JP2012107377A - Portable unit search device and portable unit search method for vehicular smart key - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure detection of existence of a portable unit and identification of a position of the portable unit using a small number of antennas.SOLUTION: A first transmission antenna 16 (LF antenna 3) is attached to a pillar 15 at a driver side of a vehicle, and a second transmission antenna 18 (LF antenna 3) is attached to a pillar 17 at a front passenger-seat side. Radio waves each with intensities of L1 and L3 are transmitted from the first transmission antenna 16 and the second transmission antenna 18 so that the respective intensities L1 and L3 are increased stepwise, and existence of a portable unit 1 in the vehicle is detected. A position of the portable unit 1 is identified based on boundary values of the intensities L1 and L3 of the respective radio waves received by the portable unit 1.

Description

  The present invention detects the presence or absence of the portable device in a vehicle smart key system (registered trademark) that locks / unlocks at least the door of the vehicle by radio waves transmitted and received between the portable device and the vehicle, In addition, the present invention relates to a portable device search apparatus and a portable device search method for specifying the position.

  In recent vehicles (for example, automobiles), radio waves are transmitted and received between an electronic key (portable device) owned by the user and a control device mounted on the vehicle. Devices that perform locking / unlocking are widespread (see, for example, Patent Document 1). Of these types of devices, the user who holds the portable device touches the door, and the door is locked / unlocked automatically. When starting the engine, the portable device is held and the engine switch is operated. All that needs to be done (in other words, it is not necessary to insert a key into the ignition key hole and turn it) is called a “smart key system”.

  In the vehicle smart key system, in order to set the vehicle door to the lock / unlock standby state or to set the engine to the start standby state, the antenna mounted on the vehicle detects the portable device, and the control means detects the ID. You need to authenticate your code. In many cases, the user places the portable device in a pocket of clothes or stores it in a bag. For this reason, the vehicle equipped with the smart key system is provided with radio wave transmission means (antenna) to detect the presence or absence of the portable device (that is, the position of the portable device inside or outside the vehicle).

  In order to detect the presence / absence (position) of a portable device with certainty, it is necessary to narrow the transmission area of radio waves and attach a large number of antennas. In this case, a large number of antennas sequentially transmit radio waves to search for a portable device. For this reason, it takes a long time to specify the position of the portable device (poor responsiveness). In addition, the cost increases because of the large number of antennas.

  If the number of antennas is reduced and the output intensity is increased to widen the transmission area for radio waves (communication request radio waves), the control means will determine that the portable device is in the car, even though it is outside the car. There is a risk that. In this case, a user in the vehicle may start the engine without having a portable device.

  Further, if the output range (transmission area) is increased by increasing the intensity of the radio wave, the radio wave output from the antenna may adversely affect other in-vehicle electronic devices.

JP 2008-72210 A

  In view of the above-described problems, the present invention provides a portable device searching device and a portable device searching method for a smart key system for a vehicle that can reliably detect the presence / absence of a portable device and specify its position with a small number of antennas. The issue is to provide.

The first invention for solving the above-described problems is
In the vehicle smart key system that locks / unlocks at least the door of the vehicle by radio waves transmitted / received between the portable device and the vehicle, for detecting the presence / absence of the portable device and specifying the position thereof A portable device search device,
A plurality of radio wave transmitting means attached to different positions of the vehicle and transmitting communication request radio waves of a predetermined intensity in a predetermined order;
Radio wave receiving means for receiving a response radio wave transmitted when the portable device receives a communication request radio wave from the radio wave transmitting means;
In order to obtain a boundary value when the portable device receives a communication request radio wave from the radio wave transmission means and transmits a response radio wave, the output intensity of the communication request radio waves transmitted by the plurality of radio wave transmission means is adjusted. Radio wave intensity adjusting means to
Portable device presence / absence detecting means for detecting the presence / absence of the portable device based on whether the communication request radio waves are received from the plurality of radio wave transmitting means;
When the portable device presence / absence detecting means detects the presence of the portable device within the transmission area of the radio wave transmitted by the radio wave transmitting means, the radio wave intensity adjusting means adjusts the plurality of radio wave transmitting means. Portable device position specifying means for specifying the position of the portable device by determining which intensity of the transmitted radio wave is received by the portable device;
It is characterized by providing.

  In the first invention, the strength of the communication request radio wave transmitted by the plurality of radio wave transmission means is adjusted by the radio wave intensity adjustment means. The portable device that has received this radio wave transmits a response radio wave, which is received by the radio wave receiving means. Depending on whether the portable device has received radio waves, the portable device presence / absence detecting means detects the presence or absence of the portable device. Furthermore, the position of the portable device is specified based on the boundary value of the intensity of the radio wave when the portable device receives. Thus, in the portable device search device according to the present invention, the boundary value of the radio wave received by the portable device is determined by adjusting the strength of the radio wave transmitted by the radio wave transmitting means. As a result, even if the number of radio wave transmission means is small (two or more are sufficient), the presence / absence of the portable device is detected and the position thereof is specified. Since the number of radio wave transmission means is small, the time required for searching for a portable device can be shortened.

  And even when the plurality of radio wave transmitting means transmit communication request radio waves with the maximum intensity, when the radio wave receiving means does not receive a response radio wave from the portable machine, the portable machine presence / absence detecting means Determines that the portable device does not exist within the transmission area of the radio wave transmission means (that is, exists outside the detection area).

The plurality of radio wave transmission means include at least first and second radio wave transmission means,
The second radio wave transmission means transmits the second communication request radio wave after the portable device that has received the first communication request radio wave transmitted from the first radio wave transmission means transmits the first response radio wave, The second response radio wave transmitted by the portable device that has received the second communication request radio wave is received.

  In this way, the presence or absence of the portable device is detected by transmitting a plurality of radio wave transmission means in order, and the portable device is detected from the boundary value of the radio wave received by the portable device (ie, the overlapping area of the radio wave transmission areas). Locate the machine.

  The first radio wave transmission means is attached to the driver seat side in the vehicle width direction, and the second radio wave transmission means is attached to the passenger seat side in the vehicle width direction.

  Thereby, the position of the portable device in the width direction of the vehicle can be specified. And in order to pinpoint a position more finely, a 3rd electromagnetic wave transmission means can be attached to the center part of the width direction of the said vehicle. Furthermore, by moving the position of the third radio wave transmission means in the front-rear direction, the position of the portable device can be specified not only in the width direction but also in the front-rear direction.

The second invention for solving the above-described problems is as follows.
In the vehicle smart key system that locks / unlocks at least the door of the vehicle by radio waves transmitted / received between the portable device and the vehicle, for detecting the presence / absence of the portable device and specifying the position thereof A mobile device search method,
A radio wave transmitting step in which a plurality of radio wave transmitting means attached to different positions of the vehicle transmit communication request radio waves of a predetermined intensity in a predetermined order;
A radio wave receiving step in which the radio wave receiving means receives a response radio wave transmitted by the portable device with respect to a communication request radio wave transmitted by the radio wave transmitting means;
Radio wave intensity adjustment step of adjusting the magnitude of the output intensity of the radio waves transmitted by the plurality of radio wave transmission means in order to obtain a boundary value indicating which radio wave the radio wave transmission means receives by the portable device When,
A portable device presence / absence detection step of detecting the presence / absence based on whether the portable device has received communication request radio waves from the plurality of radio wave transmission means;
A portable device position that identifies the position of the portable device by determining which strength of the radio wave is transmitted from the plurality of radio wave transmitting means when the presence of the portable device is detected. Specific process,
It is characterized by including.

  In the second invention, the first invention is regarded as a method invention, and the same effects as the first invention can be obtained.

It is a block diagram which shows schematic structure of the portable device search apparatus 101 of 1st Example. It is a top view of the vehicle 2 with which the portable device search apparatus 101 was mounted. 5 is a flowchart showing the operation of the portable device searching apparatus 101. It is operation | movement explanatory drawing when the 1st transmission antenna 16 searches the portable device 1 in a vehicle. It is operation | movement explanatory drawing when the 2nd transmission antenna 18 searches the portable device 1 in a vehicle. It is operation | movement explanatory drawing when the 1st transmission antenna 16 searches the portable device 1 outside a vehicle. It is operation | movement explanatory drawing when the 1st thru | or 3rd transmission antenna 16,18,27 searches the portable device 1 in a vehicle. It is a flowchart which shows another search method.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a block diagram showing a schematic configuration of a portable device search device 101 according to the first embodiment, FIG. 2 is a plan view of a vehicle 2 on which the portable device search device 101 is mounted, and FIG. It is a flowchart to show.

  As shown in FIG. 1, the portable device searching apparatus 101 according to the first embodiment includes a portable device 1 carried by a user and a vehicle mounting unit 200 mounted on the vehicle 2. The portable device 1 records a unique ID code for each vehicle and performs wireless communication with the vehicle 2 (see FIG. 2). Specifically, the vehicle mounting unit 200 collates with an ID code whether or not a portable device for the vehicle exists within a predetermined distance range from the vehicle 2, and performs predetermined function control (for example, based on the collation result) , To prepare for starting the engine, etc., in a door lock / unlock standby state. On the other hand, the vehicle mounting unit 200 includes an LF transmitter 4 to which an LF antenna 3 (radio wave transmitting means) is connected and an RF receiver 6 (also referred to as a tuner) to which an RF antenna 5 (radio wave receiving means) is connected. Each of which is connected to the ECU 7.

  The LF transmitter 4 modulates the LF carrier signal with a baseband signal reflecting the portable key ID and the like, and periodically and repeatedly transmits it as a polling radio wave (communication request radio wave, also called a request signal). For this reason, hereinafter, the LF antenna 3 may be referred to as a “transmission antenna”. If the portable device 1 exists in the polling radio wave transmission area, the portable device 1 receives this polling radio wave, demodulates the baseband signal, and analyzes the contents. As a result of the analysis, if it is confirmed that the polling is performed, the portable device 1 transmits an RF response radio wave (response radio wave, also referred to as an answer signal) reflecting the authentication ID to the vehicle side. On the vehicle side, this is received by the RF receiver 6 via the RF antenna 5, and the baseband signal including the authentication ID is demodulated. The ECU 7 compares the authentication ID included in the demodulated baseband signal with the master ID stored in the non-volatile memory 8 and performs authentication processing, and only when the result is authentication acceptance, the door lock device 9 is controlled. For example, when the user holding the portable device 1 approaches the vehicle and receives authentication in response to the above-described polling, the vehicle-side mounting unit 200 receives input from the touch sensor 11 provided on the door knob (not shown). Activate. When the touch sensor 11 detects that the user's finger has touched, the door lock device 9 performs a lock / unlock operation.

  The ECU 7 includes a radio wave intensity adjusting unit 12 that adjusts the output intensity of the radio wave transmitted from the LF antenna 3, a portable device presence / absence detecting unit 13 that determines whether the portable device 1 is present, and a portable device that specifies the position of the portable device 1. The machine position specifying means 14 is connected. These functions will be described later.

  As shown in FIG. 2, a first transmission antenna 16 (LF antenna 3) is attached to a pillar 15 (B pillar) on the driver's seat side of the vehicle 2. A second transmission antenna 18 is attached to the pillar 17 on the passenger seat side of the vehicle 2. The first transmission antenna 16 detects the presence or absence of the portable device 1 around the driver's seat 19 in the vehicle, around the driver's seat on the rear seat 21 and around the front and rear doors 22 and 23 on the driver's seat outside the vehicle. The second transmission antenna 18 detects the presence or absence of the portable device 1 around the passenger seat 24 in the vehicle, around the passenger seat side of the rear seat 21, and around the front and rear doors 25, 26 outside the vehicle. is there. The first and second transmitting antennas 16 and 18 output radio waves having a predetermined intensity. The radio waves output from the first and second transmission antennas 16 and 18 have no directivity, and are output concentrically around the transmission antennas 16 and 18 (see FIG. 4). The higher the radio wave output intensity, the longer the radio wave reach distance (that is, the radio wave transmission area becomes wider). The intensity of the radio waves output from the first and second transmission antennas 16 and 18 can be changed by the radio wave intensity adjusting means 12. The maximum transmission areas of the first and second transmission antennas 16 and 18 are assumed to be inside the vehicle 2.

  The operation when the portable device searching apparatus 101 according to the present embodiment detects the presence or absence of the portable device 1 and specifies the position thereof will be described with reference to the flowchart of FIG. As shown in FIG. 4, it is assumed that the portable device 1 is placed in the passenger seat 24.

  As shown in FIG. 4A, first, the first transmitting antenna 16 transmits a radio wave (communication request radio wave, also referred to as a request signal) having a predetermined intensity L1 (step S10). If portable device 1 is present in the transmission area of the transmitted radio wave (“Yes” in step S20), portable device 1 responds and transmits a response radio wave (also referred to as an answer signal) (step S30). . However, in the case shown in FIG. 4A, the portable device 1 does not respond because the portable device 1 does not exist within the radio wave transmission area of the first transmission antenna 16 (“No” in step S20). Then, the radio wave intensity adjusting unit 12 increases the intensity L1 of the radio wave transmitted from the first transmitting antenna 16 (step S40). The intensity of the radio wave at this time is L2 (L2> L1).

  As shown in FIG. 4B, when the portable device 1 is within the transmission area of the radio wave of intensity L2 transmitted from the first transmission antenna 16, a response radio wave is transmitted from the portable device 1 (step S30). ). When the RF receiver 6 receives this via the receiving antenna (RF antenna 5), the portable device presence / absence detecting means 13 detects that the portable device 1 is present in the radio wave transmission area from the first transmitting antenna 16. (That is, it is determined that the portable device 1 exists in the transmission area). The intensity L2 of the radio wave transmitted by the first transmitting antenna 16 and detecting the presence of the portable device 1 is stored in the memory 8 of the ECU 7. In this state, the presence of the portable device 1 is detected within the transmission area of the radio wave having the intensity L2 transmitted by the first transmitting antenna 16, but the position of the portable device 1 is specified (for example, in the vehicle). Or is it outside the car) is difficult.

  Next, as shown in FIG. 5A, the second transmission antenna 18 transmits a radio wave (request signal) having a predetermined intensity L3 (step S50). As in the case of the first transmitting antenna 16, if the portable device 1 exists in the transmission area of the radio wave (intensity L3) transmitted at this time ("Yes" in step S60), the portable device 1 responds, A response radio wave (answer signal) is transmitted (step S70). However, when it is detected that the portable device 1 does not exist in the radio wave transmission area, the radio wave intensity adjusting unit 12 increases the intensity L3 of the radio wave transmitted from the second transmission antenna 18 (step S80). The intensity of the radio wave at this time is L4 (L4> L3).

  As shown in FIG. 5B, when the portable device 1 is present in the transmission area of the radio wave of intensity L4 transmitted from the second transmission antenna 18, a response radio wave is transmitted from the portable device 1 (step S70). ). When the RF receiver 6 receives this via the receiving antenna (RF antenna 5), the portable device presence / absence detecting means 13 determines that the portable device 1 exists in the radio wave transmission area from the second transmitting antenna 18. The intensity L4 of the radio wave at this time is stored in the memory 8 of the ECU 7.

  When it is confirmed that the portable device 1 exists in the transmission area of each radio wave transmitted from the first and second transmission antennas 16 and 18, the portable device position specifying means 14 is stored in the memory 8. The position of the portable device 1 is specified based on the strength L2, L4 of each radio wave (that is, the boundary value of the strength of the radio wave received by the portable device 1) (step S90). The position of the portable device 1 is specified by an overlapping portion of transmission areas of radio waves transmitted from the first and second transmission antennas 16 and 18. In the case of FIGS. 4 and 5, the transmission area of the first transmission antenna 16 is larger than the transmission area of the second transmission antenna 18, so that the portable device 1 is closer to the passenger seat than the center in the width direction of the vehicle 2. Specified to exist.

  When the presence of the portable device 1 is detected by the above-described action, the ECU 7 executes smart key processing (step S100). Smart key processing means, for example, setting the engine in a start standby state, starting the engine by a user operation, or setting the door in a lock / unlock standby state.

  Next, as shown in FIG. 6, a case where a user (not shown) carrying the portable device 1 approaches the front door 22 on the driver's seat side of the vehicle 2 will be described. At this time, when the portable device 1 enters the transmission area of the radio wave transmitted by the first transmission antenna 16, a response radio wave is transmitted from the portable device 1. Subsequently, a radio wave is transmitted from the second transmission antenna 18. However, since the position of the portable device 1 is outside the driver's seat 19 side of the vehicle 2, it is outside the transmission area of the radio wave transmitted by the second transmission antenna 18. In this case, if the presence of the portable device 1 is detected only by the first transmission antenna 16 and the presence of the portable device 1 is not detected by the second transmission antenna 18, the position of the portable device 1 is the driving of the vehicle 2. It is specified that it is outside the seat 19 side.

  In the portable device searching apparatus 101 of the first embodiment, the radio wave intensity adjusting means 12 adjusts the intensity L1 and L3 of each radio wave transmitted from the two transmitting antennas 16 and 18. Thereby, the boundary value of the intensity | strength L1, L3 of the electromagnetic wave which the portable device 1 receives can be acquired easily. And the position of the portable device 1 is specified from these boundary values. In other words, since the number of transmission antennas 16 and 18 necessary for specifying the position of the portable device 1 is two, the response is good and the time until the position is specified can be shortened. In other words, even if the number of transmission antennas 16 and 18 is small, the position of the portable device 1 can be specified in a short time.

  The portable device searching apparatus 101 according to the first embodiment detects the presence / absence of the portable device 1 and identifies its position by the two transmission antennas 16 and 18 installed on both sides in the width direction of the vehicle 2. . In the case of the search device 101 of this embodiment, it is possible to specify the position of the portable device 1 in the width direction of the vehicle 2, but it is difficult to specify the position of the portable device 1 in the front-rear direction of the vehicle 2. . In the portable device searching apparatus 102 of the second embodiment, a third transmission antenna 27 is attached to the rear portion of the vehicle 2 in order to specify the position of the portable device 1 with higher accuracy. Then, radio waves of a predetermined intensity are transmitted in order from the first to third transmission antennas 16, 18, and 27, and the portable device 1 that has received the radio waves transmits a response radio wave. The position of the machine 1 is specified as an overlapping portion of the transmission areas of the radio waves from the first to third transmission antennas 16, 18, and 27. In the case shown in FIG. 7, it is determined that the portable device 1 exists in the front part on the passenger seat 24 side.

  Next, another search method for specifying the position of the portable device 1 will be described. In the first search method described above, the first transmitting antenna 16 first transmits a radio wave having an intensity L1, and when the portable device 1 is not detected, the intensity L1 is increased stepwise. However, when the first transmitting antenna 16 first transmits a radio wave having the maximum intensity and the portable device 1 is detected within the transmission area, the radio wave intensity may be gradually reduced. At this time, for example, the intensity of the radio wave transmitted by the first transmitting antenna 16 for the second time is made half of the maximum intensity, and the intensity of the radio wave transmitted for the third time is made half the intensity of the second time (1/4 of the maximum intensity). In this way, the method of narrowing down the intensity by half may be used.

  That is, as shown in the flowchart of FIG. 8, the first transmitting antenna 16 transmits a radio wave having the maximum intensity (step S10). If the portable device 1 exists in the transmission area (“Yes” in step S20), the radio wave intensity is halved (step S30). If the portable device 1 does not exist in the transmission area (“No” in step S20), it is determined that the portable device 1 does not exist on the driver's seat 19 side (step S40). Further, the radio wave is transmitted at the intensity, and the process continues until the portable device 1 is not detected in the transmission area at that time (“No” in step S50), and the radio wave intensity at that time is stored (step S60). The operation of the second (or lower) transmission antenna 18 is exactly the same as described above.

In the case of this method, if it is assumed that the portable device 1 exists in the vehicle, the presence or absence of the portable device 1 is always detected by transmission of the first radio wave (maximum intensity). And since the degree which reduces the intensity | strength of an electromagnetic wave is large in order to obtain | require the boundary value of the intensity | strength of the electromagnetic wave which the portable device 1 responds, the presence or absence of the portable device 1 can be detected more rapidly.

  Moreover, when the user who exists in the exterior of the vehicle 2 has the portable device 1, the position of the portable device 1 once identified may change as the user moves. At this time, when the transmission antenna detects the portable device 1 again, the transmission antenna may start by transmitting a radio wave having an intensity that is one step larger than the radio wave intensity when the position is specified. This is because even if the user moves or moves away from the vehicle 2 from the position at which the portable device 1 was first identified, the movement may be within the transmission area accompanying a one-step change in the radio field intensity. Always responds by the transmission of the first radio wave. For this reason, the presence / absence of the portable device 1 is detected more quickly than in the case where the intensity of the radio wave is increased stepwise.

  The user may be notified of the position of the portable device 1 specified by the above-described operation using a notification unit. In this case, since the user always recognizes the position of the portable device 1, the user gets off with the portable device 1 placed in the vehicle, and the problem that the door cannot be locked is less likely to occur. As the notification means, it is conceivable to display such information on a display of a navigation device (not shown) or to notify by voice.

  In this specification, the portable device search device and the portable device search method in the smart key system for a vehicle have been described. However, it can also be implemented in a vehicle PKE system (Passive Keyless Entry system).

  The present invention can be used as a portable device search device or a portable device search method in a smart key system in a vehicle.

101, 102 portable device search device 1 portable device 2 vehicle 3 LF antenna (radio wave transmission means)
4 RF antenna (radio wave receiving means)
12 radio wave intensity adjusting means 13 portable device presence / absence detecting means 14 portable device position specifying means 16 first transmitting antenna (radio wave transmitting means)
18 Second transmitting antenna (radio wave transmitting means)
27 Third transmitting antenna (radio wave transmitting means)

Claims (6)

In the vehicle smart key system that locks / unlocks at least the door of the vehicle by radio waves transmitted / received between the portable device and the vehicle, for detecting the presence / absence of the portable device and specifying the position thereof A portable device search device,
A plurality of radio wave transmitting means attached to different positions of the vehicle and transmitting communication request radio waves of a predetermined intensity in a predetermined order;
Radio wave receiving means for receiving a response radio wave transmitted when the portable device receives a communication request radio wave from the radio wave transmitting means;
In order to obtain a boundary value when the portable device receives a communication request radio wave from the radio wave transmission means and transmits a response radio wave, the output intensity of the communication request radio waves transmitted by the plurality of radio wave transmission means is adjusted. Radio wave intensity adjusting means to
Portable device presence / absence detecting means for detecting the presence / absence of the portable device based on whether the communication request radio waves are received from the plurality of radio wave transmitting means;
When the portable device presence / absence detecting means detects the presence of the portable device within the transmission area of the radio wave transmitted by the radio wave transmitting means, the radio wave intensity adjusting means adjusts the plurality of radio wave transmitting means. Portable device position specifying means for specifying the position of the portable device by determining which intensity of the transmitted radio wave is received by the portable device;
A portable device search device for a smart key system for vehicles.   Even when the plurality of radio wave transmitting means transmit a communication request radio wave with the maximum strength, when the radio wave receiving means does not receive a response radio wave from the portable device, the portable device presence / absence detecting means is: 2. The portable device searching device for a smart key system for a vehicle according to claim 1, wherein the portable device is determined not to exist within a transmission area of the radio wave transmitting means. The plurality of radio wave transmission means include at least first and second radio wave transmission means,
The second radio wave transmission means transmits the second communication request radio wave after the portable device that has received the first communication request radio wave transmitted from the first radio wave transmission means transmits the first response radio wave, The mobile device search device for a smart key system for a vehicle according to claim 1 or 2, wherein the mobile device receives the second response radio wave transmitted by the mobile device that has received the second communication request radio wave.   The first radio wave transmission means is attached to a driver's seat side in the vehicle width direction, and the second radio wave transmission means is attached to a passenger seat side in the vehicle width direction. 4. A portable device searching device for a smart key system for a vehicle according to 3.   5. The portable device searching device for a smart key system for a vehicle according to claim 4, wherein a third radio wave transmitting means is attached to a central portion in the width direction of the vehicle. In the vehicle smart key system that locks / unlocks at least the door of the vehicle by radio waves transmitted / received between the portable device and the vehicle, for detecting the presence / absence of the portable device and specifying the position thereof A mobile device search method,
A radio wave transmitting step in which a plurality of radio wave transmitting means attached to different positions of the vehicle transmit communication request radio waves of a predetermined intensity in a predetermined order;
A radio wave receiving step in which the radio wave receiving means receives a response radio wave transmitted by the portable device with respect to a communication request radio wave transmitted by the radio wave transmitting means;
Radio wave intensity adjustment step of adjusting the magnitude of the output intensity of the radio waves transmitted by the plurality of radio wave transmission means in order to obtain a boundary value indicating which radio wave the radio wave transmission means receives by the portable device When,
A portable device presence / absence detection step of detecting the presence / absence based on whether the portable device has received communication request radio waves from the plurality of radio wave transmission means;
A portable device position that identifies the position of the portable device by determining which strength of the radio wave is transmitted from the plurality of radio wave transmitting means when the presence of the portable device is detected. Specific process,
A portable device search method for a smart key system for a vehicle, comprising:

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