JP2013217754A - Distance measuring device and distance correction means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distance measuring device and distance correction means that are capable of measuring a distance with high accuracy.SOLUTION: First transmitting and receiving means 101a intermittently transmits a radio signal including at least a start point signal, and when second transmitting and receiving means 101b receives the radio signal, the second transmitting and receiving means 101b demodulates the start point signal from the received radio signal, corrects an inherent propagation delay error by an inexpensive method, and then transmits, by return, the radio signal including a distance measuring signal synchronized with the demodulated and corrected start point signal, in time division timing. The first transmitting and receiving means demodulates the distance measuring signal received from the second transmitting and receiving means, corrects the inherent propagation delay error by the inexpensive method, and then calculates a distance between the first and second transmitting and receiving means with high accuracy by measuring a propagation delay phase or propagation delay time of the distance measuring signal corrected on the basis of the start point signal generated at a self station.

Description

According to the present invention, the distance between each other is accurately determined by performing communication between the first transmitting / receiving unit and the second transmitting / receiving unit using a single radio frequency in a time division manner. It is related with the distance measuring device and distance correction | amendment means which can be measured by.

Conventionally, there has been proposed a distance measuring device having a distance correcting means for performing mutual communication between a plurality of wireless communication devices and measuring a distance between them. (For example, see Patent Documents 1 to 3)
Japanese Patent Application No. 2011-253633 JP 2009-162488 A JP 2001-033543 A

8 and 9 show an example of the conventional “distance measuring device and distance correcting means” described in Patent Document 1, in which distance correcting means 52 is provided in the first and second control means, and radio wave attenuation is performed. Correction coefficient stored at the time of shipment or at a timely timing using RSSI values obtained by measuring received signal strengths to the first and second receiving means 13a and 13b in order to prevent a decrease in distance measurement accuracy at the time Is used to correct the distance.
On the other hand, in the example of the conventional “wireless terminal apparatus and gain adjustment method” described in Patent Document 2, the distance due to radio wave attenuation is obtained by matching the signal levels of the transmission signal and the reception signal when measuring the round-trip time. It is configured to prevent a decrease in measurement accuracy.

On the other hand, in the embodiment of the conventional “distance detection method and distance detection device” described in Patent Document 3, the signal delay time in the transmission / reception system circuit is measured using the measurement distance obtained by directly receiving the transmission / reception signal. However, the actual correction value should be changed according to the received signal strength.
As described above, the conventional means for preventing the decrease in distance measurement accuracy corrects the distance measurement error caused by the fluctuation of the propagation delay time of the intermediate frequency amplifier due to the fluctuation of the received signal strength to the receiver. In order to maintain the specified distance measurement accuracy despite the complexity and cost of the device, detailed temperature compensation or aging correction is performed. There was a problem such as necessity.

The present invention has been made to solve the above-described problems, and uses a single radio frequency between the first transmitting / receiving means and the second transmitting / receiving means in a time division manner. By providing communication, it is possible to provide a distance measurement device and distance correction means that can measure the distance between each other with high accuracy and in a short time at low cost and without requiring temperature compensation or aging correction. Objective.

  In the distance measuring apparatus according to the present invention, the first transmitting / receiving unit intermittently transmits a radio signal including a starting point signal as a burst signal to the second transmitting / receiving unit, and the second transmitting / receiving unit. When receiving a radio signal including a starting signal transmitted from the first transmitting / receiving unit, a radio signal including a distance measurement signal synchronized with the received starting signal with high accuracy is transmitted to the first transmitting / receiving unit. In response, the first transmission / reception unit receives a radio signal transmitted from the second transmission / reception unit, and transmits at a time division timing selected at random from a plurality of time slots. Demodulating the distance measurement signal, measuring a propagation delay phase difference or a propagation delay time difference of the demodulated distance measurement signal using a clock signal synchronized with the origin signal generated by the own station, and performing the first transmission / reception The distance between the stage and the second place and receive means is configured to measure at high accuracy.

In order for a conventional distance measuring device to measure a distance with high accuracy, an "error detecting / correcting means" is provided in the receiving means and the control means of the transmitting / receiving means, and the propagation delay of the intermediate frequency amplifier is caused by fluctuations in the received signal intensity. In contrast to the fact that the time fluctuates, the correction value and correction coefficient corresponding to the received signal strength are stored at the time of shipment, and the correction of the distance is performed using the stored correction value and correction coefficient. The distance measurement device employs a "low propagation delay amplification / demodulation means" so that the fluctuation of the propagation delay time of the intermediate frequency amplifier becomes sufficiently small with respect to the fluctuation of the received signal strength. It is possible to delete the “error detection / correction means” having a simple configuration, and a highly accurate distance measuring device can be realized at low cost.

Thus, in the distance measuring device of the present invention, by performing communication between the first transmitting / receiving unit and the second transmitting / receiving unit by a burst signal using a single radio frequency, There is an advantage that the distance between each other can be calculated in a short time and with high accuracy by an inexpensive apparatus.

The block diagram of the distance measuring device by the 1st Embodiment of this invention The block diagram of the 1st transmission / reception means by the 1st Embodiment of this invention The block diagram of the 2nd transmission / reception means by the 1st Embodiment of this invention Timing chart according to the first embodiment of the present invention Control flowchart according to the first embodiment of the present invention Configuration diagram of synchronization establishment / holding means according to the first embodiment of the present invention The block diagram of the distance measurement means by the 1st Embodiment of this invention Configuration diagram showing a conventional example Configuration diagram showing another conventional example

  As shown in FIGS. 1 to 5 and claim 1 of the first embodiment of the present invention, the distance measuring apparatus according to the present invention uses a radio signal to transmit the first transmitter / receiver and the second transmitter. In the distance measuring device for measuring the distance to the receiving means, the first transmitting / receiving means intermittently transmits the wireless signal as a burst signal at a time division timing, and the wireless A first receiving means for receiving a signal at time-division timing, a first control means for controlling the first sending means and the first receiving means, and the first sending means; The first antenna switching means for switching or sharing the antenna in a time division manner with the first receiving means.

The second transmitting / receiving means transmits the radio signal intermittently as a burst signal at time division timing, and the second reception for receiving the radio signal at time division timing. Means, a second control means for controlling the second transmitting means and the second receiving means, and an antenna in a time-sharing manner between the second transmitting means and the second receiving means. It comprises second antenna switching means for switching or sharing.
In the first transmitting / receiving means, the first receiving means includes at least a first low noise amplifier, a first mixer, a first intermediate frequency filter, and a first low propagation delay amplification / demodulation. And the first control means includes at least a first synchronization establishment / holding means, a first distance measuring means, and a first starting point signal generating means.

  In the second transmitting / receiving means, the second receiving means includes at least a second low noise amplifier, a second mixer, a second intermediate frequency filter, and a second low propagation delay amplification / demodulation. And the second control means includes at least a second synchronization establishment / holding means and a distance measurement signal generation means, and the first and second transmission means and reception means total. The propagation delay time of the first and second intermediate frequency filters is 10 nanoseconds or less, and the propagation of the first and second low propagation amplification / demodulation means The delay time is 5 nanoseconds or less, and in the first, second, or both control means, the fluctuation of the received signal strength to the first, second, or both reception means, Comparison of fluctuations in the propagation delay time And it performs fixedly distance corrected for less constant part.

According to a second aspect of the present invention, the origin signal and the distance measurement signal are ASK modulated or amplitude modulated, and the low propagation delay amplifying / demodulating means includes a wideband differential amplifying means, an automatic gain control means, a hysteresis characteristic. , Broadband comparator, or a combination thereof.
According to another aspect of the present invention, the received signal strength to the receiving means fluctuates, whereas the fluctuation portion where the propagation delay time of the receiving means fluctuates is within 2 nanoseconds.
According to a fourth aspect of the present invention, the intermediate frequency filter is formed of a passive circuit and has an equivalent bandwidth of 100 MHz or more, and the low propagation delay amplification / demodulation means includes at least a high speed differential amplifier, a high speed The operational amplifier, the high-speed comparator, or a combination thereof, and the equivalent bandwidth is 200 MHz or more.

In addition, according to a fifth aspect of the present invention, the synchronization establishment / holding means detects a rising point, a falling point, or a zero crossing point of the demodulated origin signal or distance measurement signal by a sampling signal having a high frequency of 1 GHz or more. At the detected timing, synchronization is established and maintained by setting or resetting a single or a plurality of counters.
Further, according to a sixth aspect of the present invention, the distance measuring unit includes a comparing unit that compares the output signal of the synchronization establishing / holding unit and the output signal of the starting point signal generating unit, and both of the comparison results. Detecting means for detecting periods in which the sign or phase is the same or different, distance calculating means for calculating a relative distance between them from the same or different period, and distance correction for the constant portion. And a distance correction means for performing.

Further, as shown in claim 7, when the second transmitting / receiving unit receives a radio signal including a starting signal and an identification signal transmitted from the first transmitting / receiving unit, the received starting signal and A radio signal including a distance measurement signal and an identification signal synchronized with high accuracy is sent back to the first transmitting / receiving unit at a time division timing randomly selected from a plurality of time slots.
Moreover, as shown in claim 8, the radio signal is an electromagnetic wave signal in a millimeter wave band.
Further, as shown in claim 9, the first transmission / reception means, the second transmission / reception means, or both of them have a function as a millimeter wave radar.

(Embodiment 1)
FIG. 1 is a configuration diagram of a distance measuring apparatus according to a first embodiment of the present invention. In FIG. 1, 101a is a first transmission / reception means, 101b is a second transmission / reception means, 11a and 11b are control means, 12a and 12b are transmission means, 13a and 13b are reception means, and 14a and 14b are antenna switching means. , 15a and 15b are antennas, and 16 is a propagation path of a radio signal. The first transmitting / receiving unit 101a and the second transmitting / receiving unit 101b use a radio signal of a single frequency such as a 40 GHz band, and perform bidirectional communication via the propagation path 16 by time division simultaneous communication. The relative distance between each other can be measured with high accuracy.

It is assumed that the first transmitting / receiving unit, the second transmitting / receiving unit, or both of these antennas are high-gain directional antennas and are installed facing each other.
Also, in the 40 GHz band, 2 kW is allowed as the equivalent isotropic radiant power. If the distance between the first transmitter / receiver and the second transmitter / receiver is a line-of-sight, mutual communication is possible even at a distance of 300 m or more. And has the advantage that it is not affected by rain, fog, or snow.

  FIG. 2 is a block diagram of the first transmitting / receiving means according to the first embodiment of the present invention. In FIG. 2, 101a is the first transmission / reception means, 11a is the first control means, 12a is the first transmission means, 13a is the first reception means, 14a is the first antenna switching means, and 15a is the first , 41 is an input / output terminal of the first antenna switching means, 42 is an input terminal to the first receiving means, 43 is a low noise amplifier, 44 is a mixer, 45 is a local signal oscillator, and 46 is an intermediate Frequency filter 71: Low propagation delay amplification / demodulation means 50a, 50d: connection terminals 51: first synchronization establishment / holding means 53: distance calculation means 54: origin signal generation means 54: modulation / amplification means 55 , 56 is a roll-off filter, 57 is a mixer, 58 is a power amplifier, 59 is an output terminal of the first transmitting means, and 60 is a distance measurement output terminal.

  The starting signal generating means 54 of the first control means 11a is intermittently activated to generate an identification signal and a starting signal, input to the modulation / amplifying means 55 via the connection terminal 50d, and modulated and then specified. The output is amplified, the band is limited by the roll-off filter 56, mixed with the output of the local oscillator 45 by the mixer 57, amplified to the specified power by the power amplifier 58, switched by the antenna switching means 14a, and at least from the antenna 15a. The signal is radiated into space as a radio signal including the origin signal.

  On the other hand, a radio signal including at least a distance measurement signal radiated from the second transmitting / receiving unit 11b to the space is received by the antenna 15a, switched by the antenna switching unit 14a, and input to the connection terminal 42. Amplified by the noise amplifier 42, mixed with the output signal of the local oscillator 45 by the mixer 44, converted into an intermediate frequency signal, selected by the intermediate frequency filter 46, and then amplified by the low propagation delay amplification / demodulation means 71. The distance measurement signal is demodulated, and synchronization with the distance measurement signal is established and held by the synchronization establishment / holding means 51 of the first control means 11a via the connection terminal 50a, and the held distance measurement signal is held. The delay phase or the delay time is determined based on the origin signal generated by the origin signal generating means 54. Measured by the measuring means 53, the distance between the second place and receive unit 101 is measured with high accuracy, and transfers the measurement result via the connection terminal 60 to an external display device (not claimed).

  The main elements that cause a propagation delay in the first receiving means 13a are the intermediate frequency filter 46, the low propagation delay amplifying / demodulating means 71, and other electronic components. The propagation delay caused by the intermediate frequency filter 46 is less affected by fluctuations in the received signal intensity and exhibits a substantially constant value. On the other hand, the low propagation delay amplification / demodulation means 71 has a propagation delay time. If a signal having a small absolute value can be realized, the fluctuation of the propagation delay time is sufficiently small with respect to the fluctuation of the received signal strength, and therefore the distance measurement error is small and the distance measurement accuracy can be increased.

  The low propagation delay amplifying / demodulating means 71 can realize a wide band of about 10 GHz or more as an equivalent bandwidth by using an ultra high speed differential amplifier, an ultra high speed operational amplifier, an ultra high speed comparator, or a combination thereof. Since the absolute value of the delay time is 100 picoseconds or less and is a small fluctuation of about 30 picoseconds with respect to the fluctuation of the received signal strength, on the other hand, a fixed part of about 70 picoseconds can be realized. The distance measurement error can be suppressed to about ± 15 cm by correcting the fixed value portion that does not vary with the variation of the received signal intensity together with the propagation delay time of the filter 46.

The propagation delay time of the first and second intermediate frequency filters is 10 nanoseconds or less, and the propagation delay time of the first and second low propagation delay amplification / demodulation means is 5 nanoseconds or less. In the first, second, or both of the control means, the distance of a constant portion of the propagation delay time that is less fluctuating with respect to fluctuations in received signal strength to the first and second receiving means. Correction shall be performed.
Further, the origin signal and the distance measurement signal are ASK-modulated, and the propagation delay fluctuation can be ignored with respect to the change of the received signal strength by widening the equivalent bandwidth of the low propagation delay amplification / demodulation means. Can be reduced to a degree.

  In addition, while the received signal strength to the receiving unit varies, the fluctuation part in which the propagation delay time of the receiving unit varies is within 2 nanoseconds, the intermediate frequency filter is configured by a passive circuit, and the low It is assumed that the propagation delay amplification / demodulation means includes at least a high-speed differential amplifier, a high-speed operational amplifier, a high-speed comparator, or a combination thereof.

In addition, there are also propagation delays in the low noise amplifier 43, the mixer 44, etc., all of which have an equivalent bandwidth of 1 GHz or more. Can be made small enough to be ignored.
In the first control means, the second control means, or both synchronization establishment / holding means, the demodulated origin signal or the zero crossing point of the distance measurement signal is detected by a high frequency sampling signal of 1 GHz or more. By detecting or dividing the sampling signal to generate a distance measurement signal, a single or a plurality of counters are set or reset at the timing of the zero crossing point, so that the distance measurement error caused by the synchronization error is ± It can be reduced to 15 cm or less.

  FIG. 3 is a block diagram of the second transmitting / receiving means according to the first embodiment of the present invention. In FIG. 3, 101b is the second transmitting / receiving means, 11b is the second control means, 12b is the second transmitting means, 13b is the second receiving means, 14b is the second antenna switching means, and 15b is the antenna. , 41 is an input / output terminal of the second antenna switching means, 42 is an input terminal to the second receiving means, 43 is a low noise amplifier, 44 is a mixer, 45 is a local signal oscillator, and 46 is an intermediate frequency filter. , 47 is a low propagation delay amplification / demodulation means, 50a and 50d are connection terminals, 51 is a second synchronization establishment / holding means, 61 is a distance measurement signal generation means, 55 is a modulation / amplification means, 56 is a roll-off filter, 57 is a mixer, 58 is a power amplifier, and 59 is an output terminal of the second transmitting means.

  When a radio signal including an origin signal radiated from the first transmitting / receiving unit 11a to the space is received by the antenna 15b, switched by the antenna switching unit 14b, and input to the connection terminal 42, the low-noise amplifier 42 The signal is amplified and mixed with the output of the local oscillator 45 by the mixer 44 to be converted to an intermediate frequency signal. After being selected by the intermediate frequency filter 46, the signal is amplified by the low propagation delay amplification / demodulation means 71 and the starting signal is Demodulated and synchronized with the origin signal by establishing and holding the synchronization with the origin signal by the synchronization establishment / holding means 51 of the second control means 11b via the connection terminal 50a, and synchronized with the phase or delay time of the origin signal held in synchronization. The distance measurement signal generated is generated by the distance measurement signal generation means 61, and the generated distance measurement signal is connected to the connection terminal 5 Transferred to the second transmitting unit 12b through d.

  The distance measurement signal generation means 61 of the second control means 11b is activated at a time division timing to generate an identification signal and a distance measurement signal, which are input to the modulation / amplification means 55 via the connection terminal 50d and modulated. After being amplified to a specified output, the band is limited by the roll-off filter 56, mixed with the output of the local oscillator 45 by the mixer 57, amplified to a specified power by the power amplifier 58, and switched by the antenna switching means 14b. And is radiated to the space from the antenna 15b.

  The main elements that generate the propagation delay time in the second receiving means 13b are the intermediate frequency filter 46 having a relatively narrow band and the low propagation delay amplifying / demodulating means 71. The propagation delay caused by the intermediate frequency filter 46 is less affected by fluctuations in the received signal intensity and exhibits a substantially constant value. On the other hand, the low propagation delay amplification / demodulation means 71 has a propagation delay time. By reducing the absolute value of the signal to 1 nanosecond or less, the fluctuation of the propagation delay time is also reduced with respect to the fluctuation of the received signal strength. it can.

  The low propagation delay amplifying / demodulating means 71 is a combination of an ultra high speed differential amplifier, an ultra high speed operational amplifier, an ultra high speed comparator or the like, and an equivalent bandwidth of about 10 GHz or more can be realized. If the absolute value can be 100 picoseconds or less and the fluctuation of the received signal intensity is about 30 picoseconds, the fixed part is about 70 picoseconds, and the propagation delay time of the intermediate frequency filter 46 is increased. The distance measurement error can be suppressed to about 1 cm by correcting the fixed value portion that does not vary with respect to the variation in the received signal strength. If the bandwidth of the intermediate frequency filter 46 can be 1 GHz, the propagation delay time is 1 nanosecond, which can be improved to a delay equivalent to 30 cm.

  It should be noted that the propagation delay time of the first and second transmitting means and the receiving means is about 20 nanoseconds or less, and the propagation delay times of the first and second intermediate frequency filters are acceptable in practice. The propagation delay time of the first and second low propagation delay amplification / demodulation means is about 5 nanoseconds or less.

In addition, there are propagation delays in the low-noise amplifier 43, the mixer 44, etc., but all are small enough to be ignored.
Further, the first control means, the second control means, or both of them have synchronization establishment / holding means, and the rising edge, falling edge, or zero crossing point of the demodulated origin signal or distance measurement signal is high. A highly accurate synchronization is achieved by setting or resetting a counter with reset to detect a frequency sampling signal and divide a reference signal with high frequency stability to generate a distance measurement signal at the detected timing. Since the synchronization can be stably maintained even after the origin signal disappears, the distance measurement error caused by the synchronization error can be reduced.

  FIG. 4 is a timing chart of the distance measuring apparatus according to the first embodiment of the present invention. In FIG. 4, 21a is a starting signal transmitted from the first transmitting / receiving means 101a, 21b is a starting signal demodulated by the second transmitting / receiving means 101b, and 22 is a second transmitting signal from the first transmitting / receiving means. A propagation path through which the origin signal propagates toward the reception means, 23a is a distance measurement signal generated in synchronization with the origin signal demodulated by the second origination / reception means, and 23b is demodulated by the first origination / reception means The distance measurement signal 24 is a propagation path through which the distance measurement signal propagates from the second transmission / reception means toward the first transmission / reception means.

On the other hand, 25 is a time-division interval from the transmission timing of the first transmission / reception means to the transmission timing of the second transmission / reception means, and 26 is the origin signal transmitted from the first transmission / reception means and the A phase difference from the distance measurement signal demodulated by the first transmitter / receiver; 27a, a time axis of the transmitter of the first transmitter / receiver; 27b, a time axis of the receiver of the first transmitter / receiver; 28a is the time axis of the receiving means of the second transmitting / receiving means, and 28b is the time axis of the transmitting means of the second transmitting / receiving means.
Alternatively, by providing a plurality of time slots with respect to the time division interval 25 and selecting and randomly turning back, a merit that distances between the plurality of second transmitting / receiving units can be measured can be obtained.

Assuming that the starting signal 21a transmitted from the first transmitting / receiving means is ASin (2πf1t), the starting signal 21a propagates through the propagation path 22 of the distance L (m) and is transmitted by the second transmitting / receiving means. When received and demodulated as the origin signal 21b, the phase changes to BSin {2πf1t + (2πLf1 / C)}.
When the distance measurement signal 23a synchronized with the demodulated starting point signal 21b is generated, the generated distance measurement signal 23a is also represented by BSin {2πf1t + (2πLf1 / C)}.

After the time division interval 25, the generated distance measurement signal 23a is transmitted from the second transmission / reception means, propagates again through the propagation path 16 of the distance L (m), and the first transmission signal is transmitted. The distance measurement signal 23b demodulated by the receiving means is represented by CSin {2πf1t + (4πLf1 / C)}. Here, C is the speed of light.
Therefore, when the phase of the demodulated distance measurement signal 23b is measured using a clock signal that is synchronized with or orthogonal to the starting signal 21a generated by the first transmitting / receiving means and whose frequency is an integral multiple of the starting signal. The phase difference 26 between the starting point signal 21a generated by the first transmitter / receiver and the distance measurement signal 23b demodulated by the first transmitter / receiver is measured, and ΔΦ = {4πLf1 / C}. From L = {CΔΦ / 4πf1}, the distance L (m) can be calculated.

In the distance measurement, the same effect can be obtained by measuring the propagation delay time difference instead of measuring the propagation phase difference.
Further, in the calculated distance, a distance measurement error occurs due to a propagation delay inherent in the transmission / reception means. Therefore, it is necessary to provide an appropriate distance correction means.
In addition, since it is difficult to correct the distance of the existing propagation delay where the propagation delay fluctuates due to a change in received signal strength, an inexpensive distance correction means can be realized by keeping the absolute value as small as possible.

FIG. 5 is a control flowchart according to the first embodiment of the present invention. In FIG. 5, 31 is a start, 32 is a control step of the first transmission / reception means, 33 is a control step of the second transmission / reception means, 34 is a control step of the first transmission / reception means, and 35 is END.
In the control step 32 of the first transmission / reception means, the first transmission / reception means generates a starting point signal, intermittently transmits a radio signal including the starting point signal, and the second transmission / reception means control step 33 receives the signal. The origin signal is demodulated from the radio signal by the low propagation delay amplification / demodulation means to detect and hold the synchronization, and the distance measurement signal synchronized with the held origin signal is generated, and the radio signal including the distance measurement signal is transmitted to a plurality of times. Call back at a time-sharing timing randomly selected from the slot.

Further, in the control step 34 of the first transmission / reception means, the origin signal is demodulated from the received radio signal by the low propagation delay amplification / demodulation means to detect and hold the synchronization, and the origin signal that is transmitted first is used as a reference. The delay phase or delay time of the held distance measurement signal is measured, and the distance is calculated by correcting a fixed portion where the fluctuation of the propagation delay time is small with respect to the fluctuation of the received signal strength inherent in the receiving means.
As means for establishing synchronization instantaneously and maintaining synchronization for a long time, a synchronization detection / holding means 51 shown in FIG. 6 is provided.

FIG. 6 is a block diagram of the synchronization establishment / holding means according to the first embodiment of the present invention. In FIG. 6, 51 is synchronization establishment / holding means, 61 is a distance measurement signal generation means, 71 is a low propagation delay amplification / demodulation means, 81 is a reference oscillator, 82 is a counter with reset, 83 is a phase synchronization oscillator, and 84 is synchronization. Detection means 50a and 86 are connection terminals.
By providing a plurality of sets of the reset counter 82, synchronization is established and held at a plurality of timings, distance measurement is performed corresponding to the plurality of timings, and an average value of a plurality of measurement values is taken. The distance measurement accuracy can be improved.

The low propagation delay amplification / demodulation means 71 outputs a demodulated starting signal via the connection terminal 50a, generates a high frequency sampling signal of about 200 MHz or more by the phase-locked oscillator 83, and uses the sampling signal. The synchronous detection means 84 detects the rising point, the falling point, or the zero crossing point of the demodulated starting point signal, sets or resets the counter 82, and the distance measurement signal generation means 61 generates the distance measurement signal synchronized with the starting point signal. To supply. Therefore, the distance measurement signal can hold a frequency having the same stability as that of the reference oscillator 81 for a long time after the origin signal disappears.

  FIG. 7 is a block diagram of the distance measuring means according to the first embodiment of the present invention. In FIG. 7, 53 is a distance measuring means, 51 is synchronization establishment / holding means, 54 is a starting point signal generating means, 83 is a phase synchronous oscillator, 91 is comparison means (XOR logic), 92 is a gate circuit (AND logic), 93 Is a detection means (binary counter), 94 is a distance calculation / correction means (CPU), and 96 and 60 are connection terminals.

In the comparing means (XOR logic) 91, the distance measurement signal held by the synchronization establishing / holding means 51 is compared with the starting signal generated by the starting signal generating means 54. A gate circuit (AND logic) 92 is provided in order to prevent the pulse signal from passing through and to pass the pulse signal from the phase-locked oscillator 83 toward the detection means (binary counter) 93 when the two do not match.
That is, in the comparison means 91, the pulse signal from the phase-locked oscillator 83 is blocked by the gate circuit 92 when the two match, and when the two do not match, the pulse signal is passed.
Therefore, when the two do not match, the binary counter 93 is swung by the output pulse of the phase-locked oscillator 83, the number of pulses is read by the CPU 94, the distance between the two is calculated, and distance correction is performed for the constant portion.

Since the number of read pulse signals can measure the total propagation delay time of the propagation delay time inherent in the first transceiver and the second transceiver, and the propagation delay time caused by the distance between the two, The total propagation delay time minus the constant or fixed part of the propagation delay time inherent in the transceiver is calculated as the propagation delay time proportional to the distance between them, and the corrected distance between them is measured. it can.
Of the propagation delay times inherent in the transceiver, those affected by fluctuations in received signal strength are kept as small as possible by widening the equivalent bandwidth, and a fixed one that is not affected by received signal strength is subtracted as a distance correction value. Thus, the distance measurement accuracy can be improved.

  In the above description, the transmitting / receiving means uses a radio signal having a relatively wide frequency band, adopts a circuit configuration in which the fluctuation of the propagation delay time is small with respect to the fluctuation of the received signal intensity, or the fluctuation of the received signal intensity. On the other hand, a method for correcting a constant portion with a small variation in propagation delay time has been described. For this purpose, an electromagnetic wave signal or an optical signal in a millimeter wave band of 30 GHz band or higher that can occupy a wide bandwidth is used as a radio signal. It is desirable.

Further, among the circuit configurations of the transmitting and receiving means, the influence of an intermediate frequency filter, a roll-off filter, or other electronic components having a large propagation delay time is large, so that the equivalent pass bandwidth is increased as much as possible, It is necessary to reduce the propagation delay time.
In addition to the function of measuring the distance by mutual communication, the first transmitting / receiving means, the second transmitting / receiving means, or both of them, a conventional millimeter wave radar (detects a reflected wave to detect the distance). Add or share the function of (measurement), it becomes possible to have a double distance measurement means, the merit that can improve the reliability, and either one has a mutual communication function Even if it is not, it is possible to measure the distance to the other party.

According to the present invention, a high-accuracy and inexpensive apparatus can be obtained in a short time by performing intercommunication at a time division timing randomly selected from a plurality of time slots between a plurality of transmission / reception means. It becomes possible to measure the distance between each other with high accuracy.
For example, the distance and direction between cars traveling on a highway can be measured instantaneously and with high accuracy, and can be applied to cooperative driving or collision prevention devices, or to pedestrians or robots, etc. Autonomous movement can be guided or controlled.
Note that the distance measurement technique of the present invention is a basic technique, and can be expected to be used in many other fields.

101a First transmission / reception means 101b Second transmission / reception means 11a, 11b Control means 12a, 12b Transmission means 13a, 13b Reception means 14a, 14b Antenna switching means 15a, 15b Antenna

Claims (9)

In a distance measuring device that measures a distance between a first transmitting / receiving unit and a second transmitting / receiving unit using a radio signal,
A first transmission means for intermittently transmitting the radio signal as a burst signal at a time division timing; and a first reception for receiving the radio signal at a time division timing. Means, a first control means for controlling the first transmitting means and the first receiving means, and an antenna in a time-sharing manner between the first transmitting means and the first receiving means. A first antenna switching means for switching or sharing,
The second transmitting / receiving means transmits the radio signal intermittently as a burst signal at time division timing, and the second reception for receiving the radio signal at time division timing. Means, a second control means for controlling the second transmitting means and the second receiving means, and an antenna in a time-sharing manner between the second transmitting means and the second receiving means. A second antenna switching means for switching or sharing,
In the first transmitting / receiving means, the first receiving means includes at least a first low noise amplifier, a first mixer, a first intermediate frequency filter, and a first low propagation delay amplification / demodulation. And the first control means includes at least a first synchronization establishment holding means, a first distance measuring means, and a first starting point signal generating means,
In the second transmitting / receiving means, the second receiving means includes at least a second low noise amplifier, a second mixer, a second intermediate frequency filter, and a second low propagation delay amplification / demodulation. And the second control means includes at least a second synchronization establishment holding means and a second distance measurement signal generating means,
The total propagation delay time of the first and second transmission means and reception means is 20 nanoseconds or less, the propagation delay time of the first and second intermediate frequency filters is 10 nanoseconds or less, and the first The propagation delay time of the first and second low propagation delay amplifying / demodulating means is 5 nanoseconds or less, and the first, second, or both of the control means, the first, second, or these A distance measuring device and a distance correcting means characterized in that distance correction is performed on a constant portion where the fluctuation of the propagation delay time is relatively small with respect to fluctuations in received signal strength to both receiving means.
In the first aspect, the origin signal and the distance measurement signal are ASK-modulated, and the low propagation delay amplification / demodulation means includes a wideband differential amplification means, an automatic gain control means, a hysteresis characteristic, a wideband comparator, or A distance measuring device and a distance correcting means characterized by having a combination thereof.
2. The distance measuring apparatus according to claim 1, wherein the received signal strength to the receiving means varies, but the fluctuation portion where the propagation delay time of the receiving means varies is within 2 nanoseconds. And distance correction means.
2. The method of claim 1, wherein the intermediate frequency filter is formed of a passive circuit and has an equivalent bandwidth of 100 MHz or more, and the low propagation delay amplification / demodulation means includes at least a high-speed differential amplifier and a high-speed operational amplifier. A distance measuring device and a distance correcting means, characterized in that it is constituted by a high-speed comparator, or a combination thereof, and has an equivalent bandwidth of 200 MHz or more.
In the first aspect, the synchronization establishment / holding means detects a rising point, a falling point, or a zero crossing point of the demodulated starting point signal or distance measurement signal by a sampling signal having a high frequency of 200 MHz or more, A distance measuring device and distance correcting means for establishing and maintaining synchronization by setting or resetting a single or a plurality of counters at the detected timing.
The distance measuring means according to claim 1, wherein the distance measuring means compares the output signal of the synchronization establishing / holding means with the output signal of the origin signal generating means, and the sign of both of the comparison results. Alternatively, detection means for detecting periods with the same phase or different phases, distance calculation means for calculating a relative distance between the two with the same code or phase, or for correcting the distance for the constant portion A distance measuring device and a distance correcting means.
In the first aspect of the present invention, when the second transmitting / receiving unit receives a radio signal including the starting signal and the identification signal transmitted from the first transmitting / receiving unit, the received starting signal and the high accuracy A radio signal including a distance measurement signal and an identification signal synchronized with each other is sent back to the first transmission / reception means at a time division timing randomly selected from a plurality of time slots. Distance measuring device and distance correcting means.
2. The distance measuring apparatus and distance correcting means according to claim 1, wherein the wireless signal is an electromagnetic wave signal in a millimeter wave band.
  The distance measuring device and the distance correcting unit according to claim 1, wherein the first transmitting / receiving unit, the second transmitting / receiving unit, or both of them have a function as a millimeter wave radar. .

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