JP2015097028A - Inter-vehicle communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inter-vehicle communication device which can preliminarily provide a driver with information about a driving assisting content that can be provided by a driving assisting system on the basis of an inter-vehicle communication.SOLUTION: A first limit point P1 necessary for automatic brake control at an intersection in front of an own vehicle and a second limit point P2 necessary for alarming are obtained from a limit distance database 4. Meanwhile, on the basis of a spatial distribution characteristic of reception power around the intersection in front of the own vehicle that is obtained from a distribution characteristic database 8, an estimated required time required for inter-vehicle communication with other vehicle around the intersection in front of the own vehicle is estimated, an estimated arriving point PA of the other vehicle on a cross road when communication of the inter-vehicle communication is completed, is estimated, and then, the estimated arriving point PA is compared with the first and second limit points P1 and P2 to preliminarily notify the driver of the information about driving assisting content that can be executed.

Description

  The present invention relates to a vehicle-to-vehicle communication device, and more particularly to a vehicle-to-vehicle communication device that enables a driver to be informed in advance of support contents that can be provided by a driving support system.

  In recent years, various driving support technologies using inter-vehicle communication have been developed. For example, in order to avoid encounter collisions at intersections with poor visibility, it is possible to obtain information on other vehicles traveling on the intersection road by inter-vehicle communication and issue a warning to the driver or activate automatic braking. Assistive technologies are being developed.

  Furthermore, the following Patent Document 1 describes a technique for causing a driver to recognize a communication area for inter-vehicle communication by displaying a communication area capable of inter-vehicle communication superimposed on a map.

JP 2011-191814 A

  In a driving support system, a finite amount of time is required from the detection of another vehicle by acquiring information on the position and speed of another vehicle using inter-vehicle communication until the driving support system such as an automatic brake is activated. It takes. In addition, it takes a finite time for the driver to perform the collision avoidance operation after the driving support system warns the driver of the approach of another vehicle. Furthermore, it takes a braking time for the vehicle to stop due to a driving operation by an automatic brake or a driver.

  For this reason, in order to execute the driving support system, a time margin is required from the detection of the other vehicle to the predicted collision time in accordance with the driving support contents such as warning to the driver and activation of the automatic brake. The time allowance corresponds to the allowance for the distance from the detection position of the other vehicle to the predicted collision point if it is multiplied by the vehicle speed of the other vehicle. For example, in order to avoid an encounter collision at an intersection with poor visibility, it is necessary to detect the other vehicle using inter-vehicle communication before the other vehicle enters within a predetermined distance from the intersection.

  By the way, it takes a finite amount of time from the start of inter-vehicle communication with another vehicle that has entered the communicable area for inter-vehicle communication until the information on the other vehicle is acquired and the inter-vehicle communication is completed. The time required from the start of communication of inter-vehicle communication to the completion of communication varies greatly depending on the radio wave condition. Since inter-vehicle communication is performed by packet communication, if the radio wave condition is poor, the packet error rate increases, and the number of times of re-transmission before all information is transmitted increases. As a result, if the radio wave condition is poor, the communication throughput decreases, and the time required from the start of communication to the completion of communication increases.

  The other vehicle is running from the time when the inter-vehicle communication is started until it is completed. As a result, when the required time from the start to the completion of the inter-vehicle communication becomes longer, another vehicle approaches the intersection during that time, and the margin of distance for operating the driving support system decreases.

  For example, when communication is completed, if the other vehicle has not yet passed the intersection, but is already approaching the intersection, even if the driving support system issues a warning to the driver, the driver's driving avoidance operation is not in time It can happen. Further, when the other vehicle is approaching the intersection at the time of completion of communication, even the automatic brake operation by the driving support system may not be in time.

  On the other hand, a driver who is driving a vehicle equipped with a driving assistance system usually detects the other vehicle and issues a warning or activates an automatic brake so that the driving assistance system avoids an encounter collision at an intersection. I hope that.

  However, it takes time for inter-vehicle communication, and when the communication is completed, the other vehicle has come close to the intersection, so the operation of the automatic brake by the driving support system may not be in time. In that case, the reliability of the driving support system is impaired.

  Further, when another vehicle is already approaching the intersection when the inter-vehicle communication is completed, the warning may not be in time, and only the automatic brake may operate without warning. For example, when the host vehicle is temporarily stopped due to an effort at an intersection, only the automatic brake operates without warning and the start is suppressed. In that case, the driver who does not visually recognize the other vehicle suspects that the vehicle has failed, and reduces the acceptability of the driving support system.

  Thus, the content of the driving assistance that can be provided differs depending on the point where the other vehicle on the cross road reaches when the inter-vehicle communication is completed. On the other hand, the driver always expects the same driving assistance to be performed. For this reason, when the time required for inter-vehicle communication becomes long, a discrepancy occurs between the driving support content that the driver expects from the driving support system and the driving support content that is actually provided by the driving support system. In order to eliminate the discrepancy caused by such inter-vehicle communication, it is desirable to notify the driver of the driving support contents that the driving support system can provide.

  Accordingly, an object of the present invention is to provide an inter-vehicle communication device that enables a driver to be provided in advance with information about driving support contents that can be provided by a driving support system based on inter-vehicle communication.

  In order to achieve the above object, the inter-vehicle communication device of the present invention is configured so that another vehicle on an intersection road detected by inter-vehicle communication is detected from the intersection in order to implement the first driving support content of the driving support system in the own vehicle. A limit point database that stores the first limit point on the intersection road that is separated from the intersection by the first minimum distance that is set as the distance that needs to be at least separated in correspondence with each intersection, and map information An intersection specifying means for specifying an intersection ahead of the host vehicle, a limit point acquiring means for acquiring a first limit point at the specified intersection ahead of the host vehicle from the limit distance database, and an intersection ahead of the host vehicle A distribution characteristic estimation means for estimating a spatial distribution characteristic of received power around the vehicle, and an intersection ahead of the host vehicle based on the estimated spatial distribution characteristic of received power Required time estimation means for estimating an estimated time required for inter-vehicle communication with another vehicle that has entered a communication area for nearby vehicle-to-vehicle communication, and other on the intersection road when communication for inter-vehicle communication is completed based on the estimated required time Arrival point estimation means for estimating an estimated arrival point of the vehicle, and information indicating that the first driving support content is not performed when the estimated arrival point is in a section closer to the intersection than the first limit point. And pre-providing means for providing the driver in advance.

  As a result of diligent research, the inventors of the present application have found the characteristics of the spatial distribution characteristics of received power, which is a physical phenomenon that determines the communication throughput of inter-vehicle communication. The present invention has been made based on such new findings.

  The communication throughput of inter-vehicle communication is determined by the packet error rate. The packet error rate can be determined by the spatial distribution characteristic of the received power. In a vehicle-to-vehicle communication environment, the spatial distribution characteristics of received power vary depending on various factors such as the driving environment of the vehicle such as the width of the road, the arrangement, shape and material of buildings around the road, and the vehicle position.

  Therefore, in the present invention, the communication throughput (required time) of inter-vehicle communication at the intersection is estimated by estimating in advance the spatial distribution characteristics of the received power around the intersection in front of the host vehicle. This estimated communication throughput can be obtained in advance without actually performing inter-vehicle communication with other vehicles on the intersection road.

  Since the estimated communication throughput can be acquired in advance, for example, the estimated arrival point on the intersecting road of the other vehicle when the communication of the inter-vehicle communication is completed is estimated by multiplying the estimated vehicle speed of the other vehicle traveling on the intersecting road. In this way, the estimated arrival point is estimated from the spatial distribution characteristic of the received power.

  On the other hand, in the present invention, in order to implement the first driving support content of the driving support system in the own vehicle, the other vehicle on the intersection road detected by the inter-vehicle communication needs to be at least away from the intersection. The first limit point on the intersection road away from the intersection ahead of the host vehicle is set by the first minimum distance set in the above. This first limit point is set for each intersection.

  In the present invention, when the estimated arrival point and the first limit point are compared, and the estimated arrival point is in a section closer to the intersection than the first limit point, the first driving support content is not performed. Providing information to the driver in advance. For example, when the first driving support content is automatic brake control, the driver is notified in advance that automatic brake control is not performed at an intersection ahead of the host vehicle.

  Thus, according to the present invention, it is possible to provide the driver with information about the driving support contents that can be provided by the driving support system based on the inter-vehicle communication. Thereby, it can suppress that the discrepancy resulting from the vehicle-to-vehicle communication occurs between the driving support content that the driver expects from the driving support system and the driving support content that is actually provided by the driving support system. As a result, it is possible to prevent a decrease in reliability and acceptability of the driving support system.

In the present invention, it is preferable that the distribution characteristic database further stores a spatial distribution characteristic of received power around the intersection in association with each intersection, and the distribution characteristic estimation unit is configured to receive the front of the host vehicle from the distribution characteristic database. The spatial distribution characteristic of the received power around the intersection in front of the host vehicle is estimated by acquiring the spatial distribution characteristic of the received power around the intersection.
Thus, if the spatial distribution characteristics of the received power are mapped in advance for each intersection, the spatial distribution characteristics of the received power at the intersection ahead of the host vehicle can be easily obtained.

In the present invention, it is preferable that the first driving assistance content is automatic brake control.
Thereby, when the estimated arrival point is in a section closer to the intersection than the first limit point, the driver is notified in advance that automatic brake control is not performed at the intersection ahead of the host vehicle.

  In addition, in the present invention, preferably, the limit point database has a minimum distance from the intersection when another vehicle on the intersection road detected by inter-vehicle communication is used in order to implement the second driving assistance content of the driving assistance system. A second limit point on the intersection road that is separated from the intersection by the second minimum distance set as a distance that needs to be stored is stored in association with each intersection, and the second minimum distance is the first minimum distance. Is set to be longer than the minimum distance, and when the estimated arrival point is in a section between the first limit point and the second limit value, the second driving support content is set. Information indicating that there is a possibility of implementing the first driving support content is provided to the driver in advance.

  As a result, when the estimated arrival point is compared with the first and second limit points, and the estimated arrival point is in the section between the first limit point and the second limit point, the second driving support content The driver is provided in advance with information that there is a possibility of implementing the first driving assistance content without carrying out the operation. For example, when the first driving support content is automatic brake control and the second driving support content is warning, automatic braking control may be performed without warning at an intersection ahead of the host vehicle. Is notified to the driver in advance.

  As a result, the driver can be provided in advance with information about driving support contents that can be provided by the driving support system based on inter-vehicle communication. Thereby, it can suppress that the discrepancy resulting from the vehicle-to-vehicle communication occurs between the driving support content that the driver expects from the driving support system and the driving support content that is actually provided by the driving support system. As a result, it is possible to prevent a decrease in reliability and acceptability of the driving support system.

In the present invention, it is preferable that the second driving support content is a warning for notifying an approach of another vehicle on an intersection road ahead of the host vehicle.
As a result, when the estimated arrival point is in the section between the first limit point and the second limit point, for example, automatic brake control is performed at the intersection ahead of the host vehicle without warning of the approach of another vehicle. The driver is notified in advance that there is a possibility of being performed.

In the present invention, it is preferable that the advance provision unit provides information when the host vehicle is temporarily stopped before the intersection.
As a result, for example, in a host vehicle that is temporarily stopped at an intersection, even if only the automatic brake of the driving support system operates without warning and the host vehicle does not start, Since the information indicating that there is a possibility of occurrence of the problem is provided, it is possible to prevent the reliability and acceptability of the driving support system from being lowered.

  As described above, according to the inter-vehicle communication device of the present invention, it is possible to provide the driver with information about the driving support contents that can be provided by the driving support system based on the inter-vehicle communication.

It is a block diagram explaining the structure of the vehicle-to-vehicle communication apparatus by embodiment of this invention. It is a schematic diagram which shows the 1st and 2nd limit point according to the driving assistance content on an intersection road. It is a schematic diagram which shows the communication start point and communication completion point of communication between vehicles of the other vehicle which drive | works toward an intersection on an intersection road. (A) is a graph which shows the relationship between SNR and the packet error rate by the spatial distribution characteristic of reception power, (b) is a graph which shows the relationship between a packet error rate and a throughput. (A) And (b) is a schematic diagram which shows the example of the estimated arrival point of the other vehicle on the cross road at the time of the completion of communication of vehicle-to-vehicle communication. It is a flowchart explaining the operation example of the inter-vehicle communication apparatus of embodiment of this invention.

Hereinafter, an embodiment of an inter-vehicle communication device of the present invention will be described with reference to the accompanying drawings.
First, the configuration of the vehicle-to-vehicle communication device of this embodiment will be described with reference to the block diagram of FIG. In addition, in the block diagram of FIG. 1, illustration of the block of the basic function of vehicle-to-vehicle communication is abbreviate | omitted.

  As shown in FIG. 1, the inter-vehicle communication device of the present embodiment includes an intersection specifying unit 2 that specifies an intersection ahead of the host vehicle based on map information, and first and second limit points on the intersection road for each intersection. The limit point database 4 stored in association with the limit point, the limit point acquisition unit 6 for acquiring the first and second limit points at the specified intersection ahead of the host vehicle from the limit distance database 4, and the received power around the intersection A distribution characteristic database 8 that stores the spatial distribution characteristics of each intersection in association with each other, a distribution characteristic estimation unit 10 that acquires the spatial distribution characteristics of received power around the intersection in front of the host vehicle from the distribution characteristic database 8, and an estimation Based on the spatial distribution characteristics of the received power, the estimated required time required for inter-vehicle communication with another vehicle that has entered the communication area for inter-vehicle communication near the intersection in front of the host vehicle is calculated. A required time estimation unit 12 to be determined, a destination point estimation unit 14 that estimates an estimated destination point PA of another vehicle on the crossing road at the time of completion of communication between vehicles, and an estimated destination point PA. The pre-providing unit 16 compares the first and second limit points P1 and P2 and provides the driver with information on the details of the driving assistance that can be performed.

  The processing functions of the limit point acquisition unit 6, the distribution characteristic estimation unit 10, the required time estimation unit 12, the arrival point estimation unit 14, and the advance provision unit 16 are, for example, a computer such as an ECU (electric control unit). This is realized by executing a predetermined program in (1).

  The intersection specifying unit 2 may be configured using a car navigation unit based on GPS (global positioning system).

  FIG. 2 shows an example of the first limit point and the second limit point on the intersection road of the intersection stored in the limit point database 4. FIG. 2 shows a first limit point P1 and a second limit point P2 for another vehicle V1 that travels from the left side of the drawing toward the intersection I0 on the intersection road R1 of the intersection I0 in front of the host vehicle V0.

  The first minimum distance L1 is set as the distance that the other vehicle V1 on the intersection road R1 detected by inter-vehicle communication needs to be at least away from the intersection I0 when the automatic brake is operated by the driving support system of the own vehicle. The Then, the first limit point P1 is set at a position on the intersection road R1 that is separated from the intersection I0 by the first minimum distance L1.

  For example, it is assumed that the other vehicle V1 travels on the intersection road R1 at a speed of 70 km / h. In this case, the delay time of the system from when the driving support system of the own vehicle detects the other vehicle V1 via inter-vehicle communication until the automatic brake is activated is 0.3 seconds, and further, the delay time due to inter-vehicle communication Assuming 0.1 seconds, 70 × (1000/3600) × (0.3 + 0.1) ≈8 (m). Therefore, the first minimum distance L1 is set to 8 m, and the first limit point P1 is set to a point 8 m before the intersection I0 on the intersection road R1.

In addition, when issuing a warning to notify the approach of another vehicle on the intersection road ahead of the own vehicle by the driving support system in the own vehicle, the other vehicle on the intersection road detected by inter-vehicle communication is at least separated from the intersection. The second minimum distance L2 is set as the distance that needs to be present. Then, a second limit point P2 is set at a position on the intersection road that is separated from the intersection I0 by the first minimum distance L2.
The second minimum distance L2 is set longer than the first minimum distance L1. Therefore, the second limit point P2 is set at a position farther from the intersection than the first limit point P1.

  For example, it is assumed that the other vehicle V1 travels on the intersection road R1 at a speed of 70 km / h. In this case, the delay time of the system from when the driving support system of the own vehicle detects the other vehicle V1 through the inter-vehicle communication until it issues a warning to the driver of the own vehicle is 0.3 seconds, and the driver receives the warning. If the reaction time after 3.7 seconds and the delay time due to inter-vehicle communication is 0.1 seconds, then 70 × (1000/3600) × (0.3 + 3.7 + 0.1) ≈80 (m) . Accordingly, the second minimum distance L2 is set to 80 m, and the second limit point P2 is set to a point 80 m before the intersection I0 on the intersection road R1.

  In setting the first and second limit points P1 and P2, the vehicle speed of the other vehicle V1 may be, for example, the legally limited speed of the intersection road, or based on the measurement result of the vehicle speed of the vehicle traveling on the intersection road. You may decide.

  In FIG. 2, the first and second minimum distances L1 and L2 are represented by the distance from the center point of the intersection I0, but the reference point of the intersection is not limited to this. For example, the first and second minimum distances L1 and L2 may be represented by the distance from the temporary stop line on the intersection road.

  Next, FIG. 3 shows an example of an estimated arrival point on the intersection road R1. FIG. 3 shows an estimated arrival point PA for the other vehicle V1 that travels from the left side of the drawing toward the intersection I0 on the intersection road R1 of the intersection I0 ahead of the host vehicle C0. The estimated arrival point PA is a position that is close to the intersection by a distance L from the communication start point PS that starts the inter-vehicle communication with the other vehicle V1 that has entered the inter-vehicle communication area near the intersection in front of the host vehicle. .

  The communication start point PS is, for example, a point that enters the communication area of another vehicle, and can be obtained as described in Patent Document 1, for example. Also, the communication start point PS for each intersection may be stored in the limit point database 4 and read according to the position of the host vehicle.

  The distance L between the communication start point PS and the communication completion point PA is obtained by the product of the required time Δt required for inter-vehicle communication between the own vehicle and another vehicle on the cross road and the vehicle speed v of the other vehicle. . The vehicle speed v of the other vehicle may be, for example, the legally limited speed of the intersection road, or may be determined based on the measurement result of the vehicle speed of the vehicle traveling on the intersection road.

  The required time Δt for inter-vehicle communication is obtained based on the packet error rate for inter-vehicle communication. Here, FIG. 4A schematically shows the relationship between the packet error rate and the throughput. In FIG. 4A, the horizontal axis represents the packet error rate (PER), and the vertical axis represents the inter-vehicle communication throughput. As indicated by the solid line I in FIG. 4A, the higher the packet error rate (PER), the greater the number of transmission retransmissions, and thus the lower the throughput. That is, the required time Δt becomes longer as the packet error rate (PER) becomes higher.

  The packet error rate (PER) is obtained based on the spatial distribution characteristics of received power. Here, FIG. 4B schematically shows the relationship between the packet error rate (PER) and the SN ratio (SNR). The horizontal axis in FIG. 4B represents the SN ratio (SNR), and the vertical axis represents the packet error rate (PER). A solid line I in FIG. 4B indicates a case where the probability density function representing the spatial distribution characteristic of the received power is assumed to follow the Rayleigh distribution model, and other broken lines II to IV represent the spatial distribution characteristic of the received power. The case where it is assumed that the probability density function follows the Nakagami m distribution model is shown.

  Here, the Rayleigh distribution model is expressed by the following equation (1), and the Nakagami m distribution model is expressed by the following equation (2).

  Here, γ represents SNR, Γ () represents a digamma function, and m represents a parameter representing the degree of fading.

  The Rayleigh distribution model is a distribution model established as a probability density function expressing the spatial distribution characteristics of received power when the transmitting antenna and the receiving antenna are in a positional relationship that cannot be seen from each other in the field of radio waves.

  By the way, the spatial distribution characteristic of the received power near the intersection as the inter-vehicle communication environment varies depending on various factors such as the driving environment of the vehicle such as the width of the road, the arrangement, shape and material of the buildings around the road, and the vehicle position. For this reason, the relationship between the packet error rate (PER) and the SN ratio (SNR) in inter-vehicle communication may not be uniquely determined as in the case of using the Rayleigh distribution model. May not be expressed accurately.

  Therefore, as a result of earnest research, the inventors of the present application have found that the relationship between the packet error rate (PER) and the SN ratio (SNR) in inter-vehicle communication is based on the Nakagami m model. It was found that it can be expressed with higher accuracy than when the model is assumed to be followed. Therefore, it is more desirable to express the probability density function of the spatial distribution characteristic of received power using the Nakagami m model rather than using the Rayleigh distribution model.

  Thus, if the spatial distribution characteristic of the received power around the intersection is known in advance, the communication completion point PA of the inter-vehicle communication can be estimated in advance based on the spatial distribution characteristic.

Further, the advance providing unit 16 compares the estimated arrival point PA with the set first and second limit points P1 and P2. Then, according to the comparison result, information on the driving support contents that can be provided by the driving support system based on the inter-vehicle communication is provided to the driver in advance.
The provision of information to the driver in advance may be performed by voice through a speaker or may be performed by display on a display.

  Here, FIG. 5 shows an example of the positional relationship between the estimated arrival point of the other vehicle on the intersection road and the first and second limit points when the communication of the inter-vehicle communication is completed. When the estimated arrival point PA1 is located in the section S1 between the first limit point P1 and the intersection, information indicating that automatic brake control is not performed at the intersection ahead is provided to the driver in advance. Such advance information increases the driver's awareness of safe driving and can improve traffic safety.

  In addition, when the estimated arrival point PA is located in the section S2 between the first limit point P1 and the second limit point P2, automatic brake control is performed without warning the approach of another vehicle on the cross road. Information that it may be implemented is provided to the driver in advance. As a result, for example, even when only the automatic brake of the driving support system operates without warning and the own vehicle that is temporarily stopped at the time of intersection does not start, the driver has a situation in advance. Since information indicating that there is a possibility is provided, it is possible to prevent a decrease in reliability and acceptability of the driving support system.

Next, an operation example of the vehicle-to-vehicle communication device of this embodiment will be described with reference to the flowchart of FIG.
First, the intersection identification unit 2 identifies an intersection I0 ahead of the host vehicle based on the map information (S1).

  Next, the limit point acquisition unit 6 acquires from the limit distance database 4 a first limit point P1 for automatic brake control and a second limit point P2 for warning at an intersection I0 ahead of the host vehicle (S2). ).

  Next, the distribution characteristic estimation unit 10 acquires the spatial distribution characteristic of the received power around the intersection I0 ahead of the host vehicle from the distribution characteristic database 8 (S3). Subsequently, based on the spatial distribution characteristic of the received power, the required time estimation unit 12 calculates an estimated required time Δt required for the inter-vehicle communication with the other vehicle V1 that has entered the inter-vehicle communication area near the intersection I0 ahead of the host vehicle. Estimate (S4). Furthermore, the arrival point estimation part 14 estimates the estimated arrival point PA of the other vehicle V1 on the intersection road R1 at the time of completion of communication of vehicle-to-vehicle communication based on the estimated required time Δt (S5).

  Next, the advance provision unit 16 compares the estimated arrival point PA with the set first and second limit points P1 and P2. First, it is determined whether it is located in the section S1 between the first limit point P1 and the intersection (PA <P1) (S6). As a result of the determination, if the estimated arrival point PA is closer to the intersection I0 than the first limit point P1 and is located in the section S1 (in the case of “Yes” in S6), the driver will not operate the automatic brake at the intersection I0 ahead. Is notified (S7). In this case, even if the other vehicle V1 is actually detected on the intersection road R1, the automatic brake control is not performed.

  As a result of the comparison in step S5, if the estimated arrival point PA is not closer to the intersection I0 than the first limit point P1 (in the case of “No” in S6), the estimated arrival point PA is the first limit point P1 and the first limit point P1. It is determined whether it is included in the section S2 between the two limit points P2 (P1 ≦ PA <P2) (S8). As a result of the determination, if the estimated arrival point PA is included in the section S2 (“Yes” in step S7), automatic braking control is performed without warning the driver of the approach of the other vehicle V1 on the intersection road R1. It is foretold that it can be done (S9). In this case, when the other vehicle V1 is actually detected on the intersection road R1 (in the case of “Yes” in S10), the automatic brake operates without warning (S11).

  Further, as a result of the comparison in step S8, when the estimated arrival point PA is not included in the section S2 (in the case of “No” in S8), the estimated arrival point PA is a section farther from the intersection I0 than the second limit point P2. Located in S3 (P2 ≦ PA). In this case, the driving support system performs normal driving support content. That is, when the other vehicle V1 is actually detected on the intersection road R1 (in the case of “Yes” in S12), driving assistance such as warning and automatic braking is executed as usual (S13).

  In this way, although the drive support content that can be provided differs depending on the estimated arrival position of the other vehicle at the time of completion of the communication between vehicles, the driver support content that can be provided is notified to the driver in advance. As a result, the driving support content that the driver expects from the driving support system can be matched with the driving support content that is actually provided by the driving support system. As a result, it is possible to prevent a decrease in reliability and acceptability of the driving support system.

  In each embodiment mentioned above, although the example which constituted the present invention on specific conditions was explained, the present invention can perform various change and combination, and is not limited to this. For example, in the above-described embodiment, the example of using the received power spatial distribution characteristic data for each intersection stored in the database in advance has been described. However, in the present invention, the received power spatial distribution characteristic estimation method is used. For example, the calculation model of the spatial distribution characteristic of the received power may be given to the control unit, and the spatial distribution characteristic of the received power around the intersection ahead of the host vehicle may be calculated in real time. Further, in the above-described embodiment, in order to facilitate understanding of the invention, an example in which the host vehicle is stopped at the stop line before the intersection has been described, but the present invention is directed toward the intersection. The present invention can also be applied when traveling.

2 Intersection identification part 4 Limit point database 6 Limit point acquisition part 8 Distribution characteristic database 10 Distribution characteristic estimation part 12 Time required estimation part 14 Arrival point estimation part 16 Advance provision part

Claims (6)

An intersection identifying means for identifying an intersection in front of the host vehicle based on map information;
In order to implement the first driving support content of the driving support system in the own vehicle, the first minimum set as the distance that other vehicles on the intersection road detected by inter-vehicle communication need to be at least away from the intersection A limit point database that stores a first limit point on the intersection road that is separated from the intersection by a distance, in association with each intersection;
Limit point acquisition means for acquiring a first limit point at the specified intersection ahead of the host vehicle from the limit distance database;
A distribution characteristic estimation means for estimating a spatial distribution characteristic of received power around an intersection in front of the vehicle;
Based on the estimated spatial distribution characteristics of received power, a required time estimating means for estimating an estimated required time for inter-vehicle communication with another vehicle that has entered a communication area for inter-vehicle communication near an intersection ahead of the host vehicle;
Based on the estimated required time, arrival point estimation means for estimating an estimated arrival point of another vehicle on the cross road at the time of communication completion of inter-vehicle communication;
In the case where the estimated arrival point is in a section closer to the intersection than the first limit point, a pre-providing means for providing in advance to the driver information indicating that the first driving support content is not performed;
A vehicle-to-vehicle communication device comprising: A distribution characteristic database that stores spatial distribution characteristics of received power around intersections in association with each intersection;
The distribution characteristic estimation means obtains the spatial distribution characteristic of the received power around the intersection ahead of the host vehicle by obtaining the spatial distribution characteristic of the received power around the intersection ahead of the host vehicle from the distribution characteristic database. presume,
The inter-vehicle communication device according to claim 1. The first driving support content is automatic brake control.
The vehicle-to-vehicle communication device according to claim 1 or 2. In order to implement the second driving support content of the driving support system, the limit point database is set as a distance at which other vehicles on the intersection road detected by inter-vehicle communication need to be at least away from the intersection. A second limit point on the intersection road that is separated from the intersection by a minimum distance of 2 is stored in association with each intersection;
The second minimum distance is set to be longer than the first minimum distance;
The pre-providing means does not execute the second driving support content when the estimated arrival point is within a section between the first limit point and the second limit value, Providing the driver in advance with information that there is a possibility of implementing the driving assistance content of 1
The inter-vehicle communication device according to any one of claims 1 to 3. The second driving support content is a warning for notifying the approach of another vehicle on the intersection road in front of the own vehicle.
The inter-vehicle communication device according to claim 4. The advance providing means provides information when the host vehicle is temporarily stopped before an intersection;
The inter-vehicle communication device according to any one of claims 1 to 5.

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