JP4412044B2 - OBE - Google Patents

Description

  The present invention relates to an in-vehicle device that is provided in a vehicle and performs DSRC communication with a roadside device installed on a roadside.

Conventionally, as a system for performing this DSRC communication, for example, there is an ETC system (ETC is a registered trademark) and an electronic license plate system.

The on-vehicle device of such a system employs an active method that consumes a relatively large amount of current. For this reason, there exists what reduced current consumption by the intermittent reception operation which performs reception intermittently (for example, refer to patent documents 1 to 3).
JP-A-10-336760 JP-A-10-210563 JP-A-9-27782

  By the way, in addition to the ETC system and the electronic license plate system described above, many systems using this DSRC communication have been studied. Depending on the service, for example, even in a stopped vehicle with the engine stopped, the vehicle-mounted device and the roadside Some devices require communication with the machine.

  However, since many on-vehicle devices that perform DSRC communication are configured to be supplied with power from a battery mounted on a vehicle via an accessory switch, power supply from the battery is stopped when the accessory switch is turned off. As a result, the signal transmitted from the roadside device cannot be received.

  Therefore, if power is supplied directly from the battery of the vehicle, power can be supplied regardless of the state of the accessory switch. However, since the vehicle-mounted device operates with the engine stopped, the current consumption of the vehicle-mounted device A large battery may cause the battery to run out.

  Moreover, if the battery is built in the vehicle-mounted device and the power is supplied from this battery, the problem of the battery going up is eliminated, but for example, the vehicle-mounted device operates even when the vehicle is stopped. If the current consumption of the vehicle-mounted device is large, the battery life will be shortened.

  In any case, such a vehicle-mounted device is required to operate with low current consumption even when the engine is stopped.

  By the way, in the DSRC communication, the vehicle-mounted device starts communication by sending a polling signal from the roadside device. Therefore, it is necessary for such a vehicle-mounted device to be able to receive a polling signal from a roadside device with low current consumption even when the vehicle is stopped.

  Thus, if a polling signal is periodically received from the roadside device by performing an intermittent reception operation, it is possible to reduce current consumption. However, when the intermittent reception operation is simply performed at a constant intermittent period, the following problem occurs.

  When the intermittent cycle is long, the current consumption is reduced, but it is conceivable that the vehicle passes through the communication area without receiving a signal from the roadside device during traveling and misses the signal from the roadside device.

  On the contrary, when the intermittent cycle is short, it is possible to prevent the signal from the roadside device from being missed. However, since the polling signal is received with a short intermittent cycle even when the vehicle is stopped, the current consumption increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent signals from being missed from a roadside machine while traveling and to receive a signal from a roadside machine with low current consumption even when the vehicle is stopped.

In order to achieve the above object, according to the first aspect of the present invention, there is provided an in-vehicle device that is provided in a vehicle and performs DSRC communication with a roadside device installed on the roadside, and receiving means that receives a signal from the roadside device; The control means comprises: a control means for causing the receiving means to receive a signal from the roadside device intermittently at a predetermined timing; and a vehicle state determination means for judging whether the vehicle is running or stopped. When the vehicle state determining means determines that the vehicle is running, the receiving means is intermittently operated every first intermittent period, and when the vehicle state determining means determines that the vehicle is stopped, When the receiving means is intermittently operated every second intermittent period longer than one intermittent period and information for specifying the moving state of the vehicle is transmitted to the roadside machine in response to the start of DSRC communication with the roadside machine, the roadside The machine moves the vehicle The information indicating the set value of the intermittent period of the receiving means adapted to the moving state of the vehicle is returned based on the information for specifying the state, and the control means returns the information of the receiving means returned from the roadside machine. The reception means is intermittently operated at an intermittent period according to information indicating the set value of the intermittent period .

As described above, when the vehicle state determination unit determines that the vehicle is running, the control unit intermittently operates the reception unit for each first intermittent period, and the vehicle state determination unit is stopping the vehicle. Since the receiving means is intermittently operated every second intermittent period longer than the first intermittent period, it is possible to prevent the signal from being removed from the roadside machine while traveling, and even when the vehicle is stopped A signal from the roadside device can be received with low current consumption. Further, the control means can cause the reception means to intermittently operate at an intermittent period according to information indicating the set value of the intermittent period of the reception means returned from the roadside device.
Further, as in the invention described in claim 2, the control means can set the second intermittent period in a range in which the vehicle does not pass without receiving a signal from the roadside machine.
Further, as in the invention described in claim 3, the roadside machine changes the set value of the intermittent period of the receiving means according to the contents of the service provided by the roadside machine, and the control means The receiving means can be intermittently operated according to the information indicating the setting value of the intermittent period of the receiving means changed according to the contents of the service.

According to a fourth aspect of the present invention, the vehicle state determination means includes a vibration sensor that detects vibration during traveling of the vehicle, and the vehicle is traveling based on the vibration detected by the vibration sensor. Therefore, it is possible to eliminate the need for a cable for inputting a signal for determining whether the vehicle is traveling or stopped.

According to a fifth aspect of the present invention, the vehicle state determination means has an inclination sensor that detects an inclination angle that changes as the vehicle travels, and is detected by the vibration detected by the vibration sensor and the inclination sensor. Whether the vehicle is running or stopped can be determined based on the tilt angle.

The invention according to claim 6 comprises processing means for performing signal processing of the signal received by the receiving means, and transmitting means for transmitting the signal from the processing means to the roadside device, and the control means comprises the receiving means. The processing means and the transmission means are activated and stopped separately.

  As described above, the control unit starts and stops the reception unit, the processing unit, and the transmission unit separately, so that the current consumption of the vehicle-mounted device can be reduced.

  In the invention according to claim 6, since the battery for supplying power is provided, and the receiving means and the control unit are supplied with power from the battery, the power is supplied to the receiving means and the control unit regardless of the state of the accessory switch. Can be supplied.

  FIG. 1 shows a block configuration of the vehicle-mounted device according to the embodiment of the present invention. The vehicle-mounted device 1 includes a reception circuit 11, a transmission circuit 12, a DSRC processing unit 13, a memory 14, a vibration sensor 15, a power supply control unit 17, a timer 18, and a power supply 19.

  In the configuration in which power is supplied from the vehicle battery via the accessory switch, since the power supply is stopped when the accessory switch is turned off, the vehicle-mounted device 1 in this embodiment is not supplied from the vehicle battery, It operates by power feeding from a power source 19 built in the vehicle-mounted device 1.

  The receiving circuit 11 receives a radio wave transmitted from the DSRC roadside device, performs processing such as amplification and demodulation on the received signal, and outputs a signal of the processing result to the DCRC processing unit 13.

  The transmission circuit 12 performs processing such as modulation and amplification on the signal output from the DSRC processing unit 13, and transmits the resultant signal as a radio wave to the DSRC roadside device.

  The DSRC processing unit 13 is configured as a normal computer, executes various arithmetic processes according to a program stored in the memory 14, and exchanges signals with the receiving circuit 11, the transmitting circuit 12, the memory 14, the power control unit 17, and the like. . The processing of the DSRC processing unit 13 includes analysis of a signal received by the reception circuit 11 and generation of a signal to be transmitted to the DSRC roadside device via the transmission circuit 12.

  The memory 14 includes a ROM in which a program for operating the computer of the DSRC processing unit 13 is stored, a RAM in which data is temporarily stored, a flash memory as a nonvolatile memory, and the like.

  The vibration sensor 15 is built in the vehicle-mounted device, detects vibration generated when the vehicle is traveling and vibration generated when the engine is operated, and outputs the detected vibration to the power supply control unit 17.

  The tilt sensor 16 is built in the vehicle-mounted device, detects a tilt angle that changes as the vehicle travels, and outputs the detected tilt angle to the power supply control unit 17.

  The power control unit 17 is configured as a normal computer, and includes a nonvolatile memory such as a CPU, a ROM, a RAM, and a flash memory. The CPU of the power supply control unit 17 reads the program stored in the ROM and executes various processes, and starts and stops each block of the reception circuit 11, the transmission circuit 12, the DSRC processing unit, and the memory 14 by an on / off control signal. Control.

  The timer 18 measures time, compares the measured time with a preset comparison value, and outputs a predetermined signal when the measurement time reaches the comparison value.

  The power source 19 is specifically constituted by a battery, and supplies power to each block of the on-vehicle device 1 described above.

  In the configuration described above, the power supply control unit 17 determines whether the vehicle is running or stopped based on the vibration detected by the vibration sensor 15 and the inclination angle detected by the inclination sensor 16 as follows. .

  The vibration frequency f generated by the rotation of the engine increases as the engine speed increases, as shown in FIG. Further, the vibration frequency f0 shown in FIG. 2 is set to a frequency slightly higher than the vibration frequency generated by idling.

  Since the engine speed when the vehicle travels is greater than the engine speed during idling, the power supply control unit 17 determines whether the vibration frequency f is equal to or higher than the frequency f0 slightly higher than the vibration frequency generated by idling. It can be determined whether the vehicle is traveling or stopped.

  Specifically, the power supply control unit 17 extracts the vibration frequency f generated by the rotation of the engine from the vibration detected by the vibration sensor 15, and when the vibration frequency f is equal to or higher than a predetermined vibration frequency f0, the vehicle is running. If the vibration frequency f is less than the predetermined vibration frequency f0, it can be determined that the vehicle is stopped.

  Further, when the vehicle accelerates, the rear part of the vehicle is lowered as shown in FIG. 3A, and when the vehicle decelerates, the front part of the vehicle is lowered as shown in FIG. 3B. The tilt sensor 16 detects the tilt angle that changes as the vehicle travels, and outputs the detected tilt angle.

  In the present embodiment, it is determined whether the vehicle is running or stopped based on the vibration frequency f and the inclination angle detected by the inclination sensor 16.

  For example, when it is detected that the rear part of the vehicle has been lowered due to the inclination angle and the vibration frequency f is equal to or higher than a predetermined vibration frequency f0, it is determined that the vehicle is running.

  Further, when it is detected that the front portion of the vehicle has been lowered due to the inclination angle and the vibration frequency f is less than the predetermined vibration frequency f0, it is determined that the vehicle is stopped.

  Further, when the vibration frequency f is equal to or higher than the predetermined vibration frequency f0 and the inclination angle does not change for a predetermined time or more, it is determined that the vehicle is running. Such a case corresponds to, for example, a case where the vehicle travels on a highway for a long time at a constant speed.

  Further, when the vibration frequency f is less than the predetermined vibration frequency f0 and the inclination angle does not change for a predetermined time or more, it is determined that the vehicle is stopped. As shown in FIG. 4, since the vehicle does not necessarily stop at a flat place, the determination is based on the change in the inclination angle, not the magnitude of the inclination angle.

  As described above, the power supply control unit 17 determines whether the vehicle is stopped or traveling based on the signals output from the vibration sensor 15 and the tilt sensor 16.

  Next, the basic operation of the vehicle-mounted device 1 will be described with reference to FIG.

  First, when the vehicle is stopped and the vibration sensor 15 does not detect vibration generated when the vehicle travels or vibration generated when the engine is operated, the receiving circuit 11 is intermittently operated with a relatively long cycle under the control of the power supply control unit 17. An intermittent reception operation is performed every cycle T1. The receiving circuit 11 performs a receiving operation only during the ON period shown in the figure.

  Next, when the vehicle starts traveling and vibrations generated when the vehicle is traveling and vibrations generated when the engine is operated are detected by the vibration sensor 15, the receiving circuit 11 starts from the intermittent cycle T <b> 1 under the control of the power supply control unit 17. The intermittent reception operation is performed every intermittent cycle T2 having a short cycle.

  When the reception circuit 11 receives a reception signal from the roadside machine, the DSRC processing unit 13 is activated under the control of the power supply control unit 17.

  Next, when the transmission circuit 12 is activated under the control of the power supply control unit 17 and a transmission signal is transmitted from the transmission circuit 12, the transmission circuit 12 stops.

  As described above, the power supply control unit 17 starts and stops the reception circuit 11, the DSRC processing unit 13, and the transmission circuit 12 separately as necessary, thereby reducing current consumption.

  Next, referring to FIG. 6 and FIG. 7, when the vehicle equipped with the vehicle-mounted device 1 is stopped in the communication area of the roadside device and when the vehicle equipped with the vehicle-mounted device 1 moves through the communication area of the roadside device at high speed. The intermittent reception operation of the reception circuit 11 when passing will be described.

  FIG. 6 shows a situation in which the vehicle 2 equipped with the vehicle-mounted device is stopped in the communication area of the roadside device 4 and the vehicle 3 equipped with the vehicle-mounted device is traveling in the communication area of the roadside device 4 at a speed of 100 km / h. It is a figure.

  As shown in FIG. 7, when the vehicle 2 being stopped determines that the power control unit 17 of the vehicle-mounted device is stopped based on signals output from the vibration sensor 15 and the inclination sensor 16, the receiving circuit 11 is intermittently connected. The intermittent reception operation is performed at the period T1. As described above, when the receiving circuit 11 is intermittently operated every intermittent period T1 and a transmission signal (including a polling signal) transmitted from the roadside device is received during the ON period of the receiving circuit 11, communication is performed with the roadside device.

  When the vehicle 2 starts traveling, it is determined that the vehicle 2 is traveling based on signals output from the vibration sensor 15 and the tilt sensor 16, and the reception circuit 11 is intermittently received at an intermittent period T2 shorter than the intermittent period T1. Let As described above, the vehicle-mounted device 1 intermittently operates the receiving circuit 11 and receives the transmission signals a, b, c, d, e, and f from the roadside device.

  On the other hand, when the power controller of the vehicle-mounted device of the vehicle 3 traveling at a speed of 100 km / h determines that the vehicle is traveling based on signals output from the vibration sensor and the tilt sensor, the reception circuit 11 is intermittently received at the intermittent period T2. Make it work. As described above, when the reception circuit 11 is intermittently operated every intermittent period T2 and a transmission signal (including a polling signal) transmitted from the roadside device is received during the ON period of the reception circuit 11, communication is performed with the roadside device.

  The intermittent period T2 of the electric receiving circuit 11 during traveling is set to be sufficiently short so that the vehicle does not pass through the communication area without receiving a signal from the roadside machine.

  As shown in FIG. 7, since the intermittent cycle T1 of the power receiving circuit 11 when the vehicle is stopped is shorter than the intermittent cycle T2 of the power receiving circuit 11 during traveling, the power receiving circuit 11 is uniformly distributed at the intermittent cycle T2. The current consumption can be reduced as compared with the case of intermittent operation.

  Next, with reference to FIG. 8, the processing of the CPU of the power supply control unit 17 of the vehicle-mounted device 1 will be described. Hereinafter, the processing of the CPU of the power control unit 17 will be described as the processing of the power control unit 17.

  The power supply control unit 17 changes the intermittent period of the receiving circuit 11 by changing the comparison value of the timer 18 depending on whether the vehicle is running or stopped. Thus, the comparison value of the timer 18 can be set by communication. In the present embodiment, priority is given to setting by communication. When the comparison value of the timer 18 is set from the roadside machine, the comparison value of the timer 18 is stored in the nonvolatile memory of the power supply control unit 17.

  First, the power supply control unit 17 determines whether to give priority to the setting of the comparison value of the timer 18 in communication based on whether the comparison value of the timer 18 is stored from the roadside device in the nonvolatile memory (S100). .

  If it is determined that priority is not given to the timer setting in communication (NO in S100), it is determined whether the vehicle is stopped based on signals from the vibration sensor 15 and the tilt sensor 16 (S102).

  If it is determined that the vehicle is stopped, the comparison value of the timer 18 is set to the intermittent period T1 (S104), and the process proceeds to S108.

  If it is determined in S102 that the vehicle is traveling, the comparison value of the timer 18 is set to an intermittent cycle T2 that is shorter than the intermittent cycle T1 (S104), and the process proceeds to S108.

  In S108, based on the output signal from the timer 18, it is determined whether or not the measurement time measured by the timer 18 has reached a preset comparison value (intermittent period T1 or T2) (S108).

  If it is determined that the measurement time does not reach the preset comparison value (NO in S108), the process returns to S102, and the processes of S102 to S108 are repeated.

  If it is determined in S108 that the measurement time has reached a preset comparison value (YES in S108), the reception circuit 11 is activated (S110), and the reception circuit 11 is transmitted from the roadside device. Based on whether the signal is normally received or not, it is determined whether or not the normal signal is received (S112).

  If it is determined that a normal signal is not received (NO in S112), the power receiving circuit 11 is stopped (S114) and the process returns to S102.

  If it is determined in S112 that a normal signal has been received (YES in S112), the DSRC processing unit 13 is activated (S116).

  The DSRC processing unit 13 analyzes the signal received by the receiving circuit 11 and generates a signal to be transmitted to the DSRC roadside device via the transmitting circuit 12.

  Then, it is determined whether a signal to be transmitted from the DSRC processing unit 13 to the DSRC roadside device is generated (S118).

  If it is determined that a signal to be transmitted is not generated (NO in S118), the process returns to S102.

  If it is determined in S118 that a signal to be transmitted has been generated (YES in S118), the transmission circuit 12 is activated (S120), and a transmission / reception operation is performed (S122).

  Next, based on whether or not the receiving circuit 11 has received the comparison value of the timer 18 from the roadside machine, it is determined whether or not the timer 18 is set from the roadside machine (determined as YES in S124).

  If it is determined that the timer 18 is set from the roadside machine (YES in S124), the comparison value received from the roadside machine is set in the timer 18 (S126).

  If it is determined in S124 that the timer 18 is not set from the roadside device (NO in S124), the priority setting of the timer 18 in communication is canceled. Specifically, the setting of the comparison value of the timer 18 from the roadside device stored in the nonvolatile memory of the power supply control unit 17 is cleared (S128).

  Next, it is determined whether or not the communication has ended (S130). If the communication has not ended, the processes of S122 to S126 are repeated.

  In S110, when the comparison value of the timer 18 is stored in the nonvolatile memory from the roadside machine, it is determined that the setting of the comparison value of the timer 18 in communication is given priority (YES in S100), and the nonvolatile memory is determined. The comparison value stored in is set as the comparison value of the timer 18 and the process proceeds to S108.

  If it is determined in S130 that the communication is completed, all the circuits of the reception circuit 11, the transmission circuit 12, and the DSRC processing unit 13 are stopped (S132), and the process returns to the determination in S102.

  Next, with reference to FIG. 9, the sequence diagram between the roadside machine and the onboard equipment 1 in the case of setting the timer of the onboard equipment 1 from the roadside machine is shown. In DSRC communication, communication is started after the vehicle-mounted device 1 receives a polling signal from a roadside device. When receiving the polling signal from the roadside device, the vehicle-mounted device 1 starts communication with the roadside device, and transmits / receives data in the sequence shown in FIG. 9 according to the DSRC system standard (ARIB STD-T75). . The roadside device can set the timer of the vehicle-mounted device 1 according to the traveling state of the vehicle-mounted device 1 as described below.

  First, when an ID code for identifying a vehicle-mounted device is transmitted from the vehicle-mounted device 1 to the roadside device, a BST (Beacon Service Table) is transmitted from the roadside device to the vehicle-mounted device 1.

  The onboard equipment 1 will transmit VST (Vehicle Service Table) to a roadside machine, if this BST is received.

  Next, the roadside device transmits a data read request and a vehicle state request command to the vehicle-mounted device 1 to read the vehicle state from the vehicle-mounted device 1. The vehicle state includes information indicating the traveling state of the vehicle. Information indicating the traveling state of the vehicle is set to “1” when the vehicle is traveling and “0” when the vehicle is stopped.

  Next, the roadside device transmits the set value of the timer 18 corresponding to the vehicle state read from the vehicle-mounted device 1.

  And the onboard equipment 1 sets the timer 18 based on the setting value of the timer 18 transmitted from the roadside machine.

  As described above, the roadside device can set the timer of the vehicle-mounted device 1 according to the traveling state of the vehicle-mounted device 1.

  FIG. 10 is an explanatory diagram for calculating the current consumption. As shown in FIG. 10, it is assumed that the current consumption during the receiving circuit operation time (on time) is 10 mA, and the current consumption of the power receiving circuit 11 during the off time is 5 μA. Hereinafter, the on-time is set to 20 mSEC, the battery capacity is set to 2000 mAh, and the number of days that the power receiving circuit 11 can operate with this battery is calculated.

  First, when operated continuously, the number of days that the power receiving circuit 11 can operate with this battery is expressed by Equation 1.

(Equation 1)
2000 mAh ÷ 10 mA ÷ 24 h = 8.3 days Next, when the intermittent period of the power receiving circuit 11 is set to 50 mSEC, the number of days that the power receiving circuit 11 can operate with this battery is expressed by Formula 2.

(Equation 2)
2000 mAh ÷ ((10 mA × 20 mSEC / 50 mSEC) + (5 μA × 30 mSEC / 50 mSEC)) ÷ 24 h = 20.8 days Next, when the intermittent period of the electric receiving circuit 11 is operated as 1 SEC, the electric receiving circuit is operated by this battery. The number of days in which 11 can operate is expressed by Equation 3.

(Equation 3)
2000 mAh / ((10 mA × 20 mSEC / 1 SEC) + (5 μA × 980 mSEC / 1 SEC)) ÷ 24 h = 41.6 days In this way, the longer the intermittent cycle of the receiving circuit 11, the lower the current consumption of the electric receiving circuit 11. Battery life can be extended.

  As described above, the vehicle-mounted device 1 includes the receiving circuit 11 that receives the signal from the roadside device, and the power supply control circuit 17 that causes the receiving circuit 11 to receive the signal from the roadside device intermittently at a predetermined timing. When it is determined that the vehicle is traveling, the control circuit 17 causes the reception circuit 11 to intermittently operate at each first intermittent period. When it is determined that the vehicle is stopped, the control circuit 17 is longer than the first intermittent period. Since the receiving circuit 11 is intermittently operated every second intermittent period, it is possible to prevent signals from being removed from the roadside machine while traveling and to receive signals from the roadside machine with low current consumption even when the vehicle is stopped. Can do.

  Moreover, the battery life can be extended by reducing the current consumption in this way.

  Further, since the power supply control circuit 17 determines whether the vehicle is running or stopped based on the vibration detected by the vibration sensor 15, for example, a vehicle speed signal, a signal indicating the state of the ignition switch, etc. A cable for inputting a signal for determining whether the vehicle is running or stopped can be dispensed with.

  In the above embodiment, the reception means corresponds to the reception circuit 11, the control means corresponds to the power supply control circuit 17, the vehicle state determination means corresponds to the determination processing in S102 of FIG. 8, and the transmission means corresponds to the transmission circuit 12. The processing means corresponds to the DSRC processing unit 13.

  In addition, this invention is not limited to the said embodiment, Based on the meaning of this invention, it can implement with a various form.

  For example, in the above embodiment, the power supply control unit 17 is running or stopped based on the engine speed obtained based on the vibration detected by the vibration sensor 15 and the tilt angle detected by the tilt sensor 16. Although an example of determining whether the vehicle is running or not has been shown, it may be determined whether the vehicle is running or stopped based on the engine speed determined based on the vibration detected by the vibration sensor 15. In this case, when the calculated engine speed is equal to or higher than the predetermined speed, it is determined that the vehicle is traveling, and when it is less than the predetermined speed, it is determined that the vehicle is stopped.

  In the above-described embodiment, the power supply control unit 17 determines whether the vehicle is running or stopped based on the engine speed determined based on the vibration detected by the vibration sensor 15 and the tilt angle detected by the tilt sensor 16. For example, it is provided with a detection circuit for detecting electromagnetic noise generated by spark discharge of an ignition coil during engine operation, and the engine speed is detected based on the electromagnetic noise detected by the detection circuit. To determine whether the engine is operating or stopped. Furthermore, it may be determined that the vehicle is running when the engine speed is equal to or higher than a predetermined speed, and may be determined to be stopped when the engine speed is lower than the predetermined speed.

  Moreover, in the said embodiment, although the example which determines whether the vehicle is drive | working or stopped based on the signal from a vibration sensor and an inclination sensor was shown, for example, the vehicle speed pulse signal output from a vehicle speed sensor Based on the above, it may be determined whether the vehicle is traveling or stopped.

  Further, when the vehicle passes through a continuous communication area as shown in FIG. 11, among the plurality of roadside devices 4 a to 4 b, the intermittent cycle of the power receiving circuit 11 of the vehicle-mounted device 1 is shortened from the front roadside device 4 a (for example, The receiving circuit 11 of the vehicle-mounted device 1 is set so that the intermittent period of the power receiving circuit 11 of the vehicle-mounted device 1 is set longer from the last roadside device 4d (for example, 1 mSEC to 10 mSEC). If the intermittent period is set, it is possible to prevent signals transmitted from the roadside devices 4a to 4d from being missed even when the vehicle travels at a high speed.

  In such a case, the roadside devices 4a to 4d may change the setting of the intermittent period of the receiving circuit 11 of the vehicle-mounted device 1 depending on the content of the service.

  Moreover, a vehicle speed signal may be transmitted from the vehicle-mounted device 1 to the roadside device, and the intermittent period of the receiving circuit 11 of the vehicle-mounted device may be changed according to the speed of the vehicle. In this case, the intermittent cycle may be set short for a vehicle with a high vehicle speed, and the intermittent cycle of the receiving circuit 11 may be set long for a vehicle with a low vehicle speed.

  In the above embodiment, an example in which the intermittent cycle is changed with the intermittent operation time (ON time) of the reception circuit 11 being constant depending on whether the vehicle is running or stopped is described. The ratio between the on time and the off time (duty) may be changed.

  Moreover, in the said embodiment, although the power supply control part 17 showed the example which starts and stops the receiving circuit 11, the DSRC process part 13, and the transmission circuit 12 separately, it is not necessarily required to start and stop separately. The circuit 11, the DSRC processing unit 13, and the transmission circuit 12 may be simultaneously started and stopped simultaneously.

It is a figure which shows the block configuration of the onboard equipment which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the rotation speed of an engine, and the vibration frequency f generate | occur | produced by engine rotation. It is a figure for demonstrating the inclination of the vehicle at the time of decelerating when a vehicle accelerates. It is explanatory drawing when a vehicle stops on an uphill and a downhill. It is explanatory drawing about the basic operation | movement of onboard equipment. It is a schematic explanatory drawing in the case where the vehicle stops in the communication area of the roadside machine and the case where it passes through the communication area at high speed. It is explanatory drawing about the intermittent reception operation | movement of the receiving circuit when a vehicle stops in the communication area of a roadside machine, and when passing a communication area at high speed. It is a flowchart which shows the process of CPU of the power supply control part of onboard equipment. It is a sequence diagram which shows the flow of the signal of DSRC communication between a roadside machine and onboard equipment. It is explanatory drawing about calculation of the consumption current of a receiving circuit. It is explanatory drawing about other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Onboard equipment, 2, 3 ... Vehicle, 4, 4a-4d ... Roadside machine, 11 ... Reception circuit,
12 ... Transmission circuit, 13 ... DSRC processing unit, 14 ... Memory, 15 ... Vibration sensor,
16 ... inclination sensor, 17 ... power supply control unit, 18 ... timer, 19 ... power supply.

Claims (7)

An in-vehicle device that is provided in a vehicle and performs DSRC communication with a roadside device installed on a roadside or the like ,
Receiving means for receiving a signal from the roadside machine; control means for causing the receiving means to receive a signal from the roadside machine intermittently at a predetermined timing;
Vehicle state determination means for determining whether the vehicle is running or stopped, and
When the vehicle state determination unit determines that the vehicle is traveling, the control unit intermittently operates the reception unit at each first intermittent period, and the vehicle state determination unit stops the vehicle. If it is determined that the receiving means is intermittently operated every second intermittent period longer than the first intermittent period ,
The control means transmits information for specifying the moving state of the vehicle to the roadside machine in response to the start of DSRC communication with the roadside machine,
The control means receives information indicating a set value of an intermittent period of the receiving means adapted to the moving state of the vehicle based on information for specifying the moving state of the vehicle from the roadside machine,
Wherein, the vehicle-mounted device, characterized in Rukoto is intermittently operating the receiving unit in the intermittent period in accordance with the information indicating the set value of the intermittent period of the receiving means has received from the roadside device. The in-vehicle device according to claim 1, wherein the control means sets the second intermittent period in a range in which the vehicle does not pass without receiving a signal from the roadside device. . The roadside machine is adapted to change the setting value of the intermittent period of the receiving means according to the content of the service provided by the roadside machine,
3. The vehicle-mounted device according to claim 1, wherein the control unit causes the reception unit to intermittently operate according to information indicating a setting value of an intermittent period of the reception unit that is changed according to the content of the service. . The vehicle state determination means includes a vibration sensor that detects vibration during travel of the vehicle, and the vehicle is traveling or stopped based on the vibration frequency of the vibration detected by the vibration sensor. The vehicle-mounted device according to any one of claims 1 to 3, wherein a determination is made. The vehicle state determination means includes an inclination sensor that detects an inclination angle that changes as the vehicle travels, and is based on the vibration frequency of the vibration detected by the vibration sensor and the inclination angle detected by the inclination sensor. The vehicle-mounted device according to claim 4 , wherein it is determined whether the vehicle is running or stopped. Processing means for performing signal processing of the signal received by the receiving means;
Transmission means for transmitting a signal from the processing means to the roadside machine,
6. The vehicle-mounted device according to claim 1, wherein the control unit starts and stops the reception unit, the processing unit, and the transmission unit separately. It has a battery to supply power,
Vehicle device according to the receiving means and the control unit, any one of claims 1 to 6, characterized in that power is supplied from the battery.

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