JP7634371B2 - Communication Equipment - Google Patents

Description

The present invention relates to a communication device.

In recent years, technology has been developed that allows one device to estimate the position of another device based on the results of transmitting and receiving signals between the devices. For example, Patent Document 1 discloses a technology in which an ultra-wide band (UWB) receiver uses a UWB signal to estimate the angle of arrival of a wireless signal transmitted from a UWB transmitter.

International Publication No. 2015/176776

In a system like the one described above, the relative positions of the multiple antennas may affect the accuracy of estimating the angle of arrival of a wireless signal.

Therefore, the present invention has been made in consideration of the above problems, and the object of the present invention is to provide a new and improved communication device that can estimate the arrival angle of a signal with higher accuracy.

In order to solve the above problem, according to one aspect of the present invention, a communication device is provided that includes at least a first antenna and a second antenna for transmitting and receiving signals that comply with a prescribed communication standard, and the first antenna and the second antenna are arranged so that, based on the relationship between the signal arrival angle and the phase difference between the antennas, the absolute value of the phase difference between the antennas is reduced when the signal is received from the first region, where the estimation accuracy of the signal arrival angle is desired to be improved, is compared with the signal received from a second region other than the first region.

As described above, the present invention makes it possible to estimate the signal arrival angle with greater accuracy.

FIG. 1 is a block diagram showing an example of the configuration of a system 1 according to the present embodiment. 1 is an explanatory diagram for explaining an outline of estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20 based on a signal w1 transmitted and received between the vehicle-mounted device 10 and the portable device 20. FIG. 1 is an explanatory diagram for explaining an outline of estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20 based on a signal w1 transmitted and received between the vehicle-mounted device 10 and the portable device 20. FIG. FIG. 2 is a sequence diagram for explaining an example of processing related to distance estimation and angle estimation executed in the system 1 according to the present embodiment. 1 is a graph showing the relationship between the phase difference between antennas and the radio wave arrival angle. FIG. 2 is an explanatory diagram for explaining the arrangement of antennas according to the embodiment. FIG. 2 is an explanatory diagram for explaining an example of a flow of operation processing of the system 1 according to the present embodiment.

The preferred embodiment of the present invention will be described in detail below with reference to the attached drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

1. Embodiment
<<1.1. System configuration example>>
First, a schematic configuration of a system 1 according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the system 1 according to the present embodiment.

As shown in FIG. 1, the system 1 according to this embodiment includes an in-vehicle device 10 and a portable device 20.

(In-vehicle device 10)
The vehicle-mounted device 10 according to the present embodiment is an example of a communication device. The vehicle-mounted device 10 according to the present embodiment may be, for example, a communication unit mounted on a moving body in which a user is permitted to ride (for example, a vehicle owned by the user or a vehicle temporarily loaned to the user).

As shown in FIG. 1, the vehicle-mounted device 10 according to this embodiment has a control unit 110, a communication unit 120, and a processing unit 130.

The control unit 110 controls the overall operation of the vehicle-mounted device 10. For example, the control unit 110 controls the transmission and reception of wireless signals that comply with a prescribed communication standard. More specifically, the control unit 110 controls the transmission and reception of ultra-wideband signals (hereinafter referred to as UWB signals).

Although a UWB signal is given as an example of a wireless signal that complies with a prescribed communication standard, wireless signals that comply with a prescribed communication standard are not limited to UWB signals. For example, the prescribed communication standard according to this embodiment includes various communication standards that are capable of measuring the propagation time of a signal between wireless communication devices.

Furthermore, the functions of the control unit 110 according to this embodiment are realized, for example, by various processors.

The communication unit 120 functions as a first antenna, a second antenna, and a third antenna that transmit and receive wireless signals that comply with a prescribed communication standard. For example, the communication unit 120 receives a Poll (Polling) signal transmitted from the portable device 20. After receiving the Poll signal, the communication unit 120 transmits a Resp (Response) signal to the portable device 20 according to the control of the control unit 110. The communication unit 120 also receives a Final signal transmitted from the portable device 20 in response to the Resp signal.

The processing unit 130 executes a process of estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20, for example, based on a signal transmitted and received between the vehicle-mounted device 10 and the portable device 20. For example, the processing unit 130 may execute a process of estimating the angle of arrival of a signal based on a received signal. The processing unit 130 may also execute a process of estimating the distance between the vehicle-mounted device 10 and the portable device 20 based on a transmitted and received signal. The processing unit 130 may also estimate the three-dimensional position of the portable device 20 based on the estimated angle of arrival of the signal and the distance between the vehicle-mounted device 10 and the portable device 20.

The process of estimating the positional relationship between the devices will be described in detail later, but the processing unit 230 of the portable device 20 may execute the process of estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20. In this case, the communication unit 120 may transmit, for example, information required to estimate the positional relationship between the devices to the portable device 20.

(Portable device 20)
The portable device 20 according to the present embodiment may be, for example, an electronic key, a smartphone, a wearable terminal, etc. The portable device 20 according to the present embodiment is, for example, carried by a user, and transmits and receives wireless communications conforming to prescribed communications between the portable device 20 and an in-vehicle device 10 mounted on a moving body such as a vehicle used by the user.

As shown in FIG. 1, the portable device 20 according to this embodiment has a control unit 210, a communication unit 220, and a processing unit 230.

The control unit 210 controls the overall operation of the portable device 20. For example, the control unit 210 controls the transmission and reception of wireless signals that comply with a prescribed communication standard.

The communication unit 220 transmits and receives wireless signals that comply with a prescribed communication standard, for example. For example, the communication unit 220 transmits a Poll signal to the vehicle-mounted device 10. The communication unit 220 also receives a Resp signal from the communication unit 120 provided in the vehicle-mounted device 10. The communication unit 220 also transmits a Final signal in response to the Resp signal, according to the control of the control unit 210.

The processing unit 230 performs processing to estimate the positional relationship between the vehicle-mounted device 10 and the portable device 20, for example, based on signals transmitted and received between the vehicle-mounted device 10 and the portable device 20.

Next, an example of a process for estimating positional relationships will be described with reference to FIG. 2.

1.2. Estimation of Positional Relationship
2 and 3 are explanatory diagrams for explaining an example of a process for estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20 based on a signal w1 transmitted and received between the vehicle-mounted device 10 and the portable device 20. FIG.

As shown in FIG. 2, the vehicle-mounted device 10 is disposed, for example, on the ceiling surface of the vehicle V1, and has multiple antennas. Note that the scale of the vehicle-mounted device 10 and each antenna equipped on the vehicle-mounted device 10 is illustrated large for the purpose of explanation, and may differ from the actual scale. Here, the configuration of the antennas equipped on the vehicle-mounted device 10 will be described with reference to FIG. 3.

As shown in FIG. 3, the vehicle-mounted device 10 has, for example, antenna A1, antenna A2, antenna A3, and antenna A4. Antenna A3 is arranged so that the line connecting antenna A1 and antenna A3 is perpendicular to the line connecting antenna A1 and antenna A2. Antenna A4 is arranged so that the line connecting antenna A2 and antenna A4 is perpendicular to the line connecting antenna A1 and antenna A2.

In addition, in the local coordinate system of the vehicle-mounted device 10 according to this embodiment, for example, when antenna A1 is the origin, the direction of the straight line connecting antennas A1 and A2 is the X-axis, the direction in which the straight line connecting antennas A1 and A3 is perpendicular to the X-axis is the Y-axis, and the vertical direction of antenna A1 is the Z-axis.

For example, antenna A1 may be a first antenna, antenna A2 may be a second antenna, and antenna A3 may be a third antenna.

Unless otherwise specified, in this specification, the line connecting antennas A1 and A2 will be described as the X-axis, and the line connecting antennas A1 and A3 as the Y-axis, but the definition of the coordinate axes is not limited to this example. For example, the local coordinate system of the vehicle-mounted device 10 may have antenna A4 as the origin, the line connecting antennas A3 and A4 as the X-axis, the line connecting antennas A2 and A4 as the Y-axis, and the vertical direction of antenna A4 as the Z-axis.

As shown in FIG. 3, the spacing between adjacent antennas may be, for example, 1/2 wavelength, but may also be other spacings. The arrangement of the four antennas is not limited to a square, and may be a parallelogram, a trapezoid, a rectangle, or any other shape.

The number of antennas is not limited to four. For example, the number of antennas is at least two, so the main claim specifies at least a first antenna and a second antenna, since the signal arrival angle can be estimated. The above describes the antenna configuration of the vehicle-mounted device 10.

Returning now to FIG. 2, an example of position information included in the positional relationship between the vehicle-mounted device 10 and the portable device 20 will be described. As shown in FIG. 2, the position information includes distance information between the vehicle-mounted device 10 and the portable device 20. For example, the distance information includes a distance R from the origin of the local coordinate system of the vehicle-mounted device 10 to the portable device 20. The distance R corresponds to the distance between the vehicle-mounted device 10 and the portable device 20. More specifically, the distance R is the distance between an antenna (e.g., antenna A1) located at the origin of the local coordinate system of the vehicle-mounted device 10 and an antenna of the same type provided on the portable device 20. Note that the distance R is estimated based on a signal transmitted and received between the antenna at the origin of the local coordinate system and the portable device 20.

The position information also includes angle information at which the portable device 20 is located. The angle information includes, for example, the angle θ between the X-axis and the signal w1 transmitted by the portable device 20, and the angle Φ between the Y-axis and the signal w1 transmitted by the portable device 20. The angles θ and Φ are the angles of arrival of the signal w1, respectively.

Below, an example of the flow of estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20 according to this embodiment is described.

(1) Distance Estimation The processing unit 130 of the vehicle-mounted device 10 or the processing unit 230 of the portable device 20 performs distance measurement processing. The distance measurement processing is processing for estimating the distance between the vehicle-mounted device 10 and the portable device 20. In other words, the distance measurement processing is processing for estimating the distance R shown in Fig. 2. The distance measurement processing includes transmitting and receiving a distance measurement signal and estimating the distance R based on the time required for transmitting and receiving the distance measurement signal.

In the distance measurement process, multiple distance measurement signals can be transmitted and received between the vehicle-mounted device 10 and the portable device 20. Of the multiple distance measurement signals, the distance measurement signal transmitted from one device to the other device is referred to as a Poll signal. The distance measurement signal transmitted in response to the Poll signal from the device that received the Poll signal to the device that transmitted the Poll signal is referred to as a Resp signal. The distance measurement signal transmitted in response to the Resp signal from the device that received the Resp signal to the device that transmitted the Resp signal is referred to as a Final signal.

(2) Arrival Angle Estimation The processing unit 130 of the vehicle-mounted device 10 or the processing unit 230 of the portable device 20 estimates the angle θ and the angle Φ shown in Fig. 2 as the arrival angle of the signal w1. At least one of the above-mentioned distance measurement signals may be used as the signal for arrival angle estimation. In this specification, the Final signal will be described as the signal for arrival angle estimation.

Below, an example of processing related to distance estimation and arrival angle estimation is described with reference to Figure 4.

Figure 4 is a sequence diagram for explaining an example of processing related to distance estimation and arrival angle estimation executed in the system 1 according to this embodiment. In Figure 4, the antenna possessed by the portable device 20 is referred to as Tag.

First, the Tag of the portable device 20 transmits a Poll signal to the antenna A1 of the vehicle-mounted device 10 (S102).

Next, the antenna A1 of the vehicle-mounted device 10 transmits a Resp signal to the Tag of the portable device 20 in response to the Poll signal (S104).

Then, the Tag of the portable device 20 transmits a Final signal to the antennas A1, A2, A3, and A4 of the vehicle-mounted device 10 in response to the Resp signal (S106).

Here, the time length from when the portable device 20 transmits the Poll signal to when it receives the Resp signal is defined as time length T1, and the time length from when it receives the Resp signal to when it transmits the Final signal is defined as time length T2. The time length from when the vehicle-mounted device 10 receives the Poll signal to when it transmits the Resp signal is defined as time length T3, and the time length from when it transmits the Resp signal to when it receives the Final signal is defined as time length T4.

The distance R may be calculated using each of the time lengths described above. For example, the processing unit 130 of the vehicle-mounted device 10 calculates the propagation time τ of the signal using the time length T1, the time length T2, the time length T3, and the time length T4. For example, the processing unit 130 may calculate the propagation time τ of the signal using the following formula:
τ=(T1×T4−T2×T3)/(T1+T2+T3+T4)
(Formula 1)

The processing unit 130 may then multiply the calculated signal propagation time τ by the known signal speed to estimate the distance R between the vehicle-mounted device 10 and the portable device 20.

In the above description, the processing unit 130 estimates the distance R between the vehicle-mounted device 10 and the portable device 20 based on the signal transmitted and received between the antenna A1 and the Tag of the portable device. However, the vehicle-mounted device 10 may transmit and receive signals using another antenna, or may transmit and receive signals using multiple antennas.

The Poll signal, Resp signal, and Final signal may be transmitted and received by any device. For example, any antenna of the vehicle-mounted device 10 may transmit the Poll signal. In this case, the antenna of the portable device 20 may transmit the Resp signal.

Furthermore, the method of calculating the signal propagation time τ is not limited to the method using Equation 1. For example, the signal propagation time can also be calculated by subtracting the time length T3 from the time length T1 and dividing the resulting time length by 2.

Next, the arrival angle of the signal may be calculated from the phase difference of the Final signal received by adjacent antennas among the antennas. For example, the phase of the Final signal received by antenna A1 is phase P _A1 , the phase of the Final signal received by antenna A2 is phase P _A2 , the phase of the Final signal received by antenna A3 is phase P _A3 , and the phase of the Final signal received by antenna A4 is phase P _A4 . In this case, the phase differences Pd _A12 and Pd _A34 between adjacent antennas in the X-axis direction and the phase differences Pd _A13 and Pd _A24 between adjacent antennas in the Y-axis direction are respectively expressed by the following equations.

Pd _A12 = (P _A2 - _{P A1} )
Pd _A34 = (P _A4 - P _A3 )
Pd _A13 = (P _A3 - P _A1 )
Pd _A24 = (P _A4 - P _A2 )
(Formula 2)

Here, the formed angles θ and Φ are expressed by the following equations: where λ is the wavelength of the radio wave, and d is the distance between the antennas.
θorΦ=arccos(λ×Pd/(2πd))
(Formula 3)

Therefore, the processing unit 130 calculates the arrival angle of the signal based on Equation 2 and Equation 3 using the following equations.
θ _A12 = arccos(λ×(P _A2 −P _A1 )/(2πd))
θ _A34 = arccos(λ×(P _A4 −P _A3 )/(2πd))
Φ _A13 = arccos(λ×(P _A3 - _{P A1} )/(2πd))
Φ _A24 = arccos(λ×(P _A4 - _{P A2} )/(2πd))
(Formula 4)

The processing unit 130 may calculate the angle θ as the average value of θ _A12 and θ _A34 , or may estimate it as the angle θ as either one of θ _A12 or θ _A34 . Similarly, the processing unit 130 may calculate the angle Φ as the average value of Φ _A13 and Φ _A24 , or may estimate it as the angle Φ as either one of Φ _A13 or Φ _A24 .

The processing unit 130 may also estimate the three-dimensional position of the portable device 20 based on the coordinate system of the vehicle-mounted device 10 of the portable device 20 using the estimated distance R and the angle θ or the angle Φ.

For example, the processing unit 130 may estimate the three-dimensional position of the portable device 20 using Equation 5.
x = R × cos θ
y = R × cos Φ
z=√(R ² −x ² −y ² )
(Formula 5)

The above describes the process for estimating the positional relationship between the vehicle-mounted device 10 and the portable device 20 in this embodiment.

<<1.3. Estimation error of angle of arrival>>
As described above, in order for the processing unit 130 to estimate the three-dimensional position of the portable device 20, it is necessary to estimate the angle θ and the angle Φ, that is, the radio wave arrival angle of the signal, with high accuracy.

However, the further the angles θ and Φ deviate from 90 degrees, the greater the estimation error may be. More specifically, phase noise may be superimposed on the phase of the received signal, and an estimation error in the signal arrival angle may occur due to a phase shift of the signal caused by the phase noise. The further the signal arrival angle deviates from 90 degrees, the greater the estimation error in the signal arrival angle due to the phase shift.

Figure 5 is a graph showing the relationship between the phase difference between antennas and the radio wave arrival angle. In Figure 5, the vertical axis is the phase difference between adjacent antennas, and the horizontal axis is the radio wave arrival angle of the signal.

In Figure 5, for example, it is assumed that phase noise is superimposed on the signals received by two antennas, causing a phase difference of the signals received by the two antennas to have a deviation of Δpd. When this deviation Δpd occurs, as shown in Figure 5, the closer the angle is to 90 degrees, the smaller the estimation error of the radio wave arrival angle, and the farther it is from 90 degrees, the larger the estimation error of the radio wave arrival angle can be.

For example, when a signal arrives from a certain direction on the Y axis (i.e., the radio wave arrival angle is 90 degrees), the processing unit 130 can estimate the angle θ with high accuracy.

On the other hand, since the two adjacent antennas used to calculate the angle Φ are each located on the Y axis, when a signal arrives from a direction on the Y axis (i.e., the radio wave arrival angle is 0 degrees or 180 degrees), the processing unit 130 can estimate the angle Φ, which is larger than the angle θ and includes an estimation error caused by a phase shift.

In other words, there is a trade-off between the angle θ and the angle Φ, and improving the estimation accuracy of one may result in a decrease in the estimation accuracy of the other.

Therefore, the vehicle-mounted device 10 according to this embodiment is a device in which the antenna arrangement has been ingeniously designed to reduce the effects of estimation errors caused by phase shifts between the angles θ and Φ in areas where it is desired to further improve the estimation accuracy.

Specifically, a first region where it is desired to improve the estimation accuracy of the signal arrival angle and a second region other than the first region are defined, and adjacent antennas are arranged so that the absolute value of the phase difference between the antennas when they receive a signal from the first region is smaller than the absolute value of the phase difference between the antennas when they receive a signal from the second region.

For example, based on the relationship between the radio wave arrival angle and the phase difference between the antennas described above, antennas A1 and A2 are positioned such that the absolute value of the phase between the antennas when a signal is received from the first region is smaller than when a signal is received from the second region. This allows the processing unit 150 to reduce the effects of phase shifts and calculate the angle θ with high accuracy.

Also, antenna A3 is arranged so that the line connecting antenna A1 and antenna A3 is perpendicular to the line connecting antenna A1 and antenna A2. In this case, antenna A1, antenna A2, and antenna A3 are arranged so that the absolute value of the inter-antenna phase difference between antenna A1 and antenna A2 and between antenna A1 and antenna A3 when a signal is received from the first area is reduced by comparing the signal received from the first area with the signal received from the second area based on the relationship between the radio wave arrival angle and the phase difference between antennas A1 and A2 and the phase difference between antenna A1 and antenna A3 when a signal is received from the first area. This allows the processing unit 150 to reduce the influence of the phase shift and calculate the angles θ and Φ with high accuracy. Below, an example of the arrangement of multiple antennas will be described in more detail with reference to FIG. 6.

<<1.4. Antenna placement>>
6 is an explanatory diagram for explaining the arrangement of antennas according to this embodiment. First, a first region for which it is desired to estimate the arrival angle of a signal is set to two boarding and alighting positions of a vehicle V1. Here, the two boarding and alighting positions may be a driver's door D1 and a passenger's door P1 as shown in FIG. 6.

The vehicle-mounted device 10 may also be mounted in the center of a straight line connecting two boarding and disembarking positions. For example, if the length connecting the driver's door D1 and the passenger door P1 is L, the center of the vehicle-mounted device 10 may be located at the center position of L (1/2L). This allows the processing unit 130 to estimate the signal arrival angle with higher accuracy in either of the two regions where it is desired to estimate the signal arrival angle.

As shown in FIG. 6, when signal w1 is received from the first region, each antenna is positioned so that the angles θ and Φ, which are the angles of arrival of signal w1, are not close to 0 degrees or 180 degrees. More specifically, each antenna may be positioned so that the angles θ and Φ are close to approximately 45 degrees and approximately 135 degrees, respectively. This allows the processing unit 130 to estimate the angle of arrival of signal w1 with high accuracy when a signal is received from the first region.

In FIG. 6, the first region is in the left-right direction of the vehicle V1, but the present invention is not limited to this example. The first region may be in any direction, for example, in the directions of the four corners of the vehicle, or in the front-rear direction of the vehicle. In addition, if the first region for which the arrival angle of a signal is to be estimated changes, the control unit 110 of the vehicle-mounted device 10 may control the vehicle-mounted device 10 to rotate according to the changed region.

In addition, multiple vehicle-mounted devices 10 may be provided at different positions on the vehicle V1. Each of the vehicle-mounted devices 10 mounted at different positions on the vehicle V1 can estimate the arrival angle of a signal, thereby improving the estimation accuracy in all directions.

The above describes the arrangement of the antennas of the vehicle-mounted device 10 according to this embodiment. Next, an example of the operation process of the system 1 according to this embodiment will be described with reference to FIG. 7.

2. Operation processing example
7 is an explanatory diagram for explaining an example of the flow of operation processing of the system 1 according to this embodiment. First, the communication unit 120 receives a Poll signal from the portable device 20 (S202).

Next, the communication unit 120 transmits a Resp signal to the portable device 20 in response to the Poll signal (S204).

Next, the communication unit 120 receives a Final signal from the portable device 20 in response to the transmitted Resp signal (S206).

Then, the processing unit 130 calculates the distance between the vehicle-mounted device 10 and the portable device 20, i.e., the distance measurement value, based on each signal transmitted and received in S202 to S206 (S208).

Then, the processing unit 130 calculates the angle of arrival of the Final signal based on the phase difference between each adjacent antenna among the Final signals received by antennas A1 to A4 in S206 (S210).

Next, the processing unit 130 estimates the three-dimensional position of the portable device 20 based on the calculated distance measurement value and the arrival angle of the signal (S212).

Then, the processing unit 130 judges whether or not the three-dimensional position of the portable device 20 estimated in S212 satisfies a predetermined criterion. If it is judged that the predetermined criterion is satisfied (S214/Yes), the processing proceeds to S216, and if it is judged that the predetermined criterion is not satisfied (S214/No), the vehicle-mounted device 10 ends the processing.

If it is determined that the predetermined criteria are met (S214/Yes), the control unit 110 performs control related to unlocking or locking the doors of the vehicle V1 (S216), and the in-vehicle device 10 ends the processing. Note that the control related to S216 may be executed by another control device.

The antenna arrangement and control according to this embodiment allows, for example, the position of a user holding a portable device 20 near the boarding and disembarking position to be estimated with high accuracy, and control such as unlocking or locking the doors of the vehicle V1 can be more effectively achieved.

<3. Supplementary Information>
Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

For example, the series of processes performed by each device described in this specification may be realized using software, hardware, or a combination of software and hardware. The programs constituting the software are stored in advance, for example, in a recording medium (non-transitory media) provided inside or outside each device. Then, each program is loaded into RAM when executed by a computer, for example, and executed by a processor such as a CPU. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, or a flash memory. The computer programs may also be distributed, for example, via a network, without using a recording medium.

In addition, the processes described in this specification using sequence diagrams do not necessarily have to be performed in the order shown in the diagrams. For example, some processing steps may be performed in parallel. Furthermore, additional processing steps may be employed, and some processing steps may be omitted.

10: Vehicle-mounted device, 110: Control unit, 120: Communication unit, 130: Processing unit, 20: Portable device, 210: Control unit, 220: Communication unit, 230: Processing unit

Claims (11)

at least a first antenna , a second antenna, and a third antenna for transmitting and receiving signals conforming to a prescribed communication standard;
Equipped with
the third antenna is disposed such that a straight line connecting the first antenna and the third antenna or a straight line connecting the second antenna and the third antenna is orthogonal to a straight line connecting the first antenna and the second antenna,
the first antenna , the second antenna , and the third antenna are arranged such that, based on a relationship between a signal arrival angle and a phase difference between antennas, an absolute value of the phase difference between adjacent antennas when the signal is received from a first region in which it is desired to improve the estimation accuracy of the signal arrival angle is smaller than an absolute value of the phase difference between adjacent antennas when the signal is received from a second region that is a region other than the first region.
Communications equipment. The present invention is used in an apparatus that is controlled based on the estimation result of the signal arrival angle,
The communication device according to claim 1 . Mounted on a moving vehicle,
A communication device according to claim 1 or 2 . Two boarding and alighting positions among the boarding and alighting positions of the moving body for which the estimation accuracy is desired to be improved are set as the first region, and the vehicle is mounted at a center position of a straight line connecting the two boarding and alighting positions.
The communication device according to claim 3 . The boarding and alighting position includes a position of a driver's door and a passenger's door of the moving body as the first area,
The communication device according to claim 4 . Mounted on the ceiling surface of the moving body,
A communication device according to any one of claims 3 to 5. The transmitted and received signals are used in a calculation to estimate an angle of arrival of the signal received from another communication device.
A communication device according to any one of claims 3 to 6 . The transmitted and received signals are used in a calculation to estimate a distance between the communication device and the other communication device.
The communication device according to claim 7 . The estimated arrival angle of the signal and the distance between the communication device and the other communication device are used in a process of estimating a three-dimensional position of the other communication device.
The communication device according to claim 8 . The process of estimating the three-dimensional position is used to unlock or lock a door of the moving object.
10. The communication device of claim 9 . The signal includes a radio signal conforming to ultra-wideband wireless communication.
A communication device according to any one of claims 1 to 10 .

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