JP2012052375A - Electronic key system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic key system capable of exactly identifying the position of an electronic key in a cabin.SOLUTION: In an electronic key system 10, an on-vehicle device 30 including a LF transmission section 42 for transmitting LF to the inside of a cabin is provided in a vehicle, and an electronic key 20 includes: a LF reception section 22 for receiving LF; a LF reception intensity measuring section 24 for measuring the intensity of the LF received by the LF reception section 22; and a UHF transmission section 26 for transmitting intensity information on the LF according to a radio wave intensity V of the LF measured by the LF reception intensity measuring section 24. In the electronic key system 10, the position of the electronic key 20 can be identified based on the intensity information of the LF, and the position of the electronic key 20 in the cabin can be exactly identified.

Description

  The present invention relates to an electronic key system for specifying the position of an electronic key existing in a vehicle interior.

  2. Description of the Related Art Conventionally, in the field of automobile related technology, an electronic key system including an in-vehicle device mounted in a vehicle and an electronic key carried by a user has been put into practical use. In this type of electronic key system, if authentication by wireless communication is established between the vehicle-mounted device and the electronic key, control such as door locking / unlocking and engine starting can be performed without operation with a mechanical key. It is a mechanism that can be executed. That is, when performing these controls, the user does not need to confirm the position as long as he carries the electronic key. Therefore, the electronic key may be lost in the vehicle interior, and an event may occur in which the electronic key is in the vehicle interior, but it is not known where in the vehicle interior. On the other hand, conventionally, an electronic key system capable of specifying the position of the electronic key in the vehicle compartment has already been proposed (see, for example, Patent Document 1).

JP 2008-163633 A

  In the conventional electronic key system, when a radio wave is transmitted from the transmitter included in the vehicle-mounted device to the transmission area (collation area) and a reply from the electronic key is received, it is determined that the collation area has an electronic key, Inform the user of that information. However, in the conventional electronic key system, since the vehicle-mounted device determines only the presence or absence of the electronic key in the verification area, when using the vehicle-mounted device having a relatively wide range in the vehicle interior as the verification area, the verification area It is difficult to specify where the electronic key exists.

  The present invention has been completed based on the above situation, and an object of the present invention is to provide an electronic key system capable of accurately specifying the position of the electronic key in the vehicle interior.

  In the electronic key system of the present invention, an in-vehicle device including an in-vehicle side transmission unit that transmits a first radio wave toward the vehicle interior is provided in the vehicle, and the electronic key is a key side that receives the first radio wave. Receiving means; radio wave intensity measuring means for measuring the intensity of the first radio wave received by the key side receiving means; and response means for transmitting radio wave intensity information corresponding to the radio wave intensity measured by the radio wave intensity measuring means. With.

  In this invention, the electronic key is provided with a radio wave intensity measuring means, and measures the intensity of the received first radio wave. The intensity of the first radio wave is attenuated according to the distance from the transmission source (on-vehicle device, more specifically, the antenna of the on-vehicle device). Therefore, the electronic key can acquire information (distance information) about the distance from the vehicle-mounted device by measuring the intensity of the first radio wave, and use the response means to transmit the distance information to the vehicle-mounted device or the user. You can make a call. The user who has acquired the distance information from the electronic key or the vehicle-mounted device can accurately specify the position of the electronic key in the vehicle interior using the distance information, and can easily detect the electronic key.

  The electronic key of the present invention preferably includes key-side transmission means for transmitting a second radio wave including information according to the radio wave intensity measured by the radio wave intensity measurement means. On-vehicle side receiving means for receiving radio waves from the key-side transmitting means, detecting means for acquiring the radio wave intensity information from the second radio waves received by the on-vehicle side receiving means, and the acquired by the detecting means It is preferable that notifying means for notifying the position of the electronic key based on the radio wave intensity information is provided. Thus, the electronic key can transmit the acquired distance information to the vehicle-mounted device, and the vehicle-mounted device can accurately notify the user of the position of the electronic key in the vehicle interior using this distance information.

  The notification means of the present invention is a flat display capable of displaying a two-dimensional figure, and the flat display includes a vehicle interior figure associated with the space in the vehicle interior, and the vehicle-mounted transmission means in the vehicle interior figure. It is preferable that a region where the electronic key exists with reference to the antenna position is displayed. Thereby, when the notification means notifies the position of the electronic key based on the radio wave intensity information, the presence area corresponding to the acquired distance information can be displayed in a different manner from the other existence areas, A user who visually recognizes the flat display can easily detect the electronic key based on this display.

  It is preferable that a plurality of antennas of the vehicle-mounted side transmission means of the present invention are provided at positions separated in the vehicle front-rear direction in the vehicle interior. In the present invention, the position of the electronic key in the vehicle interior can be accurately specified by using one antenna by arranging the antenna of the vehicle-mounted side transmission means in the center of the vehicle, but a plurality of antennas are used. Thus, even when the antenna of the in-vehicle transmission means is arranged at the end of the vehicle, the position of the electronic key in the vehicle compartment can be accurately specified. In general, the shape of the vehicle compartment is often wider in the front-rear direction of the vehicle than in the width direction of the vehicle, and a plurality of antennas are provided at positions separated in the front-rear direction of the vehicle in the vehicle interior. It is easy to pinpoint the position of the electronic key in the passenger compartment.

  The first radio wave of the present invention is preferably LF. Radio waves have the common property that the intensity is attenuated according to the distance from the transmission source. Among them, LF (long wave) has the property that the intensity of the radio wave is attenuated in inverse proportion to the cube of the distance. ing. That is, the LF has a large change in radio field intensity with respect to a change in distance compared to other radio waves, and can accurately acquire distance information from the measured radio field intensity information. In the present invention, by using LF as the first radio wave, the position of the electronic key in the vehicle interior can be more accurately specified using the distance information acquired with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, in the electronic key system which pinpoints the position of the electronic key which exists in a vehicle interior, the position of an electronic key can be pinpointed correctly.

Block diagram showing the electronic key system 10 The figure which shows the display of the monitor 28 The figure which shows the display of the monitor 28 when the electric key 20 exists in area | region Ea1 The figure which shows the relationship between the reference voltage Vk and intensity range Hk The figure which shows the relationship between the intensity range Hk and the signal pattern Up The figure which shows the relationship between distance and intensity of LF Flow chart showing processing in BCM Flow chart showing processing in electronic key The figure which shows the display of the monitor 28 when the electric key 20 exists in the area | region R

<Embodiment 1>
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1. Configuration of Electronic Key System As shown in FIG. 1, an electronic key system 10 according to the present embodiment includes an electronic key 20 formed by a user and an in-vehicle device 30 provided in the vehicle. The electronic key system 10 performs processing such as door locking, door unlocking, engine starting, and the like by performing wireless communication between the electronic key 20 and the vehicle-mounted device 30, and the position of the electronic key 20 in the vehicle interior. Execute the process to detect.

(About electronic key 20)
The electronic key 20 includes an LF (long wave) receiving antenna 21, an LF receiving unit (an example of a key-side receiving unit) 22, an LF reception intensity measuring unit (an example of a radio wave intensity measuring unit) 24, and a UHF transmitting unit (response unit). And an example of the key side transmission means) 26 and a UHF transmission antenna 28.

  The LF receiver 22 is a wireless receiver (tuner) for receiving LF (an example of a first radio wave) transmitted from the vehicle-mounted device 30 via the LF receiving antenna 21. The LF reception intensity measurement unit 24 is connected to the LF reception unit 22 and measures the intensity V of the LF received by the LF reception unit 22. The LF reception strength measuring unit 24 has a built-in memory, and a plurality of reference strengths Vk are stored in the memory (see FIG. 4). The LF reception intensity measurement unit 24 compares the received LF intensity V with a plurality of reference intensities Vk, and the received LF intensity V exists between a plurality of reference intensities Vk (Vk1> Vk2> Vk3). Of which intensity range Hk belongs to.

  The UHF transmission unit 26 is connected to the LF reception intensity measurement unit 24, acquires the intensity V of the LF measured by the LF reception intensity measurement unit 24, and generates UHF corresponding to the intensity V. The UHF transmitter 26 has a built-in memory, and a plurality of signal patterns Up are stored in the memory in association with each of the plurality of intensity ranges Hk (see FIG. 5). The UHF transmission unit 26 acquires the intensity range Hk determined by the LF reception intensity measurement unit 24, and selects a signal pattern Up stored corresponding to the intensity range Hk. The UHF transmission unit 26 is connected to the UHF transmission antenna 28, and transmits the UHF of the selected signal pattern Up to the vehicle-mounted device 30 via the UHF transmission antenna 28.

(On-vehicle device 30)
The vehicle-mounted device 30 includes a UHF (ultra-high frequency) receiving antenna 31, a UHF receiving unit (an example of on-vehicle side receiving means and detecting means) 32, a BCM (Body electronic Control Machine) 34, a monitor (notifying means). An example) 36, a speaker (another example of the notification unit) 38, an operation unit 40, an LF transmission unit (an example of a vehicle-mounted side transmission unit) 42, and an LF transmission antenna 44 are included.

  The operation unit 40 includes a plurality of buttons such as a start button 40A and a request button 40B, and various input operations such as engine start and detection of the electronic key 20 in the passenger compartment can be performed by the user.

  The LF transmission unit 42 is connected to the BCM 34 and transmits LF based on an instruction from the BCM 34. The LF transmission unit 42 includes two LF transmission antennas 44A and 44B provided in the vehicle, and transmits the LF toward the vehicle interior via the LF transmission antennas 44A and 44B.

  As shown in FIG. 2, the LF transmission antenna 44A is disposed in an instrument panel in the vehicle interior, and the LF transmission antenna 44B is disposed in a rear seat in the vehicle interior. That is, the LF transmission antennas 44A and 44B are provided at positions separated in the front-rear direction of the vehicle in the vehicle interior, and can transmit LF from different positions in the vehicle interior. The LF transmission antennas 44A and 44B are connected to the LF transmission unit 42 by different wirings. Therefore, the LF transmitter 42 can transmit LF at different timings from the LF transmission antennas 44A and 44B.

  The UHF receiving unit 32 is a wireless receiver (tuner) for receiving UHF (an example of a second radio wave) transmitted from the electronic key 20 via the UHF receiving antenna 21. The UHF receiving unit 32 executes processing for acquiring LF intensity information measured by the electronic key 20 from the received UHF. The UHF receiver 32 has a built-in memory, and the memory stores the plurality of signal patterns Up described above. The UHF reception unit 32 identifies the received UHF signal pattern Up by comparing the received UHF with a plurality of signal patterns Up, and acquires the LF intensity information measured by the electronic key 20 from the identified signal pattern Up. To do.

The BCM 34 is connected to each of the above-described units included in the vehicle-mounted device 30 and controls them to execute processing such as door locking.
In addition, the BCM 34 performs a process of detecting the position of the electronic key 20 in the vehicle interior in cooperation with the above-described units. The BCM 34 is connected to the monitor 36 and notifies the position of the electronic key 20 based on the acquired LF intensity information. The monitor 36 is a flat display that displays the two-dimensional figure shown in FIG. 2, and is incorporated in a meter section in the passenger compartment. That is, the monitor 36 is configured by a part of the meter unit. As shown in FIG. 2, the monitor 36 shows a top view of the vehicle with the roof removed, and is associated with the space in the vehicle interior inside the external figure Z1 simulating the external shape of the vehicle. A vehicle interior figure Z2 is shown.

  The monitor 36 also shows the positions of the LF transmission antennas 44A and 44B described above. Concentric circles (dotted lines in FIG. 2) La1, La2, La3, and LF transmission antennas with the position of the LF transmission antenna 44A as a reference. Concentric circles (one-dot chain lines in FIG. 2) Lb1, Lb2, and Lb3 with reference to the position of 44B are shown.

  Concentric circles La1, La2, and La3 indicate positions where the intensity V of the LF transmitted from the LF transmission antenna 44A becomes the reference intensity Vk1, Vk2, and Vk3 (see FIG. 4). As shown in FIG. 6, the intensity V of LF attenuates in inverse proportion to the cube of the distance L from the transmission source (in this case, the LF transmission antenna 44A). Therefore, the region Ea1 from the LF transmission antenna 44A to the concentric circle La1 corresponds to a region where the intensity V of the LF transmitted from the LF transmission antenna 44A is included in the intensity range Hk1. That is, when the LF is transmitted from the LF transmission antenna 44A and the intensity information of the LF acquired by the BCM 34 is included in the intensity range Hk1, it can be understood that the electronic key 20 exists in the area Ea1.

  Similarly, when the LF is transmitted from the LF transmitting antenna 44A and the intensity information of the LF acquired by the BCM 34 is included in the intensity range Hk2, the electronic key 20 exists in the area Ea2 from the concentric circle La1 to the concentric circle La2. When the intensity information of the LF acquired by the BCM 34 is included in the intensity range Hk3, it can be understood that the electronic key 20 exists in the region Ea3 from the concentric circle La2 to the concentric circle La3. That is, the areas Ea1 to Ea3 are determined based on the LF intensity information acquired by the BCM 34, and indicate areas where the electronic key 20 can exist based on the position of the LF transmission antenna 44A.

  The reference strength Vk3 indicates a limit strength at which the electronic key 20 can measure LF. Therefore, when the electronic key 20 exists in the area Ea4 farther from the concentric circle La3, the electronic key 20 cannot measure the intensity V of the LF transmitted from the LF transmission antenna 44A, and the BCM 34 displays the intensity information of the LF. Never get.

  Similarly, concentric circles Lb1, Lb2, and Lb3 indicate positions where the intensity V of LF transmitted from the LF transmitting antenna 44B becomes the reference intensity Vk1, Vk2, and Vk3 (see FIG. 4). Therefore, when LF is transmitted from the LF transmission antenna 44B and the intensity information of the LF acquired by the BCM 34 is included in the intensity range Hk1, the electronic key 20 is placed in the region Eb1 from the LF transmission antenna 44B to the concentric circle Lb1. When it is known that the intensity information of the LF acquired by the BCM 34 is included in the intensity range Hk2, it is understood that the electronic key 20 exists in the region Eb1 from the concentric circle Lb1 to the concentric circle Lb2. When the intensity information of LF acquired by the BCM 34 is included in the intensity range Hk3, it can be seen that the electronic key 20 exists in the region Eb3 from the concentric circle Lb2 to the concentric circle Lb3. That is, the areas Eb1 to Eb3 are determined based on the LF intensity information acquired by the BCM 34, and indicate areas where the electronic key 20 can exist based on the position of the LF transmission antenna 44B.

  When the electronic key 20 exists in the region Eb4 far from the concentric circle Lb3, the electronic key 20 cannot measure the intensity V of the LF transmitted from the LF transmission antenna 44B, and the BCM 34 displays the LF intensity information. Never get.

  The monitor 36 is configured to be able to display the areas Ea1 to Ea3 individually and to be able to display the areas Eb1 to Eb3 individually. Therefore, the BCM 34 displays a corresponding area when notifying the position of the electronic key 20 based on the acquired LF intensity information. For example, when the LF intensity information acquired by the BCM 34 when the LF is transmitted from the LF transmission antenna 44A is Hk1, the area Ea1 is displayed as shown in FIG.

  The BCM 34 is further connected to a speaker 38, and displays the corresponding area as a voice when notifying the position of the electronic key 20 based on the acquired LF intensity information. For example, if the BCM 34 determines that the electronic key 20 is present in the area Ea1 in FIG. 3 based on the acquired LF intensity information, the “electronic key is near the instrument panel” or the like via the speaker 38. And a voice display.

2. Next, with reference to FIGS. 7 and 8, the process of specifying the position of the electronic key 20 present in the vehicle interior of the vehicle will be described.
When the detection start button 36 is pressed by the user, the BCM 34 transmits the LF from the LF transmission antenna 44A toward the vehicle interior using the LF transmission unit 42 (step S2: see line A in FIGS. 7 and 8). The LF receiving unit 22 of the electronic key 20 performs a process of receiving an LF at each reference time (step S22), and ends the process when no LF is received (NO in step S22). On the other hand, when LF is received (YES in step S22), the LF intensity V received by the LF reception intensity measuring unit 24 is measured (step S24). Specifically, the LF reception intensity measurement unit 24 uses the reference intensity Vk to determine which intensity range Hk the received LF intensity belongs to.

  Next, in the electronic key 20, the UHF transmission unit 26 acquires the intensity of the LF measured by the LF reception intensity measurement unit 24, and transmits the UHF corresponding to the intensity to the vehicle-mounted device 30 (step S26: FIG. 7). (See line B in FIG. 8). Specifically, the UHF transmission unit 26 acquires the intensity range Hk determined by the LF reception intensity measurement unit 24, and transmits the UHF of the signal pattern Up stored corresponding to the acquired intensity range Hk.

  In the vehicle-mounted device 30, the BCM 34 controls the UHF receiver 32 to transmit LF (step S 2), and then executes a process of receiving UHF (step S 4) over a certain period of time, and receives UHF. If so (YES in step S4), the LF intensity information measured by the electronic key 20 is acquired from the received UHF (step S14). Specifically, the UHF receiving unit 32 specifies the received UHF signal pattern Up, and acquires LF intensity information measured by the electronic key 20 from the specified signal pattern Up.

  On the other hand, when the UHF is not received for a certain period (NO in step S4), the BCM 34 transmits the LF from the LF transmission antenna 44B toward the vehicle interior using the LF transmission unit 42 (step S6). The processing of the electronic key 20 at this time (steps S22 to S26) is the same as described above, and a duplicate description is omitted.

  In the vehicle-mounted device 30, the BCM 34 controls the UHF receiving unit 32, transmits LF (step S6), and then executes a process of receiving UHF (step S8) for a certain period of time, and receives UHF. If so (YES in step S8), the LF intensity information measured by the electronic key 20 is acquired from the received UHF (step S14). When the BCM 34 acquires LF intensity information (step S14), the BCM 34 displays the areas Ea and Eb corresponding to the intensity information on the monitor 36 (step S16), and the presence of the electronic key 20 is displayed to the user using the speaker 38. The possible area is notified (step S18).

  On the other hand, if the UHF is not received for a certain period (NO in step S4), the BCM 34 determines that the electronic key 20 is not present in the vehicle cabin. The BCM 34 does not display the areas Ea and Eb of the monitor 36 (Step S10), and uses the speaker 38 to inform the user that the electronic key 20 is not present in the vehicle interior (Step S12).

3. Effects of this embodiment According to this embodiment, the following effects can be obtained.
(1) In the electronic key system 10 according to the present embodiment, when the electronic key 20 receives LF, the LF reception intensity measuring unit 24 measures the intensity V of the LF received. The LF strength V correlates with the distance L between the LF transmission antennas 44A and 44B of the LF transmission unit 42 and the electronic key 20, and the LF transmission antenna of the LF transmission unit 42 is measured by measuring the LF strength V. The distance L between 44A, 44B and the electronic key 20 can be acquired. In the electronic key system 10, the position of the electronic key 20 in the vehicle interior can be accurately identified using the acquired distance L, and the electronic key 20 can be easily detected.

(2) In the electronic key 20 of this embodiment, when the LF intensity V received by the LF reception intensity measurement unit 24 is measured, the UHF including the LF intensity information measured by the UHF transmission unit 26 is stored in the vehicle-mounted device. 30. Thereby, the electronic key 20 can transmit the acquired distance information to the vehicle-mounted device 30, and the vehicle-mounted device 30 can accurately notify the user of the position of the electronic key 20 in the vehicle interior using this distance information. it can.

(3) The vehicle-mounted device 30 of the present embodiment has a monitor 36 that is a flat display capable of displaying a two-dimensional figure, and the monitor 36 has a plurality of regions based on the positions of the LF transmission antennas 44A and 44B. Ea and Eb can be individually displayed. Thereby, when the vehicle-mounted device 30 notifies the position of the electronic key 20 based on the transmitted distance information, the areas Ea and Eb corresponding to the acquired distance information are displayed in a different manner from the other areas Ea and Eb. The user who has viewed the flat display can easily detect the electronic key based on this display.

(4) In the vehicle-mounted device 30 of the present embodiment, the LF transmission antennas 44A and 44B are arranged at positions separated in the vehicle front-rear direction in the vehicle interior. As a result, even when the LF transmitting antennas 44A and 44B are arranged at the end of the vehicle that is not assumed to be used by the user, such as inside the instrument panel or inside the rear seat, the position of the electronic key 20 in the passenger compartment is accurately specified. can do. In general, the shape of the passenger compartment of the vehicle is often wider in the front-rear direction of the vehicle than in the width direction of the vehicle, and the LF transmission antennas 44A and 44B are arranged at positions separated in the front-rear direction of the vehicle in the passenger compartment. This makes it easy to accurately identify the position of the electronic key 20 in the passenger compartment.

(5) In the vehicle-mounted device 30 of the present embodiment, when the electronic key 20 is detected, LF is transmitted toward the vehicle interior. The LF has the property that the intensity of the radio wave attenuates in inverse proportion to the cube of the distance, and the change in the radio wave intensity with respect to the change in the distance is larger than that of other radio waves. Distance information can be acquired with high accuracy. In the present embodiment, the position of the electronic key 20 in the passenger compartment can be specified more accurately by detecting the electronic key 20 using LF.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, when the LF is transmitted from the LF transmitter 42 and the electronic key 20 is detected, the LF is transmitted from the LF transmission antenna 44A and the BCM 34 does not receive the UHF. Although the description has been made using an example in which LF is transmitted from the transmission antenna 44B, the present invention is not limited thereto. The LF may be transmitted from the LF transmission antenna 44A regardless of whether or not the LF is transmitted from the LF transmission antenna 44A and the BCM 34 receives the UHF. In this case, it is preferable that the monitor 36 is configured to be able to display the areas Ea1 to Ea3 and the areas Eb1 to Eb3 individually and to be able to display each area closed by the concentric circles La and Lb.

  In this case, for example, the LF intensity information acquired by the BCM 34 when the LF is transmitted from the LF transmission antenna 44A is Hk3, and the LF intensity information acquired by the BCM 34 when the LF is transmitted from the LF transmission antenna 44B. Is Hk2, the ECM 34 displays a region R that is the union of the region Ea3 and the region Eb2, as shown in FIG. For the user, the electronic key can be easily detected by narrowing the detection range of the electronic key.

(2) In the above embodiment, the LF transmission antennas 44A and 44B are arranged inside the instrument panel and the rear seat. However, the places where the LF transmission antennas 44A and 44B are arranged are not limited thereto. For example, an antenna corresponding to processing such as a door lock is often provided near the normal door, and the combined use of this antenna suppresses an increase in the cost of the electronic key system 10. Can do.

(3) In the above embodiment, the electronic key 20 has been described using UHF as a signal for transmitting LF intensity information to the vehicle-mounted device 30. However, the present invention is not limited to this, and other radio waves may be used. However, the normal electric key 20 often stores a UHF transmission IC for instructing a door lock or the like in advance. By using UHF as a signal for transmitting LF intensity information, the electronic key 20 can be used in other ways. It is not necessary to incorporate an IC for transmitting the radio wave, and the cost of the electronic key system 10 can be suppressed from increasing.

DESCRIPTION OF SYMBOLS 10 ... Electronic key system 20 ... Electronic key 22 ... LF receiving part 24 ... LF receiving intensity measuring part 26 ... UHF transmitting part 30 ... Onboard equipment 32 ... UHF receiving part 34 ... BCM
36 ... Monitor 38 ... Speaker 42 ... LF transmitter 44 ... LF transmitter antenna Z2 ... Vehicle interior graphic

Claims (5)

An electronic key system for identifying the position of an electronic key existing in a vehicle cabin,
An on-vehicle device having on-vehicle side transmission means for transmitting a first radio wave toward the vehicle interior is provided in the vehicle, and the electronic key includes key side reception means for receiving the first radio wave, and the key side reception. An electronic key system comprising: radio wave intensity measuring means for measuring the intensity of the first radio wave received by the means; and response means for transmitting radio wave intensity information corresponding to the radio wave intensity measured by the radio wave intensity measuring means.   The response means includes key side transmission means for transmitting a second radio wave including information corresponding to the radio field intensity measured by the radio field intensity measurement means, and the on-vehicle device side has radio waves from the key side transmission means. Based on the radio field intensity information obtained by the detection means, the detection means for acquiring the radio field intensity information from the second radio wave received by the in-vehicle side reception means, and the radio wave intensity information acquired by the detection means. The electronic key system according to claim 1, further comprising notification means for notifying a key position.   The notification means is a flat display capable of displaying a two-dimensional figure, and the flat display includes a vehicle interior figure associated with the space in the vehicle interior, and an antenna position of the vehicle-mounted transmission means in the vehicle interior figure. The electronic key system according to claim 2, wherein an area where the electronic key can be present with reference to the electronic key is displayed.   4. The electronic key system according to claim 2, wherein a plurality of antennas of the on-vehicle side transmission unit are provided at positions separated in the front-rear direction of the vehicle in the vehicle interior.   The electronic key system according to claim 1, wherein the first radio wave is LF.

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