JP5918101B2 - Key position determination device - Google Patents

Description

  The present invention relates to a key position determination device that determines whether a vehicle key is located outside or inside a vehicle interior.

  In Patent Document 1, the position of the vehicle key is determined while performing two-way communication between the vehicle key and the vehicle-mounted device, and when the vehicle key is in the communication area outside the passenger compartment, the door lock is allowed to be unlocked and unlocked. In addition, a technique is disclosed that allows the engine to be started when the vehicle key is in a communication area in the passenger compartment.

JP 2002-029385 A (paragraph [0002] to paragraph [0008])

  However, when a call signal to be transmitted to the communication area inside the vehicle interior is also transmitted to the communication area outside the vehicle interior, when there is a vehicle key in the communication area outside the vehicle interior, a response signal is transmitted from this vehicle key, In this case, the engine can be started despite the vehicle key being outside the passenger compartment.

  On the other hand, when a call signal to be transmitted to the communication area outside the vehicle compartment is also transmitted to the communication area inside the vehicle interior, when there is a vehicle key in the communication area inside the vehicle interior, a response signal is transmitted from this vehicle key, In this case, although the vehicle key is in the vehicle compartment, the door lock is allowed to be locked and there is a risk of in-lock.

  In addition, while using an impulse UWB (Ultra Wide Band) radio wave as an interrogation signal or a response signal, the distance to the vehicle key is measured based on the time from when the interrogation signal is transmitted until the response signal is received. Although it is conceivable to determine the position of the key, in this case, the same problem as described above occurs due to an error in distance measurement.

  The present invention has been made paying attention to such problems, and an object thereof is to provide a key position determination device capable of accurately determining the position of a vehicle key.

  In order to solve the above-described problem, a key position determination device that determines whether the vehicle key is located outside or inside the vehicle interior receives a call signal from the vehicle-mounted device, and the vehicle key is located in the transmission area of the call signal. When the number of reflected waves following the direct wave of the response signal exceeds a threshold value, it is determined that the vehicle key is in the vehicle compartment, assuming that a response signal to the call signal is transmitted from the vehicle key. The gist of the invention is that it includes a determination unit that determines that the vehicle key is outside the passenger compartment when the number of reflected waves is equal to or less than the threshold value.

  According to this configuration, since the vehicle interior is a space surrounded by a metal body such as a vehicle body, there are many reflected waves, and differentiation from the outside of the vehicle interior with few reflected waves is achieved. As a result, the inside / outside of the vehicle can be distinguished with high accuracy. Therefore, the position of the vehicle key can be accurately determined.

  For the key position determination device, the vehicle-mounted device measures the distance from the own device to the vehicle key based on a response time defined as a time from when the call signal is transmitted to when the response signal is received. The determination means determines the position of the vehicle key based on the number of reflected waves when the distance measured by the vehicle-mounted device is a distance that suggests that the vehicle key is near the boundary between the vehicle interior and exterior. It may be determined.

According to this configuration, it is possible to accurately determine the position of the vehicle key at a position where it is difficult to determine whether the vehicle is inside or outside due to a distance measurement error.
With respect to the key position determining device, the vehicle-mounted device is provided on the pillar or on the ceiling or window glass, which is defined as a place where a response signal from the vehicle key directly reaches, assuming that the vehicle key is outside the vehicle compartment. It is good.

  According to this configuration, the number of reflected waves received by the vehicle-mounted device is positively differentiated between when the vehicle key is in the vehicle interior and when it is outside the vehicle interior. Can be increased.

  According to the present invention, the position of the vehicle key can be accurately determined.

The block diagram which shows the structure of an electronic key system. The conceptual diagram which shows operation | movement when determining the position of a vehicle key.

Hereinafter, an embodiment of a key position determination device will be described.
As shown in FIG. 1, an electronic key system 1 as an example of a key position determination device includes a vehicle key 2 possessed by a vehicle owner and a vehicle-side security device 3. The vehicle key 2 is called a portable device because of its possession.

  The vehicle key 2 includes a communication antenna 21, a communication circuit 22, and a microcomputer 23. The communication antenna 21 is a medium for receiving an interrogation signal transmitted from the security device 3 and also a medium for transmitting a response signal to the interrogation signal. Both the interrogation signal and the response signal in this example are defined as UWB radio waves with an impulse waveform of 3.1 to 10.25 GHz. The communication circuit 22 generates a reception signal while electrically processing the interrogation signal received by the communication antenna 21, and outputs this reception signal to the microcomputer 23. The microcomputer 23 includes a nonvolatile memory 23a, and an ID unique to the vehicle key 2 is stored in the memory 23a. When the reception signal related to the challenge signal is input from the communication circuit 22, the microcomputer 23 generates an original signal including the ID in order to respond to the challenge signal, and outputs the original signal to the communication circuit 22. The communication circuit 22 generates a response signal while electrically processing the original signal input from the microcomputer 23, and transmits this response signal from the communication antenna 21.

  The security device 3 includes a transceiver 31 and a verification ECU (Electronic Control Unit) 32. There are three transceivers 31 in this example, the first is on the upper part of the A-pillar on the driver's seat side, the second is on the upper part of the A-pillar on the passenger side, and the third is on the ceiling at the rear of the vehicle. Is provided. Each place is defined as a place where a response signal from the vehicle key 2 directly arrives on the assumption that the vehicle key 2 exists outside the passenger compartment. Each transceiver 31 generates an interrogation signal while electrically processing the original signal input from the verification ECU 32, and transmits the interrogation signal. Each transceiver 31 generates a reception signal while electrically processing a response signal from the vehicle key 2, and outputs the reception signal to the verification ECU 32. Each transceiver 31 measures the distance from its own device to the vehicle key 2 based on the response time defined as the time from the transmission of the interrogation signal to the reception of the response signal, and compares the distance measurement result with the verification ECU 32. Output to.

  The verification ECU 32 includes a non-volatile memory 32a, and the ID of the regular vehicle key 2 that is suitable for the host vehicle is registered as a reference ID in the memory 32a. When the reception signal related to the response signal is input from the transceiver 31, the verification ECU 32 verifies the ID included therein with the reference ID. The verification ECU 32 permits the lock / unlock of the door lock and the start of the engine through the determination of the key position based on the measurement result of the distance on the condition that the ID matches.

Next, the operation of the electronic key system 1 will be described.
As shown in FIG. 2, each transceiver 31 measures the distance from its own device to the vehicle key 2 based on the time from transmission of the interrogation signal until reception of the response signal, and collates the distance measurement results. It outputs to ECU32. Since this measurement result includes an error of about 30 cm due to sampling time, multipath, temperature characteristics, and the like, for example, when the vehicle key 2 is near the door (near the boundary outside the vehicle interior), conventionally, the vehicle interior It was difficult to distinguish outside.

  When the distance measured by each transceiver 31 is a distance at which the vehicle key 2 can be determined to be inside the vehicle compartment or outside the vehicle compartment even if the measurement error is taken into account, the verification ECU 32 of this example performs measurement by each transceiver 31. Based on the result, the key position is determined. In this case, the collation ECU 32 permits the door lock to be unlocked when it is determined that the vehicle key 2 is outside the vehicle compartment, and permits the engine start when it is determined that the vehicle key 2 is inside the vehicle interior.

  When the distance measured by each transceiver 31 is a distance that makes it difficult to discriminate between the interior and exterior of the vehicle when the measurement error is taken into account, the verification ECU 32 analyzes the received signal from the transceiver 31 and directly outputs the response signal. The position of the vehicle key 2 is determined based on the number of reflected waves following the wave. If the vehicle key 2 is outside the passenger compartment, the number of reflected waves is small. In this example, after a direct wave is detected at the point P1, no reflected wave is detected. On the other hand, when the vehicle key 2 is in the passenger compartment, several reflected waves exceeding a predetermined level are detected after a direct wave is detected at the point P1. This is because the vehicle interior is a space surrounded by a metal body such as a vehicle body. When the number of reflected waves exceeds a threshold value (for example, two), the verification ECU 32 determines that the vehicle key 2 is in the vehicle interior. When the number of reflected waves is equal to or less than the threshold value, the vehicle key 2 is outside the vehicle interior. Is determined.

As described above, according to the present embodiment, the following effects can be obtained.
(1) Since the interior of the vehicle is a space surrounded by a metal body, there are many reflected waves, and the vehicle interior can be differentiated from the outside of the vehicle with less reflected waves. As a result, the inside / outside of the vehicle can be distinguished with high accuracy. Therefore, the position of the vehicle key 2 can be accurately determined.

  (2) When the distance measured by each transceiver 31 is a distance that suggests that the vehicle key 2 is in the vicinity of the boundary inside and outside the vehicle interior, the position of the vehicle key 2 is determined based on the number of reflected waves. The Therefore, it is possible to accurately determine the position of the vehicle key 2 at a position where it is difficult to determine whether the vehicle is inside or outside due to an error in distance measurement.

  (3) Each transceiver 31 is provided on the upper or rear ceiling of the pillar, which is defined as a place where a response signal from the vehicle key 2 directly reaches, on the assumption that the vehicle key 2 is outside the passenger compartment. In this way, the number of reflected waves received by the transceiver 31 is positively differentiated between when the vehicle key 2 is in the vehicle interior and when it is outside the vehicle interior, thereby increasing the accuracy of determination inside and outside the vehicle interior. be able to.

In addition, the said embodiment can also be changed and actualized as follows.
The antenna of the transceiver 31 may be provided on the window glass. Also in this case, on the assumption that the vehicle key 2 is outside the vehicle compartment, the response signal from the vehicle key 2 reaches the antenna directly. The antenna may be provided not only on the ceiling at the rear of the vehicle according to the above embodiment, but also on the ceiling at the center of the vehicle or the ceiling at the front of the vehicle. In either case, an antenna may be provided at a position on the right side or a position on the left side. By providing the antenna on the ceiling, a response signal from the vehicle key 2 outside the passenger compartment reaches the antenna directly.

The measurement of the number of reflected waves may be aborted while determining that the vehicle key 2 is in the passenger compartment when the number of reflected waves exceeds the threshold.
Regardless of the distance measurement result by each transceiver 31, the number of reflected waves may be measured, and the position of the vehicle key 2 may be determined based on the distance measurement result and the number of reflected waves.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
(A) In the key position determination device, the vehicle-mounted device measures the distance from its own device to the vehicle key based on the response time from when the call signal is transmitted until the direct wave of the response signal is received.

  (B) In the key position determination device, the determination means is based on the number of reflected waves only when the distance measured by the vehicle-mounted device is a distance that suggests that the vehicle key is near the boundary between the vehicle interior and exterior. To determine the position of the vehicle key.

  DESCRIPTION OF SYMBOLS 1 ... Electronic key system (key position determination apparatus), 2 ... Vehicle key (vehicle key), 3 ... Security device, 21 ... Communication antenna, 22 ... Communication circuit, 23 ... Microcomputer, 23a ... Memory, 31 ... Transceiver (vehicle equipment ), 32... Verification ECU (determination means), 32 a.

Claims (3)

In a key position determination device for determining whether the vehicle key is located outside or inside the vehicle interior,
When an interrogation signal is transmitted from the vehicle-mounted device and a vehicle key exists in the transmission area of the interrogation signal, the reflection following the direct wave of the response signal is assumed on the assumption that a response signal to the interrogation signal is transmitted from the vehicle key. When the number of waves exceeds a threshold, the vehicle key is determined to be inside the vehicle interior, and when the number of reflected waves is equal to or less than the threshold, determination means is provided to determine that the vehicle key is outside the vehicle interior. A key position determination device. The on-vehicle device measures the distance from the own device to the vehicle key based on the response time defined as the time from when the call signal is transmitted to when the response signal is received,
The determination means determines the position of the vehicle key based on the number of reflected waves when the distance measured by the vehicle-mounted device is a distance that suggests that the vehicle key is near the boundary between the vehicle interior and exterior. The key position determination device according to claim 1. 3. The vehicle-mounted device is provided on a pillar upper portion, a ceiling, or a window glass that is defined as a place where a response signal from the vehicle key directly reaches, assuming that a vehicle key is provided outside the vehicle compartment. Key position determination device.