JP2015214316A - Vehicle communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle communication system which can highly precisely detect whether a mobile terminal communicating with a vehicle by means of BLUETOOTH is in or out of the vehicle.SOLUTION: A vehicle communication system performs wireless communication between an on-vehicle control part and a smartphone with BLUETOOTH standards. The on-vehicle control part establishes wireless communication with the smartphone. Whether the smartphone is in or out of the vehicle is determined through the determination whether or not the RSSI of a wireless signal received by the smartphone goes over a reference RSSI. The driving of on-vehicle equipment is permitted on the basis of the position of the smartphone. An antenna 12a on a vehicle side is provided on a floor surface of the vehicle.

Description

  The present invention relates to a vehicle communication system.

  2. Description of the Related Art Conventionally, a vehicle communication system is known that performs wireless communication between a vehicle key and an in-vehicle control unit and executes or permits driving of an in-vehicle device on condition that the wireless communication is established. In addition to the establishment of wireless communication, there is also a vehicle communication system in which driving of an in-vehicle device is executed or permitted only when the position of the vehicle key with respect to the vehicle is in a specific region.

  In the vehicle communication system of Patent Document 1, the vehicle key measures the reception intensity (RSSI) of a signal wirelessly transmitted from an antenna provided on the door handle of the vehicle, and wirelessly transmits the measurement result. The in-vehicle control unit determines the position of the vehicle key based on the measurement result wirelessly transmitted from the vehicle key. In addition to establishment of wireless communication with the vehicle key, the in-vehicle control unit permits switching between locking and unlocking the door when it is determined that the vehicle key is located outside the vehicle.

  Incidentally, there is an in-vehicle communication system that uses a mobile terminal such as a smartphone as a vehicle key instead of a vehicle key dedicated to the vehicle. In the vehicle communication system of Patent Literature 2, wireless communication between a vehicle and a portable terminal is performed using BLUETOOTH (registered trademark), which is one of short-range wireless communication standards.

  In wireless communication (hereinafter referred to as BT communication) by BLUETOOTH, frequency hopping is performed in which the frequency of the 2.4 GHz band (2.40 to 2.48 GHz) divided into 79 or 40 frequency channels is randomly changed.

JP 2012-167446 A JP 2013-106338 A

  In the vehicle communication system of Patent Document 2, driving of the in-vehicle device is permitted regardless of the position of the mobile terminal with respect to the vehicle if wireless communication between the vehicle and the mobile terminal is established. There is also a need to determine permission to drive an in-vehicle device according to the position of the mobile terminal.

  Therefore, as described in Patent Document 1, an antenna for BT communication is provided on the door handle of the vehicle, and the propagation loss values of signals wirelessly transmitted from the antenna are measured at a number of measurement points outside and inside the vehicle. The result was obtained. That is, as shown in the condition D of FIG. 5 and FIG. 11, when the antenna for BT communication is provided on the door handle of the vehicle, the range of the propagation loss value measured at the measurement point outside the vehicle and the measurement point inside the vehicle The range where the measured propagation loss values overlap is wide, and there are many sample points included in the overlapping region. For this reason, there are many misjudgments when trying to determine the position of the mobile terminal relative to the vehicle based on whether or not the reception intensity of the signal received by the mobile terminal exceeds a preset reference intensity. When the position of the mobile terminal is erroneously determined, the operation of the in-vehicle device intended by the user is not executed or permitted, which is difficult to use.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle communication system that detects with high accuracy whether a portable terminal that performs BLUETOOTH communication with a vehicle is located inside or outside the vehicle. Is to provide.

  In order to solve the above problems, a vehicle communication system performs BLUETOOTH standard wireless communication between an in-vehicle device and a portable terminal, establishes wireless communication between the two, and signals of wireless signals transmitted and received between the two In-vehicle control that determines whether the mobile terminal is located inside or outside the vehicle through determination of whether the strength exceeds a preset reference strength, and executes or permits driving of the in-vehicle device according to the position of the mobile terminal The vehicle-side antenna that includes the unit and transmits / receives a BLUETOOTH standard wireless signal is provided on the floor of the vehicle.

  According to this system, a propagation loss value of a radio signal exchanged between a mobile terminal located in the vehicle and the vehicle-side antenna and a radio signal exchanged between the mobile terminal located outside the vehicle and the vehicle-side antenna. The range where the propagation loss value overlaps is narrower than when the antenna is provided on a surface other than the floor. Also, there are few sample points included in the range. As a result, it is possible to determine with high accuracy whether the mobile terminal is located inside or outside the vehicle through the determination of whether the signal strength of the radio signal exchanged between the in-vehicle device and the mobile terminal exceeds a preset reference strength. Can be detected. As a result, the operation of the in-vehicle device intended by the user is easily performed or permitted, so that it is easy to use.

  In the above system, the in-vehicle control unit determines whether or not the signal strength average value of the radio signals for a plurality of channels exchanged between the in-vehicle device and the mobile terminal exceeds a preset reference strength. It is preferable to determine whether the vehicle is located inside or outside the vehicle.

  According to this system, the average value of the propagation loss value of the radio signal exchanged between the mobile terminal located in the vehicle and the vehicle-side antenna, and the exchange between the mobile terminal located outside the vehicle and the vehicle-side antenna. The range of values where the average value of the propagation loss values of radio signals overlaps is narrower than when the average value is not taken. Also, there are few sample points included in the range. Therefore, it is possible to detect whether the mobile terminal is located inside or outside the vehicle with high accuracy.

  In the above system, the in-vehicle control unit transmits / receives the radio signal transmitted / received between the in-vehicle device and the portable terminal when the signal strength of the radio signal deviates from the dynamic range in which the upper and lower limits are set so as to include the reference strength. It is preferable to determine the position of the mobile terminal using the signal strength of the radio signal.

  For example, it is well known that the signal strength is significantly reduced when greatly affected by noise. Therefore, there is a high risk of misjudgment when the significantly reduced signal strength is used to determine the position of the mobile terminal.

  In this regard, according to this configuration, the in-vehicle control unit does not use the signal intensity deviating from the dynamic range for determining the position of the mobile terminal. That is, the position of the mobile terminal is determined using the signal intensity included in the dynamic range. Therefore, it is possible to detect whether the mobile terminal is located inside or outside the vehicle with high accuracy.

In the above configuration, the vehicle-side antenna is preferably provided under the seat on the floor surface including the center console portion.
In the above system, the BLUETOOTH standard is a method for calculating the same antenna mounting and average value for each standard before BT4.0 with a fast channel switching time and for Low Energy with a slow channel switching time. Is preferred.

  The vehicle communication system of the present invention has an effect of detecting, with high accuracy, whether a portable terminal that performs BLUETOOTH communication with a vehicle is located inside or outside the vehicle.

The block diagram which shows schematic structure of a vehicle communication system. The top view of the vehicle which shows the mounting area of a communication area and an antenna. The side view of the vehicle which shows the mounting position of an antenna. The graph which shows the result of having measured the propagation loss of the 2.4GHz band radio wave transmitted by radio | wireless from the antenna provided in the floor surface of a vehicle in a certain measurement point. A graph showing the propagation loss of 2.4 GHz band radio waves over all channels, the relationship between the range of the average value and the sampling point, and the relationship between the range of the average value and the mounting position of the antenna . The graph which shows the relationship between the propagation loss at the time of judging with one sample among the propagation losses measured outside the vehicle interior when installing an antenna on the floor, and the detection frequency of the value. The graph which shows the relationship between the average value of a propagation loss when judging with two samples among the propagation losses measured outside a vehicle interior, when an antenna is installed in a floor surface, and the detection frequency of the value. The graph which shows the relationship between the average value of a propagation loss when determining with three samples among the propagation loss measured outside a vehicle interior, when an antenna is installed in a floor surface, and its detection frequency. The graph which shows the relationship between the average value of a propagation loss when judging with five samples among the propagation loss measured outside a vehicle interior, when an antenna is installed in a floor surface, and the detection frequency of the value. The graph which shows the result of having measured the propagation loss of the 2.4GHz band radio wave transmitted by radio | wireless from the antenna provided in the floor surface of a vehicle in a certain measurement point. The graph which shows the relationship between the propagation loss at the time of judging with one sample among the propagation loss measured outside and the vehicle interior when an antenna is installed in a door handle, and the detection frequency of the value. The graph which shows the relationship between the number of samples for calculating the average value used for determination, and a misjudgment rate.

Hereinafter, an embodiment of a vehicle communication system will be described with reference to the drawings.
As shown in FIG. 1, the vehicle communication system 1 performs vehicle control through wireless communication between the vehicle 10 and the smartphone 20.

<Smartphone>
As shown in FIG. 1, the smartphone 20 includes a smartphone control unit 21, a BLUETOOTH (registered trademark) communication unit (hereinafter referred to as a BT communication unit) 22, a public line communication unit 24, a microphone 25, a speaker 26, and a touch panel. And a display 27. The BT communication unit 22, the public line communication unit 24, the microphone 25, the speaker 26, and the touch panel display 27 are each electrically connected to the smartphone control unit 21 and are comprehensively controlled by the smartphone control unit 21.

  The BT communication unit 22 is mounted on other devices by performing frequency hopping that randomly changes the frequency of the 2.4 GHz band (2.40 to 2.48 GHz) divided into 79 or 40 frequency channels. BLUETOOTH communication (hereinafter referred to as BT communication) is performed with the BT communication unit that is present. Here, the BT communication includes both a classic type using 79 ch and a low energy type using 40 ch. The BT communication unit 22 converts the electrical signal generated by the smartphone control unit 21 into a 2.4 GHz band radio signal and wirelessly transmits the radio signal toward a preset communication area through the BT antenna 22a. The BT communication unit 22 converts a 2.4 GHz band radio signal received through the BT antenna 22a into an electrical signal. The BT communication unit 22 includes an RSSI circuit 22b that detects an RSSI (signal strength) of a radio signal received via the BT antenna 22a.

  The public line communication unit 24 is connected to a public line such as 3G or LTE, and performs desired wireless communication. The microphone 25 picks up a sound wave and converts it into an electric signal. The speaker 26 converts the electric signal into a sound wave. The touch panel display 27 radiates and converts the information indicating the touch position into an electrical signal and displays an image based on the signal generated by the smartphone control unit 21, but is not the gist of the present invention.

  The memory 21 a of the smartphone control unit 21 stores a BT device address unique to itself and an ID code common to the vehicle-mounted control unit 11 provided in the vehicle 10. The BT device address is used for pairing processing and BT communication with a communication partner having a BT communication unit. The ID code is used for mutual authentication with the in-vehicle control unit 11. The smartphone control unit 21 searches for a device capable of pairing, a BT communication enabled mode in which BT communication is enabled with a paired communication partner, a BT communication disabled mode in which BT communication is disabled, and And a search mode. Switching between these three modes is performed by operating the touch panel display 27.

  When the smartphone control unit 21 in the search mode finds a device that can be paired, it performs a pairing process. When the pairing process is completed, the smartphone control unit 21 can perform BT communication with the paired communication partner. The communication partner is specified by a code unique to the communication partner. In order to ensure security, the pairing process may require the entry of a personal identification number unique to the communication partner. Once the personal identification number is entered, pairing can be performed without entering the personal identification number thereafter. Sometimes allowed. In some cases, pairing is permitted without entering a password once.

  In the BT communication enabled mode, when the smartphone control unit 21 paired with the in-vehicle control unit 11 receives the request signal for requesting the transmission of the ID code and the RSSI, the RSSI of the request signal is transmitted through the RSSI circuit 22b. To detect. And the vehicle-mounted control part 11 produces | generates the response signal containing each information of ID code memorize | stored in own memory 21a and the detected RSSI as a response with respect to a request signal, and transmits this wirelessly.

<Vehicle>
As shown in FIG. 1, the vehicle 10 includes an in-vehicle control unit 11, a BLUETOOTH communication unit 12, an engine switch 13, an engine control device 14, a door handle sensor 15, and a door lock device 16. . The BT communication unit 12, the engine switch 13, the engine control device 14, the door handle sensor 15, and the door lock device 16 are each electrically connected to the in-vehicle control unit 11 and are comprehensively controlled by the in-vehicle control unit 11. The

  The BT communication unit 12 performs BLUETOOTH communication with other BT communication units by performing frequency hopping in the 2.4 GHz band. The BT communication unit 12 converts the electrical signal generated by the in-vehicle control unit 11 into a 2.4 GHz band signal. The converted radio signal is wirelessly transmitted through the BT antenna 12a toward the communication area S set in advance so as to cover the entire vehicle 10, as shown in FIG. The communication area S in FIG. 2 is an area of about 1 m around the vehicle, but can be set to an area of about 10 to 100 m around the vehicle by adjusting the BT output. The BT communication unit 12 converts a 2.4 GHz band radio signal received through the BT antenna 12a into an electrical signal.

  Here, as shown in FIGS. 2 and 3, the BT antenna 12a is installed under the seat of the driver's seat and on the floor surface. Further, the BT antenna 12a is installed such that the direction of the linearly polarized wave faces the front-rear direction of the vehicle.

As shown in FIG. 1, the engine switch 13 detects a pressing operation.
The engine control device 14 controls starting and stopping of the engine.
The door handle sensor 15 detects contact with the door handle.

The door lock device 16 switches between locking and unlocking the door.
In the memory 11 a of the in-vehicle control unit 11, a unique BT device address and personal identification number, and an ID code common to the smartphone control unit 21 provided in the smartphone 20 are stored. The device address and password of the BT are used for pairing processing with a communication partner having a BT communication unit. The ID code is used for mutual authentication with the smartphone control unit 21.

  Furthermore, the past five RSSIs received from the smartphone control unit 21 are stored in the memory 11a. The memory 11a stores a reference RSSI that is set in advance to determine the position of the smartphone 20 with respect to the vehicle 10. The reference RSSI is set for each vehicle based on data sampled at a number of survey points. Further, the memory 11 a stores a dynamic range for determining whether to use the RSSI detected by the smartphone 20 in order to determine the position of the smartphone 20 with respect to the vehicle 10. The upper and lower limits of the dynamic range are set for each vehicle based on data sampled at a number of survey points so as to include the reference RSSI. The dynamic range here is set to be ± 30 dB of the reference RSSI. The reference RSSI corresponds to the reference intensity.

  The in-vehicle control unit 11 has a BT communication enable mode in which BT communication is possible with a communication partner with which pairing has been established, and a BT communication disable mode in which BT communication is disabled. . Switching between the BT communication enabled mode and the BT communication disabled mode is performed by operating an input device (not shown).

  Note that the in-vehicle control unit 11 in the BT communication enable mode is in a state that can be paired with a device having the BT communication unit, and is paired with the device by being discovered by the searching device and subjected to pairing processing. The When the pairing process is completed, the in-vehicle control unit 11 can perform BT communication with the paired communication partner. The communication partner is specified by a code unique to the communication partner. In addition, the vehicle-mounted control part 11 calculates | requires the input of a PIN code in the case of a pairing process. When a personal identification number is input to itself, pairing with a device having the personal identification number is permitted.

  In the BT communication enabled mode, the in-vehicle control unit 11 paired with the smartphone control unit 21 periodically generates a request signal for requesting transmission of an ID code and transmission of RSSI, and wirelessly transmits the request signal. When receiving the response signal as a response to the request signal, the in-vehicle control unit 11 collates the ID code included in the response signal with the ID code stored in its own memory 11a. When collation is established, the RSSI included in the received response signal is stored instead of the oldest data among the past five RSSIs stored in the memory 11a, and the last five stored times are stored. The average value of RSSI is calculated. When the RSSI average value for the latest five times exceeds the reference RSSI, the in-vehicle controller 11 determines that the smartphone 20 is located in the vehicle compartment and permits the engine to start. When the engine switch 13 detects an operation in this state, the in-vehicle control unit 11 starts the engine through the engine control device 14. On the other hand, when the RSSI average value for the latest five times does not exceed the reference RSSI, that is, when the RSSI is small, the in-vehicle controller 11 determines that the smartphone 20 is located outside the vehicle compartment, and locks and unlocks the door. Allow switching with lock. When the door handle sensor 15 detects contact in a state where switching between locking and unlocking of the door is permitted, the in-vehicle control unit 11 switches between locking and unlocking the door through the door locking device 16.

  Here, when the RSSI included in the response signal is not included in the dynamic range, the vehicle-mounted control unit 11 does not store the RSSI in the memory 11a, and uses the RSSI included in the response signal for the latest five times. The RSSI average value is calculated.

<Action>
Next, the operation of the vehicle communication system 1 will be described.
First, FIG. 4 shows the result of measuring the propagation loss of a 2.4 GHz band (2.40 to 2.48 GHz) radio wave wirelessly transmitted from an antenna provided on the floor of the vehicle at a certain measurement point. As shown in FIG. 4, the propagation loss is difficult to be flat because there is reflection in a vehicle that is a metal body.

  Therefore, the inventor of the present case has changed the propagation loss in all channels (here, 79 channels) wirelessly transmitted from the antenna while changing the mounting position of the antenna on the vehicle at 100 or more measurement points outside and inside the vehicle interior. Were measured and the average value of these was calculated. Propagation loss and RSSI are different amounts of material, but when transmission power is constant, they are in a proportional relationship and can be used as alternative characteristics. And the range which an average value can take was calculated | required. The result is shown in FIG. Condition A is when the antenna is installed on the B-pillar, Condition B is when the antenna is installed on the floor under the seat of the driver's seat and the linear polarization of the antenna faces the vehicle width direction, and Condition C is the antenna Is installed on the floor under the seat of the driver's seat so that the linearly polarized wave of the antenna faces in the vehicle front-rear direction, the condition D is when the antenna is installed on the door handle.

  As shown in FIG. 5, the condition B and the condition C are compared with the condition A and the condition D in the range of the propagation loss measured at the measurement point outside the passenger compartment and the range of the propagation loss measured at the measurement point in the passenger compartment. The range where the and overlap. Therefore, in the condition B and the condition C, a value having a propagation loss is defined as a reference value, and the measurement point at which the reference value is measured through whether or not the propagation loss obtained by measuring the reference value is located is either inside or outside the vehicle interior. If you decide to do so, there is little risk of misjudgment.

  Note that, in conditions B and C, although the direction of polarization of the antenna is different, the range of propagation loss measured at a measurement point outside the passenger compartment overlaps with the range of propagation loss measured at the measurement point inside the passenger compartment. Are the same size. That is, if the antenna is installed on the floor of the vehicle 10, the position of the smartphone 20 can be determined more accurately from the propagation loss, in other words, RSSI. Note that, in the case of linear polarization in the longitudinal direction of the vehicle (condition C), the amount of diffraction at the door is reduced in principle, which is more effective.

By the way, in order to calculate the average value of all channels, it is necessary to send and receive signals in all channels, so it takes time to calculate the average value.
Therefore, the inventor of the present case examined the relationship between the number of samples for calculating the average value and the misjudgment rate when calculating the average value. The results are shown in FIGS. FIG. 6 shows the relationship between the propagation loss when judging with one sample and the detection frequency of the value, and FIG. 7 shows the relationship between the average value of propagation loss when judging with two samples and the detection frequency of the value. , Respectively. FIG. 8 shows the relationship between the average value of propagation loss when determining with three samples and the detection frequency of the value, and FIG. 9 shows the average value of propagation loss when detecting with five samples and the detection of the value. The relationship with frequency is shown respectively.

  As shown in FIGS. 6 to 9, the misjudgment rate tends to decrease as the number of samples for calculating the average value of propagation loss increases. However, when the number of samples exceeds 3, the tendency of the misjudgment rate to decrease deteriorates. That is, as can be seen from FIG. 12, even if the average value of the propagation loss is obtained from three or more samples, the error determination rate is not improved so much. Therefore, if the position of the smartphone 20 is determined from the average value of the propagation loss (RSSI) of the three samples, the position of the smartphone 20 is determined from the average value of the propagation loss (RSSI) of all channels. There is no significant deterioration and the accuracy rate can be secured. Furthermore, the time taken to determine the position of the smartphone 20 is short. In particular, the case of Low Energy is effective.

  Note that, as indicated by a circle in FIG. 10, depending on the position of the measurement point, a region where the propagation loss is extremely larger than the surrounding frequencies at a specific frequency may be sampled. If the measurement value in such a case is employed to determine the average value when determining the position of the previous smartphone 20, the average value may be extremely reduced. In this case, the risk of erroneously determining the position of the smartphone 20 increases. In this respect, in the present example, such a measurement value is not added to the sample for determining the position of the smartphone 20, so that there is a low possibility that the position of the smartphone 20 is erroneously determined.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) The antenna 12 a is installed on the floor of the vehicle 10. When the antenna is installed on the floor surface, there is a range in which the propagation loss value of the wireless signal received by the smartphone 20 located inside the vehicle and the propagation loss value of the wireless signal received by the smartphone 20 located outside the vehicle overlap. Narrower than before. Thereby, it is possible to detect with high accuracy whether the smartphone 20 is located inside the vehicle or outside the vehicle through the determination whether the RSSI of the wireless signal detected by the smartphone 20 exceeds the preset reference RSSI. As a result, since the operation of the in-vehicle device intended by the user is easily permitted, it is easy to use.

  (2) The in-vehicle controller 11 determines whether the smartphone 20 is located inside or outside the vehicle depending on whether or not the RSSI average value of the five channels exchanged with the smartphone 20 exceeds the reference strength. It was configured as follows. Compared with the case where the average value of a plurality of samples is determined from one sample in this way, the propagation loss value of the radio signal transmitted and received between the smartphone 20 located in the vehicle and the antenna 12a, and the outside of the vehicle The range in which the propagation loss value of the radio signal transmitted and received between the smartphone 20 and the antenna 12a overlaps is narrower than before. Thereby, it can be detected with higher accuracy whether the smartphone 20 is located inside the vehicle or outside the vehicle.

  (3) Moreover, compared with the case where the position of the said smart phone 20 is determined after calculating the average value of RSSI of all the channels received with the smart phone 20, the time concerning determination is also short. In particular, in Bluetooth Low Energy, since the time for channel switching is long, the time required for determination is shorter than taking the average of RSSI of all channels.

  (4) Since the antenna 12a is installed under the seat of the driver's seat on the floor, the antenna 12a is unlikely to hit the user's foot and a space for mounting the antenna 12a is easily secured. Thereby, the vehicle-mounted control part 11 can detect the position of the smart phone 20 by reference | standard RSSI with high precision.

In addition, you may change the said embodiment as follows.
-In the said embodiment, the direction of the linearly polarized wave of the antenna 12a is not limited to the front-back direction of a vehicle.

  -In the said embodiment, the position where the antenna 12a is installed is not limited under the seat of a driver's seat. As long as the antenna 12a is installed on the floor, the antenna 12a may be under the passenger seat, the center console, or under the rear seat.

In the above embodiment, the dynamic range does not necessarily have to be set.
In the above embodiment, the number of RSSI samples for calculating the average value is not limited to five. As the number of RSSI samples for calculating the average value increases, the misjudgment rate decreases.

  -In above-mentioned embodiment, even if the sample of RSSI is one, you may determine the position of the smart phone 20 through the comparison with the one RSSI and reference | standard RSSI. If the antenna 12a is installed on the floor surface of the vehicle, the position of the smartphone 20 can be determined with high accuracy.

In the above-described embodiment, the pairing request signal is wirelessly transmitted from the smartphone 20 and the pairing response signal is wirelessly transmitted from the vehicle-mounted control unit 11, respectively, but the reverse may be possible.
In the above-described embodiment, the smartphone 20 is used as the mobile terminal, but instead of this, a tablet terminal that does not have a telephone function, a portable music terminal, a notebook computer, or the like may be used.

  In the above embodiment, the antenna 12a may be a patch antenna, an inverted L antenna, an inverted F antenna, a dipole antenna, a monopole antenna, etc., and is not particularly limited in directivity. There is no particular limitation on polarization.

  In the above-described embodiment, the BLUETOOTH standard may be any of the standards before BT4.0 having a fast channel switching time and Low Energy having a slow channel switching time. Regardless of which standard is adopted, the antenna mounting position and the RSSI average value calculation method may be the same as those in the embodiment and the other example.

Next, the technical idea conceived from the embodiment and the other examples will be described.
(A) In the above system, it is preferable that the vehicle-side antenna is provided so that the linearly polarized wave faces in the front-rear direction of the vehicle.

  According to this system, compared with a case where the direction of linearly polarized waves is directed to a direction other than the front-rear direction of the vehicle, a radio signal transmitted and received between the mobile terminal located in the vehicle and the vehicle-side antenna The range in which the propagation loss value of the wireless signal and the propagation loss value of the radio signal exchanged between the mobile terminal located outside the vehicle and the vehicle-side antenna overlap is narrow. Also, there are few sample points included in the range. Therefore, it can be detected with high accuracy whether the portable terminal is located inside the vehicle or outside the vehicle.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle communication system, 10 ... Vehicle, 11 ... Car-mounted control part, 12, 22 ... BT communication part, 12a, 22b ... BT antenna, 20 ... Smartphone, 22b ... RSSI circuit.

Claims (5)

Whether or not the BLUETOOTH standard wireless communication is performed between the in-vehicle device and the portable terminal, the wireless communication between the two is established, and whether the signal strength of the wireless signal exchanged between the two exceeds a preset reference strength In the vehicle communication system comprising an in-vehicle control unit that determines whether the mobile terminal is located inside or outside the vehicle through the determination of, and executes or permits the driving of the in-vehicle device according to the position of the mobile terminal,
The vehicle-side antenna that transmits and receives a BLUETOOTH standard wireless signal is a vehicle communication system provided on the floor of the vehicle. The vehicle communication system according to claim 1,
The in-vehicle control unit determines whether the mobile terminal is inside or outside the vehicle by determining whether or not the signal strength average value of a plurality of channels transmitted and received between the in-vehicle device and the mobile terminal exceeds a preset reference strength. The vehicle communication system which judges which is located. The vehicle communication system according to claim 1 or 2,
If the signal strength of the radio signal transmitted / received between the in-vehicle device and the mobile terminal deviates from the dynamic range in which the upper and lower limits are set so that the reference strength is included, the in-vehicle control unit A vehicle communication system that determines the position of a mobile terminal using signal strength. In the vehicle communication system according to any one of claims 1 to 3,
The vehicle-side antenna is a vehicle communication system provided under a seat on a floor surface including a center console portion. In the vehicle communication system according to any one of claims 1 to 4,
The BLUETOOTH standard is a vehicle communication system which is a method of calculating the same antenna mounting and average value in any of the standards before BT4.0 having a fast channel switching time and Low Energy having a slow channel switching time.