JP7364474B2 - Directional control devices and directional control systems - Google Patents

Description

The present invention relates to a directional control device and a directional control system.

When transmitting and receiving wireless data while moving, such as in a moving vehicle, the transmission and reception conditions constantly change, so an antenna system is equipped with multiple antennas and appropriately selects and switches to the antenna with the best reception condition at that time. and its control device have been proposed in the past.

For example, in Patent Document 1, a transmitting station position vector r from the own vehicle position is calculated based on the transmission position P _T and the own vehicle position P _n obtained from the navigation system, and the own vehicle position P Based on _n , the own vehicle travel vector v is calculated. Next, a transmitting station angle θ ₂ from the vehicle position is calculated based on the transmitting station position vector r, and a vehicle traveling angle θ ₁ is calculated based on the vehicle traveling vector v. Based on the calculated transmitting station angle θ ₂ and the own vehicle traveling angle θ ₁ , the transmitting station direction θ as seen from the own vehicle traveling direction is calculated. A directional antenna having a beam closest to the calculated transmitting station direction θ is selected and connected to a subsequent receiving circuit.

Japanese Patent Application Publication No. 2004-193945

However, in the conventional technology, communication quality may deteriorate because the antenna control is not performed at an optimal cycle depending on the driving condition of the vehicle, and power consumption is caused by excessive antenna control processing. In some cases, it may not be possible to prevent an increase in

For example, according to the configuration of Patent Document 1, antenna control is performed at regular intervals without depending on the driving state of the vehicle, so antenna control timing may be delayed and communication quality may deteriorate, or antenna control processing may be performed excessively. However, there is a problem that the power consumption of the device may increase.

The present invention has been made in view of the problems of the prior art. The purpose of the present invention is to prevent deterioration of communication quality by controlling the antenna at an optimal cycle according to the driving condition of the vehicle, and also to prevent an increase in power consumption of the device due to excessive antenna control processing. The goal is to prevent

A directivity control device according to an aspect of the present invention is a device that controls the directivity of an array antenna mounted on a mobile body, and the device controls the directivity of the array antenna with respect to a target antenna that wirelessly communicates with the array antenna. It is preferable that the vehicle includes a control unit that determines a period in which the moving object is moved, and that the period changes in accordance with a moving state of the moving body.

The controller further includes a relative position detection unit that detects a relative position of the target antenna with respect to the moving object, and the control unit detects the relative position of the target antenna with respect to the moving object detected by the relative position detection unit and the movement. It is preferable that the angular velocities of the array antenna and the target antenna be calculated from the direction of movement of the body, and that the period be set shorter as the angular velocity becomes larger.

The control unit sets, as the threshold value of the angular velocity, a value in which a characteristic value indicating the directivity characteristic of the antenna included in the array antenna by angle is a change amount per unit time, and when the angular velocity exceeds the threshold value. Preferably, the period is set so that the length of the period is shorter than the period when the angular velocity is equal to or less than the threshold value.

The control unit further sets at least one other threshold value when the angular velocity exceeds the threshold value, and further sets at least one other threshold value when the angular velocity is equal to or less than the threshold value, Preferably, the interval between the threshold and the other threshold is set to be shorter than the interval between the threshold and the other threshold.

Preferably, the number of the at least one other threshold value exceeding the threshold value is greater than the number of the at least one other threshold value less than or equal to the threshold value.

The control unit includes a steering angle sensor unit that detects a steering angle of the mobile body, and the control unit calculates the steering angle of the mobile body detected by the steering angle sensor unit, and based on the magnitude of the steering angle, Preferably, the period is changed.

Preferably, the control unit sets the cycle to be shorter as the steering angle is larger.

The controller includes a vehicle speed sensor section that detects the moving speed of the moving object, and the control section calculates the speed of the moving object detected by the vehicle speed sensor section, and adjusts the steering angle based on the magnitude of the speed. It is preferable to further change the set period.

Preferably, the control unit sets the cycle set by the steering angle to be shorter as the speed is higher.

In the directivity control system according to another aspect of the present invention, the directivity control device is mounted on a vehicle, the communication data to be wirelessly communicated is data of an electronic device installed in the vehicle, and Preferably, the wireless device includes a wireless device with a target antenna.

According to the present invention, by performing antenna control at an optimal cycle according to the driving condition of the vehicle, deterioration in communication quality is prevented, and an increase in power consumption of the device due to excessive antenna control processing is prevented. It becomes possible to do so.

It is a block diagram showing an example of a directivity control device concerning this embodiment. FIG. 2 is a schematic diagram showing an example of a relative angle AR between a vehicle equipped with the directivity control device according to the present embodiment and a communication partner device. 2 is a flowchart for explaining an example of the operation of the directivity control device according to FIG. 1. FIG. (a) It is a schematic diagram which shows an example of the positional relationship between the driving state of the vehicle in which the directivity control device based on this embodiment is mounted, and the antenna of the base station as a communication partner apparatus. (b) A schematic diagram showing the relative angle between a vehicle equipped with the directivity control device according to the present embodiment and an antenna of a base station. It is a schematic diagram which shows an example of setting the threshold value of the control period of the directivity control apparatus based on this embodiment. It is a schematic diagram which shows another example of setting the threshold value of the control period of the directivity control apparatus based on this embodiment. FIG. 7 is a schematic diagram illustrating another example of setting the threshold value of the control period of the directivity control device according to the present embodiment. It is a block diagram showing another example of a directivity control device concerning this embodiment. FIG. 7 is a schematic diagram showing another example of the positional relationship between the driving state of a vehicle equipped with the directivity control device according to the present embodiment and the antenna of a base station serving as a communication partner device. 9 is a flowchart for explaining an example of the operation of the directivity control device according to FIG. 8. FIG. 2 is a diagram showing an example of the relationship between the steering angle and the turning radius of a vehicle equipped with the directivity control device according to the present embodiment. FIG. 3 is a schematic diagram showing an example of setting a steering angle threshold value of the directivity control device according to the present embodiment. It is a schematic diagram which shows another example of setting the steering angle threshold value of the directivity control device based on this embodiment. 4 is a flowchart showing an example of details of step S304 in the flowchart of FIG. 3. FIG. 11 is a flowchart showing an example of details of step S1003 and step S1004 in the flowchart of FIG. 10. FIG.

Hereinafter, the directivity control device according to the present embodiment will be described in detail using the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

(Operation example of directional control device)

The directivity control device according to this embodiment can be mounted on a moving object such as a vehicle. In this case, the communication data sent by the transmitting terminal may be information such as sensor information that detects the situation of the mobile object, information that controls the mobile object, information about electronic devices installed on the mobile object, etc. . The directivity control device is characterized by adjusting the directivity of the array antenna at a period corresponding to the moving state of the moving body.

An example of the operation of the directivity control device according to this embodiment will be described with reference to FIGS. 1 to 7.

FIG. 1 is a block diagram of an example of a directivity control device according to this embodiment.

The directivity control device according to this embodiment includes an array antenna 110, an RF section 120, a baseband section 130, a control section 140, a relative position detection section 150, and a storage section 160.

Array antenna 110 is an arrangement of a plurality of antenna elements. Array antenna 110 can obtain desired directivity by controlling the phase and amplitude of the excitation signal of each antenna element.

The RF unit 120 extracts a signal in a necessary frequency band from the received signal received from the array antenna 110, and converts the signal into a baseband signal. Further, the RF section 120 converts the transmission baseband signal generated by the baseband section 130 into a high frequency band used in wireless communication, and amplifies the amplitude of the transmission baseband signal.

The baseband unit 130 executes communication data modulation/demodulation processing, error control, media access control, and the like. Furthermore, the baseband unit 130 executes directivity control of the array antenna based on control parameters input from the control unit 140.

The control unit 140 determines the control parameters and control timing of the antenna directivity based on the relative position of the communication partner device with respect to the host vehicle detected by the relative position detection unit 150. Details of the control timing will be described later.

The relative position detection unit 150 detects the relative position of a communication partner device with respect to the host vehicle. An example of the relative position detection unit 150 is a device such as a vehicle navigation device that can detect a relative position with a communication partner based on GPS, a gyro, or map data.

FIG. 2 shows a schematic diagram of the relative angle between the host vehicle and a communication partner device that is performing wireless communication. A relative position detection unit 150 mounted on the own vehicle receives position information of a communication partner device from the communication partner device, and calculates the own vehicle position information and traveling direction information based on GPS, gyro, and map data. do. Next, the relative position detection unit 150 calculates the relative angle AR with respect to the communication partner device from the position information of the communication partner device and the position information and traveling direction information of the host vehicle.

(Flowchart of operation example of directional control device)
A flowchart of an example of the operation of the directivity control device 100 having the above configuration will be described using FIG. 3.

The flowchart according to the present embodiment assumes wireless communication between a device mounted on a vehicle (vehicle-mounted device) and a device installed outside the vehicle (base station). The on-vehicle device mounted on the vehicle includes the configuration shown in FIG. 1, and has a configuration in which the directivity of the array antenna 110 can be arbitrarily controlled. The directivity of the array antenna 110 is determined, for example, based on the change in the relative angle AR per unit time calculated based on the position information with respect to the communication partner shown in FIG. 2 obtained from the relative position detection unit with respect to the communication partner. That is, the timing for controlling the directivity of the array antenna is adaptively changed based on the angular velocity ω, which is the rate of change of the relative angle AR with respect to the communication partner obtained by the relative position detection unit 150 with respect to the communication partner. do.

Next, details of the flowchart according to this embodiment will be explained.

In step S301, as shown in FIG. 3, the control unit 140 first periodically acquires the relative angle ARn (n is a natural number of 1 or more) with respect to the communication partner obtained from the relative position detection unit 150 with respect to the communication partner. . Here, the cycle may be the minimum data transmission time of communication data between the onboard device and the base station. Further, the period may be a time obtained by dividing the minimum data transmission time of communication data by a positive integer. By setting the period to the above-described time, it becomes possible to control the directivity of the array antenna at appropriate timing and reduce the probability that communication data will not be communicated. Next, the directivity control device 100 proceeds to step S302.

In step S302, the control unit 140 stores the periodically acquired relative angle ARn in the storage unit 160. Next, the directivity control device 100 proceeds to step S303.

In step S303, the control unit 140 calculates a relative Calculate the angular velocity ω, which is the rate of change of the angle. Next, the directivity control device 100 proceeds to step S304.

In step S304, the control unit 140 compares the angular velocity ω with a predetermined threshold value. The directivity control period is determined depending on which range of predetermined threshold values the angular velocity ω falls within (this process may be referred to as BSP determination process). Next, the directivity control device 100 returns to step S301.

(Example of setting threshold for determining directivity control cycle)
Next, the setting of a threshold value for determining the directivity control cycle in the BSP determination process will be explained using an example.

For example, assume that the present invention is applied to a road-vehicle communication system on a highway as shown in FIG. Here, in order to set the threshold value, assume as an example a case where the in-vehicle array antenna is placed at the center of the vehicle in the width direction, and the roadside antenna is installed on the shoulder of the road 5 m from the center of the lane. It is assumed that a vehicle travels at the legal speed of 100 km/h (constant speed) on an expressway, and road-to-vehicle communication is performed with a minimum data transmission time interval of 100 ms.

FIG. 5 shows an example of setting the rate of change of the relative azimuth angle (angular velocity: deg/100 ms) and the threshold value with respect to the traveling position, assuming that the half-value angle of the vehicle-mounted array antenna is 40 degrees. In FIG. 5, the horizontal axis indicates the relative positional relationship between the traveling vehicle and the roadside antenna, and shows a state in which the roadside antenna is located right next to the vehicle at a traveling position of 0 m. When the traveling position is 0 m, the angular velocity is approximately 53 (deg/100 ms), and when the traveling position is ±4 m, the angular velocity is approximately 20 (deg/100 ms).

In the example shown in FIG. 5, the threshold is set to 20 (deg/100ms), which is the rate of change of the relative azimuth that is half the half-value angle of the on-vehicle array antenna. An example is shown in which the low-speed control period is set to . That is, when the angular velocity calculated in step S303 exceeds 20 (deg/100ms), the control cycle of the array antenna 110 is set to high speed, and when the angular velocity is 20 (deg/100ms) or less, the control cycle of the array antenna 110 is set to high speed. Set the control cycle to low speed.

Here, the terms "high speed" and "slow speed" do not indicate specific numerical values or numerical ranges. That is, when the angular velocity exceeds 20 (deg/100 ms), the control cycle of the array antenna 110 is called high speed because it is shorter than when the angular velocity is 20 (deg/100 ms) or less. Further, when the angular velocity is 20 (deg/100 ms) or less, the control period of the array antenna 110 is longer than when the angular velocity exceeds 20 (deg/100 ms), which is referred to as low speed. In this way, by setting 1/2 of the half value angle of the in-vehicle array antenna as the threshold value for the control cycle of the array antenna, when the angular velocity is high, the control cycle is made faster, that is, by shortening the control cycle, communication quality is improved. It becomes possible to maintain the Further, when the angular velocity is slow, the control period is slowed down, that is, the control period is made long, thereby making it possible to reduce the power consumption for controlling the array antenna.

In particular, when the angular velocity exceeds 20 (deg/100 ms), the change in the angular velocity with respect to the traveling distance becomes large, so it may be necessary to further divide the control period into smaller sections. In such a case, as explained in FIGS. 6 and 7, by subdividing the high-speed control period, it becomes possible to appropriately set the control period.

The embodiment of FIG. 6, like the embodiment of FIG. 5, is intended to be applied to a road-to-vehicle communication system on an expressway as shown in FIG. Here, in order to set the threshold value, it is assumed as an example that the in-vehicle array antenna is placed at the center of the vehicle in the width direction, and the roadside antenna is installed on the shoulder of the road 5 m from the center of the lane. It is assumed that a vehicle travels at the legal speed of 100 km/h (constant speed) on an expressway, and road-to-vehicle communication is performed with a minimum data transmission time interval of 100 ms.

In the embodiment shown in FIG. 6, compared to the embodiment shown in FIG. An example of threshold setting when performing detailed antenna control is shown. For example, if the angular velocity interval is 10 (deg/100 ms), the threshold value is set at an interval of 10 (deg/100 ms) based on 20 (deg/100 ms). That is, as shown in FIG. 6, the threshold values are set to 50 (deg/100ms), 40 (deg/100ms), 30 (deg/100ms), 20 (deg/100ms), and 10 (deg/100ms). . When the angular velocity is between 20 (deg/100 ms) and 0 (deg/100 ms), the control cycle of the array antenna 110 is set to a low speed. Further, when the angular velocity is between 20 (deg/100 ms) and the maximum angular velocity of 53 (deg/100 ms), the control period of the array antenna 110 is set to high speed.

When the angular velocity becomes larger than 1/2 of the half-power angle of the vehicle-mounted array antenna, the degree of deterioration of communication quality increases, so it is necessary to promptly change the directivity of the vehicle-mounted antenna. Therefore, when the angular velocity becomes larger than 1/2 of the half value angle of the on-vehicle antenna, it is necessary to shorten the control period of the array antenna. Furthermore, as the angular velocity becomes smaller than 1/2 of the half-value angle of the in-vehicle antenna, the degree of deterioration in communication quality becomes smaller. Therefore, the control period of the array antenna can be made longer to reduce the power consumption for controlling the array antenna. It becomes possible to reduce the

For example, as shown in FIG. 6, when the angular velocity exceeds 20 (deg/100 ms), the control period of the array antenna is set to high speed. The control cycle when the angular velocity is between 30 (deg/100ms) and 40 (deg/100ms) is the same as the control cycle when the angular velocity is between 20 (deg/100ms) and 30 (deg/100ms). Set shorter than the control cycle. Also, the control cycle when the angular velocity is between 40 (deg/100ms) and 50 (deg/100ms) is the same as when the angular velocity is between 30 (deg/100ms) and 40 (deg/100ms). Set shorter than the control cycle. Further, the control cycle when the angular velocity exceeds 50 (deg/100 ms) is set shorter than the control cycle when the angular velocity is between 40 (deg/100 ms) and 50 (deg/100 ms). In this way, as the angular velocity becomes larger than 1/2 of the half-power angle of the onboard antenna, the control period of the array antenna becomes shorter, that is, the control period of the array antenna becomes faster. It becomes possible to reduce quality deterioration.

Furthermore, when the angular velocity is smaller than 1/2 of the half-value angle of the on-vehicle antenna, there is a high possibility that communication quality will be maintained, so the control cycle of the array antenna is made slow in order to reduce power consumption. For example, as shown in Fig. 6, when the angular velocity is between 10 (deg/100ms) and 0 (deg/100ms), the control cycle is as follows: The control cycle is set to a lower speed than the control cycle when it is between.

Furthermore, like the embodiments shown in FIGS. 5 and 6, the embodiment shown in FIG. 7 is also intended to be applied to a road-to-vehicle communication system on an expressway as shown in FIG. Here, in order to set the threshold value, it is assumed as an example that the in-vehicle antenna is placed at the center of the vehicle in the width direction, and the roadside antenna is installed on the shoulder of the road 5 m from the center of the lane. It is assumed that a vehicle travels at the legal speed of 100 km/h (constant speed) on an expressway, and road-to-vehicle communication is performed with a minimum data transmission time interval of 100 ms.

In the embodiment shown in FIG. 7, compared to the embodiment shown in FIG. An example of setting a threshold value when the threshold value interval is set smaller than the rate of change of the azimuth angle is shown.

For example, the threshold values are set to 50, 45, 40, 35, 30, 25, 20, 10 (deg/100ms). In this way, by finely setting the threshold interval when the relative azimuth angle change rate exceeds 1/2 of the half-power angle of the on-vehicle antenna, road-to-vehicle communication can be maintained even when the vehicle is running at high speed. , it becomes possible to suppress deterioration of communication quality.

Specifically, as shown in FIG. 7, when the angular velocity exceeds 20 (deg/100 ms), the control period of the array antenna 110 is set to be high. The control cycle when the angular velocity is between 25 (deg/100ms) and 30 (deg/100ms) is the same as the control cycle when the angular velocity is between 20 (deg/100ms) and 25 (deg/100ms). Set shorter than the control cycle. Furthermore, the control cycle when the angular velocity is between 30 (deg/100ms) and 35 (deg/100ms) is the same as when the angular velocity is between 25 (deg/100ms) and 30 (deg/100ms). Set shorter than the control cycle. Furthermore, the control cycle when the angular velocity is between 35 (deg/100ms) and 40 (deg/100ms) is the same as when the angular velocity is between 30 (deg/100ms) and 35 (deg/100ms). Set shorter than the control cycle. Furthermore, the control cycle when the angular velocity is between 40 (deg/100ms) and 45 (deg/100ms) is the same as that when the angular velocity is between 35 (deg/100ms) and 40 (deg/100ms). Set shorter than the control cycle. Further, the control period when the angular velocity exceeds 50 (deg/100 ms) is set shorter than the control period when the angular velocity is between 45 (deg/100 ms) and 50 (deg/100 ms).

Furthermore, in the embodiment shown in FIG. 7 as well as in the embodiment shown in FIG. In order to reduce this, the control cycle of the array antenna 110 is made slow. For example, as shown in Fig. 7, when the angular velocity is between 10 (deg/100ms) and 0 (deg/100ms), the control cycle is as follows: The control cycle is set to a lower speed than the control cycle when it is between.

In this way, the control period of the array antenna 110 is divided into smaller sections when the angular velocity is larger than 1/2 of the half-power angle of the on-vehicle antenna, compared to when the angular velocity is smaller than 1/2 of the half-power angle of the on-vehicle antenna. , it becomes possible to maintain road-to-vehicle communication and suppress deterioration of communication quality. Furthermore, the control frequency of the array antenna 110 can be increased by increasing the threshold interval when the angular velocity is smaller than 1/2 of the half-value angle of the on-vehicle antenna than when the angular velocity is larger than 1/2 of the half-value angle of the on-vehicle antenna. This makes it possible to reduce power consumption.

Next, an example of the process of determining the directivity control period BSP in step S304 will be described based on FIG. 14. The threshold value determined in step S304 in FIG. 14 is based on the angular velocity in FIG. 6.

In step S304a, it is determined whether the angular velocity is greater than the angular velocity threshold th1 in FIG. If the angular velocity is greater than the angular velocity threshold th1 in FIG. 6 (step S304a: YES), the process advances to step S304b. If the angular velocity is less than or equal to the angular velocity threshold th1 in FIG. 6 (step S304a: NO), the process proceeds to step S304c.

In step S304b, the directivity control period BSP is determined to period 1, which is the minimum period. The minimum cycle indicates the shortest cycle among the directivity control cycles BSP in step S304. Next, the directivity control device 100 proceeds to step S301.

In step S304c, it is determined whether the angular velocity is greater than the angular velocity threshold th2 in FIG. If the angular velocity is greater than the angular velocity threshold th2 in FIG. 6 (step S304c: YES), the process advances to step S304d. If the angular velocity is less than or equal to the angular velocity threshold th2 in FIG. 6 (step S304b: NO), the process advances to step S304e. Note that the processing flow when the angular velocity is the angular velocity threshold th3 and the threshold th4 in FIG. 6 will be omitted.

In step S304d, the directivity control period BSP is determined to be period 2, which is the next shortest period after period 1, which is the minimum period. Next, the directivity control device 100 proceeds to step S301.

In step S304e, it is determined whether the angular velocity is greater than the angular velocity threshold th5 in FIG. If the angular velocity is greater than the angular velocity threshold th5 in FIG. 6 (step S304c: YES), the process advances to step S304f. If the angular velocity is less than or equal to the angular velocity threshold th5 in FIG. 6 (step S304e: NO), the process advances to step S304g.

In step S304f, the directivity control period BSP is determined to be the next longest period n-1 after the maximum period n. The maximum period indicates the longest period among the directivity control periods BSP in step S304. Next, the directivity control device 100 proceeds to step S301.

In step S304g, the directivity control period BSP is determined to be the maximum period n. Next, the directivity control device 100 proceeds to step S301.

(Modified example)
Next, the configuration of a modified example will be explained with reference to FIGS. 8 to 13.

As shown in FIG. 8, the directivity control device 200 includes an array antenna 110, an RF section 120, a baseband section 130, a control section 140, a relative position detection section 150, a vehicle speed sensor section 170, and a steering angle sensor section 180. configured.

Array antenna 110 is an arrangement of a plurality of antenna elements. The array antenna can obtain desired directivity by controlling the phase and amplitude of the excitation signal of each antenna element.

The RF unit 120 extracts a signal in a necessary frequency band from the received signal received from the array antenna, and converts the signal into a baseband signal. Further, the RF section converts the transmission baseband signal generated in the baseband section into a high frequency band used in wireless communication, and amplifies the amplitude of the transmission baseband signal.

The baseband unit 130 executes communication data modulation/demodulation processing, error control, media access control, and the like. Furthermore, the baseband unit 130 executes directivity control of the array antenna based on control parameters input from the control unit 140.

The control unit 140 determines the control parameters and control timing of the antenna directivity based on the relative position with respect to the communication partner, the traveling speed, and the steering angle detected by the relative position detection unit 150. Details of the control timing will be described later.

The relative position detection unit 150 detects the relative position of a communication partner device with respect to the host vehicle. An example of the relative position detection unit 150 is a vehicle navigation device that can detect a relative position with a communication partner based on GPS, a gyro, or map data.

Vehicle speed sensor section 170 detects the traveling speed of the host vehicle.

The steering angle sensor section 180 detects the steering angle (turning angle: steering angle) of the steering wheel of the host vehicle.

(Flowchart of operation example of directional control device)
A flowchart of an operation example of the directivity control device 200 having the above configuration will be described using FIG. 10.

The flowchart according to the present embodiment assumes wireless communication between a device mounted on a vehicle (vehicle-mounted device) and a device installed outside the vehicle (base station). The on-vehicle device mounted on the vehicle has a configuration as shown in FIG. 8, and the directivity of the array antenna 110 can be arbitrarily controlled. The directivity of the array antenna 110 is determined, for example, based on the position information (relative angle AR) with respect to the communication partner shown in FIG. 3 obtained from the communication partner relative position detection unit 150. This embodiment is characterized in that the timing for controlling the directivity of the array antenna 110 is adaptively changed based on the vehicle speed V of the own vehicle obtained from the vehicle speed sensor section 170 and the steering angle A obtained from the steering angle sensor section 180. shall be. Specifically, the control unit 140 first periodically collects the running speed of the host vehicle obtained from the vehicle speed sensor unit 170 and the steering angle (turn angle: steering angle) of the steering wheel obtained from the steering angle sensor unit 180. . Next, the collected speed DS of the host vehicle and the steering angle (turning angle: steering angle) SA of the steering wheel are recorded in the storage unit 160. Thereafter, a basic directivity control period BBSP (Basic BSP) is determined from the magnitude of the recorded steering angle (steering angle: steering angle) SA of the steering wheel. Furthermore, the basic directivity control period BBSP is multiplied by a coefficient corresponding to the speed DS of the host vehicle to determine the directivity control period BSP.

Next, details of the flowchart according to this embodiment will be explained.

In step S1001, as shown in FIG. 8, the control unit 140 periodically changes the speed DS of the host vehicle obtained from the vehicle speed sensor unit 170 and the steering angle (steering angle: steering angle) SA obtained from the steering angle sensor unit 180. to obtain the target. Here, the cycle may be the minimum data transmission time of communication data between the onboard device and the base station. Further, the period may be a time obtained by dividing the minimum data transmission time of communication data by a positive integer. By setting the period to the above-described time, it becomes possible to control the directivity of the array antenna 110 at appropriate timing and reduce the probability that communication data will not be communicated. Next, the directivity control device 200 proceeds to step S1002.

In step S1002, the control unit 140 stores the periodically acquired speed DS of the host vehicle and the steering angle (turn angle: steering angle) SA in the storage unit 160. Next, the directivity control device 200 proceeds to step S1003.

In step S1003, the control unit 140 determines the basic directivity control period BBSP from the magnitude of the steering angle (steering angle: steering angle) SA (this process may be referred to as BBSP determination process). The larger the steering angle (steering angle: steering angle) SA of the steering wheel is, the smaller the basic directivity control period BBSP becomes. When the steering angle (steering angle: steering angle) SA is large, the turning radius of the vehicle becomes small, which may cause a large change in the relative angle AR between the onboard device and the base station while driving straight. There are cases where it is necessary to increase the array antenna control cycle. Next, the directivity control device 200 proceeds to step S1004.

In step S1004, the control unit 140 determines the directivity control period BSP by multiplying the basic directivity control period BBSP by a coefficient corresponding to the speed DS of the host vehicle. The larger the speed DS of the host vehicle is, the smaller the value of the coefficient becomes. That is, as the speed DS of the host vehicle increases, the angular velocity ω may also increase, so it may be necessary to increase the array antenna control period. Next, the directivity control device 200 returns to step S1001.

Next, the setting of a threshold value for determining the directivity control cycle in the BBSP determination process will be explained using an example.

For example, assume application to a road-to-vehicle communication system in an open space as shown in FIG. In such a system, it is expected that cases will frequently occur in which the direction of travel of the vehicle changes significantly with respect to the roadside antenna. Here, in order to set the steering angle threshold value, it is assumed that the vehicle travels at a constant speed with a constant steering angle (turning angle: steering angle) as shown in FIG. In this case, since the steering angle is constant, the vehicle travels in a direction that rotates on the circumference at an angle corresponding to the steering angle.

FIG. 12 shows an example of setting the steering angle threshold value of the steering angle (turning angle: steering angle) based on the normalized turning radius normalized by the minimum turning radius of the vehicle. Note that the relationship between the steering angle and the normalized turning radius may differ depending on the type of vehicle. In this example, the normalized turning radius is divided into equal intervals, and the corresponding steering angle (turn angle: steering angle) is set as the steering angle threshold.

For example, in FIG. 12, steering angles corresponding to normalized turning radius values of 200, 150, 100, and 50 are set as threshold values. For example, when the steering angle is between the steering angle threshold SAth3 and the steering angle threshold SAth4, the basic directivity control period BBSP is smaller than when the steering angle is smaller than the steering angle threshold SAth4. Furthermore, when the steering angle is between the steering angle threshold SAth2 and the steering angle threshold SAth3, the basic directivity control period BBSP is becomes smaller. Further, when the steering angle is larger than the steering angle threshold SAth1, the basic directivity control period BBSP becomes smaller than when the steering angle is between the steering angle threshold SAth1 and the steering angle threshold SAth2. That is, the larger the steering angle, the smaller the basic directivity control period BBSP.

FIG. 13 shows another example of setting the steering angle threshold value of the steering angle (turning angle: steering angle) based on the normalized turning radius normalized by the minimum turning radius of the vehicle. In this example, the smaller the normalized turning radius, the narrower the interval, and the corresponding steering angle (turning angle: steering angle) is set as the steering angle threshold.

For example, in FIG. 13, the steering angles corresponding to normalized turning radius values of 200, 100, 50, 30, 15, and 5 are set as threshold values. For example, when the steering angle is between the steering angle threshold SAth9 and the steering angle threshold SAth10, the basic directivity control period BBSP is smaller than when the steering angle is smaller than the steering angle threshold SAth10. Furthermore, when the steering angle is between the steering angle threshold SAth8 and the steering angle threshold SAth9, the basic directivity control period BBSP is becomes smaller. Furthermore, when the steering angle is between the steering angle threshold SAth7 and the steering angle threshold SAth8, the basic directivity control period BBSP is becomes smaller. Furthermore, when the steering angle is between the steering angle threshold SAth6 and the steering angle threshold SAth7, the basic directivity control period BBSP is becomes smaller. Furthermore, when the steering angle is larger than the steering angle threshold SAth5, the basic directivity control period BBSP becomes smaller than when the steering angle is between the steering angle threshold SAth6 and the steering angle threshold SAth5. That is, the larger the steering angle, the smaller the basic directivity control period BBSP. As described above, FIG. 13 shows an example in which the control period of the array antenna is finely set in a region where the normalized radius of rotation is small, that is, a region where the steering angle is large.

On the other hand, regarding the speed threshold in step S1004, it is assumed that the threshold is set at equal speed intervals, or the threshold is set at a narrower interval as the speed increases. However, as the speed increases, the absolute value of the coefficient becomes smaller and the control period of the array antenna becomes shorter.

Next, an example of the process of determining the basic directivity control period BBSP in step S1003 will be described based on FIG. 15. The steering angle threshold value determined in step S1003 of FIG. 15 is based on the steering angle threshold value of FIG. 12.

In step S1003a, it is determined whether the absolute value of the steering angle is larger than the steering angle threshold value SAth1 in FIG. 12. If the absolute value of the steering angle is larger than the steering angle threshold value SAth1 in FIG. 12 (step S1003a: YES), the process advances to step S1003b. If the absolute value of the steering angle is less than or equal to the steering angle threshold value SAth1 in FIG. 12 (step S1003a: NO), the process advances to step S1003c.

In step S1003b, the basic directivity control period BBSP is determined to be period 1, which is the minimum period. The minimum period indicates the shortest period among the basic directivity control periods BBSP in step S1003. Next, the directivity control device 200 proceeds to step S1004.

In step S1003c, it is determined whether the absolute value of the steering angle is larger than the steering angle threshold value SAth2 in FIG. 12. If the absolute value of the steering angle is larger than the steering angle threshold value SAth2 in FIG. 12 (step S1003c: YES), the process advances to step S1003d. If the absolute value of the steering angle is less than or equal to the steering angle threshold value SAth2 in FIG. 12 (step S1003c: NO), the process advances to step S1003e. In addition, in FIG. 15, the case of steering angle threshold value SAth3 is omitted.

In step S1003d, the basic directivity control period BBSP is determined to be period 2, which is longer than period 1, which is the minimum period. Period 2 indicates the second shortest period among the basic directivity control periods BBSP in step S1003. Next, the directivity control device 200 proceeds to step S1004.

In step S1003e, it is determined whether the absolute value of the steering angle is larger than the steering angle threshold value SAth4 in FIG. 12. If the absolute value of the steering angle is larger than the steering angle threshold value SAth4 in FIG. 12 (step S1003e: YES), the process advances to step S1003f. If the absolute value of the steering angle is less than or equal to the steering angle threshold value SAth4 in FIG. 12 (step S1003e: NO), the process advances to step S1003g.

In step S1003f, the basic directivity control period BBSP is determined to be the next longest period n-1 after the maximum period n (n: natural number). Period n-1 indicates the second longest period among the basic directivity control periods BBSP in step S1003. Next, the directivity control device 200 proceeds to step S1004.

In step S1003g, the basic directivity control period BBSP is determined to be the maximum period n. The maximum period indicates the longest period among the basic directivity control periods BBSP in step S1003. Next, the directivity control device 200 proceeds to step S1004.

Next, an example of the process of determining the coefficient for the basic directivity control period BBSP in step S1004 will be described based on FIG. 15. Note that the speed threshold SPth1, the speed threshold SPth2, and the speed threshold SPthn-1 with respect to the vehicle speed DS have the following relationship. That is, speed threshold SPth1<speed threshold SPth2<speed threshold SPthn-1, and speed threshold SPthn-1 indicates the fastest speed. Further, the speed threshold values may be set at equal speed intervals, or the threshold values may be set at narrower intervals as the speed increases, and the setting of the speed threshold values is not limited here.

In step S1004a, it is determined whether the speed DS of the vehicle is smaller than the speed threshold SPth1. If the speed DS of the vehicle is smaller than the speed threshold SPth1 (step S1004a: YES), the process advances to step S1004b. If the speed DS of the vehicle is equal to or higher than the speed threshold SPth1 (step S1003a: NO), the process advances to step S1004c.

In step S1004b, the coefficient by which the basic directivity control period BBSP is multiplied is determined to be the largest value, ie, the coefficient 1. Coefficient 1 indicates the largest value among the coefficients in step S1004. Next, the directivity control device 200 returns to step S1001.

In step S1004c, it is determined whether the speed DS of the vehicle is smaller than the speed threshold SPth2. If the speed DS of the vehicle is smaller than the speed threshold SPth2 (step S1004c: YES), the process advances to step S1004d. If the speed DS of the vehicle is equal to or higher than the speed threshold SPth2 (step S1003c: NO), the process advances to step S1004d.

In step S1004d, the coefficient by which the basic directivity control period BBSP is multiplied is determined to be coefficient 2, which is the next largest value after coefficient 1 in step S1004. Next, the directivity control device returns to step S1001.

In step S1004e, it is determined whether the speed DS of the vehicle is smaller than the speed threshold SPthn-1. If the speed DS of the vehicle is smaller than the speed threshold SPthn-1 (step S1004e: YES), the process advances to step S1004f. If the speed DS of the vehicle is equal to or higher than the speed threshold SPthn-1 (step S1003e: NO), the process advances to step S1004g.

In step S1004f, the coefficient by which the basic directivity control period BBSP is multiplied is determined to be coefficient n-1, which is the next smallest value after coefficient n in step S1004. The coefficient n is the smallest value in step S1004. Next, the directivity control device 200 returns to step S1001.

Although the embodiments have been described in detail with reference to the drawings, the present invention is not limited to the contents described in the above embodiments. Further, the constituent elements described above include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described above can be combined as appropriate. Further, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

100, 200 directivity control device 110 array antenna 120 RF section 130 baseband section 140 control section 150 relative position detection section 160 storage section 170 vehicle speed sensor section 180 steering angle sensor section

Claims (9)

A device for controlling the directivity of an array antenna mounted on a mobile object,
a control unit that determines a period for controlling the directivity of the array antenna with respect to a target antenna that wirelessly communicates with the array antenna;
a relative position detection unit that detects a relative position of the target antenna with respect to the moving body,
The period changes depending on the moving state of the moving body,
The control unit calculates the angular velocity of the array antenna and the target antenna based on the relative position of the target antenna with respect to the mobile body detected by the relative position detection unit and the moving direction of the mobile body, A directivity control device that sets the period to be shorter as the angular velocity increases . The control unit sets, as the threshold value of the angular velocity, a value in which a characteristic value indicating the directivity characteristic of the antenna included in the array antenna by angle is a change amount per unit time, and when the angular velocity exceeds the threshold value. The directivity control device according to claim 1 , wherein the period is set so that the length of the period is shorter than the period when the angular velocity is equal to or less than the threshold value. The control unit further sets at least one other threshold value when the angular velocity exceeds the threshold value, and further sets at least one other threshold value when the angular velocity is equal to or less than the threshold value, The directivity control device according to claim 2 , wherein an interval between the threshold and the other threshold is set to be shorter than an interval between the threshold and the other threshold. The directivity control device according to claim 3 , wherein the number of the at least one other threshold value exceeding the threshold value is greater than the number of the at least one other threshold value less than or equal to the threshold value. A device for controlling the directivity of an array antenna mounted on a mobile object,
a control unit that determines a period for controlling the directivity of the array antenna with respect to a target antenna that wirelessly communicates with the array antenna;
a steering angle sensor unit that detects a steering angle of the mobile body ,
The period changes depending on the moving state of the moving body,
The control unit is a directivity control device that calculates a steering angle of the mobile object detected by the steering angle sensor unit, and changes the period based on the magnitude of the steering angle. The directivity control device according to claim 5 , wherein the control section sets the cycle to be shorter as the steering angle is larger. including a vehicle speed sensor unit that detects the moving speed of the moving object,
7. The control unit calculates the speed of the moving body detected by the vehicle speed sensor unit, and further changes the cycle set by the steering angle based on the magnitude of the speed. Directional control device as described. The directivity control device according to claim 7 , wherein the control section sets the cycle set by the steering angle to be shorter as the speed is higher. The directivity control device according to any one of claims 1 to 8 is mounted on a vehicle, and the communication data to be wirelessly communicated is data of an electronic device provided in the vehicle, and transmits and receives the communication data. A directivity control system including a wireless device including the target antenna.

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