JP6319211B2 - Information providing device by inter-vehicle communication - Google Patents

Description

  The present invention relates to an information providing apparatus using inter-vehicle communication.

  In order to support driving of vehicles, particularly automobiles, it is becoming practical to provide information on other vehicles obtained by inter-vehicle communication using wireless communication to the driver of the own vehicle. For example, while another vehicle is about to enter the own vehicle travel lane in which the host vehicle is traveling from a side road that is in front of the host vehicle, the other vehicle may be separated from the driver of the host vehicle by an obstacle. It is conceivable to provide information to the driver of the own vehicle that other vehicles are about to enter the own vehicle travel lane when the vehicle cannot be seen.

  When obtaining information on other vehicles by inter-vehicle communication, the quality of wireless communication for performing inter-vehicle communication becomes a problem. In other words, in a traveling vehicle, the communication quality changes from moment to moment, so that there is a case where good communication quality is ensured at a certain timing and information on other vehicles can be provided appropriately. In some cases, the communication quality is poor and information on other vehicles cannot be provided appropriately. Patent Literature 1 discloses that information indicating that communication quality is poor is provided to the driver of the host vehicle, assuming that communication quality is poor when the reception intensity is equal to or less than a predetermined threshold value.

JP 2014-86750 A

  In the device described in Patent Document 1, there is no problem when the reception intensity exceeds or does not exceed the threshold value. In many cases, the provision of information related to the communication quality provided to the driver of the host vehicle is frequently switched, which causes problems such as annoying the driver.

  Here, in order to determine the communication quality, it is conceivable to use a communication quality determination model such as LCR (Level Crossing Rate) or AFD (Average Fade Duration) used in cellular systems such as mobile phones. This LCR is the number of times the received power per unit time falls below the threshold value. AFD is an average time during which received power falls below a threshold value (time when communication is not established). It is determined that the communication quality is worse as both LCR and AFD are larger.

  When the cellular communication quality judgment model as described above is used for inter-vehicle communication as it is, it has been found that even if the host vehicle is at the same position, the situation where the LCR or AFD is significantly different occurs. did. That is, even if the host vehicle is at the same position, if its direction (traveling direction) is different, LCR and AFD will change greatly (for example, a difference of 5 dB from the actual measurement result). It is practically difficult to adopt the determination model as it is for inter-vehicle communication.

  The present invention has been made in view of the circumstances as described above, and the purpose thereof is to provide information related to communication quality provided together with information related to other vehicles with high accuracy without bothering the driver. An object of the present invention is to provide an information providing apparatus using inter-vehicle communication.

In order to achieve the above object, the following solution is adopted in the present invention. That is, as described in claim 1,
A communication means for performing wireless communication with another vehicle;
Information providing means for providing information on another vehicle obtained through the communication means to the driver of the own vehicle;
Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
Driving environment detection means for detecting the driving environment of the host vehicle;
Direction detecting means for detecting the direction of the host vehicle relative to the host vehicle traveling lane in which the host vehicle is traveling;
Radio wave trajectory determining means for determining the direction of radio waves from other vehicles reaching the host vehicle according to the driving environment detected by the driving environment detecting means;
Communication for estimating communication quality by the communication means based on the vehicle speed detected by the vehicle speed detection means, the direction of the radio wave determined by the radio wave locus determination means, and the direction of the host vehicle detected by the direction detection means Quality estimation means;
Communication quality providing means for providing information on the communication quality estimated by the communication quality estimating means by the information providing means;
It is supposed to be equipped with.

According to the above-described solution technique, the communication quality is estimated accurately by taking into account the direction of the host vehicle with respect to the host vehicle travel lane in addition to the vehicle speed and travel environment of the host vehicle. Information regarding communication quality can be appropriately given to the driver. Of course, since the estimated communication quality is not frequently changed in a short time between good and bad, information related to the communication quality provided to the driver is frequently switched as the communication quality changes. By preventing or suppressing such a situation, it is prevented or suppressed from causing trouble to the driver. In addition to the above, it is preferable to obtain a radio wave trajectory (direction of radio wave) that greatly affects the communication quality using the traveling environment and to estimate the communication quality more accurately.

A preferred mode based on the above solution is as described in claim 2 and the following. That is,
The communication quality estimation means estimates the communication quality in consideration of the obtained vehicle speed of the other vehicle when the information on the vehicle speed of the other vehicle can be obtained by the communication means. Correspondence). In this case, it is preferable to estimate communication quality more accurately by taking into account information related to the vehicle speed of other vehicles, and to achieve the effect corresponding to claim 1 more fully. Become.

  When the communication means can obtain information on the vehicle speed of the other vehicle by the communication means, the communication quality estimation means considers the vehicle speed of the other vehicle on the condition that the communication quality estimated without using the vehicle speed of the other vehicle is good. The communication quality is estimated again (corresponding to claim 3). In this case, it is preferable to obtain the effect corresponding to claim 2 while preventing a situation in which the communication quality is estimated using the wrong vehicle speed of the other vehicle.

The radio wave trajectory determining means and a running environment detected by the position information and the traveling environment detection means of the other vehicle that was acquired by the communication means, to determine the trajectory of the radio waves, are then way (claim 4 Correspondence). In this case, it is preferable to estimate the radio wave trajectory more accurately and estimate the communication quality more accurately.

The communication quality providing means provides information on the quality of communication quality together with information on the other vehicle (corresponding to claim 5 ). In this case, the reliability of the information regarding other vehicles can be appropriately determined using the information regarding the communication quality provided.

The communication quality providing means provides the degree of quality of the communication quality estimated by the communication quality estimating means by associating it with the reliability of information related to other vehicles (corresponding to claim 6 ). In this case, it is preferable to provide information related to other vehicles and information related to communication quality in a form of providing information as simple as possible.

  ADVANTAGE OF THE INVENTION According to this invention, the information provision regarding the communication quality provided with the information regarding another vehicle can be performed accurately, without giving a driver troublesomeness.

The figure which shows the example of a control system of this invention. The simplified top view which shows the example of a relationship between the own vehicle and other vehicle in a state with favorable communication quality. The simplified top view which shows the example of a relationship between the own vehicle and other vehicle in a state with bad communication quality. The flowchart which shows the example of control of this invention. The simplified top view which shows the 2nd example of a relationship between the own vehicle and other vehicle in a state with favorable communication quality. The simplified top view which shows the 2nd example of a relationship between the own vehicle and other vehicle in a state with bad communication quality. The flowchart which shows the 2nd example of control of this invention. The flowchart which shows the 3rd example of control of this invention. The figure which compares and shows the estimation result of the communication quality in a conventional model, and an actual measurement result. The figure which compares and shows the estimation result of communication quality in this invention, and an actual measurement result, and shows the case where an estimation error is the largest. The figure which compares and shows the estimation result of communication quality in this invention, and an actual measurement result, and shows the case where an estimation error is the smallest.

  FIG. 1 shows an example of a control system for inter-vehicle communication configured in the host vehicle. In FIG. 1, U is a controller (control unit) configured using a microcomputer. While the controller U receives signals from various devices S1 to S5, the controller U outputs the signals to the display S10 as information providing means. In the controller U, a travel environment used for estimating communication quality is created and stored in advance as a database in the memory (storage means). This database, for example, categorizes various types of radio wave obstructions and radio wave reflection objects such as intersections and buildings around it, and radio waves from the front side of the vehicle V2 reach the host vehicle VB. It will be used as data used to acquire the trajectory. Then, corresponding to the traveling environment stored in this database, the radio wave locus from the other vehicle V2 to the own vehicle VB when the own vehicle VB is oriented along the traveling lane 10 is stored in association with it. doing.

  Said S1 is an antenna used as one component of the communication means for performing wireless communication with other vehicles. A plurality of antennas S1 are set at positions different from each other, and are used for communication in diversity specifications, and are particularly set so that reception sensitivity for radio waves from the front (including diagonally forward) is good. . S2 is a vehicle speed sensor as vehicle speed detection means. S3 is a GPS that acquires position information of the host vehicle, and uses a navigation device. S4 is a camera, which is used to obtain the environment around the host vehicle, particularly in front of it. S5 is a radar (for example, a millimeter wave radar, an infrared radar, etc.) and, like the camera S4, is used to obtain the traveling environment around the host vehicle, particularly in front of it. As the travel environment to be obtained, in addition to the road conditions ahead, the presence of various obstacles (for example, buildings and fences) that interfere with communication with other vehicles is obtained together with the location.

  Next, a specific example of inter-vehicle communication with other vehicles will be described with reference to FIG. First, 10 and 11 are travel lanes, which intersect at an intersection α. The travel lane 10 is a host vehicle travel lane in which the host vehicle VB travels. The traveling lane 11 is in a state where another vehicle V2 is traveling. Each vehicle and VB and V2 are located near the intersection α and are traveling toward the intersection α. Note that there are obstacles such as buildings near the intersection α, particularly between the host vehicle VB and the other vehicle V2, so that the driver of the host vehicle VB cannot see the other vehicle V2.

  In FIG. 2, the host vehicle VB is in the same direction as the direction of the host vehicle travel lane 10 (the same direction), and a good communication quality is ensured with the other vehicle V2. In this case, for example, a display (information provision) that “the system is operating correctly and there is an approaching vehicle from the right” is performed on the display S10 illustrated in FIG. By providing the information on the display S10, the driver of the host vehicle VB recognizes the information that the communication quality is good and the other vehicle V2 is approaching from the right as the other vehicle information with high certainty. Become. A method for determining the communication quality will be described later.

  On the other hand, FIG. 3 is in a state where the host vehicle VB is facing right with respect to the traveling lane 10 to turn right at the intersection α in the same road situation as FIG. It is in a state. At this time, as the display on the display S10, for example, information such as "Cannot receive radio waves correctly. Please pay sufficient attention." The driver of the host vehicle VB can know from the display on the display S10 that the information on the other vehicle V2 is not available because the inter-vehicle communication is not performed well, and turns right with caution. Note that the communication quality in the case of FIG. 2 is good and the communication quality in the case of FIG. 3 is merely an example, and communication is performed depending on the presence of an obstacle near the intersection α, particularly an obstacle that reflects radio waves. Quality changes.

  FIG. 4 is a flowchart showing an example of control by the controller U for determining whether the communication quality is good or bad. This flowchart will be described below. In the following description, Q indicates a step. First, in Q1, the vehicle speed of the host vehicle VB is acquired. Thereafter, in Q2, the traveling environment ahead of the host vehicle VB is obtained based on the signals from the camera S4 and the radar S5 (for example, the shape, size, position, etc. of the radio obstacle or radio reflector).

  In Q3, the radio wave trajectory, that is, the direction of the radio wave reaching the host vehicle VB is acquired according to the acquired traveling environment. That is, the travel environment that most closely approximates the obtained travel environment is selected from the stored contents of the database, and the radio wave locus corresponding to this closest travel environment is acquired (in the database). This is because the driving environment and radio wave trajectory are stored in association with each other). Note that, instead of storing the traveling environment and the radio wave trajectory in association with each other, the radio wave trajectory may be newly obtained from the stored traveling environment by calculation.

  After Q3, in Q4, the traveling direction of the host vehicle VB with respect to the travel lane 10 in which the host vehicle VB is traveling is acquired. The traveling direction of the host vehicle VB is indicated by a rotation angle of 360 degrees clockwise, for example, in a clockwise direction, with the direction along the traveling lane 10 being 0 degrees in plan view.

  After Q4, in Q5, the communication quality is estimated based on the vehicle speed, the radio wave trajectory, and the direction of the host vehicle VB. The estimation of the communication quality can be obtained, for example, by multiplying a function of which the direction (angle) of the host vehicle VB is a parameter by an LCR function that is a conventionally known cellular system model. In the cellular system model LCR, the communication quality is estimated by two elements of the maximum Doppler frequency according to the speed of the moving body and the fading characteristics depending on the environment. It can be considered that the estimation model is corrected by a function having the direction of the host vehicle VB as a parameter. Thereafter, in Q6, the information related to the other vehicle V2 including the communication quality is displayed on the display 10 (for example, display as described in parentheses in FIGS. 2 and 3).

  FIGS. 5 and 6 are the same as those in FIG. 2 in that the host vehicle VB and the other vehicle V2 are traveling toward the intersection α, but FIG. The case where the communication speed is good (the relative speed between the vehicle VB and the other vehicle V2 is slow) is shown, and FIG. 6 shows the case where the vehicle speed of the other vehicle V2 is large (the relative speed is fast) and the communication quality is bad. Is shown.

  The control example in FIG. 7 estimates the communication quality in consideration of the vehicle speed of the other vehicle V2 as shown in FIGS. 7 will be described. The processing of Q11 to Q15 corresponds to the processing of Q1 to Q5 in FIG.

  After Q15, in Q16, it is determined whether or not the communication quality is good in Q15. If YES in Q16, the vehicle speed of the other vehicle (2 is acquired by inter-vehicle communication in Q17. Thereafter, in Q18, the communication quality is estimated again in consideration of the vehicle speed of the other vehicle V2. After Q18 or when NO in Q16, the process of Q19 is performed (corresponding to Q6 in Fig. 4) In this control example, when the vehicle speed information of the other vehicle V2 can be acquired, this other vehicle V2 Therefore, the communication quality is re-estimated in consideration of the vehicle speed of the vehicle, which is preferable for making the finally estimated communication quality more accurate.

  In the control example of FIG. 8, the communication quality is estimated in consideration of the position of the other vehicle V2. Referring to FIG. 8, the processing of Q21 and Q22 corresponds to the processing of Q1 and Q2 of FIG. After Q22, in Q23, the position information of the other vehicle V2 is acquired by inter-vehicle communication. Thereafter, in Q24, the radio wave trajectory reaching the host vehicle VB is acquired from the traveling environment and the position information of the other vehicle V2.

  After Q24, in Q25, the orientation of the host vehicle VB with respect to the travel lane 10 is acquired (corresponding to Q4 in FIG. 4). Thereafter, in Q26, the communication quality is estimated from the trajectory of the radio wave and the direction of the host vehicle VB. Thereafter, the process of Q27 is performed (corresponding to Q6 in FIG. 4). As described above, in this control example, when the position information of the other vehicle V2 can be acquired, the radio wave locus is acquired in consideration of the position information of the other vehicle V2 in addition to the traveling environment. It can be made more accurate. 8, similarly to the control example of FIG. 7, the position information of the other vehicle V <b> 2 is used on the condition that the communication quality estimated without using the position information of the other vehicle V <b> 2 is good. The communication quality may be estimated again.

  Here, FIG. 9 shows an experimental result, and an LCR as an estimation result by a conventional communication quality estimation model (estimation method of communication quality by a known cellular system, which does not consider the direction of the host vehicle VB). Is indicated by a broken line, and the LCR based on the actual measurement result is indicated by a solid line. In the experiment, in a manner as shown in FIG. 2, FIG. 3, FIG. 5, and FIG. Of these, the actual measurement results and the estimation results are the most different. As described above, in the communication quality estimation result that does not take into account the direction of the host vehicle VB, an error of about 5 dB occurs in the case where it is most different from the actual measurement result, which is practically difficult to use for inter-vehicle communication. It will be a thing.

  On the other hand, FIG. 10 and FIG. 11 show the relationship between the estimation result according to the present invention (LCR obtained by estimating the communication quality in consideration of the direction of the host vehicle VB) and the actually measured LCR, respectively. . In the experiment, as in the case of FIG. 9, the position and vehicle speed of the other vehicle V2 are changed variously in the manner as shown in FIGS. 2, 3, 5, and 6, and the vehicle speed, position, A number of experiments were performed with various changes in direction. Of these, the worst estimation result is shown in FIG. 10, and the best estimation result is shown in FIG. As described above, in the communication quality estimation method according to the present invention, when it is the best, it almost coincides with the actual measurement result (see FIG. 11). Only a slight error of about 2 dB occurs (see FIG. 10). Thus, in the present invention, it is easily understood that the estimation error of the communication quality is small and suitable for inter-vehicle communication.

  Although the embodiments have been described above, the present invention is not limited to the embodiments, and appropriate modifications can be made within the scope of the claims. Accurately acquiring (estimating) the radio wave trajectory toward the host vehicle VB greatly affects the estimation of the final communication quality. Therefore, when estimating the communication quality in consideration of the direction of the host vehicle VB, other vehicles It is preferable to use at least one or both of the position of V2 and the vehicle speed. In the embodiment, the other vehicle V2 is intended to enter the host vehicle travel lane 10 from the front side. However, other vehicles such as an approaching vehicle from obliquely behind can be targeted. Information relating to communication quality can be provided not only with information focused on the communication quality itself but also with reliability (confidence) for information relating to other vehicles. Specifically, for example, the message “There is a high possibility that another vehicle will approach from the right due to radio wave conditions” is displayed. This “Large” indicates that the communication quality is good. "Medium" instead of "medium" indicates that the communication quality is medium, and "Low" instead of "Large" indicates that the communication quality is poor (referred to as "the radio wave condition"). You may lose the meaning display). In addition to this, an appropriate mode can be adopted as a mode of providing information related to communication quality. As a communication quality estimation model, instead of calculating the LCR in consideration of the direction of the host vehicle VB, an AFD (Average Fade Duration) may be calculated (the function of the host vehicle VB is a known AFD function). Multiply function with direction). Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable for better driving assistance by providing information about other vehicles.

U: Controller S1: Antenna (for wireless communication)
S2: Vehicle speed sensor S3: GPS
S4: Camera (for driving environment acquisition)
S5: Radar (for driving environment acquisition)
VB: own vehicle V2: other vehicle 10: travel lane (own vehicle travel)
11: Traveling lane (traveling other vehicles)
α: Intersection

Claims (6)

A communication means for performing wireless communication with another vehicle;
Information providing means for providing information on another vehicle obtained through the communication means to the driver of the own vehicle;
Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
Driving environment detection means for detecting the driving environment of the host vehicle;
Direction detecting means for detecting the direction of the host vehicle relative to the host vehicle traveling lane in which the host vehicle is traveling;
Radio wave trajectory determining means for determining the direction of radio waves from other vehicles reaching the host vehicle according to the driving environment detected by the driving environment detecting means;
Communication for estimating communication quality by the communication means based on the vehicle speed detected by the vehicle speed detection means, the direction of the radio wave determined by the radio wave locus determination means, and the direction of the host vehicle detected by the direction detection means Quality estimation means;
Communication quality providing means for providing information on the communication quality estimated by the communication quality estimating means by the information providing means;
A device for providing information by means of inter-vehicle communication. In claim 1,
When the communication quality estimation means can obtain information on the vehicle speed of the other vehicle by the communication means, the communication quality is estimated in consideration of the obtained vehicle speed of the other vehicle. Information providing device. In claim 2,
When the communication means can obtain information on the vehicle speed of the other vehicle by the communication means, the communication quality estimation means considers the vehicle speed of the other vehicle on the condition that the communication quality estimated without using the vehicle speed of the other vehicle is good. An information providing apparatus using vehicle-to-vehicle communication, wherein communication quality is estimated again. In any one of Claims 1 thru | or 3 ,
The radio wave trajectory determining means determines a radio wave trajectory from the position information of the other vehicle obtained by the communication means and the travel environment detected by the travel environment detection means. Information providing device. In any one of Claims 1 thru | or 4 ,
The communication quality providing means provides information related to the quality of communication quality together with information related to the other vehicle. In any one of Claims 1 thru | or 4 ,
The communication quality providing means provides the information quality by means of inter-vehicle communication, wherein the communication quality providing means provides the degree of quality of the communication quality estimated by the communication quality estimation means by associating it with the reliability of information related to other vehicles.

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