JPS5840148B2 - Sotsukiyokenyouparsutsuushinboshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a distance measuring system that can be applied to a communication system that has the ability to exchange information between vehicles and with a fixed station, which is necessary for safe driving of a car, and has the ability to detect the distance between vehicles and a preceding vehicle. This relates to a dual-purpose pulse communication method.

Conventionally, sensors for general vehicles have been developed to detect various conditions of their own forces, such as running speed and braking ability. Due to the lack of effective means, it has been difficult to develop an appropriate and fast-responsive driving assistance system that comprehensively judges information from each vehicle's sensors and information from fixed stations to ensure safe driving.

The present invention has been made in view of the above problems, and it transmits and receives information signals using pulse radio waves between an interrogator and a responder, and also converts the information signal from the interrogator into a coded pulse train. The first pulse radio wave of the interrogation radio wave consisting of a series of intermittent pulse radio waves pulse-modulated is used to send a response radio wave in response to the interrogation radio wave from the answering machine back to the interrogation machine, and the interrogation machine emits the interrogation radio wave. By measuring the elapsed time from the start point to the arrival point of the response radio wave and measuring the distance to the responder, information transmission by pulse communication and distance measurement by the secondary radar method can be performed simultaneously. It is possible to exchange information between relative units such as own army - leading vehicle, own vehicle - following vehicle, own vehicle - fixed station, etc., and also measure the relative distance at the same time, making it extremely effective for distance measurement when applied to driving assistance systems. The purpose is to provide a pulse communication method.

The present invention will first be described in detail with reference to an embodiment shown in the drawings.

In the schematic block diagram of FIG. 1, reference numeral 1 denotes a forward transmitter serving as an interrogation transmitter, which includes a first external code terminal 2 that applies an information signal and a first trigger terminal 3 that generates a measurement start trigger pulse. and emits interrogation radio waves A.

4 is a rear receiver that serves as a response receiver, and receives the interrogation radio wave A.

It has a fourth trigger terminal 5 that demodulates and generates a response trigger pulse, and a fifth trigger terminal 6 that generates a demodulated pulse train.

7 is an information reading circuit that is connected to the fourth trigger terminal 5 and the fifth trigger terminal 6 and generates a read information signal to the output terminal 8; 9 is a rear transmitter serving as a response transmitter; 4 and a second external code terminal 10, and emits a response radio wave B opposite to the arrival direction of the interrogation radio wave A.

Reference numeral 11 denotes a front receiver serving as an interrogation receiver, which has a second trigger terminal 12 that receives and demodulates the response radio wave B and generates a measurement end trigger pulse, and a third trigger terminal 13 that generates a demodulated pulse train. It is.

14 is the first trigger terminal 3 and the second trigger terminal 1
An information reading circuit 16 is connected to the first trigger terminal 3 and the second trigger terminal 12 and generates an information signal read to the output terminal 15; This is an inter-vehicle distance detection circuit that generates a measured inter-vehicle distance signal.

Next, in FIG. 2 showing a detailed block diagram of the forward transmitter 1, 18 is a clock pulse generator, 19 is connected to a parallel input terminal 21 connected to a high level voltage terminal 20, and a low level voltage terminal 22. This is a well-known parallel load shift register having a parallel input terminal 23 that connects the clock terminal to the clock pulse generator 18. It generates a rectangular signal whose time width changes sequentially.

24 is a known one-shot circuit connected to the output terminal of the shift register 19; 25 is the one-shot circuit 2;
4, a flip-flop circuit whose set terminal is connected to the output terminal 26 of the Nant gate 27, and a Q terminal connected to one input terminal of the Nant gate 27; and 28, a clock pulse generator connected to the other input terminal of the Nant gate 27; The clock pulse generator 18 generates a clock pulse having a frequency approximately 100 times higher than that of the clock pulse generator 18.

29 is a binary counter having a clock terminal connected to the output terminal of the Nant gate 27, a Q8 output terminal 30 connected to the reset terminal of the flip-flop circuit 25, and a preset terminal connected to the Q output terminal of the flip-flop circuit 25. A reference signal whose high and low levels are inverted every time eight clock pulses arrive is generated at the Q4 output terminal.

31 connects a parallel input terminal to the first external code terminal 2, and connects a clock terminal to the Q of the binary counter 29.
4 output terminal and a clear terminal connected to the Q output terminal of the flip-flop circuit 25, which converts the information signal of the first external code terminal 2 into a coded pulse train. .

32 is a one-shot circuit that is connected to the output terminal 35 of the shift register 31 and has a first trigger terminal 3; 33 is a one-shot circuit that connects the base terminal to the shift register 31 via a resistor 34;
a transistor connected to the output terminal 35, 36 a resistor,
37 is a positive voltage terminal, 38 is a control terminal 39 connected to the collector terminal of the transistor 33, a high frequency input terminal is connected to the microwave oscillator 40, and a high frequency output terminal is connected to the antenna 4.
1, which perform pulse modulation using the pulse train.

Next, in FIG. 3 showing a detailed block diagram of the rear receiver 4, 42 is an antenna, 43 is a microwave oscillator that oscillates at a frequency approximately 20 MHz higher than the oscillation frequency of the microwave oscillator 40, and 44 is the antenna 4
A mixer is connected to the microwave oscillator 43 and the microwave oscillator 43 to cause interference between the two signals, and its output signal is sent to the intermediate frequency amplifier 45.

46 is a detection circuit composed of a diode 48, a capacitor 49, and a resistor 50, and connected to the output terminal 47 of the intermediate frequency amplifier 45; 51 is composed of a capacitor 52, an inverter 53, and two Nandt gates 54 and 55; A comparator connected to the output terminal of the detection circuit 46 generates a demodulated pulse train at the fifth trigger terminal 6.

55 is composed of three inverters 56, 57, 58, three NAND games) 59, 60, 61, and a delay element 62, and a response trigger is sent to the fourth trigger terminal 5 from the demodulated pulse train of the output terminal of the comparator 51. This is a one-shot circuit that generates pulses.

Next, a fourth block diagram showing a detailed block diagram of the information reading circuit 7 is shown.
In the figure, 63 is a clock pulse generator that oscillates at the same frequency as the clock pulse generator 28, 64 is a Nant gate connected to the clock pulse generator 63, and 6
5 is a flip-flop circuit whose set terminal is connected to the fourth trigger terminal 5 and whose Q output terminal is connected to the input terminal of the Nantes gate 64; 66 is a binary counter whose clock terminal is connected to the output terminal of the Nantes gate 64; and connect the preset terminal to the Q of the flip-flop circuit 65.
When eight clock pulses arrive at the Q4 output terminal, a reference signal that inverts high and low levels is generated, and the Q8 output terminal is connected to the flip-flop circuit 65 via a delay element 65a. Connect to the reset terminal of the

67 is a known shift register that generates parallel output, and its clock terminal is connected to Q4 of the binary counter 66.
The clear terminal is connected to the Q output terminal of the flip-flop circuit 65, and the serial input terminal is connected to the fifth trigger terminal 6 to convert the demodulated pulse train into an information signal.

68 is a latch circuit whose clock terminal is connected to the Q8 output terminal of the binary counter 66, and whose input terminal is connected to the output terminal of the parallel output shift register 67;
The information signal is stored in the output terminal 8.

Next, in FIG. 5 showing a detailed block diagram of the rear transmitter 9, 69 is a clock pulse generator whose oscillation frequency is the same as that of the clock pulse generator 28.

70 is a Nandt gate whose one input terminal is connected to the clock pulse generator 69; 71 is a flip-flop whose set terminal is connected to the fourth trigger terminal 5 and whose Q output terminal is connected to the other input terminal of the Nandt gate 70; A loop circuit 72 connects the clock terminal to the output terminal of the Nantes gate 70;
A binary counter whose preset terminal is connected to the Q output terminal of the flip-flop circuit 71 generates a reference signal whose high and low levels are inverted every time a clock pulse is received at the Q4 output terminal.

73 connects the clock terminal to Q4 of the binary counter 72.
The clear terminal is connected to the output terminal of the flip-flop circuit 71, and the second external code terminal 1 is connected to the output terminal.
This is a soft register that applies an information signal to 0, and converts the information signal of the second external code terminal 10 into a coded pulse train.

74 is a transistor whose base terminal is connected to the output terminal 75 of the shift register 73 via a resistor 76; 78 is a positive voltage terminal which is connected to the collector terminal of the transistor 74 via a resistor 77; and 79 is a control terminal connected to the output terminal 75 of the shift register 73 via a resistor 76; This is a high frequency switch that is connected to the collector terminal of the transistor 74 and connects a high frequency input terminal and a high frequency output terminal to the microwave oscillator 80 and the antenna 81, respectively, and performs pulse modulation using the pulse train.

The oscillation frequency of the microwave oscillator 80 is set higher than the oscillation frequency of the microwave oscillator 40 by about 400 MHz.

Next, a sixth block diagram showing a detailed block diagram of the forward receiver 11 is shown.
In the figure, 83 is a microwave oscillator whose oscillation frequency is approximately 20 MHz higher than the oscillation frequency of the microwave oscillator 80, 84 is an antenna for receiving response radio waves, and 85
is an intermediate frequency amplifier, 86 is a mixer, 87 is a detector, 8
8 is a comparator, 89 is a one-shot circuit,
Each configuration has exactly the same configuration as the rear receiver 4 described above, and generates a measurement end trigger pulse at the second trigger terminal 12 and generates a demodulation pulse train at the third trigger terminal 13.

Next, in FIG. 7 showing a detailed block diagram of the information reading circuit 14, 132 is a Nant gate, 133 is an inverter, 90 is a clock pulse generator that oscillates at the same frequency as the clock pulse generator 69, and 91 is a Nant gate, 92 is a flip-flop circuit, 92a is a delay element,
93 is a binary counter, 94 is a parallel output shift register, and 95 is a latch circuit, each of which has the same configuration as the information reading circuit 7 described above, and converts the demodulated pulse train of the third trigger terminal 13 into an information signal. , and is stored in the output terminal 15.

Next, in FIG. 8 showing a detailed block diagram of the distance detection circuit 16, 97 is a clock pulse generator that generates clock pulses for time measurement.

98 is a Nant gate whose one input terminal is connected to the clock pulse generator 97; 99 is a Nant gate which connects the first trigger terminal 3 and the set terminal; and the Q output terminal is connected to the Nant gate 9.
a flip-flop circuit connected to the other input terminal of 8;
100 is a binary counter having a clock terminal 101 connected to the output terminal of the Nant gate 98 and a reset terminal connected to the Q output terminal of the flip-flop circuit 99;
102 is a latch circuit whose input terminal is connected to the output terminal of the binary counter 100 and whose clock terminal is connected to the second trigger terminal 12, and when a measurement end trigger pulse is generated at the second trigger terminal 12, The input signal is stored in the output terminal 17.

103 is a NOR gate that connects the Q8 output terminal of the binary counter 100 and one input terminal, 104 is a delay element interposed between the second trigger terminal 12 and the input terminal of the NOR gate 103, and 105 is a link between the NOR gate 103 and the flip-flop. This inverter is interposed between the four reset terminals of the reset circuit 99, and operates from the time when the measurement start trigger pulse is generated at the first trigger terminal 3 to the time when the measurement end trigger pulse is generated at the second trigger terminal 12. It measures the elapsed time.

Next, the operation of the above-mentioned intercept will be explained with reference to waveform diagrams of various parts in FIGS. 9 and 10.

First, in the forward transmitter 1 shown in FIG. 9), the output terminal of the parallel load shift register 19 is connected to the parallel input terminal 2.
17-bit logic “101100” given to 1 and 23
A rectangular signal (107 in FIG. 9) having a time interval and time width of 11000010100'' is generated.

This rectangular signal repeats every period 108. When this rectangular signal is applied to the one-shot circuit 24, FIG.
A trigger pulse of constant pulse width, illustrated at 9, is generated at terminal 26.

Since the same operation is repeated at each timing of the trigger pulse, the operation based on one trigger pulse will be explained with reference to the waveform diagram of each part in FIG. 10.

That is, the trigger pulse is applied to the flip-flop circuit 2.
5 is set, the Nant gate 27 passes the clock pulses of the clock pulse generator 28.

A clock pulse shown in FIG. 10 110 is applied to the clock input terminal of the binary counter 29, and a clock pulse shown in FIG.
The reference signal shown in is generated.

If the logic of the information signal to be sent to the space in front of the vehicle is 8 bits "11011101", this logic is applied to the first external code terminal 2.

Therefore, when the logic "11011101" is applied to the first external code terminal 2, the logic is converted into a pulse train (112 in FIG. 10) coded according to the reference signal and sent to the output terminal 35 of the parallel load shift register 31. begins to occur.

When the number of clock pulses arriving at the binary counter 29 reaches 128 indicated by the logic "10000000", a high level signal is generated at the Q8 output terminal, so that the flip-flop circuit 25 is reset.

Accordingly, the binary counter 29 is preset and stops counting since no clock pulse passes through the Nant gate 27.

At the same time, the parallel load shift register 31 is cleared and the generation of the pulse train from the output terminal 35 is stopped.

The pulse train generated at the terminal 35 is applied to the one-shot circuit 32, which generates one measurement start trigger pulse at the first trigger terminal 3 as shown in FIG. 10 113 in synchronization with the first pulse of the pulse train.

At the same time, the pulse train generated at the terminal 35 is transmitted to the base terminal of the transistor 33 via the resistor 34.

That is, when the voltage at the terminal 35 becomes high level, the transistor 33 becomes conductive, and the voltage at the control terminal 39 of the high frequency switch 38 becomes low level.

Therefore, the waves from the microwave oscillator 40 pass through the high frequency switch 38 and are emitted from the antenna 41 into the space in front of the vehicle.

Subsequently, when the voltage at the terminal 35 becomes low level, the transistor 33 becomes non-conductive and the microwave oscillator 40
The waves from the high frequency switch 38 are cut off by the high frequency switch 38.

By repeating this operation, an interrogation radio wave consisting of a series of intermittent pulse radio waves shown in FIG. 10 114 is emitted from the antenna 41 into the space in front of the vehicle.

This intermittent pulse radio wave is received by the rear receiver 4 of the preceding vehicle after a period of time proportional to the inter-vehicle distance has elapsed.

That is, the intermittent pulse radio waves are received by the antenna 42 in FIG.

This received wave is caused to interfere with the wave from the microwave oscillator 43 having an oscillation frequency approximately 200 MHz higher than the oscillation frequency of the microwave oscillator 40 by the mixer 44, resulting in an intermittent intermediate frequency signal as shown in FIG. 10 115. is converted to

The intermediate frequency signal 115 in FIG.
Then, a demodulated pulse train shown in FIG. 10 is generated.

On the other hand, a one-shot circuit 55 connected to the comparator 51 generates at the fourth trigger terminal 5 a response trigger pulse consisting of one one-shot pulse synchronized with the first pulse of the demodulated pulse train.

This response trigger pulse sets the flip-flop circuit 65 in the information reading circuit 7 of FIG.

This causes the clock pulse generator 6.3 to oscillate at the same frequency as the oscillation frequency of the clock pulse generator 28.
The clock pulses shown in FIG.

Therefore, as the logic of the binary counter 66 progresses, the reference signal (FIG. 10) whose high and low levels are inverted every time eight clock pulses arrive at the Q4 output terminal (see FIG.
) occurs, and this is the parallel output shift register 6γ
Ql of this parallel output shift register 67 because the demodulated pulse train shown in FIG. 10 from the fifth trigger terminal 6 is applied to the input terminal of the parallel output shift register 67.

Q2. Q3. Q4. Q5. Q6. 119 and 120° 121 in FIG. 10, respectively, to the output terminals Q7 and Q8.
．． Signals shown at 122, 123, 124, 125, and 126 begin to appear.

Then, at the moment when the output terminal of the binary counter 66 becomes the 8-bit logic "10000000"', that is, when eight pulses of the reference signal arrive at the clock terminal of the parallel output shift register 67, the output terminal becomes the 8-bit logic "10000000"'. It becomes "11011101".

At this time, the rising pulse shown in FIG. 10 is transmitted from the Q8 output terminal of the binary counter 66 to the clock terminal of the latch circuit 68, and the 8-bit logic "
An information signal '11011101' is stored, and the information signal sent from the forward transmitter 1 can be decoded and read.

Furthermore, since the rising pulse from the Q3 output terminal of the binary counter 66 resets the flip-flop circuit 65 via the delay element 65a, the binary counter 66 is again preset to its original state and waits for the arrival of the next response trigger pulse. It will be in a standby state for the accompanying operation.

On the other hand, the response trigger pulse (113 in FIG. 10) generated at the fourth trigger terminal 5 also arrives at the rear transmitter 9 in FIG. 5 and sets its flip-flop circuit 71.

As a result, the parallel load shift register 73 performs the same operation as that described for the forward transmitter 1 in FIG.
The response/information signal applied to the second external code terminal 10 of is converted into a coded pulse train and sent to the terminal 75.

That is, the first clock terminal of the binary counter 72 is
0 Figure 118: The clock pulse shown in the diagram is applied, and the second external code terminal 10 receives 8-bit logic "10000001".
If the response/information signal shown in FIG. 10 is applied to the terminal 75, the pulse train shown in FIG.
A response radio wave consisting of a series of intermittent pulse radio waves pulse-modulated according to the pulse train is reflected from the antenna 81 in a direction opposite to the arrival direction of the interrogation radio wave in the space behind the vehicle.

The intermittent pulse radio waves emitted in response are received by the forward receiver 11 of the following vehicle.

That is, the received wave is received by the antenna 84 in FIG. After that, the intermediate frequency amplifier 85, the detection circuit 87, and the comparator 88 generate the demodulated pulse train shown in FIG. Then, a measurement end trigger pulse shown in FIG. 10 131 is generated.

In the information reading circuit 14 of FIG. 7 to which the measurement end trigger pulse is applied, the third flip-flop circuit 92 is set in response to the measurement start trigger pulse already applied from the first trigger terminal 3. Trigger terminal 13
The demodulated pulse train is converted into an 8-bit logic response/information signal by the same operation as the information reading circuit 7 described above, and is stored in the output terminal 15 of the latch circuit 95 so as to be sent from the front space. 8-bit logic “1”
0000001'' response/information signal can be read.

On the other hand, the measurement end trigger pulse generated at the second trigger terminal 12 also arrives at the distance detection circuit 16 in FIG.
The measurement start trigger pulse from the first trigger terminal 3 is already transmitted to the clock terminal of the latch circuit 102 connected to the output terminal of the binary counter 100 that is counting the time measurement clock pulse from the clock pulse generator 97. and the binary counter 100 at that moment
The count value is stored in the output terminal 17.

At the same time, the flip-flop circuit 99 is reset after a delay determined by the delay element 104.

As a result, the output terminal of the binary counter 100 becomes a logic “
ooooooooo”.

The logical value stored in the output terminal 17 is the first
0 Indicates the number of clock pulses for time measurement from the rise of the measurement start trigger pulse in FIG. 113 to the rise of the measurement end trigger pulse in FIG. Therefore, the distance between vehicles can be determined from this stored logical value.The pulse communication operation of the distance measurement and information signal described above is performed by the trigger pulse shown in FIG. 9 at 109. It will be repeated at each occurrence timing.

The generation timing of the trigger pulse at this time is randomly changed according to a predetermined 17-bit logic, and the emission period of the interrogation radio wave emitted from the forward transmitter 1 of the interrogator is randomly changed. I can do it.

Therefore, by changing the above-mentioned 17-bit logic for each vehicle, the emission period of the interrogation radio waves of each vehicle will be different, and instead of the response radio waves in response to the interrogation radio waves emitted by the own army, the radio waves emitted by the oncoming vehicle will be used. The probability of erroneously receiving data becomes extremely small, increasing the reliability of the distance-measuring communication system.

According to the experiment accompanying the actual case mentioned above, the oscillation frequency of the microwave oscillator 40.80 for pulse modulation was approximately 10G.
Hz1 its output power 20 m W1 antenna 41,4
The opening area of 2, 81, and 82 is 5 crrL x 5 crf.
By setting it as L, good information transmission and reception and distance detection were possible with a distance between vehicles of 100 m.

In addition, although the above-mentioned actual case illustrated the transmission and reception of information between vehicles and the detection of the distance between vehicles, the present invention is not limited to this and can be similarly applied to, for example, between a vehicle and a fixed station.

Further, when transmitting a response/information signal from the rear transmitter 9 in the transponder, at least the first bit of the coded pulse train for pulse modulation may be set to a high level.

Furthermore, when obtaining a distance detection signal in meters at the output terminal 17 of the distance detection circuit 16, the oscillation frequency of the clock pulse generator 97 that generates the clock pulse for time measurement may be appropriately selected.

As described above, in the invention, an interrogator emits an interrogation radio wave consisting of a series of intermittent pulse radio waves pulse-modulated with a pulse train encoded with an information signal, and a responder that receives this interrogation radio wave receives and demodulates the interrogation radio wave. reads the information signal, and emits a response radio wave responsive to only the first pulse radio wave among the interrogation radio waves toward the interrogator, and the interrogator receives the response radio wave and emits the interrogation radio wave. Since the elapsed time from the start point to the arrival time of the response radio wave is measured, the distance between the interrogator and the responder can be measured by the secondary radar method with good responsiveness, and at the same time information can be transmitted by pulse communication. The interrogation radio waves can also be used for the interrogation radio waves, so if the interrogation device is mounted on the own army, information can be exchanged between the place where the answering device is installed and the relative distance can be measured at the same time. This has the excellent effect of being extremely effective when applied to driving assistance systems, etc.

Furthermore, since the interrogation radio waves emitted from the interrogator are randomly changed and emitted, the radio waves emitted from the interrogator of an oncoming vehicle etc. are recognized as response radio waves in response to the own interrogation radio waves and received. This has the excellent effect of greatly reducing the probability that the data will be lost and increasing the reliability of distance measurement and information communication.

Furthermore, when emitting the interrogation radio waves randomly, if the period is too long, the response will deteriorate, and conversely, if the period is too short, reflected signals from distant objects (outside the detection range) will be generated. may become a spurious signal, leading to erroneous distance measurements as if the object were present at a short distance. However, with this pulse communication method, the question Since the radio waves are emitted while being changed randomly within a predetermined period, the emitting period is divided into a period in which reflected waves from outside the detection range are not detected and a period in which the response is not deteriorated. An excellent effect is that the above-mentioned problems can be reliably eliminated by setting it within a range between 1 and 2.

[Brief explanation of the drawing]

The attached drawings show an embodiment of the ranging pulse communication system according to the present invention, in which FIG. 1 is a schematic block diagram, FIG. 2 is a detailed block diagram of the front transmitter, and FIG. 3 is a diagram of the rear receiver. Detailed block diagram, Figure 4 is a detailed block diagram of the information reading circuit, Figure 5 is a detailed block diagram of the rear transmitter, Figure 6 is a detailed block diagram of the front receiver, and Figure 7 is a detailed block diagram of the information reading circuit. 8 is a detailed block diagram of the distance detection circuit,
9 and 10 are waveform diagrams of various parts for explaining the operation of the system of the present invention. A: Question radio wave, B: Response radio wave, 1
・・・・・・Front transmitter forming the question transmitter, 2...
...first external code terminal to which an information signal is applied, 4...
...Rear receiver serving as a response receiver, 7...
・Information reading circuit, 9... Rear transmitter serving as a response transmitter, 10... Second external code terminal that applies a response dual purpose information signal, 11... Front receiver forming an interrogation receiver, 14...Information reading circuit, 1
6... Distance detection circuit.

Claims (1)

[Claims] 1 An interrogation radio wave consisting of a series of intermittent pulse radio waves pulse-modulated with a pulse train coded as an information signal from an interrogator is randomly varied within a predetermined period by a means that determines the emission pattern according to a predetermined value. In the transponder that receives this interrogation radio wave, the coded demodulated pulse train is demodulated from the received radio wave and the information signal is read. A response radio wave in response to the radio wave is emitted reflectively, this radio wave is received by the interrogator, and the elapsed time from the start of emission of the interrogation radio wave to the arrival time of reception of the response radio wave is measured, and the interrogator A distance measuring pulse communication method characterized in that the distance from the transponder to the transponder is measured.