JP2007070953A - Keyless entry device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a keyless entry device capable of positively transmitting signals to a portable unit from a vehicle side device. <P>SOLUTION: The keyless entry device has the vehicle side device 2 comprising a vehicle side transmitting part 11 having a plurality of transmitting antennas 15 provided at a vehicle to transmit request signals, and a vehicle side receiving part 10 for receiving answer signals; and the portable unit 3 comprising a portable unit receiving part 20 for receiving the request signals, and a portable unit transmitting part 21 for transmitting the answer signals. The vehicle side transmitting part 11 transmits first signals for putting the portable unit 3 in a starting state, and second signals transmitted in predetermined order and at predetermined intervals from the plurality of transmitting antennas 15 after the first signals. The vehicle side transmitting part 11 allows the transmitting antennas 15 to transmit the second signals so as to lengthen the signal length of the second signals in the order of transmission. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a keyless entry device that locks and unlocks a vehicle door by performing wireless communication between a vehicle-side device and a portable device, and more particularly, requests signals from a plurality of transmission antennas to determine the position of the portable device. It is related with the keyless entry device which transmits.

2. Description of the Related Art Conventionally, a keyless entry device that performs wireless communication between a vehicle-side device provided in a vehicle and a portable device carried by a user to lock / unlock a vehicle door is known. In recent years, when a portable device approaches the vehicle, communication is automatically performed between the vehicle-side device and the portable device. If the portable device is authenticated, a passive / locking operation is performed to lock and unlock the door of the vehicle. Keyless entry devices are also known. An example of such a keyless entry device is disclosed in Patent Document 1.
JP 2002-77972 A

  In particular, in a passive keyless entry device, it is important to be able to determine whether the portable device is outside or inside the vehicle. For this purpose, Patent Document 1 transmits a search signal including antenna identification information from the vehicle, and the portable device returns a response signal including the reception intensity data of the search signal and the antenna identification code as a response signal. Discrimination of the position of a portable device based on the above is disclosed.

  However, the conventional keyless entry device cannot be said to have sufficient reliability when detecting the signal strength. The search signal transmitted from the vehicle contains various codes such as an identification code for the antenna.If the strength of the search signal is low depending on the position of the portable device, the code cannot be read. Sometimes it cannot be identified. In addition, since signals are transmitted from a plurality of antennas, the amount of data is large, communication takes time, and power consumption is large.

  In order to solve this problem, it is conceivable that transmission timings are determined for a plurality of antennas in advance, and the portable device side determines the antennas based on the timing of received signals. In this case, it is necessary to accurately match the clock accuracy between the vehicle-side device and the portable device. However, while a crystal oscillator is generally provided on the vehicle side, a clock by CR oscillation is generally used for a portable device, so that the accuracy of the clock on the portable device is lowered.

  Therefore, if a crystal oscillator is also provided on the portable device side, the cost increases. Although it is conceivable to include a synchronization signal in each signal from the antenna, such a configuration causes a problem that the invention of Patent Document 1 has.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a keyless entry device that can accurately identify an antenna that transmits a signal from a vehicle-side device to a portable device.

In order to solve the above-described problem, a keyless entry device according to the present invention includes a vehicle-side transmission unit that is provided in a vehicle and has a plurality of transmission antennas that transmit request signals, and a vehicle-side reception unit that receives an answer signal. In a keyless entry device having a vehicle-side device, a portable device including a portable device receiver that receives the request signal, and a portable device transmitter that transmits an answer signal,
The vehicle-side transmitter transmits a first signal that activates the portable device and a second signal that is transmitted from the plurality of transmitting antennas in a predetermined order and at a predetermined interval after the first signal. ,
The vehicle-side transmission unit is configured to cause the transmission antenna to transmit so that the signal length of the second signal is increased in the order of transmission.

In the keyless entry device according to the present invention, the vehicle-side device includes a vehicle-side control unit that generates the request signal and performs various controls based on the answer signal, and the vehicle-side control unit counts the first time. A clock means,
The portable device includes a portable device control unit that generates the answer signal and performs various controls based on the request signal, and the portable device control unit includes a second clock unit that measures time,
The vehicle-side transmission unit is configured to transmit the signal length of the second signal to the transmission antenna so that the signal length of the second signal becomes longer than the error between the first clock means and the second clock means in the order of transmission. .

  Furthermore, the keyless entry device according to the present invention is configured such that the portable device control unit determines a transmission antenna at the reception timing of the second signal.

  Furthermore, the keyless entry device according to the present invention is configured such that the vehicle-side transmission unit causes the transmission antenna to transmit so that the interval between the second signals is constant.

In the keyless entry device according to the present invention, the portable device control unit is activated by the first signal to detect each strength of the second signal, and information on the detected strength is transmitted to the portable device transmission unit. Send
The vehicle-side control unit is configured to determine the position of the portable device based on the strength information received from the portable device.

  Further, in the keyless entry device according to the present invention, the portable device control unit is activated by the first signal, detects each intensity of the second signal, and the position of the portable device based on the detected intensity information. And the discrimination information is transmitted to the portable device transmission unit.

Furthermore, in the keyless entry device according to the present invention, the portable device control unit is activated by the first signal to detect the presence / absence of the second signal based on a predetermined threshold, and the information on the presence / absence of the detection is described above. Send it to the mobile device transmitter,
The vehicle-side control unit is configured to determine the position of the portable device based on detection information received from the portable device.

  Furthermore, in the keyless entry device according to the present invention, the portable device control unit is activated by the first signal, detects the presence / absence of the second signal based on a predetermined threshold, and provides information on the presence / absence of the detection. Based on this, the position of the portable device is determined, and the determination information is transmitted to the portable device transmission unit.

  In addition, a keyless entry device according to the present invention includes a vehicle-side device that includes a vehicle-side transmission unit that includes a plurality of transmission antennas provided in a vehicle and transmits a request signal, and a vehicle-side reception unit that receives an answer signal. In a keyless entry device having a portable device including a portable device receiving unit that receives the request signal and a portable device transmitting unit that transmits an answer signal, the vehicle-side transmission unit activates the portable device. A first signal and a second signal transmitted from the plurality of transmitting antennas in a predetermined order and at a predetermined interval after the first signal are transmitted, and the portable device receiving unit receives the signal in a predetermined time range. The second signal is identified as having been transmitted from one of the plurality of transmission antennas, and the second signal is respectively transmitted to the plurality of transmission antennas in the order of reception of the second signal. A control unit for identifying the one sent from the control unit, the predetermined time range, and is configured as a setting means sets sequentially longer in accordance with the reception timing.

  Furthermore, the keyless entry device according to the present invention is characterized in that the vehicle-side transmission unit sequentially sets the transmission timing of the second signal to be longer in the order of transmission.

  Furthermore, in the keyless entry device according to the present invention, the vehicle-side device includes a vehicle-side control unit that generates the request signal and performs various controls based on the answer signal. The portable device includes a portable device control unit that generates the answer signal and performs various controls based on the request signal, and the portable device control unit includes a second clock unit that measures time. The control unit sets the predetermined time range to be longer than the error between the first clock unit and the second clock unit according to the reception timing, and the vehicle-side transmission unit The signal transmission timing is set to be longer in order of transmission than the error between the first clock means and the second clock means.

  Alternatively, the keyless entry device according to the present invention is configured such that the vehicle-side transmission unit sequentially sets the signal length of the second signal to be longer in the order of transmission.

  According to the keyless entry device according to the present invention, the vehicle-side transmission unit transmits the first signal and the second signal transmitted from the plurality of transmission antennas in a predetermined order and at a predetermined interval after the first signal. The vehicle-side transmission unit causes the transmission antenna to transmit so that the signal length of the second signal is increased in the order of transmission, so that even if there is an error in the clock between the vehicle-side device and the portable device, the signal length of the second signal Are made longer in the order of transmission, the error can be absorbed, and the second signal can be reliably transmitted from the vehicle-side device to the portable device.

  Further, according to the keyless entry device according to the present invention, the vehicle-side transmission unit is provided to the transmission antenna so that the signal length of the second signal is increased by an error of the first clock means and the second clock means in order of transmission. By transmitting, the length of the second signal is increased by the error of each clock means of the vehicle side device and the portable device, so that the second signal can be reliably identified on the portable device side.

  Furthermore, according to the keyless entry device according to the present invention, the vehicle-side transmission unit can transmit the second signal efficiently by causing the transmission antenna to transmit so that the interval between the second signals is constant.

  Furthermore, according to the keyless entry device according to the present invention, the vehicle-side transmission unit transmits the first signal that activates the portable device and the plurality of transmission antennas after the first signal at predetermined intervals and at predetermined intervals. And the portable device receiver identifies the second signal received in a predetermined time range as being transmitted from one of the plurality of transmission antennas, and the second signal From the receiving order, the control unit for specifying that the second signal is transmitted from each of the plurality of transmission antennas, the control unit sequentially lengthens the predetermined time range according to the reception timing By setting, it is possible to determine the antenna that has transmitted the second signal even if there is an error in the clock between the vehicle-side device and the portable device.

  Furthermore, according to the keyless entry device according to the present invention, the vehicle-side transmission unit sets the transmission timing of the second signal to be longer in order of transmission, so that even if there is an error in the clock between the vehicle-side device and the portable device. The antenna that has transmitted the second signal can be reliably determined.

  Further, according to the keyless entry device according to the present invention, the control unit of the portable device receiving unit extends the predetermined time range by an amount greater than the error between the first clock unit and the second clock unit according to the reception timing. The vehicle-side transmission unit sets the transmission of the second signal to be longer than the error between the first clock unit and the second clock unit in order of transmission, thereby increasing the vehicle-side device and the portable device. Thus, even if there is an error in the clock, it is possible to determine the antenna that has transmitted the second signal. Also, since it is set longer in order, it takes less time than necessary.

  In addition, according to the keyless entry device according to the present invention, the vehicle-side transmission unit can easily measure the signal strength and the like by sequentially setting the signal length of the second signal to be longer in the order of transmission.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic diagram of a keyless entry device according to this embodiment. The keyless entry device according to the present embodiment locks or unlocks the door 1a of the vehicle 1. The vehicle-side device 2 is provided on the vehicle 1, the user carries the portable device 3, and the vehicle-side device. Wireless communication is performed between the mobile phone 2 and the portable device 3 to issue authentication, lock / unlock commands, and the like. The vehicle-side device 2 has a plurality of transmission antennas 15 at various locations of the vehicle 1, and a request signal is transmitted from each transmission antenna 15 to the portable device 3. The request signal is a low frequency signal.

  Hereinafter, a case where the user approaches the vehicle 1 and unlocks the door 1a will be mainly described. In the present embodiment, in order to unlock the door 1a, the user with the portable device 3 needs to press the request switch 16 provided in the vicinity of the door knob 1b of the door 1a. When the request switch 16 is pressed, communication such as authentication is performed between the vehicle side device 2 and the portable device 3, and the vehicle side device 2 unlocks the door 1a when authentication is performed.

  Next, the structure of the vehicle side apparatus 2 and the portable device 3 is demonstrated. FIG. 2 shows a configuration diagram of the vehicle-side device 2, and FIG. 3 shows a configuration diagram of the portable device 3. As shown in FIG. 2, the vehicle-side device 2 includes a vehicle-side receiver 10 that receives an answer signal from the portable device 3, a vehicle-side transmitter 11 that transmits a request signal to the portable device 3, and an answer signal. And a vehicle-side control unit 12 that performs various controls when the request switch 16 is pressed. The vehicle-side control unit 12 is configured by a CPU, and an oscillator 17 is connected to measure time. As the oscillator 17, a high-precision crystal oscillator is used. Therefore, the vehicle-side device 2 can perform highly accurate time measurement.

  In addition, the vehicle-side control unit 12 includes information necessary for control such as an 8-bit V-ID (V-ID) that is a vehicle-specific identification code and IDs of a plurality of portable devices that can operate one vehicle. Are connected to the request switch 16 described above. Furthermore, a receiving antenna 14 for receiving an answer signal is connected to the vehicle-side receiving unit 10, and a plurality of transmitting antennas 15 and 15 for transmitting a request signal are connected to the vehicle-side transmitting unit 11. The plurality of transmission antennas 15 and 15 are provided at various locations inside and outside the vehicle 1, respectively.

    As shown in FIG. 3, the portable device 3 includes a portable device receiver 20 that receives a request signal from the vehicle-side device 2, a portable device transmitter 21 that transmits an answer signal to the vehicle-side device 2, and a request. A portable device control unit 22 that performs various controls when receiving a signal, and a memory 24 that stores, for example, a 24-bit portable device ID and a V-ID in which unique values are set in the own device. ing. In addition, the portable device receiver 20 and the portable device transmitter 21 are connected to a three-axis antenna 23 having reception axes in the X, Y, and Z directions orthogonal to each other and transmitting and receiving request signals and answer signals.

  The portable device control unit 22 includes a CPU, and an oscillator 25 is connected in addition to the memory 24. The oscillator 25 on the portable device 3 side is constituted by a CR oscillation circuit. In the portable device 3, since this CR oscillation circuit is used as the oscillator 25 to measure time, the oscillation error is larger than that of the oscillator 17 provided in the vehicle side device 2. Moreover, the portable device control unit 22 switches from the sleep state in which the power consumption is substantially zero to the normal state by the wakeup signal included in the request signal from the vehicle side device 2 received by the portable device reception unit 20. The portable device control unit 22 performs various operations based on the command included in the request signal.

  FIG. 4 shows the arrangement of the reception antenna 14 and the transmission antenna 15 in the vehicle 1 and the reach of radio waves from the transmission antenna 15. One receiving antenna 14 is provided in the vehicle 1, while a plurality of transmitting antennas 15 are provided inside and outside the vehicle 1 up to the transmitting antennas 15a to 15f. In the present embodiment, three transmission antennas 15 a to 15 c are provided inside the vehicle 1, and three transmission antennas 15 d to 15 f are provided outside the vehicle 1.

  The transmission antennas 15d to 15f on the inside of the vehicle 1 are arranged so that the reach ranges of the radio waves partially overlap each other, and the three transmit antennas 15d to 15f reach the substantially entire area of the vehicle with the portable device 3 in the vehicle. Signals can be sent and received between the two. The transmitting antennas 15a to 15c outside the vehicle 1 can transmit and receive signals to and from the portable device 3 outside the vehicle by causing radio waves to reach the surroundings of the vehicle 1, respectively.

  The memory 13 of the vehicle side device 2 stores an ID necessary for authentication of the portable device 3 and data for determining the position of the portable device 3. The data for determining the position of the portable device 3 is an inner data group having a lot of data in which the intensity of the radio wave from each transmission antenna 15 and the identification code of the transmission antenna 15 are associated with each other inside and outside the vehicle 1. And the outer data group.

  Each data in the inner data group includes an identification code indicating which transmission antenna 15 is the three of the radio wave strengths from the respective transmission antennas 15 in the vicinity of the boundary line between the vehicle 1 and the outside of the vehicle 1 having the highest strength. And corresponding radio field intensity. Such data is acquired in advance over substantially the entire inner circumference of the vehicle 1. The outer data group is acquired in advance in the same manner as the inner data group over substantially the entire circumference outside the vehicle 1 and in the vicinity of the boundary line with the inside of the vehicle. The acquisition of these data is performed for the actual vehicle 1 using the portable device 3 or the strength measuring device at the time of product development. Alternatively, data can be acquired on the production line.

  When the inner data group and the outer data group are acquired, the reference space is obtained for each data group by the Mahalanobis statistical method, and the space coordinate origins on the inner side and the outer side of the vehicle 1 are calculated. This is stored in the memory 13 as data for determining the position of the portable device 3.

  When the position of the portable device 3 is determined, the portable device 3 obtains the identification code of which transmission antenna 15 and the corresponding radio wave intensity for three of the transmission antennas 15 having the highest strength. The stored data is transmitted. For the data transmitted from the portable device 3, the Mahalanobis distance from the spatial coordinate origin of the inner data group stored in the memory 13 and the Mahalanobis distance from the spatial coordinate origin of the outer data group are respectively calculated, and the Mahalanobis distance is calculated. Is determined, that is, which set is approximated, and it is determined that the portable device 3 is located there.

  Next, the operation of the keyless entry device will be described. FIG. 5 shows a flowchart of the operation when the door is unlocked. FIG. 6 shows a chart of signals transmitted from the vehicle side device 2 and the portable device 3 in the flow of FIG. FIG. 7 is a diagram illustrating an operation of determining which antenna is transmitted from which antenna in the portable device 3. The keyless entry device of the present embodiment is such that when the request switch 16 provided in the vehicle 1 is pressed, wireless communication is performed between the vehicle side device 2 and the portable device 3 and the door is unlocked. is there. Therefore, the flow starts when the user first presses the request switch 16 of the vehicle 1 (S1).

  When the request switch 16 is pressed, the vehicle-side control unit 12 causes the vehicle-side transmission unit 11 to transmit a low-frequency request signal LF1 from the transmission antenna on the driver's seat side where the possibility of the presence of the portable device is high (S2). As shown in FIG. 6, the request signal LF1 includes a signal A including a wakeup signal and a command signal CMD1. The command signal CMD1 includes V-ID (Vhicle-ID) information, which is a vehicle-specific identification code.

  When the portable device 3 receives the request signal LF1 from the portable device receiver 20, the portable device controller 22 changes from the sleep state to the normal state by the wake-up signal, and the V-ID included in the request signal LF1 is held by the portable device 3. It is determined whether or not it matches the V-ID. If the V-IDs do not match, the flow ends there. If the V-IDs match, the portable device control unit 22 causes the portable device transmission unit 21 to transmit the answer signal RF1 (S5).

  When the vehicle-side receiver 10 receives the answer signal RF1 (S6), the vehicle-side controller 12 causes the vehicle-side transmitter 11 to transmit a position confirmation signal LF2. By the way, the time from the reception of the request signal LF1 of the portable device 3 to the transmission of the answer signal RF1 is set differently depending on each portable device 3, and thus the request signal LF1 is set in the vehicle side device 2. It is possible to determine which of the plurality of portable devices has received the response by measuring the time from when the message is transmitted until the answer signal RF1 is received. Since this determination is based on only time and accuracy is poor, authentication is performed with a highly accurate, for example, 24-bit portable device ID in the following steps.

  As shown in FIG. 6, the position confirmation signal LF2 includes a wake-up signal as in the request signal LF1, and also includes a signal A including the portable device ID determined by the time, a signal including the command signal CMD2, and each transmission antenna 15a. It consists of a plurality of Rssi measurement signals transmitted in order from 15 f. At this time, the signal including the ID of the portable device and the command signal are transmitted in the signal of the transmission antenna on the driver's seat side that can receive the answer signal RF1 in the transmission of the request signal LF1. Make it.

  The signal from the control unit 12 is amplitude-modulated by the transmission unit 11 and transmitted from each of the transmission antennas 15a to 15f, but the signal from the control unit 12 for Rssi measurement has a predetermined intensity as shown in FIG. The pulse signal continues for a predetermined time, and is used for measuring the reception intensity on the portable device 3 side. Therefore, when the signal from the control unit 12 for Rssi measurement is transmitted from the antennas 15a to 15f, the signal of the carrier wave used for modulation is transmitted as it is. Each Rssi measurement signal is transmitted by the vehicle-side transmitter 11 to each of the transmission antennas 15a to 15f at a predetermined order and at a predetermined interval based on the time of the oscillator 17, so that the portable device 3 determines which transmission antenna 15 by the reception timing. It is possible to identify whether the signal is an Rssi measurement signal.

  The vehicle-side control unit 12 of the vehicle-side device 2 causes the vehicle-side transmission unit 11 to transmit the Rssi measurement signal from each transmission antenna 15 based on the timing measured from the oscillator 17. Here, the Rssi measurement signal is transmitted so as to gradually become longer in the order of transmission as shown in FIG. Note that when the transmission of the command signal CMD2 is completed on the vehicle side and reception is started on the portable device side, both timings are reset, and the timing starts after the timings of the timings are aligned. The Rssi measurement signal transmitted first is transmitted so as to have a time length of T1, and the Rssi measurement signal transmitted second is transmitted so as to have a time length of T2, which is longer than T1.

  Next, a signal to be transmitted will be specifically described. Here, n is a natural number of 2 or more. T1, T2,... T (n) indicate the length (transmission time) of the nth signal. Furthermore, the signal transmitted from each antenna on the vehicle side outputs a signal at a time interval of a fixed time Td for switching the transmission antenna, and the portable device performs analog-digital conversion (AD conversion). It is assumed that the signal needs to be continuously received at least for the time Tad. And after transmitting the command signal CMD2, the vehicle side shall switch and transmit the antenna to transmit. The actual time is the time obtained by multiplying the time of the portable device by a (a> 1).

The time Sn for completing the transmission of the nth signal from the vehicle side is
(Equation 1)
Sn = n × Td + (T1 + T2... + Tn) (Formula 1)
It becomes. Here, if the center of the time when the signal received by the portable device is determined as the nth signal is Dn,
(Equation 2)
Dn = n × Td + [T1 + T2... + T (n−1)] + Tn / 2 (Formula 2)
And
(Equation 3)
Dn + (Tad / 2) (Formula 3)
Is enough time to complete the detection. Since the clock of the portable device actually has an error, the actual time is the time represented by a × (Equation 3) (Equation 4)
a × [D n + (Tad) / 2] (Formula 4)
It becomes. And if the signal is transmitted from the vehicle for a longer time, the correct determination can be made, but in this embodiment, in order to make the minimum communication time, the actual time to complete the detection as the nth signal and the vehicle The time Sn for completing the transmission of the nth signal transmitted from is set to be the same time. And this condition is (Equation 1) = (Equation 4)
(Equation 5)
n × Td + (T1 + T2 + ・ ・ + T (n-1) + Tn)
= a × {n × Td + [T1 + T2... + T (n−1)] + Tn / 2 + (Tad / 2)} (Formula 5)
Here, the time for completing transmission of the (n−1) -th signal is expressed by the following equation.
(Equation 6)
(n−1) × Td + [T1 + T2 ++. + T (n−2) + T (n−1)]
= a × {(n−1) × Td + [T1 + T2... + T (n−2)] + T (n−1) / 2 + (Tad / 2)} (Formula 6)
Here, the right side of (Formula 6) is subtracted from the right side of (Formula 5), and the left side of (Formula 6) is subtracted from the left side of (Formula 5).
(Equation 7)
Td + Tn = a × [T (n-1) / 2 + Tn / 2 + Td] (Formula 7)
To organize this,
(Equation 8)
Tn = a / (2-a) * T (n-1) + 2 / (2-a) * (a-1) Td (Formula 8)
It becomes.
Here, when a is 1.1,
(Equation 9)
Tn = 11/9 × T (n-1) + 2/9 × Td
It becomes.
If n = 1,
(Equation 10)
Td + T1 = a (Td + T1 / 2 + Tad / 2)
And
(Equation 11)
T1 = 11/9 × Tad + 2/9 × Td
It becomes.

Next, when the actual time is the time multiplied by b (b <1) with respect to the timing of the portable device, the time Se for starting transmission of the nth signal from the vehicle side is
(Equation 12)
Se = n * Td + [T1 + T2 ... + T (n-1)] (Formula 10)
It becomes.
Here, if the center of the time when the signal received by the portable device is determined as the nth signal is Dn,
(Equation 13)
Dn = n × Td + [T1 + T2... + T (n−1)] + Tn / 2 (Formula 11)
And
(Equation 14)
Dn- (Tad / 2) (Formula 12)
Is the time required to start detection. Since the clock of the portable device actually has an error, the actual time is the time represented by b × (Expression 12) (Equation 15)
b × [D n− (Tad) / 2] (Formula 13)
It becomes. And, if the signal has been transmitted from the vehicle before that, correct determination can be made, but in this embodiment, in order to make the minimum communication time, the actual time to start detection as the nth signal, and from the vehicle The time Se for starting transmission of the nth signal to be transmitted is set to be the same time. And this condition is (Equation 10) = (Equation 13)
(Equation 16)
n × Td + [T1 + T2 + ・ ・ + T (n−1)]
= b × {n × Td + [T1 + T2... + T (n−1)] + Tn / 2− (Tad / 2)} (Formula 14)
Here, the time for starting transmission of the (n−1) -th signal is expressed by the following equation.
(Equation 17)
(n−1) × Td + [T1 + T2 ++. + T (n-2)]
= b × {(n−1) × Td + [T1 + T2... + T (n−2)] + T (n−1) / 2− (Tad / 2)} (Formula 15)
Here, the right side of (Formula 15) is subtracted from the right side of (Formula 14), and the left side of (Formula 15) is subtracted from the left side of (Formula 14).
(Equation 18)
Td + T (n-1) = b × [Td + T (n-1) / 2 + Tn / 2] (Formula 16)
When organized (Equation 19)
Tn = (2−b) / bT (n−1) + 2 / b × (1-b) × Td (Formula 17)
Where b = 0.9
(Equation 20)
T1 = 11/9 × Tad + 2/9 × Td
Which is consistent with (Equation 9). From this, it can be seen that both equations agree when a + b = 2 when calculated assuming that (Equation 8) = (Equation 17).
Actually, the reception start and end times on the portable device side are not set, but only the reception start is set, and the reception is automatically stopped when the AD conversion is completed.

  Table 1 shows an example in the case where the setting is specifically made with Tad = 2 msec and Td = 0.4 msec based on the calculation result. As is apparent from this table, even if the clock of the portable device is shifted, when the portable device determines that it is the nth transmission signal, it is sufficient to recognize the vehicle's nth signal and simultaneously perform AD conversion. In time, the portable device can receive the signal and can therefore determine.

  In the first embodiment, a + b = 2 is set, but other values may be used. In this case, the equation may be obtained in the same manner. In the first embodiment, the signal length is a value calculated by one formula obtained by adding a predetermined value to a constant multiple of the length of the previous signal, but it is not always necessary to do so. That is, some time may be added as a margin to the value obtained by the equation in the first embodiment. Although Td is also constant, it is not always necessary to do this. Furthermore, the set time at which the portable device starts reception does not necessarily have to be a value expressed by a predetermined mathematical formula, and even if the clock of the portable device is shifted, the portable device can determine that it is the nth transmission signal. At the same time, it is sufficient to set the time when the portable device can receive the signal for a time sufficient for AD conversion of the nth signal of the vehicle.

Next, a second embodiment will be described. In the second embodiment, values are calculated in order from given numerical values. Clock shift The same as in the first embodiment. Specifically, in the second embodiment, the transmission start time T1f of the first signal transmitted from the vehicle side is transmitted after Td (0.4 msec) required for antenna switching. Since the start of reception of the portable device needs to be within the period in which the signal from the vehicle is transmitted, no matter how the clock is shifted, the set value for the start of reception is T1f / 0 .9 must be set. In addition, the end of transmission of the signal transmitted from the vehicle requires that the signal be transmitted from the vehicle for a time sufficient for reception during the Tad (2 msec) even if the clock of the portable device is shifted. There is. Then, it is only necessary to obtain a condition for receiving during Tad (2 msec) when the actual reception start time of the portable device is the most delayed (set value of portable device) × 1.1 + Tad. Then, after this time Td (0.4 msec), set the next signal to be transmitted from the vehicle, and similarly determine the set time for starting reception of the portable device and the end time of the signal transmitted from the vehicle. It ’s fine. The results obtained in this way are shown in Table 2. As is apparent from Table 2, even if the clock of the portable device is shifted, when the portable device determines that it is the nth transmission signal, the portable device has sufficient time to AD convert the nth signal of the vehicle. The machine can receive the signal, and therefore can correctly determine that it is a transmission signal from a predetermined antenna.
In the second embodiment, as in the first embodiment, some time may be added as a margin to the obtained value. Although Td is also constant, it is not always necessary to do this.

  In the first and second embodiments, the reason why the signal is lengthened sequentially as compared with the immediately preceding signal is to shorten the total communication time by increasing the signal according to the shift of the clock. For example, T10 This is because the communication time is reduced compared to the case where a signal having a length of 1 is transmitted from all antennas and the reception start setting value of the portable device is devised. However, for example, the signal length of T1 may be increased according to T2 or T4. In short, the total communication time is shortened compared to the transmission with the longest signal, and the signal length of all or most of the signals becomes longer according to the clock shift, and even if the clock of the portable device shifts, When the machine determines that it is the nth transmission signal, it can be recognized as the nth signal of the vehicle, and a signal is transmitted from the vehicle so that it can be received for a time sufficient to perform a predetermined operation such as AD conversion It only has to come to be done.

  The position confirmation signal LF2 including the Rssi measurement signal transmitted from each of the transmission antennas 15a to 15f is received by the portable device receiver 20 of the portable device 3 (S8). The portable device control unit 22 measures the strength of each Rssi measurement signal as described above, and for the three pieces of data from the strongest one, the identification code indicating which transmission antenna 15 is associated with the corresponding strength data, Is transmitted to the vehicle side apparatus 2 as an answer signal RF2 (S9). At this time, the answer signal RF2 is also transmitted including the ID of the portable device which is an ID uniquely set for each portable device. The signal strength measurement is not limited to measuring the strength on the portable device 3 side by transmitting an Rssi measurement signal from the vehicle 1 side, but the strength of the request signal itself transmitted from the vehicle 1 side. You may measure. However, in the case of a request signal, it is a signal indicating a predetermined code, and the RSSI value changes depending on the code, so the accuracy cannot be improved. However, in this embodiment, the accuracy is improved because it is a constant signal.

  The Rssi measurement signals transmitted from the transmission antennas 15a to 15f are transmitted in a predetermined order and at predetermined intervals, and the mobile device 3 identifies the transmission antenna 15 based on the reception timing. Therefore, the wake-up signal is included in each Rssi measurement signal. And a command signal need not be included, the amount of data can be reduced to reduce the time required for communication, and the power consumption can be reduced. Further, even in a weak radio wave state where the wake-up signal or command signal cannot be recognized depending on the position of the portable device 3, it is possible to reliably identify which transmission antenna 15 is the signal transmitted from the reception timing.

  The vehicle side transmitter 11 of the vehicle side device 2 receives the answer signal RF2 from the portable device 3 (S10). When the answer signal RF2 is received, the vehicle-side control unit 12 determines whether or not the ID of the portable device included therein matches with that registered in the vehicle (S11). Here, if the ID of the portable device does not match that registered in the vehicle, the flow is ended there and the same operation is performed on the next portable device. On the other hand, if the ID of the portable device matches that registered in the vehicle, then the position of the portable device 3 is determined (S12).

  As described above, the position of the portable device 3 is determined by the identification code and the intensity data included in the answer signal RF2 transmitted from the portable device 3, and the spatial coordinate origin and the outer data group of the inner data group stored in the memory 13. The Mahalanobis distance to the origin of the spatial coordinates of the inner data group is calculated, and the portable device 3 is in the vehicle 1 if it is close to the spatial coordinate origin of the inner data group. It is determined that there is something.

  Thereafter, the vehicle-side controller 12 performs different control depending on whether the portable device 3 is inside the vehicle 1 or outside the vehicle 1 (S13). When it is determined that the position of the portable device 3 is not outside the vehicle 1, that is, the portable device 3 is inside the vehicle 1, the flow is finished as it is.

  When the request switch 16 is pressed to unlock the door, the portable device 3 should be outside the vehicle 1, and if the door is unlocked when the portable device 3 is inside the vehicle 1 together with the user, Even a person who does not have the machine 3 can push the request switch 16 to unlock the door. In order to prevent this, when the portable device 3 is in the vehicle 1, the door is not unlocked.

  On the other hand, when it is determined that the position of the portable device 3 is outside the vehicle 1, an unlock command signal is output to the door locking device (not shown) to unlock the door (S14). Since the position of the portable device 3 is determined by calculating the Mahalanobis distance from the inner data group and the outer data group, the position determination can be performed with high accuracy, and unlock malfunctions can be reduced.

Here, the operation of pressing the request switch 16 to unlock the door is shown, but the operation of locking the door can be similarly determined by determining the position of the portable device 3 and performing control according to the result. Further, not only the door locking / unlocking operation, but also the operation of starting the engine according to the position of the portable device 3, the position of the portable device 3 is similarly determined, and the operation is performed according to the result. be able to.
By the way, although the case where the request signal LF1 is transmitted from the transmitting antenna on the driver's seat side and the answer signal RF1 can be received in the above-described S2 has been mentioned, if this is not possible, the transmitting antenna with the next highest priority (for example, the frequency of existence is high). Or the presence frequency is high in consideration of predetermined conditions such as lock and unlock), and similarly, an antenna that can be received by the portable device 3 is specified, and in the subsequent transmission of LF2, a wake-up signal is transmitted. Determine the antenna to transmit.

  If the ID of the portable device 3 cannot be authenticated in the transmission of LF2, then the signal is switched by switching the antenna that transmits the wake-up signal and the ID of the portable device 3 to the antenna having the highest priority, for example, the center of the vehicle. Switch antennas until transmission is successful. If authentication is not possible even in such a manner, for the portable devices with higher priority among the remaining portable devices (priority is determined by the frequency of use within a predetermined period, for example), The antenna that transmits the wake-up signal and the ID of the portable device 3 is switched in the order of the antenna specified by transmission and the antenna having the highest priority. Further, if this still fails, the same procedure is performed for other portable devices. By the way, if the ID of the portable device is included in LF2 as described above, it will take a very long time if it cannot be authenticated. Therefore, it is also possible to perform authentication separately without including the ID of the portable device in the LF2 signal. good.

Also, for example, if LF1 could not be specified, include the wake-up signal and portable device ID in the transmission signals from all antennas, or include in the transmission signals from multiple antennas with high priority Deformation is possible.
In addition, it is not always necessary to specify the antenna that can be received by transmitting LF1 and the portable device. One antenna having a high priority order or a plurality of antennas that are not all antennas include a wake-up signal. You may make it authenticate separately by machine ID.

  Next, a third embodiment will be described. The first and second embodiments are examples in which the length of the signal transmitted from the vehicle side is sequentially increased. In the third embodiment, the signal length is constant as shown in FIG. In order to be able to determine that the signal is transmitted from a specific antenna even when the clock of the machine is shifted, the time for determining that the signal is transmitted from a specific antenna is extended and adjusted accordingly. The signal interval of signals transmitted from the vehicle is extended. Although not shown for equations or numerical examples, as shown in FIG. 8, the nth signal is also obtained when the clock is shifted and the actual time is the shortest, and when the clock is shifted and the actual time is the longest. Each value is set so that it can be recognized as the nth signal. This embodiment may be an RSSI detection signal as in the above embodiment, but it is also possible to specify from which antenna a signal having predetermined information such as a non-uniform code is transmitted.

  Although the embodiment of the present invention has been described above, the application of the present invention is not limited to this embodiment, and can be applied in various ways within the scope of its technical idea. For example, in the present embodiment, as shown in FIG. 4, three transmission antennas 15 are provided inside and outside the vehicle 1, but the number and arrangement of the transmission antennas 15 are not limited to this. One or more are enough. However, the position of the plurality of transmission antennas 15 can be determined with higher accuracy. Further, in the present embodiment, three are selected from those having a high reception intensity from the transmission antenna 15 and are used for position determination as data, but this is not limited to three, and all data is used. May be.

  Further, in the present embodiment, the vehicle-side control unit 12 on the vehicle-side device 2 side calculates the Mahalanobis distance between the data from the portable device 3 and the inner data group and the outer data group. The spatial coordinate origin of the inner data group and the outer data group is stored and the Mahalanobis distance is calculated by the portable device control unit 22 to determine the position of the portable device 3. Good.

  Furthermore, the data stored in the memory 13 may be the inner data group and the outer data group instead of the spatial coordinate origin as in the present embodiment. In this case, the position determination of the portable device 3 may be performed. In this case, the spatial coordinate origin and the Mahalanobis distance are calculated. The position discrimination method is not limited to the method for calculating the Mahalanobis distance as in this embodiment, and a linear discriminant may be used. However, the position determination can be performed with higher accuracy by using the Mahalanobis distance.

  In the present embodiment, the portable device 3 measures the strength of a plurality of Rssi measurement signals and determines the position of the portable device 3 based on the measured Rssi measurement signals. You may make it perform the position determination of the portable device 3 based on the presence or absence of reception. At this time, a predetermined threshold is set for the intensity of the Rssi measurement signal, and when the intensity greater than the threshold is detected, it is determined that the Rssi measurement signal has been received. Otherwise, the Rssi measurement signal is used. It is determined that no signal has been received.

  Further, when detecting the presence / absence of an Rssi measurement signal, the mobile device 3 does not determine the position, but transmits the signal presence / absence information from the mobile device 3 to the vehicle-side device 2 and receives the information. The position of the portable device 3 may be determined by the vehicle-side control unit 12 of the vehicle-side device 2.

It is a schematic diagram of the keyless entry device in this embodiment. It is a block diagram of a vehicle side device. It is a block diagram of a portable machine. It is the figure which showed the position of the transmission antenna provided in a vehicle, and the reach | attainment range of an electromagnetic wave. It is a flowchart in the case of unlocking operation. It is a chart figure of the signal from a vehicle side apparatus and a portable machine. It is a figure which shows a 1st Example. It is a figure which shows a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Vehicle side apparatus 3 Portable machine 10 Vehicle side receiving part 11 Vehicle side transmission part 12 Vehicle side control part 13 Memory 14 Reception antenna 15 Transmission antenna 16 Request switch 20 Portable machine receiving part 21 Portable machine transmission part 22 Portable machine control part 23 Triaxial antenna

Claims (12)

A vehicle-side device including a vehicle-side transmitter having a plurality of transmission antennas provided in the vehicle and transmitting a request signal, a vehicle-side receiver that receives an answer signal, and a portable device receiver that receives the request signal In a keyless entry device having a portable device equipped with a portable device transmitter for transmitting an answer signal,
The vehicle-side transmitter transmits a first signal that activates the portable device and a second signal that is transmitted from the plurality of transmitting antennas in a predetermined order and at a predetermined interval after the first signal. ,
The keyless entry device, wherein the vehicle-side transmission unit causes the transmission antenna to transmit so that the signal length of the second signal is increased in order of transmission. The vehicle-side device includes a vehicle-side control unit that generates the request signal and performs various controls based on the answer signal, and the vehicle-side control unit includes a first clock unit that measures time,
The portable device includes a portable device control unit that generates the answer signal and performs various controls based on the request signal, and the portable device control unit includes a second clock unit that measures time,
2. The vehicle-side transmitter unit transmits the second signal to the transmitting antenna so that the signal length of the second signal becomes longer than the error between the first clock means and the second clock means in the order of transmission. The keyless entry device described.   3. The keyless entry device according to claim 2, wherein the portable device control unit discriminates a transmission antenna at a reception timing of the second signal.   The keyless entry device according to any one of claims 1 to 3, wherein the vehicle-side transmission unit causes the transmission antenna to transmit so that an interval between the second signals is constant. The portable device control unit is activated by the first signal and detects each intensity of the second signal, and transmits the detected intensity information to the portable device transmission unit,
The keyless entry device according to any one of claims 1 to 4, wherein the vehicle-side control unit determines the position of the portable device based on the strength information received from the portable device.   The portable device control unit is activated by the first signal, detects each intensity of the second signal, determines the position of the portable device based on the detected intensity information, and uses the determination information as the portable information. The keyless entry device according to claim 1, wherein the keyless entry device is transmitted to a machine transmitter. The portable device control unit is activated by the first signal and detects the presence / absence of the second signal based on a predetermined threshold, and transmits information on the presence / absence of detection to the portable device transmission unit,
The keyless entry device according to any one of claims 1 to 4, wherein the vehicle-side control unit determines the position of the portable device based on detection information received from the portable device.   The portable device control unit is activated by the first signal, detects the presence / absence of the second signal based on a predetermined threshold, determines the position of the portable device based on the presence / absence of the detection, and The keyless entry device according to claim 1, wherein the discrimination information is transmitted to the portable device transmission unit. A vehicle-side device including a vehicle-side transmitter having a plurality of transmission antennas provided in the vehicle and transmitting a request signal, a vehicle-side receiver that receives an answer signal, and a portable device receiver that receives the request signal In a keyless entry device having a portable device equipped with a portable device transmitter for transmitting an answer signal,
The vehicle-side transmitter transmits a first signal that activates the portable device and a second signal that is transmitted from the plurality of transmitting antennas in a predetermined order and at a predetermined interval after the first signal. ,
The portable device reception unit identifies the second signal received in a predetermined time range as being transmitted from one of the plurality of transmission antennas, and determines the second signal from the reception order of the second signal. Each of the signals is transmitted from the plurality of transmission antennas, and the control unit sequentially sets the predetermined time range to be longer according to the reception timing. Keyless entry device.   The keyless entry device according to claim 9, wherein the vehicle-side transmitter sets the transmission timing of the second signal longer in order of transmission. The vehicle-side device includes a vehicle-side control unit that generates the request signal and performs various controls based on the answer signal, and the vehicle-side control unit includes a first clock unit that measures time,
The portable device includes a portable device control unit that generates the answer signal and performs various controls based on the request signal, and the portable device control unit includes a second clock unit that measures time,
The control unit sets the predetermined time range to be longer than the error between the first clock unit and the second clock unit according to the reception timing, and the vehicle-side transmission unit transmits the second signal. 11. The keyless entry device according to claim 10, wherein the transmission timing is sequentially set to be longer than the error between the first clock means and the second clock means in order of transmission. 10. The keyless entry device according to claim 9, wherein the vehicle-side transmission unit sets the signal length of the second signal to be longer in order of transmission.

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