WO2010010832A1 - Position detecting system, transmission device, reception device, position detecting method, and position detecting program - Google Patents

Position detecting system, transmission device, reception device, position detecting method, and position detecting program Download PDF

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Publication number
WO2010010832A1
WO2010010832A1 PCT/JP2009/062791 JP2009062791W WO2010010832A1 WO 2010010832 A1 WO2010010832 A1 WO 2010010832A1 JP 2009062791 W JP2009062791 W JP 2009062791W WO 2010010832 A1 WO2010010832 A1 WO 2010010832A1
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Prior art keywords
signal
ultrasonic
pseudo
sequence
electromagnetic wave
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PCT/JP2009/062791
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French (fr)
Japanese (ja)
Inventor
潤一 宮本
浩司 梶谷
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日本電気株式会社
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Application filed by 日本電気株式会社 filed Critical 日本電気株式会社
Priority to JP2010521680A priority Critical patent/JP5454475B2/en
Priority to US13/055,819 priority patent/US8750076B2/en
Publication of WO2010010832A1 publication Critical patent/WO2010010832A1/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
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
    • G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
    • G06F3/03545—Pens or stylus
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/043—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves
    • G06F3/0433—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Definitions

  • the present invention relates to a position determination system that determines the position of a moving body using ultrasonic signals, and in particular, a position detection system that makes it possible to accurately and stably determine the position of a moving body using ultrasonic waves,
  • the present invention relates to a transmission device, a reception device, a position detection method, and a position detection program.
  • Patent Document 1 discloses an ultrasonic object measuring apparatus as an example of a related technique of an apparatus that measures distance based on ultrasonic propagation time.
  • the ultrasonic object measuring apparatus described in Patent Document 1 performs transmission by performing frequency spread modulation on a tone burst wave generated from a tone burst wave generator using a pseudo noise signal from a pseudo noise signal generator by a frequency spread modulator. To do.
  • the cross-correlator obtains the cross-correlation between the signal received by the reflected wave and demodulated by the frequency spread signal demodulator and the pseudo noise signal used for frequency spreading. Further, from the correlation level obtained by the correlation level detector 9, the presence or absence of reception of the reflected signal at the object is determined, and the distance is further measured.
  • a transmission tone burst wave is transmitted using a frequency spread modulation signal obtained by sequentially switching a plurality of pseudo-noise signals, and the plurality of tone burst waves are distinguished and discriminated.
  • the ultrasonic signal transmitted from the ultrasonic transmission source uses a frequency that is higher than the audible band that cannot be heard by humans, it must be at least 20 kHz or higher.
  • a so-called speaker is known which electromagnetically drives a small and highly rigid diaphragm.
  • it is difficult to mount on a small mobile body because it is difficult to reduce the size and power consumption is large because of current driving. For this reason, voltage-driven piezoelectric elements are widely used as ultrasonic transmission sources.
  • this piezoelectric element is a voltage driven type, it generally consumes less power, but in order to ensure sufficient sound pressure, it is often used in combination with a resonator with low acoustic impedance.
  • ultrasonic waves can be transmitted with a constant phase, frequency, and gain, but the transmission gain at other frequencies is considerably low, and a modulation method having wideband frequency characteristics such as frequency spread modulation is used. Difficult to do.
  • the position detection system, transmitter, receiver, position that can reduce the influence of the reflected wave of the ultrasonic wave transmitted in the previous period and accurately measure the propagation time of the direct wave that reaches the earliest.
  • the object is to provide a detection method and a position detection program.
  • a position detection system includes a moving body including a transmission unit that transmits an ultrasonic signal modulated based on a pseudorandom signal with high autocorrelation, and a pseudorandom signal that receives the ultrasonic signal and is the same as the pseudorandom signal.
  • a model waveform of the ultrasonic wave modulated by the above is generated, a correlation value is obtained with the received ultrasonic signal, and a correlation value that appears when the ultrasonic signal partially matches the pseudo-random signal model waveform
  • a receiving unit that selects a plurality of corresponding pseudo-random signals from the smaller secondary peak, and the transmitting unit simultaneously transmits an electromagnetic wave signal and an ultrasonic signal modulated based on the selected pseudo-random signal.
  • the reception unit calculates the arrival time of the ultrasonic signal by executing a correlation process between the ultrasonic signal and the ultrasonic model waveform modulated by the pseudo-random signal.
  • the position of the moving body based on the calculated ultrasonic propagation time from the arrival time of the electromagnetic wave signal and the identified arrival time, and the distance between the calculated ultrasonic propagation time and the ultrasonic receiving means.
  • a transmission unit uses a pseudo-random signal that is different for each transmission cycle.
  • a transmission device is a transmission device of a position detection system that receives an ultrasonic signal transmitted from a transmission device by a reception device and detects the position of the transmission device, and is based on a pseudo-random signal having high autocorrelation.
  • a receiving device is a receiving device of a position detection system that receives an ultrasonic signal transmitted from a transmitting device and detects the position of the transmitting device, and has high autocorrelation transmitted from the transmitting device.
  • the first ultrasonic signal modulated by the pseudo-random sequence data is received, the model waveform of the ultrasonic wave modulated by the same pseudo-random signal as the pseudo-random signal is generated, and the correlation with the received ultrasonic signal is generated.
  • a second ultrasonic signal modulated based on the electromagnetic wave signal to be transmitted and the pseudo random signal selected by the receiving device is received, and the second ultrasonic signal and the pseudo random signal are received.
  • the arrival time of the ultrasonic signal is specified by executing correlation processing with the ultrasonic model waveform modulated by the signal, and the propagation time of the ultrasonic wave is calculated from the arrival time of the electromagnetic wave signal and the specified arrival time
  • the position detection program executes a process of transmitting an ultrasonic signal modulated based on a pseudo-random signal having high autocorrelation from a transmission unit of a mobile body to a computer constituting a transmission device provided in the mobile body. Then, the computer constituting the receiving apparatus receives the ultrasonic signal, generates an ultrasonic model waveform modulated by the pseudo-random signal, and performs correlation processing between the model waveform and the received ultrasonic signal.
  • the receiving apparatus is configured to execute a process of simultaneously transmitting the ultrasonic signal, the trigger signal indicating the transmission timing, and the electromagnetic wave signal including the data defining the pseudo-random signal from the moving body at a constant transmission period.
  • the present invention it is possible to accurately calculate the propagation time of the direct wave that reaches the earliest from the ultrasonic wave transmission source without being affected by the reflected wave of the ultrasonic signal.
  • FIG. 1 is a block diagram showing a configuration of a position detection system according to a first embodiment of the present invention.
  • FIG. 1 is a block diagram showing a configuration of a position detection system according to a first embodiment of the present invention.
  • the position detection system according to the present invention is applied to an electronic pen system.
  • a position detection system using ultrasonic propagation time measurement includes an electronic pen 10 as a movable object on which a transmitter 100 is mounted, and a predetermined position away from the electronic pen 10.
  • a receiving device 20 including a receiving unit 200 installed in the device is provided.
  • selection of an M sequence to be used prior to measurement of ultrasonic propagation time hereinafter referred to as an M sequence selection mode
  • the transmission unit 100 of the electronic pen 10 includes a control circuit 101, an M-sequence generation circuit 102, an ultrasonic drive circuit 103, an ultrasonic transmitter 104, a reception trigger drive circuit 105, and a reception trigger transmitter 106.
  • the control circuit 101 determines an M-sequence initial condition based on a characteristic polynomial determined in advance in each transmission cycle, and this initial condition is driven by the M-sequence generation circuit 102 and the reception trigger in a fixed transmission cycle. This is transmitted to the circuit 105.
  • the M-sequence generation unit 102 generates an M-sequence coded bit string that is different for each transmission cycle in accordance with the initial condition sent from the control circuit 101.
  • the ultrasonic drive circuit 103 supplies the M series data generated by the M series generation means 102 to the ultrasonic transmitter 104 as a drive signal for ultrasonic modulation.
  • the ultrasonic transmitter 104 modulates an ultrasonic wave using the drive signal from the ultrasonic drive circuit 103 as a modulation signal, and sends an M-sequence modulated ultrasonic signal to space.
  • a phase modulation method is used for ultrasonic modulation.
  • control circuit 101 instructs the reception trigger driving circuit 105 to generate a trigger pulse, and then supplies the reception trigger driving circuit 105 with initial condition data in which the above-described M-sequence initial conditions are encoded.
  • the reception trigger transmitter 106 is driven by the output of the reception trigger drive circuit 105, and sends a reception trigger signal from the electronic pen 10 to the space.
  • This reception trigger signal is transmitted as an infrared signal which is an electromagnetic wave signal, for example.
  • the M series is selected in the M series selection mode.
  • the control circuit 101 determines the M-sequence initial condition in order for each transmission period from among a plurality of initial conditions determined in the M-sequence selection mode based on the M-sequence characteristic polynomial. Then, this initial condition is transmitted to the M-sequence generation circuit 102 and the reception trigger drive circuit 105.
  • the M-sequence generation unit 102 generates M-sequence data according to this initial condition.
  • the ultrasonic drive circuit 103 supplies the M series data to the ultrasonic transmitter 104 as a drive signal for ultrasonic modulation.
  • the ultrasonic transmitter 104 modulates the ultrasonic wave using this drive signal as a modulation signal, and sends the M-sequence modulated ultrasonic signal to space.
  • FIG. 2 shows an example of a waveform of a modulated wave phase-modulated by the M sequence as an example of coding by the M sequence.
  • the waveform of an ultrasonic signal obtained by phase-modulating an ultrasonic wave having a constant frequency with a 15-bit M-sequence “100010011010111” is shown.
  • the waveform shown in FIG. 2 corresponds to one cycle of the fundamental wave per bit (for example, 40 kHz), and is “0” in phase inversion and “1” in phase modulation.
  • the wave has a length of 15 fundamental waves.
  • control circuit 101 instructs the reception trigger drive circuit 105 to generate a reception trigger signal, and then supplies the selected M-sequence initial condition data to the reception trigger drive circuit 105.
  • the reception trigger transmitter 106 is driven by the output of the reception trigger driving circuit 105 and sends a reception trigger signal from the electronic pen 10 to the space.
  • the receiving unit 200 of the receiving device 20 includes one or more ultrasonic receivers 201, one or more sampling circuits 202 corresponding to the ultrasonic receiver 201, a reception trigger receiver 203, and a detection circuit 204.
  • the reception trigger receiver 203 receives a reception trigger signal from the electronic pen 10 and converts the reception trigger signal into an electric signal.
  • the detection circuit 204 When detecting the reception trigger signal from the output of the reception trigger receiver 203, the detection circuit 204 stores the arrival time of the reception trigger signal in the memory 205, and then detects M-sequence initial condition data and stores it in the memory 205. To do.
  • the ultrasonic receiver 201 receives the ultrasonic signal transmitted from the electronic pen 10 and converts the ultrasonic signal into an electric signal of an M-sequence code.
  • the sampling circuit 202 samples the output of the ultrasonic receiver 201 at a constant sampling interval ( ⁇ T), and sequentially stores the sampled ultrasonic waveform data in the memory 205. Further, the sampling circuit 202 performs filter processing for the purpose of noise removal as necessary.
  • FIG. 3 shows an example of a waveform in which an ultrasonic wave phase-modulated by a 15-bit M-sequence data string “100010011010111” is received.
  • the received waveform of the ultrasonic wave stored in the memory 205 with the sampling interval ( ⁇ T) being 1/16 of the fundamental wave period of the ultrasonic wave is shown.
  • the horizontal axis indicates the time when the reception trigger signal is received as “0”.
  • the basic period of the ultrasonic wave is 50 ⁇ sec
  • the sampling interval is 3.125 ⁇ sec.
  • the ultrasonic reception waveform (FIG. 3) stored in the memory 205 is a synthesized wave in which a direct wave or a reflected wave of the transmitted ultrasonic wave and noise are mixed.
  • the data processing circuit 206 reads M-sequence initial condition data, and based on this initial condition (further characteristic polynomial if necessary), the M-sequence model A waveform is generated, and correlation processing is performed with the ultrasonic reception waveform stored in the memory 205.
  • the reception trigger signal and the ultrasonic signal are repeatedly sent from the electronic pen 10. At that time, a different M sequence is used for each transmission.
  • the data processing circuit 206 checks the degree of correlation of the ultrasonic wave with the M-sequence model waveform for each reception based on a plurality of secondary peaks generated when the shapes partially coincide with each other to check the optimum degree of the M-sequence. .
  • the optimality of the M series having a smaller maximum secondary peak value is evaluated higher.
  • the M series corresponding to the order of the largest secondary peak value is selected from all M series.
  • a reception trigger signal and an ultrasonic signal generated based on the selected M series are transmitted and correlation processing is performed.
  • the data processing circuit 206 detects the first peak of the correlation value, the elapsed time from the arrival time of the reception trigger signal to the time when the peak is detected, that is, the propagation time of the ultrasonic signal from the electronic pen 10 to the receiving unit 200. Is calculated.
  • control circuit 101 selects an arbitrary M sequence from a plurality of M sequences different from each other, and determines an initial condition of the selected M sequence (step 301).
  • the control circuit 101 supplies the determined initial condition to the M-sequence generation circuit 102 (step 302).
  • control circuit 101 determines the M-sequence initial condition
  • the control circuit 101 instructs the reception trigger drive circuit 105 to generate a trigger pulse, and supplies initial condition data in which the initial condition is encoded. (Step 303).
  • the M-sequence generation circuit 102 generates M-sequence data based on the initial conditions set by the control circuit 101 (step 304), and supplies it to the ultrasonic drive circuit 103.
  • the ultrasonic drive circuit 103 generates a drive signal (modulation signal) for modulating ultrasonic waves from the M-sequence data supplied from the M-sequence generation circuit 102 (step 305).
  • the reception trigger drive circuit 105 generates a reception trigger drive signal in response to a trigger pulse generation instruction from the control circuit 101 (step 306).
  • the reception trigger transmitter 106 and the ultrasonic transmitter 104 are simultaneously driven by the outputs of the reception trigger drive circuit 105 and the ultrasonic drive circuit 103, respectively.
  • the ultrasonic signal modulated by the M series is transmitted from the electronic pen 10 to the space (step 307).
  • step 307 the control circuit 101 determines whether or not all M-sequence initial conditions have been checked in determination step 308. If transmission of all M sequences has not been completed, the control circuit 101 returns to step 301 and sets initial conditions for the next M sequence.
  • steps 301 to 307 are sequentially executed until transmission of all M sequences is completed, and a plurality of ultrasonic signals modulated by different M sequences are sequentially transmitted.
  • a plurality of reception trigger signals modulated by the trigger condition and initial condition data that encodes these M-sequence initial conditions are sequentially transmitted.
  • the processing of steps 301 to 307 is repeated 15 times to check 15 types of M-sequence data.
  • the M sequence to be used is selected from all M sequences (step 309).
  • step 311 when the electronic pen 10 starts to operate (step 311), the control circuit 101 sequentially starts from the M-sequence initial conditions corresponding to the M-sequence selected in the M-sequence selection mode for each transmission cycle. One is determined (step 312), and the determined initial condition is supplied to the M-sequence generation circuit 102 (step 313).
  • control circuit 101 supplies a trigger pulse and M-sequence initial condition data to the reception trigger drive circuit 105 and instructs generation of a reception trigger signal (step 314).
  • the M-sequence generation circuit 102 generates M-sequence data based on the supplied initial conditions (Step 315), and supplies it to the ultrasonic drive circuit 103.
  • the ultrasonic drive circuit 103 generates a drive signal (modulation signal) for modulating the ultrasonic wave from the M-sequence data supplied from the M-sequence generation circuit 102 (step 316).
  • reception trigger drive circuit 105 generates a reception trigger drive signal (step 317).
  • the reception trigger transmitter 106 and the ultrasonic transmitter 104 are simultaneously driven by the outputs of the reception trigger drive circuit 105 and the ultrasonic drive circuit 103, respectively.
  • the ultrasonic signal modulated by the series is sent from the electronic pen 10 to the space (step 318).
  • step 318 the control circuit 101 drives a timer for determining the transmission cycle (step 319).
  • step 320 the control circuit 101 determines whether or not the operation of the electronic pen 10 has been completed (step 321). If the operation is in operation, the control circuit 101 returns to step 312. The initial condition of the M sequence is determined again at the start of the next transmission cycle, and the above operation is repeated.
  • control circuit 101 returns from step 321 to step 311.
  • the sampling circuit 202 samples the ultrasonic signal received by the ultrasonic receiver 201 at a constant sampling interval. Ultrasonic waveform data is stored in the memory 205.
  • the detection circuit 204 detects a trigger detection signal and M-sequence initial condition data from the reception trigger signal received by the reception trigger receiver 203, and stores it in the memory 205.
  • the data processing circuit 206 reads the trigger detection signal from the memory 205, and sets the value “t” (sampling time) of the sampling counter to “0” (step 401).
  • the M-sequence initial condition is set to the initial condition stored in the memory (step 402), and an M-sequence model waveform by phase modulation as shown in FIG. 2 is generated based on the initial condition (step 403). If the M sequence is being selected (step 404), the data processing circuit 206 sets the correlation start time (t s ) (step 405), and proceeds to the correlation value calculation step 406.
  • step 406 first, N received ultrasonic waveform data are read from the memory 205, and correlation calculation is performed with the model waveform generated in step 403, and the correlation value C is calculated based on the following equation (1). (T) is calculated and stored in the memory.
  • Equation 1 i is an integer value and the sampling time is a variable, N is the number of samplings of the model waveform, r (i) is the value of the model waveform at the sampling time i, and f (i + t) is the reception of the sampling time (i + t). The value of the waveform.
  • step 407 It is determined whether or not a predetermined time has elapsed since the start of the correlation process (step 407). If not, the sampling time t is advanced by the unit amount 1 in step 408, and the process returns to step 406. This correlation calculation is executed until a predetermined time elapses, and a plurality of correlation values are stored in the memory 205.
  • step 409 it is determined whether or not the M series is being selected. If the M series is being selected, the maximum correlation value (primary value) is selected from the correlation values stored in the memory 205. A peak) is detected, and the time of occurrence is set as the ultrasonic arrival time (t e ) (step 410).
  • step 411 the data processing circuit 206, based on the following equation (2), a period from the correlation start time to immediately before the ultrasonic wave arrival time, that is, The maximum correlation value at is detected.
  • P (n) is a period before the ultrasonic arrival time of an initial condition n of an M series ( ) Represents the maximum value of the correlation value C (t).
  • this period is a period in which the shape of the incoming ultrasonic wave partially matches the model waveform, and the correlation value that appears as a result is referred to as a secondary peak.
  • t s and t e are not limited and may be arbitrarily determined.
  • the detected maximum secondary peak is stored in the memory 205.
  • the ultrasonic data and all correlation values stored in the memory 205 are erased in step 412, and preparations are made for storing the next incoming ultrasonic data, trigger detection signal, and M-sequence initial condition data.
  • the data processing circuit 206 determines whether or not the selection of all M sequences has been completed (step 413), and if not completed, returns to step 401 to detect the arrival of the next reception trigger signal and ultrasonic signal.
  • the memory 205 is monitored and the trigger detection signal is read.
  • the data processing circuit 206 proceeds to step 414, and uses the M series corresponding to the secondary peak in ascending order of all secondary peaks stored in the memory 205. Select as the M series, end the M series selection mode, and return to step 401.
  • an M-sequence bit string is automatically determined by a preset characteristic polynomial. It is also possible to make an array shifted by 1 bit without changing the.
  • FIG. 7 shows the correlation value between the above-mentioned ultrasonic reception waveform and the 15-bit M-sequence model waveform of FIG. 2, and shows that the maximum secondary peak is detected at the point of the arrow in step 410.
  • FIG. 8 shows a correlation value when using a 15-bit M-sequence data string shifted by 1 bit in the 15-bit M-sequence of FIG. 2, that is, an ultrasonic wave phase-modulated by “000100110101111”, and the maximum secondary peak is an arrow. It is detected at the point.
  • FIG. 9 shows a correlation value when an ultrasonic wave phase-modulated by a 15-bit M-sequence data string “100110101111000” is used, and shows that the maximum secondary peak is detected at the point of the arrow.
  • the time when the trigger pulse is received is “0”, and the sampling interval is 3.125 ⁇ sec.
  • the correlation value peak (main peak) at the time of arrival of the ultrasonic wave appears at the same time.
  • the ultrasonic signal is attenuated by the propagation distance, it is necessary to set the necessary number of M series in consideration of how many cycles before the reception unit 200 may receive the ultrasonic signal.
  • a plurality of different codes are allocated corresponding to a plurality of different M sequences, and these codes and the corresponding M sequence initial conditions and characteristic polynomials are assigned. It is possible to provide the receiving unit 200 with an associated mapping table.
  • the transmitting unit 100 transmits a code (index) assigned to this M sequence by a reception trigger signal when transmitting one M sequence, and the receiving unit 200 receives the reference by referring to the mapping table.
  • the M-sequence initial condition and the characteristic polynomial associated with the code are read out.
  • This method can transmit the M-sequence initial condition and characteristic polynomial to the receiving side with a small amount of information.
  • Different M-sequence bit strings may be assigned corresponding to the mapping table.
  • the initial conditions of the M sequence determined as described above are set in the control circuit 101 of the transmission unit 100 and used in the ultrasonic propagation time measurement mode. Therefore, the transmission unit 100 cyclically changes the set plurality of M sequences for each transmission cycle, generates a reception trigger signal and an ultrasonic signal based on the M sequences, and sends them to the reception unit 200.
  • the data processing circuit 206 stores the trigger detection signal in the memory 205 in step 401.
  • the M-sequence initial condition is set to the initial condition stored in the memory, and an M-sequence model waveform is generated (step 403).
  • the data processing circuit 206 skips step 405 and proceeds to step 406 to read M-sequence ultrasonic data for one sample from the memory 205 as described above, and generate the M-sequence model generated in step 403. Correlation calculation with the waveform is executed, and a correlation value C (t) is calculated based on the equation (1) and stored in the memory 205.
  • the data processing circuit 206 executes step 406 until a predetermined time elapses, and proceeds from step 407 to step 409. In step 409, since the M-sequence selection mode has already been completed, the processing from step 415 is executed.
  • step 415 the data processing circuit 206 selects a correlation value greater than or equal to a predetermined value larger than the value of the secondary peak from all correlation values calculated within a predetermined time, and detects the top peak from the correlation value.
  • the sampling time (t f ) at the time when the first peak is detected is set as the first peak detection time (step 416), and the ultrasonic wave propagation time (t f ⁇ ⁇ T) is calculated (step 417).
  • step 418 all data is erased from the memory 205.
  • FIG. 10 is a diagram showing two-dimensionally the position calculation method between the electronic pen 10 and the ultrasonic receivers 201-1 and 201-2.
  • P is the position coordinate value (x, y) in the xy coordinates on the drawable range of the electronic pen
  • S1 and S2 are the positions of the ultrasonic receiving units 201-1 and 201-2, respectively. Yes.
  • D1 is the distance from the electronic pen 10 to the ultrasonic receiver 201-1 and d2 is the distance from the electronic pen 10 to the ultrasonic receiver 201-2.
  • D is the distance from the origin when the center of the ultrasonic receivers 201-1 and 201-2 is the origin of the xy coordinates.
  • ⁇ represents an angle formed by a straight line connecting the electronic pen 10 and the ultrasonic receiver 201-1 with the x-axis.
  • the ultrasonic propagation times calculated based on the ultrasonic signals received by the ultrasonic receivers 201-1 and 201-2 are t1 and t2, respectively, and the sound velocity is A.
  • FIG. 11 is a diagram for explaining the operation of the receiving unit 200 in the ultrasonic propagation time measurement mode.
  • the reflected wave of the previous period is also received in addition to the direct wave, but the reflected wave of the previous period and the M series of the current period can be obtained by using M-sequence ultrasonic waves having a small secondary peak. Even if the peak of the cross-correlation value with the model waveform overlaps with the secondary peak, the peak of the direct wave can be detected.
  • the M-sequence selection mode each time the reception device 20 receives the reception trigger signal and the ultrasonic signal, the correlation value between all the M-sequence model waveforms used for the ultrasonic signal is obtained. Check the cross-correlation value. At that time, M-sequence data with a smaller cross-correlation value peak value is evaluated higher, and the M-sequence (initial stage) that forms a combination of M-sequences with respect to the cross-correlation value from the smaller cross-correlation value peak of all M sequences Condition) may be assigned as the M sequence to be used.
  • a combination having a low cross-correlation value may be selected from the M sequences having a small secondary peak and assigned as the M sequence to be used.
  • the transmission unit 100 and the reception unit 200 can be realized by a hardware configuration similar to that of a general computer device.
  • Main components such as a CPU (Central Processing Unit) 401 and a RAM (Random Access Memory) are provided.
  • a main memory unit 402 used as a data work area and a temporary data save area, a communication unit 403 functioning as a transmitter and receiver of electromagnetic wave signals and ultrasonic signals, an input device 405, an output device 406, and a memory
  • An input / output interface unit 404 that is connected to the apparatus 407 and transmits / receives data, and a system bus 408 that connects the above components to each other are provided.
  • the storage device 407 is, for example, a ROM (Read Only Memory), a hard disk device including a non-volatile memory such as a magnetic disk and a semiconductor memory.
  • a circuit component which is a hardware component such as an LSI (Large Scale Integration) in which a position detection program for realizing the function of each unit shown in FIG.
  • LSI Large Scale Integration
  • the operation is realized in hardware, the position detection program is stored in the storage device 407, and the program is realized by loading the program into the main storage unit 402 and executing it by the CPU 401. It is also possible to do.
  • the present invention can be applied to a robot system.
  • the position of the robot in the space can be detected by installing the transmitter on the robot and installing the receiver on the ceiling or wall of a certain space. By grasping the position of the robot in space, the robot can be controlled and used for collision avoidance.
  • the transmitting device on a person or the like and installing the receiving device on the ceiling or wall of a certain space, it can be applied to applications such as detection of flow lines and position tracking in the space.
  • M sequence modulation by M sequence has been described, but it is not limited to M sequence as long as it is a pseudo-random signal having high autocorrelation and low cross-correlation with other sequences such as Gold sequence, for example. .

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  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
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  • General Physics & Mathematics (AREA)
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Abstract

The propagation time of a direct wave which reaches first from an ultrasonic transmitting source without being affected by a reflected wave is allowed to be accurately calculated.  A plurality of ultrasonic signals generated on the basis of a plurality of M sequences different from one another are transmitted from the transmitting side to the receiving side.   The receiving side executes correlation processing between each of the model waveforms of the M sequences and the waveform of each of the ultrasonic signals, detects the secondary peak of the correlation value appearing when the both waveforms are partially matched, and determines corresponding M sequences out of the M sequences of smaller secondary peaks detected in all the correlation processings.  The transmitting side selects M sequences different in each transmission period out of the determined M sequences, and sends out an ultrasonic signal and an electromagnetic wave signal modulated by the selected M sequence to the receiving side.  The receiving side calculates the correlation value between the ultrasonic signal and the model waveform, detects the first main peak of the calculated correlation value, and calculates the propagation time of the ultrasonic wave from the point at which the electromagnetic wave signal is received and the point at which the main peak is detected.

Description

位置検出システム、送信装置、受信装置、位置検出方法、位置検出プログラムPosition detection system, transmission device, reception device, position detection method, position detection program
　本発明は、超音波信号を用いて移動体の位置を決定する位置決定システムに関し、特に、超音波を用いて移動体の位置を正確かつ安定的に決定することを可能にする位置検出システム、送信装置、受信装置、位置検出方法、位置検出プログラムに関する。 The present invention relates to a position determination system that determines the position of a moving body using ultrasonic signals, and in particular, a position detection system that makes it possible to accurately and stably determine the position of a moving body using ultrasonic waves, The present invention relates to a transmission device, a reception device, a position detection method, and a position detection program.
　超音波の伝搬時間により距離計測を行う装置の関連技術の一例として、超音波物体計測装置が特許文献１に記載されている。この特許文献１に記載の超音波物体計測装置は、トーンバースト波発生器から発生するトーンバースト波に、周波数拡散変調器で疑似雑音信号発生器からの疑似雑音信号によって周波数拡散変調を施して送信する。 Patent Document 1 discloses an ultrasonic object measuring apparatus as an example of a related technique of an apparatus that measures distance based on ultrasonic propagation time. The ultrasonic object measuring apparatus described in Patent Document 1 performs transmission by performing frequency spread modulation on a tone burst wave generated from a tone burst wave generator using a pseudo noise signal from a pseudo noise signal generator by a frequency spread modulator. To do.
　反射波を受信して周波数拡散信号復調器で復調した信号と、周波数拡散を行う場合に用いた疑似雑音信号との相互相関を相互相関器で得る。さらに相関度合検出器９で得られる相関度合から、物体での反射信号の受信の有無を判定し、さらに距離を計測する。 The cross-correlator obtains the cross-correlation between the signal received by the reflected wave and demodulated by the frequency spread signal demodulator and the pseudo noise signal used for frequency spreading. Further, from the correlation level obtained by the correlation level detector 9, the presence or absence of reception of the reflected signal at the object is determined, and the distance is further measured.
　また、複数の疑似雑音信号を順次切り替えて区別した周波数拡散変調信号を用いて送信トーンバースト波を送出し、複数のトーンバースト波を区別判別する。 Also, a transmission tone burst wave is transmitted using a frequency spread modulation signal obtained by sequentially switching a plurality of pseudo-noise signals, and the plurality of tone burst waves are distinguished and discriminated.
特開平７－１０４０６３号公報Japanese Patent Application Laid-Open No. 7-104063
　超音波発信源から送信される超音波信号は、人に聞こえない可聴帯域以上の周波数が用いられるため、少なくとも２０ｋＨｚ以上であることが必要である。この周波数帯域の信号を十分な音圧で発生させる手段としては、小型高剛性の振動板を電磁的に振動駆動する、いわゆるスピーカーが知られている。しかしながら、小型化が困難なこと、電流駆動であるため消費電力が大きいことなどから小型の移動体に実装することは困難である。そのため、超音波発信源として電圧駆動である圧電素子が広く用いられている。 Since the ultrasonic signal transmitted from the ultrasonic transmission source uses a frequency that is higher than the audible band that cannot be heard by humans, it must be at least 20 kHz or higher. As a means for generating a signal in this frequency band with a sufficient sound pressure, a so-called speaker is known which electromagnetically drives a small and highly rigid diaphragm. However, it is difficult to mount on a small mobile body because it is difficult to reduce the size and power consumption is large because of current driving. For this reason, voltage-driven piezoelectric elements are widely used as ultrasonic transmission sources.
　この圧電素子は、電圧駆動型であるため一般的に消費電力が小さいが、十分な音圧を確保するためには音響インピーダンスの低い共振体と組み合わせて用いられることが多い。しかしながら、共振現象を利用した場合、一定の位相・周波数・ゲインで超音波を発信できるが、それ以外の周波数での送信ゲインはかなり低く、周波数拡散変調といった広帯域の周波数特性を有する変調方式を利用することが困難である。 Since this piezoelectric element is a voltage driven type, it generally consumes less power, but in order to ensure sufficient sound pressure, it is often used in combination with a resonator with low acoustic impedance. However, when the resonance phenomenon is used, ultrasonic waves can be transmitted with a constant phase, frequency, and gain, but the transmission gain at other frequencies is considerably low, and a modulation method having wideband frequency characteristics such as frequency spread modulation is used. Difficult to do.
　また、単独の圧電素子においても機械的なＱが高く残留振動が長引くため、変調方式の如何を問わず変調波に正確に追従した超音波を発信することが困難である。 Also, since a single piezoelectric element has a high mechanical Q and a long residual vibration, it is difficult to transmit an ultrasonic wave that accurately follows the modulated wave regardless of the modulation method.
　このような超音波の送信機に残留振動が多い送信源を用いた場合、もしくは周波数拡散変調された超音波の送受信に必要な周波数帯域に比べ送信源の帯域が不足する場合に、理想的な変調波を送信することが難しいため、非疑似雑音のため生じる副次的な相関ピークを抑制することが難しいという問題点がある。 This is ideal when a transmitter with a lot of residual vibration is used for such an ultrasonic transmitter, or when the bandwidth of the transmitter is insufficient compared to the frequency band required for transmission / reception of frequency-spread modulated ultrasonic waves. Since it is difficult to transmit a modulated wave, there is a problem that it is difficult to suppress a secondary correlation peak caused by non-pseudo noise.
（発明の目的）
　本発明の目的は、送信機から送出される超音波を、受信機で受信しその超音波の伝搬時間を測定し、送受信機間の距離もしくは送信機の位置を検出するシステムにおいて、各測定周期で、それ以前に周期に送信された超音波の反射波の影響を低減し、最も先に到達する直接波の伝搬時間を正確に測定することができる位置検出システム、送信装置、受信装置、位置検出方法、位置検出プログラムを提供することにある。 (Object of invention)
It is an object of the present invention to receive an ultrasonic wave transmitted from a transmitter at a receiver, measure the propagation time of the ultrasonic wave, and detect the distance between the transmitter and the transmitter or the position of the transmitter in each measurement cycle. The position detection system, transmitter, receiver, position that can reduce the influence of the reflected wave of the ultrasonic wave transmitted in the previous period and accurately measure the propagation time of the direct wave that reaches the earliest The object is to provide a detection method and a position detection program.
　本発明による位置検出システムは、自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を送出する送信部を含む移動体と、超音波信号を受信し、擬似ランダム信号と同じ擬似ランダム信号により変調された超音波のモデル波形を生成し、受信した超音波信号との間で相関値を求め、該超音波信号が該擬似ランダム信号モデル波形と部分的に一致したときに現れる相関値の副次ピークが小さいほうから対応する擬似ランダム信号を複数選択する受信部とを含み、送信部は、電磁波信号と、選択された擬似ランダム信号に基づき変調された超音波信号とを同時に送出する手段を含み、受信部は、該超音波信号と擬似ランダム信号により変調された超音波モデル波形との間で相関処理を実行することにより超音波信号の到達時間を特定し、電磁波信号の到着時点と特定された到達時間とから超音波の伝搬時間を算出する手段と、算出した超音波伝播時間と超音波受信手段相互の間隔長に基づいて、移動体の位置を算出する手段とを含み、送信部は、送信周期毎に異なる擬似ランダム信号を使用する。 A position detection system according to the present invention includes a moving body including a transmission unit that transmits an ultrasonic signal modulated based on a pseudorandom signal with high autocorrelation, and a pseudorandom signal that receives the ultrasonic signal and is the same as the pseudorandom signal. A model waveform of the ultrasonic wave modulated by the above is generated, a correlation value is obtained with the received ultrasonic signal, and a correlation value that appears when the ultrasonic signal partially matches the pseudo-random signal model waveform A receiving unit that selects a plurality of corresponding pseudo-random signals from the smaller secondary peak, and the transmitting unit simultaneously transmits an electromagnetic wave signal and an ultrasonic signal modulated based on the selected pseudo-random signal. And the reception unit calculates the arrival time of the ultrasonic signal by executing a correlation process between the ultrasonic signal and the ultrasonic model waveform modulated by the pseudo-random signal. The position of the moving body based on the calculated ultrasonic propagation time from the arrival time of the electromagnetic wave signal and the identified arrival time, and the distance between the calculated ultrasonic propagation time and the ultrasonic receiving means. And a transmission unit uses a pseudo-random signal that is different for each transmission cycle.
　本発明による送信装置は、送信装置から送信される超音波信号を受信装置で受信して送信装置の位置を検出する位置検出システムの送信装置であって、自己相関性の高い擬似ランダム信号に基づき変調された第１の超音波信号を送出する手段と、送信タイミングを表す電磁波信号と、受信装置で選択された擬似ランダム信号に基づき変調された第２の超音波信号とを同時に送出する手段を含み、送信周期毎に異なる擬似ランダム信号を使用する。 A transmission device according to the present invention is a transmission device of a position detection system that receives an ultrasonic signal transmitted from a transmission device by a reception device and detects the position of the transmission device, and is based on a pseudo-random signal having high autocorrelation. Means for transmitting the modulated first ultrasonic signal, means for simultaneously transmitting the electromagnetic wave signal indicating the transmission timing, and the second ultrasonic signal modulated based on the pseudo-random signal selected by the receiver. Including a different pseudo-random signal for each transmission cycle.
　本発明による受信装置は、送信装置から送信される超音波信号を受信装置で受信し送信装置の位置を検出する位置検出システムの受信装置であって、送信装置から送信される自己相関性の高い擬似ランダム系列のデータにより変調された第１の超音波信号を受信し、擬似ランダム信号と同じ擬似ランダム信号により変調された超音波のモデル波形を生成し、受信した超音波信号との間で相関値を求め、該超音波信号が該擬似ランダム信号モデル波形と部分的に一致したときに現れる相関値の副次ピークが小さいほうから対応する擬似ランダム信号を複数選択する手段と、送信装置から同時に送出される電磁波信号と、受信装置で選択した擬似ランダム信号に基づき変調された第２の超音波信号を受信し、該第２の超音波信号と擬似ランダム信号により変調された超音波モデル波形との間で相関処理を実行することにより超音波信号の到達時間を特定し、電磁波信号の到着時点と特定された到達時間とから超音波の伝搬時間を算出する手段と、算出した超音波伝播時間と超音波受信手段相互の間隔長に基づいて、移動体の位置を算出する手段とを含む。 A receiving device according to the present invention is a receiving device of a position detection system that receives an ultrasonic signal transmitted from a transmitting device and detects the position of the transmitting device, and has high autocorrelation transmitted from the transmitting device. The first ultrasonic signal modulated by the pseudo-random sequence data is received, the model waveform of the ultrasonic wave modulated by the same pseudo-random signal as the pseudo-random signal is generated, and the correlation with the received ultrasonic signal is generated. Means for selecting a plurality of corresponding pseudo-random signals from the smaller secondary peak of the correlation value that appears when the ultrasonic signal partially matches the pseudo-random signal model waveform; A second ultrasonic signal modulated based on the electromagnetic wave signal to be transmitted and the pseudo random signal selected by the receiving device is received, and the second ultrasonic signal and the pseudo random signal are received. The arrival time of the ultrasonic signal is specified by executing correlation processing with the ultrasonic model waveform modulated by the signal, and the propagation time of the ultrasonic wave is calculated from the arrival time of the electromagnetic wave signal and the specified arrival time And means for calculating the position of the moving body based on the calculated ultrasonic propagation time and the interval length between the ultrasonic receiving means.
　本発明による位置検出方法は、ａ）自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を移動体の送信部から送出するステップと、ｂ）受信部で超音波信号を受信し、擬似ランダム信号により変調された超音波のモデル波形を生成し、該モデル波形と受信した超音波信号との間で相関処理を実行し相関波形を検出するステップと、ｃ）異なる擬似ランダム信号について、相関波形を複数検出し、モデル波形と受信超音波信号とが部分的に一致した際に各相関波形に現れる副次ピークが小さいほうから対応する擬似ランダム信号を複数選択するステップと、ｄ）ステップ（ｃ）で選択された擬似ランダム信号に基づき変調された超音波信号と、送信タイミングを表すトリガ信号と該擬似ランダム信号を規定するデータを含む電磁波信号とを一定送信周期毎に同時に移動体から送出するステップと、ｅ）該電磁波信号を受信し該電磁波信号が含む擬似ランダム信号を規定するデータから擬似ランダム信号により変調された超音波モデル波形を生成するステップと、ｆ）超音波信号を受信し、受信した超音波信号とステップ（ｅ）で生成された超音波モデル波形との間で相関値を算出するステップと、ｇ）算出した超音波伝播時間と超音波受信手段相互の間隔長に基づいて、移動体の位置を算出するステップとを含み、ステップ（ｄ）は送信周期毎に異なる擬似ランダム信号を使用する。 In the position detection method according to the present invention, a) a step of transmitting an ultrasonic signal modulated based on a pseudorandom signal having a high autocorrelation from a transmission unit of a moving body, and b) a reception unit receiving the ultrasonic signal, Generating a model waveform of an ultrasonic wave modulated by a pseudo-random signal, executing correlation processing between the model waveform and the received ultrasonic signal, and detecting a correlation waveform; c) for different pseudo-random signals, A step of detecting a plurality of correlation waveforms, and selecting a plurality of corresponding pseudo-random signals from the smaller secondary peak appearing in each correlation waveform when the model waveform and the received ultrasonic signal partially match, and d) step An ultrasonic signal modulated based on the pseudo-random signal selected in (c), a trigger signal indicating transmission timing, and an electric signal including data defining the pseudo-random signal. A step of simultaneously transmitting a wave signal from a moving body at a predetermined transmission period; e) an ultrasonic model waveform modulated by a pseudo random signal from data defining the pseudo random signal included in the electromagnetic wave signal after receiving the electromagnetic wave signal; F) receiving an ultrasonic signal, calculating a correlation value between the received ultrasonic signal and the ultrasonic model waveform generated in step (e), and g) calculating the calculated ultrasonic Calculating the position of the moving body based on the sound wave propagation time and the interval length between the ultrasonic wave receiving means, and step (d) uses a pseudo-random signal that is different for each transmission period.
　本発明による位置検出プログラムは、移動体に備えられた送信装置を構成するコンピュータに、自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を移動体の送信部から送出する処理を実行させ、受信装置を構成をするコンピュータに、超音波信号を受信し、擬似ランダム信号により変調された超音波のモデル波形を生成し、該モデル波形と受信した超音波信号との間で相関処理を実行し相関波形を検出する処理と、異なる擬似ランダム信号について、相関波形を複数検出し、モデル波形と受信超音波信号とが部分的に一致した際に各相関波形に現れる副次ピークが小さいほうから対応する擬似ランダム信号を複数選択する処理とを実行させ、送信装置を構成するコンピュータに、選択された擬似ランダム信号に基づき変調された超音波信号と、送信タイミングを表すトリガ信号と該擬似ランダム信号を規定するデータを含む電磁波信号とを一定送信周期毎に同時に移動体から送出する処理を実行させ、受信装置を構成をするコンピュータに、該電磁波信号を受信し該電磁波信号が含む擬似ランダム信号を規定するデータから擬似ランダム信号により変調された超音波モデル波形を生成する処理と、超音波信号を受信し、受信した超音波信号と生成された超音波モデル波形との間で相関値を算出する処理と、算出した超音波伝播時間と超音波受信手段相互の間隔長に基づいて、移動体の位置を算出する処理を実行させ、送信装置からの超音波信号の送出において、送信周期毎に異なる擬似ランダム信号を使用する。 The position detection program according to the present invention executes a process of transmitting an ultrasonic signal modulated based on a pseudo-random signal having high autocorrelation from a transmission unit of a mobile body to a computer constituting a transmission device provided in the mobile body. Then, the computer constituting the receiving apparatus receives the ultrasonic signal, generates an ultrasonic model waveform modulated by the pseudo-random signal, and performs correlation processing between the model waveform and the received ultrasonic signal. When the correlation waveform is detected and multiple correlation waveforms are detected for different pseudo-random signals and the model waveform and the received ultrasound signal partially match, the secondary peak that appears in each correlation waveform is smaller And processing for selecting a plurality of corresponding pseudo-random signals from the computer, and modulating the computer constituting the transmission device based on the selected pseudo-random signals The receiving apparatus is configured to execute a process of simultaneously transmitting the ultrasonic signal, the trigger signal indicating the transmission timing, and the electromagnetic wave signal including the data defining the pseudo-random signal from the moving body at a constant transmission period. Processing for generating an ultrasonic model waveform modulated by a pseudo-random signal from data defining the pseudo-random signal included in the electromagnetic wave signal, and receiving the ultrasonic signal and receiving the ultrasonic signal in a computer Processing to calculate correlation value between signal and generated ultrasonic model waveform, and processing to calculate position of moving object based on calculated ultrasonic propagation time and interval length between ultrasonic receiving means In the transmission of the ultrasonic signal from the transmission device, a different pseudo random signal is used for each transmission cycle.
　本発明によれば、超音波信号の反射波の影響を受けることなく、超音波発信源から最も先に到達する直接波の伝搬時間を正確に算出することが可能となる。 According to the present invention, it is possible to accurately calculate the propagation time of the direct wave that reaches the earliest from the ultrasonic wave transmission source without being affected by the reflected wave of the ultrasonic signal.
本発明の第１の実施の形態による位置検出システムの送信部と受信部の構成を示すブロック図である。It is a block diagram which shows the structure of the transmission part of the position detection system by the 1st Embodiment of this invention, and a receiving part. １ビット当たり１周期を割り当てた位相変調により変調された超音波Ｍ系列データの例を示す図である。It is a figure which shows the example of the ultrasonic M series data modulated by the phase modulation which allocated 1 period per bit. 本発明の第１の実施の形態による位置検出システムの受信部のメモリに格納される受信超音波波形の例を示す図である。It is a figure which shows the example of the received ultrasound waveform stored in the memory of the receiving part of the position detection system by the 1st Embodiment of this invention. 本発明の第１の実施の形態による位置検出システムにおけるＭ系列選択モードの送信部の動作を示すフローチャートである。It is a flowchart which shows operation | movement of the transmission part of the M sequence selection mode in the position detection system by the 1st Embodiment of this invention. 超音波伝搬測定モードの送信部の動作を示すフローチャートである。It is a flowchart which shows operation | movement of the transmission part in ultrasonic propagation measurement mode. 本発明の第１の実施の形態による位置検出システムにおける受信部の動作を示すフローチャートである。It is a flowchart which shows operation | movement of the receiving part in the position detection system by the 1st Embodiment of this invention. Ｍ系列選択モードにおいてＭ系列が「１０００１００１１０１０１１１」の場合の相関値波形を示す図である。It is a figure which shows a correlation value waveform in case M series is "100010011010111" in M series selection mode. Ｍ系列選択モードにおいてＭ系列が「０００１００１１０１０１１１１」の場合の相関値波形を示す図である。It is a figure which shows a correlation value waveform in case M series is "000100110101111" in M series selection mode. Ｍ系列選択モードにおいてＭ系列が「１００１１０１０１１１１０００」の場合の相関値波形を示す図である。It is a figure which shows a correlation value waveform in case M series is "100110101111000" in M series selection mode. 本発明の第１の実施の形態による位置検出システムにおける電子ペンの位置算出方法を２次元で説明する図である。It is a figure explaining the position calculation method of the electronic pen in the position detection system by the 1st Embodiment of this invention in two dimensions. 本発明の第１の実施の形態による位置検出システムにおける超音波伝搬時間測定モードにおける受信部２００の動作を示す図である。It is a figure which shows operation | movement of the receiving part 200 in the ultrasonic propagation time measurement mode in the position detection system by the 1st Embodiment of this invention. 本発明の第１の実施の形態による位置検出システムにおける送信部と受信部のハードウェア構成例を示す図である。It is a figure which shows the hardware structural example of the transmission part and receiving part in the position detection system by the 1st Embodiment of this invention.
　次に、本発明による第１の実施の形態について図１乃至図１１を参照して詳細に説明する。
（第１の実施の形態）
　図１は、本発明の第１の実施の形態による位置検出システムの構成を示すブロック図である。以下の実施の形態においては、本発明による位置検出システムを、電子ペンシステムに適用した場合を説明する。 Next, a first embodiment according to the present invention will be described in detail with reference to FIGS.
(First embodiment)
FIG. 1 is a block diagram showing a configuration of a position detection system according to a first embodiment of the present invention. In the following embodiments, a case where the position detection system according to the present invention is applied to an electronic pen system will be described.
　図１において、本発明の第１の実施の形態による超音波伝搬時間測定を用いる位置検出システムは、送信部１００を装着する可動物体としての電子ペン１０と、電子ペン１０から離れた所定の位置に設置された受信部２００を備える受信装置２０を備えている。本位置検出システムでは、超音波伝搬時間の測定に先立ち使用するＭ系列の選択（以下、Ｍ系列選択モード）を行う。 In FIG. 1, a position detection system using ultrasonic propagation time measurement according to the first embodiment of the present invention includes an electronic pen 10 as a movable object on which a transmitter 100 is mounted, and a predetermined position away from the electronic pen 10. A receiving device 20 including a receiving unit 200 installed in the device is provided. In this position detection system, selection of an M sequence to be used prior to measurement of ultrasonic propagation time (hereinafter referred to as an M sequence selection mode) is performed.
　電子ペン１０の送信部１００は、制御回路１０１、Ｍ系列生成回路１０２、超音波駆動回路１０３、超音波送信機１０４、受信トリガ駆動回路１０５、受信トリガ送信機１０６とを備えている。 The transmission unit 100 of the electronic pen 10 includes a control circuit 101, an M-sequence generation circuit 102, an ultrasonic drive circuit 103, an ultrasonic transmitter 104, a reception trigger drive circuit 105, and a reception trigger transmitter 106.
　Ｍ系列生成回路１０２が生成するＭ系列は特性多項式により生成される系列であり、特性多項式と初期条件を規定することにより得られる。なお、Ｍ系列の詳細は、例えば、非特許文献１（柏木濶著「Ｍ系列とその応用」（１９９６年３月２５日，昭晃堂））に記述されている。例えば、４次の特性多項式f(x) = x4 + x + 1により生成される系列長が１５ビットであるデータ列を用いる。初期条件を変更することにより、データの並びが巡回的にシフトした１５通りの異なるデータ列が得られる。 The M series generated by the M series generation circuit 102 is a series generated by a characteristic polynomial, and is obtained by defining the characteristic polynomial and initial conditions. Details of the M series are described, for example, in Non-Patent Document 1 (Maki Satoshi, “M series and its application” (March 25, 1996, Shogodo)). For example, a data string having a sequence length of 15 bits generated by a fourth-order characteristic polynomial f (x) = x 4 + x + 1 is used. By changing the initial conditions, 15 different data strings in which the data sequence is cyclically shifted can be obtained.
　Ｍ系列選択モードにおいて、制御回路１０１は、予め各送信周期で決められた特性多項式に基づきＭ系列の初期条件を決定し、この初期条件を一定の送信周期でＭ系列生成回路１０２と受信トリガ駆動回路１０５に伝達する。 In the M-sequence selection mode, the control circuit 101 determines an M-sequence initial condition based on a characteristic polynomial determined in advance in each transmission cycle, and this initial condition is driven by the M-sequence generation circuit 102 and the reception trigger in a fixed transmission cycle. This is transmitted to the circuit 105.
　Ｍ系列生成手段１０２は、制御回路１０１から送られた初期条件に従って送信周期毎に異なるＭ系列のコード化されたビット列を生成する。 The M-sequence generation unit 102 generates an M-sequence coded bit string that is different for each transmission cycle in accordance with the initial condition sent from the control circuit 101.
　超音波駆動回路１０３は、Ｍ系列生成手段１０２で生成したこのＭ系列データを超音波変調用の駆動信号として超音波送信機１０４に供給する。 The ultrasonic drive circuit 103 supplies the M series data generated by the M series generation means 102 to the ultrasonic transmitter 104 as a drive signal for ultrasonic modulation.
　超音波送信機１０４は、超音波駆動回路１０３からの駆動信号を変調信号として超音波を変調しＭ系列変調された超音波信号を空間に送出する。好ましい実施例としては、超音波の変調に位相変調方式が使用される。 The ultrasonic transmitter 104 modulates an ultrasonic wave using the drive signal from the ultrasonic drive circuit 103 as a modulation signal, and sends an M-sequence modulated ultrasonic signal to space. In a preferred embodiment, a phase modulation method is used for ultrasonic modulation.
　一方、制御回路１０１は、トリガパルスの生成を受信トリガ駆動回路１０５に指示し、続いて上述のＭ系列の初期条件をコード化した初期条件データを受信トリガ駆動回路１０５に供給する。 On the other hand, the control circuit 101 instructs the reception trigger driving circuit 105 to generate a trigger pulse, and then supplies the reception trigger driving circuit 105 with initial condition data in which the above-described M-sequence initial conditions are encoded.
　超音波送信機１０４の送信タイミングに同期して、受信トリガ送信機１０６は、この受信トリガ駆動回路１０５の出力により駆動され、受信トリガ信号を電子ペン１０から空間に送出する。この受信トリガ信号は、例えば電磁波信号である赤外線信号として送出する。 In synchronization with the transmission timing of the ultrasonic transmitter 104, the reception trigger transmitter 106 is driven by the output of the reception trigger drive circuit 105, and sends a reception trigger signal from the electronic pen 10 to the space. This reception trigger signal is transmitted as an infrared signal which is an electromagnetic wave signal, for example.
　後述の如くＭ系列選択モードにおいてはＭ系列が選択される。続く超音波伝搬時間測定モードにおいて、制御回路１０１は、Ｍ系列の特性多項式に基づきＭ系列選択モードにより決定された複数の初期条件の中から、送信周期毎に順番にＭ系列の初期条件を決定し、この初期条件をＭ系列生成回路１０２と受信トリガ駆動回路１０５に伝達する。 As will be described later, the M series is selected in the M series selection mode. In the subsequent ultrasonic propagation time measurement mode, the control circuit 101 determines the M-sequence initial condition in order for each transmission period from among a plurality of initial conditions determined in the M-sequence selection mode based on the M-sequence characteristic polynomial. Then, this initial condition is transmitted to the M-sequence generation circuit 102 and the reception trigger drive circuit 105.
　Ｍ系列生成手段１０２は、この初期条件に従いＭ系列データを生成する。超音波駆動回路１０３は、このＭ系列データを超音波変調用の駆動信号として超音波送信機１０４に供給する。超音波送信機１０４は、この駆動信号を変調信号として超音波を変調しＭ系列変調された超音波信号を空間に送出する。 The M-sequence generation unit 102 generates M-sequence data according to this initial condition. The ultrasonic drive circuit 103 supplies the M series data to the ultrasonic transmitter 104 as a drive signal for ultrasonic modulation. The ultrasonic transmitter 104 modulates the ultrasonic wave using this drive signal as a modulation signal, and sends the M-sequence modulated ultrasonic signal to space.
　図２に、Ｍ系列によりコード化した一例として、Ｍ系列により位相変調された変調波の波形の例を示す。ここでは、一定の周波数の超音波を１５ビットのＭ系列「１０００１００１１０１０１１１」で位相変調された超音波信号の波形を示している。図２に示す波形は、１ビット当たり基本波（例えば４０ｋＨｚ）の１周期を対応させて、「０」の場合は反転位相で、「１」の場合は同相で位相変調したものであり、変調波は基本波１５周期分の長さとなっている。 FIG. 2 shows an example of a waveform of a modulated wave phase-modulated by the M sequence as an example of coding by the M sequence. Here, the waveform of an ultrasonic signal obtained by phase-modulating an ultrasonic wave having a constant frequency with a 15-bit M-sequence “100010011010111” is shown. The waveform shown in FIG. 2 corresponds to one cycle of the fundamental wave per bit (for example, 40 kHz), and is “0” in phase inversion and “1” in phase modulation. The wave has a length of 15 fundamental waves.
　一方、制御回路１０１は、受信トリガ信号の生成を受信トリガ駆動回路１０５に指示し、続いて選択したＭ系列の初期条件データを受信トリガ駆動回路１０５に供給する。 On the other hand, the control circuit 101 instructs the reception trigger drive circuit 105 to generate a reception trigger signal, and then supplies the selected M-sequence initial condition data to the reception trigger drive circuit 105.
　超音波送信機１０４の送信タイミングに同期して、受信トリガ送信機１０６は、この受信トリガ駆動回路１０５の出力により駆動され受信トリガ信号を電子ペン１０から空間に送出する。 In synchronization with the transmission timing of the ultrasonic transmitter 104, the reception trigger transmitter 106 is driven by the output of the reception trigger driving circuit 105 and sends a reception trigger signal from the electronic pen 10 to the space.
　受信装置２０の受信部２００は、１つないし複数の超音波受信機２０１と、超音波受信機２０１と対応する１つないし複数のサンプリング回路２０２と、受信トリガ受信機２０３と、検出回路２０４と、メモリ２０５及びデータ処理回路２０６とを備えている。 The receiving unit 200 of the receiving device 20 includes one or more ultrasonic receivers 201, one or more sampling circuits 202 corresponding to the ultrasonic receiver 201, a reception trigger receiver 203, and a detection circuit 204. A memory 205 and a data processing circuit 206.
　受信トリガ受信機２０３は、電子ペン１０からの受信トリガ信号を受信し、この受信トリガ信号を電気信号に変換する。 The reception trigger receiver 203 receives a reception trigger signal from the electronic pen 10 and converts the reception trigger signal into an electric signal.
　検出回路２０４は、受信トリガ受信機２０３の出力から受信トリガ信号を検出すると、受信トリガ信号の到来時刻をメモリ２０５に格納し、次にＭ系列の初期条件データを検出しこれをメモリ２０５に格納する。 When detecting the reception trigger signal from the output of the reception trigger receiver 203, the detection circuit 204 stores the arrival time of the reception trigger signal in the memory 205, and then detects M-sequence initial condition data and stores it in the memory 205. To do.
　超音波受信機２０１は、電子ペン１０から送信された超音波信号を受信し、この超音波信号をＭ系列コードの電気信号に変換する。 The ultrasonic receiver 201 receives the ultrasonic signal transmitted from the electronic pen 10 and converts the ultrasonic signal into an electric signal of an M-sequence code.
　サンプリング回路２０２は、超音波受信機２０１の出力を一定のサンプリング間隔（ΔＴ）でサンプル化し、サンプル化された超音波の波形データを順次メモリ２０５に格納する。また、サンプリング回路２０２では、必要に応じて、ノイズ除去を目的にフィルタ処理を行う。 The sampling circuit 202 samples the output of the ultrasonic receiver 201 at a constant sampling interval (ΔT), and sequentially stores the sampled ultrasonic waveform data in the memory 205. Further, the sampling circuit 202 performs filter processing for the purpose of noise removal as necessary.
　図３は、１５ビットＭ系列のデータ列「１０００１００１１０１０１１１」により位相変調された超音波を受信した波形の例を示している。ここでは、サンプリング間隔（ΔＴ）を超音波の基本波周期の１／１６としてメモリ２０５に格納された超音波の受信波形を示している。横軸は、受信トリガ信号を受信した時点を「０」とした時刻を示している。基本波の周波数が２０ｋＨｚの超音波を使用した場合、超音波の基本周期は５０μｓｅｃとなり、サンプリング間隔は３．１２５μｓｅｃとなる。メモリ２０５に格納された超音波の受信波形（図３）は、送信された超音波の直接波や反射波、さらにノイズが混合した合成波となる。 FIG. 3 shows an example of a waveform in which an ultrasonic wave phase-modulated by a 15-bit M-sequence data string “100010011010111” is received. Here, the received waveform of the ultrasonic wave stored in the memory 205 with the sampling interval (ΔT) being 1/16 of the fundamental wave period of the ultrasonic wave is shown. The horizontal axis indicates the time when the reception trigger signal is received as “0”. When an ultrasonic wave having a fundamental frequency of 20 kHz is used, the basic period of the ultrasonic wave is 50 μsec, and the sampling interval is 3.125 μsec. The ultrasonic reception waveform (FIG. 3) stored in the memory 205 is a synthesized wave in which a direct wave or a reflected wave of the transmitted ultrasonic wave and noise are mixed.
　データ処理回路２０６は、メモリ２０５に受信トリガ信号の到来時刻を示すデータが格納されると、Ｍ系列の初期条件データを読み出し、この初期条件（必要に応じて更に特性多項式）に基づきＭ系列モデル波形を生成し、メモリ２０５に格納されている超音波受信波形との間で相関処理を行う。 When the data indicating the arrival time of the reception trigger signal is stored in the memory 205, the data processing circuit 206 reads M-sequence initial condition data, and based on this initial condition (further characteristic polynomial if necessary), the M-sequence model A waveform is generated, and correlation processing is performed with the ultrasonic reception waveform stored in the memory 205.
　Ｍ系列選択モードの時、受信トリガ信号と超音波信号が繰り返し電子ペン１０から送出される。その際、送信毎に異なるＭ系列が使用される。データ処理回路２０６は、受信毎に超音波のＭ系列モデル波形との相関度を両者の形状が部分的に一致したとき生ずる複数の副次ピークに基づいて使用したＭ系列の最適度をチェックする。最大副次ピークの値が小さいＭ系列ほどの最適度が高く評価される。全Ｍ系列のうち最大副次ピークの値が小さい順に対応するＭ系列を選択する。 In the M-sequence selection mode, the reception trigger signal and the ultrasonic signal are repeatedly sent from the electronic pen 10. At that time, a different M sequence is used for each transmission. The data processing circuit 206 checks the degree of correlation of the ultrasonic wave with the M-sequence model waveform for each reception based on a plurality of secondary peaks generated when the shapes partially coincide with each other to check the optimum degree of the M-sequence. . The optimality of the M series having a smaller maximum secondary peak value is evaluated higher. The M series corresponding to the order of the largest secondary peak value is selected from all M series.
　超音波伝搬測定モードの時、選択されたＭ系列に基づき生成された受信トリガ信号と超音波信号が送出され相関処理が行われる。データ処理回路２０６は、相関値の最初のピークを検出すると受信トリガ信号の到来時刻からこのピークを検出した時点までの経過時間、即ち電子ペン１０からの受信部２００に至る超音波信号の伝搬時間を算出する。 In the ultrasonic propagation measurement mode, a reception trigger signal and an ultrasonic signal generated based on the selected M series are transmitted and correlation processing is performed. When the data processing circuit 206 detects the first peak of the correlation value, the elapsed time from the arrival time of the reception trigger signal to the time when the peak is detected, that is, the propagation time of the ultrasonic signal from the electronic pen 10 to the receiving unit 200. Is calculated.
（実施の形態の動作）
　次に、本発明の第１実施の形態における送信部１００の制御回路１０１の動作を図４および図５のフローチャートを参照して説明する。また、受信部２００のデータ処理回路２０６の動作を図６のフローチャートを参照して説明する。 (Operation of the embodiment)
Next, the operation of the control circuit 101 of the transmission unit 100 in the first embodiment of the present invention will be described with reference to the flowcharts of FIGS. The operation of the data processing circuit 206 of the receiving unit 200 will be described with reference to the flowchart of FIG.
　まず、Ｍ系列選択モードの場合について説明する。図４において、制御回路１０１は、互いに異なる複数のＭ系列から任意のＭ系列を選び、選んだＭ系列の初期条件を決定する（ステップ３０１）。 First, the case of the M sequence selection mode will be described. In FIG. 4, the control circuit 101 selects an arbitrary M sequence from a plurality of M sequences different from each other, and determines an initial condition of the selected M sequence (step 301).
　制御回路１０１は、決定した初期条件をＭ系列生成回路１０２へ供給する（ステップ３０２）。 The control circuit 101 supplies the determined initial condition to the M-sequence generation circuit 102 (step 302).
　また、制御回路１０１は、Ｍ系列の初期条件を決定すると、受信トリガ駆動回路１０５に対してトリガパルスの生成を受信トリガ駆動回路１０５に指示し、初期条件をコード化した初期条件データを供給する（ステップ３０３）。 When the control circuit 101 determines the M-sequence initial condition, the control circuit 101 instructs the reception trigger drive circuit 105 to generate a trigger pulse, and supplies initial condition data in which the initial condition is encoded. (Step 303).
　Ｍ系列生成回路１０２は、制御回路１０１が設定した初期条件に基づきＭ系列データを生成し（ステップ３０４）、超音波駆動回路１０３に供給する。 The M-sequence generation circuit 102 generates M-sequence data based on the initial conditions set by the control circuit 101 (step 304), and supplies it to the ultrasonic drive circuit 103.
　超音波駆動回路１０３は、Ｍ系列生成回路１０２から供給されたＭ系列データから超音波を変調するための駆動信号（変調信号）を生成する（ステップ３０５）。 The ultrasonic drive circuit 103 generates a drive signal (modulation signal) for modulating ultrasonic waves from the M-sequence data supplied from the M-sequence generation circuit 102 (step 305).
　受信トリガ駆動回路１０５は、制御回路１０１からのトリガパルスの生成指示により受信トリガ駆動信号を生成する（ステップ３０６）。 The reception trigger drive circuit 105 generates a reception trigger drive signal in response to a trigger pulse generation instruction from the control circuit 101 (step 306).
　ステップ３０３と３０４で両駆動信号が生成されると、受信トリガ送信機１０６と超音波送信機１０４は、受信トリガ駆動回路１０５と超音波駆動回路１０３の出力によりそれぞれ同時に駆動され、受信トリガ信号とＭ系列により変調された超音波信号を電子ペン１０から空間に送出する（ステップ３０７）。 When both drive signals are generated in steps 303 and 304, the reception trigger transmitter 106 and the ultrasonic transmitter 104 are simultaneously driven by the outputs of the reception trigger drive circuit 105 and the ultrasonic drive circuit 103, respectively. The ultrasonic signal modulated by the M series is transmitted from the electronic pen 10 to the space (step 307).
　ステップ３０７が実行されると、制御回路１０１は判定ステップ３０８で全てのＭ系列初期条件をチェックしたか否かを判定する。全Ｍ系列の送信が終了していなければ、制御回路１０１は、ステップ３０１に戻り次のＭ系列の初期条件を設定する。 When step 307 is executed, the control circuit 101 determines whether or not all M-sequence initial conditions have been checked in determination step 308. If transmission of all M sequences has not been completed, the control circuit 101 returns to step 301 and sets initial conditions for the next M sequence.
　従って、全Ｍ系列の送信が終了するまで、ステップ３０１から３０７が順次実行され、異なるＭ系列により変調された複数の超音波信号が順次送出される。 Therefore, steps 301 to 307 are sequentially executed until transmission of all M sequences is completed, and a plurality of ultrasonic signals modulated by different M sequences are sequentially transmitted.
　そして、各超音波信号の送出と同時に、これらのＭ系列の初期条件をコード化した初期条件データとトリガパルスにより変調された複数の受信トリガ信号が順次送出される。図２に示す１５ビットＭ系列で位相変調された超音波信号の場合、ステップ３０１から３０７の処理が１５回繰り返され１５種類のＭ系列データがチェックされる。 Simultaneously with the transmission of each ultrasonic signal, a plurality of reception trigger signals modulated by the trigger condition and initial condition data that encodes these M-sequence initial conditions are sequentially transmitted. In the case of the ultrasonic signal phase-modulated with the 15-bit M-sequence shown in FIG. 2, the processing of steps 301 to 307 is repeated 15 times to check 15 types of M-sequence data.
　全Ｍ系列の送信が終了すると（ステップ３０８）、全Ｍ系列のうち使用するＭ系列を選択する（ステップ３０９）。 When transmission of all M sequences ends (step 308), the M sequence to be used is selected from all M sequences (step 309).
　次に、超音波伝搬時間測定モードの場合について説明する。図５において、まず、制御回路１０１は、電子ペン１０が動作を開始すると（ステップ３１１）、Ｍ系列選択モードで選択されたＭ系列に対応するＭ系列の初期条件の中から送信周期毎に順次１つを決定し（ステップ３１２）、決定した初期条件をＭ系列生成回路１０２へ供給する（ステップ３１３）。 Next, the case of the ultrasonic propagation time measurement mode will be described. In FIG. 5, first, when the electronic pen 10 starts to operate (step 311), the control circuit 101 sequentially starts from the M-sequence initial conditions corresponding to the M-sequence selected in the M-sequence selection mode for each transmission cycle. One is determined (step 312), and the determined initial condition is supplied to the M-sequence generation circuit 102 (step 313).
　また、制御回路１０１は、Ｍ系列初期条件を決定すると、トリガパルスとＭ系列初期条件データを受信トリガ駆動回路１０５に供給し、受信トリガ信号の生成を指示する（ステップ３１４）。 Further, when the M-sequence initial condition is determined, the control circuit 101 supplies a trigger pulse and M-sequence initial condition data to the reception trigger drive circuit 105 and instructs generation of a reception trigger signal (step 314).
　Ｍ系列生成回路１０２は、供給された初期条件に基づきＭ系列データを生成し（ステップ３１５）、超音波駆動回路１０３に供給する。 The M-sequence generation circuit 102 generates M-sequence data based on the supplied initial conditions (Step 315), and supplies it to the ultrasonic drive circuit 103.
　超音波駆動回路１０３は、Ｍ系列生成回路１０２から供給されたＭ系列データから超音波を変調するための駆動信号（変調信号）を生成する（ステップ３１６）。 The ultrasonic drive circuit 103 generates a drive signal (modulation signal) for modulating the ultrasonic wave from the M-sequence data supplied from the M-sequence generation circuit 102 (step 316).
　また、受信トリガ駆動回路１０５は、受信トリガ駆動信号を生成する（ステップ３１７）。 Also, the reception trigger drive circuit 105 generates a reception trigger drive signal (step 317).
　ステップ３１６と３１７で両駆動信号が生成されると、受信トリガ送信機１０６と超音波送信機１０４は受信トリガ駆動回路１０５と超音波駆動回路１０３の出力によりそれぞれ同時に駆動され、受信トリガ信号とＭ系列により変調された超音波信号を電子ペン１０から空間に送出する（ステップ３１８）。 When both drive signals are generated in steps 316 and 317, the reception trigger transmitter 106 and the ultrasonic transmitter 104 are simultaneously driven by the outputs of the reception trigger drive circuit 105 and the ultrasonic drive circuit 103, respectively. The ultrasonic signal modulated by the series is sent from the electronic pen 10 to the space (step 318).
　ステップ３１８が実行されると、制御回路１０１は送信周期を決定するタイマーを駆動する（ステップ３１９）。制御回路１０１は次の送信時点を検出すると（ステップ３２０）、電子ペン１０の動作が終了したか否かを判定し（ステップ３２１）、動作中であれば、制御回路１０１はステップ３１２に戻り、次の送信周期の開始時点で再びＭ系列の初期条件を決定し、上述の動作を繰り返す。 When step 318 is executed, the control circuit 101 drives a timer for determining the transmission cycle (step 319). When the control circuit 101 detects the next transmission time (step 320), it determines whether or not the operation of the electronic pen 10 has been completed (step 321). If the operation is in operation, the control circuit 101 returns to step 312. The initial condition of the M sequence is determined again at the start of the next transmission cycle, and the above operation is repeated.
　電子ペン１０の動作が終了した場合、制御回路１０１はステップ３２１からステップ３１１に戻る。 When the operation of the electronic pen 10 is completed, the control circuit 101 returns from step 321 to step 311.
　受信部２００において、データ処理回路２０６が図６のフローチャートによる処理を実行する前に、サンプリング回路２０２は、超音波受信機２０１が受信した超音波信号を一定のサンプリング間隔でサンプル化し、サンプル化した超音波波形データをメモリ２０５に格納する。一方、検出回路２０４は、受信トリガ受信機２０３が受信した受信トリガ信号からトリガ検出信号とＭ系列初期条件データを検出し、メモリ２０５に格納する。 In the receiving unit 200, before the data processing circuit 206 executes the processing according to the flowchart of FIG. 6, the sampling circuit 202 samples the ultrasonic signal received by the ultrasonic receiver 201 at a constant sampling interval. Ultrasonic waveform data is stored in the memory 205. On the other hand, the detection circuit 204 detects a trigger detection signal and M-sequence initial condition data from the reception trigger signal received by the reception trigger receiver 203, and stores it in the memory 205.
　データ処理回路２０６は、トリガ検出信号をメモリ２０５から読出すと、サンプリングカウンタの値「ｔ」（サンプリング時刻）を「０」に設定する（ステップ４０１）。 The data processing circuit 206 reads the trigger detection signal from the memory 205, and sets the value “t” (sampling time) of the sampling counter to “0” (step 401).
　Ｍ系列初期条件をメモリに格納されている初期条件に設定し（ステップ４０２）、この初期条件に基づき図２にあるような位相変調によるＭ系列モデル波形を生成する（ステップ４０３）。データ処理回路２０６は、Ｍ系列選択中であれば（ステップ４０４）、相関開始時点（ts）を設定し（ステップ４０５）、相関値算出ステップ４０６に進む。 The M-sequence initial condition is set to the initial condition stored in the memory (step 402), and an M-sequence model waveform by phase modulation as shown in FIG. 2 is generated based on the initial condition (step 403). If the M sequence is being selected (step 404), the data processing circuit 206 sets the correlation start time (t s ) (step 405), and proceeds to the correlation value calculation step 406.
　ステップ４０６において、まずＮ個の受信超音波波形データがメモリ２０５から読み出され、ステップ４０３で生成されたモデル波形との間で相関計算が実行され、下記の式（１）に基づき相関値Ｃ（ｔ）が算出されメモリに格納される。
Figure JPOXMLDOC01-appb-M000001
 In step 406, first, N received ultrasonic waveform data are read from the memory 205, and correlation calculation is performed with the model waveform generated in step 403, and the correlation value C is calculated based on the following equation (1). (T) is calculated and stored in the memory.
Figure JPOXMLDOC01-appb-M000001
　式１において、ｉは整数値でサンプリング時刻を変数であり、Ｎはモデル波形のサンプリング数、ｒ（ｉ）はサンプリング時刻ｉのモデル波形の値、ｆ（ｉ＋ｔ）はサンプリング時刻（ｉ＋ｔ）の受信波形の値である。 In Equation 1, i is an integer value and the sampling time is a variable, N is the number of samplings of the model waveform, r (i) is the value of the model waveform at the sampling time i, and f (i + t) is the reception of the sampling time (i + t). The value of the waveform.
　相関処理開始から所定時間が経過したか否かが判定され（ステップ４０７）、経過していなければステップ４０８でサンプリング時刻ｔを単位量１だけ進ませステップ４０６に戻る。この相関計算は、所定時間が経過するまで実行されメモリ２０５に複数の相関値が格納される。 It is determined whether or not a predetermined time has elapsed since the start of the correlation process (step 407). If not, the sampling time t is advanced by the unit amount 1 in step 408, and the process returns to step 406. This correlation calculation is executed until a predetermined time elapses, and a plurality of correlation values are stored in the memory 205.
　相関開始から所定時間が経過すると、Ｍ系列選択中であるか否かが判定され（ステップ４０９）、Ｍ系列選択中であれば、メモリ２０５に格納されている相関値から最大の相関値（一次ピーク）を検出しその発生時点を超音波到達時点 (te)として設定する（ステップ４１０）。 When a predetermined time has elapsed from the start of correlation, it is determined whether or not the M series is being selected (step 409). If the M series is being selected, the maximum correlation value (primary value) is selected from the correlation values stored in the memory 205. A peak) is detected, and the time of occurrence is set as the ultrasonic arrival time (t e ) (step 410).
　ステップ４１１において、データ処理回路２０６は、下記の式（２）に基づき相関開始時点から超音波到達時点の直前に至る期間、即ち、
Figure JPOXMLDOC01-appb-M000002
 における最大の相関値を検出する。
Figure JPOXMLDOC01-appb-M000003
 In step 411, the data processing circuit 206, based on the following equation (2), a period from the correlation start time to immediately before the ultrasonic wave arrival time, that is,
Figure JPOXMLDOC01-appb-M000002
 The maximum correlation value at is detected.
Figure JPOXMLDOC01-appb-M000003
　ここで、P(n)はあるＭ系列の初期条件nの超音波到達時点以前の期間(
Figure JPOXMLDOC01-appb-M000004
 )の相関値C(t)の最大値を表す。例えば、この期間は到来した超音波の形状がモデル波形と部分的に一致する期間であり、この結果現れる相関値を副次ピークと称する。tsおよびteは限定するものではなく、任意に定めてもよい。検出された最大副次ピークはメモリ２０５に格納される。 Here, P (n) is a period before the ultrasonic arrival time of an initial condition n of an M series (
Figure JPOXMLDOC01-appb-M000004
 ) Represents the maximum value of the correlation value C (t). For example, this period is a period in which the shape of the incoming ultrasonic wave partially matches the model waveform, and the correlation value that appears as a result is referred to as a secondary peak. t s and t e are not limited and may be arbitrarily determined. The detected maximum secondary peak is stored in the memory 205.
　次に、メモリ２０５に格納された超音波データと全相関値はステップ４１２で消去され、次回到来する超音波データ、トリガ検出信号、Ｍ系列初期条件データを格納するための準備をする。 Next, the ultrasonic data and all correlation values stored in the memory 205 are erased in step 412, and preparations are made for storing the next incoming ultrasonic data, trigger detection signal, and M-sequence initial condition data.
　データ処理回路２０６は、全Ｍ系列の選択を終了したか否かを判定し（ステップ４１３）、終了していなければステップ４０１に戻り、次の受信トリガ信号と超音波信号の到来を検出するためメモリ２０５を監視し、トリガ検出信号を読出す。 The data processing circuit 206 determines whether or not the selection of all M sequences has been completed (step 413), and if not completed, returns to step 401 to detect the arrival of the next reception trigger signal and ultrasonic signal. The memory 205 is monitored and the trigger detection signal is read.
　全Ｍ系列の選択が終了していれば、データ処理回路２０６はステップ４１４に進み、メモリ２０５に格納されている全副次ピークのなかから副次ピークの小さい順に、それに対応するＭ系列を使用するＭ系列として選択し、Ｍ系列選択モードを終了しステップ４０１に戻る。 If the selection of all M series has been completed, the data processing circuit 206 proceeds to step 414, and uses the M series corresponding to the secondary peak in ascending order of all secondary peaks stored in the memory 205. Select as the M series, end the M series selection mode, and return to step 401.
　本発明の他の実施の形態として、送信側の制御回路１０１でＭ系列初期条件を決定すると予め設定されている特性多項式により自動的にＭ系列のビット列が決定されるが、Ｍ系列のビット配列を変更せずに１ビットシフトした配列になるようにしてもよい。 As another embodiment of the present invention, when an M-sequence initial condition is determined by the control circuit 101 on the transmission side, an M-sequence bit string is automatically determined by a preset characteristic polynomial. It is also possible to make an array shifted by 1 bit without changing the.
　図７は、上記の超音波受信波形と図２の１５ビットＭ系列モデル波形との相関値を示し、ステップ４１０において最大副次ピークが矢印の点で検出されたことを示す。 FIG. 7 shows the correlation value between the above-mentioned ultrasonic reception waveform and the 15-bit M-sequence model waveform of FIG. 2, and shows that the maximum secondary peak is detected at the point of the arrow in step 410.
　図８は、図２の１５ビットＭ系列において１ビット分シフトした１５ビットＭ系列のデータ列、即ち「０００１００１１０１０１１１１」により位相変調した超音波を用いた場合の相関値を示し最大副次ピークが矢印の点で検出されたことを示す。 FIG. 8 shows a correlation value when using a 15-bit M-sequence data string shifted by 1 bit in the 15-bit M-sequence of FIG. 2, that is, an ultrasonic wave phase-modulated by “000100110101111”, and the maximum secondary peak is an arrow. It is detected at the point.
　図９は、１５ビットＭ系列のデータ列「１００１１０１０１１１１０００」により位相変調した超音波を用いた場合の相関値を示し最大副次ピークが矢印の点で検出されたことを示す。 FIG. 9 shows a correlation value when an ultrasonic wave phase-modulated by a 15-bit M-sequence data string “100110101111000” is used, and shows that the maximum secondary peak is detected at the point of the arrow.
　図７から図９において、いずれもトリガパルスを受信した時点を「０」とし、サンプリング間隔は３．１２５μｓｅｃである。送信部１００と受信部２００が一定距離に保たれている限り超音波到達時点における相関値ピーク（主ピーク）は同一の時刻に現れる。 7 to FIG. 9, the time when the trigger pulse is received is “0”, and the sampling interval is 3.125 μsec. As long as the transmitter 100 and the receiver 200 are kept at a constant distance, the correlation value peak (main peak) at the time of arrival of the ultrasonic wave appears at the same time.
　超音波信号は伝搬距離により減衰するため、受信部２００で何周期前までの超音波信号を受信する可能性があるかを考慮して必要なＭ系列の個数を設定する必要がある。 Since the ultrasonic signal is attenuated by the propagation distance, it is necessary to set the necessary number of M series in consideration of how many cycles before the reception unit 200 may receive the ultrasonic signal.
　例えば、３周期前までの超音波信号を受信する可能性がある場合、最低でも４通りの異なるＭ系列が得られるようにしなければならないし、１周期前までの超音波信号を受信する可能性がある場合は、最低でも２通りの異なるＭ系列が得られるようにしなければならない。２通りの異なるＭ系列を選択する場合、図７から図９では最大副次ピークが小さいＭ系列「０００１００１１０１０１１１１」および「１００１１０１０１１１１０００」が使用するＭ系列として選択される。 For example, when there is a possibility of receiving an ultrasonic signal up to three cycles before, it is necessary to obtain at least four different M sequences, and the possibility of receiving an ultrasonic signal up to one cycle before If there is, at least two different M sequences must be obtained. When two different M sequences are selected, the M sequences “000100110101111” and “100110101111000” having the smallest maximum secondary peak are selected as M sequences to be used in FIGS.
　更に、本発明のさらに他の実施の形態として、異なる複数のＭ系列に対応して複数の異なる符号（またはインデックス）を割り当て、これらの符号とそれぞれを対応するＭ系列の初期条件と特性多項式に関連付けしたマッピングテーブルを受信部２００に備えることも可能である。 Furthermore, as yet another embodiment of the present invention, a plurality of different codes (or indexes) are allocated corresponding to a plurality of different M sequences, and these codes and the corresponding M sequence initial conditions and characteristic polynomials are assigned. It is possible to provide the receiving unit 200 with an associated mapping table.
　Ｍ系列選択モードの時、送信部１００は１つのＭ系列を送信する際このＭ系列に割り当てられた符号（インデックス）を受信トリガ信号により送信し、受信部２００は前記マッピングテーブルを参照し受信した符号に関連付けされたＭ系列初期条件と特性多項式を読み出す。 In the M sequence selection mode, the transmitting unit 100 transmits a code (index) assigned to this M sequence by a reception trigger signal when transmitting one M sequence, and the receiving unit 200 receives the reference by referring to the mapping table. The M-sequence initial condition and the characteristic polynomial associated with the code are read out.
　この方法により、少ない情報量でＭ系列初期条件と特性多項式を受信側に伝達することができる。マッピングテーブルに対応して、異なるＭ系列のビット列を割り当てても構わない。 This method can transmit the M-sequence initial condition and characteristic polynomial to the receiving side with a small amount of information. Different M-sequence bit strings may be assigned corresponding to the mapping table.
　上述のように決定されたＭ系列の初期条件は、送信部１００の制御回路１０１に設定され、超音波伝搬時間測定モードで使用される。従って、送信部１００は設定された複数のＭ系列を送信周期毎に巡回的に変更し、そのＭ系列に基づき受信トリガ信号と超音波信号を生成し受信部２００に送出する。 The initial conditions of the M sequence determined as described above are set in the control circuit 101 of the transmission unit 100 and used in the ultrasonic propagation time measurement mode. Therefore, the transmission unit 100 cyclically changes the set plurality of M sequences for each transmission cycle, generates a reception trigger signal and an ultrasonic signal based on the M sequences, and sends them to the reception unit 200.
　超音波伝搬時間測定モードにおいて、選択されたＭ系列の基づき生成された受信トリガ信号と超音波信号が送信部１００から送出されると、データ処理回路２０６は、ステップ４０１でトリガ検出信号をメモリ２０５から読出し、ステップ４０２でＭ系列初期条件をメモリに格納されている初期条件に設定し、Ｍ系列モデル波形を生成する（ステップ４０３）。 In the ultrasonic propagation time measurement mode, when the reception trigger signal and the ultrasonic signal generated based on the selected M series are transmitted from the transmission unit 100, the data processing circuit 206 stores the trigger detection signal in the memory 205 in step 401. In step 402, the M-sequence initial condition is set to the initial condition stored in the memory, and an M-sequence model waveform is generated (step 403).
　Ｍ系列選択モードでないため、データ処理回路２０６は、ステップ４０５を飛び越しステップ４０６に進み、前述のように１サンプル分のＭ系列超音波データをメモリ２０５から読出し、ステップ４０３で生成されたＭ系列モデル波形との間で相関計算を実行し、式（１）に基づき相関値C(t)を算出しメモリ２０５に格納する。 Since it is not in the M-sequence selection mode, the data processing circuit 206 skips step 405 and proceeds to step 406 to read M-sequence ultrasonic data for one sample from the memory 205 as described above, and generate the M-sequence model generated in step 403. Correlation calculation with the waveform is executed, and a correlation value C (t) is calculated based on the equation (1) and stored in the memory 205.
　データ処理回路２０６は、所定時間が経過するまでステップ４０６を実行し、ステップ４０７からステップ４０９に進む。ステップ４０９では、既にＭ系列選択モードを終了しているので、ステップ４１５からの処理が実行される。 The data processing circuit 206 executes step 406 until a predetermined time elapses, and proceeds from step 407 to step 409. In step 409, since the M-sequence selection mode has already been completed, the processing from step 415 is executed.
　ステップ４１５において、データ処理回路２０６は、所定時間内に算出された全相関値から副次ピークの値より大きな所定値以上の相関値を選択し、この中から先頭ピークを検出する。 In step 415, the data processing circuit 206 selects a correlation value greater than or equal to a predetermined value larger than the value of the secondary peak from all correlation values calculated within a predetermined time, and detects the top peak from the correlation value.
　先頭ピークを検出した時点のサンプリング時刻(tf)を先頭ピーク検出時点として設定し（ステップ４１６）、超音波伝搬時間(tf
× ΔT)算出する（ステップ４１７）。次に、ステップ４１８で全てのデータをメモリ２０５から消去する。 The sampling time (t f ) at the time when the first peak is detected is set as the first peak detection time (step 416), and the ultrasonic wave propagation time (t f
× ΔT) is calculated (step 417). Next, in step 418, all data is erased from the memory 205.
　以下、上述ように測定された超音波伝播時間から移動体である電子ペン１０の位置を検出するデータ処理回路２０６による処理の例について説明する。 Hereinafter, an example of processing by the data processing circuit 206 that detects the position of the electronic pen 10 that is a moving body from the ultrasonic propagation time measured as described above will be described.
　図１０は、電子ペン１０と超音波受信機２０１－１、２０１－２との位置算出方法を２次元で示す図である。図１０において、Ｐは電子ペン１０の描画可能範囲上のｘ－ｙ座標における位置座標値（ｘ，ｙ）、Ｓ１、Ｓ２はそれぞれ超音波受信部２０１－１、２０１－２の位置を示している。 FIG. 10 is a diagram showing two-dimensionally the position calculation method between the electronic pen 10 and the ultrasonic receivers 201-1 and 201-2. In FIG. 10, P is the position coordinate value (x, y) in the xy coordinates on the drawable range of the electronic pen 10, and S1 and S2 are the positions of the ultrasonic receiving units 201-1 and 201-2, respectively. Yes.
　また、ｄ１は電子ペン１０から超音波受信機２０１－１までの距離、ｄ２は電子ペン１０から超音波受信機２０１－２までの距離である。Ｄは超音波受信機２０１－１、２０１－２の中央をｘ－ｙ座標の原点とした場合の原点からの距離である。また、αは電子ペン１０と超音波受信機２０１－１とを結ぶ直線がｘ軸となす角度を示している。 D1 is the distance from the electronic pen 10 to the ultrasonic receiver 201-1 and d2 is the distance from the electronic pen 10 to the ultrasonic receiver 201-2. D is the distance from the origin when the center of the ultrasonic receivers 201-1 and 201-2 is the origin of the xy coordinates. Α represents an angle formed by a straight line connecting the electronic pen 10 and the ultrasonic receiver 201-1 with the x-axis.
　ここで、超音波受信機２０１－１と２０１－２で受信した超音波信号に基づいて算出した超音波伝搬時間をそれぞれｔ１、ｔ２とし、また、音速をＡとする。 Here, the ultrasonic propagation times calculated based on the ultrasonic signals received by the ultrasonic receivers 201-1 and 201-2 are t1 and t2, respectively, and the sound velocity is A.
　距離ｄ１、ｄ２は、ｄ１＝Ａ×ｔ１、ｄ２＝Ａ×ｔ２として算出することができる。超音波受信機２０１－１と２０１－２間の間隔長（２Ｄ）と距離ｄ１、ｄ２の間には、図１０に示す関係が成立していることから、電子ペン１０の位置（ｘ、ｙ）を計算により求めることができる。 The distances d1 and d2 can be calculated as d1 = A × t1 and d2 = A × t2. Since the relationship shown in FIG. 10 is established between the interval length (2D) between the ultrasonic receivers 201-1 and 201-2 and the distances d1 and d2, the position (x, y) of the electronic pen 10 is established. ) Can be obtained by calculation.
　また、超音波受信機を３個以上にすることで、３次元上の位置を特定することも可能である。 Also, it is possible to specify a three-dimensional position by using three or more ultrasonic receivers.
　図１１は、超音波伝搬時間測定モードにおける受信部２００の動作を説明する図である。各測定周期で直接波の他に前の周期の反射波も受信しているが、副次ピークが小さいＭ系列超音波を使用することで、前の周期の反射波と今回の周期のＭ系列モデル波形との相互相関値のピークと副次ピークが重なっても直接波のピークを検知することが可能になる。 FIG. 11 is a diagram for explaining the operation of the receiving unit 200 in the ultrasonic propagation time measurement mode. In each measurement period, the reflected wave of the previous period is also received in addition to the direct wave, but the reflected wave of the previous period and the M series of the current period can be obtained by using M-sequence ultrasonic waves having a small secondary peak. Even if the peak of the cross-correlation value with the model waveform overlaps with the secondary peak, the peak of the direct wave can be detected.
　一方、Ｍ系列選択モードにおいて、受信装置２０において、受信トリガ信号と超音波信号を受信する毎に、超音波信号に使用する全てのＭ系列モデル波形との相関値をそれぞれ求め、異なるＭ系列間の相互相関値をチェックする。その際、相互相関値のピークの値が小さいＭ系列データほど高く評価し、全Ｍ系列の相互相関値のピークが小さいほうから、その相互相関値に対するＭ系列の組み合わせを形成するＭ系列（初期条件）を、使用するＭ系列として割り当ててもよい。 On the other hand, in the M-sequence selection mode, each time the reception device 20 receives the reception trigger signal and the ultrasonic signal, the correlation value between all the M-sequence model waveforms used for the ultrasonic signal is obtained. Check the cross-correlation value. At that time, M-sequence data with a smaller cross-correlation value peak value is evaluated higher, and the M-sequence (initial stage) that forms a combination of M-sequences with respect to the cross-correlation value from the smaller cross-correlation value peak of all M sequences Condition) may be assigned as the M sequence to be used.
　さらに、副次ピークの小さいＭ系列のうち、相互相関値が低い組み合わせを選択し、使用するＭ系列として割り当ててもよい。 Furthermore, a combination having a low cross-correlation value may be selected from the M sequences having a small secondary peak and assigned as the M sequence to be used.
（第１の実施の形態の効果）
　上述した第１の実施の形態によれば、副次ピークが小さいＭ系列超音波を使用することで、前の周期の反射波と今回の周期のＭ系列モデル波形との相互相関値のピークと副次ピークが重なっても直接波のピークを検知することが可能になるので、超音波信号の反射波の影響を受けることなく、超音波発信源から最も先に到達する直接波の伝搬時間を正確に算出することが可能となる。 (Effects of the first embodiment)
According to the first embodiment described above, by using M-sequence ultrasound with a small secondary peak, the peak of the cross-correlation value between the reflected wave of the previous cycle and the M-sequence model waveform of the current cycle Since it is possible to detect the peak of the direct wave even if the secondary peaks overlap, the propagation time of the direct wave that reaches the earliest from the ultrasonic wave source can be reduced without being affected by the reflected wave of the ultrasonic signal. It is possible to calculate accurately.
　ここで、電子ペン１０の送信部１００及び受信装置２０の受信部２００のハードウェア構成例について、図１２を参照して説明する。 Here, a hardware configuration example of the transmission unit 100 of the electronic pen 10 and the reception unit 200 of the reception device 20 will be described with reference to FIG.
　図１２を参照すると、送信部１００及び受信部２００は、一般的なコンピュータ装置と同様のハードウェア構成によって実現することができ、ＣＰＵ（Central Processing Unit）４０１、ＲＡＭ（Random Access Memory）等のメインメモリであり、データの作業領域やデータの一時退避領域に用いられる主記憶部４０２、電磁波信号と超音波信号の送信機と受信機として機能する通信部４０３、入力装置４０５、出力装置４０６及び記憶装置４０７と接続してデータの送受信を行う入出力インタフェース部４０４、上記各構成要素を相互に接続するシステムバス４０８を備えている。記憶装置４０７は、例えば、ＲＯＭ（Read
Only Memory）、磁気ディスク、半導体メモリ等の不揮発性メモリから構成されるハードディスク装置等で実現される。 Referring to FIG. 12, the transmission unit 100 and the reception unit 200 can be realized by a hardware configuration similar to that of a general computer device. Main components such as a CPU (Central Processing Unit) 401 and a RAM (Random Access Memory) are provided. A main memory unit 402 used as a data work area and a temporary data save area, a communication unit 403 functioning as a transmitter and receiver of electromagnetic wave signals and ultrasonic signals, an input device 405, an output device 406, and a memory An input / output interface unit 404 that is connected to the apparatus 407 and transmits / receives data, and a system bus 408 that connects the above components to each other are provided. The storage device 407 is, for example, a ROM (Read
Only Memory), a hard disk device including a non-volatile memory such as a magnetic disk and a semiconductor memory.
　本実施の形態による位置検出システムは、コンピュータに、図１に示す各手段の機能を実現する位置検出プログラムを組み込んだ、ＬＳＩ（Large Scale Integration）等のハードウェア部品である回路部品を実装することにより、その動作をハードウェア的に実現することは勿論として、位置検出プログラムを、記憶装置４０７に格納し、そのプログラムを主記憶部４０２にロードしてＣＰＵ４０１で実行することにより、ソフトウェア的に実現することも可能である。 In the position detection system according to the present embodiment, a circuit component which is a hardware component such as an LSI (Large Scale Integration) in which a position detection program for realizing the function of each unit shown in FIG. As a matter of course, the operation is realized in hardware, the position detection program is stored in the storage device 407, and the program is realized by loading the program into the main storage unit 402 and executing it by the CPU 401. It is also possible to do.
　以上、好ましい実施の形態と実施例をあげて本発明を説明したが、本発明は必ずしも、上記実施の形態及び実施例に限定されるものでなく、その技術的思想の範囲内において様々に変形して実施することができる。 The present invention has been described above with reference to preferred embodiments and examples. However, the present invention is not necessarily limited to the above embodiments and examples, and various modifications can be made within the scope of the technical idea. Can be implemented.
　上記各実施の形態では、本発明を電子ペンシステムに適用した場合について説明したが、ロボットシステムへ適用することが可能である。送信装置をロボットへ設置し、受信装置をある空間の天井や壁に設置することでロボットの空間内の位置を検出することができる。空間内のロボットの位置を把握することでロボットを制御し衝突回避といった用途に使用可能である。 In each of the above embodiments, the case where the present invention is applied to an electronic pen system has been described. However, the present invention can be applied to a robot system. The position of the robot in the space can be detected by installing the transmitter on the robot and installing the receiver on the ceiling or wall of a certain space. By grasping the position of the robot in space, the robot can be controlled and used for collision avoidance.
　一方、送信装置を人間等に装着し、受信装置をある空間の天井や壁に設置することで、空間内での動線検出や位置追跡といった用途にも適用することができる。 On the other hand, by installing the transmitting device on a person or the like and installing the receiving device on the ceiling or wall of a certain space, it can be applied to applications such as detection of flow lines and position tracking in the space.
　これまでは、Ｍ系列による変調について述べたが、例えばＧｏｌｄ系列のように、自己相関性が高く、他の系列との相互相関が低い擬似ランダム信号であれば、Ｍ系列に限定するものではない。 So far, modulation by M sequence has been described, but it is not limited to M sequence as long as it is a pseudo-random signal having high autocorrelation and low cross-correlation with other sequences such as Gold sequence, for example. .
　この出願は、２００８年７月２５日に出願された日本出願特願２００８－１９１８８０を基礎とする優先権を主張し、その開示の全てをここに取り込む。
  This application claims priority based on Japanese Patent Application No. 2008-191880 filed on Jul. 25, 2008, the entire disclosure of which is incorporated herein.

Claims (42)

  1. 　自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を送出する送信部を含む移動体と、
    　前記超音波信号を受信し、前記擬似ランダム信号と同じ擬似ランダム信号により変調された超音波のモデル波形を生成し、受信した超音波信号との間で相関値を求め、該超音波信号が該擬似ランダム信号モデル波形と部分的に一致したときに現れる相関値の副次ピークが小さいほうから対応する前記擬似ランダム信号を複数選択する受信部とを具備し、
    　前記送信部は、
    　電磁波信号と、前記選択された擬似ランダム信号に基づき変調された超音波信号とを同時に送出する手段を備え、
    　前記受信部は、
    　該超音波信号と前記擬似ランダム信号により変調された超音波モデル波形との間で相関処理を実行することにより前記超音波信号の到達時間を特定し、前記電磁波信号の到着時点と特定された到達時間とから超音波の伝搬時間を算出する手段と、
    　算出した前記超音波伝播時間と超音波受信手段相互の間隔長に基づいて、前記移動体の位置を算出する手段とを備え、
    　前記送信部は、送信周期毎に異なる擬似ランダム信号を使用することを特徴とする位置検出システム。     A moving body including a transmitter that transmits an ultrasonic signal modulated based on a pseudorandom signal having high autocorrelation;
    The ultrasonic signal is received, an ultrasonic model waveform modulated by the same pseudo-random signal as the pseudo-random signal is generated, a correlation value is obtained with the received ultrasonic signal, and the ultrasonic signal is A receiver that selects a plurality of the corresponding pseudo-random signals from the smaller secondary peak of the correlation value that appears when the waveform partially matches the pseudo-random signal model waveform,
    The transmitter is
    Means for simultaneously transmitting an electromagnetic wave signal and an ultrasonic signal modulated based on the selected pseudo-random signal;
    The receiver is
    The arrival time of the ultrasonic signal is specified by performing correlation processing between the ultrasonic signal and the ultrasonic model waveform modulated by the pseudo-random signal, and the arrival time specified as the arrival time of the electromagnetic wave signal Means for calculating the propagation time of the ultrasonic wave from the time,
    Means for calculating the position of the moving body based on the calculated ultrasonic propagation time and the interval length between the ultrasonic receiving means;
    The position detection system, wherein the transmission unit uses a different pseudo-random signal for each transmission period.
  2. 　前記擬似ランダム信号が、Ｍ系列であることを特徴とする請求項１に記載の位置検出システム。 The position detection system according to claim 1, wherein the pseudo-random signal is an M series.
  3. 　前記送信部が、
    　互いに異なる複数のＭ系列から選択した任意のＭ系列を規定するデータに基づき生成されたＭ系列データによって変調された超音波信号と、前記Ｍ系列を規定するデータを含む電磁波信号を送出することを特徴とする請求項２に記載の位置検出システム。     The transmitter is
    Transmitting an ultrasonic signal modulated by M-sequence data generated based on data defining an arbitrary M-sequence selected from a plurality of different M-sequences, and an electromagnetic wave signal including the data defining the M-sequence The position detection system according to claim 2.
  4. 　前記送信部が、
    　送信タイミングとＭ系列を規定するデータを送信周期毎に決定し、該送信タイミングを表すトリガ信号と該Ｍ系列を規定するデータを含む電磁波信号を空間に送出する電磁波送信手段と、
    　前記送信周期毎に決定されるＭ系列を規定するデータに基づきＭ系列波形を生成し、Ｍ系列波形の超音波信号を前記電磁波信号と同時に空間に送出する超音波送信手段を備え、
    　前記受信部が、
    　送出された前記超音波信号を受信し、Ｍ系列波形を出力する超音波受信手段と、
    　受信した前記電磁波信号から前記トリガ信号と前記Ｍ系列を規定するデータを検出する検出手段と、
    　前記検出手段により検出した前記Ｍ系列を規定するデータと前記超音波受信手段が出力したＭ系列波形を格納する記憶回路と、
    　前記記憶回路からＭ系列を規定するデータを読み出し、Ｍ系列モデル波形を生成し、格納されたＭ系列データを順次読み出し該Ｍ系列モデル波形との間で相関値を算出し、算出された相関値の最初の相関ピーク値を検出し、前記トリガ信号を受信した時点と該相関ピーク値の検出時点とから超音波伝搬時間を決定すると共に、前記超音波伝播時間と超音波受信手段相互の間隔長に基づいて、前記移動体の位置を算出するデータ処理回路を備えることを特徴とする請求項２又は請求項３に記載の位置検出システム。     The transmitter is
    Electromagnetic wave transmission means for determining data for defining a transmission timing and an M-sequence for each transmission cycle, and transmitting an electromagnetic wave signal including a trigger signal indicating the transmission timing and data for defining the M-sequence to a space;
    An ultrasonic transmission means for generating an M-sequence waveform based on data defining an M-sequence determined for each transmission period, and transmitting an ultrasonic signal of the M-sequence waveform to the space simultaneously with the electromagnetic wave signal;
    The receiver is
    Ultrasonic receiving means for receiving the transmitted ultrasonic signal and outputting an M-sequence waveform;
    Detecting means for detecting data defining the trigger signal and the M-sequence from the received electromagnetic wave signal;
    A storage circuit for storing data defining the M-sequence detected by the detection means and an M-sequence waveform output by the ultrasonic reception means;
    Reading data defining the M series from the storage circuit, generating an M series model waveform, sequentially reading the stored M series data, calculating a correlation value with the M series model waveform, and calculating the calculated correlation value The first correlation peak value is detected, the ultrasonic propagation time is determined from the time when the trigger signal is received and the detection time of the correlation peak value, and the interval length between the ultrasonic propagation time and the ultrasonic receiving means is determined. The position detection system according to claim 2, further comprising: a data processing circuit that calculates a position of the moving body based on the position.
  5. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列初期条件データであることを特徴とする請求項２から請求項４の何れかに記載の位置検出システム。 5. The position detection system according to claim 2, wherein the data defining the M series included in the electromagnetic wave signal is M series initial condition data.
  6. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列の特性多項式と初期条件データとあることを特徴とする請求項２から請求項４の何れかに記載の位置検出システム。 5. The position detection system according to claim 2, wherein the data defining the M series included in the electromagnetic wave signal includes an M series characteristic polynomial and initial condition data.
  7. 　前記超音波信号をＭ系列データにより位相変調することを特徴とする請求項２から請求項６の何れかに記載の位置検出システム。 The position detection system according to any one of claims 2 to 6, wherein the ultrasonic signal is phase-modulated by M-sequence data.
  8. 　前記電磁波信号として赤外線を送信することを特徴とする請求項１から請求項７の何れかに記載の位置検出システム。 The position detection system according to any one of claims 1 to 7, wherein infrared rays are transmitted as the electromagnetic wave signal.
  9. 　前記移動体が電子ペンであることを特徴とする請求項１から請求項８の何れかに記載の位置検出システム。 9. The position detection system according to claim 1, wherein the moving body is an electronic pen.
  10. 　前記移動体がロボットであることを特徴とする請求項１から請求項８の何れかに記載の位置検出システム。 The position detection system according to any one of claims 1 to 8, wherein the moving body is a robot.
  11. 　送信装置から送信される超音波信号を受信装置で受信して前記送信装置の位置を検出する位置検出システムの前記送信装置であって、
    　自己相関性の高い擬似ランダム信号に基づき変調された第１の超音波信号を送出する手段と、
    　送信タイミングを表す電磁波信号と、前記受信装置で選択された擬似ランダム信号に基づき変調された第２の超音波信号とを同時に送出する手段を備え、
    　送信周期毎に異なる擬似ランダム信号を使用することを特徴とする送信装置。     The transmission device of a position detection system that receives an ultrasonic signal transmitted from a transmission device by a reception device and detects a position of the transmission device,
    Means for transmitting a first ultrasonic signal modulated based on a pseudorandom signal having high autocorrelation;
    Means for simultaneously transmitting an electromagnetic wave signal representing transmission timing and a second ultrasonic signal modulated based on a pseudo-random signal selected by the receiver;
    A transmission apparatus using a different pseudo-random signal for each transmission cycle.
  12. 　前記擬似ランダム信号が、Ｍ系列であることを特徴とする請求項１１に記載の送信装置。 The transmission apparatus according to claim 11, wherein the pseudo-random signal is an M sequence.
  13. 　互いに異なる複数のＭ系列から選択した任意のＭ系列を規定するデータに基づき生成されたＭ系列データによって変調された超音波信号と、前記Ｍ系列を規定するデータを含む電磁波信号を送出することを特徴とする請求項１２に記載の送信装置。 Transmitting an ultrasonic signal modulated by M-sequence data generated based on data defining an arbitrary M-sequence selected from a plurality of different M-sequences, and an electromagnetic wave signal including the data defining the M-sequence. The transmission device according to claim 12, characterized in that:
  14. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列初期条件データであることを特徴とする請求項１２又は請求項１３に記載の送信装置。 14. The transmission device according to claim 12, wherein the data defining the M series included in the electromagnetic wave signal is M series initial condition data.
  15. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列の特性多項式と初期条件データとあることを特徴とする請求項１２又は請求項１３に記載の送信装置。 14. The transmission apparatus according to claim 12, wherein the data defining the M series included in the electromagnetic wave signal includes an M series characteristic polynomial and initial condition data.
  16. 　前記超音波信号をＭ系列データにより位相変調することを特徴とする請求項１２から請求項１５の何れかに記載の送信装置。 The transmitter according to any one of claims 12 to 15, wherein the ultrasonic signal is phase-modulated with M-sequence data.
  17. 　前記電磁波信号として赤外線を送信することを特徴とする請求項１１から請求項１６の何れかに記載の送信装置。 The transmission device according to any one of claims 11 to 16, wherein infrared rays are transmitted as the electromagnetic wave signal.
  18. 　送信装置から送信される超音波信号を受信装置で受信し前記送信装置の位置を検出する位置検出システムの前記受信装置であって、
    　前記送信装置から送信される自己相関性の高い擬似ランダム系列のデータにより変調された第１の超音波信号を受信し、前記擬似ランダム信号と同じ擬似ランダム信号により変調された超音波のモデル波形を生成し、受信した超音波信号との間で相関値を求め、該超音波信号が該擬似ランダム信号モデル波形と部分的に一致したときに現れる相関値の副次ピークが小さいほうから対応する前記擬似ランダム信号を複数選択する手段と、
    　前記送信装置から同時に送出される電磁波信号と、前記受信装置で選択した擬似ランダム信号に基づき変調された第２の超音波信号を受信し、該第２の超音波信号と前記擬似ランダム信号により変調された超音波モデル波形との間で相関処理を実行することにより前記超音波信号の到達時間を特定し、前記電磁波信号の到着時点と特定された到達時間とから超音波の伝搬時間を算出する手段と、
    　算出した前記超音波伝播時間と前記超音波受信手段相互の間隔長に基づいて、前記移動体の位置を算出する手段と
    　を備えることを特徴とする受信装置。     The reception device of the position detection system that receives an ultrasonic signal transmitted from a transmission device by a reception device and detects the position of the transmission device,
    A first ultrasonic signal modulated by pseudo-random sequence data with high autocorrelation transmitted from the transmission device is received, and an ultrasonic model waveform modulated by the same pseudo-random signal as the pseudo-random signal is received. The correlation value between the generated ultrasonic signal and the received ultrasonic signal is obtained, and the secondary peak of the correlation value that appears when the ultrasonic signal partially matches the pseudo-random signal model waveform Means for selecting a plurality of pseudo-random signals;
    Receives an electromagnetic wave signal transmitted simultaneously from the transmitter and a second ultrasonic signal modulated based on the pseudo-random signal selected by the receiver, and modulates the second ultrasonic signal and the pseudo-random signal. The arrival time of the ultrasonic signal is specified by executing a correlation process with the determined ultrasonic model waveform, and the propagation time of the ultrasonic wave is calculated from the arrival time of the electromagnetic wave signal and the specified arrival time Means,
    A receiving device comprising: means for calculating the position of the moving body based on the calculated ultrasonic propagation time and the interval length between the ultrasonic receiving means.
  19. 　前記擬似ランダム信号が、Ｍ系列であることを特徴とする請求項１８に記載の受信装置。 The receiving apparatus according to claim 18, wherein the pseudo-random signal is an M sequence.
  20. 　前記送信装置から、互いに異なる複数のＭ系列から選択した任意のＭ系列を規定するデータに基づき生成されたＭ系列データによって変調された超音波信号と、前記Ｍ系列を規定するデータを含む電磁波信号を受信することを特徴とする請求項１９に記載の受信装置。 An ultrasonic signal modulated by M sequence data generated based on data defining an arbitrary M sequence selected from a plurality of different M sequences from the transmitter, and an electromagnetic wave signal including data defining the M sequence The receiving apparatus according to claim 19, wherein:
  21. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列初期条件データであることを特徴とする請求項１９又は請求項２０に記載の受信装置。 21. The receiving apparatus according to claim 19, wherein the data defining the M series included in the electromagnetic wave signal is M series initial condition data.
  22. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列の特性多項式と初期条件データとあることを特徴とする請求項１９又は請求項２０に記載の受信装置。 21. The receiving apparatus according to claim 19, wherein the data defining the M series included in the electromagnetic wave signal includes an M series characteristic polynomial and initial condition data.
  23. 　前記超音波信号をＭ系列データにより位相変調することを特徴とする請求項１９から請求項２２の何れかに記載の受信装置。 The receiving apparatus according to any one of claims 19 to 22, wherein the ultrasonic signal is phase-modulated by M-sequence data.
  24. 　前記電磁波信号として赤外線を送信することを特徴とする請求項１８から請求項２３の何れかに記載の受信装置。 24. The receiving device according to claim 18, wherein infrared rays are transmitted as the electromagnetic wave signal.
  25. 　ａ）自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を移動体の送信部から送出するステップと、
    　ｂ）受信部で前記超音波信号を受信し、前記擬似ランダム信号により変調された超音波のモデル波形を生成し、該モデル波形と受信した超音波信号との間で相関処理を実行し相関波形を検出するステップと、
    　ｃ）異なる擬似ランダム信号について、前記相関波形を複数検出し、前記モデル波形と受信超音波信号とが部分的に一致した際に各相関波形に現れる副次ピークが小さいほうから対応する前記擬似ランダム信号を複数選択するステップと、
    　ｄ）前記ステップ（ｃ）で選択された擬似ランダム信号に基づき変調された超音波信号と、送信タイミングを表すトリガ信号と該擬似ランダム信号を規定するデータを含む電磁波信号とを一定送信周期毎に同時に前記移動体から送出するステップと、
    　ｅ）該電磁波信号を受信し該電磁波信号が含む擬似ランダム信号を規定するデータから前記擬似ランダム信号により変調された超音波モデル波形を生成するステップと、
    　ｆ）前記超音波信号を受信し、受信した超音波信号とステップ（ｅ）で生成された前記超音波モデル波形との間で相関値を算出するステップと、
    　ｇ）算出した前記超音波伝播時間と前記超音波受信手段相互の間隔長に基づいて、前記移動体の位置を算出するステップとを含み、
    　ステップ（ｄ）は送信周期毎に異なる擬似ランダム信号を使用することを特徴とする位置検出方法。     a) transmitting an ultrasonic signal modulated based on a pseudo-random signal having a high autocorrelation from a transmitter of the moving body;
    b) The reception unit receives the ultrasonic signal, generates an ultrasonic model waveform modulated by the pseudo-random signal, executes correlation processing between the model waveform and the received ultrasonic signal, and generates a correlation waveform Detecting steps,
    c) For a plurality of different pseudo-random signals, a plurality of the correlation waveforms are detected, and when the model waveform and the received ultrasonic signal partially match, the corresponding pseudo-random ones corresponding to the smaller secondary peaks appearing in the correlation waveforms. Selecting a plurality of signals;
    d) An ultrasonic signal modulated based on the pseudo-random signal selected in the step (c), a trigger signal indicating transmission timing, and an electromagnetic wave signal including data defining the pseudo-random signal are transmitted at fixed transmission cycles. Simultaneously sending from the mobile;
    e) receiving the electromagnetic wave signal and generating an ultrasonic model waveform modulated by the pseudo random signal from data defining a pseudo random signal included in the electromagnetic wave signal;
    f) receiving the ultrasonic signal, calculating a correlation value between the received ultrasonic signal and the ultrasonic model waveform generated in step (e);
    g) calculating the position of the moving body based on the calculated ultrasonic propagation time and the interval length between the ultrasonic receiving means,
    Step (d) uses a different pseudo-random signal for each transmission cycle.
  26. 　前記擬似ランダム信号がＭ系列であることを特徴とする請求項２５に記載の位置検出方法。 The position detection method according to claim 25, wherein the pseudo-random signal is an M series.
  27. 　前記送信部が、
    　互いに異なる複数のＭ系列から選択した任意のＭ系列を規定するデータに基づき生成されたＭ系列データによって変調された超音波信号と、前記Ｍ系列を規定するデータを含む電磁波信号を送出することを特徴とする請求項２６に記載の位置検出方法。     The transmitter is
    Transmitting an ultrasonic signal modulated by M-sequence data generated based on data defining an arbitrary M-sequence selected from a plurality of different M-sequences, and an electromagnetic wave signal including the data defining the M-sequence The position detection method according to claim 26, characterized in that:
  28. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列初期条件データであることを特徴とする請求項２６又は請求項２７に記載の位置検出方法。 28. The position detection method according to claim 26, wherein the data defining the M series included in the electromagnetic wave signal is M series initial condition data.
  29. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列の特性多項式と初期条件データとあることを特徴とする請求項２６又は請求項２７に記載の位置検出方法。 28. The position detection method according to claim 26, wherein the data defining the M series included in the electromagnetic wave signal includes an M series characteristic polynomial and initial condition data.
  30. 　前記超音波信号をＭ系列データにより位相変調することを特徴とする請求項２６から請求項２９の何れかに記載の位置検出方法。 30. The position detection method according to claim 26, wherein the ultrasonic signal is phase-modulated with M-sequence data.
  31. 　前記電磁波信号として赤外線を送信することを特徴とする請求項２５から請求項３０の何れかに記載の位置検出方法。 The position detection method according to any one of claims 25 to 30, wherein infrared rays are transmitted as the electromagnetic wave signal.
  32. 　前記移動体が電子ペンであることを特徴とする請求項２５から請求項３１の何れかに記載の位置検出方法。 32. The position detection method according to claim 25, wherein the moving body is an electronic pen.
  33. 　前記移動体がロボットであることを特徴とする請求項２５から請求項３１の何れかに記載の位置検出方法。 32. The position detecting method according to claim 25, wherein the moving body is a robot.
  34. 　移動体に備えられた送信装置を構成するコンピュータに、
    　自己相関性の高い擬似ランダム信号に基づき変調された超音波信号を移動体の送信部から送出する処理を実行させ、
    　受信装置を構成をするコンピュータに、
    　前記超音波信号を受信し、前記擬似ランダム信号により変調された超音波のモデル波形を生成し、該モデル波形と受信した超音波信号との間で相関処理を実行し相関波形を検出する処理と、
    　異なる擬似ランダム信号について、前記相関波形を複数検出し、前記モデル波形と受信超音波信号とが部分的に一致した際に各相関波形に現れる副次ピークが小さいほうから対応する前記擬似ランダム信号を複数選択する処理とを実行させ、
    　前記送信装置を構成するコンピュータに、
    　選択された擬似ランダム信号に基づき変調された超音波信号と、送信タイミングを表すトリガ信号と該擬似ランダム信号を規定するデータを含む電磁波信号とを一定送信周期毎に同時に前記移動体から送出する処理を実行させ、
    　前記受信装置を構成をするコンピュータに、
    　該電磁波信号を受信し該電磁波信号が含む擬似ランダム信号を規定するデータから前記擬似ランダム信号により変調された超音波モデル波形を生成する処理と、
    　前記超音波信号を受信し、受信した超音波信号と生成された前記超音波モデル波形との間で相関値を算出する処理と、
    　算出した前記超音波伝播時間と前記超音波受信手段相互の間隔長に基づいて、前記移動体の位置を算出する処理を実行させ、
    　前記送信装置からの前記超音波信号の送出において、送信周期毎に異なる擬似ランダム信号を使用することを特徴とする位置検出プログラム。     In a computer constituting a transmission device provided in a mobile body,
    A process of transmitting an ultrasonic signal modulated based on a pseudo-random signal having a high autocorrelation from a transmitting unit of a moving object;
    To the computer that configures the receiving device,
    Receiving the ultrasonic signal, generating an ultrasonic model waveform modulated by the pseudo-random signal, executing correlation processing between the model waveform and the received ultrasonic signal, and detecting a correlation waveform; ,
    A plurality of the correlation waveforms are detected for different pseudo-random signals, and the corresponding pseudo-random signals corresponding to the smaller secondary peak appearing in each correlation waveform when the model waveform and the received ultrasonic signal partially coincide with each other. Process to select multiple,
    In the computer constituting the transmission device,
    A process of simultaneously transmitting an ultrasonic signal modulated based on the selected pseudo-random signal, a trigger signal indicating transmission timing, and an electromagnetic wave signal including data defining the pseudo-random signal from the moving body at regular intervals And execute
    In a computer constituting the receiving device,
    Processing for receiving the electromagnetic wave signal and generating an ultrasonic model waveform modulated by the pseudo random signal from data defining a pseudo random signal included in the electromagnetic wave signal;
    Processing for receiving the ultrasonic signal and calculating a correlation value between the received ultrasonic signal and the generated ultrasonic model waveform;
    Based on the calculated ultrasonic propagation time and the interval length between the ultrasonic receiving means, a process for calculating the position of the moving body is executed,
    In the transmission of the ultrasonic signal from the transmission device, a pseudo-random signal that differs for each transmission cycle is used.
  35. 　前記擬似ランダム信号がＭ系列であることを特徴とする請求項３４に記載の位置検出プログラム。 The position detection program according to claim 34, wherein the pseudo-random signal is an M series.
  36. 　前記送信装置を構成するコンピュータが、
    　互いに異なる複数のＭ系列から選択した任意のＭ系列を規定するデータに基づき生成されたＭ系列データによって変調された超音波信号と、前記Ｍ系列を規定するデータを含む電磁波信号を送出することを特徴とする請求項３５に記載の位置検出プログラム。     A computer constituting the transmitting device is
    Transmitting an ultrasonic signal modulated by M-sequence data generated based on data defining an arbitrary M-sequence selected from a plurality of different M-sequences, and an electromagnetic wave signal including the data defining the M-sequence 36. The position detection program according to claim 35, wherein:
  37. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列初期条件データであることを特徴とする請求項３５又は請求項３６に記載の位置検出プログラム。 37. The position detection program according to claim 35, wherein the data defining the M series included in the electromagnetic wave signal is M series initial condition data.
  38. 　前記電磁波信号が含むＭ系列を規定するデータが、Ｍ系列の特性多項式と初期条件データとあることを特徴とする請求項３５又は請求項３６に記載の位置検出プログラム。 37. The position detection program according to claim 35, wherein the data defining the M series included in the electromagnetic wave signal includes an M series characteristic polynomial and initial condition data.
  39. 　前記超音波信号をＭ系列データにより位相変調することを特徴とする請求項３５から請求項３８の何れかに記載の位置検出方法。 The position detection method according to any one of claims 35 to 38, wherein the ultrasonic signal is phase-modulated with M-sequence data.
  40. 　前記電磁波信号として赤外線を送信することを特徴とする請求項３４から請求項３９の何れかに記載の位置検出プログラム。 40. The position detection program according to claim 34, wherein infrared rays are transmitted as the electromagnetic wave signal.
  41. 　前記移動体が電子ペンであることを特徴とする請求項３４から請求項４０の何れかに記載の位置検出プログラム。 41. The position detection program according to claim 34, wherein the moving body is an electronic pen.
  42. 　前記移動体がロボットであることを特徴とする請求項３４から請求項４０の何れかに記載の位置検出プログラム。 41. The position detection program according to claim 34, wherein the moving body is a robot.
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