JP7600715B2 - In-vehicle device and vehicle system - Google Patents

Description

This disclosure relates to an in-vehicle device and a vehicle system.

Technology is known that uses radio waves transmitted and received between an in-vehicle device and a mobile terminal to determine the positional relationship of the mobile terminal with respect to the vehicle. For example, Patent Document 1 discloses technology in which an in-vehicle system estimates the distance of a mobile terminal from the vehicle based on the time (hereinafter, round trip time) between transmitting an impulse signal used in UWB (Ultra Wide Band) communication and receiving a response signal from the mobile terminal. UWB communication is known as ultra-wideband wireless communication.

JP 2018-91071 A

When estimating the distance of a mobile terminal from a vehicle using UWB communication, as in the technology disclosed in Patent Document 1, the distance of a mobile terminal outside the vehicle cabin may be erroneously estimated as being farther away due to radio wave shielding by human bodies, etc., and the effects of multipath. In this case, the position of the mobile terminal outside the vehicle cabin will be erroneously determined to be farther away from the vehicle.

One objective of this disclosure is to provide an in-vehicle device and a vehicle system that enable more accurate determination of the position of a mobile terminal outside the vehicle cabin, even when ultra-wideband wireless communication is used to determine the position of the mobile terminal relative to the vehicle.

The above object is achieved by a combination of features recited in the independent claims, and the subclaims define further advantageous embodiments of the disclosure. The reference characters in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure.

In order to achieve the above object, the in-vehicle device of the present disclosure is an in-vehicle device that is used in a vehicle and includes a terminal distance estimation unit (305) that estimates a terminal distance, which is a distance of a mobile terminal from an antenna, based on an impulse signal that can be transmitted and received by ultra-wideband wireless communication between a mobile terminal carried by a user and an antenna (32) provided in the vehicle, and the terminal distance estimation unit estimates the terminal distance for each of interior and exterior antennas (32a, 32b, 32c, 32d, 32e, 32f), which are three or more antennas including an indoor antenna (32e, 32f) provided in the cabin of the vehicle and an exterior antenna (32a, 32b, 32c, 32d) provided outside the cabin of the vehicle, and among the interior and exterior antennas, an interior and exterior antenna (32a, 32b, 32c, 32d) having a shorter terminal distance estimated by the terminal distance estimation unit is selected. The vehicle is provided with a selection unit (306, 306a) which selects at least two antennas less than the total number of antennas, and a terminal position determination unit (307, 307a) which determines the position of the mobile terminal relative to the vehicle by using the terminal distance for the antenna selected by the selection unit among the terminal distances estimated by the terminal distance estimation unit, and the selection unit (306) selects two antennas from the inside and outside antennas which have a shorter terminal distance estimated by the terminal distance estimation unit, and the terminal position determination unit (307) determines the position of the mobile terminal relative to the vehicle by narrowing down two candidate points for the position of the mobile terminal relative to the vehicle, which are determined from the terminal distances for the two antennas selected by the selection unit among the terminal distances estimated by the terminal distance estimation unit, to one based on which antenna has the shorter terminal distance .

When the mobile terminal is located outside the vehicle cabin, the terminal distance, which is the distance from the antenna to the mobile terminal estimated by the terminal distance estimation unit based on the impulse signal transmitted and received by ultra-wideband wireless communication, may be erroneously estimated as a longer distance than the actual distance due to the effects of radio wave shielding by a human body, etc., and multipath. In contrast, with the above configuration, at least two antennas, less than the total number of interior and exterior antennas, that have a shorter estimated terminal distance are selected from among the three or more interior and exterior antennas including the indoor antenna and the exterior antenna, and the position of the mobile terminal relative to the vehicle is determined using the terminal distance for the selected antenna. When the terminal distance is erroneously estimated, it is erroneously estimated as a longer distance than the actual distance, so the shorter the estimated terminal distance, the lower the possibility that the estimated terminal distance is erroneous. Therefore, even if the terminal distance of a mobile terminal located outside the vehicle cabin is erroneously estimated, it is possible to exclude the terminal distance that is likely to be erroneously estimated and determine the position of the mobile terminal relative to the vehicle using a more accurate terminal distance. As a result, even when the position of the mobile terminal relative to the vehicle is determined using ultra-wideband wireless communication, it is possible to more accurately determine the position of the mobile terminal outside the vehicle cabin.

To achieve the above object, the vehicle system of the present disclosure includes a mobile terminal (2) used in a vehicle and carried by a user, three or more antennas including an indoor antenna (32e, 32f) provided inside the vehicle cabin and an outdoor antenna (32a, 32b, 32c, 32d, 32e, 32f) provided outside the vehicle cabin, and the above-mentioned on-board device (30, 30a).

As a result, since the in-vehicle device described above is included, it becomes possible to determine the position of a mobile terminal outside the vehicle with greater accuracy, even when ultra-wideband wireless communication is used to determine the position of the mobile terminal relative to the vehicle.

1 is a diagram illustrating an example of a schematic configuration of a vehicle system 1. FIG. FIG. 2 is a diagram showing an example of a schematic configuration of a portable terminal 2. 2 is a diagram showing an example of a schematic configuration of a vehicle-side unit 3 and a communication ECU 30. FIG. FIG. 2 is a diagram showing an example of an arrangement of UWB anchors 32 (32a to 32f). 11A and 11B are diagrams for explaining an example of narrowing down terminal positions from two candidate points in the first embodiment. 10 is a flowchart showing an example of a flow of a mobile terminal position determination related process in a communication ECU 30. FIG. 1 is a diagram for explaining the effects of the configuration of the first embodiment. FIG. 1 is a diagram for explaining the effects of the configuration of the first embodiment. FIG. 2 is a diagram showing an example of a schematic configuration of a communication ECU 30a.

Several embodiments for disclosure will be described with reference to the drawings. For ease of explanation, parts in several embodiments that have the same functions as parts shown in the drawings used in the previous explanations may be given the same reference numerals and their explanations may be omitted. For parts given the same reference numerals, the explanations in other embodiments may be referred to.

(Embodiment 1)
<General configuration of vehicle system 1>
Hereinafter, the present embodiment will be described with reference to the drawings. First, a vehicle system 1 will be described with reference to Fig. 1. As shown in Fig. 1, the vehicle system 1 includes a mobile terminal 2 and a vehicle unit 3.

The mobile terminal 2 is an information processing terminal such as a multi-function mobile phone. The mobile terminal 2 is carried by a user. In the following, an example will be described in which the mobile terminal 2 is a multi-function mobile phone. The vehicle-side unit 3 is used in a vehicle. Details of the vehicle-side unit 3 will be described later. In the following, the vehicle using the vehicle-side unit 3 will be described as, for example, an automobile.

<General configuration of mobile terminal 2>
Next, the portable terminal 2 will be described with reference to Fig. 2. As shown in Fig. 2, the portable terminal 2 includes a BLE module 21 and a UWB module 22. In this embodiment, for convenience, description of the configuration of the portable terminal 2 other than that related to wireless communication with the vehicle unit 3 is omitted.

The BLE module 21 is a communication module capable of short-range wireless communication conforming to Bluetooth Low Energy (Bluetooth is a registered trademark). Bluetooth Low Energy is abbreviated as BLE. The BLE module 21 may be configured, for example, with an IC, an antenna, a communication circuit, etc. The BLE module 21 establishes a communication connection with the vehicle-side unit 3 to perform short-range wireless communication.

The BLE module 21 periodically scans and receives advertising packets that are periodically transmitted from the vehicle-side unit 3. Upon receiving the advertising packets, the BLE module 21 transmits a connection request to the vehicle-side unit 3. If this connection request is accepted, a communication connection between the BLE module 21 and the vehicle-side unit 3 is established.

The UWB module 22 is a communication module capable of short-distance wireless communication using the UWB-IR (Ultra Wide Band - Impulse Radio) method. Hereinafter, short-distance wireless communication using the UWB-IR method will be referred to as UWB communication. UWB communication can also be referred to as ultra-wideband wireless communication. The UWB module 22 may be configured to include, for example, an IC, an antenna, a communication circuit, etc.

The UWB module 22 performs UWB communication by transmitting and receiving impulse-shaped radio waves (hereinafter, impulse signals). The impulse signals used in UWB communication are signals with an extremely short pulse width. For example, a signal with a pulse width of 2 ns may be used. The impulse signals used in UWB communication are signals with a bandwidth of 500 MHz or more (i.e., ultra-wide bandwidth). Frequency bands that can be used in UWB communication (hereinafter, UWB bands) include 3.1 GHz to 10.6 GHz, 3.4 GHz to 4.8 GHz, 7.25 GHz to 10.6 GHz, and 22 GHz to 29 GHz. When the UWB module 22 receives an impulse signal transmitted from the vehicle unit 3, it returns a response signal corresponding to this signal.

<General configuration of vehicle side unit 3>
Next, an example of a schematic configuration of the vehicle-side unit 3 will be described with reference to Fig. 3. As shown in Fig. 3, the vehicle-side unit 3 includes a communication ECU 30, a BLE module 31, and a UWB anchor 32. For example, the communication ECU 30 may be configured to be connected to an in-vehicle LAN 40. The BLE module 31 and the UWB anchor 32 may be configured to be connected to the communication ECU 30. The BLE module 31 and the UWB anchor 32 may be configured to be included in the communication ECU 30.

The BLE module 31 is a communication module that includes, for example, an IC, an antenna, a communication circuit, etc. The BLE module 31 performs short-range wireless communication conforming to BLE according to instructions from the communication ECU 30.

The UWB anchor 32 is a communication module consisting of, for example, an IC, an antenna, a communication circuit, etc. The UWB anchor 32 performs short-range wireless communication using the UWB-IR method according to instructions from the communication ECU 30. This UWB anchor 32 corresponds to an antenna. The UWB anchors 32 are provided at multiple locations inside and outside the vehicle. Three or more UWB anchors 32 may be provided in the vehicle, including an indoor anchor located inside the vehicle cabin and an outdoor anchor located outside the vehicle cabin. The UWB anchors 32 provided at multiple locations inside and outside the vehicle correspond to interior and exterior antennas. Each UWB anchor 32 may be set with a unique identifier (hereinafter, anchor ID).

Here, an example of the arrangement of UWB anchors 32 in this embodiment will be described with reference to FIG. 4. As an example, as shown in FIG. 4, four UWB anchors 32 may be arranged outside the cabin of the host vehicle, and two may be arranged inside the cabin of the host vehicle. The UWB anchors 32 arranged outside the cabin of the host vehicle (i.e., exterior anchors) are UWB anchors 32a, 32b, 32c, and 32d. The UWB anchors 32a, 32b, 32c, and 32d correspond to exterior antennas. The UWB anchors 32 arranged inside the cabin of the host vehicle (i.e., interior anchors) are UWB anchors 32e and 32f. The UWB anchors 32e and 32f correspond to interior antennas. The UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f correspond to interior and exterior antennas.

The UWB anchor 32a is disposed near the left corner of the front end of the vehicle. The UWB anchor 32b is disposed near the right corner of the front end of the vehicle. The UWB anchor 32c is disposed near the left corner of the rear end of the vehicle. The UWB anchor 32d is disposed near the right corner of the rear end of the vehicle. The UWB anchor 32e is disposed at the front of the vehicle interior. The UWB anchor 32d is disposed at the rear of the vehicle interior. The UWB anchors 32e and 32d, which are indoor anchors, are preferably provided in the ceiling part of the vehicle interior. This is because, even with indoor anchors, the influence of multipath caused by the vehicle body is suppressed and UWB communication with the mobile terminal 2 outside the vehicle interior is facilitated. The indoor anchor may be configured to be disposed on the front right side of the vehicle in the ceiling part. The indoor anchor may also be configured to be disposed in the center console. The outdoor anchor may be disposed on the left and right B pillars, the rear of the vehicle, etc.

The UWB anchor 32 also includes a timer that measures the time that elapses from when the UWB anchor 32 transmits an impulse signal until when the UWB anchor 32 receives an impulse signal as a response signal to the impulse signal (hereinafter, referred to as the round trip time). The UWB anchor 32 uses this timer to measure the round trip time. The UWB anchor 32 associates the measured round trip time with its own anchor ID and outputs the measured round trip time to the communication ECU 30. Note that the method of acquiring the round trip time described here is merely an example. Other methods may be used as long as the round trip time used for measuring the distance between the UWB anchor 32 and the mobile terminal 2 can be acquired. The order of communication between the UWB anchor 32 and the mobile terminal 2 is not limited to the order described above. In other words, the method of Two Way Ranging or the method of Double Sided Two Way Ranging may be used.

The communication ECU 30 includes, for example, a processor, a memory, an I/O, and a bus connecting these, and executes various processes by executing a control program stored in the memory. The communication ECU 30 executes various processes related to the control of communication in the BLE module 31 and the UWB anchor 32. The communication ECU 30 also executes processes related to determining the position of the mobile terminal 2 relative to the vehicle (hereinafter, terminal position determination related processes). The memory referred to here is a non-transiory tangible storage medium that non-temporarily stores computer-readable programs and data. The non-transiory tangible storage medium is realized by a semiconductor memory or a magnetic disk. This communication ECU 30 corresponds to an on-board device. Details of the communication ECU 30 will be described below.

<General Configuration of Communication ECU 30>
Here, an example of a schematic configuration of the communication ECU 30 will be described with reference to Fig. 3. As shown in Fig. 3, the communication ECU 30 includes a BLE instruction unit 301, a BLE acquisition unit 302, a UWB instruction unit 303, a UWB acquisition unit 304, a terminal distance estimation unit 305, a selection unit 306, and a terminal position determination unit 307 as functional blocks. Note that some or all of the functions executed by the communication ECU 30 may be configured in the form of hardware using one or more ICs or the like. Also, some or all of the functional blocks included in the communication ECU 30 may be realized by a combination of software execution by a processor and hardware members.

The BLE instruction unit 301 causes the BLE module 31 to transmit advertising packets. For example, the BLE instruction unit 301 may cause the BLE module 31 to periodically transmit advertising packets when the vehicle is parked and a certain time has elapsed since all the doors of the vehicle were locked. The end timing of the periodic transmission of advertising packets may be, for example, the timing when the vehicle starts to move.

The BLE acquisition unit 302 acquires information related to wireless communication with the mobile device 2, which is received by the BLE module 31. When a connection is established between the BLE module 21 of the mobile device 2 that received the advertising packet and the BLE module 31, the BLE acquisition unit 302 acquires information received by the BLE module 31 through short-range wireless communication with the BLE module 21.

The UWB instruction unit 303 causes the UWB anchor 32 to transmit an impulse signal. As an example, the impulse signal may be transmitted in sequence from a plurality of UWB anchors 32 provided in the vehicle. In the example of this embodiment, the impulse signal may be transmitted in sequence from the UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f at predetermined time intervals.

The UWB instruction unit 303 may start transmission of an impulse signal from the UWB anchor 32 when a connection between the BLE module 21 of the mobile terminal 2 and the BLE module 31 is established or when the connection is triggered by the establishment of the connection. This makes it possible to reduce the waste of transmitting an impulse signal from the UWB anchor 32 even when there is no mobile terminal 2 in the vicinity of the vehicle.

The UWB instruction unit 303 may determine whether a connection between the BLE module 21 and the BLE module 31 of the mobile terminal 2 is to be established or has been established, for example, from information acquired by the BLE acquisition unit 302. The establishment of a connection between the BLE module 21 and the BLE module 31 of the mobile terminal 2 may be determined, for example, from the reception by the BLE module 31 of a connection request transmitted from the BLE module 21 of the mobile terminal 2 that has received an advertising packet. The establishment of a connection between the BLE module 21 and the BLE module 31 of the mobile terminal 2 may be determined, for example, from the reception by the BLE module 31 of information transmitted by the BLE module 21 of the mobile terminal 2 via short-range wireless communication performed by establishing a connection.

The UWB acquisition unit 304 acquires information related to UWB communication received by the UWB anchor 32 when UWB communication is performed between the UWB module 22 of the mobile terminal 2 and the UWB anchor 32. The UWB acquisition unit 304 acquires the round trip time output from each of the multiple UWB anchors 32 provided in the vehicle. The UWB acquisition unit 304 may identify which UWB anchor 32 the round trip time is based on the anchor ID output from the UWB anchor 32. In this embodiment, the UWB acquisition unit 304 acquires the round trip time of each of the UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f from which a response signal was received by UWB communication.

The terminal distance estimation unit 305 estimates the distance of the mobile terminal 2 from the UWB anchor 32 (hereinafter, terminal distance) based on the impulse signal that can be transmitted and received between the mobile terminal 2 and the UWB anchor 32 by UWB communication. The terminal distance estimation unit 305 estimates the terminal distance for each of the UWB anchors 32 that can receive a response signal from among the multiple UWB anchors 32 installed in the vehicle. The terminal distance estimation unit 305 may estimate the terminal distance using the round trip time acquired by the UWB acquisition unit 304. In detail, the propagation time is calculated by subtracting the internal processing time of the mobile terminal 2 in UWB communication from the round trip time and dividing the result by 2. The terminal distance may be estimated as the value obtained by multiplying the calculated propagation time by the speed of light. Note that a standard value for the internal processing time may be stored in advance in the non-volatile memory of the communication ECU 30.

The selection unit 306 selects two UWB anchors 32 with the shortest terminal distance estimated by the terminal distance estimation unit 305 from among the multiple UWB anchors 32 installed in the vehicle. In the example of this embodiment, first, from among the four UWB anchors 32, UWB anchors 32a, 32b, 32c, and 32d that are exterior anchors, the selection unit 306 selects two UWB anchors 32 with the shortest terminal distance estimated by the terminal distance estimation unit 305. Next, from among the four UWB anchors 32, the two UWB anchors 32 selected from the exterior anchors and UWB anchors 32e and 32f that are interior anchors, the selection unit 306 selects two UWB anchors 32 with the shortest terminal distance estimated by the terminal distance estimation unit 305.

In addition, since an outdoor anchor is easier to directly receive a response signal from the mobile terminal 2 than an indoor anchor, the selection unit 306 may select at least an outdoor anchor as one of the two UWB anchors 32.

The terminal position determination unit 307 determines the position of the mobile terminal relative to the vehicle (hereinafter, terminal position) using the terminal distances for the two UWB anchors 32 selected by the selection unit 306, among the terminal distances estimated by the terminal distance estimation unit 305. As an example, the following may be performed.

First, in a horizontal coordinate system (hereinafter referred to as a planar coordinate system) with the reference point of the vehicle as the origin, a candidate point for the terminal position of the mobile terminal 2 that satisfies the terminal distance for the two UWB anchors 32 selected by the selection unit 306 is calculated. Two candidate points are calculated. Note that the position of the UWB anchor 32 in the planar coordinate system can be made available by storing information on the position of the UWB anchor 32 relative to the reference point of the vehicle in the non-volatile memory of the communication ECU 30 in advance. The reference point of the vehicle can be determined appropriately, and as an example, it can be the center of the rear wheel axle in the vehicle width direction.

Then, the two calculated candidate points are narrowed down to one candidate point. As an example, the candidates can be narrowed down to one point from the area in which the mobile terminal 2 exists (hereinafter, the candidate area), which is roughly estimated from the UWB anchor 32 selected by the selection unit 306. This is because the selection unit 306 selects a UWB anchor 32 with a shorter terminal distance, and therefore it is estimated that the mobile terminal 2 exists in an area closer to the selected UWB anchor 32 than to a UWB anchor 32 that was not selected.

The candidate area may be estimated from the UWB anchor 32 with the shortest terminal distance estimated by the terminal distance estimation unit 305 among the UWB anchors 32 selected by the selection unit 306. For example, if the UWB anchor 32 with the shortest terminal distance is UWB anchor 32a, the candidate area is estimated to be the area from the left side to the left front of the vehicle.

The candidate area may be inferred based on which two UWB anchors 32 out of the four exterior UWB anchors 32, UWB anchors 32a, 32b, 32c, and 32d, are selected by the selection unit 306. This makes it possible to infer in which of the four areas on the front, rear, left, and right sides of the vehicle the mobile terminal 2 is located, depending on the combination of two UWB anchors 32. Alternatively, the candidate area may be inferred based on which two UWB anchors 32 out of the six UWB anchors 32, UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f, of the areas further divided than the front, rear, left, and right sides of the vehicle the mobile terminal 2 is located.

The terminal position determination unit 307 may narrow down the two calculated candidate points to a candidate point that falls within the estimated area. The terminal position determination unit 307 then determines the one narrowed down candidate point as the terminal position. The terminal position determined by the terminal position determination unit 307 may be configured to be used for controlling the vehicle.

Here, an example of narrowing down the terminal position from two candidate points will be explained using FIG. 5. In the example of FIG. 5, an explanation will be given taking as an example a case where UWB anchors 32b and 32e are selected by the selection unit 306. CPA and CPB in FIG. 5 indicate two candidate points calculated by the terminal position determination unit 307. CA in FIG. 5 indicates a candidate area estimated by the terminal position determination unit 307. Of the two candidate points CPA and CPB, only candidate point CPA corresponds to candidate area CA, so the candidates are narrowed down to this candidate point CPA, which is determined as the terminal position.

As described above, the terminal position determination unit 307 determines the terminal position by narrowing down two candidate points of the terminal position determined from the terminal distances for the two UWB anchors 32 selected by the selection unit 306, among the terminal distances estimated by the terminal distance estimation unit 305, to one based on which UWB anchor 32 has the shorter terminal distance. The terminal position determination unit 307 may be configured to narrow down the two calculated candidate points to one candidate using another method.

<Terminal position determination related processing in communication ECU 30>
Next, an example of the flow of processing related to the determination of the terminal position of the portable terminal 2 in the communication ECU 30 (hereinafter, terminal position determination related processing) will be described with reference to the flowchart of Fig. 6. The flowchart of Fig. 6 may be configured to start when a communication connection between the BLE module 31 and the portable terminal 2 is established, for example.

First, in step S1, the UWB instruction unit 303 causes the UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f to transmit impulse signals in sequence at predetermined time intervals. When the mobile terminal 2 receives the impulse signal transmitted from the UWB anchor 32, a response signal is returned from the UWB module 22 of the mobile terminal 2. When the UWB anchor 32 receives this response signal, the UWB anchor 32 measures the round trip time and outputs it to the communication ECU 30.

In step S2, the UWB acquisition unit 304 acquires the round trip time for each of the UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f from which a response signal was received via UWB communication. In step S3, the terminal distance estimation unit 305 estimates the terminal distance for each UWB anchor 32 using the round trip time acquired in S2.

In step S4, the selection unit 306 uses the terminal distance estimated in S3 to select two of the four outdoor anchors, UWB anchors 32a, 32b, 32c, and 32d, that have the shortest terminal distance. In step S5, the selection unit 306 uses the terminal distance estimated in S3 to select two of the two outdoor anchors selected in S4 and the two indoor anchors, UWB anchors 32e and 32f, that have the shortest terminal distance.

In step S6, the terminal position determination unit 307 calculates two candidate points for the terminal position of the mobile terminal 2 using the terminal distances for the two UWB anchors 32 selected in S5. In step S7, the terminal position determination unit 307 estimates a candidate area from the UWB anchors 32 selected by the selection unit 306. In step S8, the terminal position determination unit 307 determines that the candidate point that falls within the candidate area estimated in S7, out of the two candidate points calculated in S6, is the terminal position.

In step S9, if it is time to end the terminal position determination related processing (YES in S9), the terminal position determination related processing is terminated. Examples of the timing to end the terminal position determination related processing may include when the vehicle doors are unlocked, or when the vehicle's drive source is started. On the other hand, if it is not time to end the terminal position determination related processing (NO in S9), the process returns to S1 and is repeated.

Summary of First Embodiment
When the mobile terminal 2 is located outside the vehicle cabin, the terminal distance estimated by the terminal distance estimation unit 305 based on the impulse signal transmitted and received by UWB communication may be erroneously estimated as a longer distance than the actual distance due to the effects of radio wave shielding by a human body, etc., and multipath. For example, when radio waves are shielded by a human body, the response signal cannot be directly received, but the response signal reflected by the vehicle body is received, resulting in the terminal distance being erroneously estimated as a longer distance than the actual distance.

In contrast, according to the configuration of embodiment 1, two UWB anchors 32 with the shorter estimated terminal distance are selected from the six UWB anchors 32a, 32b, 32c, 32d, 32e, and 32f, including indoor and outdoor anchors. The terminal position is then determined using the terminal distance for the selected UWB anchor 32. As described above, when the terminal distance is erroneously estimated, it is erroneously estimated to be a longer distance than the actual distance, so the shorter the estimated terminal distance, the less likely it is that the estimated terminal distance is erroneous.

Therefore, even if the terminal distance of the portable terminal 2 located outside the vehicle cabin is erroneously estimated, it is possible to exclude the terminal distance that is likely to have been erroneously estimated and determine the terminal position using a more accurate terminal distance. As a result, even when the terminal position is determined using UWB communication, it is possible to more accurately determine the position of the portable terminal 2 located outside the vehicle cabin.

Here, the effect of the configuration of the first embodiment will be described with reference to Figs. 7 and 8. Fig. 7 shows an example in which the mobile terminal 2 is carried in front of the user. In the example of Fig. 7, it is assumed that the direct transmission and reception of impulse signals between the UWB anchor 32b and the mobile terminal 2 is blocked by the user's body. In the example of Fig. 7, it is assumed that the two UWB anchors 32 with the shorter estimated terminal distance are the UWB anchors 32d and 32e. Fig. 8 shows an example in which the mobile terminal 2 is carried behind the user. In the example of Fig. 8, it is assumed that the direct transmission and reception of impulse signals between the UWB anchor 32d and the mobile terminal 2 is blocked by the user's body. In the example of Fig. 8, it is assumed that the two UWB anchors 32 with the shorter estimated terminal distance are the UWB anchors 32b and 32e.

As shown in the example of FIG. 7, when the direct transmission and reception of impulse signals between UWB anchor 32b and mobile terminal 2 is blocked by the user's body, the terminal distance for UWB anchor 32b is erroneously estimated to be longer than the actual distance. Even in such a case, the UWB anchor 32 used to determine the terminal position is UWB anchor 32d, 32e, which has a shorter estimated terminal distance. Therefore, it is not necessary to use the erroneously estimated terminal distance for UWB anchor 32b in determining the terminal position. As a result, it is possible to determine the terminal position with higher accuracy.

On the other hand, as shown in the example of FIG. 8, if the direct transmission and reception of impulse signals between UWB anchor 32d and mobile terminal 2 is blocked by the user's body, the terminal distance for UWB anchor 32d is erroneously estimated to be longer than the actual distance. Even in such a case, the UWB anchor 32 used to determine the terminal position is UWB anchor 32b or 32e, which has a shorter estimated terminal distance. Therefore, it is not necessary to use the erroneously estimated terminal distance for UWB anchor 32d in determining the terminal position. As a result, it is possible to determine the terminal position with higher accuracy.

In addition, according to the configuration of embodiment 1, the terminal position is determined using the terminal distances for the two UWB anchors 32 with the shorter estimated terminal distances, making it less likely that an erroneously estimated terminal distance will be used to determine the terminal position. This makes it possible to determine the terminal position with particularly high accuracy.

(Embodiment 2)
In the first embodiment, the terminal location is determined using the terminal distances between the two estimated UWB anchors 32, but the present invention is not limited to this. For example, the terminal location may be determined using the terminal distances between the three estimated UWB anchors 32 (hereinafter, referred to as the second embodiment).

An example of the second embodiment will be described below with reference to the drawings. The vehicle system 1 of the second embodiment is similar to the vehicle system 1 of the first embodiment, except that the vehicle system 1 of the second embodiment includes a communication ECU 30a instead of the communication ECU 30.

Here, an example of the schematic configuration of the communication ECU 30a will be described with reference to FIG. 9. As shown in FIG. 9, the communication ECU 30a includes, as functional blocks, a BLE instruction unit 301, a BLE acquisition unit 302, a UWB instruction unit 303, a UWB acquisition unit 304, a terminal distance estimation unit 305, a selection unit 306a, and a terminal position determination unit 307a. The communication ECU 30a is similar to the communication ECU 30 of embodiment 1, except that the communication ECU 30a includes a selection unit 306a and a terminal position determination unit 307a instead of the selection unit 306 and the terminal position determination unit 307.

The selection unit 306a selects three UWB anchors 32 with the shortest terminal distances estimated by the terminal distance estimation unit 305 from among the multiple UWB anchors 32 installed in the vehicle. In the example of this embodiment, first, from among the four UWB anchors 32, UWB anchors 32a, 32b, 32c, and 32d that are exterior anchors, two UWB anchors 32 with the shortest terminal distances estimated by the terminal distance estimation unit 305 are selected. Next, from among the four UWB anchors 32, the two UWB anchors 32 selected from the exterior anchors and UWB anchors 32e and 32f that are interior anchors, three UWB anchors 32 with the shortest terminal distances estimated by the terminal distance estimation unit 305 are selected.

In addition, since an outdoor anchor is easier to directly receive a response signal from the mobile terminal 2 than an indoor anchor, the selection unit 306a may select three UWB anchors 32 to include at least an outdoor anchor.

The terminal position determination unit 307 determines the terminal position using the terminal distances for the three UWB anchors 32 selected by the selection unit 306a, among the terminal distances estimated by the terminal distance estimation unit 305. As an example, the terminal position may be determined using the principle of triangulation based on the terminal distances for the three UWB anchors 32 selected by the selection unit 306a and the positions of these UWB anchors 32 relative to the reference point of the vehicle.

Even with the configuration of the second embodiment, the UWB anchor 32 with the shorter estimated terminal distance is selected, and the terminal position is determined using the terminal distance for the selected UWB anchor 32. Therefore, even if the terminal distance of the mobile terminal 2 located outside the vehicle cabin is erroneously estimated, it is possible to exclude the terminal distance that is likely to have been erroneously estimated and determine the terminal position using the more accurate terminal distance. As a result, even when the terminal position is determined using UWB communication, it is possible to more accurately determine the position of the mobile terminal 2 outside the vehicle cabin. Furthermore, with the configuration of the second embodiment, the terminal position is determined using the terminal distances for three UWB anchors 32, making it easier to narrow down the terminal position to one point.

(Embodiment 3)
In the above embodiment, the same communication ECU 30, 30a performs the functions of the BLE instruction unit 301, the BLE acquisition unit 302, and the UWB instruction unit 303, and the functions of the UWB acquisition unit 304, the terminal distance estimation unit 305, the selection unit 306, and the terminal position determination unit 307. However, this is not necessarily limited to this. For example, an ECU performing the functions of the BLE instruction unit 301, the BLE acquisition unit 302, and the UWB instruction unit 303 may be separate from an ECU performing the functions of the UWB acquisition unit 304, the terminal distance estimation unit 305, the selection unit 306, and the terminal position determination unit 307. In this case, the ECU performing the functions of the UWB acquisition unit 304, the terminal distance estimation unit 305, the selection unit 306, and the terminal position determination unit 307 corresponds to an in-vehicle device.

Note that the present disclosure is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. The technical scope of the present disclosure also includes embodiments obtained by appropriately combining the technical means disclosed in different embodiments. The control unit and the method described in the present disclosure may be realized by a dedicated computer that constitutes a processor programmed to execute one or more functions embodied in a computer program. Alternatively, the device and the method described in the present disclosure may be realized by a dedicated hardware logic circuit. Alternatively, the device and the method described in the present disclosure may be realized by one or more dedicated computers that are configured by combining a processor that executes a computer program with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer.

1 Vehicle system, 2 Portable terminal, 3 Vehicle unit, 30, 30a Communication ECU (vehicle-mounted device), 32 UWB anchor (antenna), 32a, 32b, 32c, 32d UWB anchor (interior/exterior antenna, exterior antenna), 32e, 32f UWB anchor (interior/exterior antenna, indoor antenna), 304 Terminal position identification unit, 305 Terminal distance estimation unit, 306, 306a Selection unit, 307, 307a Terminal position determination unit

Claims (3)

Used in vehicles,
An in-vehicle device including a terminal distance estimation unit (305) that estimates a terminal distance, which is a distance of the portable terminal from an antenna (32) provided in the vehicle, based on an impulse signal that can be transmitted and received by ultra-wideband wireless communication between the portable terminal carried by a user and the antenna,
the terminal distance estimation unit estimates the terminal distance for each of three or more indoor and outdoor antennas (32a, 32b, 32c, 32d, 32e, 32f) including an indoor antenna (32e, 32f) provided in a cabin of the vehicle and an outdoor antenna (32a, 32b, 32c, 32d) provided outside the cabin of the vehicle;
a selection unit (306, 306a) for selecting, from among the internal and external antennas, at least two antennas having a shorter terminal distance estimated by the terminal distance estimation unit and less than the total number of the internal and external antennas;
a terminal position determination unit (307, 307a) that determines a position of the mobile terminal with respect to the vehicle by using the terminal distance for the antenna selected by the selection unit, among the terminal distances estimated by the terminal distance estimation unit ,
The selection unit (306) selects two of the antennas from among the internal and external antennas, the two antennas having the shorter terminal distance estimated by the terminal distance estimation unit;
The terminal position determination unit (307) is an in-vehicle device that determines the position of the mobile terminal relative to the vehicle by narrowing down two candidate points for the position of the mobile terminal relative to the vehicle, which are determined from the terminal distances for the two antennas selected by the selection unit, among the terminal distances estimated by the terminal distance estimation unit, to one based on which antenna the terminal distance is shorter . In claim 1 ,
The indoor antenna is provided on a ceiling portion inside the passenger compartment of the vehicle. Used in vehicles,
A portable terminal (2) carried by a user;
three or more antennas including an indoor antenna (32e, 32f) provided inside a vehicle cabin and an outdoor antenna (32a, 32b, 32c, 32d, 32e, 32f) provided outside the vehicle cabin;
A vehicle system comprising an on-vehicle device (30, 30a) according to claim 1 or 2 .

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