit the control signal only once for transmission of the distance measurement signal.
  • the control signal includes each spreading sequence.
  • the receiving terminal 1 performs reception processing with the spreading sequence included in the control signal in each measurement period.
  • the two ranging signals can be received separately even if the reception timings of the two ranging signals at the receiving terminal collide in time. Even when the measurement signals of the ranging signals from a plurality of transmission terminals overlap in time, if the frequency estimation / correlation unit 61 includes a plurality of despreading circuits in parallel, each ranging signal is calculated simultaneously. be able to. Even when the frequency estimation / correlation unit 61 includes only one despreading circuit, the sampling data is accumulated in a storage area (not shown), and after each measurement period, the inverse of the sampling data is performed. If the spreading process is executed in time sequence, it is possible to obtain the reception times of ranging signals having different spreading sequences. In FIG. 24, the control signal is transmitted only once. However, assuming that the first control signal cannot be received by the receiving terminal 1, the control signal is transmitted a plurality of times (at least twice). Also good.
  • FIG. 25 shows an example of information suitable for inclusion in a control signal transmitted from a transmitting terminal to a receiving terminal.
  • FIG. 25 differs from the example shown in FIG. 10 in that spreading sequence information is included in the control signal.
  • FIG. 26 shows waveform examples related to frequency shift amount estimation processing and despreading processing executed by the frequency estimation / correlation unit 61.
  • the waveform shown in the upper part of FIG. 26 shows a spread pulse sequence. However, this waveform is an unmodulated baseband signal.
  • the waveform shown in the middle stage is a waveform obtained after convolution with a reference pulse train having the same spreading sequence. In this example, it is assumed that there is no frequency shift. A peak appears when the timings of the spreading sequences match, and this is the calculation result of the despreading process.
  • the waveform shown in the lower part is a plot of the result of calculating the peak value of the above despreading process by offsetting the carrier frequency of the reference signal.
  • a peak appears at a frequency offset of 0.
  • the frequency shift amount and the propagation delay amount can be calculated by the signal processing described above.
  • Example 5 In this embodiment, a system including a receiving terminal having an angle detection function will be described. Specifically, an example will be described in which two ultrasonic transducers are mounted on one receiving terminal and an angle detection function for estimating the azimuth of the transmitting terminal relative to the receiving terminal from the phase difference of the received signals.
  • the distance detection system and the position detection system assumed in this embodiment are the same as the distance detection system (FIG. 1) and the position detection system (FIGS. 2 and 11) described in the first embodiment.
  • the configuration of the transmission terminal that constitutes the system is the same as in the first to fourth embodiments. However, in the following description, the transmission terminal will be described with respect to the transmission terminal described in the fourth embodiment (that is, a terminal equipped with a function of transmitting a ranging signal using a spread sequence).
  • the difference from the above-described embodiment is the configuration of the receiving terminal.
  • FIG. 27 shows a configuration example of the receiving terminal used in this embodiment.
  • the receiving terminal in this embodiment includes two ultrasonic transducers 17A and 17B, one radio transducer 18, two ultrasonic receivers 21A and 21B, one radio transmitter / receiver 22, a timing / phase difference detector 71, A control unit 52 and a data processing unit 72 are included.
  • the ultrasonic conversion elements 17A and 17B, the wireless conversion element 18, the ultrasonic reception circuits 21A and 21B, the wireless transmission / reception unit 22, and the control unit 52 perform the same processing as each component of the reception terminal of the fourth embodiment. Execute.
  • FIG. 28 shows a functional configuration of the timing / phase difference detection unit 71.
  • the timing / phase difference detection unit 71 includes two sampling units 31A and 31B, a despreading unit 81, a frequency estimation / correlation unit 61, a phase difference detection unit 82, and a time difference detection unit 33.
  • Sampling units 31 ⁇ / b> A and 31 ⁇ / b> B both sample the received signal during the measurement period provided from control unit 52.
  • the frequency estimation / correlation unit 61 inputs the sampling data sampled by the sampling unit 31B, and executes carrier frequency deviation estimation processing and despreading processing on the sampling data. Note that the spreading sequence used in the despreading process is provided from the control unit 52.
  • the time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal.
  • the despreading unit 81 uses the frequency offset obtained by the frequency estimation / correlation unit 61 to despread the sampling data input from the sampling unit 31A.
  • the phase difference detection unit 82 calculates the phase difference (arrival time difference) of the received signals based on the results obtained by the despreading unit 81 and the frequency estimation / correlation unit 61.
  • the data processing unit 72 executes processing for converting the time information calculated by the timing / phase difference detection unit 71 into the propagation distance of the ranging signal.
  • the data processing unit 72 converts the phase difference information obtained by the phase difference detection unit 82 into the arrival direction of the distance measurement signal.
  • the data processing unit 72 calculates the relative speed of the transmitting terminal with respect to the receiving terminal from the frequency estimation value based on the principle of Doppler shift. Furthermore, if necessary, the data processing unit 72 transmits these data together with ID information to other terminals.
  • the arrival direction of the distance measurement signal can be detected with a simple receiver configuration at the same time as the distance. Therefore, in the distance detection system configuration shown in FIG. 1, even when there is only one receiving terminal, it is possible to estimate the position of the transmitting terminal with respect to the receiving terminal. Further, even when there are two or more receiving terminals as in the position detection system shown in FIG. 2, it is possible to improve the success probability of position detection and improve the position detection accuracy.
  • the present invention is not limited to the configuration of the embodiment described above, and includes various modifications.
  • some embodiments are described in detail, and it is not always necessary to include all the configurations described.
  • a part of one embodiment can be replaced with a part of the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
  • each of the above-described configurations, functions, processing units, processing means, and the like may be partly or entirely realized as, for example, an integrated circuit or other hardware.
  • Each of the above-described configurations, functions, and the like may be realized by a processor interpreting and executing a program that realizes each function. That is, each configuration may be realized by software.
  • information such as programs, tables, and files for realizing each function can be stored in a storage device such as a memory, a hard disk, an SSD (Solid State Drive), or a storage medium such as an IC card, an SD card, or a DVD.
  • control lines and information lines indicate what is considered necessary for explanation, and do not represent all control lines and information lines necessary for the product. In practice, it can be considered that almost all components are connected to each other.

Abstract

A transmission terminal has (1) a transmission unit for transmitting a distance measurement signal for measuring a distance through a first medium, (2) a transmission and reception unit for transmitting and receiving a control signal through a second medium having a transmission speed faster than that of the first medium, and (3) a transmission control unit for allowing the transmission of the distance measurement signal and causing the control signal to be transmitted at each prescribed interval Ti (<Tc) during a measurement interval Tp from the transmission of the distance measurement signal if during a prescribed period Tc before the transmission of the distance measurement signal, there is no reception of a control signal transmitted from another transmission terminal. A reception terminal has (1) a reception unit for receiving the distance measurement signal through the first medium, (2) a transmission and reception unit for transmitting and receiving the control signal through the second medium, and (3) a timing detection unit for calculating the propagation time of the distance measurement signal on the basis of the difference between the reception time of the distance measurement signal and the reception time of the control signal and detecting the distance between the reception terminal and the transmission terminal.

Description

距離検知システムDistance detection system
　本発明は、対象端末との間の距離を検知する距離検知システムに関する。 The present invention relates to a distance detection system that detects a distance to a target terminal.
　現在、超音波信号と電波信号（又は赤外線信号）の各伝搬時間を測定し、その時間差に基づいて送信端末と受信端末との間の距離を検出するシステムが提案されている。このシステムは、電波信号（又は赤外線信号）は光速で伝搬する一方、超音波信号は光速よりも遅く伝搬することに着目し、２つの信号の到着時間差が超音波信号の伝搬時間にほぼ一致するとみなして端末間の距離を測定する。ところで、上記システムの運用時には、超音波信号を送信する送信端末が空間内に同時に複数存在する場合が考えられる。このような場合、距離の測定には、各送信端末を識別する技術が必要とされる。例えば特許文献１には、移動体（「送信端末」に相当する。）が超音波信号を送信する前に一定時間待機し、他の移動体を送信元とする赤外線信号が受信されない場合にのみ、超音波信号を送信する仕組みが開示されている。 Currently, a system for measuring the propagation times of ultrasonic signals and radio wave signals (or infrared signals) and detecting the distance between the transmitting terminal and the receiving terminal based on the time difference has been proposed. This system pays attention to the fact that the radio wave signal (or infrared signal) propagates at the speed of light while the ultrasonic signal propagates slower than the speed of light, and that the difference in arrival time between the two signals substantially matches the propagation time of the ultrasonic signal. Consider the distance between terminals. By the way, when the system is operated, there may be a case where there are a plurality of transmitting terminals that transmit ultrasonic signals simultaneously in the space. In such a case, a technique for identifying each transmitting terminal is required for distance measurement. For example, in Patent Document 1, a mobile body (corresponding to a “transmission terminal”) waits for a certain period of time before transmitting an ultrasonic signal, and only when an infrared signal originating from another mobile body is not received. A mechanism for transmitting an ultrasonic signal is disclosed.
特開２０１１－１１３１４３号公報JP 2011-113143 A
　ところが、特許文献１に記載の技術には、次のような課題が生じることを発明者は発見した。 However, the inventors have found that the technique described in Patent Document 1 has the following problems.
(1)超音波信号の伝搬速度は遅いため、前述のシステムでは、衝突を避けるための待機時間が長くなってしまう。これは、測定の更新頻度の低下をもたらす。また、待機時間中は、常に赤外線信号の受信を待ち受ける状態にする必要があり、結果的に消費電力も増大してしまう。 (1) Since the propagation speed of the ultrasonic signal is slow, in the above-described system, the standby time for avoiding a collision becomes long. This leads to a decrease in the frequency of measurement updates. In addition, during the standby time, it is necessary to always wait for reception of an infrared signal, resulting in an increase in power consumption.
(2)前述のシステムにおいて赤外線信号が正常に受信できない場合、超音波信号の伝搬時間も測定できなくなるため、距離を測定できない。 (2) If the infrared signal cannot be received normally in the above-mentioned system, the propagation time of the ultrasonic signal cannot be measured, so the distance cannot be measured.
　そこで、本出願では、複数の送信端末と複数の受信端末が同時に運用される場合でも、効率良く送信端末と受信端末の間の距離を検知できる距離検知システムを提供する。 Therefore, the present application provides a distance detection system that can efficiently detect the distance between a transmission terminal and a reception terminal even when a plurality of transmission terminals and a plurality of reception terminals are operated simultaneously.
　上記課題を解決するために、例えば請求の範囲に記載の構成を採用する。本明細書は上記課題を解決する手段を複数含んでいるが、その一例を挙げるならば、以下の処理部を有する送信端末と受信端末で構成される距離検知システムである。 In order to solve the above problems, for example, the configuration described in the claims is adopted. The present specification includes a plurality of means for solving the above-described problems. To give an example, the distance detection system includes a transmission terminal and a reception terminal having the following processing units.
・送信端末が、(1)第一の媒体を通じて距離測定のための測距信号を送信する送信部と、(2)第一の媒体の伝送速度よりも伝送速度が速い第二の媒体を通じて制御信号を送受信する送受信部と、(3)前記測距信号の送信に先立つ所定の期間Ｔｃ中に、他の送信端末から送信された制御信号が受信されない場合に、前記測距信号の送信を許容すると共に前記測距信号の送信から計測期間Ｔｐの間、一定間隔Ｔｉ（＜Ｔｃ）毎に前記制御信号を送信させる送信制御部とを有する送信端末とを有する。 -The transmission terminal controls (1) a transmission unit that transmits a distance measurement signal through the first medium, and (2) a second medium whose transmission speed is higher than the transmission speed of the first medium. A transmission / reception unit that transmits and receives signals; and (3) transmission of the ranging signal is permitted when a control signal transmitted from another transmitting terminal is not received during a predetermined period Tc prior to transmission of the ranging signal. And a transmission terminal having a transmission control unit that transmits the control signal at regular intervals Ti (<Tc) during the measurement period Tp from the transmission of the distance measurement signal.
・受信端末が、(1)第一の媒体を通じて測距信号を受信する受信部と、(2)第二の媒体を通じて制御信号を送受信する送受信部と、(3)測距信号の受信時刻と制御信号の受信時刻との差に基づいて測距信号の伝搬時間を算出し、自端末と送信端末との距離を検知するタイミング検出部とを有する受信端末とを有する。 A receiving terminal (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) a reception time of the ranging signal; A receiving terminal having a timing detection unit that calculates a propagation time of the ranging signal based on a difference from the reception time of the control signal and detects a distance between the own terminal and the transmitting terminal;
　他の一例を挙げるならば、以下の処理部を有する送信端末と受信端末で構成される距離検知システムである。 If another example is given, it is a distance detection system composed of a transmission terminal and a reception terminal having the following processing units.
・送信端末が、(1)第一の媒体を通じて距離測定のための測距信号を送信する送信部であって、所定の拡散系列でスペクトラム拡散された測距信号を送信する送信部と、(2)第一の媒体の伝送速度よりも伝送速度が速い第二の媒体を通じて制御信号を送受信する送受信部であって、拡散系列情報を含む制御信号を送信する送受信部と、(3)前記測距信号の送信に先立つ所定の期間Ｔｃ中に、他の送信端末から送信された制御信号が受信されない場合に、前記測距信号の送信を許容する送信制御部とを有する。 A transmission terminal (1) a transmission unit that transmits a distance measurement signal for distance measurement through a first medium, and a transmission unit that transmits a ranging signal spectrum-spread by a predetermined spreading sequence; 2) a transmission / reception unit that transmits / receives a control signal through a second medium having a transmission rate higher than the transmission rate of the first medium, the transmission / reception unit transmitting a control signal including spreading sequence information; and (3) the measurement A transmission control unit that allows transmission of the distance measurement signal when a control signal transmitted from another transmission terminal is not received during a predetermined period Tc prior to transmission of the distance signal.
・受信端末が、(1)第一の媒体を通じて測距信号を受信する受信部と、(2)第二の媒体を通じて制御信号を送受信する送受信部と、(3)測距信号を制御信号に含まれる拡散系列情報を用いて逆拡散処理すると共に、測距信号の受信時刻と制御信号の受信時刻との差に基づいて測距信号の伝搬時間を算出し、自端末と送信端末との距離を検知するタイミング検出部とを有する。 The receiving terminal is (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) the ranging signal is used as a control signal. The despreading process is performed using the included spreading sequence information, and the propagation time of the ranging signal is calculated based on the difference between the reception time of the ranging signal and the reception time of the control signal, and the distance between the own terminal and the transmitting terminal And a timing detection unit for detecting.
　本発明によれば、複数の送信端末と複数の受信端末が同時に運用される場合でも、効率良く送信端末と受信端末の間の距離を検知することができる。前述した以外の課題、構成及び効果は、以下の実施の形態の説明により明らかにされる。 According to the present invention, even when a plurality of transmitting terminals and a plurality of receiving terminals are operated simultaneously, the distance between the transmitting terminal and the receiving terminal can be detected efficiently. Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.
実施例１における距離検知システムの概略構成を説明する図。1 is a diagram illustrating a schematic configuration of a distance detection system in Embodiment 1. FIG. 図１に示す距離検知システムを使用した位置検知システムの概略構成を説明する図。The figure explaining schematic structure of the position detection system which uses the distance detection system shown in FIG. 実施例１に適用可能な媒体の例を示す図表。FIG. 3 is a chart showing an example of a medium applicable to the first embodiment. 実施例１における送信端末の構成例を示す図。FIG. 3 is a diagram illustrating a configuration example of a transmission terminal according to the first embodiment. 測距信号送信時における送信端末の動作例を示すフローチャート。The flowchart which shows the operation example of the transmission terminal at the time of ranging signal transmission. 実施例１における受信端末の構成例を示す図。FIG. 3 is a diagram illustrating a configuration example of a receiving terminal according to the first embodiment. 実施例１における受信端末のタイミング検出部の構成例を示す図。3 is a diagram illustrating a configuration example of a timing detection unit of a receiving terminal in Embodiment 1. FIG. 実施例１における受信端末の制御信号受信時の動作例を示すフローチャート。3 is a flowchart illustrating an operation example of the receiving terminal when receiving a control signal in the first embodiment. 実施例１における測距シーケンス例を示す図。FIG. 3 is a diagram illustrating an example of a distance measurement sequence according to the first embodiment. 実施例１の制御信号に含まれる情報例を示す図表。FIG. 3 is a chart illustrating an example of information included in a control signal according to the first embodiment. FIG. 図１に示す距離検知システムを使用した位置検知システムの他の概略構成を説明する図。The figure explaining the other schematic structure of the position detection system using the distance detection system shown in FIG. 実施例２における送信端末の動作例を示すフローチャート。10 is a flowchart illustrating an operation example of a transmission terminal according to the second embodiment. 実施例２における受信端末の動作例を示すフローチャート。9 is a flowchart illustrating an operation example of a receiving terminal according to the second embodiment. 実施例２における測距シーケンス例を示す図。FIG. 10 is a diagram illustrating an example of a distance measurement sequence according to the second embodiment. 実施例２のＡＣＫ信号に含まれる情報例を示す図表。FIG. 6 is a chart showing an example of information included in an ACK signal of Embodiment 2. FIG. 測位結果及び相対速度結果に基づいた測定期間の削減効果を説明する図。The figure explaining the reduction effect of the measurement period based on a positioning result and a relative velocity result. 実施例３の制御信号に含まれる情報例を示す図。FIG. 10 is a diagram illustrating an example of information included in a control signal according to the third embodiment. 実施例３における送信端末の制御信号検出時の必要待機時間計算手順を示すフローチャート。9 is a flowchart illustrating a necessary standby time calculation procedure when a control signal of a transmitting terminal is detected in the third embodiment. 実施例３における測距シーケンス例を示す図。FIG. 10 is a diagram illustrating an example of a distance measurement sequence according to the third embodiment. 実施例４における送信端末の超音波送信部の構成例を示す図。FIG. 10 is a diagram illustrating a configuration example of an ultrasonic transmission unit of a transmission terminal according to a fourth embodiment. 実施例４における受信端末の構成例を示す図。FIG. 10 is a diagram illustrating a configuration example of a receiving terminal according to a fourth embodiment. 実施例４における受信端末のタイミング検出部の構成例を示す図。FIG. 10 is a diagram illustrating a configuration example of a timing detection unit of a receiving terminal according to a fourth embodiment. 実施例４における測距シーケンス例（その１）を示す図。FIG. 10 is a diagram illustrating a distance measurement sequence example (part 1) according to the fourth embodiment. 実施例４における測距シーケンス例（その２）を示す図。FIG. 12 is a diagram illustrating a distance measurement sequence example (part 2) according to the fourth embodiment. 実施例４における制御信号に含まれる情報例を示す図表。FIG. 10 is a chart showing an example of information included in a control signal in Embodiment 4. FIG. 実施例４における逆拡散処理により復号された周波数推定波形の例を示す図。FIG. 10 is a diagram illustrating an example of a frequency estimation waveform decoded by despreading processing according to the fourth embodiment. 実施例５における受信端末の構成例を示す図。FIG. 10 is a diagram illustrating a configuration example of a receiving terminal according to a fifth embodiment. 実施例５における受信端末のタイミング・位相差検出部の構成例を示す図。FIG. 10 is a diagram illustrating a configuration example of a timing / phase difference detection unit of a receiving terminal according to a fifth embodiment.
　以下、図面に基づいて、本発明の実施の形態を説明する。なお、本発明の実施の態様は、後述する形態例に限定されるものではなく、その技術思想の範囲において、種々の変形が可能である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment of the present invention is not limited to the embodiments described later, and various modifications are possible within the scope of the technical idea.
　［実施例１］
　（１）システム構成
　（１－１）距離検知システム
　図１に、本実施例に係る距離検知システムの概略構成を示す。図１に示す距離検知システムは、受信端末１と、送信端末２Ａ及び２Ｂとで構成される。受信端末１は、送信端末２Ａ及び２Ｂのそれぞれから送信された信号の伝搬時間を測定し、受信端末１と送信端末２Ａの距離ｄ１と受信端末１と送信端末２Ｂの距離ｄ２を測定する。図１では、送信端末が２台の場合を表しているが、送信端末は１台でも良いし、３台以上でもよい。 [Example 1]
(1) System Configuration (1-1) Distance Detection System FIG. 1 shows a schematic configuration of the distance detection system according to the present embodiment. The distance detection system shown in FIG. 1 includes a receiving terminal 1 and transmitting terminals 2A and 2B. The receiving terminal 1 measures the propagation times of signals transmitted from the transmitting terminals 2A and 2B, and measures the distance d1 between the receiving terminal 1 and the transmitting terminal 2A and the distance d2 between the receiving terminal 1 and the transmitting terminal 2B. Although FIG. 1 shows the case where there are two transmission terminals, the number of transmission terminals may be one or three or more.
　（１－２）位置検知システム１
　図２に、本実施例に係る位置検知システムの概略構成例を示す。図２に示す位置検知システムは、受信端末１Ａ及び１Ｂと、送信端末２Ａ及び２Ｂと、測位装置３とで構成される。この位置検知システムは、図１に示す距離検知システムを利用して測定された一組の距離ｄ１１及びｄ１２、又は、ｄ２１及びｄ２２に基づいて、受信端末１Ａ及び１Ｂにより規定される座標系上での送信端末２Ａ及び２Ｂの相対的な位置を検知する。図２の場合、座標系は、受信端末１Ａ及び１Ｂを結ぶ軸（ｙ軸）と、受信端末１Ａ及び１Ｂの中点位置を通り、ｙ軸に直交する軸（ｘ軸）とで与えられる。もっとも、座標系の定め方は、図２の例に限らない。 (1-2) Position detection system 1
FIG. 2 shows a schematic configuration example of the position detection system according to the present embodiment. The position detection system shown in FIG. 2 includes receiving terminals 1A and 1B, transmitting terminals 2A and 2B, and a positioning device 3. This position detection system is based on a set of distances d11 and d12 or d21 and d22 measured using the distance detection system shown in FIG. 1 on a coordinate system defined by the receiving terminals 1A and 1B. The relative positions of the transmitting terminals 2A and 2B are detected. In the case of FIG. 2, the coordinate system is given by an axis (y axis) connecting the receiving terminals 1A and 1B and an axis (x axis) passing through the midpoint position of the receiving terminals 1A and 1B and orthogonal to the y axis. However, the method of determining the coordinate system is not limited to the example of FIG.
　図２の場合、２台の受信端末１Ａ及び１Ｂは、ｙ軸上の座標Ｓ１及びＳ２に設置されている。受信端末１Ａは、送信端末２Ａとの距離ｄ１１と送信端末２Ｂとの距離ｄ２１を測定する。受信端末１Ｂは、送信端末２Ａとの距離ｄ１２と送信端末２Ｂとの距離ｄ２２を測定する。これら４つの距離は、有線路又は無線路を通じ、受信端末１Ａ及び１Ｂから測位装置３に送信される。測位装置３は、距離ｄ１１及びｄ１２に基づいて送信端末２Ａの座標Ｐ１（ｘ１、ｙ１）を算出し、距離ｄ２１及びｄ２２に基づいて送信端末２Ｂの座標Ｐ２（ｘ２、ｙ２）を算出する。 In the case of FIG. 2, the two receiving terminals 1A and 1B are installed at coordinates S1 and S2 on the y-axis. The receiving terminal 1A measures the distance d11 between the transmitting terminal 2A and the distance d21 between the transmitting terminal 2B. The receiving terminal 1B measures the distance d12 to the transmitting terminal 2A and the distance d22 to the transmitting terminal 2B. These four distances are transmitted from the receiving terminals 1A and 1B to the positioning device 3 through a wired path or a wireless path. The positioning device 3 calculates the coordinates P1 (x1, y1) of the transmission terminal 2A based on the distances d11 and d12, and calculates the coordinates P2 (x2, y2) of the transmission terminals 2B based on the distances d21 and d22.
　（１－３）通信に使用する媒体
　図１及び図２に示すシステムにおける送信端末２Ａ及び２Ｂは、距離測定のための測距信号の送信と、同期や情報のやり取りを行う制御信号の送信に異なる媒体を使用する。図３に、媒体の組み合わせ候補を示す。なお、測距信号用の媒体には、制御信号用の媒体よりも伝搬速度が遅いものが用いられる。以下の説明では、測距信号用の媒体に超音波を使用し、制御信号用の媒体には無線（電波）を使用する例について説明する。勿論、本明細書で説明する発明の主旨は、媒体の種類に限定されない。 (1-3) Medium used for communication The transmission terminals 2A and 2B in the system shown in FIGS. 1 and 2 are used for transmission of distance measurement signals for distance measurement and transmission of control signals for synchronization and information exchange. Use different media. FIG. 3 shows medium combination candidates. As the distance measurement signal medium, a medium having a slower propagation speed than the control signal medium is used. In the following description, an example will be described in which ultrasonic waves are used as the distance measurement signal medium and radio waves (radio waves) are used as the control signal medium. Of course, the gist of the invention described in this specification is not limited to the type of medium.
　（２）送信端末
　図４に、送信端末の機能構成例を示す。送信端末は、制御部１１、超音波送信制御部１２、無線送信制御部１３、制御信号検出部１４、超音波送信部１５、無線送受信部１６、超音波変換素子１７、無線変換素子１８を含む。必要に応じ、送信端末は、各種センサ１９も含む。このうち、超音波送信制御部１２、超音波送信部１５、超音波変換素子１７は測距信号の送信用である。また、無線送信制御部１３、制御信号検出部１４、無線送受信部１６、無線変換素子１８は制御信号の送受信用である。 (2) Transmission terminal FIG. 4 shows an example of the functional configuration of the transmission terminal. The transmission terminal includes a control unit 11, an ultrasonic transmission control unit 12, a wireless transmission control unit 13, a control signal detection unit 14, an ultrasonic transmission unit 15, a wireless transmission / reception unit 16, an ultrasonic conversion element 17, and a wireless conversion element 18. . The transmission terminal also includes various sensors 19 as necessary. Among these, the ultrasonic transmission control unit 12, the ultrasonic transmission unit 15, and the ultrasonic transducer 17 are used for transmitting a distance measurement signal. The wireless transmission control unit 13, the control signal detection unit 14, the wireless transmission / reception unit 16, and the wireless conversion element 18 are used for transmission / reception of control signals.
　超音波変換素子１７は、電気信号を超音波信号に変換する素子（例えば超音波センサ）である。無線変換素子１８は、電気信号と無線信号を相互に変換する素子（例えばアンテナ）である。勿論、超音波と無線（電波）以外の媒体を使用する場合には、使用する媒体に適した変換素子が用いられる。 The ultrasonic transducer 17 is an element (for example, an ultrasonic sensor) that converts an electrical signal into an ultrasonic signal. The wireless conversion element 18 is an element (for example, an antenna) that mutually converts an electrical signal and a wireless signal. Of course, when a medium other than ultrasonic waves and radio waves (radio waves) is used, a conversion element suitable for the medium to be used is used.
　超音波送信部１５は、超音波送信制御部１２の制御により変調信号を生成する。超音波変換素子１７は、この変調信号を変換した超音波信号を空間に放射する。無線送受信部１６は、無線信号の送信機能部と受信機能部を有している。無線送受信部１６の受信機能部は、無線変換素子１８において電気信号に変換された受信信号を処理し、受信データとして制御信号検出部１４に与える。制御信号検出部１４は、受信データの入力を検出して制御部１１に与える。無線送信制御部１３は、送信データを生成して無線送受信部１６に与えるなどの通信制御を行う。無線送受信部１６の送信機能部は、送信データを無線信号の送信に適した送信信号に変調する。無線変換素子１８は、送信データに対応する無線信号を空間に放射する。制御部１１は、送信端末全体のタイミング制御を行う。 The ultrasonic transmission unit 15 generates a modulation signal under the control of the ultrasonic transmission control unit 12. The ultrasonic transducer 17 radiates an ultrasonic signal obtained by converting the modulation signal into space. The wireless transmission / reception unit 16 includes a wireless signal transmission function unit and a reception function unit. The reception function unit of the wireless transmission / reception unit 16 processes the reception signal converted into an electric signal by the wireless conversion element 18 and supplies the received signal to the control signal detection unit 14 as reception data. The control signal detection unit 14 detects the input of received data and gives it to the control unit 11. The wireless transmission control unit 13 performs communication control such as generating transmission data and giving it to the wireless transmission / reception unit 16. The transmission function unit of the radio transmission / reception unit 16 modulates transmission data into a transmission signal suitable for transmission of a radio signal. The wireless conversion element 18 radiates a wireless signal corresponding to the transmission data into space. The control unit 11 performs timing control for the entire transmission terminal.
　図５に、測距信号送信時の送信端末の動作例を示す。図５は、周期的（周期Ｔｒ秒）に測距信号を送信する場合の動作を示している。前回の送信信号の送信からＴｒ秒経過した後（Ｓ１）、制御部１１は、他の送信端末からの制御信号が無線送受信部１６において受信されているか否かを一定期間（Ｔｃ秒）確認する（Ｓ２、Ｓ３）。もし、同時間内に制御信号が受信された場合、制御部１１は、待機すべき時間を計算し、計算された時間だけ待機する状態になる（Ｓ７）。待機時間が経過すると、制御部１１はＳ２に戻り、再び他の送信端末からの制御信号の受信を待ち受ける状態に戻る。 FIG. 5 shows an example of the operation of the transmitting terminal when transmitting a ranging signal. FIG. 5 shows an operation in the case of transmitting a distance measurement signal periodically (cycle Tr seconds). After Tr seconds have passed since the transmission of the previous transmission signal (S1), the control unit 11 checks whether a control signal from another transmission terminal is received by the wireless transmission / reception unit 16 for a certain period (Tc seconds). (S2, S3). If the control signal is received within the same time, the control unit 11 calculates the time to wait and enters a state of waiting for the calculated time (S7). When the standby time has elapsed, the control unit 11 returns to S2, and again returns to a state of waiting for reception of a control signal from another transmission terminal.
　ここで、待機時間は、受信した制御信号の送信元の送信端末が送信する測距信号と、自端末がこれから送信する測距信号とが衝突する可能性のある時間である。好適な実施例では、待機時間は、受信した制御信号に含まれる残り計測期間長に基づいて計算される。なお、この待機時間に、送信端末に固有の値やランダム性を持たせれば、３つ以上の送信端末が存在する場合でも、各送信端末において実行される送信可否の判定期間がずれるため、測距信号の衝突を効果的に回避できる。 Here, the standby time is a time during which the ranging signal transmitted from the transmission terminal that is the transmission source of the received control signal may collide with the ranging signal transmitted from the terminal itself. In a preferred embodiment, the waiting time is calculated based on the remaining measurement period length included in the received control signal. Note that if this waiting time is given a value or randomness that is unique to the transmitting terminal, even if there are three or more transmitting terminals, the determination period of whether transmission is possible or not will be shifted in each transmitting terminal. Distance signal collision can be effectively avoided.
　一方、Ｓ３において制御信号が検出されない場合、制御部１１は、測距信号を超音波送信部１５、超音波変換素子１７を通じて送信する（Ｓ４）。この送信と同時に、制御部１１は、制御信号も無線送受信部１６、無線変換素子１８を通じて送信する（Ｓ５）。以降、制御部１１は、測距信号と同時に送信した制御信号の送信からＴｐ秒が経過するまでの間、周期的に（Ｔｉ秒毎に）制御信号を間欠的に送信する（Ｓ５、Ｓ６、Ｓ８）。制御部１１は、前記Ｔｐ秒の経過後、制御信号の送信を停止し、次の送信時間まで待機する（Ｓ１）。 On the other hand, when the control signal is not detected in S3, the control unit 11 transmits the distance measurement signal through the ultrasonic transmission unit 15 and the ultrasonic transducer 17 (S4). Simultaneously with this transmission, the control unit 11 also transmits a control signal through the wireless transmission / reception unit 16 and the wireless conversion element 18 (S5). Thereafter, the control unit 11 intermittently transmits the control signal periodically (every Ti seconds) until Tp seconds elapse after transmission of the control signal transmitted simultaneously with the ranging signal (S5, S6, S8). After the lapse of Tp seconds, the control unit 11 stops transmitting the control signal and waits until the next transmission time (S1).
　ただし、他の送信端末からの制御信号の受信抜けを防ぐため、Ｔｉ＜Ｔｃの関係を満たす必要がある。Ｔｉを短くすると（すなわち、制御信号の間欠送信時間を短くすると）、制御信号の待ち受け時間であるＴｃも短くできる。Ｔｃの短縮は、測定効率の向上と低消費電力化を可能とする。ただし、Ｔｃを短縮すると、トレードオフの関係として、空間占有確率が大きくなるため、同時端末稼働数の低下をもたらす。 However, it is necessary to satisfy the relationship of Ti <Tc in order to prevent missing control signals from other transmitting terminals. If Ti is shortened (that is, the intermittent transmission time of the control signal is shortened), the control signal waiting time Tc can also be shortened. The shortening of Tc makes it possible to improve measurement efficiency and reduce power consumption. However, if Tc is shortened, the space occupancy probability increases as a trade-off relationship, resulting in a decrease in the number of simultaneous terminal operations.
　以上のように、本実施例の送信端末では、測距信号の衝突回避のために制御信号を受信する期間はＴｃ秒だけであるので、他の送信端末から送信された測距信号との間で衝突が発生する可能性がある全期間の間、制御信号を待ち受ける場合に比して消費電力を少なくできる。本実施例の仕組みの採用により、それぞれが独立に動作している送信端末から送信される測距信号の衝突の可能性を格段に低下でき、端末間の距離を高い頻度で測定できる。このことは、測定距離の精度又は信頼性の向上に寄与する。 As described above, in the transmission terminal of this embodiment, the control signal is received for only Tc seconds for avoiding the collision of the distance measurement signal, so that the distance between the distance measurement signals transmitted from other transmission terminals is Thus, the power consumption can be reduced as compared with the case of waiting for the control signal during the entire period during which the collision may occur. By adopting the mechanism of this embodiment, the possibility of collision of ranging signals transmitted from the transmitting terminals operating independently can be remarkably reduced, and the distance between terminals can be measured with high frequency. This contributes to an improvement in the accuracy or reliability of the measurement distance.
　（３）受信端末
　図６に、受信端末の機能構成例を示す。受信端末は、超音波変換素子１７、無線変換素子１８、超音波受信部２１、無線送受信部２２、タイミング検出部２３、制御部２４、データ処理部２５を含む。このうち、超音波変換素子１７、超音波受信部２１、タイミング検出部２３は測距信号の受信用である。また、無線変換素子１８、無線送受信部２２は制御信号の送受信用である。 (3) Receiving Terminal FIG. 6 shows a functional configuration example of the receiving terminal. The receiving terminal includes an ultrasonic transducer 17, a radio transducer 18, an ultrasonic receiver 21, a wireless transmitter / receiver 22, a timing detector 23, a controller 24, and a data processor 25. Among these, the ultrasonic transducer 17, the ultrasonic receiver 21, and the timing detector 23 are used for receiving ranging signals. The wireless conversion element 18 and the wireless transmission / reception unit 22 are used for transmission / reception of control signals.
　無線送受信部２２は、無線変換素子１８において無線信号から変換された電気信号を復調し、制御部２４に制御信号等のデータを通知する。超音波受信部２１は、超音波変換素子１７において超音波信号から変換された電気信号の増幅処理及びフィルタ処理（アナログ処理）を実行し、タイミング検出部２３に伝送する。制御部２４は、制御信号を受信した際に、制御信号に含まれる測距信号の残り計測期間長及び測距信号の送信時刻情報をタイミング検出部２３に提供する。 The wireless transmission / reception unit 22 demodulates the electrical signal converted from the wireless signal by the wireless conversion element 18 and notifies the control unit 24 of data such as a control signal. The ultrasonic receiving unit 21 performs amplification processing and filter processing (analog processing) on the electrical signal converted from the ultrasonic signal in the ultrasonic transducer 17 and transmits the amplified signal to the timing detection unit 23. When receiving the control signal, the control unit 24 provides the timing detection unit 23 with the remaining measurement period length of the ranging signal and the transmission time information of the ranging signal included in the control signal.
　タイミング検出部２３は、測距信号の伝搬時間を検出する。また、タイミング検出部２３は、当該検出に際し、受信した測距信号の周波数シフトも検出する。図７に、タイミング検出部２３の構成例を示す。サンプリング部３１は、制御部２４から提供される計測期間Ｔｐの間だけサンプリングが行われる。周波数推定部３２は、サンプリング部３１でサンプリングされたデータを入力し、キャリア周波数の周波数シフト量を推定する。 The timing detector 23 detects the propagation time of the distance measurement signal. In addition, the timing detection unit 23 also detects a frequency shift of the received ranging signal at the time of the detection. FIG. 7 shows a configuration example of the timing detection unit 23. The sampling unit 31 performs sampling only during the measurement period Tp provided from the control unit 24. The frequency estimation unit 32 receives the data sampled by the sampling unit 31 and estimates the frequency shift amount of the carrier frequency.
　時間差検出部３３は、測距信号と制御信号の受信時刻差、又は、当該受信時刻差と測距信号の送信時刻情報とに基づいて、測距信号の伝搬時間を検出する。例えば１番目の制御信号（測距信号と同時に送信された制御信号）が受信された場合、測距信号と制御信号の受信時刻差は、そのまま測距信号の伝搬時間に相当する。一方、１番目の制御信号が受信できずに２番目の制御信号が受信された場合、制御信号に含まれる情報から測距信号の送信時刻を計算し、受信時刻差（２番目の制御信号の受信時刻と測距信号の受信時刻の差）と測距信号の送信時刻とに基づいて測距信号の伝搬時間を計算する。具体的には、測距信号の送信時刻と２番目の制御信号の受信時刻との時間差と、前記受信時刻差（２番目の制御信号の受信時刻と測距信号の受信時刻の差）との和を計算する。 The time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal. For example, when the first control signal (control signal transmitted at the same time as the ranging signal) is received, the reception time difference between the ranging signal and the control signal corresponds to the propagation time of the ranging signal as it is. On the other hand, when the second control signal is received without receiving the first control signal, the transmission time of the distance measurement signal is calculated from the information included in the control signal, and the reception time difference (the second control signal The propagation time of the distance measurement signal is calculated based on the difference between the reception time and the reception time of the distance measurement signal) and the transmission time of the distance measurement signal. Specifically, the time difference between the transmission time of the distance measurement signal and the reception time of the second control signal and the reception time difference (the difference between the reception time of the second control signal and the reception time of the distance measurement signal) Calculate the sum.
　なお、測距信号の送信時刻は、例えば制御信号に付加されている測距信号の送信時刻情報から得ることができる。また、制御信号の送信周期が予め分かっている場合には、制御信号に付加されているシーケンス番号から１番目の制御信号の送信時刻を計算することができる。制御信号が同じ測距信号に対して送信された１番目の信号であるか２番目の信号であるかは、制御信号に含まれる制御信号のシーケンス番号より分かる。受信された制御信号が３番目以降の制御信号の場合にも、前述の手法と同様の手法により測距信号の伝搬時間を検出できる。 The transmission time of the distance measurement signal can be obtained from the transmission time information of the distance measurement signal added to the control signal, for example. When the transmission cycle of the control signal is known in advance, the transmission time of the first control signal can be calculated from the sequence number added to the control signal. Whether the control signal is the first signal or the second signal transmitted with respect to the same distance measurement signal is known from the sequence number of the control signal included in the control signal. Even when the received control signal is the third and subsequent control signals, the propagation time of the ranging signal can be detected by the same method as described above.
　データ処理部２５は、タイミング検出部２３で得られた伝搬時間を測距信号の伝搬距離に変換する。また、データ処理部２５は、必要に応じ、周波数シフト量からドップラーシフトの原理より相対速度を計算する。また、データ処理部２５は、必要に応じ、それらのデータを他装置（送信端末及び受信端末を含む）に、送信端末のＩＤ情報と共に伝送する。 The data processing unit 25 converts the propagation time obtained by the timing detection unit 23 into the propagation distance of the distance measurement signal. Further, the data processing unit 25 calculates the relative speed from the frequency shift amount according to the principle of Doppler shift as necessary. In addition, the data processing unit 25 transmits the data to other devices (including the transmission terminal and the reception terminal) together with ID information of the transmission terminal as necessary.
　図８に、制御信号受信時の受信端末の動作例を示す。制御信号を受信した制御部２４は、当該信号が新しい測距信号用の制御信号か否かを判断する（Ｓ１１）。受信した制御信号が、既に受信された制御信号と同じ測距信号用の信号である場合、既に測距信号の受信処理が開始されているので、制御部２４は何もしない。なお、制御信号が対応する測距信号は、例えば制御信号に含まれる測距信号のシーケンス番号により確認できる。 FIG. 8 shows an operation example of the receiving terminal when receiving the control signal. The control unit 24 that has received the control signal determines whether or not the signal is a control signal for a new ranging signal (S11). If the received control signal is a signal for a distance measurement signal that is the same as the control signal that has already been received, since the reception process of the distance measurement signal has already been started, the control unit 24 does nothing. The ranging signal corresponding to the control signal can be confirmed by, for example, the sequence number of the ranging signal included in the control signal.
　一方、受信した制御信号が、新しい測距信号に対応する制御信号である場合、制御部２４は、タイミング情報をタイミング検出部２３に与え、一定時間、超音波信号をサンプリングする（Ｓ１２）。サンプリングする時間は、制御信号が受信された時刻から、超音波の測距信号が到達する可能性のある時刻までである。超音波の測距信号が到達する可能性のある時刻は、好ましくは制御信号内に計測期間情報に含まれている。この後、タイミング検出部２３は、サンプリングされたデータに基づいて測距信号の伝搬時間を測定し（Ｓ１３）、その値から送信端末までの距離を計算する（Ｓ１４）。 On the other hand, when the received control signal is a control signal corresponding to a new ranging signal, the control unit 24 gives timing information to the timing detection unit 23, and samples the ultrasonic signal for a certain time (S12). The sampling time is from the time when the control signal is received to the time when the ultrasonic ranging signal may arrive. The time at which the ultrasonic ranging signal may reach is preferably included in the measurement period information in the control signal. Thereafter, the timing detection unit 23 measures the propagation time of the distance measurement signal based on the sampled data (S13), and calculates the distance to the transmission terminal from the value (S14).
　当該動作機能の搭載により、受信端末は、仮に１番目の制御信号の受信に失敗した場合でも、２番目の制御信号を受信できれば、測距信号の送信時刻を知ることができ、即時に測距信号の伝搬時間を測定することができる。すなわち、本実施例の手法では、複数回の制御信号のうちいずれか１つを受信できれば、測距信号の伝搬時間を測定することができる。 By installing this operation function, even if the receiving terminal fails to receive the first control signal, if the receiving terminal can receive the second control signal, the receiving terminal can know the transmission time of the distance measuring signal and can immediately measure the distance. The signal propagation time can be measured. That is, in the method of the present embodiment, if any one of a plurality of control signals can be received, the propagation time of the ranging signal can be measured.
　（４）測距シーケンス
　図９に、前述の通信機能を備える送信端末及び受信端末によって実現される測距シーケンスの例を示す。なお、図９は、図１に示す距離検知システムを前提とするものであり、送信端末２Ａが測距信号を送信している間に、送信端末２Ｂが測距信号を送信しようとしているところを表している。送信端末２Ｂは、前述の制御信号待受動作（Ｓ２、Ｓ３）中に、送信端末２Ａからの制御信号を受信したので、必要待機時間だけ待機し（Ｓ７）、送信端末２Ａの計測期間が終わった後に、自信の測距信号を送信している。受信端末１では、制御信号を受信した時刻から制御信号内で示された計測期間（Ｔｐ秒）の間のみ、測距信号の受信を行い、その伝搬時間を検出している。 (4) Ranging Sequence FIG. 9 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having the communication function described above. FIG. 9 is based on the distance detection system shown in FIG. 1 and shows that the transmission terminal 2B is about to transmit a distance measurement signal while the transmission terminal 2A is transmitting the distance measurement signal. Represents. Since the transmission terminal 2B receives the control signal from the transmission terminal 2A during the control signal standby operation (S2, S3) described above, the transmission terminal 2B waits for the necessary waiting time (S7), and the measurement period of the transmission terminal 2A ends. After that, send a confidence ranging signal. The receiving terminal 1 receives the ranging signal only during the measurement period (Tp seconds) indicated in the control signal from the time when the control signal is received, and detects its propagation time.
　（５）制御信号内に含まれる情報
　図１０に、送信端末から受信端末に送信される制御信号に含めて好適な情報の例を示す。図１０は、制御信号に、送信端末が持つ固有の識別番号（ＩＤ）、測距信号のシーケンス番号、制御信号のシーケンス番号、測距信号の送信時刻情報、残り計測期間長が含まれる場合の例である。勿論、制御信号には他の補正情報を追加することもできる。例えば、測距信号の送信に超音波を使用する場合、温度に伝搬速度が依存するため、送信端末に搭載したセンサによって測定された温度を制御信号に含めてもよい。この場合、受信端末は、受信した温度を距離計算時の補正値として利用する。その他、距離又は位置の算出時に使えるセンサ情報として、加速度データ、方位データ、角速度データなどを、制御信号に含めてもよい。なお、図１０に例示した全ての情報を制御信号に含める必要はなく、その一部だけを制御信号に含めてもよい。 (5) Information included in control signal FIG. 10 shows an example of suitable information included in the control signal transmitted from the transmitting terminal to the receiving terminal. FIG. 10 shows a case where the control signal includes a unique identification number (ID) of the transmission terminal, a ranging signal sequence number, a control signal sequence number, ranging signal transmission time information, and a remaining measurement period length. It is an example. Of course, other correction information can be added to the control signal. For example, when an ultrasonic wave is used for transmission of a distance measurement signal, since the propagation speed depends on the temperature, the temperature measured by a sensor mounted on the transmission terminal may be included in the control signal. In this case, the receiving terminal uses the received temperature as a correction value when calculating the distance. In addition, acceleration data, azimuth data, angular velocity data, and the like may be included in the control signal as sensor information that can be used when calculating the distance or position. Note that it is not necessary to include all the information illustrated in FIG. 10 in the control signal, and only a part of the information may be included in the control signal.
　（６）他の位置検知システム
　ここでは、前述した位置検知システム（図２）の変形例を説明する。前述の図２に示す位置検知システムにおいては、固定局である受信端末１Ａ及び１Ｂに対する送信端末の相対位置を、受信端末１Ａ及び１Ｂに接続された測位装置３で求める構成を説明した。図１１に示す位置検知システムは、送信端末が固定局である場合である。この場合、２つの送信端末１Ｃ及び１Ｄのそれぞれが、各自の相対位置情報を制御信号に含めて送信し、受信端末１Ｃ及び１Ｄのそれぞれが、各送信端末から受信した測距信号の伝搬時間（換算距離）を測定する。各受信端末は、送信端末１Ｃ及び１Ｄとの間の測定距離と送信端末の相対位置の情報に基づいて、送信端末１Ｃ及び１Ｄに対する受信端末の位置を計算する。 (6) Other position detection system Here, the modification of the position detection system (FIG. 2) mentioned above is demonstrated. In the position detection system illustrated in FIG. 2 described above, the configuration in which the relative position of the transmitting terminal with respect to the receiving terminals 1A and 1B, which are fixed stations, is obtained by the positioning device 3 connected to the receiving terminals 1A and 1B has been described. The position detection system shown in FIG. 11 is a case where the transmitting terminal is a fixed station. In this case, each of the two transmitting terminals 1C and 1D transmits their relative position information included in the control signal, and each of the receiving terminals 1C and 1D transmits the propagation time of the ranging signal received from each transmitting terminal ( Measure the conversion distance. Each receiving terminal calculates the position of the receiving terminal with respect to the transmitting terminals 1C and 1D based on the measurement distance between the transmitting terminals 1C and 1D and the information on the relative position of the transmitting terminal.
　（７）まとめ
　前述した距離検知システム（図１）及び位置検知システム（図２、図１１）は、複数の送信端末と複数の受信端末が同時に運用される空間でも使用可能である。また、実施例に係る距離検知システムは、前述したように、測距開始前の待機時間を短くでき、測定回数を増やすことができる。また、送信端末における制御信号の待ち受け期間Ｔｃの短縮により、当該待ち受けに要する消費電力を抑制することができる。さらに、本実施例に係る距離検知システムでは、複数の制御信号の送信により、１番目の制御信号の受信に失敗しても２番目以降の制御信号により距離検知が可能であり、測定頻度を高めることができる。この結果、測定された距離や位置の信頼性の高い距離検知システム及び位置検知システムを実現できる。 (7) Summary The distance detection system (FIG. 1) and position detection system (FIGS. 2 and 11) described above can be used in a space where a plurality of transmission terminals and a plurality of reception terminals are operated simultaneously. Further, as described above, the distance detection system according to the embodiment can shorten the standby time before the start of distance measurement, and can increase the number of measurements. Further, by shortening the control signal waiting period Tc in the transmitting terminal, it is possible to suppress power consumption required for the waiting. Furthermore, in the distance detection system according to the present embodiment, even if reception of the first control signal fails due to transmission of a plurality of control signals, distance detection is possible with the second and subsequent control signals, and the measurement frequency is increased. be able to. As a result, a distance detection system and a position detection system with high reliability of the measured distance and position can be realized.
　［実施例２］
　ここでは、受信端末の側から送信端末の側に時分割多重されたトリガ信号（例えばＡＣＫ信号）を赤外線信号により送信するシステムについて検討する。なお、前述の特許文献１に記載の技術を当該システムに応用する場合、互いに独立に動作する複数の受信端末から送信される複数のトリガ信号の衝突や受信端末から送信されるトリガ信号と送信端末から送信される超音波信号の衝突が発生してしまう。そこで、本実施例では、受信端末の側から送信端末の側に時分割多重されたＡＣＫ信号が送信される場合でも、ＡＣＫ信号同士やＡＣＫ信号と測距信号との衝突を回避する技術について説明する。 [Example 2]
Here, a system in which a trigger signal (for example, an ACK signal) time-division multiplexed from the receiving terminal side to the transmitting terminal side is transmitted by an infrared signal is considered. When the technique described in Patent Document 1 is applied to the system, a collision between a plurality of trigger signals transmitted from a plurality of receiving terminals operating independently from each other, a trigger signal transmitted from the receiving terminal, and a transmitting terminal The collision of the ultrasonic signal transmitted from will occur. Thus, in this embodiment, a technique for avoiding collision between ACK signals or between ACK signals and ranging signals even when ACK signals time-division multiplexed are transmitted from the receiving terminal side to the transmitting terminal side. To do.
　（１）システム構成
　本実施例で想定する距離検知システム及び位置検出システムは、いずれも実施例１で説明した距離検知システム（図１）及び位置検出システム（図２、図１１）と同様であり、当該システムを構成する送信端末と受信端末の構成も実施例１と同様である。ただし、受信端末によるＡＣＫ信号の送信には、無線（電波）が用いられる。 (1) System Configuration The distance detection system and the position detection system assumed in this embodiment are the same as the distance detection system (FIG. 1) and the position detection system (FIGS. 2 and 11) described in the first embodiment. The configurations of the transmission terminal and the reception terminal that constitute the system are the same as those in the first embodiment. However, radio (radio wave) is used for transmission of the ACK signal by the receiving terminal.
　（２）送信端末の動作
　図１２に、本実施例で使用する送信端末の動作例を示す。図１２には、図５との対応部分に同一符号を付して示している。図１２に示す動作と図５に示す動作の違いの１つは、Ｔｃ秒間の制御信号待ち受けステップ（Ｓ２）に続いて実行される判定処理において、他の送信端末からの制御信号に加え、受信端末からのＡＣＫ信号の検出動作も実行する点である（Ｓ２１）。他の違いは、制御信号の送信（Ｓ５）後に受信端末からのＡＣＫ信号を受信する点である（Ｓ２２）。その他の動作は、図５で示した動作例と同様である。 (2) Operation of Transmission Terminal FIG. 12 shows an operation example of the transmission terminal used in this embodiment. In FIG. 12, parts corresponding to those in FIG. One of the differences between the operation shown in FIG. 12 and the operation shown in FIG. 5 is that in the determination process executed following the control signal waiting step (S2) for Tc seconds, in addition to the control signals from other transmitting terminals, An operation for detecting an ACK signal from the terminal is also executed (S21). Another difference is that an ACK signal from the receiving terminal is received after transmission of the control signal (S5) (S22). Other operations are similar to the operation example shown in FIG.
　（３）受信端末の動作
　図１３に、本実施例で使用する受信端末の動作例を示す。図１３には、図８との対応部分に同一符号を付して示している。図１３に示す動作と図８に示す動作の違いの１つは、制御信号の受信後に、ＡＣＫ信号を送信するステップ（Ｓ３1）を、受信処理（Ｓ１１以降）と並行に実行する点である。なお、ＡＣＫ信号の送信は、受信端末に固有の待機時間、又は、ランダム時間だけ待機してから行う。これにより同じ空間内に複数の受信端末が存在した場合でも、複数の受信端末から送信されたＡＣＫ信号が衝突するのを防ぐことができる。他の違いは、測距信号の受信による距離計算の結果を反映したＡＣＫ信号を、該当する送信端末に送信するステップ（Ｓ３２）が追加されている点である。 (3) Operation of Receiving Terminal FIG. 13 shows an operation example of the receiving terminal used in this embodiment. In FIG. 13, parts corresponding to those in FIG. 8 are given the same reference numerals. One of the differences between the operation shown in FIG. 13 and the operation shown in FIG. 8 is that, after receiving the control signal, the step of transmitting the ACK signal (S31) is executed in parallel with the reception process (S11 and subsequent steps). Note that the transmission of the ACK signal is performed after waiting for a waiting time unique to the receiving terminal or a random time. Thereby, even when there are a plurality of receiving terminals in the same space, collision of ACK signals transmitted from the plurality of receiving terminals can be prevented. Another difference is that a step (S32) of transmitting an ACK signal reflecting the result of distance calculation by receiving the distance measurement signal to the corresponding transmitting terminal is added.
　（４）測距シーケンス
　図１４に、本実施例に係る通信機能を備える送信端末及び受信端末によって実現される測距シーケンスの例を示す。なお、図１４は、図２に示す位置検出システムのように、２つの送信端末２Ａ、２Ｂが２つの受信端末１Ａ、１Ｂに対して測距信号をそれぞれ送信する場合を想定するものであり、送信端末２Ａの距離の計測期間中に、送信端末２Ａからの制御信号を受信した２つの受信端末１Ａ及び１ＢのそれぞれがＡＣＫ信号を返信しようとしているところを表している。前述したように、この実施例では、ＡＣＫ信号の衝突を防ぐため、端末固有の待機時間又はランダムの待機時間が、受信端末１Ａ及び１Ｂのそれぞれに設けられている。 (4) Ranging Sequence FIG. 14 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having a communication function according to the present embodiment. Note that FIG. 14 assumes a case where the two transmission terminals 2A and 2B transmit distance measurement signals to the two reception terminals 1A and 1B, respectively, as in the position detection system shown in FIG. This shows that each of the two receiving terminals 1A and 1B that have received the control signal from the transmitting terminal 2A is returning an ACK signal during the distance measurement period of the transmitting terminal 2A. As described above, in this embodiment, in order to prevent collision of ACK signals, a terminal-specific waiting time or a random waiting time is provided in each of the receiving terminals 1A and 1B.
　図１４の測距シーケンスでは、送信端末２Ｂは、送信端末２Ａの計測期間中に、測距信号の送信を試みる状態にあるが、計測期間（Ｔｐ秒）中に、送信端末２Ａから送信された制御信号が受信されたため、送信端末２Ａの測距シーケンスが終わるまで、自端末の測距信号の送信を待機する。ところで、２つの送信端末２Ａ及び２Ｂの距離が遠く離れ、互いの制御信号を受信できない状態（隠れ端末状態）にある場合、送信端末２Ａの制御信号を受信できない送信端末２Ｂは、自身の測距信号の送信シーケンスを直ちに開始してしまう可能性がある。しかし、本実施例の場合、送信端末２Ｂは、制御信号を受信できなくても受信端末が送信したＡＣＫ信号の受信により、隠れ端末状態にある送信端末２Ａの計測期間中であることを知り、測距信号の送信を計測期間の終了まで待機することができる。 In the ranging sequence of FIG. 14, the transmitting terminal 2B is in a state of attempting to transmit a ranging signal during the measuring period of the transmitting terminal 2A, but transmitted from the transmitting terminal 2A during the measuring period (Tp seconds). Since the control signal has been received, transmission of the distance measurement signal of the own terminal is waited until the distance measurement sequence of the transmission terminal 2A is completed. By the way, when the distance between the two transmission terminals 2A and 2B is so far away that they cannot receive each other's control signal (hidden terminal state), the transmission terminal 2B that cannot receive the control signal of the transmission terminal 2A There is a possibility that the signal transmission sequence starts immediately. However, in the case of the present embodiment, the transmitting terminal 2B knows that it is during the measurement period of the transmitting terminal 2A in the hidden terminal state by receiving the ACK signal transmitted by the receiving terminal even if it cannot receive the control signal, Transmission of the ranging signal can be waited until the end of the measurement period.
　（５）制御信号内に含まれる情報
　図１５に、ＡＣＫ信号に含めて好適な情報の例を示す。図１５は、ＡＣＫ信号に、残り計測期間長、ＡＣＫ信号の送信直前に計算された距離又は位置の測定結果（最新値）、相対速度の測定結果が含まれる場合の例である。なお、残り計測期間長は、送信端末から受信した制御信号に含まれていた残り計測期間長に基づいて計算される。 (5) Information included in control signal FIG. 15 shows an example of suitable information included in the ACK signal. FIG. 15 shows an example in which the ACK signal includes the remaining measurement period length, the distance or position measurement result (latest value) calculated immediately before transmission of the ACK signal, and the relative speed measurement result. The remaining measurement period length is calculated based on the remaining measurement period length included in the control signal received from the transmission terminal.
　（６）計測期間の最適化
　図１６に、距離又は位置（最新値）及び相対速度測定結果の測距シーケンス例を示す。図１６に示すシーケンス例では、送信端末２Ａ（２Ｂ）は、ＡＣＫ信号より直前回の測距シーケンス又は前回までの測距シーケンスで測定された距離又は位置測定結果と相対速度結果から今回の測距シーケンスにおける測距信号の伝搬時間を推測し、測距信号の受信に必要な計測期間の情報を制御信号に含めて送信する。この制御信号の受信により、受信端末１Ａ（１Ｂ）は、これから到来する測距信号の計測期間を短縮することができる。 (6) Optimization of Measurement Period FIG. 16 shows a distance measurement sequence example of distance or position (latest value) and relative speed measurement results. In the sequence example shown in FIG. 16, the transmitting terminal 2A (2B) determines the current distance measurement from the distance or position measurement result measured in the distance measurement sequence immediately before the ACK signal or the distance measurement sequence up to the previous time and the relative speed result. The propagation time of the distance measurement signal in the sequence is estimated, and information on the measurement period necessary for receiving the distance measurement signal is included in the control signal and transmitted. By receiving this control signal, the receiving terminal 1A (1B) can shorten the measurement period of the distance measurement signal coming from now.
　また、計測期間の情報を制御信号に含める場合、当該制御信号を受信した他の送信端末においても、短縮された計測期間を知ることができ、他の送信端末から送信された制御信号の受信後に設ける待機時間を最適化することができる。例えば実施例１の場合、計測期間は、最大検知距離を想定した計測期間（図１６のＴｐｍax）に一律に設定されている。このため、送信端末と受信端末の距離が近い場合には、無駄な計測時間が発生する。 In addition, when information on the measurement period is included in the control signal, the other transmission terminal that has received the control signal can also know the shortened measurement period, and after receiving the control signal transmitted from the other transmission terminal The waiting time to be provided can be optimized. For example, in the case of Example 1, the measurement period is uniformly set to the measurement period (Tpmax in FIG. 16) assuming the maximum detection distance. For this reason, when the distance between the transmission terminal and the reception terminal is short, useless measurement time occurs.
　しかし、本実施例のように、制御信号に計測期間の情報を含めると、Ｔｐｍａｘの経過を待つことなく（短縮された計測期間の後）、他の送信端末による測距信号の送信が可能となり、効率よく距離又は位置を測定することができるようになる。勿論、計測期間の削減により、受信端末における測距信号の検知に必要な計算量も削減される。 However, if information on the measurement period is included in the control signal as in this embodiment, it becomes possible to transmit the distance measurement signal by another transmission terminal without waiting for the elapse of Tpmax (after the shortened measurement period). The distance or position can be measured efficiently. Of course, by reducing the measurement period, the amount of calculation required to detect the distance measurement signal at the receiving terminal is also reduced.
　（７）まとめ
　本実施例に係る距離検知システム及び位置検知システムの採用により、送信端末同士が隠れ端末状態にある場合にも、測距信号同士の衝突を未然に防ぐことができる。また、本実施例の場合には、受信端末によるＡＣＫ信号の送信により、距離の測定が成功したか否かを送信端末側で知ることができ、よりロバストな距離検知システム及び位置検知システムを実現できる。また、本実施例の場合には、直前回の測距シーケンスにおける距離測定結果や相対速度結果をＡＣＫ信号に含めて送信端末に伝達することにより、次回の測距シーケンスにおける測距信号の伝搬時間を予め推測することが可能となり、計測期間の削減と、これに伴う単位時間当たりの測定回数の増加を実現できる。なお、本実施例の場合、ＡＣＫ信号の送信に無線（電波）を使用するため、超音波を使用する測距信号との衝突のおそれはない。 (7) Summary By adopting the distance detection system and the position detection system according to the present embodiment, it is possible to prevent a collision between distance measurement signals even when the transmission terminals are in a hidden terminal state. In the case of the present embodiment, the transmitting terminal can know whether or not the distance measurement has succeeded by transmitting an ACK signal from the receiving terminal, thereby realizing a more robust distance detection system and position detection system. it can. In the case of the present embodiment, the distance measurement signal propagation time in the next distance measurement sequence is transmitted by including the distance measurement result and the relative speed result in the previous distance measurement sequence in the ACK signal and transmitting them to the transmitting terminal. Can be estimated in advance, and the measurement period can be reduced and the number of measurements per unit time can be increased accordingly. In the case of the present embodiment, since radio (radio wave) is used for transmitting the ACK signal, there is no possibility of collision with a distance measurement signal using ultrasonic waves.
　［実施例３］
　本実施例では、距離情報を用いた測定シーケンスの効率化について説明する。 [Example 3]
In this embodiment, the efficiency of the measurement sequence using the distance information will be described.
　（１）システム構成
　本実施例で想定する距離検知システム及び位置検出システムも、実施例１で説明した距離検知システム（図１）及び距離検出システム（図２、図１１）と同様であり、当該システムを構成する送信端末と受信端末の構成も実施例２と同様である。相違点は、送信端末から送信される制御信号に、各受信端末に対する自身の距離又は位置情報、又は、それらに基づいて計算された各受信端末への想定伝搬時間情報を含めることである。 (1) System configuration The distance detection system and the position detection system assumed in this embodiment are also the same as the distance detection system (FIG. 1) and the distance detection system (FIG. 2 and FIG. 11) described in the first embodiment. The configurations of the transmission terminal and the reception terminal constituting the system are the same as those in the second embodiment. The difference is that the control signal transmitted from the transmitting terminal includes its own distance or position information with respect to each receiving terminal, or estimated propagation time information to each receiving terminal calculated based on them.
　（２）制御信号内に含まれる情報
　図１７に、制御信号に含まれる情報の例を示す。図１０に示した実施例１の場合との違いは、想定伝搬時間情報（受信端末１における想定到達時刻、受信端末２における想定到達時刻、受信端末３における想定到達時刻）が含まれる点である。 (2) Information included in control signal FIG. 17 shows an example of information included in the control signal. The difference from the case of the first embodiment shown in FIG. 10 is that the estimated propagation time information (the estimated arrival time at the receiving terminal 1, the estimated arrival time at the receiving terminal 2, and the estimated arrival time at the receiving terminal 3) is included. .
　（３）送信端末の動作
　図１８に、本実施例で使用する送信端末の動作例を示す。図１８に示す処理は、図１２における必要待機時間の計算及び待機ステップ（Ｓ７）で実行される。制御部１１は、送信端末が自身の測距信号の送信前に他の送信端末から送信された制御信号を検出した場合、当該他の送信端末から送信される測距信号が受信端末に到達する時間を、受信した制御信号に含まれる伝搬時間情報と測距信号の送信時刻情報に基づいて推測する（Ｓ４１）。次に、制御部１１は、自身と受信端末との距離測定結果若しくは位置測定結果、又は、自身と受信端末との相対速度測定結果に基づいて、自身の測距信号の伝搬時間を推定する（Ｓ４２）。この後、制御部１１は、Ｓ４１及びＳ４３で求めた値に基づいて、自身の測距信号の送信に必要な待機時間を算出する（Ｓ４３）。 (3) Operation of Transmission Terminal FIG. 18 shows an operation example of the transmission terminal used in this embodiment. The processing shown in FIG. 18 is executed in the calculation of the necessary standby time and the standby step (S7) in FIG. When the transmission terminal detects a control signal transmitted from another transmission terminal before the transmission terminal transmits its distance measurement signal, the control unit 11 receives the distance measurement signal transmitted from the other transmission terminal. The time is estimated based on the propagation time information included in the received control signal and the transmission time information of the ranging signal (S41). Next, the control unit 11 estimates the propagation time of its own ranging signal based on the distance measurement result or position measurement result between itself and the receiving terminal, or the relative velocity measurement result between itself and the receiving terminal ( S42). Thereafter, the control unit 11 calculates a standby time required for transmission of its own ranging signal based on the values obtained in S41 and S43 (S43).
　（４）測距シーケンス
　図１９に、本実施例に係る通信機能を備える送信端末及び受信端末によって実現される測距シーケンスの例を示す。なお、図１９は、図１に示す位置検出システムのように、２つの送信端末２Ａ、２Ｂが１つの受信端末１に対して測距信号をそれぞれ送信する場合を想定するものである。本実施例の場合も、送信端末２Ｂは、送信端末２Ａの測距信号の計測期間中に測距信号の送信を試みるが、送信端末２Ａに由来する制御信号が検出されている。しかし、受信端末２Ｂは、上述した手順により、ただちに測距信号を送信しても衝突はないと判定し、計測期間Ｔｐの終了を待たずに、自身の測距信号の送信を開始している。 (4) Ranging Sequence FIG. 19 shows an example of a ranging sequence realized by a transmitting terminal and a receiving terminal having a communication function according to this embodiment. Note that FIG. 19 assumes a case in which two transmission terminals 2A and 2B transmit distance measurement signals to one reception terminal 1 as in the position detection system shown in FIG. Also in the case of the present embodiment, the transmission terminal 2B tries to transmit the distance measurement signal during the measurement period of the distance measurement signal of the transmission terminal 2A, but the control signal derived from the transmission terminal 2A is detected. However, the receiving terminal 2B determines that there is no collision even if it immediately transmits a distance measurement signal according to the above-described procedure, and starts transmitting its distance measurement signal without waiting for the end of the measurement period Tp. .
　（５）まとめ
　本実施例に係る距離検知システム及び位置検知システムの採用により、受信端末が他の送信端末の測距のために確保した計測期間Ｔｐの終了を待つことなく、自身の測距信号を送信することができる。結果的に、単位時間当たりの測定回数を増やすことができる。 (5) Summary By adopting the distance detection system and the position detection system according to the present embodiment, the receiving terminal does not wait for the end of the measurement period Tp secured for the distance measurement of the other transmission terminal, and its own distance measurement signal. Can be sent. As a result, the number of measurements per unit time can be increased.
　［実施例４］
　本実施例では、測距信号の送信にスペクトル拡散技術を適用する場合について説明する。 [Example 4]
In the present embodiment, a case where a spread spectrum technique is applied to transmission of a ranging signal will be described.
　（１）システム構成
　本実施例で想定する距離検知システム及び位置検出システムも、実施例１で説明した距離検知システム（図１）及び位置検出システム（図２、図１１）と同様であり、当該システムを構成する送信端末と受信端末の構成も実施例１と同様である。ただし、送信端末の超音波送信部１５（図４）にスペクトル拡散処理機能を搭載する点、受信端末のタイミング検出部２３（図６）にスペクトル拡散処理機能を搭載する点で相違する。 (1) System configuration The distance detection system and the position detection system assumed in this embodiment are the same as the distance detection system (FIG. 1) and the position detection system (FIGS. 2 and 11) described in the first embodiment. The configurations of the transmission terminal and the reception terminal constituting the system are the same as those in the first embodiment. However, the difference is that the spread spectrum processing function is mounted on the ultrasonic transmission unit 15 (FIG. 4) of the transmission terminal, and the spread spectrum processing function is mounted on the timing detection unit 23 (FIG. 6) of the reception terminal.
　（２）送信端末の構成
　図２０に、本実施例で使用する送信端末の超音波送信部１５の機能構成を示す。本実施例における超音波送信部１５は、拡散処理部４１、変調部４２、駆動回路部４３で構成される。拡散処理部４１は、Ｍ系列やＧｏｌd符号等の拡散パルス列を生成する。変調部４２は、上記拡散パルス列を所望のキャリア周波数で変調する。変調方式は、ＢＰＳＫ、ＱＰＳＫ、ＭＳＫ等に限定されるものではない。生成された変調信号は、駆動回路部４３による超音波変換素子１７の駆動を通じ、空間に放射される。 (2) Configuration of Transmission Terminal FIG. 20 shows a functional configuration of the ultrasonic transmission unit 15 of the transmission terminal used in this embodiment. The ultrasonic transmission unit 15 in this embodiment includes a diffusion processing unit 41, a modulation unit 42, and a drive circuit unit 43. The spread processing unit 41 generates a spread pulse train such as an M sequence or a Gold code. The modulator 42 modulates the spread pulse train with a desired carrier frequency. The modulation method is not limited to BPSK, QPSK, MSK, or the like. The generated modulation signal is radiated to the space through the driving of the ultrasonic transducer 17 by the drive circuit unit 43.
　なお、本実施例における無線送信制御部１３は、制御信号データを生成する際に、上記拡散系列情報を含める。送信端末のその他の動作は、前述した実施例における送信端末の動作と同様である。 Note that the radio transmission control unit 13 in the present embodiment includes the spreading sequence information when generating control signal data. Other operations of the transmitting terminal are the same as those of the transmitting terminal in the above-described embodiment.
　（３）受信端末の構成
　図２１に、本実施例で使用する受信端末の構成例を示す。図２１には、図６との対応部分に同一符号を付して示す。相違点は、タイミング検出部５１と制御部５２である。制御部５２は、制御信号を受信した際に、制御信号から抽出される測距信号の計測期間及び測距信号の送信時刻をタイミング検出部５１に提供する。同時に、制御部５２は、制御信号から拡散系列情報を抽出し、タイミング検出部５１に提供する。タイミング検出部５１は、上記計測期間及び測距信号送信時刻に基づいて、測距信号の伝搬時間を計算する。また、その際に周波数シフトを検出することも可能である。 (3) Configuration of Receiving Terminal FIG. 21 shows a configuration example of the receiving terminal used in this embodiment. In FIG. 21, parts corresponding to those in FIG. The difference is the timing detection unit 51 and the control unit 52. When receiving the control signal, the control unit 52 provides the timing detection unit 51 with the measurement period of the distance measurement signal extracted from the control signal and the transmission time of the distance measurement signal. At the same time, the control unit 52 extracts spreading sequence information from the control signal and provides it to the timing detection unit 51. The timing detection unit 51 calculates the propagation time of the distance measurement signal based on the measurement period and the distance measurement signal transmission time. At that time, it is also possible to detect a frequency shift.
　図２２にタイミング検出部５１の機能構成を示す。図２２には、図７との対応部分に同一符号を付して示す。サンプリング部３１は、制御部５２から提供される計測期間の間だけ受信信号をサンプリングする。周波数推定・相関部６１は、サンプリングされたデータに対し、キャリア周波数の周波数シフトの推定処理と逆拡散処理を実行する。逆拡散処理の際に使用する拡散系列は、制御部５２から提供される。さらに、時間差検出部３３は、測距信号と制御信号の受信時刻差、又は、当該受信時刻差と測距信号の送信時刻情報とに基づいて、測距信号の伝搬時間を検出する。受信端末のその他の動作は、前述した実施例の動作と同様である。 FIG. 22 shows a functional configuration of the timing detection unit 51. In FIG. 22, parts corresponding to those in FIG. The sampling unit 31 samples the received signal only during the measurement period provided from the control unit 52. The frequency estimation / correlation unit 61 performs a frequency shift estimation process and a despreading process on the sampled data. A spreading sequence used in the despreading process is provided from the control unit 52. Furthermore, the time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal. Other operations of the receiving terminal are the same as those of the above-described embodiment.
　（４）測距シーケンス
　（４－１）シーケンス１
　図２３に、本実施例で実現される測距シーケンスの一例を示す。図２３は、図１に示す距離検知システムを前提とするものであり、２つの送信端末２Ａ及び２Ｂが１つの受信端末１に対して測距信号を送信する場合について表している。送信端末２Ａの計測期間中、受信端末１は、制御信号に含まれる拡散系列｛Ａｉ｝を用いて測距信号を待ち受けし、受信された測距信号の伝搬時間を求める。同様に、送信端末２Ｂの計測期間中、受信端末１は、制御信号に含まれる拡散系列｛Ｂｉ｝を用いて測距信号を待ち受けし、受信された測距信号の伝搬時間を求める。 (4) Ranging sequence (4-1) Sequence 1
FIG. 23 shows an example of a distance measuring sequence realized in this embodiment. FIG. 23 is based on the distance detection system shown in FIG. 1, and shows a case where two transmission terminals 2 </ b> A and 2 </ b> B transmit ranging signals to one reception terminal 1. During the measurement period of the transmission terminal 2A, the reception terminal 1 waits for the distance measurement signal using the spreading sequence {Ai} included in the control signal, and obtains the propagation time of the received distance measurement signal. Similarly, during the measurement period of the transmitting terminal 2B, the receiving terminal 1 waits for a ranging signal using the spreading sequence {Bi} included in the control signal, and obtains the propagation time of the received ranging signal.
　（４－２）シーケンス２
　前述した動作は、実施例１と同様な伝送方式であるが、拡散系列を使用する本実施例のシステムでは、時間的な衝突を防ぐための制御信号の繰り返し送信は必ずしも必要でない。図２４に、そのシーケンス例を示す。このシーケンス例の場合、送信端末２Ａ及び２Ｂは、測距信号の送信につき１回のみ制御信号を送信する。制御信号にはそれぞれの拡散系列が含まれる。受信端末１は、それぞれの計測期間に制御信号に含まれる拡散系列で受信処理を行う。 (4-2) Sequence 2
The above-described operation is the same transmission method as in the first embodiment, but in the system of this embodiment using a spreading sequence, it is not always necessary to repeatedly transmit a control signal to prevent temporal collision. FIG. 24 shows an example of the sequence. In the case of this sequence example, the transmission terminals 2A and 2B transmit the control signal only once for transmission of the distance measurement signal. The control signal includes each spreading sequence. The receiving terminal 1 performs reception processing with the spreading sequence included in the control signal in each measurement period.
　お互いの拡散系列として相互相関が低いものが選ばれている場合、２つの測距信号の受信端末における受信タイミングが時間的に衝突したとしても、２つの測距信号を互いに分離して受信できる。なお、複数の送信端末からの測距信号の計測時間が時間的に重なる場合でも、周波数推定・相関部６１が複数の逆拡散回路を並列に備えていれば、各測距信号を同時に計算することができる。また、周波数推定・相関部６１が複数の逆拡散回路を１つしか搭載しない場合でも、サンプリングデータを不図示の記憶領域に蓄積しておき、それぞれの計測期間が終わった後、サンプリングデータに対する逆拡散処理を時間順次に実行すれば、拡散系列が異なる測距信号の受信時刻を求めることができる。なお、図２４では、制御信号を１回しか送信していないが、１番目の制御信号が受信端末１で受信できない場合も想定して、複数回（少なくとも２回）、制御信号を送信してもよい。 When a low cross-correlation sequence is selected as the mutual spreading sequence, the two ranging signals can be received separately even if the reception timings of the two ranging signals at the receiving terminal collide in time. Even when the measurement signals of the ranging signals from a plurality of transmission terminals overlap in time, if the frequency estimation / correlation unit 61 includes a plurality of despreading circuits in parallel, each ranging signal is calculated simultaneously. be able to. Even when the frequency estimation / correlation unit 61 includes only one despreading circuit, the sampling data is accumulated in a storage area (not shown), and after each measurement period, the inverse of the sampling data is performed. If the spreading process is executed in time sequence, it is possible to obtain the reception times of ranging signals having different spreading sequences. In FIG. 24, the control signal is transmitted only once. However, assuming that the first control signal cannot be received by the receiving terminal 1, the control signal is transmitted a plurality of times (at least twice). Also good.
　（５）制御信号内に含まれる情報
　図２５に、送信端末から受信端末に送信される制御信号に含めて好適な情報の例を示す。図２５は、制御信号に拡散系列の情報が含まれる点で、図１０に示す例と異なっている。 (5) Information included in control signal FIG. 25 shows an example of information suitable for inclusion in a control signal transmitted from a transmitting terminal to a receiving terminal. FIG. 25 differs from the example shown in FIG. 10 in that spreading sequence information is included in the control signal.
　（６）周波数推定・相関部６１の動作
　図２６に、周波数推定・相関部６１で実行される周波数シフト量推定処理及び逆拡散処理に関連する波形例を示す。図２６の上段に示す波形は、拡散されたパルス系列を示している。ただし、この波形は変調されていないベースバンド信号である。中段に示す波形は、同じ拡散系列を持つ参照パルス列と畳み込み演算した後に得られる波形である。この例では、周波数シフトはないものとしている。拡散系列のタイミングが一致した時点にピークが現れており、これが逆拡散処理の計算結果である。下段に示す波形は、前述の逆拡散処理のピーク値を参照信号のキャリア周波数をオフセットさせて計算した結果をプロットしたものである。この例では、受信波形に周波数シフトがないので、周波数オフセット０でピークが現れている。前述の信号処理により、周波数シフト量及び伝搬遅延量を計算することができる。 (6) Operation of Frequency Estimation / Correlation Unit 61 FIG. 26 shows waveform examples related to frequency shift amount estimation processing and despreading processing executed by the frequency estimation / correlation unit 61. The waveform shown in the upper part of FIG. 26 shows a spread pulse sequence. However, this waveform is an unmodulated baseband signal. The waveform shown in the middle stage is a waveform obtained after convolution with a reference pulse train having the same spreading sequence. In this example, it is assumed that there is no frequency shift. A peak appears when the timings of the spreading sequences match, and this is the calculation result of the despreading process. The waveform shown in the lower part is a plot of the result of calculating the peak value of the above despreading process by offsetting the carrier frequency of the reference signal. In this example, since there is no frequency shift in the received waveform, a peak appears at a frequency offset of 0. The frequency shift amount and the propagation delay amount can be calculated by the signal processing described above.
　（７）まとめ
　本実施例に係る距離検知システム及び位置検知システムの採用により、複数の送信端末が異なる拡散系列を用いて測距信号を同時に送信する場合でも、制御信号に含まれる拡散系列を用いてサンプリングデータを逆拡散処理すれば各測距信号を受信できるため、受信端末側における計算処理を大幅に削減することができる。一般的な技術では、受信される可能性のある全ての拡散系列についての逆拡散処理を受信端末で行う必要があり、受信端末に搭載する回路規模が増大、又は、計算時間が増大する問題がある。しかし、本実施例では、拡散系列が制御信号を通じて先に通知されるため、受信端末の回路規模を複雑化することなしに、符号多重測距動作と時分割多重測距動作を同時に実現でき、単位時間当たりの測距回数を増加させることができる。 (7) Summary By adopting the distance detection system and the position detection system according to the present embodiment, even when a plurality of transmitting terminals transmit ranging signals simultaneously using different spreading sequences, the spreading sequences included in the control signal are used. If the sampling data is subjected to despreading processing, each ranging signal can be received, so that the calculation processing on the receiving terminal side can be greatly reduced. In a general technique, it is necessary to perform despreading processing on all spreading sequences that may be received at the receiving terminal, and there is a problem that the circuit scale mounted on the receiving terminal increases or the calculation time increases. is there. However, in this embodiment, since the spreading sequence is notified first through the control signal, the code multiplex ranging operation and the time division multiplex ranging operation can be realized simultaneously without complicating the circuit scale of the receiving terminal, The number of distance measurement per unit time can be increased.
　［実施例５］
　本実施例では、角度検出機能を有する受信端末を含むシステムについて説明する。具体的には、１つの受信端末に２つの超音波変換素子を搭載し、受信信号の位相差から受信端末に対する送信端末の方位を推定する角度検出機能を搭載する例について説明する。 [Example 5]
In this embodiment, a system including a receiving terminal having an angle detection function will be described. Specifically, an example will be described in which two ultrasonic transducers are mounted on one receiving terminal and an angle detection function for estimating the azimuth of the transmitting terminal relative to the receiving terminal from the phase difference of the received signals.
　（１）システム構成
　本実施例で想定する距離検知システム及び位置検出システムは、いずれも実施例１で説明した距離検知システム（図１）及び位置検出システム（図２、図１１）と同様であり、当該システムを構成する送信端末の構成も前述した実施例１～４と同様である。ただし、以下の説明では、送信端末は実施例４で説明した送信端末（すなわち、拡散系列を用いて測距信号を送信する機能を搭載する端末）について説明する。前述の実施例との違いは、受信端末の構成である。 (1) System Configuration The distance detection system and the position detection system assumed in this embodiment are the same as the distance detection system (FIG. 1) and the position detection system (FIGS. 2 and 11) described in the first embodiment. The configuration of the transmission terminal that constitutes the system is the same as in the first to fourth embodiments. However, in the following description, the transmission terminal will be described with respect to the transmission terminal described in the fourth embodiment (that is, a terminal equipped with a function of transmitting a ranging signal using a spread sequence). The difference from the above-described embodiment is the configuration of the receiving terminal.
　（２）受信端末の構成
　図２７に、本実施例で使用する受信端末の構成例を示す。図２７には、図２１との対応部分に同一符号を付して示す。本実施例における受信端末は、２つの超音波変換素子１７Ａ、１７Ｂ、１つの無線変換素子１８、２つの超音波受信回路２１Ａ、２１Ｂ、１つの無線送受信部２２、タイミング・位相差検出部７１、制御部５２、データ処理部７２で構成される。これらのうち、超音波変換素子１７Ａ、１７Ｂ、無線変換素子１８、超音波受信回路２１Ａ、２１Ｂ、無線送受信部２２、制御部５２は、実施例４の受信端末の各構成要素と同様の処理を実行する。 (2) Configuration of Receiving Terminal FIG. 27 shows a configuration example of the receiving terminal used in this embodiment. In FIG. 27, parts corresponding to those in FIG. The receiving terminal in this embodiment includes two ultrasonic transducers 17A and 17B, one radio transducer 18, two ultrasonic receivers 21A and 21B, one radio transmitter / receiver 22, a timing / phase difference detector 71, A control unit 52 and a data processing unit 72 are included. Among these, the ultrasonic conversion elements 17A and 17B, the wireless conversion element 18, the ultrasonic reception circuits 21A and 21B, the wireless transmission / reception unit 22, and the control unit 52 perform the same processing as each component of the reception terminal of the fourth embodiment. Execute.
　図２８に、タイミング・位相差検出部７１の機能構成を示す。図２８には、図２２との対応部分に同一符号を付して示す。タイミング・位相差検出部７１は、２つのサンプリング部３１Ａ、３１Ｂ、逆拡散部８１、周波数推定・相関部６１、位相差検出部８２、時間差検出部３３を含む。サンプリング部３１Ａ及び３１Ｂは、いずれも制御部５２から提供される計測期間の間だけ受信信号をサンプリングする。 FIG. 28 shows a functional configuration of the timing / phase difference detection unit 71. In FIG. 28, parts corresponding to those in FIG. The timing / phase difference detection unit 71 includes two sampling units 31A and 31B, a despreading unit 81, a frequency estimation / correlation unit 61, a phase difference detection unit 82, and a time difference detection unit 33. Sampling units 31 </ b> A and 31 </ b> B both sample the received signal during the measurement period provided from control unit 52.
　周波数推定・相関部６１は、サンプリング部３１Ｂでサンプリングされたサンプリングデータを入力し、当該サンプリングデータについてキャリア周波数の偏差推定処理と逆拡散処理を実行する。なお、逆拡散処理の際に用いられる拡散系列は、制御部５２から提供される。時間差検出部３３は、測距信号と制御信号の受信時刻差、又は、当該受信時刻差と測距信号の送信時刻情報とに基づいて、測距信号の伝搬時間を検出する。 The frequency estimation / correlation unit 61 inputs the sampling data sampled by the sampling unit 31B, and executes carrier frequency deviation estimation processing and despreading processing on the sampling data. Note that the spreading sequence used in the despreading process is provided from the control unit 52. The time difference detection unit 33 detects the propagation time of the distance measurement signal based on the reception time difference between the distance measurement signal and the control signal or the reception time difference and the transmission time information of the distance measurement signal.
　逆拡散部８１は、周波数推定・相関部６１で求められた周波数オフセットを用い、サンプリング部３１Ａから入力されるサンプリングデータを逆拡散処理する。位相差検出部８２は、逆拡散部８１及び周波数推定・相関部６１で求められた結果に基づいて、受信信号の位相差（到達時間差）を計算する。 The despreading unit 81 uses the frequency offset obtained by the frequency estimation / correlation unit 61 to despread the sampling data input from the sampling unit 31A. The phase difference detection unit 82 calculates the phase difference (arrival time difference) of the received signals based on the results obtained by the despreading unit 81 and the frequency estimation / correlation unit 61.
　データ処理部７２は、タイミング・位相差検出部７１で計算された時間情報を測距信号の伝搬距離に変換する処理を実行する。また、データ処理部７２は、位相差検出部８２で求められた位相差情報を測距信号の到来方向に変換する。さらに、必要に応じ、データ処理部７２は、ドップラーシフトの原理より、周波数推定値から受信端末に対する送信端末の相対速度を計算する。さらに、必要に応じ、データ処理部７２は、それらのデータを他の端末に対してＩＤ情報と共に伝送する。 The data processing unit 72 executes processing for converting the time information calculated by the timing / phase difference detection unit 71 into the propagation distance of the ranging signal. In addition, the data processing unit 72 converts the phase difference information obtained by the phase difference detection unit 82 into the arrival direction of the distance measurement signal. Furthermore, as necessary, the data processing unit 72 calculates the relative speed of the transmitting terminal with respect to the receiving terminal from the frequency estimation value based on the principle of Doppler shift. Furthermore, if necessary, the data processing unit 72 transmits these data together with ID information to other terminals.
　（３）まとめ
　　本実施例に係る距離検知システム及び位置検知システムの採用により、距離と同時に、測距信号の到来方向を簡易な受信機構成で検出することができる。従って、図１に示す距離検知システム構成において、受信端末が１つしか存在しない場合でも、受信端末に対する送信端末の位置を推定することが可能となる。また、図２に示す位置検知システムのように、受信端末が２つ以上存在する場合でも、位置検知の成功確率の向上や位置検知精度の向上を実現できる。 (3) Summary By employing the distance detection system and the position detection system according to the present embodiment, the arrival direction of the distance measurement signal can be detected with a simple receiver configuration at the same time as the distance. Therefore, in the distance detection system configuration shown in FIG. 1, even when there is only one receiving terminal, it is possible to estimate the position of the transmitting terminal with respect to the receiving terminal. Further, even when there are two or more receiving terminals as in the position detection system shown in FIG. 2, it is possible to improve the success probability of position detection and improve the position detection accuracy.
　［他の実施例］
　本発明は、上述した実施例の構成に限定されるものでなく、様々な変形例を含んでいる。例えば上述した実施例は、本発明を分かりやすく説明するために、一部の実施例について詳細に説明したものであり、必ずしも説明した全ての構成を備える必要は無い。また、ある実施例の一部を他の実施例の一部構成と置き換えることが可能であり、ある実施例の構成に他の実施例の構成を加えることも可能である。また、各実施例の構成に他の構成を追加し、又は、各実施例の一部構成を他の構成で置換し、又は各実施例の一部構成を削除することも可能である。 [Other embodiments]
The present invention is not limited to the configuration of the embodiment described above, and includes various modifications. For example, in the above-described embodiments, in order to explain the present invention in an easy-to-understand manner, some embodiments are described in detail, and it is not always necessary to include all the configurations described. In addition, a part of one embodiment can be replaced with a part of the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. It is also possible to add other configurations to the configuration of each embodiment, replace a partial configuration of each embodiment with another configuration, or delete a partial configuration of each embodiment.
　また、上述した各構成、機能、処理部、処理手段等は、それらの一部又は全部を、例えば集積回路その他のハードウェアとして実現しても良い。また、上記の各構成、機能等は、それぞれの機能を実現するプログラムをプロセッサが解釈して実行することにより実現しても良い。すなわち、各構成等をソフトウェアにより実現しても良い。この場合、各機能を実現するプログラム、テーブル、ファイル等の情報は、メモリやハードディスク、SSD（Solid State Drive）等の記憶装置、ICカード、SDカード、DVD等の記憶媒体に格納することができる。 In addition, each of the above-described configurations, functions, processing units, processing means, and the like may be partly or entirely realized as, for example, an integrated circuit or other hardware. Each of the above-described configurations, functions, and the like may be realized by a processor interpreting and executing a program that realizes each function. That is, each configuration may be realized by software. In this case, information such as programs, tables, and files for realizing each function can be stored in a storage device such as a memory, a hard disk, an SSD (Solid State Drive), or a storage medium such as an IC card, an SD card, or a DVD. .
　また、制御線や情報線は、説明上必要と考えられるものを示すものであり、製品上必要な全ての制御線や情報線を表すものでない。実際にはほとんど全ての構成が相互に接続されていると考えて良い。 Also, the control lines and information lines indicate what is considered necessary for explanation, and do not represent all control lines and information lines necessary for the product. In practice, it can be considered that almost all components are connected to each other.
　１Ａ、１Ｂ、１Ｃ、１Ｄ…受信端末、２Ａ、２Ｂ、２Ｃ、２Ｄ…送信端末、３…測位装置、１１…制御部、１２…超音波送信制御部、１３…無線送信制御部、１４…制御信号検出部、１５…超音波送信部、１６…無線送受信部、１７、１７Ａ、１７Ｂ…超音波変換素子、１８…無線変換素子、１９…各種センサ、２１…超音波受信部、２２…無線送受信部、２３、５１…タイミング検出部、２４、５２…制御部、２５、７２…データ処理部、３１、３１Ａ、３１Ｂ…サンプリング部、３２…周波数推定部、３３…時間差検出部、４１…拡散処理部、４２…変調部、４３…駆動回路部、６１…周波数推定・相関部、７１…タイミング・位相差検出部、８１…逆拡散部、８２…位相差検出部。 1A, 1B, 1C, 1D ... receiving terminal, 2A, 2B, 2C, 2D ... transmitting terminal, 3 ... positioning device, 11 ... control unit, 12 ... ultrasonic transmission control unit, 13 ... radio transmission control unit, 14 ... control Signal detection unit, 15 ... ultrasonic transmission unit, 16 ... wireless transmission / reception unit, 17, 17A, 17B ... ultrasonic conversion element, 18 ... wireless conversion element, 19 ... various sensors, 21 ... ultrasonic reception unit, 22 ... wireless transmission / reception , 23, 51 ... timing detection unit, 24, 52 ... control unit, 25, 72 ... data processing unit, 31, 31A, 31B ... sampling unit, 32 ... frequency estimation unit, 33 ... time difference detection unit, 41 ... diffusion processing Reference numeral 42: Modulation unit 43: Drive circuit unit 61 Frequency estimation / correlation unit 71 Timing / phase difference detection unit 81 Despreading unit 82 Phase difference detection unit

Claims (14)

  1. 　(1)第一の媒体を通じて距離測定のための測距信号を送信する送信部と、(2)第一の媒体の伝送速度よりも伝送速度が速い第二の媒体を通じて制御信号を送受信する送受信部と、(3)前記測距信号の送信に先立つ所定の期間Ｔｃ中に、他の送信端末から送信された制御信号が受信されない場合に、前記測距信号の送信を許容すると共に前記測距信号の送信から計測期間Ｔｐの間、一定間隔Ｔｉ（＜Ｔｃ）毎に前記制御信号を送信させる送信制御部とを有する送信端末と、
    　(1)第一の媒体を通じて測距信号を受信する受信部と、(2)第二の媒体を通じて制御信号を送受信する送受信部と、(3)測距信号の受信時刻と制御信号の受信時刻との差に基づいて測距信号の伝搬時間を算出し、自端末と送信端末との距離を検知するタイミング検出部とを有する受信端末と
    　を有する距離検知システム。     (1) a transmitter for transmitting a distance measurement signal for distance measurement through the first medium; and (2) transmission / reception for transmitting and receiving a control signal through the second medium having a transmission speed higher than the transmission speed of the first medium. (3) When a control signal transmitted from another transmitting terminal is not received during a predetermined period Tc prior to transmission of the ranging signal, the transmission of the ranging signal is permitted and the ranging A transmission terminal having a transmission control unit that transmits the control signal at regular intervals Ti (<Tc) during the measurement period Tp from the transmission of the signal;
    (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) a receiving time of the ranging signal and a receiving time of the control signal A distance detection system comprising: a reception terminal having a timing detection unit that calculates a propagation time of a distance measurement signal based on a difference between the distance measurement signal and a distance between the terminal and the transmission terminal.
  2. 　請求項１に記載の距離検知システムにおいて、
    　前記送信端末の前記送信制御部は、送信端末が持つ固有のＩＤ、対応する測距信号のシーケンス番号、前記測距信号の送信時刻、及び、前記測距信号の計測に必要とされる残りの計測期間長のうち少なくとも１つの情報を含む前記制御信号を送信させる
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    The transmission control unit of the transmission terminal includes a unique ID of the transmission terminal, a corresponding ranging signal sequence number, a transmission time of the ranging signal, and the remaining required for measuring the ranging signal. The distance detection system, wherein the control signal including at least one piece of information in the measurement period length is transmitted.
  3. 　請求項１に記載の距離検知システムにおいて、
    　前記送信端末の前記送信制御部は、他の送信端末から送信される前記制御信号に前記測距信号に対する残りの計測期間長を規定する情報が含まれる場合にあって、前記所定の期間Ｔｃ中に、前記他の送信端末から送信された前記制御信号が受信されたとき、前記残りの計測期間長に基づいて前記測距信号を送信するまでの待機時間Ｔｗを計算する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    The transmission control unit of the transmission terminal includes a case in which the control signal transmitted from another transmission terminal includes information defining a remaining measurement period length for the distance measurement signal, and is in the predetermined period Tc. In addition, when the control signal transmitted from the other transmitting terminal is received, a waiting time Tw until the ranging signal is transmitted is calculated based on the remaining measurement period length. Detection system.
  4. 　請求項１に記載の距離検知システムにおいて、
    　前記受信端末は、前記送信端末から前記制御信号を受信したとき、その受信時刻より各受信端末に固有の待機時間又はランダムに与えられる待機時間が経過した後、前記第二の媒体を通じて確認信号（ＡＣＫ信号）を送信させる制御部を更に有する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    When the receiving terminal receives the control signal from the transmitting terminal, after a waiting time specific to each receiving terminal or a randomly given waiting time elapses from the receiving time, a confirmation signal ( The distance detection system further includes a control unit that transmits an ACK signal.
  5. 　請求項４に記載の距離検知システムにおいて、
    　前記送信端末の前記送信制御部は、他の送信端末から送信される前記制御信号に前記測距信号に対する残りの計測期間長を規定する情報が含まれる場合にあって、前記所定の期間Ｔｃ中に、前記他の送信端末から送信された制御信号又は前記残り計測期間長を規定する情報を含む前記確認信号（ＡＣＫ信号）が受信されたとき、前記残りの計測期間長に基づいて前記測距信号を送信するまでの待機時間Ｔｗを計算する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 4,
    The transmission control unit of the transmission terminal includes a case in which the control signal transmitted from another transmission terminal includes information defining a remaining measurement period length for the distance measurement signal, and is in the predetermined period Tc. In addition, when the control signal transmitted from the other transmitting terminal or the confirmation signal (ACK signal) including information defining the remaining measurement period length is received, the distance measurement is performed based on the remaining measurement period length. A distance detection system characterized by calculating a waiting time Tw until a signal is transmitted.
  6. 　請求項５に記載の距離検知システムにおいて、
    　前記受信端末は、距離測定結果を含む前記確認信号（ＡＣＫ信号）を送信させる制御部を更に有し、
    　前記送信端末の前記送信制御部は、受信した前記確認信号（ＡＣＫ信号）に含まれる前記距離測定結果に基づいて、次回の測距信号を前記受信端末で受信するための計測期間を計算し、当該計測期間を次回の測距信号に対応する制御信号に含めて送信する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 5,
    The receiving terminal further includes a control unit that transmits the confirmation signal (ACK signal) including a distance measurement result,
    The transmission control unit of the transmitting terminal calculates a measurement period for receiving the next ranging signal at the receiving terminal based on the distance measurement result included in the received confirmation signal (ACK signal), A distance detection system characterized in that the measurement period is included in a control signal corresponding to the next distance measurement signal and transmitted.
  7. 　請求項５に記載の距離検知システムにおいて、
    　前記受信端末は、距離測定結果を含む前記確認信号（ＡＣＫ信号）を送信させる制御部を更に有し、
    　前記送信端末の前記送信制御部は、受信した前記確認信号（前記ＡＣＫ信号）に含まれる前記距離測定結果に基づいて、次回の測距信号が前記受信端末に到達する想定時刻を計算し、当該想定時刻を次回の測距信号に対応する制御信号に含めて送信する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 5,
    The receiving terminal further includes a control unit that transmits the confirmation signal (ACK signal) including a distance measurement result,
    The transmission control unit of the transmitting terminal calculates an estimated time at which a next ranging signal reaches the receiving terminal based on the distance measurement result included in the received confirmation signal (the ACK signal), and A distance detection system characterized in that the estimated time is included in a control signal corresponding to the next ranging signal and transmitted.
  8. 　請求項７に記載の距離検知システムにおいて、
    　前記送信端末の前記送信制御部は、前記所定の期間Ｔｃ中に、他の送信端末から送信された制御信号が受信された場合、当該他の送信端末から受信された前記制御信号に含まれる第１の想定時刻と、自身について計算された第２の想定時刻とに基づいて、次回の測距信号の送信を開始するまでの待機時間Ｔｗを計算する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 7, wherein
    When the control signal transmitted from another transmitting terminal is received during the predetermined period Tc, the transmission control unit of the transmitting terminal includes the control signal received from the other transmitting terminal. A distance detection system that calculates a waiting time Tw until the next transmission of a distance measurement signal is started based on the estimated time of 1 and the second estimated time calculated for itself.
  9. 　請求項７に記載の距離検知システムにおいて、
    　前記受信端末は、受信した前記測距信号のドップラーシフト量を計算して前記送信端末の相対速度を計算するデータ処理部を更に有し、前記送受信部は、計算された前記相対速度を前記確認信号（ＡＣＫ信号）に含めて送信し、
    　前記送信端末の前記送信制御部は、受信した前記相対速度を含めて次回の測距信号が前記受信端末に到達する前記想定時刻を計算する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 7, wherein
    The receiving terminal further includes a data processing unit that calculates a Doppler shift amount of the received ranging signal to calculate a relative speed of the transmitting terminal, and the transmitting / receiving unit checks the calculated relative speed as the confirmation Send it in the signal (ACK signal)
    The distance detection system, wherein the transmission control unit of the transmitting terminal calculates the estimated time at which a next ranging signal reaches the receiving terminal including the received relative speed.
  10. 　請求項１に記載の距離検知システムにおいて、
    　前記受信端末は、前記第一の媒体を通じて前記測距信号を受信する前記受信部を２系統備え、それぞれの系統を通じて受信される前記測距信号の位相差に基づいて前記測距信号の到来方向を計算するデータ処理部を更に有する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    The receiving terminal includes two systems of the reception unit that receives the ranging signal through the first medium, and the arrival direction of the ranging signal based on the phase difference of the ranging signal received through each system A distance detection system, further comprising a data processing unit for calculating.
  11. 　請求項１に記載の距離検知システムにおいて、
    　少なくとも２台の前記送信端末は、それぞれ、自身の位置情報を前記制御信号に含めて送信し、
    　１台の前記受信端末は、前記少なくとも２台の送信端末から受信した前記制御信号に含まれる前記位置情報と、前記タイミング検出部において前記少なくとも２台の送信端末のそれぞれについて検知された前記距離の情報とに基づいて、前記少なくとも２台の送信端末に対する自端末の相対位置を計算するデータ処理部を有する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    At least two of the transmitting terminals each transmit their own position information in the control signal,
    One receiving terminal includes the position information included in the control signal received from the at least two transmitting terminals, and the distance detected for each of the at least two transmitting terminals by the timing detection unit. And a data processing unit that calculates a relative position of the terminal with respect to the at least two transmission terminals based on the information.
  12. 　請求項１に記載の距離検知システムにおいて、
    　同じ送信端末に対する前記距離の情報を、位置情報が既知である少なくとも２台の前記受信端末から入力し、前記少なくとも２台の受信端末に対する前記送信端末の相対位置を計算する測位装置を更に有する
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 1,
    It further has a positioning device that inputs the distance information for the same transmitting terminal from at least two receiving terminals whose position information is known, and calculates the relative position of the transmitting terminal with respect to the at least two receiving terminals. A distance detection system characterized by
  13. 　(1)第一の媒体を通じて距離測定のための測距信号を送信する送信部であって、所定の拡散系列でスペクトラム拡散された測距信号を送信する送信部と、(2)第一の媒体の伝送速度よりも伝送速度が速い第二の媒体を通じて制御信号を送受信する送受信部であって、拡散系列情報を含む制御信号を送信する送受信部と、(3)前記測距信号の送信に先立つ所定の期間Ｔｃ中に、他の送信端末から送信された制御信号が受信されない場合に、前記測距信号の送信を許容する送信制御部とを有する送信端末と、
    　(1)第一の媒体を通じて測距信号を受信する受信部と、(2)第二の媒体を通じて制御信号を送受信する送受信部と、(3)測距信号を制御信号に含まれる拡散系列情報を用いて逆拡散処理すると共に、測距信号の受信時刻と制御信号の受信時刻との差に基づいて測距信号の伝搬時間を算出し、自端末と送信端末との距離を検知するタイミング検出部とを有する受信端末と
    　を有する距離検知システム。     (1) a transmission unit that transmits a ranging signal for distance measurement through the first medium, the transmission unit transmitting a ranging signal that is spectrum-spread by a predetermined spreading sequence; and (2) the first A transmission / reception unit for transmitting / receiving a control signal through a second medium having a transmission rate higher than the transmission rate of the medium, and a transmission / reception unit for transmitting a control signal including spreading sequence information; and (3) for transmission of the ranging signal A transmission terminal having a transmission control unit that allows transmission of the ranging signal when a control signal transmitted from another transmission terminal is not received during a predetermined period Tc prior to
    (1) a receiving unit that receives a ranging signal through the first medium, (2) a transmitting / receiving unit that transmits and receives a control signal through the second medium, and (3) spreading sequence information included in the control signal. Detection of the distance between the terminal and the transmitting terminal by calculating the propagation time of the distance measuring signal based on the difference between the reception time of the distance measurement signal and the reception time of the control signal. A distance detection system having a receiving terminal.
  14. 　請求項１３に記載の距離検知システムにおいて、
    　前記送信端末の前記送信制御部は、前記測距信号の送信から計測期間Ｔｐの間、一定間隔Ｔｉ（＜Ｔｃ）毎に前記制御信号を送信させる
    　ことを特徴とする距離検知システム。     The distance detection system according to claim 13,
    The transmission control unit of the transmission terminal transmits the control signal at regular intervals Ti (<Tc) during the measurement period Tp from the transmission of the distance measurement signal.
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