JP3501047B2 - In-vehicle device for non-stop automatic toll collection (ETC) system and vehicle trajectory management system using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle device for a non-stop automatic toll collection (ETC) system, and in particular, makes it possible to tune its carrier frequency in advance before starting wireless communication with a roadside wireless device. The present invention relates to an on-vehicle device for ETC system.

[0002]

2. Description of the Related Art Intelligent Transport System ITS (Inte
Illigent Transport Systems)
As a prelude to promotion, non-stop automatic fee collection (E
The TC) system is scheduled to start operating in 1999 (White Paper on Communications in 1999: edited by the Ministry of Posts and Telecommunications).

ETC (Electronic Toll)
At the toll gate of the toll road, the vehicle is installed in the vehicle while the vehicle passing through the toll gate does not stop and passes through the communication zone of 4 m in the toll gate lane at a maximum speed of 80 km / h. Dedicated short-distance communication (DSRC: Dedicated Short) between the on-board device for ETC and the roadside wireless device installed at the tollgate.
This is a system for automatically collecting tolls by performing wireless communication called “range communication”.

[0004]

DISCLOSURE OF THE INVENTION In DSRC wireless communication for ETC, when a vehicle tries to pass through a communication zone of a driving lane such as a tollgate, it is immediately connected with an ETC on-vehicle device mounted in the vehicle. In order to enable communication, the roadside wireless device forms a communication zone with a fixed carrier frequency for each driving lane.

In addition, the communication zone formed by the roadside wireless device is provided in order to prevent interference between adjacent driving lanes.
One of the two types of carrier frequencies is set so that adjacent communication zones have different carrier frequencies.

To cope with this, the ETC on-vehicle device is
As a pre-process for DSRC wireless communication, the carrier frequency of the roadside wireless device of the traveling lane for the ETC which is about to pass is recognized and the frequency is tuned to that frequency so as to be able to communicate with the roadside wireless device of either carrier frequency. Need a means of selection. In other words, the conventional general on-vehicle device for ETC sends out from the on-vehicle device to detect the electric field level detection circuit inside the on-vehicle device to detect whether or not the vehicle has entered the communication zone, and the carrier frequency of the communication zone. It requires a timer circuit to change the frequency of radio waves periodically.

However, this conventional general ETC
There are the following problems in the frequency selecting means of the vehicle-mounted device.

The first problem is that an electric field level detection circuit, a timer circuit, etc. are required inside the vehicle-mounted device in order to realize the frequency selection means, and the circuit scale and software scale of the vehicle-mounted device increase. is there. Since the scale of the vehicle-mounted device increases, there is a problem that the power-saving of the vehicle-mounted device cannot be achieved.

The second problem is that in the initial operation of the DSRC wireless communication, at least one frame of the communication frames of the DSRC wireless communication must be used in order to confirm the matching of the carrier frequency with the roadside apparatus. E
This means that the number of communication frames used for the original wireless communication processing for TC is reduced, and the wireless communication is time-limited.

An object of the present invention is to provide an on-vehicle device for an ETC system, which has a small circuit scale and a small software scale, and can use a communication frame of DSRC wireless communication for the maximum ETC processing. is there.

[0011]

An on-vehicle device for an ETC system of the present invention is mounted on a vehicle and is used for dedicated short-range communication (DSRC: Dedicated Sho) with a roadside wireless device.
Non-stop automatic toll collection (ETC: Electro) that performs rt Range Communication
nic toll collection) vehicle-mounted device, wherein the ETC system vehicle-mounted device includes an on-vehicle device unit and a car navigation system unit that outputs toll gate information and carrier frequency information to the on-vehicle device unit, The car navigation system unit is a GP
Equipped with an S receiver, a vibration gyro sensor, and an electronic map,
The GPS receiver, the vibration gyro sensor, and the electronic
Vehicle position of the vehicle using information obtained from the map
How the vehicle travels through the detection and route search functions
To the point where the roadside wireless device is installed, such as a tollgate
When the vehicle approaches, the toll gate information is output and
When both enter a specific driving lane such as the toll gate,
The communication zone formed by the roadside wireless device in the driving lane.
Carrier frequency is one of the two carrier frequencies
It is a deviation, that is, the carrier frequency of A mode
Or carrier frequency of B mode
Carrier frequency in either A mode or B mode
Information is output as the carrier frequency information, and the vehicle-mounted device section receives the toll gate information and the carrier frequency information output from the car navigation system section, and the DSRC wireless communication of the vehicle-mounted apparatus section is performed. A carrier frequency is previously matched with a carrier frequency of a communication zone formed by the roadside wireless device, and when the vehicle enters the communication zone, DSRC wireless communication is performed with the roadside wireless device with the matched carrier frequency. Characterize.

In addition, the vehicle-mounted device part includes an antenna part and a transmitter part.
A receiver / modulator / demodulator, a control processor, an ETC processor,
Human machine interface and security module
Module part, IC card interface part, toll booth
It consists of an information acquisition unit and a carrier frequency information acquisition unit.
The antenna part is transmitted from the transmitter / receiver / modulator / demodulator.
The generated signal is converted into an RF (Ra signal with a carrier frequency of 5.8 GHz band).
As a radio frequency (radio frequency) signal
It transmits to the roadside wireless device, and
Receives RF signal of carrier frequency 5.8GHz band from
The transmitter / receiver / modulator / demodulator,
The modulation / demodulation unit outputs a carrier wave frequency of 5.8 GH from the antenna section.
The z-band RF signal is received and demodulated, and the control processing is performed.
To receive data from the control processing unit,
After performing ASK modulation with a carrier frequency of 5.8 GHz,
The control processing unit sends the data to the antenna unit.
・ Manchester decoding and frame decoding of the signal received from the modulator / demodulator
Performs frame synchronization, error detection, etc., and sends it to the ETC processing unit.
Output and receive the data sent from the ETC processing unit.
Trust and calculate Manchester encoding and error detection code
In addition, the signal is sent to the transmitter / receiver / modulator / demodulator, and the carrier wave
Frequency setting processing is performed, and the ETC processing unit
It mainly creates and analyzes various transmission / reception data necessary for
It has a barrel function and sends and receives data with the control processing unit.
Trust and the security module section and the human
The interface required to send and receive data to and from the machine interface
Interface processing, and the human machine interface
The base unit displays the information obtained from the ETC processing unit or
A sound alerts the occupant of the vehicle to the security module.
Of the roadside device and IC card
Certificate, decryption of encrypted data, encryption of plaintext data, E above
Performs processing such as data transmission / reception with the TC processing unit, and
The card interface unit is in the insertion state of the IC card.
Detection and the IC card and the security module
Interface processing with
The profit section is the fee from the car navigation system section.
If you receive the information on the toll gate and the information on the toll gate,
The TC processing unit is notified of that fact and the carrier frequency information is sent.
The information acquisition unit is located in front of the car navigation system unit.
The carrier frequency information is received and sent to the control processing unit.
It is characterized by notifying .

Further, the control processing unit is configured to control the carrier frequency.
Frequency of A mode and B mode to use for number setting process
Stores numerical data and sends it from the onboard unit
The transmission data and the reception data received by the vehicle-mounted device are
Memory and the carrier frequency information acquisition unit.
When receiving the knowledge, the frequency data from the memory
Frequency data of either A mode or B mode in
Memory access block that controls the reading of
A mode or B of the frequency data in the memory
The frequency data of one of the modes is sent to the transmitter / receiver
Frequency setting block for setting the adjustment section, and the memory
To the transmitter of the transmitter / receiver / modulator / demodulator.
The transmission block to be sent and the reception / transmission / modulation / demodulation unit reception
Receiving data from the receiver and storing the received data in the memory.
And a receiving block that stores the
The modulation / demodulation unit transmits from the transmission block of the control processing unit.
Modulates the emitted data and sends it to the antenna section.
The data is received from the transmitter and the antenna and demodulated before
The receiving unit for sending to the receiving block of the control processing unit
And the frequency setting block of the control processing unit.
Based on the determined frequency data, the transmitter and the receiver
Equipped with a local oscillator that supplies a local oscillation frequency signal
E, the transmitter and the receiver are from the local oscillator.
Depending on the local oscillation frequency signal supplied, the transmission data
It is characterized by performing modulation or demodulation of received data or received data .

In addition, the on- board device for the ETC system is installed.
The above-mentioned vehicle is a roadside radio such as a toll gate on a toll road.
Driving far from the point where the device is installed
The vehicle-mounted device is in a sleep mode,
When approaching the point where the roadside device is installed
In terms of the fee from the car navigation system section
The vehicle-mounted device section is shifted to an operation mode in response to the location information .

Further, the car navigation system
The roadside radio is connected to the toll booth in the traveling direction of the vehicle.
When the vehicle approaches the point where the device is installed,
The toll gate information is sent to the toll gate information acquisition unit of the vehicle-mounted device unit.
Then, the toll gate information acquisition unit transmits the toll gate information.
When received, it sends an interrupt signal to the ETC processing unit.
The ETC processing unit that has issued and received the interrupt signal
If the onboard unit is in sleep mode,
Switch the in-vehicle device section to the operation mode, and
The carrier frequency from the car navigation system section
In preparation for receiving the number information, the carrier frequency information acquisition unit
Of the car navigation system
The system department of the specific driving lane such as the toll gate
The carrier frequency of the communication zone is specified to specify the carrier frequency.
When the information is output, the carrier frequency information is output to the vehicle-mounted device.
The carrier frequency information acquisition unit of the control unit
The control is performed by notifying the memory access block of the processing unit.
The carrier frequency setting process of the processing unit is started, and
Access block is in notified A mode or B mode
The carrier frequency of the from the frequency data in the memory
Select the frequency setting block and set the frequency
The setting block transmits the set carrier frequency.
Set to the local oscillator of the receiver / modulator / demodulator,
The carrier frequency set in the transmitter is the transmitter / receiver unit.
・ Local oscillation frequency for the transmitter and the receiver of the modulator / demodulator
Supplied as a number signal, the transmitter and receiver are
It is possible to operate in synchronization with the carrier frequency of the roadside device.
Characterized in that that.

In addition, it is arranged at a plurality of points on the road network.
Roadside wireless device and ETC system of the present invention installed in a vehicle
System on-board device and information from the roadside wireless device
Management center and the vehicle is connected to the road network.
On the road network of the vehicle when traveling above
A display device of the management center showing the traveling position and the traveling locus.
It is characterized in that it is possible to construct a vehicle traveling locus management system that is displayed on , for example.

[0017]

[0018]

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an on-vehicle device for a non-stop automatic charge collection (ETC) system of the present invention.

The ETC system vehicle-mounted device 40 according to the present embodiment shown in FIG. 1 includes a vehicle-mounted device unit 50 and a car navigation system unit 70 that outputs toll gate information 80 and carrier frequency information 90 to the vehicle-mounted device unit 50. It consists of and.

The vehicle-mounted device unit 50 receives the toll gate information 80 and the carrier frequency information 90 output from the car navigation system unit 70, and the roadside wireless device forms the carrier frequency of the DSRC wireless communication of the vehicle-mounted device unit 50. The carrier frequency of the communication zone is matched, and the matched carrier frequency is used for wireless communication with the roadside apparatus.

FIG. 2 is an image diagram of wireless communication between the vehicle-mounted device for ETC system and the roadside wireless device to which the present invention is applied.

In FIG. 2, the on-vehicle device 4 for the ETC system
A vehicle 101 equipped with 0 is traveling along a traveling lane 103 such as a tollgate in a traveling lane. Roadside wireless devices 105 are installed at necessary places such as toll booths.
The roadside wireless device 105 includes the communication control unit 106 and the structure 10.
4 and a wireless unit 107 attached to the No. 4 unit. On-board device 4 for ETC system mounted on vehicle 101
0 and the wireless unit 107 of the roadside wireless device 105 are connected to the vehicle 10
1 performs DSRC wireless communication 108 while passing through a communication zone such as a tollgate. The main function of the roadside apparatus 105 is that the communication control unit 106 controls highly-reliable cryptographic communication and mutual authentication, and the wireless unit 107 performs data modulation / demodulation and transmission / reception control in DSRC wireless communication. Data such as vehicle information, contract information, toll gate information, lane / route information, toll collection information, etc. are transmitted and received between the ETC system vehicle-mounted device 40 and the roadside apparatus 105.

FIG. 3 is a diagram showing an example of carrier frequency allocation for DSRC wireless communication in each traveling lane such as in a tollgate.

In FIG. 3, when there are a plurality of traveling lanes of a vehicle, the roadside wireless device must not perform wireless communication with the vehicle-mounted device of the vehicle in the adjacent lane according to the DSRC wireless communication standard. That is, the driving lane 12
At 0, a communication zone 110 is formed by the wireless section 107 of the roadside wireless device attached to the structure 104, and similarly at the traveling lane 121, a communication zone 111 is formed.
A communication zone 112 is similarly formed in the traveling lane 122. In each communication zone, two different carrier frequencies, A mode and B mode, are used to prevent DRC radio communication interference with adjacent lanes.
It is supposed to perform SRC wireless communication. Communication zone 1
10 is in A mode, so its adjacent communication zone 1
11 uses B mode, and communication zone 1 next to it
12 uses the carrier frequency of the A mode.

The carrier frequency in A mode is transmission = 5.795 GHz and reception = 5.835 GHz, and the carrier frequency in B mode is transmission = 5.80.
5 GHz, reception = 5.845 GHz.

FIG. 4 is a diagram showing a communication function in ETC DSRC wireless communication.

In DSRC wireless communication for ETC, OSI (Open Systems Interc) is used.
connection: the communication functions of the first layer (physical layer), the second layer (data link layer), and the seventh layer (application layer) defined by the open type inter-system interconnection). The ETC application layer function and the security module layer function are also mounted in the seventh layer application layer.

FIG. 5 is a diagram showing an outline of the communication standard of the DSRC wireless communication for ETC.

In FIG. 5, the frequency band of DSRC wireless communication is 5.8 GHz band, and the communication system adopts an active system in which both the vehicle-mounted device and the roadside wireless device have a transmitter to transmit radio waves. The modulation method is ASK (Amplit
ude Shift Keying (amplitude shift keying) system, encoding system is Manchester system, and modulation signal speed is 1
It is said to be Mbps.

FIG. 6 is a block diagram showing the construction of the vehicle-mounted device for ETC system of the present invention.

In FIG. 6, the vehicle-mounted device section 50 includes an antenna section 51, a transmission / reception section / modulation / demodulation section 52, and a control processing section 53.
, ETC processing unit 54, human machine interface unit 55, security module unit 56, IC
Card interface unit 57 and toll gate information acquisition unit 59
And a carrier frequency information acquisition unit 60.

The antenna section 51 corresponds to the first layer of the communication function of the DSRC wireless communication, and transmits the signal transmitted from the transmission / reception section / modulation / demodulation section 52 to the RF (R) of the carrier frequency 5.8 GHz band.
It is transmitted to the roadside apparatus as an audio frequency (radio frequency) signal. In addition, an RF signal having a carrier frequency of 5.8 GHz is received from a roadside wireless device,
It is sent to the transmission / reception unit / modulation / demodulation unit 52.

The transmitting / receiving unit / modulation / demodulation unit 52 includes an antenna unit 51.
Corresponding to the first layer of the communication function of the DSRC wireless communication similarly to the above, from the antenna section 51 to the R of the carrier frequency of 5.8 GHz band.
The F signal is received, demodulated and sent to the control processing unit 53. Further, it receives data from the control processing unit 53, carries out ASK modulation of the carrier frequency of 5.8 GHz band, and then sends it to the antenna unit 51.

The control processing unit 53 corresponds to the second layer / seventh layer of the communication function of the DSRC wireless communication, performs Manchester decoding of the signal received from the transmitting / receiving unit / modulation / demodulation unit 52, frame synchronization, error detection, etc. It is sent to the ETC processing unit 54. It also receives the data sent from the ETC processing unit 54, calculates and adds Manchester coding and error detection code, and sends it to the transmission / reception unit / modulation / demodulation unit 52. Further, a carrier frequency setting process described later is performed.

The ETC processing unit 54 corresponds to the seventh layer (application layer) of the communication function of DSRC wireless communication, and is E
The main function is to create and analyze various transmission / reception data required for TC, and is also required for data transmission / reception with the seventh layer of the control processing unit 53 and data transmission / reception with the security module unit 56 and the human-machine interface unit 55. Interface processing.

Human machine interface section 55
Notifies the occupants of the vehicle of the following information by display or sound. That is, when the power of the vehicle-mounted device section 50 is turned on and when the IC card 58 is used.
Self-diagnosis result of the vehicle-mounted device section 50 at the time of insertion, instruction information from the roadside wireless device to the vehicle-mounted device section 50, communication error information,
It includes a toll, an IC card writing completion notification, and vehicle-mounted device abnormality information.

The security module section 56 performs processing such as mutual authentication with the roadside wireless device and the IC card 58, decryption of encrypted data, encryption of plaintext data, and data transmission / reception with the ETC processing section 54.

The IC card interface section 57 is an IC
It detects the insertion state of the card 58 and performs interface processing between the IC card 58 and the security module unit 56.

The IC card 58 stores vehicle information, contract information, fee collection information, etc. specific to each vehicle, which is necessary for ETC processing.

The tollgate information acquisition unit 59 indicates from the car navigation system unit 70 that the vehicle has approached a point such as a tollgate where a roadside wireless device is installed.
When 0 is received and the tollgate information 80 is received, the ETC processing unit 54 is notified of that fact.

The carrier frequency information acquisition unit 60 receives the carrier frequency information 90 of the communication zone formed by the roadside wireless device such as a tollgate from the car navigation system unit 70 and notifies the control processing unit 53 of this. Control processing unit 53
By receiving the carrier frequency information 90, the carrier frequency setting processing of the vehicle-mounted device 50 can be performed.

Next, the configuration of the car navigation system section 70 of FIG. 6 will be described.

The present invention is characterized in that the car navigation system section 70 uses an existing car navigation system.

In other words, the car navigation system unit 70 uses a GPS (Global Positionin).
g System) G receiving positioning data from satellite
A PS receiving antenna 71, a GPS receiver 72 that receives and analyzes positioning data from the GPS receiving antenna 71, and a vibration gyro sensor 73 for correcting the positioning data.
And a CD-ROM (Compact Disk-Rea)
d Only Memory) or DVD (Dig
CD-ROM / DVD drive circuit 74 that reads an electronic map stored in the digital video disk 79, positioning data from the GPS receiver 72, data from the vibration gyro sensor 73, and CD-ROM / DV.
Using the electronic map from the D drive circuit 74, the control CPU 75 that detects the vehicle position of the vehicle and outputs the tollgate information 80 and the carrier frequency information 90, the memory 76 used by the control CPU 75, and the control CPU The drawing unit 77 draws the detected vehicle position as a screen, and the display unit 78 displays the screen drawn by the drawing unit 77.

The electronic map stored in the CD-ROM / DVD 79 contains map information about toll road networks and toll gates, and for each running lane at a point where a roadside wireless device such as a toll gate is installed. It is assumed that all the information about the carrier frequency is stored.

Next, referring to FIG. 7, the transmitter / receiver / modulator / demodulator 52 and the control processor 53 of the vehicle-mounted device 50 shown in FIG.
The detailed configuration of will be described.

FIG. 7 is a diagram showing the detailed structure and mutual interface of the transmission / reception unit / modulation / demodulation unit and control processing unit of the vehicle-mounted device.

In FIG. 7, components corresponding to those shown in FIG. 6 are designated by the same reference numerals or symbols, and the description thereof will be omitted.

In FIG. 7, the control processing unit 53 stores the frequency data 5311 of the A mode and the B mode for use in the carrier frequency setting process, and the on-vehicle device section 50.
A memory 531 for storing transmission data 5312 transmitted from the vehicle and reception data 5313 received by the vehicle-mounted device section 50.
When a notification is received from the carrier frequency information acquisition unit 60, the memory access block 532 for controlling the reading of the frequency data of either the A mode or the B mode in the frequency data 5311 from the memory 531 and the memory 531 of the memory 531. It comprises a frequency setting block 533 for setting the frequency data of either the A mode or the B mode in the frequency data 5311 in the transmission / reception unit / modulation / demodulation unit 52. Frequency data 531 in memory 531
1 is set in the local oscillator 521 of the transmission / reception unit / modulation / demodulation unit 52.

Further, the control processing unit 53 receives data from the transmission block 5335 of the transmission data 5312 of the memory 531 to the transmission unit 522 of the transmission / reception unit / modulation / demodulation unit 52 and the reception unit 523 of the transmission / reception unit / modulation / demodulation unit 52. Memory 5
31 and a reception block 536 stored as reception data 5313.

The transmission / reception unit / modulation / demodulation unit 52 includes a control processing unit 5
The transmitting unit 522 that modulates the data transmitted from the transmission block 535 of No. 3 and transmits to the antenna unit 51, and the antenna unit 5
1. The receiving unit 523 that receives the data from 1, demodulates it, and sends it to the receiving block 536 of the control processing unit 53;
3, a local oscillator 521 for supplying a local oscillation frequency signal to the transmitting section 522 and the receiving section 523 based on the frequency data set by the frequency setting block 533 of FIG.

The transmitting unit 522 and the receiving unit 52 described above.
3 is configured to modulate or demodulate transmission data or reception data by a local oscillation frequency signal supplied from the local oscillator 521. Therefore, by setting the same carrier frequency as the carrier frequency transmitted by the roadside wireless device in the local oscillator 521, wireless communication between the roadside wireless device and the vehicle-mounted device unit 50 becomes possible.

Next, with reference to FIG. 8, a more detailed configuration of the transmission / reception unit / modulation / demodulation unit 52 of the vehicle-mounted device 50 shown in FIG. 7 will be described.

FIG. 8 is a diagram showing a more detailed structure of the transmission / reception unit / modulation / demodulation unit of the vehicle-mounted device.

In FIG. 8, components corresponding to those shown in FIG. 7 are designated by the same reference numerals or symbols, and their description will be omitted.

In FIG. 8, the transmission unit 522 of the transmission / reception unit / modulation / demodulation unit 52 is the transmission block 535 of the control processing unit 53.
IF (Intermedia) that performs interface processing with
ate Frequency (intermediate frequency) amplifier 52
23, a mixer 5222 that modulates the output signal of the IF amplifier 5223, and an RF amplifier 5221 that buffers the output signal of the mixer 5222 and sends it to the antenna section 51.

Transmitter / receiver / receiver 523 of modem 52
Is an RF amplifier 5231 that buffers the RF signal input from the antenna section 51, a mixer 5232 that demodulates the output signal of the RF amplifier 5231, and a mixer 5232.
And an IF amplifier 5233 that sends the output signal of the above to the receiving block 536 of the control processing unit 53.

Since the local oscillation frequency signal from the local oscillator 521 is supplied to the mixer 5222 and the mixer 5232, the transmission section 522 and the reception section 523 are tuned to the carrier frequency of the roadside apparatus to perform DSRC wireless communication. It becomes possible to do.

Next, referring again to FIGS. 6 and 7, the carrier frequency setting process of the ETC system vehicle-mounted device of the present invention will be described in detail.

When the vehicle equipped with the on-board device for the ETC system approaches a point where a roadside wireless device is installed, such as a toll gate on a toll road, the car navigation system section 70 of the on-board device for the ETC system of the vehicle uses a GPS satellite. The presence of a tollgate in the traveling direction is detected by the own vehicle position detection function and the route search function using the, and the tollgate information 80 is transmitted to the tollgate information acquisition section 59 of the vehicle-mounted device section 50. Upon receiving the toll gate information 80, the toll gate information acquisition unit 59 sends an interrupt signal to the ETC processing unit 54.
The ETC processing unit 54 that has received this interrupt signal shifts the vehicle-mounted device unit 50 to the operation mode when the vehicle-mounted device unit 50 is in the sleep mode. With this function, the vehicle-mounted device unit 50 can enter the sleep mode as a power saving measure when traveling on a normal road where no roadside wireless device is installed.

Upon receiving the interrupt signal from the tollgate information acquisition unit 59, the ETC processing unit 54 receives the carrier frequency information 90 from the car navigation system unit 70 at the next time point.
In preparation for reception of the information, the carrier frequency information acquisition unit 60, which is an interface with the car navigation system unit 70, is monitored for information reception.

The car navigation system section 70 is C
Using the electronic map obtained from the D-ROM / DVD drive circuit 74, the carrier frequency information of the roadside wireless device of each traveling lane at the toll gate in the traveling direction of the vehicle is stored in the CD-ROM /
It is read from the DVD 79 and stored in the internal memory 76.

The car navigation system section 70 corrects the positioning data from the GPS receiver 72 by the output of the vibration gyro sensor 73 and the electronic map of the CD-ROM / DVD 79 when the vehicle enters an arbitrary traveling lane of the tollgate. Then, it is accurately determined which lane the vehicle will enter. The car navigation system unit 70 specifies the carrier frequency of the communication zone formed in the traveling lane in which the vehicle is about to enter based on the information of the traveling lane in which the vehicle is about to enter, and acquires the carrier frequency information of the vehicle-mounted device unit 50. The carrier frequency information 90 is written in the unit 60.
The writing format is, for example, "1" for the carrier frequency in the A mode and "0" for the carrier frequency in the B mode.
And The operation of writing the carrier frequency information 90 into the carrier frequency information acquisition unit 60 is completed before the vehicle enters the communication zone formed in the traveling lane in which the vehicle is about to enter.

Carrier frequency information acquisition section 6 of vehicle-mounted device section 50
0 notifies the memory access block 532 of the control processing unit 53 of the carrier frequency information 90 to start the carrier frequency setting process of the control processing unit 53, and the memory access block 532 notifies the carrier frequency of the notified A mode or B mode. Is selected from the frequency data 5311 in the memory 531 and set in the frequency setting block 533.

The frequency setting block 533 transmits the set carrier frequency to the local oscillator 5 of the transmitter / receiver / modulator / demodulator 52.
Set to 21. Since the carrier frequency set in the local oscillator 521 is supplied to the transmitter 522 and the receiver 523 of the transmitter / receiver / modulator / demodulator 52 as a local oscillator frequency signal, the transmitter 522 and the receiver 523 are carriers of the roadside apparatus. The vehicle can enter the communication zone because it can be operated in synchronism with the frequency, and the time when it can be operated is before the vehicle enters the communication zone formed in the driving lane where the vehicle is about to enter. After that, it becomes possible to perform the wireless communication necessary only for ETC.

Next, the on-vehicle device for ETC system of the present invention described with reference to FIGS. 6 and 7 and the conventional general ETC
In order to compare the frequency selecting means of the vehicle-mounted device for vehicle, a conventional general ETC vehicle-mounted device and its frequency selecting means will be described with reference to FIGS. 9 and 10.

FIG. 9 is a diagram showing a system configuration example of a conventional general ETC vehicle-mounted device.

In FIG. 9, the vehicle-mounted device 10 includes an antenna 1
, A transmitter / receiver / modulator / demodulator 2, a control processor 3, and an ETC
A processing unit 4, a human-machine interface unit 5,
It is composed of a security module section 6 and an IC card interface section 7.

The antenna section 1 corresponds to the first layer of the communication function of the DSRC wireless communication, and the signal transmitted from the transmission / reception section / modulation / demodulation section 2 is transmitted to the roadside apparatus as an RF signal having a carrier frequency of 5.8 GHz. Send. In addition, an RF signal having a carrier frequency of 5.8 GHz is received from a roadside wireless device,
It is sent to the transmission / reception unit / modulation / demodulation unit 2.

The transmission / reception unit / modulation / demodulation unit 2 corresponds to the first layer of the communication function of the DSRC wireless communication similarly to the antenna unit 1, receives the RF signal of the carrier frequency of 5.8 GHz band from the antenna unit 1 and demodulates it. Then, it is sent to the control processing unit 3. or,
The data is received from the control processing unit 3, and the carrier frequency is 5.8.
After performing ASK modulation in the GHz band, it is sent to the antenna section 1.

The control processing unit 3 corresponds to the second layer and the seventh layer of the communication function of the DSRC wireless communication, and corresponds to the transmission / reception unit / modulation / demodulation unit 2.
Manchester decoding of received signals, frame synchronization,
Error detection is performed and the result is sent to the ETC processing unit 4. or,
The data sent from the ETC processing unit 4 is received, and Manchester encoding and error detection code are calculated / added and sent to the transmission / reception unit / modulation / demodulation unit 2. Further, a frequency selection process described later is performed.

The ETC processing unit 4 corresponds to the seventh layer (application layer) of the communication function of DSRC wireless communication,
The main function is to create and analyze various transmission / reception data required for C, and is also required for data transmission / reception with the seventh layer of the control processing unit 3 and data transmission / reception with the security module unit 6 and the human-machine interface unit 5. Interface processing.

The human machine interface section 5 is
Display or sound the following information to notify the vehicle occupants. That is, the self-diagnosis result of the vehicle-mounted device 10 when the vehicle-mounted device 10 is powered on and when the IC card 8 is inserted, instruction information from the roadside wireless device to the vehicle-mounted device 10, communication error information, toll, I
The notification includes C card writing completion notification and vehicle-mounted device abnormality information.

The security module unit 6 performs processing such as mutual authentication with the roadside apparatus and the IC card 8, decryption of encrypted data, encryption of plaintext data, and data transmission / reception with the ETC processing unit 4.

The IC card interface section 7 detects the insertion state of the IC card 8 and performs interface processing between the IC card 8 and the security module section 6.

Next, with reference to FIG. 10, detailed functions of the transmitting / receiving unit / modulation / demodulation unit 2 and the control processing unit 3 of the vehicle-mounted device 10 shown in FIG. 9 and the details of the operation of the frequency selection process in the vehicle-mounted device 10 will be described. explain.

FIG. 10 is a diagram showing detailed functional blocks and mutual interfaces of a transmission / reception unit / modulation / demodulation unit and a control processing unit of a conventional general ETC vehicle-mounted device.

Incidentally, in FIG. 10, the components corresponding to those shown in FIG. 9 are designated by the same reference numerals or symbols, and the description thereof will be omitted.

In FIG. 10, the control processing unit 3 stores the frequency data 311 in the A mode and the B mode for use in the frequency selection processing, and receives the transmission data 312 transmitted from the vehicle-mounted device and the vehicle-mounted device. Received data 313
For storing the frequency data 311 from the memory 31, a memory access block 32 for controlling reading of the frequency data 311 from the memory 31,
A frequency setting block 33 for setting in the modulator / demodulator 2,
The timer 34 is configured to periodically instruct the frequency setting process for the frequency selection process. The frequency data 311 of the memory 31 is set in the local oscillator 21 of the transmission / reception unit / modulation / demodulation unit 2.

Further, the control processing unit 3 receives data from the transmission block 35 for transmitting the transmission data 312 of the memory 31 to the transmission unit 22 of the transmission / reception unit / modulation / demodulation unit 2 and the reception unit 23 of the transmission / reception unit / modulation / demodulation unit 2. The reception block 36 stores the reception data 313 in the memory 31 and the unique word determination block 37 that detects a unique word required for frequency selection processing from the data of the reception section 23 of the transmission / reception section / modulation / demodulation section 2. It is configured.

The transmitting / receiving unit / modulation / demodulation unit 2 also modulates the data transmitted from the transmission block 35 of the control processing unit 3 and transmits the data to the antenna unit 1, and receives and demodulates the data from the antenna unit 1. Then, the reception block 3 of the control processing unit 3
6, and a local oscillator 21 that supplies a local oscillator frequency signal to the transmitter 22 and the receiver 23 based on the frequency data set by the frequency setting block 33 of the control processor 3. It consists of

Further, the transmission / reception unit / modulation / demodulation unit 2 uses the DSR
In order to detect whether or not it has entered the communication zone of the C wireless communication, the electric field level detection circuit 24 for detecting the received electric field level of the signal from the antenna section 1 and the electric field level detection circuit 24 define the communication zone of the DSRC wireless communication. If detected, ET
Interrupt circuit 2 for generating an interrupt signal to C processing unit 4
It is composed of 5 and. The interrupt signal generated by the interrupt circuit 25 is given to the ETC processing unit 4 and used as a trigger for starting the DSRC wireless communication.

The operation of the frequency selection processing in the conventional general ETC vehicle-mounted device shown in FIG. 10 is performed as follows.

When the vehicle is traveling on a normal road, that is, outside the communication zone of the DSRC radio communication, the timer 34 inside the control processing unit 3 operates, and the frequency setting block 33 and the memory access block 32 are displayed at regular intervals. Make an interrupt. Due to this interruption, the memory access block 32 reads out frequency data different from the frequency data read out in the immediately preceding interruption from the memory 31, and sets it in the frequency setting block 33.
Send to. For example, if the previously read frequency data is in A mode, the data transmitted this time is in B mode. In the case of the B mode last time, it is the A mode this time. The frequency setting block 33 operates in A mode / at every interruption from the timer 34.
The frequency data is alternately set in the B mode in the local oscillator 21 of the transmission / reception unit / modulation / demodulation unit 2. As a result, the transmission / reception unit / modulation / demodulation unit 2 operates so as to periodically tune to the carrier wave in the A mode or the B mode, and searches for a radio signal of the roadside apparatus.

When the vehicle enters the communication zone of the DSRC wireless communication, the transmission data from the roadside wireless device is transmitted to the antenna section 1.
Is received by the transmission / reception unit / modulation / demodulation unit 2 and input to the control processing unit 3. Roadside wireless devices and conventional general E
If the frequency of the on-vehicle device for TC is the same, the transmission data from the roadside wireless device is correctly demodulated, and the unique word determination block 37 of the control processing unit 3 determines that the received data has a unique communication frame of DSRC wireless communication. You can check the bit string that represents a word. If the control processing unit 3
When the unique word is confirmed in the unique word determination block 37, the control processing unit 3 determines that it is in synchronization with the roadside wireless device at the carrier frequency set in the frequency setting block 33 at that time, and stops the timer 34. Then, the local oscillator frequency of the local oscillator 21 of the transmitter / receiver / modulator / demodulator 2 is fixed to the frequency at that time. Further, when the vehicle-mounted device detects the unique word of the communication frame of the DSRC wireless communication twice consecutively, the ETC processing unit 4 of the vehicle-mounted device determines that the synchronization between the roadside wireless device and the vehicle-mounted device is established, and the ETC communication processing is performed. Move.

As described with reference to FIGS. 9 and 10,
The conventional general ETC on-vehicle device frequency selecting means has the following problems.

First, in order to realize this frequency selecting means, a timer for setting the frequency for the local oscillator inside the vehicle-mounted device must be built in, and the frequency data switching control must be performed by the timer. That is. As a method of configuring a timer, DSR for ETC is used.
Among the communication functions of C, there are a method of mounting a timer by software on the seventh layer (application layer) and a method of mounting a hardware timer on the second layer (data link layer) by a dedicated logic circuit. In the former case, the scale of software processing tasks increases, and in the latter case, the scale of hardware increases. In any case, there is a problem that the power consumption of the vehicle-mounted device cannot be saved because the scale increases.

Secondly, an electric field level detection circuit and an interrupt circuit in the communication zone are required in the transmission / reception section / modulation / demodulation section of the vehicle-mounted device.

Thirdly, in the initial operation of the DSRC wireless communication, at least one of the communication frames is detected in order to detect the unique word of the communication frame of the DSRC wireless communication.
Since it is necessary to use the frame to confirm the matching of the carrier frequency, the number of communication frames used for the original wireless communication processing for ETC is reduced, and the wireless communication is time-limited. is there.

As described above, in the vehicle-mounted device for the ETC system of the present invention, the position information and carrier frequency of the tollgate and roadside wireless device are recognized by using the function of the existing car navigation system. The following circuits and functions required in the conventional general ETC vehicle-mounted device are not required, and the circuit of the ETC vehicle-mounted device system can be simplified, the power consumption can be saved, and the load of wireless communication processing can be reduced.

First, when the vehicle approaches the toll gate, an interrupt is input from the car navigation system, so the electric field level detection circuit and interrupt circuit of the conventional transmitter / receiver / modulator / demodulator are not required, and the transmitter / receiver / modulator / demodulator is not required. It is possible to reduce the size and cost of the parts. In addition, the ETC on-vehicle device unit can normally be in the sleep mode, which enables power saving of the on-vehicle device unit.

Secondly, since the carrier frequency of the roadside radio device of the traveling lane where the vehicle is about to enter is obtained from the car navigation system, the frequency selecting means required for the conventional general on-vehicle device for ETC is unnecessary. Becomes Then, the function of the software timer or the hardware timer by the dedicated logic circuit which is necessary for realizing the frequency selecting means can be reduced, and the power saving of this part can be achieved.

Thirdly, in the conventional general on-vehicle device for ETC, in order to perform tuning control and synchronization establishment between the on-vehicle device and the roadside wireless device,
At least one communication frame must be used,
According to the present invention, the vehicle-mounted device can know the carrier frequency of the communication zone in advance and can enter the communication zone by tuning the carrier frequency. Therefore, an extra communication frame that can be used for wireless communication is secured as compared with the conventional case. Can do things,
The load of wireless communication processing is reduced.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 11 is a diagram for explaining the second embodiment of the present invention.

Referring to FIG. 11, the vehicle-mounted device 41 for running trajectory management differs from the vehicle-mounted device 40 for ETC system of the first embodiment of the present invention shown in FIG. 1 in the following points.

That is, the tollgate information 8 output from the car navigation system section 70 to the vehicle-mounted device section 50.
The difference is that 0 is replaced by the checkpoint information 81.

The checkpoint information 81 is information indicating that the vehicle is approaching a checkpoint on the road, in addition to the tollgate information 80 indicating that the vehicle is approaching the tollgate. Roadside wireless devices are installed at checkpoints on the road so that it is possible to know which checkpoint the vehicle has passed. Therefore, every time the vehicle equipped with the vehicle-mounted device 41 for traveling locus management passes the checkpoint on the road, the roadside wireless device and the DSR are connected.
Since C wireless communication is performed, it is possible to grasp the traveling locus of the vehicle. However, the CD-RO used by the car navigation system unit 70 of the vehicle-mounted device 41 for running trajectory management
It is assumed that the M / DVD stores all map information about road networks and checkpoints on the road, and information about carrier frequencies for each traveling lane in which roadside wireless devices such as checkpoints are installed.

By mounting the traveling locus management vehicle-mounted device 41 on the vehicle, the traveling position and traveling locus of the transportation vehicle can be displayed on a display device of a separately installed management center for collecting information of the roadside wireless device. To let the transportation company know the transportation vehicle traveling management system to improve collection and delivery efficiency and transportation efficiency, or to display the traveling records of special vehicles on the display device of a separately installed management center, etc. It is possible to build a vehicle travel locus management system such as the special vehicle travel record management system provided.

[0102]

As described above, the vehicle-mounted device for the ETC system of the present invention has the effect that the circuit scale and the software scale of the vehicle-mounted device portion are small, so that it is possible to save power, and the DSRC radio This has the effect that communication frames for communication can be used to the maximum in ETC communication processing.

[Brief description of drawings]

FIG. 1 Non-stop automatic toll collection (ETC) of the present invention
It is a block diagram showing one embodiment of an in-vehicle device for systems.

FIG. 2 is an image diagram of wireless communication between an on-board device for an ETC system and a roadside wireless device to which the present invention is applied.

[Figure 3] DSRC in each driving lane such as inside the toll gate
It is a figure which shows an example of allocation of the carrier frequency of wireless communication.

FIG. 4 is a diagram showing a communication function in DSRC wireless communication for ETC.

FIG. 5 is a diagram showing an outline of communication standards of DSRC wireless communication for ETC.

FIG. 6 is a block diagram showing a configuration of an on-vehicle device for ETC system of the present invention.

FIG. 7 is a diagram showing a detailed configuration and a mutual interface of a transmission / reception unit / modulation / demodulation unit and a control processing unit of the vehicle-mounted device unit.

FIG. 8 is a diagram showing a more detailed configuration of a transmission / reception unit / modulation / demodulation unit of the vehicle-mounted device unit.

FIG. 9 is a diagram showing a system configuration example of a conventional general ETC vehicle-mounted device.

FIG. 10: Transmitter / receiver unit of a conventional general ETC vehicle-mounted device
It is a figure which shows the detailed functional block and mutual interface of a modulation / demodulation part and a control processing part.

FIG. 11 is a diagram illustrating a second embodiment of the present invention.

[Explanation of symbols]

1 Aerial section 2 Transmitter / receiver / modulator / demodulator 21 Local oscillator 22 Transmitter 23 Receiver 24 Electric field level detection circuit 25 interrupt circuit 3 Control processing unit 31 memory 311 Frequency data 312 transmission data 313 Received data 32 memory access blocks 33 Frequency setting block 34 timer 35 Send block 36 receive blocks 4 ETC processing unit 5 Human machine interface 6 Security module section 7 IC card interface 8 IC card 10 Onboard equipment 40 ETC system onboard equipment 41 On-vehicle device for running trajectory management 50 On-board equipment 51 Aerial part 52 Transmitter / receiver / modulator / demodulator 521 Local oscillator 522 transmitter 5221 RF amplifier 5222 mixer 5223 IF amplifier 523 Receiver 5231 RF amplifier 5232 mixer 5233 IF amplifier 53 Control processing unit 531 memory 5311 Frequency data 5312 Transmission data 5313 Received data 532 memory access block 533 Frequency setting block 535 transmission block 536 receive block 54 ETC processing unit 55 Human Machine Interface 56 Security Module Department 57 IC card interface 58 IC card 59 Toll Gate Information Acquisition Department 60 Carrier frequency information acquisition unit 70 Car Navigation System Department 71 GPS receiving antenna 72 GPS receiver 73 Vibration gyro sensor 74 CD-ROM / DVD drive circuit 75 Control CPU 76 memory 77 Drawing unit 78 Display 79 CD-ROM / DVD 80 tollgate information 90 Carrier frequency information 101 vehicle 103 Vehicle traveling direction 104 structure 105 Roadside wireless device 106 communication control unit 107 wireless unit 108 DSRC wireless communication 110 communication zone 111 Communication Zone 112 communication zone 120 driving lanes 121 Driving lane 122 Driving lane

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI G08G 1/09 G08G 1/09 F 1/0967 1/0967 (58) Fields investigated (Int.Cl. ⁷ , DB name) G07B 15/00 510 G07B 15/00 G01C 21/00 G01S 5/14 G01S 13/91 G08G 1/09 G08G 1/0967

Claims (6)

(57) [Claims] 1. A short-distance communication (DSRC: Dedicated Sh) that is mounted on a vehicle and communicates with a roadside wireless device.
Non-stop automatic toll collection (ETC: Electr) that performs ort Range Communication
The on-vehicle device for an onic toll collection system, wherein the on-vehicle device for the ETC system includes an on-vehicle device unit and a car navigation system unit that outputs toll gate information and carrier frequency information to the on-vehicle device unit. , The car navigation system section,
Equipped with GPS receiver, vibration gyro sensor and electronic map
The GPS receiver, the vibration gyro sensor, and the
Vehicle of the vehicle using information obtained from the electronic map
With the position detection function and route search function,
The roadside devices such as toll gates are installed in the row direction
When the vehicle approaches the point, the toll gate information is output and
When the vehicle enters a specific driving lane such as the toll gate,
The communication formed by the roadside wireless device in the traveling lane.
The carrier frequency of the signal zone is one of the two carrier frequencies
Which of the two is the carrier frequency of A mode
Or the B-mode carrier frequency is specified.
Carrier frequency in either specified A mode or B mode
The wave number information is output as the carrier frequency information, and the vehicle-mounted device section receives the toll gate information and the carrier frequency information output from the car navigation system section, and the DSRC wireless communication of the vehicle-mounted device section is performed. Of the carrier frequency of the roadside wireless device is previously matched with the carrier frequency of the communication zone formed by the roadside wireless device, and DSRC wireless communication is performed with the roadside wireless device using the matched carrier frequency when the vehicle enters the communication zone. On-board device for non-stop automatic toll collection (ETC) system. 2. The vehicle-mounted device part includes an antenna part and a transmitting / receiving part.
-The modulation / demodulation unit, the control processing unit, the ETC processing unit, the
Man-machine interface and security module
Section, IC card interface section, toll gate information collection
The acquisition unit and the carrier frequency information acquisition unit,
The antenna part is the signal sent from the transmitter / receiver / modulator / demodulator.
No. of the carrier frequency 5.8 GHz band RF (Radio
Frequency: radio frequency) signal as the roadside
To the wireless device and also from the roadside wireless device
The RF signal having a carrier frequency of 5.8 GHz is received,
Sending to the transmitter / receiver / modulator / demodulator, the transmitter / receiver / modulator / demodulator
Is the R of the carrier frequency 5.8 GHz band from the antenna section.
Receives the F signal, demodulates it, and sends it to the control processing unit.
It also receives data from the control processing unit and
After performing ASK modulation in the wave number 5.8 GHz band, the antenna
And the control processing unit sends the data to the transmitter / receiver / modulator / demodulator.
Manchester decoding of the signal received from the
Period, error detection, etc., and sends it to the ETC processing unit,
Also, receiving the data sent from the ETC processing unit,
Calculate and add Manchester encoding and error detection code
The carrier frequency is sent to the transmitter / receiver / modulator / demodulator.
Performs setting processing, and the ETC processing unit
Main machine for creating and analyzing various necessary transmission / reception data
In addition to the function
Security module section and the human machine
Interface required to send and receive data to and from the interface
The human-machine interface
The section displays the information obtained from the ETC processing section or displays it by sound.
Notifying the vehicle occupant, the security module section
Is the mutual authentication with the roadside device and the IC card,
Data decryption, plaintext data encryption, ETC processing
The IC card is used to perform processing such as data transmission / reception with the science department.
The interface section detects the insertion state of the IC card.
And the IC card and the security module section
Interface processing of the tollgate information acquisition unit
From the car navigation system department to the toll booth
When the information is received and the toll gate information is received, the ETC
Notify the processing unit of that fact and collect the carrier frequency information.
The acquisition unit is used to transport the vehicle from the car navigation system unit.
Receives transmission frequency information and notifies it to the control processing unit
The on- vehicle device for an ETC system according to claim 1, wherein: 3. The control processing unit is a carrier frequency setting process.
Frequency data of A mode and B mode for theoretical use
Store the data and send the data from the on-board unit.
Data and the received data received by the vehicle-mounted device section are stored.
Receives notification from the memory and the carrier frequency information acquisition unit
Of the frequency data from the memory,
Read frequency data in either mode or B mode
Memory access block for controlling output, and the memory
Of the frequency data of A mode or B mode
Set either frequency data in the transmitter / receiver / modulator / demodulator.
Frequency setting block for setting and the transmission of the memory.
Signal data to the transmitter / receiver / modulator / demodulator transmitter
From the transmission block and the reception unit of the transmission / reception unit / modulation / demodulation unit
Data is received and stored in the memory as the received data.
And a receiving block for storing the transmitting / receiving unit / modulation / demodulation unit.
Is transmitted from the transmission block of the control processing unit.
The transmitter for modulating data and transmitting the data to the antenna
And receives the data from the antenna section, demodulates the data, and performs the control.
The receiving unit for sending to the receiving block of the processing unit;
It is set by the frequency setting block of the control processing unit.
Based on the frequency data
A local oscillator for supplying a local oscillation frequency signal,
The transmitter and the receiver are supplied from the local oscillator.
Depending on the local oscillation frequency signal, the transmission data or
The ETC system vehicle-mounted device according to claim 2 , wherein the received data is modulated or demodulated . 4. A vehicle-mounted device for the ETC system is mounted.
If the vehicle is a roadside wireless device such as a tollgate on a toll road
If you are driving a long distance from the installed point,
The vehicle-mounted device is in a sleep mode, and the vehicle is
When approaching the point where the roadside wireless device is installed,
From the car navigation system section to the toll gate information
The vehicle-mounted device for an ETC system according to any one of claims 1 to 3, wherein the vehicle-mounted device unit is shifted to an operation mode in response to the received signal. 5. The car navigation system section,
Installation of the roadside wireless device such as a tollgate in the traveling direction of the vehicle
If the vehicle approaches the point where
Information to the toll gate information acquisition unit of the vehicle-mounted device unit
Then, the toll gate information acquisition unit receives the toll gate information.
And sends an interrupt signal to the ETC processing unit,
The ETC processing unit that has received the interrupt signal is
If the loading unit is in sleep mode,
To the operation mode, and
Reception of the carrier frequency information from the gate system section
In preparation for transmission, information reception at the carrier frequency information acquisition unit
The car navigation system.
The communication section of the specific driving lane such as the toll booth
Specifies the carrier frequency of the carrier and outputs the carrier frequency information
Then, the carrier frequency information is transferred to the in-vehicle device section.
The transmission frequency information acquisition unit acquires the
Notify the memory access block to transfer the control processing unit.
Start the transmission frequency setting process, and
Is the carrier frequency of the notified A mode or B mode.
Select the wave number from the frequency data in the memory
Set the frequency setting block in the frequency setting block
The transmitter / receiver / converter to set the carrier frequency.
Set to the local oscillator of the demodulator and set to the local oscillator.
The determined carrier frequency is the transmission / reception unit / modulation / demodulation unit.
As the local oscillation frequency signal to the transmitter and the receiver of
And the transmitter and the receiver are connected to the roadside radio.
The vehicle-mounted device for an ETC system according to any one of claims 3 and 4, which is operable in synchronization with a carrier frequency of the device. 6. A roadside arranged at a plurality of points on a road network
What is claimed in claim 1 to claim 5 mounted on a vehicle and a wireless device.
The vehicle-mounted device for the ETC system according to item 1 and the roadside
Consists of a management center that collects information from wireless devices
And when the vehicle travels on the road network,
The traveling position and traveling locus of the vehicle on the road network,
Characterized by displaying on the display device of the management center
The vehicle running locus management system.