JP4517391B2 - In-vehicle device - Google Patents

Description

  The present invention relates to an ETC in-vehicle apparatus.

In recent years, on toll roads, there are an increasing number of toll booths that can use an automatic toll collection system (hereinafter also referred to as “ETC system”; ETC: Electronic Toll Collection). As shown in FIG. 1A and FIG. 1B, by performing wireless communication between the toll booth and the ETC in-vehicle device 1 mounted on the vehicle 2, the toll is automatically set without stopping the vehicle 2. It is a system that can be received (for example, Patent Document 1 below). The toll booth is provided with an antenna 3 for transmitting and receiving radio signals and a charge receiving device connected thereto. The ETC in-vehicle device 1 of the vehicle 2 is connected to an ETC card (not shown) for fee settlement, and the fee receiving device recognizes the information of this ETC card by wireless communication and then passes it to the card company. Make a charge.
JP 2001-283269 A

  By the way, the speed limit when the vehicle 2 enters the toll gate is about 20 km / h. However, at present, many vehicles pass at a speed significantly exceeding the speed limit, which is a big safety issue. Therefore, when the vehicle speed when passing through the toll gate exceeds the specified speed, it is considered that the driver is warned by voice or the like to keep the speed limit. However, if the driver is warned that the speed is exceeded while passing through the toll gate, the driver may suddenly brake, and as a result, the following vehicle may collide.

  The present invention has been made in the background as described above. In particular, when the vehicle speed exceeds a predetermined speed when the vehicle passes through the toll gate, the driver has safely exceeded the speed. It is an object of the present invention to provide an ETC in-vehicle device that can warn of this.

Means for Solving the Problems and Effects of the Invention

Car mounting device according to claim 1 to solve the above problems,
Equipped with a payment means mounted on the vehicle and paying the toll according to an automatic toll collection system that automatically pays the toll using wireless communication when the vehicle passes through the toll gate on the toll road ,
The toll gate that is closest to the direction of travel for the vehicles traveling on the road between the toll gates on the toll road is the next toll gate, and the closest toll gate that is opposite to the direction of travel is the previous toll gate.
Vehicle speed detecting means for detecting a vehicle speed when the vehicle passes the previous toll gate;
Vehicle speed determining means for determining whether the vehicle speed detected by the vehicle speed detecting means is faster than a predetermined speed;
Operation when the vehicle speed by the vehicle speed determining means determines faster than a predetermined speed, after passing through the toll booth of the previous, the warning that the there is excess speed at the previous tollgate passage at a predetermined timing Warning means to warn the person,
Equipped with a,
The warning means is
First sub-warning means for executing the warning at a timing after a predetermined time has passed since passing through the previous toll gate, or
A second sub warning means for executing the warning at a timing approaching a position away from the next toll gate by a predetermined distance;
The main feature is that

  According to the above-described ETC in-vehicle apparatus of the present invention, when the vehicle speed when passing the toll gate exceeds a predetermined speed, after passing the toll gate, there is an overspeed for the driver at a predetermined timing. Warn you. As a result, no warning is issued while passing through the toll booth, and the risk of sudden braking is reduced.

According to the first aspect of the present invention, the driver is warned that the speed has been exceeded after a predetermined time has elapsed since passing the toll gate. The warning can be, for example, a warning due to sound output from a speaker or the like. If a warning is given, for example, several seconds to several tens of seconds after passing through the toll gate, the driver will not step on the brake suddenly, and the risk of a rear-end collision accident of the following vehicle is reduced. In addition, this warning can alert the driver to reduce the speed when passing the next toll gate.

  The vehicle speed detection means may be a vehicle speedometer, for example. Information on the vehicle speed detected by the speedometer is sent to the ETC in-vehicle device. The above warning is given when the vehicle speed exceeds a certain speed.

The car mounting device according to claim 1, the vehicle speed when passing through the tollgate exceeds a predetermined speed, when approaching the next tollgate, warning that there is excess speed at the previous tollgate pass. Here, the time when the next toll gate approaches, for example, can be several tens to several hundred meters before the toll gate. If a warning is received at such a distance from the toll booth, the driver can gradually reduce the speed and pass through the toll booth at a safe speed.

Also, the car mounting device according to claim 2, in the vehicle mounting device according to claim 1, the vehicle is obtained by describing specific method for sensing that it has approached to the next tollgate,
Receiving an approach warning radio wave transmitted from the toll gate, and comprising an approach sensing means for sensing the approach of the vehicle to the toll gate,
The second sub- warning means warns the driver that there was an overspeed at the time of passing the previous toll gate when the approach sensing means sensed the approach to the next toll gate. is there.

Also, the car mounting device according to claim 3, in the vehicle mounting device according to claim 1, the vehicle is obtained by describing specific method for sensing that it has approached to the next tollgate,
A vehicle navigation device for displaying the current position of the vehicle on an electronic map and guiding the vehicle;
When the second sub- warning means determines that the vehicle has approached the next toll gate based on the position information from the vehicle navigation device, the second sub- warning means confirms that there was an overspeed at the previous passage through the toll gate. A warning is given to the driver.

Furthermore the invention of claim 4 is the vehicle mounting device according to claim 1,
Storage means for storing that there was an excess of speed when the vehicle speed determining means determines that the vehicle speed is faster than a predetermined speed;
A power switch for switching between connection and disconnection to the power source,
When the power switch is switched from a disconnected state to a connected state, the warning means has an overspeed at the previous passage through the toll booth when the storage means stores the overspeed. Warning to the driver.

More specifically, the storage means of the fourth aspect is a writable nonvolatile memory. That is, information is not lost even when the power is turned off. Thus, when the ETC in-vehicle device is turned on, it is possible to warn the driver that there was an excess of speed when passing through the previous toll gate.

Also, the car mounting device according to claim 5, in the vehicle mounting device according to claim 1,
Storage means for storing that there was an excess of speed when the vehicle speed determining means determines that the vehicle speed is faster than a predetermined speed;
Further comprising an interface portion for connecting the card to pay for the tolls through the card company,
The warning means, when the pre-listen over de connected to the interface unit, if it had the excess speed has been stored in the storage means, there is excess speed at the previous tollgate pass Warning to the driver.

According to the fifth aspect of the present invention, when the ETC card is connected to the interface unit, it is warned that the speed has been exceeded at the previous pass through the toll gate. Usually, since the ETC card is often inserted before using the toll road, the driver can receive a warning before using the toll road, and can drive safely.

Also, the car mounting device according to claim 6, in the vehicle mounting apparatus according to any one of claims 1 to 5,
An in-vehicle antenna that receives a radio signal transmitted from the toll gate for collection of tolls;
The effective reception distance from the reception start point at which the radio signal can be received as the vehicle approaches the toll gate to the reception end point at which the radio signal cannot be received through the toll gate in advance. Stored distance storage means;
Time measuring means for measuring the time that the vehicle passes from the reception start point to the reception end point by measuring the reception time of the radio signal received by the vehicle-mounted antenna;
The vehicle speed detecting means calculates the vehicle speed based on the reception time of the radio signal measured by the time measuring means and the effective reception distance.

According to the sixth aspect of the present invention, the vehicle speed can be calculated by measuring the time during which the in-vehicle antenna receives a radio signal and dividing the effective reception distance by the measurement time. Since the measurement of the reception time can be processed in the ETC in-vehicle device, other vehicle speed detection means such as a speedometer is not required, and the vehicle speed can be detected by the ETC in-vehicle device alone.

Further car mounting device according to claim 7, in the vehicle mounting apparatus according to any one of claims 1 to 5,
An in-vehicle antenna that receives a radio signal transmitted from the toll gate for collection of tolls;
Frequency measuring means for measuring the frequency of the radio signal received by the vehicle-mounted antenna;
Frequency storage means for storing in advance a stationary frequency when the wireless signal is received while the vehicle is stationary;
The vehicle speed detecting means further includes a frequency change amount due to a Doppler effect from a difference between the frequency measured by the frequency measuring means and the stationary frequency, or from a relative difference between a frequency immediately after the start of communication and a frequency immediately before the end of communication. And the speed of the vehicle is calculated based on the frequency change amount.

According to the seventh aspect of the invention, the vehicle speed can be detected by the ETC in-vehicle device alone by measuring the frequency of the radio signal shifted to the short wavelength side by the Doppler effect.

Also, the car mounting device according to claim 8, in the vehicle mounting device according to any one of claims 1 to 5,
It further comprises an in-vehicle GPS that detects the current position of the vehicle,
The vehicle speed detection means calculates the vehicle speed from a temporal change in the vehicle position detected by the in-vehicle GPS.

The invention of claim 9 is the vehicle mounting device according to claim 8,
An acceleration sensor for measuring the acceleration of the vehicle;
The vehicle speed detection means calculates the average speed of the vehicle by temporal change of the vehicle position detected by the in-vehicle GPS, and corrects the average speed using the acceleration measured by the acceleration sensor, The instantaneous speed when passing through the toll gate is calculated.

According to the eighth and ninth aspects of the invention, the vehicle speed can be detected by using the vehicle current position information measured by the vehicle-mounted GPS. Further, by correcting the vehicle speed using the acceleration detected by the acceleration sensor, the instantaneous speed when passing through the toll gate can be calculated.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
First, FIG. 2A shows an example of a block diagram. The ETC in-vehicle device 1 includes an in-vehicle antenna 4, a transmission / reception means 5, a control circuit 6, an operation means 7 for a user to input a command, an ETC card 11 for charge settlement, an interface unit 8 for connecting it, a liquid crystal, etc. A vehicle speed detecting means 12 such as a display means 9, a speaker 10 and a speedometer is provided.

  The entire operation is performed as follows. For example, when the vehicle 2 passes through the toll gate, the ETC on-vehicle device 1 receives the toll gate name and toll collection information that passes from the toll gate antenna 3 through the in-vehicle antenna 4. The control circuit 6 discriminates the toll gate name and toll collection information and displays them on the display unit 9 or outputs the sound from the speaker 10. The driver sees the screen of the display unit 9 or listens to the voice from the speaker 10 to confirm that the vehicle has passed the target toll gate and that the toll collection process has been performed. Further, when the charge collection information being received is identified, the control unit 6 reads information necessary for charge settlement from the ETC card 11 and wirelessly transmits the information from the in-vehicle antenna 4 to the antenna 3 of the passing toll gate. After the toll gate recognizes this information, it charges the card company for a passing fee.

  The control circuit 6 is configured as a computer including a CPU 61, a ROM 62, and a RAM 63. Information on the vehicle speed detected by the vehicle speed detection means is sent to the control circuit 6. The ROM 62 stores a program for determining whether the vehicle speed when the vehicle 2 passes the toll gate exceeds a predetermined speed, and a program for giving a warning at a predetermined timing after passing the toll gate. By reading and executing these programs, the control circuit 6 functions as warning means and vehicle speed determination means of the present invention. When the vehicle 2 passes the toll gate, the toll gate name and toll collection information are sent from the antenna 3 by radio signals. If the control circuit (vehicle speed determining means) 6 determines that the vehicle speed transmitted from the vehicle speed detecting means is faster than the predetermined speed when the in-vehicle antenna 4 receives this wireless signal, a predetermined time elapses as will be described later. After that, the fact that the speed has been exceeded is displayed on the display means 9, or the sound is output from the speaker 10.

  More specifically, the transmission / reception means 5 includes a detection diode D, a modulation circuit 51, a demodulation circuit 52, and a detection circuit 53, as shown in FIG. The detection diode D detects the received signal when the in-vehicle antenna 4 receives a radio signal transmitted from the antenna 3 at the toll gate. The demodulation circuit 52 is a circuit that demodulates the detected received signal to obtain the original fee collection information and outputs the received data to the control circuit 6 as received data. The modulation circuit 53 modulates the information output from the control circuit 6 into a transmission signal and causes the vehicle-mounted antenna 4 to output it. The detection circuit 53 is a circuit that detects the level of the detected reception signal. The control circuit 6 processes the post-demodulation information output from the demodulation circuit 52 when a detection signal of a certain level or more is input from the detection circuit 53. Thereby, for example, as shown in FIG. 1, when the antennas 3 are adjacent to each other, erroneous communication can be prevented and the fee collection process can be performed reliably.

  Next, the operation of the ETC in-vehicle apparatus of the present invention will be described using the flowchart of FIG. First, when the vehicle approaches the toll booth and receives a radio signal from the toll booth (step S1), as described above, wireless communication is performed with the toll booth side to perform a process of paying the toll (step S2). ). Thereafter, the vehicle speed detecting means 12 detects the vehicle speed when passing through the toll gate (step S3). Then, the control circuit (vehicle speed determining means) 6 determines whether or not the detected vehicle speed is faster than a predetermined speed (step S4). When the vehicle speed exceeds a predetermined speed, a warning is not issued immediately, but a warning is given at a predetermined timing after passing through the toll gate. Specifically, after determining whether or not a predetermined time has passed (for example, about several seconds to several tens of seconds) in step S5, the process proceeds to step S6, and the control circuit (warning means) 6 issues a warning signal and displays on the display means 9. Or audio output from the speaker 10. As a result, the driver is warned that the speed has been exceeded after some time has passed since the toll booth, and therefore, the driver is not required to step on the brakes in the toll booth and is safe. This warning will also help you to reduce the speed at the next toll booth.

  According to the present invention, when the vehicle 2 passes the toll gate and exceeds the speed, it is possible to warn at the timing when the vehicle 2 approaches the next toll gate. In order to sense the approach to the next toll gate, for example, as shown in FIG. 5, a vehicle navigation device 16 is used. The vehicle navigation device 16 detects the current position by GPS (Global Positioning System) or the like as the vehicle travels, displays the current position together with the road map on the display device, and starts from the current position. An appropriate route to the ground is set and guided by a display device, an audio output device, or the like. On the other hand, as shown in FIG. 5, a storage means 13 (a rewritable nonvolatile memory or HDD is used) is mounted. This storage means 13 stores that there was an excess of speed when the previous charge passed.

  The operation of the ETC in-vehicle device using the vehicle navigation device will be described with reference to the flowchart of FIG. First, it is determined whether or not the vehicle 2 has approached the toll gate based on the current position information from the vehicle navigation device (step S7), and then it is determined whether or not there has been an excessive speed at the previous passage through the toll gate (step S8). In step 7, for example, it is determined based on whether the vehicle approaches from several tens of meters to several hundred meters before the toll gate. In step S9, the CPU 61 accesses the storage means 13 when approaching the toll gate, and determines whether or not there has been an excessive speed at the previous passage through the toll gate. As a result, if the speed has been exceeded at the previous passage through the toll gate, the control circuit 6 issues a warning by displaying an image from the display device 9 or outputting a sound from the speaker 10 (step S9). Thereafter, when a radio signal is received from the toll booth as the vehicle travels (step S10), a process for paying the toll by performing radio communication with the toll booth is performed (step S11). Then, the vehicle speed detection means detects the vehicle speed (step S12), and determines whether the control circuit (vehicle speed determination means) 6 is faster than a predetermined speed (step S13). As a result, when it is determined that the vehicle speed is higher than the predetermined speed, the storage means 13 stores that the speed has been exceeded.

  In the flowchart of FIG. 4 above, it is important not to warn when the vehicle passes the toll gate, but to warn before that. With this warning, the driver can gradually reduce the speed as he approaches the toll gate, and can pass through the toll gate at a safe speed. If the vehicle current position information from the vehicle navigation device is not used and a warning is issued at the timing when the in-vehicle antenna 4 receives a radio signal from the toll booth, the driver may suddenly brake and a rear-end collision may occur. There is a risk of occurrence.

  In addition, as shown in FIG. 6A, the present invention can warn that there was an overspeed when the ETC in-vehicle apparatus was turned on when it passed the previous toll gate. That is, after the power switch is turned on in step 15, the control circuit 6 accesses the storage means 13 and warns the driver when it is stored that there was an overspeed at the previous passage through the toll gate. To do. Normally, when the vehicle engine is started, the ETC in-vehicle device is turned on at the same time, so the driver can be alerted at the same time as the engine is started, and be careful not to overspeed when passing the next toll gate. be able to.

  Further, as shown in FIG. 6B, when the ETC card 11 is connected to the interface unit 8 (step S15 ′), a warning may be given that there was an overspeed when the previous toll gate passed. (Steps S16 and S17). In this way, since the driver can receive a warning when the ETC card 11 is inserted into the interface unit 8 in order to use the toll road, attention can be paid when passing the next toll gate.

  According to the present invention, vehicle speed information from a speedometer or the like is not required, and the vehicle speed detection means 12 can be incorporated in the control circuit 6. That is, a program for calculating the vehicle speed is stored in the ROM 62, and when the CPU 61 executes the program, the control circuit 6 functions as a vehicle speed detecting means. Hereinafter, a specific method for calculating the vehicle speed will be described.

  First, as shown in FIG. 7, an antenna 3 is installed at a toll booth, from which a radio signal for toll collection is transmitted. When the vehicle 2 approaches the toll gate, the vehicle 2 starts to enter an area where radio signals can be received. As described above, the detection circuit 53 is incorporated in the transmission / reception device 5, and the control circuit 6 performs information processing only when a detection signal having a certain intensity or more is output. That is, reception is considered only when the electric field strength of the radio signal that can be received on the vehicle 2 side becomes a certain level or more.

  The distance (effective reception distance) from a point at which a radio signal can be received (reception start point) to a point at which reception becomes impossible (reception end point) does not vary greatly depending on the toll gate, and takes a substantially constant value. This effective reception distance is stored in advance in the ROM 62 or the storage means 13 of the ETC in-vehicle device. On the other hand, the ETC in-vehicle device is provided with means (time measuring means) for measuring the time (reception time) during which the in-vehicle antenna 4 can receive a radio signal. This makes it possible to measure the time for the vehicle 2 to pass from the reception start point to the reception end point.

  FIG. 8A and FIG. 8B show the relationship between the change in electric field strength and time when the vehicle 2 passes at high speed and low speed. It can be seen that the electric field strength increases when approaching the antenna 3, and the electric field strength decreases rapidly as the distance from the antenna 3 increases. Here, the electric field intensity at which the detection circuit can detect a radio signal and output a detection signal of a predetermined level is defined as a specified electric field intensity, and a time for receiving an electric field intensity equal to or higher than the specified electric field intensity is defined as a reception time. The speed of the vehicle 2 and the reception time are in an inversely proportional relationship. That is, when the vehicle passes at a high speed, the reception time of the radio signal is short, and when the vehicle passes at a low speed, the reception time is long. By utilizing this relationship, the vehicle speed can be detected by the ETC in-vehicle device alone. That is, the vehicle speed can be calculated by measuring the time when the in-vehicle antenna 4 receives the radio signal using the above-mentioned time measuring means and dividing the effective reception distance stored in the ROM 62 by the measurement time.

  On the other hand, it is also possible to calculate the vehicle speed by measuring the frequency change amount of the radio signal due to the Doppler effect. That is, a means (frequency measuring means) for measuring the frequency of the radio signal received by the vehicle-mounted antenna 4 is provided. The frequency when the radio signal is measured in a state where the vehicle 2 is stationary is set as the stationary frequency, and the stationary frequency is stored in advance in the ROM 62 or the storage unit 13 of the ETC in-vehicle device. Since the frequency of the radio signal measured by the frequency measuring means is shifted to the high frequency side due to the Doppler effect, the vehicle speed is calculated using the difference. Alternatively, the vehicle speed is calculated from the relative difference between the frequency immediately after the start of communication and the frequency immediately before the end of communication.

  Further, as shown in the block diagram of FIG. 9, the vehicle speed can be calculated by using the in-vehicle GPS 14. The in-vehicle GPS 14 receives a radio wave from a satellite and detects the current position of the vehicle, and is used as a basic component of the above-described in-vehicle navigation device 16. The vehicle speed can be calculated from the temporal change of the current position of the vehicle 2 detected by the in-vehicle GPS 14.

  On the other hand, as shown in the block diagram of FIG. 9, the acceleration sensor 15 may be used in combination. Although the acceleration sensor 15 is a sensor that measures the acceleration of the vehicle 2, there is a problem that an offset error is likely to occur. Therefore, when the vehicle passes the toll gate by calculating the average speed from the temporal change of the current position of the vehicle 2 detected by the in-vehicle GPS 14 and correcting the average speed using the acceleration detected by the acceleration sensor 15. It is possible to accurately calculate the instantaneous speed of.

Explanatory drawing of an ETC system. An example of a block diagram of an ETC in-vehicle device. An example of a flowchart. The block diagram of the ETC vehicle-mounted apparatus carrying the memory | storage means 13 and the vehicle navigation apparatus 16. FIG. Another flowchart. FIG. 6 is a flowchart different from FIG. 3 and FIG. 5. Explanatory drawing of an effective receiving distance. The graph showing the electric field intensity of the radio signal which vehicles receive, and the relation of time. The block diagram of the ETC vehicle-mounted apparatus containing vehicle-mounted GPS and an acceleration sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ETC vehicle-mounted apparatus 2 Vehicle 3 Antenna 4 Car-mounted antenna 5 Transmission / reception means 6 Control circuit (warning means, vehicle speed detection means)
7 Operation means 8 Interface section 9 Display means 10 Speaker 11 ETC card 12 Vehicle speed detection means 13 Storage means 14 Car-mounted GPS
15 Acceleration sensor 16 Vehicle navigation device

Claims (9)

Equipped with a payment means mounted on the vehicle and paying the toll according to an automatic toll collection system that automatically pays the toll using wireless communication when the vehicle passes through the toll gate on the toll road ,
The toll gate that is closest to the direction of travel for the vehicles traveling on the road between the toll gates on the toll road is the next toll gate, and the closest toll gate that is opposite to the direction of travel is the previous toll gate.
Vehicle speed detecting means for detecting a vehicle speed when the vehicle passes the previous toll gate;
Vehicle speed determining means for determining whether the vehicle speed detected by the vehicle speed detecting means is faster than a predetermined speed;
Operation when the vehicle speed by the vehicle speed determining means determines faster than a predetermined speed, after passing through the toll booth of the previous, the warning that the there is excess speed at the previous tollgate passage at a predetermined timing Warning means to warn the person,
Equipped with a,
The warning means is
First sub-warning means for executing the warning at a timing after a predetermined time has passed since passing through the previous toll gate, or
A second sub warning means for executing the warning at a timing approaching a position away from the next toll gate by a predetermined distance;
Car mounting device you comprising the. Receiving an approach warning radio wave transmitted from the toll gate, and comprising an approach sensing means for sensing the approach of the vehicle to the toll gate,
The second sub-warning means warns the driver that there was an overspeed at the time of passing the previous toll gate when the approach sensing means sensed the approach to the next toll gate. car mounting device of a claim 1, wherein. A vehicle navigation device for displaying the current position of the vehicle on an electronic map and guiding the vehicle;
When the second sub-warning means determines that the vehicle has approached the next toll gate based on the position information from the vehicle navigation device, the second sub-warning means confirms that there was an overspeed at the previous passage through the toll gate. car mounting device according to claim 1, wherein is for warning to the driver. Storage means for storing that there was an excess of speed when the vehicle speed determining means determines that the vehicle speed is faster than a predetermined speed;
A power switch for switching between connection and disconnection to the power source,
When the power switch is switched from a disconnected state to a connected state, the warning means has an overspeed at the previous passage through the toll booth when the storage means stores the overspeed. car mounting apparatus according to claim 1, wherein the warning to the driver that. Storage means for storing that there was an excess of speed when the vehicle speed determining means determines that the vehicle speed is faster than a predetermined speed;
An interface unit for connecting a card for paying the toll through a card company;
When the warning means is stored in the storage means that the speed has been exceeded when the card is connected to the interface unit, the warning means that the speed has been exceeded at the previous pass through the toll booth. car mounting apparatus according to claim 1, wherein the warning to the user. An in-vehicle antenna that receives a radio signal transmitted from the toll gate for collection of tolls;
The effective reception distance from the reception start point at which the radio signal can be received as the vehicle approaches the toll gate to the reception end point at which the radio signal cannot be received through the toll gate in advance. Stored distance storage means;
Time measuring means for measuring the time that the vehicle passes from the reception start point to the reception end point by measuring the reception time of the radio signal received by the vehicle-mounted antenna;
Further comprising a vehicle speed detecting means, a receiving time of the radio signal which the timing means is measured, the effective receiving distance based and calculates the vehicle speed to any one of claims 1 to 5 car mounting device as claimed. An in-vehicle antenna that receives a radio signal transmitted from the toll gate for collection of tolls;
Frequency measuring means for measuring the frequency of the radio signal received by the vehicle-mounted antenna;
Frequency storage means for storing in advance a stationary frequency when the wireless signal is received while the vehicle is stationary;
The vehicle speed detection means calculates a frequency change amount due to the Doppler effect from a difference between the frequency measured by the frequency measurement means and the stationary frequency, and calculates the speed of the vehicle based on the frequency change amount. or, a frequency immediately after the start of communication, the car mounting device according to any one of claims 1 to 5 and calculates the relative difference in the frequency of communication just before the end. It further comprises an in-vehicle GPS that detects the current position of the vehicle,
The vehicle speed detecting means, the car mounting device according to any one of the vehicle according to claim 1 to 5 from a temporal variation of the vehicle position is to calculate the vehicle speed detected by the GPS. An acceleration sensor for measuring the acceleration of the vehicle;
The vehicle speed detection means calculates the average speed of the vehicle by temporal change of the vehicle position detected by the in-vehicle GPS, and corrects the average speed using the acceleration measured by the acceleration sensor, car mounting device of claim 8, and calculates the instantaneous speed when passing through the toll booth.

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