JP2015045123A - Electronic key position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic key position detecting device improved in electronic key position detection accuracy by a small number of antennas.SOLUTION: An electronic key position detecting device 1 for detecting a position of an electronic key 100 which can be carried by a user and is communicated with an on-vehicle machine mounted on a vehicle so as to perform collation of an ID code includes: a first transmission antenna 21 provided on the vehicle; a second transmission antenna 22 provided in a position separated from the first transmission antenna; a third transmission antenna 23 provided in a position separated from a straight line connecting the first and the second transmission antennas; a receiving antenna 24; and position determination means 10 for performing transmission to the electronic key sequentially for each of the antennas while varying output of the first to the third transmission antennas, and determining the position of the electronic key with respect to the vehicle body on the basis of the output by which the electronic key can receive electric waves transmitted by the first to the third transmission antennas.

Description

  The present invention relates to an electronic key position detection device provided in a vehicle such as an automobile, and more particularly to an apparatus for improving the position detection accuracy of an electronic key with a small number of antennas.

In order to improve operability, convenience, and theft protection in vehicles such as automobiles, ID codes are collated between on-board devices and electronic keys, and when the collation is established, the engine is started and the door lock is unlocked. Electronic key (smart key) systems that make possible are widespread.
In such an electronic key system, it is necessary to vary the available operations depending on whether the electronic key is located inside the vehicle compartment or outside the vehicle compartment.
For example, starting of a driving power source such as an engine is permitted only when an electronic key is present in the vehicle interior, and locking of the door lock is permitted only when the electronic key is present outside the vehicle interior.

For this reason, the electronic key system is required to accurately detect the position of the electronic key.
As a conventional technique for detecting the position of the electronic key, an antenna is provided outside the vehicle interior, and whether the electronic key is in the vehicle interior or the vehicle exterior is determined based on whether or not each antenna can communicate with the electronic key. It has been known.
Patent Document 1 describes that when an antenna provided in a vehicle interior does not receive a high-frequency signal from a smart key, the user is informed that the smart key has been taken out by the passenger. ing.
Further, in Patent Document 2, verification communication areas are formed on the driver's seat side and the passenger's seat side, respectively, and it is determined whether the electronic key exists outside the vehicle compartment or in the vehicle interior by a combination of these verification possible / impossible. It is described.

JP2013-23010A JP 2012-177243 A

In the above-described prior art, it is possible to determine whether or not the electronic key is present in the vehicle interior, but it has not been possible to detect the position in the vehicle interior.
For this reason, when the user forgets to put the electronic key in a storage unit such as a glove box or a bag, or when the electronic key falls on the floor, the location of the electronic key becomes unknown.
On the other hand, if a large number of antennas are installed, the position detection accuracy of the electronic key can be improved, but in this case, the configuration of the apparatus becomes complicated.
In view of the above-described problems, an object of the present invention is to provide an electronic key position detection device that improves the position detection accuracy of an electronic key with a small number of antennas.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is an electronic key position detection device for detecting the position of an electronic key that is portable by a user and communicates with an onboard unit mounted on the vehicle to collate an ID code. A first transmission antenna for transmitting a radio wave received by the electronic key, a second transmission antenna provided at a position away from the first transmission antenna of the vehicle, and the first of the vehicle. A third transmitting antenna provided at a position separated from a straight line connecting the second transmitting antenna and the second transmitting antenna; a receiving antenna provided in a vehicle for receiving radio waves transmitted by the electronic key; Transmission to the electronic key is sequentially performed for each antenna while changing the output of the third antenna, and radio waves transmitted by the first to third antennas are respectively transmitted to the electronic key. There is an electronic key position detecting device characterized by comprising a position determining means for determining a position of the electronic key relative to the vehicle body based on the minimum output can be received.
According to this, the minimum output at which the electronic key can receive the radio waves transmitted by the first to third transmitting antennas is detected, the distance from each transmitting antenna to the electronic key is estimated, and the estimated distance and By identifying the position of the electronic key from the coordinates of each transmission antenna, not only can the electronic key be located outside or inside the vehicle interior, but also where the electronic key is located inside or outside the vehicle interior using a small number of antennas. Can be detected.

According to a second aspect of the present invention, the position determination unit is configured to transmit the radio waves transmitted by the first to third transmission antennas from each transmission antenna to the electronic key according to a minimum output at which the electronic key can receive each radio wave. The electronic key position detecting device according to claim 1, wherein the position of the electronic key is determined by estimating each distance of the electronic key.
According to this, the effect mentioned above can be acquired more reliably.

According to a third aspect of the present invention, the position determination means holds information related to the receivable range of the electronic key according to the outputs of the first to third transmission antennas, and the first to third antennas transmit the information. 2. The electronic key position detecting device according to claim 1, wherein a region where an outer edge of a receivable range corresponding to a minimum output at which the electronic key can receive radio waves to be superimposed is determined as a position of the electronic key. It is.
According to this, even when there is an influence of radio wave shielding due to various parts, for example, the position detection accuracy of the electronic key is further improved by preliminarily storing information on the communicable range reflecting the influence. can do.

According to a fourth aspect of the present invention, the position determination means decreases the output change amount when sequentially changing the outputs of the first to third transmission antennas as the number of times the output change is performed increases. The electronic key position detecting device according to any one of claims 1 to 3, wherein the electronic key position detecting device is an electronic key position detecting device.
According to this, the lower limit output at which communication is established can be detected early, and the position detection of the electronic key can be speeded up.

The invention according to claim 5 has a notifying means for notifying a user of the position of the electronic key determined by the position determining means. This is an electronic key position detecting device.
According to this, the convenience of the vehicle can be improved by notifying the user of the position of the electronic key.

  As described above, according to the present invention, it is possible to provide an electronic key position detection device that improves the position detection accuracy of an electronic key with a small number of antennas.

It is a block diagram which shows the structure of the Example of the electronic key position detection apparatus to which this invention is applied. It is a typical top view of vehicles provided with the electronic key position detection device of an example. It is a flowchart which shows operation | movement of the electronic key position detection apparatus of an Example.

  An object of the present invention is to provide an electronic key position detection device that improves the position detection accuracy of an electronic key with a small number of antennas. The minimum antenna output that enables communication with an electronic key when the output of each antenna is changed. Based on the above, it was solved by estimating the distance from each antenna to the electronic key and detecting the electronic key position.

Embodiments of an electronic key position detection apparatus (hereinafter simply referred to as “position detection apparatus”) to which the present invention is applied will be described below.
The position detection device of the embodiment is provided in an automobile such as a passenger car, for example, and is unlocked by a user and carried out by collating an ID code with a collation control unit mounted on the vehicle side and driving power. The position of the electronic key enabling the activation of the source is detected.

FIG. 1 is a block diagram illustrating a configuration of the position detection device according to the embodiment.
The position detection device 1 of the electronic key 100 includes a collation control unit 10, a right front transmission antenna 21, a left front transmission antenna 22, a rear transmission antenna 23, a vehicle reception antenna 24, and the like, and further includes an engine control unit 30 and a vehicle body integration. A unit 40, a display device 50, a key search operation unit 60, and the like are connected.

The collation control unit 10 communicates with the electronic key 100 via the antennas 21 to 24 to collate the ID code.
The ID code verification is performed by the vehicle receiving antenna 24 receiving the radio wave transmitted by the transponder of the electronic key 100 that has received the LF radio wave transmitted from each of the transmission antennas 21 to 23 to the RF radio wave. This is done by transmitting to the control unit 10.
The verification control unit 10 determines whether or not the electronic key 100 is authorized based on the signal received by the vehicle receiving antenna 24.
The collation control unit 10 includes information processing means such as a CPU, storage means such as RAM and ROM, communication means for communicating with the electronic key 100 via the antennas 21 to 24, an input / output interface, and a bus connecting them. Etc.
The collation control unit 10 has a function of performing communication by changing the outputs of the transmission antennas 21 to 23 individually.

The collation control unit 10 has an output-collation range database 11 inside the storage means.
The output-verification possible range database 11 provides information on a range that can be communicated with and collated with the electronic key 100 when each of the transmission antennas 21 to 23 has a predetermined output, for each antenna output in a plurality of stages. keeping.
This point will be described in detail later.

The right front transmission antenna 21, the left front transmission antenna 22, the rear transmission antenna 23, and the vehicle reception antenna 24 are arranged in the vehicle interior of the vehicle and communicate with the electronic key 100.
FIG. 2 is a schematic plan view of a vehicle having the position detection device of the embodiment.
The vehicle 200 has a passenger compartment (cabin) 210 in which a passenger gets in the center of the vehicle body.
Inside the passenger compartment 210, a right front seat 220, a left front seat 230, a rear seat 240, an instrument panel 250, a center console 260, and the like are provided.

The right front seat 220 and the left front seat 230 are seats arranged in the vehicle width direction at the front portion of the passenger compartment 210.
The rear seat 240 is, for example, a bench seat for three people arranged at the rear of the passenger compartment 210.
The instrument panel 250 is an interior member disposed in front of the right front seat 220 and the left front seat 230.
The center console 260 is an interior member that protrudes from the center of the instrument panel 250 in the vehicle width direction to the vehicle rear side.
The rear portion of the center console 260 is disposed between the right front seat 220 and the left front seat 230.

The right front transmission antenna 21 is disposed in a region adjacent to the right front seat 220 on the right inner surface of the passenger compartment 210.
The left front transmission antenna 22 is provided in a region adjacent to the left front seat 230 on the left inner surface of the passenger compartment 210.
The rear transmission antenna 23 is disposed at the center in the vehicle width direction at the rear end of the passenger compartment 210.
A straight line connecting the right front transmission antenna 21 and the left front transmission antenna 22 is disposed substantially along the vehicle width direction, and the rear transmission antenna 23 is disposed at a position spaced rearward from the straight line.
The vehicle receiving antenna 24 is disposed at an arbitrary position in the passenger compartment 210. For example, the vehicle receiving antenna 24 can be provided at the center of the instrument panel 250.

The output-verification range database 11 described above holds information regarding the collation possible range (communication range) in a plurality of stages of antenna output for each of the transmission antennas 21 to 23.
Regions A <b> 1 to A <b> 3 illustrated in FIG. 2 indicate collation possible ranges when the output of the right front transmission antenna 21 is sequentially increased.
The outer edge of the collable range is substantially spherical with the transmission antenna as the center when there is no object that shields radio waves between it and the transmission antenna. For example, the seat back (backrest) of the right front seat 220 In the case where an object having the property of shielding radio waves is interposed as in the above, in a region where the output of the antenna is small, the radio waves are shielded and cannot be collated farther than the object. In this case, the collation can be performed at a distance farther than the object only when the output of the transmission antenna is increased to some extent, but the range in which the collation can be performed is narrower than the case where no object is interposed.
The output-verifiable range database 11 holds data related to the outer edge of the collable range in a plurality of stages of antenna output for each of the transmission antennas 21 to 23.
Such a collable range can be obtained in advance by experiments or simulations, for example.

The engine control unit 30 comprehensively controls an engine that is a driving power source for the vehicle and its auxiliary equipment.
When the verification of the ID code of the electronic key 100 is established in the verification control unit 10, the engine control unit 30 permits the engine to be started in response to an operation of an engine start switch (not shown).

The vehicle body integration unit 40 controls the various electrical components provided on the vehicle body in an integrated manner.
A door lock actuator 41 is connected to the vehicle body integration unit 40.
The door lock actuator 41 is an electric actuator such as a solenoid that locks and unlocks the door lock mechanism of the vehicle.
When the collation control unit 10 collates the ID code of the electronic key 100, the vehicle body integration unit 40 controls the door lock actuator 41 to unlock and lock the door lock mechanism.

The display device 50 is an image display device such as an LCD provided in the instrument panel 250 or the like.
The key search operation unit 60 is provided on the instrument panel 250 or the like, and inputs an operation for searching for the location of the electronic key 100 when the user is uncertain.

Hereinafter, the detection operation of the position detection device described above will be described.
FIG. 3 is a flowchart illustrating the operation of the electronic key position detection device according to the embodiment.
This process is executed when a predetermined search operation is input from the key search operation unit 60.
Hereinafter, the steps will be described step by step.
First, the processing from steps S01 to S08 is sequentially performed for each of the transmission antennas 21 to 23.
<Step S01: Formation of collation communication area with maximum antenna output>
The collation control unit 10 forms a collation communication area by transmitting LF radio waves with the antenna output being maximized, and tries to communicate with the electronic key 100 and collate the ID code.
Thereafter, the process proceeds to step S02.

<Step S02: Determination of ID verification establishment>
The verification control unit 10 determines whether or not ID code verification is established.
If ID code verification is not established, the process proceeds to step S03. If established, the process proceeds to step S04.

<Step S03: Implementation with the next antenna>
The collation control unit 10 ends the formation of the collation communication area by terminating the transmission of the LF radio wave by the antenna that has just attempted the ID code collation, and repeats the processes after S01 with the next antenna.

<Step S04: Reduction of antenna output>
The collation control unit 10 reduces the antenna output by a predetermined value and forms a collation communication area again.
Thereafter, the process proceeds to step S05.

The processes in steps S05 to S07 described below are repeated a plurality of times (for example, X times).
<Step S05: Determination of ID verification establishment>
The verification control unit 10 determines whether or not ID code verification is established.
If ID code verification is not established, the process proceeds to step S06, and if established, the process proceeds to step S07.

<Step S06: Increase antenna output and form collation communication area>
The verification control unit 10 increases the antenna output by a predetermined value to form a verification communication area.
Then, it returns to step S05 and repeats subsequent processes.

<Step S07: Increase antenna output and form collation communication area>
The verification control unit 10 reduces the antenna output by a predetermined value to form a verification communication area.
Then, it returns to step S05 and repeats subsequent processes.
Here, the amount of change (change width) of the antenna output in steps S06 and S07 is set to be relatively large at the beginning of the trial, and it is possible to specify a range in which the collation can be made early or impossible.
As the number of trials increases, the amount of change in antenna output is reduced, and the minimum antenna output that can be verified can be detected with good resolution.
Specifically, the amount of change may be sequentially reduced, for example, from the maximum output to the output 1/2, and the subsequent output change amount to 1/4, 1/8,... Of the maximum output.
After the trial of steps S05 to S07 is completed for a predetermined number of times, the process proceeds to step S08.

<Step S08: Determination of antenna output>
The collation control unit 10 determines the minimum antenna output (minimum antenna output at which the electronic key 100 can receive radio waves from the transmission antenna) for which collation is established.
The above-described processing of steps S01 to S08 is performed for each of the transmission antennas 21 to 23, and after completion, the process proceeds to step S09.

<Step S09: Key position estimation>
The verification control unit 10 queries the output-verification range database 11 for the antenna output determined in step S08, and acquires information about the outer edge of the verification range (receivable range by the electronic key 100) in this antenna output. .
And the area | region where the outer edge of each collation possible range of each transmission antenna 21-23 crosses is estimated as a place where the electronic key 100 exists.
Then, it progresses to step S10.

<Step S10: Implementation of control based on user operation>
The collation control unit 10 performs the control specified by the user operation using the position of the electronic key 100 estimated in step S09.
For example, when the user's request is to display the position of the electronic key 100, the estimated position of the electronic key 100 is displayed on the display device 50.
Thereafter, the series of processing is terminated.

According to the embodiment described above, the electronic key 100 can receive the radio waves transmitted by the transmitting antennas 21 to 23, and the minimum antenna output at which communication between the vehicle side and the electronic key 100 is established is detected. The range within which the electronic key 100 exists with respect to each of the transmission antennas 21 to 23 is estimated, and the overlapping range is detected as the position of the electronic key 100. It is possible to accurately detect the position of the head.
In addition, the detection accuracy can be further improved by preliminarily storing the relationship between the output of each transmission antenna 21 to 23 and the collable range as data reflecting the influence of a component having a property of shielding radio waves. .
Furthermore, convenience can be improved by displaying a detection result on the display device 50 and notifying the user.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
For example, the configuration of the position detection device, the number of antennas, and the arrangement are not limited to the above-described embodiments, and can be changed as appropriate. In this case, at least three transmission antennas may be arranged so as not to be aligned. Further, the method of changing the antenna output is not particularly limited.
Further, the vehicle to be applied is not limited to the two-row seat passenger car as in the embodiment, and can be appropriately changed.
Furthermore, the control performed using the detected position is not limited to the display on the display device as in the embodiment.

DESCRIPTION OF SYMBOLS 1 Position detection apparatus 10 Collation control unit 11 Output-collation possible range database 21 Right front transmission antenna 22 Left front transmission antenna 23 Rear transmission antenna 24 Vehicle reception antenna 30 Engine control unit 40 Car body integration unit 41 Door lock actuator 50 Display device 60 Key Search operation unit 100 Electronic key A1 to A3 Range that can be verified

Claims (5)

An electronic key position detection device that detects the position of an electronic key that is portable by a user and communicates with an onboard unit mounted on a vehicle to perform ID code verification,
A first transmission antenna provided on a vehicle for transmitting radio waves received by the electronic key;
A second transmission antenna provided at a position away from the first transmission antenna of the vehicle;
A third transmission antenna provided at a position separated from a straight line connecting the first transmission antenna and the second transmission antenna of the vehicle;
A receiving antenna provided in a vehicle for receiving radio waves transmitted by the electronic key;
Transmission to the electronic key is sequentially performed for each antenna while changing the outputs of the first to third antennas, and the electronic key can receive radio waves transmitted by the first to third antennas. An electronic key position detecting device comprising: position determining means for determining a position of the electronic key with respect to the vehicle body based on a minimum output. The position determination means estimates a distance from each transmission antenna to the electronic key according to a minimum output at which the electronic key can receive radio waves transmitted from the first to third transmission antennas, respectively. The position of the electronic key is determined. The electronic key position detection device according to claim 1. The position determination means holds information about the receivable range of the electronic key according to the outputs of the first to third transmission antennas, and the electronic key receives radio waves transmitted by the first to third antennas. The electronic key position detecting device according to claim 1, wherein a region where an outer edge of a receivable range corresponding to a minimum output that can be overlapped is determined as the position of the electronic key. The position determination means reduces an output change amount when sequentially changing the outputs of the first to third transmission antennas as the number of times the output change is performed increases. The electronic key position detecting device according to any one of claims 1 to 3. The electronic key position detection device according to any one of claims 1 to 4, further comprising notification means for notifying a user of the position of the electronic key determined by the position determination means.

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