JP2015113643A - Keyless entry system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a keyless entry system capable of accurately determining whether a portable machine is in a cabin without any increase in cost by composing a transmission antenna of two antennas.SOLUTION: A vehicle-side transmission antenna 2 comprises only two antennas which are a first transmission antenna 2a and a second transmission antenna 2b provided at predetermined positions. A vehicle-side reception part 3 or portable machine-side reception part 13 has a circuit (3a or 13a) which detects signal intensity of an answer signal or request signal, and a vehicle-side control part 5 or portable machine-side control part 15 calculates a first distance as the distance between a portable machine 20 and the first transmission antenna 2a and a second distance as the distance between the portable machine 20 and second transmission antenna 2b based upon the signal intensity, and compares the first distance and second distance, and a third distance as the total of the first distance and second distance with predetermined thresholds respectively so as to determine whether the portable machine 20 is in a cabin.

Description

  The present invention relates to a keyless entry system that locks or unlocks a door of a vehicle and starts an engine by performing wireless communication between the in-vehicle device and the portable device, and particularly, automatically between the in-vehicle device and the portable device. The present invention relates to a passive keyless entry system having a function for communication.

  In moving vehicles such as automobiles, when the automobile is not in use, the door of the automobile door is locked to prevent the automobile from being stolen or being intruded into the automobile and damaging the internal devices. Provided. Conventionally, the door lock is locked or unlocked by inserting a key for starting the engine into the key hole. However, for convenience, the key of the portable device is not inserted without inserting the key into the key hole. A so-called keyless entry system that unlocks and locks a door lock by operating a switch is used. Further, in recent years, a so-called passive device that unlocks and locks a door lock can be achieved by holding a predetermined portable device and operating a vehicle door switch located in a predetermined region without operating the portable device switch. A keyless entry system is used. Furthermore, the passive keyless entry system has an electrical authentication function for starting the engine, and the safety is improved by preventing the engine from starting unless authentication is established between the car body and the portable device. is there.

  The operation of the keyless entry system is a low-frequency signal including a wake-up signal from a vehicle-mounted device when a person holding a portable device already registered in the vehicle-mounted device mounted on the vehicle approaches the vehicle. Send a request signal. When the portable device receives the request signal, the portable device responds and transmits an answer signal that is a high-frequency signal including a command signal. When the on-vehicle device receives the answer signal, the on-vehicle device is included in the answer signal. The controlled device is controlled according to the command signal. The control is, for example, unlocking the door of the automobile or starting the engine of the automobile, so that the driver can drive the automobile.

  The keyless entry system in which such a series of operations is performed includes a function that contributes to starting the engine when the portable device is inside the vehicle compartment, and locking the door lock when the portable device is outside the vehicle compartment. Some have functions that contribute to unlocking. In addition, in order to prevent misplacement of the portable device in the vehicle interior, there is a device having a function of preventing the door from being locked when the portable device is in the vehicle interior.

  In such a keyless entry system, it is important to detect with high accuracy whether the portable device is inside or outside the vehicle. As a keyless entry system for performing detection and determination, there is known a system in which a plurality of antennas for transmitting request signals are arranged in a vehicle interior or in a vehicle interior and a vehicle interior, respectively. According to this type of keyless entry system, since the request signal is transmitted from the in-vehicle device via the plurality of antennas, if the portable device is in a predetermined range outside the vehicle interior or outside the vehicle interior, Thus, it is possible to reliably transmit and receive radio signals between the in-vehicle device and the portable device. Accordingly, it can be accurately determined whether the portable device is in the vehicle interior or the vehicle interior.

  In any of these keyless entry systems, when a legitimate request signal is transmitted via two or more antennas, the portable device that has received one of the request signals responds with an answer signal. Send. Then, the place where the portable device is located is determined based on the fact that the in-vehicle device receives an answer signal from the portable device.

  For example, the in-vehicle device remote control system described in Patent Document 1 discloses a configuration that can reduce the cost without impairing security and convenience and using only two transmission antennas. An in-vehicle device remote control system 900 described in Patent Literature 1 is shown in FIG.

The encryption code request signal is alternately transmitted from the antenna 906 and the antenna 907 which are encryption code request signal transmission antennas disposed on the left and right doors. As a result, if a return code can be received from the portable wireless device 950 for any transmission,
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This means that the mobile wireless device 950 exists in an area where both the downward slanted line area 910 and the upward right slanted line area 911 overlap, and this area coincides with the area in the vehicle.

  By this method, it is possible to determine whether or not the portable wireless device 950 exists in the vehicle interior, and the position of the portable wireless device 950 can be determined. Therefore, while it is determined that the portable wireless device 950 is in the passenger compartment, if the driver of the vehicle goes out of the passenger compartment without holding the portable wireless device 950 and tries to lock the door, the door cannot be locked. Alarms such as sounding horns can be generated. In other words, it is possible to call attention for preventing the portable wireless device 950 from being misplaced and improve the security performance. In addition, since only two antennas, the right door antenna 906 and the left door antenna 907, are used as transmitting antennas, compared to the case where three or more antennas are required, the cost of parts and the number of man-hours can be reduced. It can be reduced.

1386206662504_1 Publication

  However, the in-vehicle device remote control system 900 described in Patent Document 1 has the following problems. An area 910 within the encryption code request signal transmission area by the antenna 906 in the vicinity of the right door (a right-down hatching area in FIG. 7) and an area 911 within the encryption code request signal transmission area by the antenna 907 in the vicinity of the left door (at the right in FIG. 7) Each rising hatch area is represented by a circular shape centered on the antenna installation position. Therefore, a region where the region 910 and the region 911 overlap (hereinafter referred to as an overlapping region) has a shape in which the tip protrudes in the front-rear direction of the vehicle, that is, a rugby ball shape in plan view (shown by a broken line in FIG. 7). As a result, if it is determined that the overlapping region is in the passenger compartment, it may be determined that the portable wireless device 950 is outside the passenger compartment at the four corners of the actual passenger compartment, even though the portable wireless device 950 is in the passenger compartment. It was. Further, in order to solve this problem, when the overlapping area is widened, the overlapping area having a rugby ball shape in plan view protrudes from the shape of the passenger compartment having a substantially rectangular shape in plan view. . For this reason, there is a possibility that the portable wireless device 950 may be determined to be in the passenger compartment even though the portable wireless device 950 is outside the vehicle.

  Of course, if the position of the portable wireless device 950 can be accurately determined with respect to the front-rear and left-right directions of the passenger compartment, it can be accurately determined whether the portable wireless device 950 is inside or outside the passenger compartment. However, in order to accurately determine the position of the portable wireless device 950 in this way, only two transmission antennas are needed. For example, if the determination is made using the trigonometric method, the position of the portable wireless device 950 can be accurately determined. To that end, at least three transmission antennas are required. However, increasing the number of transmit antennas results in increased costs associated with the keyless entry system.

  The present invention has been made in view of such a technical background, and an object of the present invention is to provide a portable device in a vehicle interior without increasing costs by configuring the transmission antenna with only two transmission antennas. An object is to provide a keyless entry system that can accurately determine whether the vehicle is outside the vehicle compartment.

  In order to solve this problem, a keyless entry system of the present invention is a keyless entry system including an in-vehicle device provided in a vehicle and a portable device possessed by a user, and the in-vehicle device is included in the portable device. A vehicle-side transmission unit that transmits a request signal; a vehicle-side transmission antenna connected to the vehicle-side transmission unit; a vehicle-side reception unit that receives an answer signal from the portable device; A vehicle-side control unit that controls the mobile device, the portable device receiving a request signal from the vehicle-side transmission antenna, and a portable device-side transmission unit transmitting the answer signal. A vehicle-side control unit that performs predetermined control, and the vehicle-side transmission antenna includes two transmission antennas, a first transmission antenna and a second transmission antenna, provided at predetermined positions. The vehicle-side receiver or the portable device-side receiver has a circuit that detects the signal strength of the answer signal or the request signal, and the vehicle-side controller or the portable device-side controller is A first distance that is a distance between the portable device and the first transmission antenna and a second distance that is a distance between the portable device and the second transmission antenna are based on the signal strength. By calculating and comparing the first distance, the second distance, and the third distance, which is the total distance of the first distance and the second distance, respectively with a predetermined threshold, It has the characteristic of determining whether the vehicle is inside or outside the vehicle.

  The keyless entry system configured as described above includes a first distance that is a distance between the portable device and the first transmitting antenna, a second distance that is a distance between the portable device and the second transmitting antenna, Since the third distance, which is the total distance of the first distance and the second distance, is used for the determination, the two transmission antennas are used even though only two transmission antennas are configured. No new information is required other than the first distance and the second distance obtained in (1). Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

In the above configuration, the portable device has a radius of a first signal arrival distance in which a signal intensity transmitted from the first transmission antenna is a predetermined value or more with the installation position of the first transmission antenna as a central point. Inside the first circle, and
The second transmission antenna is located inside a second circle having a radius that is a second signal arrival distance in which a signal intensity transmitted from the second transmission antenna is a predetermined value or more with the installation position of the second transmission antenna as a center point; and
The installation position of the first transmission antenna and the installation position of the second transmission antenna are used as focal points, respectively, and the third signal arrival distance, which is the total distance of the first signal arrival distance and the second signal arrival distance, is used. When inside the ellipse
It is characterized in that it is determined that the portable device is in the vehicle interior.

  The keyless entry system configured as described above is a condition for determining whether the portable device is inside or outside the ellipse that has the installation position of the first transmission antenna and the installation position of the second transmission antenna as the focal points. By adding to the above, it is possible to remove the area outside the passenger compartment in the longitudinal direction of the vehicle from the area where the first circle and the second circle overlap, so whether the portable device is in the passenger compartment or outside the passenger compartment Can be easily determined.

  Further, in the above configuration, the first transmission antenna and the second transmission antenna are installed at approximately the center in the front-rear direction of the vehicle interior near the right end of the vehicle interior and the left end of the vehicle interior, respectively. It has the feature of being.

  In the keyless entry system configured as described above, the first transmission antenna and the second transmission antenna are respectively installed at approximately the center of the vehicle interior in the front-rear direction near the right end of the vehicle interior and the left end of the vehicle interior. Therefore, it is possible to efficiently determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment using only two transmission antennas.

  The keyless entry system of the present invention includes a first distance that is a distance between the portable device and the first transmission antenna, a second distance that is a distance between the portable device and the second transmission antenna, and a first distance. Since the third distance, which is the total distance with the second distance, is used for the determination, it can be obtained with two transmission antennas even though only two transmission antennas are configured. No new information is required other than the first distance and the second distance. Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

It is a figure which shows schematic structure of a keyless entry system. It is a block diagram which shows each principal part structure of the vehicle-mounted apparatus and portable apparatus of a keyless entry system. It is a figure which shows the relationship between a keyless entry system and a vehicle. It is a figure explaining the principle regarding an ellipse. It is a table | surface which determines the position of the portable device in a keyless entry system. It is a figure which shows the example of the position of the portable machine in a keyless entry system. It is a schematic diagram which shows the structure of the keyless entry system which concerns on a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1386206662504_2
These are figures which show the schematic structure of the keyless entry system 100, and are the top views when the user 60 possessing the vehicle 50 and the portable device 20 is seen from upper direction. The keyless entry system 100 is mounted on, for example, a sedan type vehicle 50, and the vehicle 50 is provided with two vehicle-side transmission antennas 2 and a vehicle-side reception antenna 4. In this example, one vehicle-side receiving antenna 4 is installed in the instrument panel of the vehicle 50, and the first transmitting antenna 2a and the second transmitting antenna 2b as the vehicle-side transmitting antenna 2 are provided in the vehicle 50. One driver is installed near the center of the center pillar on the driver's seat and passenger seat. However, the arrangement of the two vehicle-side transmitting antennas 2 and the vehicle-side receiving antenna 4 mentioned here is an example, and other arrangements may be used. Note that the vehicle-side transmission antenna 2 of the keyless entry system 100 includes only two antennas, a first transmission antenna 2a and a second transmission antenna 2b.

  An in-vehicle device main body 10a is provided inside the vehicle 50, and the vehicle-side transmitting antenna 2 and the vehicle-side receiving antenna 4 are connected to the in-vehicle device main body 10a through wiring (not shown). The in-vehicle device 10 including the in-vehicle device main body 10a, the vehicle-side transmission antenna 2, and the vehicle-side reception antenna 4 has a function of performing wireless communication with the portable device 20 possessed by the user 60.

  As described above, the keyless entry system 100 performs wireless communication between the in-vehicle device 10 and the portable device 20 and performs authentication using an ID code or the like to lock (lock) or unlock (unlock) the door. Has a function to perform automatically (so-called passive function). The keyless entry system 100 can also permit the operation of the main switch without inserting a key into the key cylinder when the user 60 (driver) carrying the portable device 20 enters the vehicle interior 51. In addition, since such a function is well-known, description is abbreviate | omitted for the detail.

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These show the principal part structure of the vehicle equipment 10 and the portable device 20 which are used for the keyless entry system 100, respectively.

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As shown, the vehicle-side device 10 is configured by the vehicle-side transmission antenna 2, the vehicle-side reception antenna 4, and the vehicle-mounted device body 10a. The in-vehicle device body 10a includes a vehicle-side transmitter 1 (LF-TX), a vehicle-side receiver 3 (RF-RX), a vehicle-side controller 5 (CPU), and a vehicle-side oscillator 6 (LF-OSC). The vehicle-side storage unit 7 (MEM) and the drive signal transmission unit 8 (DS-TX) are configured.

  The vehicle-side transmission unit 1 includes a first vehicle-side transmission circuit 1a (TX1) and a second vehicle-side transmission circuit 1b (TX2). The first transmission antenna 2a and the second transmission antenna 2b described above are The first vehicle side transmission circuit 1a and the second vehicle side transmission circuit 1b are connected to each other. The vehicle-side receiving unit 3 has a built-in RSSI (Received Signal Strength Indication) circuit 3 a, an input end is connected to the vehicle-side receiving antenna 4, and an output end is connected to the vehicle-side control unit 5. . The vehicle-side oscillator 6 generates a low-frequency signal transmitted from the vehicle-side transmission unit 1 via the first transmission antenna 2a and the second transmission antenna 2b, and an output end is connected to the vehicle-side control unit 5. ing. The vehicle-side storage unit 7 stores a first ID assigned to the in-vehicle device 10 and a second ID assigned to the portable device 20 used together with the in-vehicle device 10, and the control end is the vehicle. It is connected to the side controller 5. The drive signal transmission unit 8 has an input end connected to the vehicle-side control unit 5 and an output end connected to the external connection terminal 8a.

  The low frequency signal output from the vehicle-side oscillator 6 is supplied to the vehicle-side control unit 5. When the low-frequency signal is supplied, the vehicle-side control unit 5 reads the first ID from the vehicle-side storage unit 7, adds necessary information including the read first ID to the low-frequency signal, and requests the signal. Form. Next, when the transmission timing of the request signal is set, the request signal is supplied to the vehicle-side transmission unit 1 under the control of the vehicle-side control unit 5. The 1st vehicle side transmission circuit 1a amplifies the supplied request signal to the signal level suitable for transmission, supplies the amplified request signal to the 1st transmission antenna 2a, and carries out radio transmission from the 1st transmission antenna 2a. Similarly, the second vehicle-side transmission circuit 1b amplifies the supplied low frequency signal to a signal level suitable for transmission, supplies the amplified low frequency signal to the second transmission antenna 2b, and supplies the second transmission antenna 2b. Wireless transmission from. The wireless transmission from the first transmission antenna 2a and the wireless transmission from the second transmission antenna 2b are performed alternately, and are not transmitted simultaneously.

  The vehicle-side receiving unit 3 receives and receives a high-frequency signal (answer signal) including the second ID and command signal of the portable device 20 wirelessly transmitted from the portable device 20 via the vehicle-side receiving antenna 4. The amplified answer signal is amplified to a predetermined signal level, and the amplified answer signal is supplied to the vehicle-side controller 5. The vehicle-side control unit 5 authenticates the second ID included in the answer signal using the second ID read from the vehicle-side storage unit 7, and when the authentication is established, the command included in the answer signal A drive signal is formed from the signal, and this drive signal is supplied to the drive signal transmitter 8. When the drive signal is supplied, the drive signal transmission unit 8 is driven to a motor (not shown) for locking and unlocking the corresponding door lock or a controlled mechanism (not shown) such as an engine start circuit. A signal is transmitted and the controlled mechanism is controlled according to the drive signal.

  As illustrated in FIG. 2, the portable device 20 includes a portable device side transmission unit 11 (RF-TX), a portable device side transmission antenna 12, a portable device side reception unit 13 (LF-RX), and a portable device side. The receiving antenna 14, the portable device side control unit 15, the portable device side oscillator 16 (RF-OSC), and the portable device side storage unit 17 (MEM) are configured. The portable device side receiving unit 13 includes an RSSI circuit 13a.

  The portable device side transmission unit 11 has an input end connected to the portable device side control unit 15 and an output end connected to the portable device side transmission antenna 12. The portable device side receiving unit 13 has an input end connected to the portable device side receiving antenna 14 and an output end connected to the portable device side control unit 15. The output terminal of the portable device side oscillator 16 is connected to the portable device side control unit 15. The portable device side storage unit 17 has a control end connected to the portable device side control unit 15.

  When the portable device-side transmitter 11 is supplied with a high-frequency signal (answer signal) including the second ID or command signal from the portable device-side controller 15, the answer signal is amplified to a signal level suitable for wireless transmission. Then, the amplified answer signal is wirelessly transmitted via the portable device-side transmitting antenna 12. The mobile device side receiving unit 13 receives a request signal (low frequency signal) including the first ID wirelessly transmitted from the in-vehicle device 10 via the mobile device side receiving antenna 14, and the received request signal is predetermined. The signal is amplified to the signal level and the amplified request signal is supplied to the portable device control unit 15. The portable device side oscillator 16 oscillates a high frequency signal, and the oscillated high frequency signal is supplied to the portable device side control unit 15. At this time, the portable device-side control unit 15 adds the necessary information signal such as the second ID and the command signal to the high-frequency signal to form an answer signal. This answer signal is obtained by adding a necessary information signal such as a second ID or a command signal by frequency modulation using a high frequency signal as a carrier wave, and is supplied to the portable device transmitting antenna 12 via the portable device transmitting unit 11. The The portable device storage unit 17 stores a first ID assigned to the in-vehicle device 10, a second ID assigned to the own portable device 20, and various command signals. Under the control of the side control unit 15, the first ID or the second ID and various command signals are appropriately read out.

  As described above, the vehicle-side receiver 3 includes the RSSI circuit 3a, and the portable device-side receiver 13 includes the RSSI circuit 13a. The RSSI circuit 3a can receive the answer signal wirelessly transmitted from the portable device 20 and detect the signal strength of the answer signal. Further, the RSSI circuit 13a can receive a request signal wirelessly transmitted from the in-vehicle device 10 and detect the signal strength of the request signal.

  In the vehicle-side control unit 5, based on the signal strength of the answer signal obtained by the RSSI circuit 3a, the distance between the portable device 20 and the first transmission antenna 2a and the distance between the portable device 20 and the second transmission antenna 2b. The distance between them can be calculated. In addition, the vehicle-side control unit 5 can calculate the total distance of these two distances. Similarly, the portable device side control unit 15 determines the distance between the portable device 20 and the first transmission antenna 2a, the portable device 20 and the second transmission signal based on the signal strength of the request signal obtained by the RSSI circuit 13a. The distance to the transmission antenna 2b can be calculated. In addition, the portable device side control unit 15 can calculate the total distance of these two distances. Further, the distance between the portable device 20 and the first transmission antenna 2a calculated by the vehicle-side control unit 5 and the portable device-side control unit 15, the distance between the portable device 20 and the second transmission antenna 2b, and these The total distance of the two distances can be stored in the vehicle-side storage unit 7 and the portable device-side storage unit 17. In the future, the distance between the portable device 20 and the first transmission antenna 2a will be referred to as a first distance L1, and the distance between the portable device 20 and the second transmission antenna 2b will be referred to as a second distance L2. Further, the total distance of the first distance L1 and the second distance L2, that is, L1 + L2 is set as the third distance L3.

Next, using the in-vehicle device 10 and the portable device 20 having the above-described configuration, a method for determining whether the portable device 20 is in the vehicle interior 51 or the vehicle exterior of the vehicle 50, that is, the inside / outside determination method,
1386206662504_5
4 will be described.

  FIG. 3 is a diagram illustrating a relationship between the keyless entry system 100 and the vehicle 50, and FIG. 4 is a diagram illustrating a principle related to a general ellipse.

1386206662504_6
As shown in FIG. 2, in the embodiment, the first transmitting antenna 2a is installed at a substantially central position in the front-rear direction near the right end of the vehicle interior 51, specifically, at the position of the right center pillar. Further, the second transmission antenna 2b is installed at a substantially central position in the front-rear direction near the left end of the vehicle interior 51, specifically, at the position of the left center pillar. Moreover, the vehicle interior 51 in the vehicle 50 is represented by a two-dot chain line.

As described above, the request signal is transmitted from the first transmission antenna 2a and the second transmission antenna 2b toward the inside and the outside of the vehicle 50.
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, The range in which the portable device 20 can receive the request signal from the first transmission antenna 2a is indicated by a first circle C1, and the range in which the portable device 20 can receive the request signal from the second transmission antenna 2b is indicated by a second circle C2. . The first circle C1 is a circle having a radius R1 with the installation position of the first transmission antenna 2a as the center. Similarly, the second circle C2 is a circle having a radius R2 with the installation position of the second transmission antenna 2b as the center. Here, the radius R1 is the signal arrival distance of the request signal from the first transmission antenna 2a, and the radius R2 is the signal arrival distance of the request signal from the second transmission antenna 2b. In the keyless entry system 100, the radius R1 and the radius R2 are the same value.

1386206662504_8
As shown, the end of the first circle C1 in the Y2 direction (the left side of the vehicle 50) hangs on the end of the left door of the vehicle 50. Further, the end of the second circle C2 in the Y1 direction (the right side of the vehicle 50) is hung on the end of the right door of the vehicle 50. Therefore, the region where the first circle C1 and the second circle C2 overlap defines the space from the right door of the vehicle 50 to the left door of the vehicle 50. In addition, the area | region where the area | region 910 and the area | region 911 which are the encryption code request signal transmission area of the vehicle equipment remote control system 900 described in patent document 1 as the prior art mentioned above overlapped with this 1st circle | round | yen C1 and 1st. This corresponds to the area where two circles C2 overlap.

  The region where the first circle C1 and the second circle C2 overlap is the first condition for determining that the portable device 20 is in the vehicle interior 51 of the vehicle 50. That is, in order to determine that the portable device 20 is in the passenger compartment 51 of the vehicle 50, the portable device 20 uses the installation position of the first transmission antenna 2a as a center point, and the signal arrival distance of the first transmission antenna 2a is defined as the radius R2. It is necessary to be inside the second circle C2. At the same time, it is also necessary for the portable device 20 to be inside the second circle C2 with the installation position of the second transmission antenna 2b as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. In other words, the radius R1 that is the signal arrival distance of the first transmission antenna 2a and the radius R2 that is the signal arrival distance of the second transmission antenna 2b are set as predetermined threshold values, respectively, and the first distance L1 is compared with the radius R1, The two distance L2 is compared with the radius R2. The first condition is that the first distance L1 is not more than the radius R1, and the second distance L2 is not more than the radius R2. Accordingly, the first condition is the first distance L1 ≦ radius R1 and the second distance L2 ≦ radius R2.

However, in the region where the first circle C1 and the second circle C2 overlap,
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The area shown by cross hatching is also included. This area corresponds to the engine room and the trunk room in the vehicle 50, and is not an area that can be said to be the vehicle interior 51. Therefore, it is necessary to delete these areas from the area where the first circle C1 and the second circle C2 overlap.

In the present invention, the second condition is added to delete these areas. And as the second condition
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An ellipse D1 indicated by a broken line is adopted. Here, the ellipse D1 is an ellipse whose focal point is the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. That is, the second condition is that the portable device 20 is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as focal points.

  Generally, a law is known that an ellipse is a figure whose sum of distances from two fixed points is constant (the two fixed points are then called the focal point of the ellipse). As shown in FIG. 4, the distance between one point a1 on the circumference of the ellipse D0 and one focal point f1 of the ellipse D0 is a distance A1, and the distance between the single point a1 and the other focal point f2 of the ellipse D0 is The distance is A2. The distance between the other point b1 on the circumference of the ellipse D0 and one focus f1 of the ellipse D0 is a distance B1, and the distance between the point b1 and the other focus f2 of the ellipse D0 is a distance B2. To do. At this time, the sum of the distance A1 and the distance A2, that is, A1 + A2, is equal to the sum of the distance B1 and the distance B2, that is, B1 + B2, and the value thereof is constant. The relationship is established regardless of which point a1 and point b1 are on the ellipse D0. Expressed by the equation, A1 + A2 = B1 + B2 = K1 (constant).

  When the above-mentioned law concerning the ellipse is applied to the keyless entry system 100 of the present invention, the ellipse D1 shown in FIG. 3 corresponds to the ellipse D0 shown in FIG. 4, and the installation position of the first transmission antenna 2a is one focal point of the ellipse D0. This corresponds to f1, and the installation position of the second transmission antenna 2b corresponds to the other focal point f2 of the ellipse D0. Therefore, assuming that the ellipse D0 and the ellipse D1 have the same shape, the portable device 20 is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as the focal points, respectively. That is the second condition. In other words, the second condition is that the sum of the first distance L1 and the second distance L2, that is, the third distance L3 is L3 ≦ K1 (constant). Conversely, the fact that the portable device 20 is outside the ellipse D1 means that the third distance L3 is L3> K1 (constant). FIG. 3 shows a state where L3> K1 (constant).

1386206662504_11
As shown by a broken line in FIG. 4, the end of the ellipse D1 on the front side (X2 side) of the vehicle 50 is in contact with the front end of the windshield of the vehicle 50, and the rear side (X1 side) of the vehicle 50 in the ellipse D1. Is in contact with the rear end of the rear glass of the vehicle 50. Further, the right end (Y1 side) end of the vehicle 50 in the ellipse D1 is on the right side (Y1 side) from the right end portion of the vehicle 50, and the left end (Y2 side) end of the vehicle 50 in the ellipse D1 is the left end of the vehicle 50. On the left side (Y2 side). Accordingly, by adopting the second condition when the portable device 20 is inside the ellipse D1, an area that includes the entire interior of the vehicle interior 51 and is outside the vehicle interior in the front-rear direction of the vehicle 50, that is, the engine room of the vehicle 50. And the area corresponding to the trunk room can be deleted.

  As described above, when both the first condition and the second condition described above are satisfied, it can be determined that the portable device 20 is in the vehicle interior 51. That is, the portable device 20 is inside the first circle C1 having the signal transmission distance of the first transmission antenna 2a as the radius R1 with the installation position of the first transmission antenna 2a as the center point, and the second transmission antenna 2b. The installation position of the first transmission antenna 2b and the installation position of the second transmission antenna 2b are within the second circle C2 having the installation position as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. It can be determined that the portable device 20 is in the vehicle interior 51 when it is inside the ellipse D <b> 1 that is the focal point.

  In the keyless entry system 100, a first distance L1 that is a distance between the portable device 20 and the first transmission antenna 2a, a second distance L2 that is a distance between the portable device 20 and the second transmission antenna 2b, The third distance L3, which is the total distance of the first distance L1 and the second distance L2, is used for the inside / outside determination. As a result, although the vehicle-side transmitting antenna 2 is composed of only the first transmitting antenna 2a and the second transmitting antenna 2b, the first distance L1 and the second distance obtained by the two antennas can be reduced. No new information is required other than the 2-distance L2. Therefore, it is possible to accurately determine whether the portable device 20 is in the passenger compartment 51 or outside the passenger compartment without increasing the cost.

  Further, the keyless entry system 100 determines whether the portable device 20 is inside or outside the ellipse D1 whose focal points are the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. Added to the condition. As a result, the area outside the passenger compartment in the front-rear direction of the vehicle 50 can be removed from the area where the first circle C1 and the second circle C2 overlap, so that the portable device 20 is located in the passenger compartment 51 or outside the passenger compartment. It is easy to accurately determine whether or not

  Further, in the keyless entry system 100, the first transmission antenna 2a and the second transmission antenna 2b are installed in the vicinity of the right end of the vehicle interior 51 and the left end of the vehicle interior 51, respectively, in the center of the vehicle interior 51 in the front-rear direction. Has been. Therefore, it is possible to efficiently determine whether the portable device 20 is in the vehicle interior 51 or outside the vehicle interior using only the two vehicle-side transmission antennas 2.

  Next, the determination of the position of the portable device 20 when the portable device 20 is actually in the vehicle interior 51 or outside the vehicle compartment will be described with reference to FIGS. 5 and 6. FIG. 5 illustrates a case where the inside / outside determination of the position where the portable device 20 exists is performed for three examples (portable device 20a, portable device 20b, and portable device 20c) where the portable device 20 exists in the keyless entry system 100. It is a table. FIG. 6 is a diagram illustrating specific positions of the portable device 20a, the portable device 20b, and the portable device 20c with respect to the vehicle.

  In the table of FIG. 5, a case where the first condition or the second condition is satisfied is indicated as “◯”, and a case where the first condition or the second condition is not satisfied is indicated as “X”. In addition, in the determination result, a case where the portable device 20 exists in the vehicle interior 51 is indicated by ◯, and a case where the portable device 20 exists outside the vehicle interior is indicated by x. The first distance L1 between the portable device 20 and the installation position of the first transmission antenna 2a and the second distance L2 between the portable device 20 and the installation position of the second transmission antenna 2b are the RSSI circuit described above. It has already been obtained based on the signal strength of the request signal or the answer signal obtained by the 3a or RSSI circuit 13a. Further, the third distance L3a, which is the first distance L1 + the second distance L2, has already been obtained by the vehicle-side control unit 5 or the portable device-side control unit 15.

  In the table of FIG. 5, in the case of the portable device 20a, the first distance L1a is smaller than the radius R1 of the first circle C1, that is, L1a <R1, based on the signal strength of the request signal or the answer signal. The two distance L2a is required to be smaller than the radius R2 of the second circle C2, that is, L2a <R2. Further, the third distance L3a, which is the first distance L1a + the second distance L2a, is required to be smaller than a certain value K1 representing the shape of the ellipse D1, that is, L3a <K1. Therefore, since both the first condition and the second condition are satisfied, it can be determined that the portable device 20a is in the vehicle interior 51.

  When this result is confirmed in FIG. 6, the portable device 20a is inside the first circle C1 with the installation position of the first transmission antenna 2a as the center point and the signal arrival distance of the first transmission antenna 2a as the radius R1. At the same time, the portable device 20a is located inside the second circle C2 having the installation position of the second transmission antenna 2b as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. Therefore, the first condition of the inside / outside determination for the portable device 20a is satisfied. Moreover, the portable device 20a is located inside an ellipse D1 that has the focal point at the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. Therefore, the second condition of the inside / outside determination for the portable device 20a is also satisfied. Therefore, also from FIG. 6, it can be determined that the portable device 20 a exists in the vehicle interior 51. OK

  In the table of FIG. 5, in the case of the portable device 20b, similarly, the first distance L1b is smaller than the radius R1 of the first circle C1, that is, L1b <R1, and the second distance L2b is smaller than the radius R2 of the second circle C2. That is, it is required that L2b <R2. Further, the third distance L3b, which is the first distance L1b + the second distance L2b, is required to be larger than a certain value K1 representing the shape of the ellipse D1, that is, L3b> K1. Therefore, although the first condition is satisfied but the second condition is not satisfied, it can be determined that the portable device 20b is outside the passenger compartment.

  When this result is confirmed in FIG. 6, the portable device 20b is inside the first circle C1 and inside the second circle C2. Therefore, the first condition of the inside / outside determination for the portable device 20a is satisfied. However, the portable device 20b is outside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as the focal points, respectively. Therefore, the second condition for the inside / outside determination for the portable device 20b is not satisfied. Therefore, it can be determined from FIG. 6 that the portable device 20a exists outside the passenger compartment.

  In the table of FIG. 5, in the case of the portable device 20c, similarly, the first distance L1c is smaller than the radius R1 of the first circle C1, that is, L1b <R1, and the second distance L2c is larger than the radius R2 of the second circle C2. That is, it is required that L2c> R2. Further, the third distance L3c, which is the first distance L1b + the second distance L2b, is required to be smaller than a fixed value K1 representing the shape of the ellipse D1, that is, L3b <K1. Therefore, although the second condition is satisfied, the first condition is not satisfied, and therefore it can be determined that the portable device 20a is outside the passenger compartment.

  When this result is confirmed in FIG. 6, the portable device 20c is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as focal points. Therefore, the second condition of the inside / outside determination for the portable device 20c is satisfied. However, the portable device 20c is inside the first circle C1, but outside the second circle C2. Therefore, the first condition of the inside / outside determination for the portable device 20c is not satisfied. Therefore, it can be determined that the portable device 20a exists outside the passenger compartment.

  As described above, the keyless entry system of the present invention has the first distance, which is the distance between the portable device and the first transmission antenna, and the second distance, which is the distance between the portable device and the second transmission antenna. And the third distance, which is the total distance of the first distance and the second distance, is used for the determination, so that although there are only two transmission antennas, two No new information is required other than the first distance and the second distance obtained by the transmitting antenna. Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

  The present invention is not limited to the description of the above embodiment, and can be implemented with appropriate modifications in a mode in which the effect is exhibited. For example, the keyless entry system of the present invention may include components equivalent to the components shown in FIG. In the keyless entry system according to the present invention, a sedan type vehicle is used as the vehicle. However, the vehicle type may be a one-box car type or other types of vehicles, and the vehicle interior corresponding to the type may be used. Each element such as the installation position of the transmission antenna may be set by defining the shape of the transmission antenna.

DESCRIPTION OF SYMBOLS 1 Vehicle side transmission part 2 Vehicle side transmission antenna 2a 1st transmission antenna 2b 2nd transmission antenna 3 Vehicle side reception part 4 Vehicle side reception antenna 5 Vehicle side control part 6 Vehicle side oscillator 7 Vehicle side memory | storage part 8 Drive signal transmission part 10 In-vehicle device 10a In-vehicle device main body 11 Portable device side transmitting unit 12 Portable device side transmitting antenna 13 Portable device side receiving unit 14 Portable device side receiving antenna 15 Portable device side control unit 16 Portable device side oscillator 17 Portable device side storage unit 20 Portable device 50 Vehicle 51 Car interior 52 Car exterior 60 User 100 Keyless entry system L1 1st distance L2 2nd distance L3 3rd distance R1 Radius R2 Radius C1 1st circle C2 2nd circle D1 Ellipse

  The present invention relates to a keyless entry system that locks or unlocks a door of a vehicle and starts an engine by performing wireless communication between the in-vehicle device and the portable device, and particularly, automatically between the in-vehicle device and the portable device. The present invention relates to a passive keyless entry system having a function for communication.

  In moving vehicles such as automobiles, when the automobile is not in use, the door of the automobile door is locked to prevent the automobile from being stolen or being intruded into the automobile and damaging the internal devices. Provided. Conventionally, the door lock is locked or unlocked by inserting a key for starting the engine into the key hole. However, for convenience, the key of the portable device is not inserted without inserting the key into the key hole. A so-called keyless entry system that unlocks and locks a door lock by operating a switch is used. Further, in recent years, a so-called passive device that unlocks and locks a door lock can be achieved by holding a predetermined portable device and operating a vehicle door switch located in a predetermined region without operating the portable device switch. A keyless entry system is used. Furthermore, the passive keyless entry system has an electrical authentication function for starting the engine, and the safety is improved by preventing the engine from starting unless authentication is established between the car body and the portable device. is there.

  The operation of the keyless entry system is a low-frequency signal including a wake-up signal from a vehicle-mounted device when a person holding a portable device already registered in the vehicle-mounted device mounted on the vehicle approaches the vehicle. Send a request signal. When the portable device receives the request signal, the portable device responds and transmits an answer signal that is a high-frequency signal including a command signal. When the on-vehicle device receives the answer signal, the on-vehicle device is included in the answer signal. The controlled device is controlled according to the command signal. The control is, for example, unlocking the door of the automobile or starting the engine of the automobile, so that the driver can drive the automobile.

  The keyless entry system in which such a series of operations is performed includes a function that contributes to starting the engine when the portable device is inside the vehicle compartment, and locking the door lock when the portable device is outside the vehicle compartment. Some have functions that contribute to unlocking. In addition, in order to prevent misplacement of the portable device in the vehicle interior, there is a device having a function of preventing the door from being locked when the portable device is in the vehicle interior.

  In such a keyless entry system, it is important to detect with high accuracy whether the portable device is inside or outside the vehicle. As a keyless entry system for performing detection and determination, there is known a system in which a plurality of antennas for transmitting request signals are arranged in a vehicle interior or in a vehicle interior and a vehicle interior, respectively. According to this type of keyless entry system, since the request signal is transmitted from the in-vehicle device via the plurality of antennas, if the portable device is in a predetermined range outside the vehicle interior or outside the vehicle interior, Thus, it is possible to reliably transmit and receive radio signals between the in-vehicle device and the portable device. Accordingly, it can be accurately determined whether the portable device is in the vehicle interior or the vehicle interior.

  In any of these keyless entry systems, when a legitimate request signal is transmitted via two or more antennas, the portable device that has received one of the request signals responds with an answer signal. Send. Then, the place where the portable device is located is determined based on the fact that the in-vehicle device receives an answer signal from the portable device.

  For example, the in-vehicle device remote control system described in Patent Document 1 discloses a configuration that can reduce the cost without impairing security and convenience and using only two transmission antennas. An in-vehicle device remote control system 900 described in Patent Literature 1 is shown in FIG.

The encryption code request signal is alternately transmitted from the antenna 906 and the antenna 907 which are encryption code request signal transmission antennas disposed on the left and right doors. As a result, if a return code can be received from the portable wireless device 950 for any transmission, the portable wireless device 950 exists in an area where both the right-down oblique line area 910 and the right-up diagonal line area 911 shown in FIG. 7 overlap. And the area coincides with the area in the vehicle.

  By this method, it is possible to determine whether or not the portable wireless device 950 exists in the vehicle interior, and the position of the portable wireless device 950 can be determined. Therefore, while it is determined that the portable wireless device 950 is in the passenger compartment, if the driver of the vehicle goes out of the passenger compartment without holding the portable wireless device 950 and tries to lock the door, the door cannot be locked. Alarms such as sounding horns can be generated. In other words, it is possible to call attention for preventing the portable wireless device 950 from being misplaced and improve the security performance. In addition, since only two antennas, the right door antenna 906 and the left door antenna 907, are used as transmitting antennas, compared to the case where three or more antennas are required, the cost of parts and the number of man-hours can be reduced. It can be reduced.

JP 2004-084406 A

  However, the in-vehicle device remote control system 900 described in Patent Document 1 has the following problems. An area 910 within the encryption code request signal transmission area by the antenna 906 in the vicinity of the right door (a right-down hatching area in FIG. 7) and an area 911 within the encryption code request signal transmission area by the antenna 907 in the vicinity of the left door (at the right in FIG. 7) Each rising hatch area is represented by a circular shape centered on the antenna installation position. Therefore, a region where the region 910 and the region 911 overlap (hereinafter referred to as an overlapping region) has a shape in which the tip protrudes in the front-rear direction of the vehicle, that is, a rugby ball shape in plan view (shown by a broken line in FIG. 7). As a result, if it is determined that the overlapping region is in the passenger compartment, it may be determined that the portable wireless device 950 is outside the passenger compartment at the four corners of the actual passenger compartment, even though the portable wireless device 950 is in the passenger compartment. It was. Further, in order to solve this problem, when the overlapping area is widened, the overlapping area having a rugby ball shape in plan view protrudes from the shape of the passenger compartment having a substantially rectangular shape in plan view. . For this reason, there is a possibility that the portable wireless device 950 may be determined to be in the passenger compartment even though the portable wireless device 950 is outside the vehicle.

  Of course, if the position of the portable wireless device 950 can be accurately determined with respect to the front-rear and left-right directions of the passenger compartment, it can be accurately determined whether the portable wireless device 950 is inside or outside the passenger compartment. However, in order to accurately determine the position of the portable wireless device 950 in this way, only two transmission antennas are needed. For example, if the determination is made using the trigonometric method, the position of the portable wireless device 950 can be accurately determined. To that end, at least three transmission antennas are required. However, increasing the number of transmit antennas results in increased costs associated with the keyless entry system.

  The present invention has been made in view of such a technical background, and an object of the present invention is to provide a portable device in a vehicle interior without increasing costs by configuring the transmission antenna with only two transmission antennas. An object is to provide a keyless entry system that can accurately determine whether the vehicle is outside the vehicle compartment.

  In order to solve this problem, a keyless entry system of the present invention is a keyless entry system including an in-vehicle device provided in a vehicle and a portable device possessed by a user, and the in-vehicle device is included in the portable device. A vehicle-side transmission unit that transmits a request signal; a vehicle-side transmission antenna connected to the vehicle-side transmission unit; a vehicle-side reception unit that receives an answer signal from the portable device; A vehicle-side control unit that controls the mobile device, the portable device receiving a request signal from the vehicle-side transmission antenna, and a portable device-side transmission unit transmitting the answer signal. A vehicle-side control unit that performs predetermined control, and the vehicle-side transmission antenna includes two transmission antennas, a first transmission antenna and a second transmission antenna, provided at predetermined positions. The vehicle-side receiver or the portable device-side receiver has a circuit that detects the signal strength of the answer signal or the request signal, and the vehicle-side controller or the portable device-side controller is A first distance that is a distance between the portable device and the first transmission antenna and a second distance that is a distance between the portable device and the second transmission antenna are based on the signal strength. By calculating and comparing the first distance, the second distance, and the third distance, which is the total distance of the first distance and the second distance, respectively with a predetermined threshold, It has the characteristic of determining whether the vehicle is inside or outside the vehicle.

  The keyless entry system configured as described above includes a first distance that is a distance between the portable device and the first transmitting antenna, a second distance that is a distance between the portable device and the second transmitting antenna, Since the third distance, which is the total distance of the first distance and the second distance, is used for the determination, the two transmission antennas are used even though only two transmission antennas are configured. No new information is required other than the first distance and the second distance obtained in (1). Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

In the above configuration, the portable device has a radius of a first signal arrival distance in which a signal intensity transmitted from the first transmission antenna is a predetermined value or more with the installation position of the first transmission antenna as a central point. Inside the first circle, and
The second transmission antenna is located inside a second circle having a radius that is a second signal arrival distance in which a signal intensity transmitted from the second transmission antenna is a predetermined value or more with the installation position of the second transmission antenna as a center point; and
The installation position of the first transmission antenna and the installation position of the second transmission antenna are used as focal points, respectively, and the third signal arrival distance, which is the total distance of the first signal arrival distance and the second signal arrival distance, is used. When inside the ellipse
It is characterized in that it is determined that the portable device is in the vehicle interior.

  The keyless entry system configured as described above is a condition for determining whether the portable device is inside or outside the ellipse that has the installation position of the first transmission antenna and the installation position of the second transmission antenna as the focal points. By adding to the above, it is possible to remove the area outside the passenger compartment in the longitudinal direction of the vehicle from the area where the first circle and the second circle overlap, so whether the portable device is in the passenger compartment or outside the passenger compartment Can be easily determined.

  Further, in the above configuration, the first transmission antenna and the second transmission antenna are installed at approximately the center in the front-rear direction of the vehicle interior near the right end of the vehicle interior and the left end of the vehicle interior, respectively. It has the feature of being.

  In the keyless entry system configured as described above, the first transmission antenna and the second transmission antenna are respectively installed at approximately the center of the vehicle interior in the front-rear direction near the right end of the vehicle interior and the left end of the vehicle interior. Therefore, it is possible to efficiently determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment using only two transmission antennas.

  The keyless entry system of the present invention includes a first distance that is a distance between the portable device and the first transmission antenna, a second distance that is a distance between the portable device and the second transmission antenna, and a first distance. Since the third distance, which is the total distance with the second distance, is used for the determination, it can be obtained with two transmission antennas even though only two transmission antennas are configured. No new information is required other than the first distance and the second distance. Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

It is a figure which shows schematic structure of a keyless entry system. It is a block diagram which shows each principal part structure of the vehicle-mounted apparatus and portable apparatus of a keyless entry system. It is a figure which shows the relationship between a keyless entry system and a vehicle. It is a figure explaining the principle regarding an ellipse. It is a table | surface which determines the position of the portable device in a keyless entry system. It is a figure which shows the example of the position of the portable machine in a keyless entry system. It is a schematic diagram which shows the structure of the keyless entry system which concerns on a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of the keyless entry system 100, and is a plan view when a user 60 having the vehicle 50 and the portable device 20 is viewed from above. The keyless entry system 100 is mounted on, for example, a sedan type vehicle 50, and the vehicle 50 is provided with two vehicle-side transmission antennas 2 and a vehicle-side reception antenna 4. In this example, one vehicle-side receiving antenna 4 is installed in the instrument panel of the vehicle 50, and the first transmitting antenna 2a and the second transmitting antenna 2b as the vehicle-side transmitting antenna 2 are provided in the vehicle 50. One driver is installed near the center of the center pillar on the driver's seat and passenger seat. However, the arrangement of the two vehicle-side transmitting antennas 2 and the vehicle-side receiving antenna 4 mentioned here is an example, and other arrangements may be used.
Note that the vehicle-side transmission antenna 2 of the keyless entry system 100 includes only two antennas, a first transmission antenna 2a and a second transmission antenna 2b.

  An in-vehicle device main body 10a is provided inside the vehicle 50, and the vehicle-side transmitting antenna 2 and the vehicle-side receiving antenna 4 are connected to the in-vehicle device main body 10a through wiring (not shown). The in-vehicle device 10 including the in-vehicle device main body 10a, the vehicle-side transmission antenna 2, and the vehicle-side reception antenna 4 has a function of performing wireless communication with the portable device 20 possessed by the user 60.

  As described above, the keyless entry system 100 performs wireless communication between the in-vehicle device 10 and the portable device 20 and performs authentication using an ID code or the like to lock (lock) or unlock (unlock) the door. Has a function to perform automatically (so-called passive function). The keyless entry system 100 can also permit the operation of the main switch without inserting a key into the key cylinder when the user 60 (driver) carrying the portable device 20 enters the vehicle interior 51. In addition, since such a function is well-known, description is abbreviate | omitted for the detail.

FIG. 2 shows a main configuration of each of the in-vehicle device 10 and the portable device 20 used in the keyless entry system 100.

As shown in FIG. 2 , the vehicle-side device 10 is configured by the vehicle-side transmitting antenna 2, the vehicle-side receiving antenna 4, and the vehicle-mounted device body 10a. The in-vehicle device body 10a includes a vehicle-side transmitter 1 (LF-TX), a vehicle-side receiver 3 (RF-RX), a vehicle-side controller 5 (CPU), and a vehicle-side oscillator 6 (LF-OSC). The vehicle-side storage unit 7 (MEM) and the drive signal transmission unit 8 (DS-TX) are configured.

  The vehicle-side transmission unit 1 includes a first vehicle-side transmission circuit 1a (TX1) and a second vehicle-side transmission circuit 1b (TX2). The first transmission antenna 2a and the second transmission antenna 2b described above are The first vehicle side transmission circuit 1a and the second vehicle side transmission circuit 1b are connected to each other. The vehicle-side receiving unit 3 has a built-in RSSI (Received Signal Strength Indication) circuit 3 a, an input end is connected to the vehicle-side receiving antenna 4, and an output end is connected to the vehicle-side control unit 5. . The vehicle-side oscillator 6 generates a low-frequency signal transmitted from the vehicle-side transmission unit 1 via the first transmission antenna 2a and the second transmission antenna 2b, and an output end is connected to the vehicle-side control unit 5. ing. The vehicle-side storage unit 7 stores a first ID assigned to the in-vehicle device 10 and a second ID assigned to the portable device 20 used together with the in-vehicle device 10, and the control end is the vehicle. It is connected to the side controller 5. The drive signal transmission unit 8 has an input end connected to the vehicle-side control unit 5 and an output end connected to the external connection terminal 8a.

The low frequency signal output from the vehicle-side oscillator 6 is supplied to the vehicle-side control unit 5. When the low-frequency signal is supplied, the vehicle-side control unit 5 reads the first ID from the vehicle-side storage unit 7, adds necessary information including the read first ID to the low-frequency signal, and requests the signal. Form. Next, when the transmission timing of the request signal is set, the request signal is supplied to the vehicle-side transmission unit 1 under the control of the vehicle-side control unit 5. The 1st vehicle side transmission circuit 1a amplifies the supplied request signal to the signal level suitable for transmission, supplies the amplified request signal to the 1st transmission antenna 2a, and carries out radio transmission from the 1st transmission antenna 2a. Similarly, the second vehicle-side transmission circuit 1b amplifies the supplied low frequency signal to a signal level suitable for transmission, supplies the amplified low frequency signal to the second transmission antenna 2b, and supplies the second transmission antenna 2b. Wireless transmission from.
The wireless transmission from the first transmission antenna 2a and the wireless transmission from the second transmission antenna 2b are performed alternately, and are not transmitted simultaneously.

  The vehicle-side receiving unit 3 receives and receives a high-frequency signal (answer signal) including the second ID and command signal of the portable device 20 wirelessly transmitted from the portable device 20 via the vehicle-side receiving antenna 4. The amplified answer signal is amplified to a predetermined signal level, and the amplified answer signal is supplied to the vehicle-side controller 5. The vehicle-side control unit 5 authenticates the second ID included in the answer signal using the second ID read from the vehicle-side storage unit 7, and when the authentication is established, the command included in the answer signal A drive signal is formed from the signal, and this drive signal is supplied to the drive signal transmitter 8. When the drive signal is supplied, the drive signal transmission unit 8 is driven to a motor (not shown) for locking and unlocking the corresponding door lock or a controlled mechanism (not shown) such as an engine start circuit. A signal is transmitted and the controlled mechanism is controlled according to the drive signal.

  As illustrated in FIG. 2, the portable device 20 includes a portable device side transmission unit 11 (RF-TX), a portable device side transmission antenna 12, a portable device side reception unit 13 (LF-RX), and a portable device side. The receiving antenna 14, the portable device side control unit 15, the portable device side oscillator 16 (RF-OSC), and the portable device side storage unit 17 (MEM) are configured. The portable device side receiving unit 13 includes an RSSI circuit 13a.

  The portable device side transmission unit 11 has an input end connected to the portable device side control unit 15 and an output end connected to the portable device side transmission antenna 12. The portable device side receiving unit 13 has an input end connected to the portable device side receiving antenna 14 and an output end connected to the portable device side control unit 15. The output terminal of the portable device side oscillator 16 is connected to the portable device side control unit 15. The portable device side storage unit 17 has a control end connected to the portable device side control unit 15.

  When the portable device-side transmitter 11 is supplied with a high-frequency signal (answer signal) including the second ID or command signal from the portable device-side controller 15, the answer signal is amplified to a signal level suitable for wireless transmission. Then, the amplified answer signal is wirelessly transmitted via the portable device-side transmitting antenna 12. The mobile device side receiving unit 13 receives a request signal (low frequency signal) including the first ID wirelessly transmitted from the in-vehicle device 10 via the mobile device side receiving antenna 14, and the received request signal is predetermined. The signal is amplified to the signal level and the amplified request signal is supplied to the portable device control unit 15. The portable device side oscillator 16 oscillates a high frequency signal, and the oscillated high frequency signal is supplied to the portable device side control unit 15. At this time, the portable device-side control unit 15 adds the necessary information signal such as the second ID and the command signal to the high-frequency signal to form an answer signal. This answer signal is obtained by adding a necessary information signal such as a second ID or a command signal by frequency modulation using a high frequency signal as a carrier wave, and is supplied to the portable device transmitting antenna 12 via the portable device transmitting unit 11. The The portable device storage unit 17 stores a first ID assigned to the in-vehicle device 10, a second ID assigned to the own portable device 20, and various command signals. Under the control of the side control unit 15, the first ID or the second ID and various command signals are appropriately read out.

  As described above, the vehicle-side receiver 3 includes the RSSI circuit 3a, and the portable device-side receiver 13 includes the RSSI circuit 13a. The RSSI circuit 3a can receive the answer signal wirelessly transmitted from the portable device 20 and detect the signal strength of the answer signal. Further, the RSSI circuit 13a can receive a request signal wirelessly transmitted from the in-vehicle device 10 and detect the signal strength of the request signal.

  In the vehicle-side control unit 5, based on the signal strength of the answer signal obtained by the RSSI circuit 3a, the distance between the portable device 20 and the first transmission antenna 2a and the distance between the portable device 20 and the second transmission antenna 2b. The distance between them can be calculated. In addition, the vehicle-side control unit 5 can calculate the total distance of these two distances. Similarly, the portable device side control unit 15 determines the distance between the portable device 20 and the first transmission antenna 2a, the portable device 20 and the second transmission signal based on the signal strength of the request signal obtained by the RSSI circuit 13a. The distance to the transmission antenna 2b can be calculated. In addition, the portable device side control unit 15 can calculate the total distance of these two distances. Further, the distance between the portable device 20 and the first transmission antenna 2a calculated by the vehicle-side control unit 5 and the portable device-side control unit 15, the distance between the portable device 20 and the second transmission antenna 2b, and these The total distance of the two distances can be stored in the vehicle-side storage unit 7 and the portable device-side storage unit 17. In the future, the distance between the portable device 20 and the first transmission antenna 2a will be referred to as a first distance L1, and the distance between the portable device 20 and the second transmission antenna 2b will be referred to as a second distance L2. Further, the total distance of the first distance L1 and the second distance L2, that is, L1 + L2 is set as the third distance L3.

Next, a method for determining whether the portable device 20 is in the vehicle interior 51 or outside the vehicle interior of the vehicle 50 using the in-vehicle device 10 and the mobile device 20 having the above-described configuration, that is, the inside / outside determination method will be described with reference to FIG. It demonstrates using thru | or 4.

  FIG. 3 is a diagram illustrating a relationship between the keyless entry system 100 and the vehicle 50, and FIG. 4 is a diagram illustrating a principle related to a general ellipse.

As shown in FIG. 3 , in the embodiment, the first transmission antenna 2 a is installed at a substantially central position in the front-rear direction near the right end of the vehicle interior 51, specifically, at the position of the right center pillar. Further, the second transmission antenna 2b is installed at a substantially central position in the front-rear direction near the left end of the vehicle interior 51, specifically, at the position of the left center pillar. Moreover, the vehicle interior 51 in the vehicle 50 is represented by a two-dot chain line.

As described above, the request signal is transmitted from the first transmission antenna 2a and the second transmission antenna 2b toward the inside and the outside of the vehicle 50. In FIG. 3 , the receivable range of the request signal from the first transmitting antenna 2a by the portable device 20 is the first circle C1, and the receivable range of the request signal from the second transmitting antenna 2b by the portable device 20 is the second circle C2. It shows with. The first circle C1 is a circle having a radius R1 with the installation position of the first transmission antenna 2a as the center. Similarly, the second circle C2 is a circle having a radius R2 with the installation position of the second transmission antenna 2b as the center. Here, the radius R1 is the signal arrival distance of the request signal from the first transmission antenna 2a, and the radius R2 is the signal arrival distance of the request signal from the second transmission antenna 2b. In the keyless entry system 100, the radius R1 and the radius R2 are the same value.

As shown in FIG. 3 , the end of the first circle C <b> 1 in the Y2 direction (the left side of the vehicle 50) is hung on the end of the left door of the vehicle 50. Further, the end of the second circle C2 in the Y1 direction (the right side of the vehicle 50) is hung on the end of the right door of the vehicle 50. Therefore, the region where the first circle C1 and the second circle C2 overlap defines the space from the right door of the vehicle 50 to the left door of the vehicle 50. In addition, the area | region where the area | region 910 and the area | region 911 which are the encryption code request signal transmission area of the vehicle equipment remote control system 900 described in patent document 1 as the prior art mentioned above overlapped with this 1st circle | round | yen C1 and 1st. This corresponds to the area where two circles C2 overlap.

  The region where the first circle C1 and the second circle C2 overlap is the first condition for determining that the portable device 20 is in the vehicle interior 51 of the vehicle 50. That is, in order to determine that the portable device 20 is in the passenger compartment 51 of the vehicle 50, the portable device 20 uses the installation position of the first transmission antenna 2a as a center point, and the signal arrival distance of the first transmission antenna 2a is defined as the radius R2. It is necessary to be inside the second circle C2. At the same time, it is also necessary for the portable device 20 to be inside the second circle C2 with the installation position of the second transmission antenna 2b as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. In other words, the radius R1 that is the signal arrival distance of the first transmission antenna 2a and the radius R2 that is the signal arrival distance of the second transmission antenna 2b are set as predetermined threshold values, respectively, and the first distance L1 is compared with the radius R1, The two distance L2 is compared with the radius R2. The first condition is that the first distance L1 is not more than the radius R1, and the second distance L2 is not more than the radius R2. Accordingly, the first condition is the first distance L1 ≦ radius R1 and the second distance L2 ≦ radius R2.

However, the region where the first circle C1 and the second circle C2 overlap includes the region indicated by cross hatching in FIG . This area corresponds to the engine room and the trunk room in the vehicle 50, and is not an area that can be said to be the vehicle interior 51. Therefore, it is necessary to delete these areas from the area where the first circle C1 and the second circle C2 overlap.

In the present invention, the second condition is added to delete these areas. And the ellipse D1 shown with the broken line in FIG. 3 was employ | adopted as the 2nd condition. Here, the ellipse D1 is an ellipse whose focal point is the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. That is, the second condition is that the portable device 20 is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as focal points.

  Generally, a law is known that an ellipse is a figure whose sum of distances from two fixed points is constant (the two fixed points are then called the focal point of the ellipse). As shown in FIG. 4, the distance between one point a1 on the circumference of the ellipse D0 and one focal point f1 of the ellipse D0 is a distance A1, and the distance between the single point a1 and the other focal point f2 of the ellipse D0 is The distance is A2. The distance between the other point b1 on the circumference of the ellipse D0 and one focus f1 of the ellipse D0 is a distance B1, and the distance between the point b1 and the other focus f2 of the ellipse D0 is a distance B2. To do. At this time, the sum of the distance A1 and the distance A2, that is, A1 + A2, is equal to the sum of the distance B1 and the distance B2, that is, B1 + B2, and the value thereof is constant. The relationship is established regardless of which point a1 and point b1 are on the ellipse D0. Expressed by the equation, A1 + A2 = B1 + B2 = K1 (constant).

  When the above-mentioned law concerning the ellipse is applied to the keyless entry system 100 of the present invention, the ellipse D1 shown in FIG. 3 corresponds to the ellipse D0 shown in FIG. 4, and the installation position of the first transmission antenna 2a is one focal point of the ellipse D0. This corresponds to f1, and the installation position of the second transmission antenna 2b corresponds to the other focal point f2 of the ellipse D0. Therefore, assuming that the ellipse D0 and the ellipse D1 have the same shape, the portable device 20 is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as the focal points, respectively. That is the second condition. In other words, the second condition is that the sum of the first distance L1 and the second distance L2, that is, the third distance L3 is L3 ≦ K1 (constant). Conversely, the fact that the portable device 20 is outside the ellipse D1 means that the third distance L3 is L3> K1 (constant). FIG. 3 shows a state where L3> K1 (constant).

As indicated by a broken line in FIG. 3 , the front side (X2 side) end of the vehicle 50 in the ellipse D1 is in contact with the front end of the windshield of the vehicle 50, and the rear side (X1) of the vehicle 50 in the ellipse D1. Side) is in contact with the rear end of the rear glass of the vehicle 50. Further, the right end (Y1 side) end of the vehicle 50 in the ellipse D1 is on the right side (Y1 side) from the right end portion of the vehicle 50, and the left end (Y2 side) end of the vehicle 50 in the ellipse D1 is the left end of the vehicle 50. On the left side (Y2 side). Accordingly, by adopting the second condition when the portable device 20 is inside the ellipse D1, an area that includes the entire interior of the vehicle interior 51 and is outside the vehicle interior in the front-rear direction of the vehicle 50, that is, the engine room of the vehicle 50. And the area corresponding to the trunk room can be deleted.

  As described above, when both the first condition and the second condition described above are satisfied, it can be determined that the portable device 20 is in the vehicle interior 51. That is, the portable device 20 is inside the first circle C1 having the signal transmission distance of the first transmission antenna 2a as the radius R1 with the installation position of the first transmission antenna 2a as the center point, and the second transmission antenna 2b. The installation position of the first transmission antenna 2b and the installation position of the second transmission antenna 2b are within the second circle C2 having the installation position as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. It can be determined that the portable device 20 is in the vehicle interior 51 when it is inside the ellipse D <b> 1 that is the focal point.

  In the keyless entry system 100, a first distance L1 that is a distance between the portable device 20 and the first transmission antenna 2a, a second distance L2 that is a distance between the portable device 20 and the second transmission antenna 2b, The third distance L3, which is the total distance of the first distance L1 and the second distance L2, is used for the inside / outside determination. As a result, although the vehicle-side transmitting antenna 2 is composed of only the first transmitting antenna 2a and the second transmitting antenna 2b, the first distance L1 and the second distance obtained by the two antennas can be reduced. No new information is required other than the 2-distance L2. Therefore, it is possible to accurately determine whether the portable device 20 is in the passenger compartment 51 or outside the passenger compartment without increasing the cost.

  Further, the keyless entry system 100 determines whether the portable device 20 is inside or outside the ellipse D1 whose focal points are the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. Added to the condition. As a result, the area outside the passenger compartment in the front-rear direction of the vehicle 50 can be removed from the area where the first circle C1 and the second circle C2 overlap, so that the portable device 20 is located in the passenger compartment 51 or outside the passenger compartment. It is easy to accurately determine whether or not

  Further, in the keyless entry system 100, the first transmission antenna 2a and the second transmission antenna 2b are installed in the vicinity of the right end of the vehicle interior 51 and the left end of the vehicle interior 51, respectively, in the center of the vehicle interior 51 in the front-rear direction. Has been. Therefore, it is possible to efficiently determine whether the portable device 20 is in the vehicle interior 51 or outside the vehicle interior using only the two vehicle-side transmission antennas 2.

  Next, the determination of the position of the portable device 20 when the portable device 20 is actually in the vehicle interior 51 or outside the vehicle compartment will be described with reference to FIGS. 5 and 6. FIG. 5 illustrates a case where the inside / outside determination of the position where the portable device 20 exists is performed for three examples (portable device 20a, portable device 20b, and portable device 20c) where the portable device 20 exists in the keyless entry system 100. It is a table. FIG. 6 is a diagram illustrating specific positions of the portable device 20a, the portable device 20b, and the portable device 20c with respect to the vehicle.

  In the table of FIG. 5, a case where the first condition or the second condition is satisfied is indicated as “◯”, and a case where the first condition or the second condition is not satisfied is indicated as “X”. In addition, in the determination result, a case where the portable device 20 exists in the vehicle interior 51 is indicated by ◯, and a case where the portable device 20 exists outside the vehicle interior is indicated by x. The first distance L1 between the portable device 20 and the installation position of the first transmission antenna 2a and the second distance L2 between the portable device 20 and the installation position of the second transmission antenna 2b are the RSSI circuit described above. It has already been obtained based on the signal strength of the request signal or the answer signal obtained by the 3a or RSSI circuit 13a. Further, the third distance L3a, which is the first distance L1 + the second distance L2, has already been obtained by the vehicle-side control unit 5 or the portable device-side control unit 15.

  In the table of FIG. 5, in the case of the portable device 20a, the first distance L1a is smaller than the radius R1 of the first circle C1, that is, L1a <R1, based on the signal strength of the request signal or the answer signal. The two distance L2a is required to be smaller than the radius R2 of the second circle C2, that is, L2a <R2. Further, the third distance L3a, which is the first distance L1a + the second distance L2a, is required to be smaller than a certain value K1 representing the shape of the ellipse D1, that is, L3a <K1. Therefore, since both the first condition and the second condition are satisfied, it can be determined that the portable device 20a is in the vehicle interior 51.

  When this result is confirmed in FIG. 6, the portable device 20a is inside the first circle C1 with the installation position of the first transmission antenna 2a as the center point and the signal arrival distance of the first transmission antenna 2a as the radius R1. At the same time, the portable device 20a is located inside the second circle C2 having the installation position of the second transmission antenna 2b as the center point and the signal arrival distance of the second transmission antenna 2b as the radius R2. Therefore, the first condition of the inside / outside determination for the portable device 20a is satisfied. Moreover, the portable device 20a is located inside an ellipse D1 that has the focal point at the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b. Therefore, the second condition of the inside / outside determination for the portable device 20a is also satisfied. Therefore, also from FIG. 6, it can be determined that the portable device 20 a exists in the vehicle interior 51. OK

  In the table of FIG. 5, in the case of the portable device 20b, similarly, the first distance L1b is smaller than the radius R1 of the first circle C1, that is, L1b <R1, and the second distance L2b is smaller than the radius R2 of the second circle C2. That is, it is required that L2b <R2. Further, the third distance L3b, which is the first distance L1b + the second distance L2b, is required to be larger than a certain value K1 representing the shape of the ellipse D1, that is, L3b> K1. Therefore, although the first condition is satisfied but the second condition is not satisfied, it can be determined that the portable device 20b is outside the passenger compartment.

  When this result is confirmed in FIG. 6, the portable device 20b is inside the first circle C1 and inside the second circle C2. Therefore, the first condition of the inside / outside determination for the portable device 20a is satisfied. However, the portable device 20b is outside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as the focal points, respectively. Therefore, the second condition for the inside / outside determination for the portable device 20b is not satisfied. Therefore, it can be determined from FIG. 6 that the portable device 20a exists outside the passenger compartment.

  In the table of FIG. 5, in the case of the portable device 20c, similarly, the first distance L1c is smaller than the radius R1 of the first circle C1, that is, L1b <R1, and the second distance L2c is larger than the radius R2 of the second circle C2. That is, it is required that L2c> R2. Further, the third distance L3c, which is the first distance L1b + the second distance L2b, is required to be smaller than a fixed value K1 representing the shape of the ellipse D1, that is, L3b <K1. Therefore, although the second condition is satisfied, the first condition is not satisfied, and therefore it can be determined that the portable device 20a is outside the passenger compartment.

  When this result is confirmed in FIG. 6, the portable device 20c is inside the ellipse D1 with the installation position of the first transmission antenna 2a and the installation position of the second transmission antenna 2b as focal points. Therefore, the second condition of the inside / outside determination for the portable device 20c is satisfied. However, the portable device 20c is inside the first circle C1, but outside the second circle C2. Therefore, the first condition of the inside / outside determination for the portable device 20c is not satisfied. Therefore, it can be determined that the portable device 20a exists outside the passenger compartment.

  As described above, the keyless entry system of the present invention has the first distance, which is the distance between the portable device and the first transmission antenna, and the second distance, which is the distance between the portable device and the second transmission antenna. And the third distance, which is the total distance of the first distance and the second distance, is used for the determination, so that although there are only two transmission antennas, two No new information is required other than the first distance and the second distance obtained by the transmitting antenna. Therefore, it is possible to accurately determine whether the portable device is inside the vehicle compartment or outside the vehicle compartment without increasing the cost.

  The present invention is not limited to the description of the above embodiment, and can be implemented with appropriate modifications in a mode in which the effect is exhibited. For example, the keyless entry system of the present invention may include components equivalent to the components shown in FIG. In the keyless entry system according to the present invention, a sedan type vehicle is used as the vehicle. However, the vehicle type may be a one-box car type or other types of vehicles, and the vehicle interior corresponding to the type may be used. Each element such as the installation position of the transmission antenna may be set by defining the shape of the transmission antenna.

DESCRIPTION OF SYMBOLS 1 Vehicle side transmission part 2 Vehicle side transmission antenna 2a 1st transmission antenna 2b 2nd transmission antenna 3 Vehicle side reception part 4 Vehicle side reception antenna 5 Vehicle side control part 6 Vehicle side oscillator 7 Vehicle side memory | storage part 8 Drive signal transmission part 10 In-vehicle device 10a In-vehicle device main body 11 Portable device side transmitting unit 12 Portable device side transmitting antenna 13 Portable device side receiving unit 14 Portable device side receiving antenna 15 Portable device side control unit 16 Portable device side oscillator 17 Portable device side storage unit 20 Portable device 50 Vehicle 51 Car interior 52 Car exterior 60 User 100 Keyless entry system L1 1st distance L2 2nd distance L3 3rd distance R1 Radius R2 Radius C1 1st circle C2 2nd circle D1 Ellipse

Claims (3)

A keyless entry system comprising an in-vehicle device provided in a vehicle and a portable device possessed by a user,
The in-vehicle device includes a vehicle-side transmission unit that transmits a request signal to the portable device, a vehicle-side transmission antenna connected to the vehicle-side transmission unit, and a vehicle-side reception unit that receives an answer signal from the portable device. A vehicle-side control unit that authenticates the answer signal and performs predetermined control,
The portable device includes a portable device-side receiving unit that receives the request signal from the vehicle-side transmitting antenna, a portable device-side transmitting unit that transmits the answer signal, a portable device-side control unit that performs predetermined control, With
The vehicle-side transmission antenna has two antennas, a first transmission antenna and a second transmission antenna, provided at predetermined positions,
The vehicle-side receiver or the portable device-side receiver has a circuit that detects the signal strength of the answer signal or the request signal,
The vehicle-side control unit or the portable device-side control unit is a first distance that is a distance between the portable device and the first transmission antenna, and a distance between the portable device and the second transmission antenna. A certain second distance is calculated based on the signal intensity,
By comparing each of the first distance, the second distance, and a third distance, which is a total distance of the first distance and the second distance, with a predetermined threshold value, the portable device is placed in the vehicle interior. A keyless entry system that determines whether the vehicle is outside or inside the passenger compartment. The portable device is
The first transmission antenna is located inside the first circle having a radius that is a first signal arrival distance in which a signal intensity transmitted from the first transmission antenna is a predetermined value or more with the installation position of the first transmission antenna as a central point; and
The second transmission antenna is located inside a second circle having a radius that is a second signal arrival distance in which a signal intensity transmitted from the second transmission antenna is a predetermined value or more with the installation position of the second transmission antenna as a center point; and
The installation position of the first transmission antenna and the installation position of the second transmission antenna are used as focal points, respectively, and the third signal arrival distance, which is the total distance of the first signal arrival distance and the second signal arrival distance, is used. When inside the ellipse
The keyless entry system according to claim 1, wherein the portable device is determined to be in the vehicle interior. The first transmission antenna and the second transmission antenna are installed at approximately the center in the front-rear direction of the vehicle interior near the right end of the vehicle interior and the left end of the vehicle interior, respectively. The keyless entry system according to claim 1 or 2.