JP2006246029A - Communication system and communication equipment at traveling object side - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly continue communication processing when an antenna set in a traveling object passes on a twisting point and its peripheral area. <P>SOLUTION: A deciding means 9 decides whether or not either an antenna 2a or 2b at a vehicle C side passes on a twisting point 12a of an antenna 23 at a road side and its peripheral region L based on the reception signal of the antenna 2a installed at a vehicle C side, and communication equipment 1 communicates through the antenna 2b other than the antenna 2a at the vehicle C side whose passage has been decided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication system provided on the side of a mobile body such as an automobile or a railway, and a communication system between communication apparatuses provided on the road or on the roadside such as a road shoulder, and mobile side communication used in this communication system. Relates to the device.

As this type of communication system and mobile unit side communication device, a mobile information transmission device is disclosed (for example, see Patent Document 1). According to the configuration disclosed in Patent Document 1, the loop antenna of the communication device installed on the ground side is provided along the traveling direction of the moving body, and the twisting point (current intersection) is the loop antenna. Is provided. On the moving body side, the two frame antennas are provided so as to form a single coil surface at a distance from each other, and the two frame antennas are provided so as to face the loop antenna. Then, the on-vehicle transmission / reception device receives signals synthesized by giving a predetermined phase difference (for example, a phase difference of 90 degrees) to the signals given from the ground side communication device to the two frame antennas. I have to.
No. 7-41220

  In the communication system disclosed in this Patent Document 1, when a frame-shaped antenna provided on a moving body passes over a twisting point (on an intersection in the current direction) and its peripheral region, The amplitude goes from the maximum value to 0 and changes sharply to the maximum value. For this reason, even if it is assumed that the amplitude of the received signal from one antenna changes from 0 to the maximum value and the amplitude of the received signal of the other frame antenna is constant at the maximum, the phase of the combined signal changes greatly. End up.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication system capable of smoothly continuing communication processing even when an antenna installed on a moving body passes over a twisting point and its peripheral region, And it is providing the mobile body side communication apparatus utilized for this communication system.

  According to the first aspect of the present invention, the mobile communication device has a plurality of mobile antennas formed in a loop shape, and is configured to be able to communicate through the plurality of mobile antennas. A plurality of loop-side antennas having at least one twist point, and configured to communicate with the mobile-side communication device through the road-side antenna and the mobile-side antenna; The means is based on at least one signal level of a plurality of signal levels received through a plurality of mobile-side antennas so that the mobile-side antenna is on a twisted point of the road-side antenna or in a peripheral area thereof (hereinafter referred to as a predetermined area). The switching means is determined by the determining means that the mobile antenna is passing through the predetermined area. In some cases, since the energization of the mobile-side antenna is switched so that the mobile-side communication device communicates through an antenna other than the mobile-side antenna that is determined to pass, the antenna installed on the mobile body is above the twisting point. In addition, communication processing can be continued smoothly even when passing through the surrounding area.

  According to the second aspect of the present invention, when any one of the plurality of mobile-side antennas passes over the twisted point of the road-side antenna or its peripheral region, the loop-forming surface of the antenna other than the antenna is used. Since the loop forming surface of the roadside antenna is arranged so as to face the loop forming surface of the roadside antenna, the loop forming surface of the roadside antenna always faces the loop forming surface of the mobile antenna, so that communication processing can be continued reliably. become.

  According to invention of Claim 3, the roadside communication apparatus is comprised so that it may communicate by the magnetic field of the reference | standard phase and its opposite phase which arise in each of two adjacent loops via the twist point of a roadside antenna, When the mobile communication device communicates with a reference phase magnetic field, the signal generated at the mobile antenna is communicated as a reference phase. When the mobile communication device communicates with a magnetic field with an opposite phase to the reference phase, the signal generated at the mobile antenna is reversed. Since the compensation means compensates so as to communicate with each other, the communication process can be continued continuously without changing the phase during communication. That is, it is more preferable when communication processing is performed using a frequency modulation signal or phase modulation signal.

As in the fourth aspect of the invention, it is desirable to provide the discriminating means and the switching means on the moving body side. Further, as in the invention described in claim 5, it is desirable to provide an odd number of twist points of the roadside antenna along the road surface.
According to the invention of claim 6, the discriminating means compares the signal level received by at least one of the plurality of signal levels of the plurality of mobile antennas with a predetermined threshold level, and Since it is configured by a smoothing circuit that smoothes the output signal of the comparator, the circuit can be easily configured and the cost can be reduced.

According to the seventh aspect of the present invention, when a plurality of roadside antennas of the roadside communication device are arranged apart from each other in the traveling direction of the moving body, the discrimination threshold of the discrimination means, the roadside antenna, and the mobile body side antenna The distance between the ends of the multiple roadside antennas is set based on the size of the antenna and the distance between the multiple mobile antennas, so if multiple roadside antennas are installed adjacent to each other Even so, the communication process can be continued continuously.
According to the eighth aspect of the present invention, the roadside antenna of the roadside communication device is provided in a section where the mobile body stops in the travel path of the mobile body. You can go down.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a road-vehicle communication system suitable for IMTS (Intelligent Multimode Transit System) and a vehicle-side communication device used in the communication system will be described with reference to FIGS. 1 to 3. explain.
IMTS is a new transportation system that has been attracting attention in recent years, and is a system that enables both unmanned and manned driving. On private roads, unmanned automatic driving and platooning are possible along magnetic markers buried in the center of the road surface. In addition, on ordinary roads, it is possible to carry out independent traveling manually as with ordinary buses. For this reason, as a system that combines the punctuality, high speed, and transportation capacity of railway-type transportation systems such as railways with the economics and flexibility of route buses, passengers are attracting attention because they do not need to change trains. System. While this is a highly convenient system, there is a risk that traffic accidents will increase if you make a mistake. Therefore, an embodiment in which traffic accidents can be suppressed as much as possible will be described.

FIG. 1 schematically shows the configuration of a road-vehicle communication system. In order to facilitate understanding of the description of the present invention, the scale of the drawings is different from the actual scale.
The road-to-vehicle communication system A includes a vehicle (for example, bus) C-side communication device (corresponding to a mobile communication device) 1 as a mobile body, and a road-side communication device (corresponding to a road communication device) 21. And operates as a closed communication system. The communication device 1 includes two (a plurality of) frame-shaped antennas 2a and 2b (corresponding to a mobile object side antenna) formed in a loop shape, hybrid circuits 3a and 3b, power circuits 4a and 4b, a discrimination control circuit 5, a reception A circuit 6 and a transmission circuit 7 are provided.
On the other hand, the communication device 21 is fixedly installed on the road surface R. The communication device 21 includes a roadside transmission / reception device 22 and an antenna 23. The antenna 23 is provided with three (odd number) twist points 23a at equal intervals, and four (even numbers) loops 24a to 24d are formed by these three twist points 23a. .

  The distance between the adjacent twist points 23a and 23a is set to about 50 m, for example, and the overall length of the antenna 23 is about 200 m along the traveling direction of the vehicle C. The reason for providing the twisted point 23a is to perform communication using weak radio waves in accordance with the Radio Law, and to suppress the electromagnetic field strength of radiated radio waves in the distance as much as possible. Furthermore, the reason why the antenna 23 is formed in an even number of loops is that a voltage is induced to the antenna 23 by electromagnetic noise coming from outside, but this adverse effect is canceled.

  When the vehicle C normally travels on the road surface R, the antennas 2a and 2b are arranged so that the antenna 23 and the loop formation surface face each other. These mobile-side communication devices 1 and road-side communication devices 21 are configured to be capable of wireless communication through antennas 2 a and 2 b and an antenna 23. In the road-vehicle communication system A, the transmission / reception frequency is set to be different between the communication device 1 on the vehicle C side and the communication device 21 on the road side. Specifically, the carrier frequency for transmission of the communication device 1 on the vehicle side is set to about 460 kHz, and the carrier frequency for transmission of the communication device 21 on the road side is set to about 190 kHz, so that adverse effects due to interference can be suppressed as much as possible. Is set.

<About the configuration of the communication device 1 on the mobile body>
The circuit on the receiving side is configured as follows. Even if the vehicle C travels, the antennas 2a and 2b are installed so that the distance from the antenna 23 installed on the road surface R on which the vehicle C travels is substantially the same distance. These antennas 2a and 2b are constituted by, for example, loop antennas, and are arranged such that the loop formation surfaces of the antennas 2a and 2b are parallel to the formation surfaces of the loops 24a to 24d of the roadside antenna 23. .

  The antennas 2a and 2b are installed along the road surface R at a certain distance from the traveling direction of the vehicle C. For example, one antenna (for example, the antenna 2a) is placed on the twisting point 23a or its When passing through the peripheral region L (predetermined region), the other antenna (for example, the antenna 2b) is disposed such that the loop formation surface of the other antenna (for example, the antenna 2b) faces the formation surfaces of the loops 24a to 24d of the roadside antenna 23. These antennas 2a and 2b are electrically connected to the hybrid circuits 3a and 3b, respectively.

The hybrid circuit 3a is configured by, for example, a so-called communication transformer. The hybrid circuit 3 a is connected to the antenna 2 a and is connected to the discrimination control circuit 5. When receiving a signal from the antenna 23 of the communication device 21 through the antenna 2 a, the hybrid circuit 3 a is supplied to the discrimination control circuit 5. It has become.
Similarly to the hybrid circuit 3a, the hybrid circuit 3b is composed of, for example, a communication transformer, and is connected to the antenna 2b and to the discrimination control circuit 5. When the hybrid circuit 3b receives a signal from the antenna 23 of the communication device 21 through the antenna 2b, the hybrid circuit 3b gives the received signal to the discrimination control circuit 5.

  When receiving a signal from the hybrid circuits 3a and 3b, the discrimination control circuit 5 filters and amplifies the received signal as necessary based on the received signal from the hybrid circuit 3a among the received signals, and shapes the waveform into a pulse signal. Thereafter, energization switching is performed to any one of the reception signals from the hybrid circuits 3a and 3b, and the signal is supplied to the reception circuit 6. The receiving circuit 6 digitally demodulates the given signal.

  The transmission side is configured as follows. The transmission circuit 7 generates a digital modulation signal by MSK (Minimum Shift Keying) and supplies it to the discrimination control circuit 5. When a signal is given from the transmission circuit 7, the discrimination control circuit 5 shapes the modulation signal as necessary, switches energization based on the reception signal given from the antenna 2a through the hybrid circuit 3a, and sends the modulation signal to the power circuit. 4a or 4b is provided. A specific configuration example of the discrimination control circuit 5 will be described later.

Power circuits 4a and 4b have the same circuit configuration. When the power circuit 4a receives the modulation signal from the discrimination control circuit 5, the power circuit 4a amplifies the power of the modulation signal, cuts the harmonics by a filter, and supplies the resultant to the hybrid circuit 3a. Similarly, when the power circuit 4a receives the modulation signal from the discrimination control circuit 5, the power circuit 4a amplifies the power of the modulation signal, limits the band with a filter, and supplies the band to the hybrid circuit 3b. In addition, the structure currently disclosed by Unexamined-Japanese-Patent No. 2003-51724 is applicable to these power circuits 4a and 4b, for example.
When a signal is given from the power circuit 4a, the hybrid circuit 3a radiates radio waves to the outside through the antenna 2a. When a signal is given from the power circuit 4b, the hybrid circuit 3b radiates radio waves to the outside through the antenna 2b.

The electrical configuration of the discrimination control circuit 5 will be specifically described below with reference to FIG.
The discrimination control circuit 5 receives a signal from the antennas 2a and 2b through the hybrid circuits 3a and 3b and performs waveform shaping processing, and is provided from the antennas 2a and 2b through the hybrid circuits 3a and 3b and the waveform shaping unit 8. A determining unit 9 that compares a received signal (for example, an amplitude level) with a predetermined threshold level Vth and a switching unit 10 that switches energization between the transmission signal and the received signal according to the determination result of the determining unit 9 are provided. .

The waveform shaping unit 8 includes bandpass filters 11a and 11b, amplifiers 12a and 12b that receive signals from the bandpass filters 11a and 11b, respectively, and waveform shaping circuits 13a and 13b that receive signals from the amplifiers 12a and 12b, respectively. ing.
Each of the bandpass filters 11a and 11b is configured by a filter that passes a predetermined band, and is configured to pass a reception signal of a predetermined band when a reception signal is given from each of the hybrid circuits 3a and 3b. Yes.

When receiving signals from the bandpass filters 11a and 11b, the amplifiers 12a and 12b amplify the received signals. Each of the waveform shaping circuits 13a and 13b is constituted by, for example, a limiter, and shapes the received signal into a pulse signal and gives it to the switching means 10.
The discriminating means 9 includes a comparator 14 and a smoothing circuit 15. The comparator 14 is constituted by a comparator, for example, and compares a predetermined threshold voltage level Vth with the output signal voltage of the amplifier 12a. When the voltage is higher than the threshold voltage level Vth, the output voltage of the amplifier 12a is supplied to the smoothing circuit 15. However, when the voltage is lower than the threshold voltage level Vth, a 0 V DC voltage is applied to the smoothing circuit 15.

Further, the smoothing circuit 15 smoothes the applied voltage when the voltage is applied from the comparator 14 to make the voltage level constant. At this time, the output voltage of the smoothing circuit 15 is set in advance so as to correspond to the digital input of the switching means 10 installed in the subsequent stage. Specifically, when the amplitude of the output voltage of the amplifier 12a is greater than or equal to a predetermined value Vth, a “high” signal is supplied to the switching means 10, and the amplitude of the output signal of the amplifier 12a is less than the predetermined value Vth. In this case, a “low” signal is supplied to the switching means 10.
The switching means 10 includes NOT gates N1 to N5, AND gates A1 to A8, OR gates O1 to O5, and a flip-flop circuit FF1 as compensation means. The flip-flop circuit FF1 is configured to detect the rise of the output signal of the discriminating means 9 and invert the Q output in response to this rise. That is, the Q output is inverted when the amplitude of the output signal of the amplifier 12a changes from a state below a predetermined value to a high state.

<Electrical connection of the switching means 10a on the receiving side>
The receiving side switching means 10a constituting the switching means 10 is constituted by NOT gates N2 and N3, AND gates A1 to A4, OR gates O1 and O2, and O5 as compensation means.
The Q output of the flip-flop circuit FF1 is given to the inputs of the AND gates A1 and A3, and the / Q output of the flip-flop circuit FF1 is given to the inputs of the AND gates A2 and A4.

The output of the waveform shaping circuit 13a is given to the input of the AND gate A1, and the output of the waveform shaping circuit 13b is given to the input of the AND gate A3. The output of the waveform shaping circuit 13a is given to the input of the AND gate A2 via the NOT gate N2, and the output of the waveform shaping circuit 13b is given to the input of the AND gate A4 via the NOT gate N3. ing.
The output X of the discrimination means 9 is given to the inputs of the AND gates A1 and A2, and the output X of the discrimination means 9 is given to the inputs of the AND gates A3 and A4 as the inverted output / X via the NOT gate N1. It has been. The OR gates O1, O2, and O5 output the sum of these AND gates A1 to A4 to the receiving circuit 6.

<Electrical connection of transmission side switching means 10b>
The transmission side switching means 10b constituting the switching means 10 includes NOT gates N4 and N5, AND gates A5 to A8, and OR gates O3 and O4 as compensation means. The Q output of the flip-flop circuit FF1 is given to the inputs of the AND gates A5 and A7, and the / Q output of the flip-flop circuit FF1 is given to the inputs of the AND gates A6 and A8.

  The outputs of the transmission circuit 7 are given to the inputs of the AND gates A5 and A7, and the outputs of the transmission circuit 7 are given to the inputs of the AND gates A6 and A8 via the NOT gates N4 and N5, respectively. The output X of the discriminating means 9 is given to the inputs of the AND gates A5 and A6, and the output X of the discriminating means 9 is given as the inverted output / X through the NOT gate N1 to the inputs of the AND gates A7 and A8. It has been. The OR gates O3 and O4 give the sum of the outputs of these AND gates A5 to A8 to the power circuits 4a and 4b, respectively.

<About the structure of the communication apparatus 21 installed on the road surface R>
As illustrated in FIG. 1A, the roadside communication device 21 includes a roadside transmission / reception device 22 and an antenna 23. The roadside transmission / reception device 22 is configured to be able to transmit and receive an MSK-modulated digital modulation signal through the antenna 23.

The operation of the above configuration will be described below with reference to FIGS. 1B and 3 as well.
FIG. 1B schematically shows a relative positional relationship between the antenna on the vehicle C side and the antenna installed on the road surface R side. FIG. 3 schematically shows a signal state change of each node based on a relative position between the antennas by a timing chart. FIG. 3 shows the relative phase of the magnetic field generated in the roadside antenna 23. When the magnetic field H is a reference phase magnetic field, the magnetic field / H indicates a magnetic field having an opposite phase to the reference phase. . Further, the reference phase of the transmission signal when the transmission circuit 6 transmits is denoted by T, and the opposite phase is denoted by / T. Further, the reference phase of the received signal when the receiving circuit 6 receives is denoted by R, and the received signal when received at the opposite phase is denoted by / R.

  When the vehicle C travels on the road surface R, the relative positional relationship between the antennas 2a and 2b and the antenna 23 continuously changes as shown in FIG. At this time, the signal state of each node changes as shown in FIG. Hereinafter, the operation on the receiving side and the operation on the transmitting side will be described in particular with reference to FIG. 3A shows a timing chart when switching based on the received signal of the antenna 2a. In FIG. 3A, RX is a signal received by the receiving circuit 6, TXa represents a signal transmitted from the discrimination control circuit 5 to the power circuit 4a, and TXb represents a signal transmitted from the discrimination control circuit 5 to the power circuit 4b.

<Reception-side operation of roadside communication device 21>
When the relative positional relationship is in the state (1) of FIG. 1B, the loop formation surface of the antennas 2a and 2b faces the loop formation surface of the loop 24a. The amplitude becomes larger than a predetermined threshold voltage level Vth, and the output state X of the discrimination means 9 becomes the “high” state (see S0 in FIG. 3). At this time, assuming that the Q output of the flip-flop circuit FF1 is in the “high” state, the output state X of the discrimination means 9 and the Q output of the flip-flop circuit FF1 are given to the input of the AND gate A1 in the “high” state. Therefore, a signal received by the antenna 2a is supplied to the receiving circuit 6 through the waveform shaping unit 8, the AND gate A1, and the OR gates O1 and O5 (see R (2a) in FIG. 3). At this time, since the “low” signal is given to the inputs of the other AND gates A2 to A4 constituting the receiving side switching means 10a, the influence of the received signal by the antenna 2b is not given to the receiving circuit 6.

  Thereafter, in the process in which the relative positional relationship transitions from the state (1) in FIG. 1B to the state (2) in which the antenna 2a straddles the twisting point 23a, particularly in the loop formation plane of the antenna 2a. Since the number of magnetic fluxes interlinked with each other gradually decreases, and then the direction of a part of the magnetic field passing through the loop forming surface of the antenna 2a has an opposite phase, on the vehicle C side, with respect to the antenna 2a The amplitude of the induced voltage continuously decreases, and accordingly, the amplitude of the output voltage of the amplifier 12a also decreases continuously.

  The comparator 14 compares the signal level of the output voltage with a predetermined threshold voltage level Vth, and the smoothing circuit 15 smoothes the comparison output and supplies it to the switching means 10, so that the amplitude of the amplifier 12a is greater than the threshold voltage level Vth. When it becomes low, the output state X (the input state of the switching unit 10) of the determination unit 9 changes from the “high” state to the “low” state (S1 in FIG. 3).

  At this time, since the Q output of the flip-flop circuit FF1 is in the “high” state and the / Q output is in the “low” state, the Q output of the flip-flop circuit and the output of the discrimination means 9 are input to the AND gate A3. The inverted signal of the output is supplied in the “high” state, and the reception signal of the antenna 2b is supplied to the reception circuit 6 through the waveform shaping unit 8, the AND gate A3, and the OR gates O2 and O5. At this time, since the “low” signal is given to the inputs of the other AND gates A1, A2 and A4 constituting the receiving side switching means 10a, the reception circuit 6 may be influenced by the reception signal of the antenna 2a. Absent.

  Thereafter, the vehicle C further moves, and the relative positional relationship between the antennas 2a and 2b and the antenna 23 changes from the state (2) in FIG. 1 (b) to the state (3) in which the antenna 2b straddles the twisting point 23a. In the process of transition, the number of magnetic fluxes interlinking with the loop formation region of the antenna 2b gradually decreases, and then a part of the magnetic field passing through the loop of the antenna 2b has an opposite phase. In FIG. 2, the amplitude of the induced voltage of the antenna 2b continuously decreases, and accordingly, the amplitude of the output voltage of the amplifier 12b also decreases continuously.

  However, at the same time, since the loop forming surface of the antenna 2a passes through the twisting point 23a and faces the antenna 24b, the amplitude of the amplifier 12a gradually increases, and this amplitude exceeds the threshold voltage level Vth. It becomes like this. Then, the output state X (the input state of the switching unit 10) X of the determination unit 9 changes from the “low” state to the “high” state (see S2 in FIG. 3). The flip-flop circuit FF1 receives the rising edge of the state X and inverts the Q output and the / Q output.

  At this time, since the / Q output of the flip-flop circuit FF1 and the output state X of the discriminating means 9 are given to the input of the AND gate A2 in the “high” state, the received signal of the antenna 2a is supplied to the waveform shaping unit 8 and the NOT. The signal is applied to the receiving circuit 6 through the gate N2, AND gate A2, and OR gates O1 and O5. At the same time, since the “low” signal is given to the inputs of the other AND gates A1, A3 and A4 constituting the receiving side switching means 10a, the influence of the received signal of the antenna 2b is not given to the receiving circuit 6.

  Since the NOT gate N2 inverts the output signal of the waveform shaping unit 8, even if the magnetic fields generated in the adjacent loops 24a and 24b are in opposite phases, the voltage induced in the antenna 2a has an adverse effect. It is possible to compensate, and a signal can be given to the receiving circuit 6 in a state where the influence is compensated. Therefore, in the state (3) in FIG. 3, a signal having the same phase as that in the state (1) is supplied to the receiving circuit 6 (see S3 and R (2a) in FIG. 3). In the state (2), a signal having the same phase as that in the state (1) is given to the receiving circuit 6. Therefore, in the states (1) to (3), signals having the same phase are all given to the receiving circuit 6. .

  Returning to FIG. 1B, after this, the vehicle C further moves, and the relative positional relationship between the antennas 2a and 2b and the antenna 23 changes from the state (3) in FIG. 1B to the loop formation of the antenna 2a. In the process of transitioning to the (4) state where the surface straddles the twisting point 23a, the amplitude of the induced voltage of the antenna 2a continuously decreases as described above, and the amplitude of the output voltage of the amplifier 12a also continues accordingly. To drop.

  At this time, since the / Q output of the flip-flop circuit FF1 and the inverted output / X of the signal of the discrimination means 9 are given to the input of the AND gate A4 in the “high” state, the received signal of the antenna 2b is converted into the waveform shaping unit 8 And the NOT gate N3, the AND gate A4, and the OR gates O2 and O5. At this time, since the “low” signal is given to the inputs of the other AND gates A1 to A3 constituting the receiving side switching means 10a, the influence of the received signal of the antenna 2a is not given to the receiving circuit 6.

  Since the NOT gate N3 inverts the output of the waveform shaping unit 8, it is possible to give a signal to the receiving circuit 6 in a state in which compensation for the influence caused by the opposite phase of the magnetic field between the adjacent loops 24a and 24b is maintained. it can. Therefore, in the state (4), a signal having the same phase as that in the states (1) to (3) is supplied to the receiving circuit 6 (see R (2b) in FIG. 3).

  Thereafter, the vehicle C further moves, and the relative positional relationship between the antennas 2a and 2b and the antenna 23 is such that the loop forming surface of the antenna 2b straddles the twisting point 23a from the state (4) in FIG. Accordingly, on the vehicle C side, the amplitude of the induced voltage of the antenna 2b continuously decreases, and accordingly, the amplitude of the output voltage of the amplifier 12b also decreases continuously.

  However, at the same time, since the loop forming surface of the antenna 2a passes over the twisting point 23a and faces the loop forming surface of the antenna 24b, the amplitude of the amplifier 12a gradually increases, and this amplitude becomes the threshold value. It exceeds the voltage level Vth. Then, the input state X of the switching means 10 changes from the “low” state to the “high” state (see S5 in FIG. 3). In response to the change in the input state X, the flip-flop circuit FF1 inverts the Q output and the / Q output.

  At this time, since the Q output of the flip-flop circuit FF1 and the output of the discriminating means 9 (input state X of the switching means 10) are given to the input of the AND gate A1, the received signal of the antenna 2a is The signal is given to the receiving circuit 6 through the waveform shaping unit 8 and NOT gate N2, AND gate A1 and OR gates O1 and O5. At this time, since the “low” signal is given to the inputs of the other AND gates A2 to A4 constituting the switching means 10a, the influence of the reception signal of the antenna 2b is not given to the reception circuit 6 (S6 and FIG. 3). R (2a)). This state matches the state (1) described above. That is, these (1) to (4) states are repeated.

<About the transmission operation of the communication device 1 on the vehicle C side>
Hereinafter, the transmission process of the communication apparatus 1 will be described. The transmission circuit 7 generates a digital modulation signal by MSK, radiates a radio wave from the antenna 2a or 2b through the discrimination control circuit 5, the power circuit 4a or 4b, and the hybrid circuit 3a or 3b, and transmits the radio wave to the roadside communication device 21. It has become.

  With reference to FIG. 3, the operation at this time will be mainly described with reference to the switching operation of the transmission-side switching means 10b in FIG. When the vehicle C travels on the road surface R, the relative positional relationship between the antennas 2a and 2b and the antenna 23 continuously changes as shown in FIG. At this time, the input state X of the switching means 10, its inverted state / X, the Q output of the flip-flop FF1, and its inverted output / Q change as shown in FIG.

  At this time, when the positional relationship between the antennas 2a and 2b is in the state (1) in FIG. 1B, the output state X of the discriminating means 9 and the Q output of the flip-flop circuit FF1 are “input” to the AND gate A5. Since the signal is given in the “high” state, the output signal of the transmission circuit 7 is given to the power circuit 4a through the AND gate A5 and the OR gate O3. That is, the output signal of the transmission circuit 7 is transmitted through the antenna 2a. At this time, since the “low” signal is given to the inputs of the other AND gates A6 to A8 constituting the transmission side switching unit 10b, the output signal of the transmission circuit 7 is not transmitted through the antenna 2b.

  Thereafter, in the process in which the relative positional relationship changes from the (1) state of FIG. 1B to the (2) state where the antenna 2a straddles the twisting point 23a, the output state of the discriminating means 9 (the switching means 10) The input state X changes from the “high” state to the “low” state (see S1 in FIG. 3).

  At this time, since the Q output of the flip-flop circuit FF1 is in the “high” state and the / Q output is in the “low” state, the Q output of the flip-flop circuit and the output of the discrimination means 9 are input to the AND gate A7. An inverted output signal is provided in the “high” state. At this time, the output signal of the transmission circuit 7 is supplied to the power circuit 4b through the AND gate A7 and the OR gate O4, and is transmitted from the antenna 2b (see S2 and T (2b) in FIG. 3). At this time, similarly to the above, since a “low” signal is given to the inputs of the other AND gates A5, A6 and A8 constituting the transmission side switching means 10b, no transmission signal is given to the power circuit 4a and the antenna. 2a is not transmitted.

  Thereafter, the vehicle C further moves, and the relative positional relationship between the antennas 2a and 2b and the antenna 23 changes from the state (2) in FIG. 1 (b) to the state (3) in which the antenna 2b straddles the twisting point 23a. In the process of transition, the input state X of the switching means 10 transitions from the “low” state to the “high” state (see S2 in FIG. 3). In response to the change in the input state X, the flip-flop circuit FF1 inverts the Q output and the / Q output.

  At this time, since the / Q output of the flip-flop circuit FF1 and the output of the discriminating means 9 are given to the input of the AND gate A6 in the “high” state, the transmission signal of the transmission circuit 6 is the NOT gate N4 and the AND gate A6. And supplied to the power circuit 4a through the OR gate O3. At the same time, since the “low” signal is given to the inputs of the other AND gates A5, A7 and A8 constituting the transmission side switching means 10b, the transmission signal of the transmission circuit 6 is not given to the antenna 2b.

  At this time, since the NOT gate N4 inverts the transmission signal of the transmission circuit 7, in the state (3) in FIG. 3, a signal having a phase opposite to that in the state (1) is transmitted through the antenna 2a on the vehicle C side. (See / T (2a) in (3) of FIG. 3). When the roadside communication device 21 receives this transmission signal in the loop 24b of the roadside antenna 23, the roadside communication device 21 receives it in the opposite phase to the case of (1). For this reason, as a result, the roadside transmission / reception device 22 receives in the same phase as the state (1).

  That is, in other words, since the transmission signal of the transmission circuit 7 is inverted in advance so as to compensate for the effect of phase inversion at the time of reception, in the (3) state, communication can be performed using a signal having the same phase as the (1) state. . Since the communication device 1 on the vehicle C side transmits a signal having the same phase as that in the state (1) in the state (2), the roadside transmission / reception device 22 is all in the same phase in the states (1) to (3). The signal can be received.

Returning to FIG. 1B, after this, the vehicle C further moves, and the relative positional relationship between the antennas 2a and 2b and the antenna 23 changes from the state (3) in FIG. In the process of transitioning to the (4) state across 23a, the / Q output of the flip-flop circuit FF1 and the inverted output / X of the signal of the discriminating means 9 are in the "high" state at the input of the AND gate A8, as described above. Therefore, the transmission signal of the transmission circuit 7 is supplied to the power circuit 4b through the NOT gate N5, the AND gate A8, and the OR gate O4, and the signal is transmitted through the antenna 2b. At this time, since the NOT gate N5 inverts the transmission signal of the transmission circuit 7, it is possible to transmit the signal while maintaining the compensation of the influence caused by the opposite phase of the magnetic field between the adjacent loops 24a and 24b ( (See / T (2b) in FIG. 3).
At this time, since the “low” signal is given to the inputs of the other AND gates A5 to A7 constituting the transmission side switching means 10b, no signal is transmitted from the antenna 2a. These (1) state to (4) state are repeated.

(Modification)
The operation shown in FIG. 3A described above is that the switching means 10 switches the energization state based on the received signal from the antenna 2a, so that the output of the amplifier 12a is connected to the input of the comparator 14. Although the operation based on the above-described configuration is shown, the present invention is not limited to this, and the switching means 10 may switch energization based on the received signal from the antenna 2b. Instead of the configuration in which the output of the amplifier 12 a is connected to the input of the comparator 14, the output of the amplifier 12 b is connected to the input of the comparator 14. In this case, it is also necessary to change the circuit of the switching means 10, but since this circuit change is easy, the description thereof is omitted. FIG. 3B shows the timing when the loop forming surface of the antenna 2 b passes through the corresponding position of the roadside antenna 23. Although detailed description of the operation is omitted, the signal state changes as shown in FIG. 3B, and in this case as well, communication processing can be continued smoothly as described above.

  According to the present embodiment, the determination unit 9 is connected to the vehicle C side based on one of the two reception signals received by the communication device 1 through the antennas 2a and 2b installed on the vehicle C side. It is determined whether any of the antennas 2a and 2b is passing over the twisting point 23a of the roadside antenna 23 or in the surrounding area L, and the vehicle C side antenna 2a or 2b determined to be passing is determined. Since the communication device 1 communicates through an antenna other than the antenna 1, the change in the amplitude of the signal that occurs when the antennas 2a and 2b installed on the vehicle C side sequentially pass over the twisting point 23a or its peripheral region L. And communication can be performed while avoiding phase changes, and communication processing can be continued smoothly.

  For example, in the system disclosed in Patent Document 1, a digital modulation communication system such as a frequency modulation system (FSK modulation system or MSK modulation system whose modulation index is 0.5) or a phase modulation system (PSK modulation system) is used. If it is adopted, problems will occur. That is, in Patent Document 1, when the on-vehicle transmission / reception apparatus receives a signal, the moving body passes over the twisting point (intersection of the current direction) by synthesizing the signals given to the two frame antennas. Accordingly, signals having four different phases are received (see FIGS. 3A to 3E of Patent Document 1). For this reason, when the digital modulation communication method is applied, it is necessary to detect the twist point by some means on the mobile body side and reflect it in the phase difference of the synthesized signal, but it has been practically difficult until now. That is, the communication system disclosed in Patent Document 1 is unsuitable when a frequency modulation scheme or a phase modulation scheme is employed.

  According to this embodiment, when the roadside communication device 21 communicates with the reference phase generated in the two adjacent loops 24a and 24b via the twisted point 23a of the roadside antenna 23 and the magnetic field of the opposite phase, respectively. The communication device 1 on the vehicle C side communicates with signals generated in the antennas 2a and 2b on the vehicle C side as a reference phase when communicating with a reference phase magnetic field, and communicates with a magnetic field with an opposite phase to the reference phase. Since the signals generated in the antennas 2a and 2b on the vehicle C side are communicated with opposite phases, the influence of the opposite phase of the magnetic field due to the presence of the twisted point 23a in the antenna 23 can be compensated. Even if a frequency modulation method or a phase modulation method is applied, smooth communication can be continued.

  For example, in Patent Document 1, if the moving speed is higher than a predetermined speed when the moving body passes over the twisting point, a communication error on the twisting point can be eliminated by some method. When the moving speed of the body is slow, it takes a long time to pass through the twisting point and its peripheral region L, and there is a concern that communication becomes impossible at the twisting point and a problem occurs. In this regard, in this embodiment, communication is not disabled even if the moving speed of the vehicle C is slow.

  Moreover, it is preferable to provide the discrimination means 9 and the switching means 10 on the vehicle C side. In addition, since the odd-numbered twist points 23a of the roadside antenna 23 are provided along the road surface R, an even number of loops 24a to 24d can be formed. Great noise reduction effect.

  The discriminating means 9 compares the amplitude of the signal received by one of the digitally modulated signals received by the antennas 2a and 2b with a predetermined threshold voltage level Vth, and the comparator 14 Therefore, the circuit configuration can be simplified and the cost can be reduced.

  If such a road-to-vehicle communication system A is applied, even if the speed of the vehicle C is high, smooth communication can be continuously performed even if the vehicle C is traveling in a place where traffic congestion is likely to occur. A traffic accident can be suppressed as much as possible by turning on / flashing a warning light, a signal light, or the like for suppressing the speed, for example, according to the communication signal of the road-vehicle communication system A.

(Second Embodiment)
4 and 5 illustrate the second embodiment of the present invention. The difference from the previous embodiment is that a plurality of roadside communication devices 21 are arranged over a long distance along the traveling direction of the vehicle C. FIG. It is where it was installed. About the same structure as the above-mentioned embodiment, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted. FIG. 4 shows a schematic diagram. In FIG. 4, the road-side communication device 21 is provided with one twisting point 23a, and the road-side communication device 21 in FIG. Although it is written so that the form is different, it is shown in this way because there is no substantial difference if an odd number of twist points 23a are provided.

In order to make the road-to-vehicle communication system A of the above-described embodiment practical, it is necessary to provide a so-called blocking device so that a plurality of roadside communication devices 21 are installed on the road surface R. In particular, a plurality of antennas 23 are provided on the road surface R. It is necessary to install along.
In this case, since a plurality of roadside antennas 23 are often installed independently, as shown in FIGS. 4B and 5, the phases of the magnetic fields of the adjacent loops 24b and 24a are worst. In this case, the phase may be relatively the same (see the magnetic field / H of the loop 24b and the magnetic field / H of the loop 24a in FIG. 5).

  In this case, the amplitude of the voltage induced in the antennas 2a and 2b on the vehicle C side becomes larger than when one twist point 23a exists in the region of the distance d, and the determination means 9 uses these antennas 2a. Alternatively, even if it is determined whether or not it is on the twisting point 23a or its peripheral region L based on the induced voltage 2b, the amplitude of the output of the amplifier 12a or 12b becomes larger than the threshold voltage level Vth for determination. There is a risk of it. For this reason, when the antennas 2a and 2b on the vehicle C side pass between the antennas 23 of the plurality of roadside communication devices 21, there is a possibility that communication cannot be continued.

  Therefore, when a plurality of antennas 23 of the roadside communication device 21 are arranged apart from each other in the traveling direction of the vehicle C, the threshold voltage level Vth of the discrimination means 9 of the discrimination control circuit 5 and the plurality of roadside The distance d between the end portions 23b of the plurality of roadside antennas 23 is set based on the size of the antenna 23, the sizes of the plurality of antennas 2a and 2b on the vehicle C side, and the distance between the plurality of antennas 2a and 2b. It is desirable to do. At this time, the distance d between the end portions 23b of the adjacent antennas 23 is required to be larger than the diameters of the antennas 2a and 2b on the vehicle C side.

  Then, as shown in FIG. 5, the input state X of the switching unit 10 can be set to the “low” state (see S <b> 7 in the state X of FIG. 5), and the switching unit 10 can reliably switch the state. In FIG. 5C, detailed description is omitted, but in the section Z1, the transmission TXa, TXb, and the reception RX can be performed in the same phase, and further, the section Z2 adjacent to the section Z1. In the communication processing, both transmission TXa and TXb and reception RX can be performed in the same phase.

  That is, between the section Z1 and the section Z2, the transmission TXa and TXb are in the same phase and the reception RX is in each section Z1 and Z2, even if the communication processing between the adjacent roadside transmission / reception devices 22 is not synchronized. Since the phase is set to be the same, communication using the digital modulation signal can be smoothly performed for each of the sections Z1 and Z2. In this way, communication processing can be continued continuously. Further, as shown in FIG. 5D, when the communication state corresponding to the position of the antenna 2b is continued, the detailed description is omitted, but it is substantially the same.

  According to such an embodiment, when a plurality of roadside antennas 23 are disposed apart from each other in the traveling direction of the vehicle C, the threshold voltage level Vth for discrimination of the discrimination means 9 and the The distance d between the end portions 23b of the roadside antenna 23 is set based on the sizes of the loops 24b and 24a and the antennas 2a and 2b on the vehicle C side and the distance between the antennas 2a and 2b on the vehicle C side. Even if the twisting point 23a does not exist in the region of the distance d between the end portions 23b, the communication can be continued continuously and smoothly.

(Third embodiment)
FIG. 6 shows an explanation of the third embodiment of the present invention. The difference from the above-described embodiment is that the section where the vehicle C stops on the path of the vehicle C along the road surface R. Is provided. The same parts as those of the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described below.
In order to make such a road-vehicle communication system A practical, it is necessary to construct a system over a longer distance than in the above embodiment. However, such a road-to-vehicle communication system A requires a large amount of money to build a roadside infrastructure. Therefore, as shown in FIG. 6, the roadside communication device 21 (roadside antenna 23) is installed in the section K1 where the vehicle C stops, and the communication device 21 is not installed in the section K2 where the vehicle C does not stop. Thereby, cost reduction can be aimed at.

(Other embodiments)
The present invention is not limited to the above embodiment, and for example, the following modifications or expansions are possible.
Although applied to a road-to-vehicle communication system suitable for IMTS, the present invention is not limited to this, and a mobile that performs communication between a communication device installed in a railway vehicle and a communication device installed on a road shoulder or the like It can also be applied to a communication system between roadside communication devices.

Although the embodiment in which the antenna 23 is installed on the road surface R is shown, it may be installed in the road.
Although the embodiment in which the discriminating means 9 and the switching means 10 are provided on the vehicle C side is shown, they may be provided outside the vehicle C. Further, the flip-flop circuit FF1 and NOT gates N2 to N5 constituting the compensation means may be provided outside the vehicle C.
In the above-described embodiment, an embodiment has been described in which communication is performed using a signal digitally modulated by MSK (Minimum Shift Keying). However, the present invention is not limited to this, and FSK (Frequency Shift Keying) modulation or PSK (Phase Shift Keying) modulation is used. Communication using a digital modulation method based on the above may be used.

Although the embodiment provided with two frame-shaped antennas 2a and 2b as two moving body side antennas has been described, the present invention is not limited to this and may be configured with three or more loop antennas.
1 and 4 show that the antennas 2a and 2b are installed outside the vehicle C. However, the present invention is not limited to this. For example, the antennas 2a and 2b are installed in the vehicle C. Anyway.

Explanatory drawing which shows the 1st Embodiment of this invention ((a) Schematic block diagram of the communication system between a mobile body side and a roadside, (b) The relative positional relationship of a mobile body side antenna and a roadside antenna typically Figure shown) The figure which shows an example of a structure of a discrimination | determination control circuit Timing chart showing signal status of each node FIG. 1 equivalent diagram showing a second embodiment of the present invention 3 equivalent figure Explanatory drawing of the communication system which shows the 3rd Embodiment of this invention.

Explanation of symbols

  In the drawings, 1 is a vehicle side communication device (mobile body side communication device), 2a and 2b are vehicle side antennas, 9 is a discrimination means, 10 is a switching means, 21 is a roadside communication device (roadside communication device), and 23 is A roadside antenna, 23a is a twist point, A is a road-to-vehicle communication system (communication system), C is a vehicle (moving body), and R is a road surface.

Claims (9)

A mobile-side communication device that has a plurality of mobile-side antennas formed in a loop and is configured to be communicable through the plurality of mobile-side antennas;
A roadside communication device having a plurality of loop-shaped roadside antennas having at least one twisting point and communicating with the mobile body side communication device through the roadside antenna and the mobile body side antenna;
Based on at least one signal level of a plurality of signal levels received through the plurality of mobile-side antennas, the mobile-side antenna is on a twisted point of the road-side antenna or in a peripheral region thereof (hereinafter referred to as a predetermined region). Determining means for determining whether or not it passes,
When the determination unit determines that the mobile-side antenna passes through the predetermined area, the mobile-side communication device communicates through an antenna other than the mobile-side antenna that is determined to pass. A communication system comprising switching means for switching energization of the mobile unit antenna.   When any one of the plurality of mobile-side antennas passes over a twisted point of the road-side antenna or a peripheral region thereof, the loop-forming surface of the road-side antenna is in a loop-forming surface of an antenna other than the antenna. The communication system according to claim 1, wherein the communication system is disposed so as to face each other. The roadside communication device is configured to communicate with a reference phase generated in each of two adjacent loops via a twisted point of the roadside antenna and a magnetic field of an opposite phase thereof,
The mobile communication device communicates with a signal generated in the mobile antenna as a reference phase when communicating with the magnetic field of the reference phase, and occurs in the mobile antenna when communicating with a magnetic field with an opposite phase to the reference phase. The communication system according to claim 1 or 2, further comprising compensation means for compensating for communication so that the signal is communicated in an opposite phase.   The communication system according to claim 1, wherein the mobile communication device includes the determination unit and the switching unit.   The communication system according to claim 1, wherein an odd number of twist points of the roadside antenna are provided along the road surface.   The discrimination means compares a signal level received by at least one of the plurality of signal levels of the plurality of mobile antennas with a predetermined threshold level, and smoothes the output signal of the comparator 6. The communication system according to claim 1, wherein the communication system is configured by a smoothing circuit.   When a plurality of roadside antennas of the roadside communication device are disposed apart from each other in the traveling direction of the moving body, a determination threshold value of the determination unit, a size of the roadside antenna and the mobile body side antenna, and a plurality of The communication system according to any one of claims 1 to 6, wherein a distance between end portions of the plurality of roadside antennas is set based on a distance between mobile body side antennas.   The communication system according to any one of claims 1 to 7, wherein the roadside antenna of the roadside communication device is provided in a section in which the moving body stops in the passage of the moving body. Plural formed in a loop with a roadside communication device having a plurality of mobile antennas formed in a loop and having a plurality of looped antennas having at least one twist point Configured to communicate through the mobile antenna
Based on at least one signal level of a plurality of signal levels received through a plurality of mobile-side antennas, the mobile-side antenna is within a twisted point of the road-side antenna and its surrounding area (hereinafter referred to as a predetermined area). Determining means for determining whether or not
When the determination unit determines that the mobile-side antenna passes through the predetermined area, the mobile-side communication device communicates through an antenna other than the mobile-side antenna that is determined to pass. A mobile-side communication device comprising switching means for switching the mobile-side antenna.

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