JP2012027698A - Road-vehicle communication device, road-vehicle communication system and road-vehicle communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road-vehicle communication device capable of reliably preventing the missing of positional information.SOLUTION: A road-vehicle communication device 300 which informs a position of an object moving on a road to an on-vehicle device 400, comprises: a data receiving section 310 that obtains measured position of the object; a vehicle position prediction section 330 that obtains a prediction position of the object based on a predetermined movement pattern; a prediction error determination section 340 that determines whether an error of prediction position with respect to the measured position is within a predetermined range; and a data transmission section 360 that, when the error is out of the predetermined range, transmits a piece of information which represents the measured position to the on-vehicle device 400; and when the error is within the predetermined range, a piece of information which represents that the error is within the predetermined range in place of the measured position to the on-vehicle device 400.

Description

  The present invention relates to a road-to-vehicle communication device, a road-to-vehicle communication system, and a road-to-vehicle communication method for notifying an in-vehicle device of the position of an object moving on a road.

  Development of a so-called infrastructure-coordinated safe driving support system that supports safe driving of a vehicle by transmitting information from a device installed at various places on a road to an in-vehicle device is progressing. An example of an infrastructure-coordinated safety driving support system is DSSS (driving safety support systems) that the National Police Agency is promoting.

  In DSSS, a vehicle detector installed on the roadside detects a vehicle traveling on the road periodically (for example, at an interval of 100 milliseconds), and vehicle position information indicating the position of the vehicle is communicated between the roadside and the vehicle installed on the roadside. Send to device. The road-to-vehicle communication device broadcasts the received vehicle position information to an in-vehicle device mounted on the same vehicle traveling on the road or another vehicle. Wireless communication such as DSRC (dedicated short range communication) is used for communication between the road-vehicle communication device and the in-vehicle device (hereinafter referred to as “road-vehicle communication”). The in-vehicle device notifies the driver or the like of the position information of another vehicle, for example, based on the received vehicle position information.

  In DSSS, the vehicle position information includes a vehicle identifier, a position, a speed, and a traveling direction as data items. Accordingly, the data size of each vehicle position information is 16 bytes when 4 bytes, 8 bytes, 2 bytes, and 2 bytes are assigned to each vehicle identifier, for example, vehicle identifier, position, speed, and traveling direction. . When a plurality of vehicles are detected, vehicle position information for the number of detected vehicles is transmitted. Therefore, when all the detection results are transmitted to the in-vehicle device, the vehicle position information has a data size obtained by multiplying 16 bytes by the number of detections for each detection cycle. When the detected number is small with respect to the communication band of road-to-vehicle communication per detection cycle, the road-to-vehicle communication apparatus can transmit all of the detection results.

  However, in recent years, the range in which vehicles are detected is expanding due to the improvement in performance of vehicle detectors. Along with this, the number of detected vehicles increases, and the total data size of vehicle position information to be transmitted (hereinafter referred to as “road-to-vehicle communication data size”) is expected to increase. In addition, the number of detected vehicles generally increases on roads with many lanes. For example, when 200 vehicles are detected in a certain detection cycle, the road-to-vehicle communication data size is 3200 bytes (16 bytes × 200). Therefore, the communication band (for example, 1 Mbps) allocated to road-to-vehicle communication may be compressed by the vehicle position information.

  Therefore, for example, Patent Document 1 and Patent Document 2 describe a technique for preventing compression of road-to-vehicle communication based on vehicle position information. The technology described in Patent Literature 1 excludes a part of data items transmitted by the road-to-vehicle communication device from the transmission target when the communicable time between the road-to-vehicle communication device and the in-vehicle device is short. The technique described in Patent Document 2 sets priority for data items transmitted by the road-to-vehicle communication device, and appropriately excludes data items with low priority from transmission targets. According to these techniques, the road-vehicle communication data size can be suppressed, and the communication band assigned to road-vehicle communication by the vehicle position information can be prevented from being compressed.

JP 2004-54369 A Japanese Patent Laid-Open No. 10-247298

  However, in the techniques described in Patent Literature 1 and Patent Literature 2, since any one of the data items must be excluded from the transmission target, there is a possibility that the vehicle position information to be acquired by the in-vehicle device may be lost.

  Therefore, in order to reduce the road-to-vehicle communication data size, it is conceivable to select and transmit the vehicle that is the object of the vehicle position information. However, in this case, although the vehicle detector detects, for example, 200 vehicles, the in-vehicle device can acquire only the vehicle position information for 100 vehicles, for example. Alternatively, a situation may occur in which the in-vehicle device cannot acquire the traveling direction information among the data items of the vehicle position information. Therefore, there is still a possibility that the vehicle position information to be acquired by the in-vehicle device may be lost.

  Therefore, in the prior art, if vehicle position information is lost, there is a possibility that safe driving of the vehicle cannot be properly supported, such as a driver overlooking a dangerous vehicle.

  An object of the present invention is to provide a road-to-vehicle communication device, a road-to-vehicle communication system, and a road-to-vehicle communication method that can more reliably prevent vehicle position information from being lost.

  A road-to-vehicle communication device according to the present invention is a road-to-vehicle communication device that notifies a vehicle-mounted device of a position of an object moving on a road, and is based on a data receiving unit that acquires an actual measurement position of the object, and a predetermined movement pattern A position prediction unit that acquires a predicted position of the object, a prediction error determination unit that determines whether or not an error of the predicted position with respect to the measured position is within a predetermined range, and the error is within the predetermined range. If not, information indicating the measured position is transmitted to the in-vehicle device, and when the error is within the predetermined range, information indicating that the error is within the predetermined range instead of the measured position Is transmitted to the in-vehicle device.

  The road-to-vehicle communication system according to the present invention is a road-to-vehicle communication system that notifies a vehicle-mounted device of the position of an object moving on a road from the road-to-vehicle communication device, wherein the road-to-vehicle communication device acquires an actual measurement position of the object. A data receiving unit, a position prediction unit that acquires a predicted position of the object based on a predetermined movement pattern, and a prediction error determination that determines whether an error of the predicted position with respect to the measured position is within a predetermined range And when the error is not within the predetermined range, the measured position is transmitted to the in-vehicle device, and when the error is within the predetermined range, the error is replaced with the predetermined position. A data transmission unit that transmits information indicating that the information is within the range of the vehicle-mounted device, wherein the vehicle-mounted device receives the information from the road-to-vehicle communication device, and the information Said When indicating the measured position, the measured position is acquired as the position of the object, and when the information indicates that the error is within the predetermined range, the predicted position of the object based on the predetermined movement pattern is A position management unit that acquires the position of the object.

  The road-to-vehicle communication method of the present invention is a road-to-vehicle communication method for notifying an in-vehicle device of the position of an object moving on a road, the step of acquiring an actual position of the object, and the object based on a predetermined movement pattern Obtaining a predicted position, determining whether an error of the predicted position with respect to the measured position is within a predetermined range, and when the error is not within the predetermined range, When the error is within the predetermined range, the information indicating that the error is within the predetermined range is transmitted to the on-vehicle device instead of the actually measured position. A step of performing.

  According to the present invention, since transmission of the measured position can be replaced with transmission of information with a small data size, it is possible to more reliably prevent the loss of position information even when there is a lot of position information to be transmitted.

The system block diagram which shows the structure of the road-vehicle communication system which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the road-vehicle communication apparatus which concerns on this Embodiment 1, and a vehicle-mounted apparatus. The figure which shows the structure of the original vehicle position information in this Embodiment 1. The figure for demonstrating an example of the definition of the various parameters in this Embodiment 1. The figure which shows an example of the movement pattern list | wrist in this Embodiment 1. The figure which shows an example of the roadside position management database in this Embodiment 1. The figure which shows an example of the prediction error allowable range list | wrist in this Embodiment 1. The figure which shows an example of the vehicle side position management database in this Embodiment 1. The flowchart which shows an example of the whole operation | movement of the road-vehicle communication apparatus which concerns on this Embodiment 1. The figure which shows an example of the original vehicle position information in this Embodiment 1. First diagram showing a configuration of a DSSS packet in the first embodiment FIG. 2 is a second diagram showing the structure of a DSSS packet in the first embodiment The figure for demonstrating the data size of the vehicle position information in this Embodiment 1. The figure which shows an example of the vehicle position information in this Embodiment 1. The flowchart which shows an example of the whole operation | movement of the vehicle-mounted apparatus which concerns on this Embodiment 1. The block diagram which shows the structure of the road-vehicle communication apparatus which concerns on Embodiment 2 of this invention, and a vehicle-mounted apparatus. The figure which shows an example of the movement pattern list | wrist in this Embodiment 2. The figure which shows an example of the supplementary information management database in this Embodiment 2. The flowchart which shows an example of the whole operation | movement of the road-vehicle communication apparatus which concerns on this Embodiment 2. The flowchart which shows an example of the whole operation | movement of the vehicle-mounted apparatus which concerns on this Embodiment 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a system configuration diagram showing a configuration of a road-vehicle communication system according to an embodiment of the present invention. The present embodiment is an example in which the present invention is applied to the above-described DSSS.

  In FIG. 1, a road-vehicle communication system 100 includes a vehicle sensor 200, a road-vehicle communication device 300, and an in-vehicle device 400.

  The vehicle sensor 200 is a sensor provided above the road 500 near the intersection, and detects the vehicle identifier, position, speed, and traveling direction of the vehicle 600 located in the detection area 510 of the road 500. And the vehicle detector 200 transmits a detection result to the road-to-vehicle communication apparatus 300 regularly as vehicle position information by wireless communication or wired communication.

  The road-to-vehicle communication device 300 is a communication device provided on the side of the road 500, and transmits the vehicle position information received from the vehicle detector 200 to the in-vehicle device 400 by the above-described DSRC or the like. The road-to-vehicle communication device 300 transmits the vehicle position information to a vehicle-mounted device (not shown) of the vehicle 600, but the description thereof is omitted. More specifically, the road-to-vehicle communication device 300 determines, for each detected vehicle 600, whether or not the prediction error of the predicted position based on the predetermined movement pattern with respect to the actually measured position is within a predetermined range. Here, the detected vehicle refers to a vehicle located in the detection area 510. The prediction error is a difference between a predicted position of the detected vehicle 600 based on a predetermined movement pattern and an actual measurement position of the detected vehicle 600. When the prediction error is not within the predetermined range, the road-to-vehicle communication device 300 transmits information indicating the actual measurement position. When the prediction error is within the predetermined range, the road-to-vehicle communication device 300 replaces the actual measurement position with the prediction error. Transmits information indicating that is within a predetermined range.

  The in-vehicle device 400 is a communication device provided in a vehicle traveling on the road 500, and acquires the position of the detected vehicle 600 based on the vehicle position information received from the road-to-vehicle communication device 300. More specifically, when the received vehicle position information indicates a measured position, the in-vehicle device 400 acquires the measured position as the position of the detected vehicle 600. Further, when the received vehicle position information indicates that the above-described prediction error is within a predetermined range, the in-vehicle device 400 uses the detected position of the detected vehicle 600 based on the above-described predetermined movement pattern as the detected vehicle. Get as 600 position. The position of the detected vehicle 600 acquired by the in-vehicle device 400 is notified to the driver, for example.

  In such a road-to-vehicle communication system 100, when the prediction error of the predicted position of the vehicle based on a predetermined movement pattern with respect to the actual measurement position is within a predetermined range, the vehicle-mounted device 400 performs position prediction based on the movement pattern. I do. Thereby, the vehicle-mounted apparatus 400 can acquire the position of the detected vehicle 600 within a predetermined error range. Therefore, the road-to-vehicle communication system 100 may replace the transmission of the measured position with the transmission that the prediction error in the predetermined movement pattern is within the predetermined range (hereinafter referred to as “movement pattern notification”) in the road-to-vehicle communication. it can.

  The movement pattern notification can be realized by notifying only the presence / absence of application when there is one assumed movement pattern. In addition, when there are a plurality of assumed movement patterns, the movement pattern notification can be realized by notifying only which movement pattern it is. That is, the road-to-vehicle communication system 100 can replace the transmission of the measured position of the detected vehicle 600 in the road-to-vehicle communication with the transmission of information with a small data size. Therefore, the road-to-vehicle communication system 100 can reduce the road-to-vehicle communication data size without losing the vehicle position information. Therefore, when there is a lot of vehicle position information to be transmitted, that is, in the detection area 510, Even when the detection vehicle 600 exists, the necessary vehicle position information can be transmitted more reliably.

  Next, the configuration of the road-to-vehicle communication device 300 and the in-vehicle device 400 will be described.

  FIG. 2 is a block diagram showing the configuration of the road-to-vehicle communication device 300 and the in-vehicle device 400.

  In FIG. 2, the road-to-vehicle communication device 300 includes a roadside data receiving unit 310, a roadside movement pattern storage unit 320, a vehicle position prediction unit 330, a prediction error determination unit 340, a transmission data creation unit 350, and a roadside data transmission unit 360. .

  The roadside data reception unit 310 receives vehicle position information from the vehicle detector 200 and outputs the received vehicle position information to the vehicle position prediction unit 330 and the prediction error determination unit 340.

  The roadside movement pattern storage unit 320 stores in advance a movement pattern table describing a predetermined movement pattern of the vehicle to be detected. A movement pattern prescribes | regulates the relationship of the position in two different time of the vehicle which drive | works a road. In the present embodiment, it is assumed that the movement pattern table describes two movement patterns. Details of the movement pattern table will be described later.

  The vehicle position prediction unit 330 predicts the position, speed, and traveling direction of the detected vehicle based on the movement pattern table. Then, the vehicle position prediction unit 330 includes an actually measured position, speed, and traveling direction (hereinafter, collectively referred to as “measured position” as appropriate), and a predicted position, speed, and traveling direction (hereinafter, appropriately referred to as “predicted position”). ”Is output to the prediction error determination unit 340. The vehicle position prediction unit 330 holds a roadside position management database (database: DB) in which measured positions and predicted positions of the detected vehicle are accumulated. The vehicle position prediction unit 330 adds the measured position included in the vehicle position information to the roadside position management database. In addition, the vehicle position prediction unit 330 calculates a predicted position of the detected vehicle in each detection cycle from the road side position management database based on each movement pattern, and adds the calculated predicted position to the road side position management database. Details of the roadside location management database will be described later.

  The prediction error determination unit 340 determines, for each movement pattern, for each detection cycle, whether the prediction error of the predicted position of the detected vehicle with respect to the actual measurement position is within a predetermined range. When the prediction error determination unit 340 determines that any prediction error is not within the predetermined range, the prediction error determination unit 340 outputs the actual measurement position to the transmission data generation unit 350. When the prediction error determination unit 340 determines that the prediction error is within a predetermined range, the prediction error determination unit 340 outputs movement pattern information indicating the corresponding movement pattern to the transmission data creation unit 350. More specifically, the prediction error determination unit 340 stores in advance a prediction error allowable range list in which a predetermined range is described as a prediction error allowable range, and the prediction error is determined based on the prediction error allowable range list. It is determined whether it is within the range. Details of the prediction error allowable range list will be described later.

  The transmission data creation unit 350 creates vehicle position information based on the determination result of the prediction error determination unit 340 and outputs the created vehicle position information to the roadside data transmission unit 360. More specifically, when the actual measurement position is input, transmission data creation unit 350 outputs vehicle position information storing the actual measurement position to roadside data transmission unit 360. The vehicle position information storing the actual measurement position is the same information as the vehicle position information transmitted from the vehicle detector 200, and is hereinafter referred to as “uncompressed vehicle position information” as appropriate. In addition, when the movement pattern information is input, the transmission data creation unit 350 stores vehicle position information (hereinafter referred to as “compressed vehicle position information” as appropriate) in which the movement pattern information is stored instead of the actual measurement position. It outputs to the roadside data transmission part 360.

  The roadside data transmission unit 360 stores the input compressed vehicle position information and uncompressed vehicle position information in the actual data area of the DSSS packet, and transmits them to the in-vehicle device 400 using wireless communication.

  The road-vehicle communication device 300 is a computer including a storage medium such as a central processing unit (CPU) and a random access memory (RAM), and operates when the CPU executes a control program to be stored.

  When the prediction error is not within the predetermined range, the road-to-vehicle communication device 300 transmits information indicating the actually measured position to the in-vehicle device 400. When the prediction error is within the predetermined range, the road-to-vehicle communication device 300 replaces the actual position with the movement pattern. Information can be transmitted to the in-vehicle device 400. That is, the road-to-vehicle communication device 300 can appropriately transmit the compressed vehicle position information instead of the non-compressed vehicle position information.

  In FIG. 2, the in-vehicle device 400 includes a vehicle side data reception unit 410, a vehicle side movement pattern storage unit 420, a vehicle position management unit 430, and an information presentation unit 440.

  The vehicle-side data receiving unit 410 receives the DSSS packet from the road-to-vehicle communication device 300, and stores the compressed vehicle position information and the uncompressed vehicle position information stored in the actual data area of the received DSSS packet. The data is output to the position management unit 430.

  The vehicle-side movement pattern storage unit 420 stores in advance a movement pattern table having the same contents as the movement pattern table stored in the road-side movement pattern storage unit 320 of the road-vehicle communication device 300.

  When the input vehicle position information includes an actual position, the vehicle position management unit 430 collectively refers to the actual position, the current position, the speed, and the traveling direction of the detected vehicle (hereinafter, “current position”). ) Get as. Further, when the input vehicle position information includes movement pattern information instead of the actual measurement position, the vehicle position management unit 430 includes the movement pattern information and a movement pattern table stored in the vehicle-side movement pattern storage unit 420. Based on the above, a predicted position is calculated. Then, the vehicle position management unit 430 acquires the calculation result as the current position of the detected vehicle.

  More specifically, the vehicle position management unit 430 holds a vehicle side position management database in which the acquired current position of the detected vehicle is accumulated. When the vehicle position information in the compressed format is input, the vehicle position management unit 430 calculates the predicted position of the detected vehicle from the vehicle position management database based on the movement pattern specified by the vehicle position information. Details of the vehicle side position management database will be described later.

  The information presentation unit 440 refers to the vehicle-side position management database held by the vehicle position management unit 430, and uses information about the current positions of all detected vehicles using a display device (not shown) such as a liquid crystal display. To inform the driver.

  The in-vehicle device 400 is a computer including a CPU and a storage medium such as a RAM, and operates when the CPU executes a stored control program.

  When such an in-vehicle device 400 receives the measured position, the on-vehicle device 400 can acquire the measured position as the current position of the detected vehicle 600. Further, when the in-vehicle device 400 receives the movement pattern information, the in-vehicle device 400 can acquire the predicted position of the detected vehicle based on the movement pattern as the current position of the detected vehicle. Moreover, the in-vehicle device 400 can acquire the current position of the vehicle to be detected within a predetermined error range.

  Next, various information and various parameters used in the road-to-vehicle communication device 300 and the in-vehicle device 400 will be described.

  FIG. 3 is a diagram showing a configuration of vehicle position information (hereinafter referred to as “original vehicle position information” as appropriate) transmitted from the vehicle detector 200.

  As shown in FIG. 3, the original vehicle position information 710 is composed of four data items 711 including a vehicle identifier, a position, a speed, and a traveling direction. The data size 712 of each data item 711 is, for example, 4 bytes, 8 bytes, 2 bytes, and 2 bytes in order. In this case, the communication data size of the original vehicle position information 710 is 16 bytes.

  The vehicle identifier is identification information of the vehicle to be detected, and is a numerical value assigned by the vehicle detector 200, for example. The position, the speed, and the traveling direction are, for example, a position, a speed, and a traveling direction that are expressed using a coordinate system that is set based on the position of the intersection corresponding to the vehicle sensor 200.

  FIG. 4 is a diagram for explaining an example of the definition of the position, speed, and traveling direction of the vehicle position information.

  As shown in FIG. 4, the road-to-vehicle communication system 100 sets, for example, a common XY coordinate system 720 based on the center position and orientation of each intersection to the vehicle detector 200 and all the in-vehicle devices 400. Yes. Units for position, speed, and direction of travel are, for example, meters (m), meters per second (m / s), and degrees. For example, the position, speed, and traveling direction of the detected vehicle with the vehicle identifier “1” are coordinate values “(−10, 1)” in the XY coordinate system 720, speed “10 m / s”, and the north direction. A clockwise angle “90 degrees” with respect to the corresponding Y-axis direction is expressed. The position, speed, and traveling direction of the detected vehicle with the vehicle identifier “2” are coordinate values “(−1, 4)”, speed “0 m / s” in the XY coordinate system 720, and no traveling direction. It is expressed as. When the speed is “0 m / s”, the data item in the traveling direction has no meaning.

  FIG. 5 is a diagram illustrating an example of the movement pattern list.

  As illustrated in FIG. 5, the movement pattern list 730 describes the movement pattern 732 in association with the movement pattern number 731. In the present embodiment, it is assumed that the movement pattern list 730 describes two types of movement patterns 732 of “constant linear motion” and “constant deceleration motion until stopping at a stop line”. Hereinafter, the movement pattern of “constant linear motion” is referred to as “movement pattern 1”, and the movement pattern of “equal deceleration motion until stopping at the stop line” is referred to as “movement pattern 2”.

The movement pattern includes the position x _n−1 , y _n−1 , the speed v _n−1 , the traveling direction θ _n−1, and the current detection cycle of the detection cycle n−1 immediately preceding the vehicle traveling on the road. It is a relational expression showing the relationship between the position x _n and y _{n of n} , the velocity v _n , and the traveling direction θ _n .

“Movement pattern 1” is expressed by the following equation (1), for example.

“Movement pattern 2” is expressed by the following equation (2), for example.

  FIG. 6 is a diagram illustrating an example of a roadside position management database.

  As shown in FIG. 6, in the roadside position management database 740, the measured value 744 of each data item 743 and the movement are associated with the vehicle identifier 741 for each detected vehicle and for each period 742 corresponding to the detection period. A predicted value 745 for each pattern is recorded. The predicted value 745 for each movement pattern is based on the predicted value 745 when the predicted value 745 transmitted to the in-vehicle device 400 is present in the previous cycle n, and the previous cycle n when not present. It is calculated based on the actual measurement value.

  For example, the value corresponding to “movement pattern 1” in the predicted value 745 with the period n = 2 is a value when “movement pattern 1” is applied to the actual measurement value 744 with the period n = 1. The value corresponding to “movement pattern 2” in the predicted value 745 of the period n = 2 is a value when “movement pattern 2” is applied to the actual measurement value 744 of the period n = 1. Among the predicted values 745 with the period n = 3, the values corresponding to the “movement pattern 1” are the actually measured values 744 with the period n = 2, the predicted values 745 with the “movement pattern 1”, or the predicted values 745 with the “movement pattern 2”. This is a value when “movement pattern 1” is applied to any of the above. Among the predicted values 745 with the period n = 3, the values corresponding to the “movement pattern 2” are the measured values 744 with the period n = 2, the predicted values 745 with the “movement pattern 1”, or the predicted values 745 with the “movement pattern 2”. It is a value when “movement pattern 2” is applied to any of the above. Which value of the cycle n = 2 is used will be described later, but depends on the vehicle position information transmitted to the in-vehicle device 400 in the cycle n = 2.

  FIG. 7 is a diagram illustrating an example of a prediction error allowable range list.

  As shown in FIG. 7, the prediction error allowable range list 750 describes the prediction error allowable range 753 for each data item in association with the state 752 of the detected vehicle for each status item 751 indicating the status of the detected vehicle. is doing. The prediction error allowable range list 750 describes a smaller allowable range when the degree of risk of the detected vehicle is high. For example, when the detected vehicle has a high degree of risk, the detected vehicle is close to the center of the intersection, the detected vehicle is fast, or the signal of the lane in which the detected vehicle travels is blue. This is the case.

  For example, in the vehicle state 752 where the vehicle speed is 10 m / s or more, a position error of less than ± 0.3 m, a speed error of less than ± 0.2 m / s, and an error in the traveling direction of less than ± 5 degrees are This is described as a prediction error allowable range 753. For vehicle position information of a detected vehicle traveling at 10 m / s or more, a position error of less than ± 0.3 m, a speed error of less than ± 0.2 m / s, and less than ± 5 degrees If there is only an error in the traveling direction, it indicates that it can be used as effective information. The position error is the distance between the predicted value coordinates and the actually measured value coordinates.

  FIG. 8 is a diagram illustrating an example of the vehicle side position management database.

  As shown in FIG. 8, the value 764 of each data item 763 is recorded in the vehicle position management database 760 for each detected vehicle in association with the vehicle identifier 761 and for each cycle 762 corresponding to the detection cycle. The A value 764 corresponding to the “position” of the data item 763 is the actual measurement position in the period n when the actual measurement position is received. The value 764 corresponding to the “position” of the data item 763 is the predicted position when the corresponding movement pattern is applied to the value 764 of the previous period n−1 in the period n when the movement pattern information is received. It has become. That is, the value 764 of the vehicle side position management database 760 is the same as the actual measurement value 744 of the period n in the road side position management database 740 in the period n when the actual position is notified. Further, the value 764 of the vehicle side position management database 760 is the same as the predicted value 745 corresponding to the period n of the road side position management database 740 in the period n when the movement pattern is notified.

  Next, the operation of the road-to-vehicle communication device 300 and the operation of the in-vehicle device 400 will be described.

  FIG. 9 is a flowchart illustrating an example of the overall operation of the road-vehicle communication device 300. The road-to-vehicle communication device 300 repeatedly executes the process shown in FIG. 9 for each transmission cycle of the DSSS packet, for example.

  First, the roadside data receiving unit 310 receives data from the vehicle detector 200 (S1010), and when unprocessed vehicle position information is present in the received data (S1020: YES), the roadside data receiving unit 310 sets one of the vehicle position information. Acquire the actual measurement value included.

  FIG. 10 is a diagram illustrating an example of vehicle position information (original vehicle position information) received by the road-to-vehicle communication device 300.

As shown in FIG. 10 (A) ~ FIG 10 (C), the road-vehicle communication device 300, in each of the first to third periods, the vehicle position information 770 ₁ of the vehicle of the vehicle identifier "1", the vehicle It receives the vehicle position information 770 _{and second} vehicle identifier "2". The vehicle with the vehicle identifier “1” is a vehicle moving in the east direction on the west side of the intersection. The vehicle with the vehicle identifier “2” is a vehicle stopped near the center of the intersection. The total data size of the vehicle position information 770 ₁ and 770 ₂ of the vehicle with the vehicle identifier “1, 2” is 32 bytes.

  As described above, the vehicle position prediction unit 330 registers the received actual measurement value in the road position management database (see FIG. 6) as the actual measurement value of the current period n for each period n (S1030 in FIG. 9). Furthermore, the vehicle position prediction unit 330 registers the predicted value calculated based on each movement pattern (see FIG. 5) in the next cycle n + 1 of the roadside position management database (S1040). At this time, the actual value and the predicted value are registered for each vehicle based on the vehicle identifier.

  Then, when a predicted value is described in the current cycle n of the roadside position management database (S1050: YES), the vehicle position predicting unit 330 uses the measured value and the predicted value of each movement pattern as a prediction error determination. To the unit 340. As a result, the prediction error determination unit 340 calculates the difference (prediction error) between the actual measurement value and each prediction value (S1060), and based on the prediction error allowable range list (see FIG. 7) from the signal information and the like. A prediction error allowable range is determined (S1070).

  For example, attention is paid to the movement pattern 1 in the second period n = 2 record 746 (see FIG. 6) of the vehicle identifier “1”. In this case, the position prediction error (distance between the prediction value (-9, 1) and the actual measurement value (-9.1, 1)) is 0.1 m, and the speed prediction error (prediction value 10 m / The difference between s and the measured value 9.8 m / s) is 0.2 m / s, and the prediction error in the traveling direction (the difference between the predicted value 90 degrees and the measured value 90 degrees) is 0 degrees. .

  Further, attention is paid to the movement pattern 2 in the record 746 of the vehicle cycle “1” in the second cycle n = 2. In this case, the position prediction error (distance between the prediction value (−9.025, 1) and the actual measurement value (−9.1, 1)) is 0.075 m, and the speed prediction error (prediction value). The difference between 9.9 m / s and the measured value 9.8 m / s) is 0.1 m / s, and the prediction error in the traveling direction (difference between the predicted value 90 degrees and the measured value 90 degrees) is 0 degrees.

  When the prediction error determination unit 340 determines that the prediction error is within the determined prediction error allowable range (S1080: YES), the transmission data creation unit 350 specifies the vehicle position information specifying the corresponding movement pattern. Is generated. That is, the road-to-vehicle communication device 300 generates the compressed vehicle position information (S1090).

  For example, as shown in FIG. 6, in the vehicle identifier “1” in the second period n = 2, the vehicle speed is 5 m / s or more and less than 10 m / s, and the vehicle position (distance from the intersection center) is Since the measured value of the vehicle position is (−9.1, 1), it is less than 30 m. Therefore, from the prediction error allowable range list 750 shown in FIG. 7, the prediction error allowable range corresponding to the vehicle speed of 5 m / s or more and less than 10 m / s is “the position is less than ± 0.5 m and the speed is ± 0.5 m / s. less than s, travel direction is less than ± 10 degrees ”. Moreover, the prediction error allowable range corresponding to the vehicle position less than 30 m is “the position is less than ± 0.3 m, the speed is less than ± 0.2 m / s, and the traveling direction is less than ± 5 degrees”. That is, the prediction error allowable range corresponding to the vehicle position less than 30 m is stricter than the prediction error allowable range corresponding to the vehicle speed of 5 m / s or more and less than 10 m / s. Also, the prediction error tolerance range corresponding to the vehicle position less than 30 m is the prediction error tolerance range based on signal information “position is less than ± 0.5 m, speed is less than ± 0.5 m / s, and traveling direction is less than ± 10 degrees ”,“ Position is less than ± 1 m, speed is less than ± 1 m / s, and traveling direction is not determined ”. Therefore, the prediction error tolerance range is the most severe condition regardless of whether the signal is blue or red. “Position is less than ± 0.3 m, speed is less than ± 0.2 m / s, and traveling direction is less than ± 5 degrees. "

  The above-mentioned predicted values of the movement pattern 1 “position prediction error 0.1 m, speed prediction error 0.2 m / s, travel direction prediction error 0 degree” do not fall within this prediction error allowable range. The predicted values of the pattern 2 “position prediction error 0.075 m, speed prediction error 0.1 m / s, travel direction prediction error 0 degree” are within this prediction error allowable range. Accordingly, vehicle position information specifying the movement pattern 2 is generated. In addition, when there are a plurality of movement patterns in which the prediction error falls within the allowable range, the prediction error determination unit 340 desirably specifies the movement pattern with the smallest prediction error. Here, the smallest prediction error may be that the prediction error in a specific data item (for example, position) is the smallest, or the sum of values obtained by weighting the prediction errors of a plurality of data items. Or the average may be the smallest.

  At this time, the prediction error determination unit 340 feeds back the movement pattern information specified in the vehicle position information to the vehicle position prediction unit 330. The vehicle position prediction unit 330 stores the fed back movement pattern information as information for designating a movement pattern used for the next predicted value calculation.

  For example, for the vehicle identifier “1” shown in FIG. 6, the predicted value of the third period n = 3 uses the predicted value of the movement pattern 2 described above among the predicted values of the second period n = 2. Will be calculated.

  On the other hand, when the predicted value is not described in the current cycle of the roadside position management database (S1050: NO), the vehicle position prediction unit 330 and the prediction error determination unit 340 send only the actual measurement value to the transmission data creation unit 350. Forward. For example, this is the case when the first cycle n = 1 in FIG. 6 is the current cycle. As a result, the road-to-vehicle communication device 300 generates vehicle position information in which the actual measurement values are stored in the transmission data creation unit 350. That is, the road-to-vehicle communication device 300 generates uncompressed vehicle position information (S1100).

  When the prediction error determination unit 340 determines that the prediction errors based on all the movement patterns are not within the determined prediction error allowable range (S1080: NO), the transmission data creation unit 350 displays the actual measurement values. Is generated. That is, the road-to-vehicle communication device 300 generates uncompressed vehicle position information (S1100).

  Then, the road-to-vehicle communication device 300 repeats the processes of steps S1020 to S1100. When the road-to-vehicle communication device 300 completes the processing for all the vehicle position information included in the reception data from the vehicle detector 200 (S1020: NO), the road-side data transmission unit 360 transmits data. That is, the road-to-vehicle communication device 300 transmits the generated data of one or more vehicle position information (DSSS packet storing one or more vehicle position information) to the in-vehicle device 400 by broadcast communication ( S1110).

  11 and 12 are diagrams showing the structure of the DSSS packet.

  As shown in FIG. 11, the DSSS packet 780 includes an information storage number 781, an information identifier 782, and actual data 783. The information storage number 781 indicates the number of actual data stored in the DSSS packet 780. The information identifier 782 indicates the attribute 784 of the subsequent actual data 783. For example, the information identifier 782 of “5” indicates that the information type of the subsequent actual data 783 is sensor detection information, and stores vehicle position information (vehicle position information) detected by the sensor.

When the actual data 783 includes the vehicle position information, for example, as shown in FIG. 12, the detected number 785 and the vehicle position information 786 _{1 to} 786 _M of the _{first to} Mth (M is the number of detections in the cycle) are detected. Including. The detected number 785 is the number (that is, M) of the subsequent vehicle position information 786. The vehicle position information 786 _{1 to} 786 _M is vehicle position information in a compressed format or an uncompressed format created by the transmission data creation unit 350.

  The data size of the information storage number 781, the information identifier 782, and the detected number 785 is, for example, 1 byte. The data size of the individual vehicle position information 786 differs depending on whether it is a compressed format or an uncompressed format.

  As described above, the road-to-vehicle communication device 300 transmits uncompressed vehicle position information when the predicted position cannot be calculated or when the prediction error is not within the predetermined range. Further, the road-to-vehicle communication device 300 can transmit the compressed vehicle position information when the prediction error is within a predetermined range.

  The road-to-vehicle communication device 300 may perform the processes of steps S1030 to S1040 and the processes of steps S1050 to 1100 in FIG. 9 in the reverse order or in parallel.

  In addition, the road-to-vehicle communication device 300 periodically transmits uncompressed vehicle position information for each detected vehicle regardless of whether or not the actual measurement value can be replaced with the movement pattern information. And The reason for this will be described later. However, the road-to-vehicle communication device 300 uses the timing detected first for each detected vehicle as a reference so that the vehicle position information of all detected vehicles is not in an uncompressed format within one cycle n. It is desirable to shift the timing of the periodic transmission by, for example, starting transmission of the vehicle position information in a regular uncompressed format.

  Here, it will be described that the road-to-vehicle communication data size is reduced by transmitting the compressed vehicle position information.

  FIG. 13 is a diagram for explaining the data size of the vehicle position information.

  As shown in FIG. 13, the data size 792 of each data item 791 of the vehicle position information is 4 bytes for the vehicle identifier, 1 byte for the movement pattern, 8 bytes for the position, 2 bytes for the speed, and 2 bytes for the traveling direction. Become. Here, the road-to-vehicle communication device 300 sets the vehicle identifier and the movement pattern as the essential items 793 of the vehicle position information, and sets the position, speed, and traveling direction as the option items 793 of the vehicle position information. Here, the road-to-vehicle communication system 100 defines a movement pattern of “0” as information indicating that there is no movement pattern information, that is, the option item 793 describing the actual measurement value is stored. .

  In the case of the compressed vehicle position information, the road-to-vehicle communication device 300 generates vehicle position information including only the information of the essential item 793. In the case of non-compressed vehicle position information, the road-to-vehicle communication device 300 generates vehicle position information including information obtained by adding the optional item 794 to the essential item 793. Therefore, the data size of the vehicle position information (road-vehicle communication data size) is 17 bytes in the non-compressed format, but 5 bytes in the compressed format.

  FIG. 14 is a diagram illustrating an example of vehicle position information transmitted from the road-to-vehicle communication device 300 to the in-vehicle device 400. Here, an example in which the road-vehicle communication apparatus 300 receives the vehicle position information shown in FIG.

  As shown in FIGS. 14A to 14C, the vehicle with the vehicle identifier “1” has the first cycle and the third cycle, and the vehicle with the vehicle identifier “2” has the first cycle. The vehicle position information is in an uncompressed format. Further, the vehicle position information in the compressed format is the second cycle for the vehicle with the vehicle identifier “1” and the second and third cycles for the vehicle with the vehicle identifier “2”.

The total data size of the vehicle position information 810 ₁ and 810 ₂ of the vehicles with the vehicle identifiers “1” and “2” is 34 bytes in the first period, 10 bytes in the second period, and 22 bytes in the third period. It has become. Therefore, it can be seen that in the second period and the third period, the total data size is significantly reduced compared to the original vehicle position information of 32 bytes.

  The uncompressed format is that when the detected vehicle enters the detection area (because the measured position of the previous cycle has not been obtained), the movement state of the detected vehicle is the prediction of any movement pattern. This is when it does not fall within the allowable error range. However, when there are a large number of detected vehicles, the timing of entering the detection area is different, and a vehicle traveling normally corresponds to one of the movement patterns. Therefore, the total data size (road-vehicle communication data size) of the vehicle position information is reduced as a whole.

  FIG. 15 is a flowchart illustrating an example of the overall operation of the in-vehicle device 400. For example, the in-vehicle device 400 repeatedly executes the process illustrated in FIG. 15 every time a DSSS packet is received (that is, every transmission cycle).

  First, the vehicle-side data receiving unit 410 receives vehicle position information data (DSSS packet storing vehicle position information) from the road-vehicle communication device 300 (S2010). The vehicle-side data receiving unit 410 selects one piece of vehicle position information when there is unprocessed vehicle position information in the received data (S2020: YES). When the movement pattern is “0”, that is, when the vehicle position information is in an uncompressed format (S2030: YES), the vehicle position management unit 430 stores the vehicle identifier in the vehicle side position management database (see FIG. 8). It is determined whether or not it exists (S2040). This determination may be made, for example, by searching a value described as a vehicle identifier in the vehicle position information in the vehicle side position management database.

  When the vehicle identifier does not exist in the vehicle side position management database (S2040: NO), the vehicle position management unit 430 newly registers the vehicle identifier in the vehicle side position management database. Then, the vehicle position management unit 430 registers the position, speed, and traveling direction included in the vehicle position information in association with the newly registered vehicle identifier in the current cycle n of the vehicle side position management database (S2050). ).

  On the other hand, when the vehicle identifier exists in the vehicle side position management database (S2040: YES), the vehicle position management unit 430 proceeds to step S2060. Then, the vehicle position management unit 430 registers the position, speed, and traveling direction included in the vehicle position information in the current cycle n of the vehicle side position management database in association with the vehicle identifier (S2060).

  Further, the vehicle position management unit 430, when the movement pattern is other than “0” (“1” or “2” in the present embodiment), that is, the vehicle position information is in a compressed format (S2030: NO), The process proceeds to step S2070. Then, the vehicle position management unit 430 determines whether or not the vehicle identifier exists in the vehicle side position management database (S2070).

  When the vehicle identifier exists in the vehicle side position management database (S2070: YES), the vehicle position management unit 430 proceeds to step S2080. The vehicle position management unit 430 then determines the position and speed of the current cycle n from the position, speed, and traveling direction values of the previous cycle n−1 and the movement pattern described in the received vehicle position information. The traveling direction is calculated (S2080). Then, the vehicle position management unit 430 registers the calculation result in association with the vehicle identifier in the current cycle n of the vehicle side position management database (S2090).

  If the vehicle identifier does not exist in the vehicle-side position management database (S2070: NO) even though the compressed vehicle position information has been received (S2030: NO), the in-vehicle device 400 has the vehicle position information. No particular processing is performed for. This is because the position of the previous cycle for the corresponding detected vehicle is not acquired, and the predicted position cannot be calculated.

  In such a case, for example, when the vehicle position information received for the first time with respect to the detected vehicle with the in-vehicle device 400 is in the compressed format (before the first reception, the uncompressed vehicle position information of the detected vehicle) May have occurred). Even if the vehicle position information in the compressed format is continuously received as it is, the in-vehicle device 400 cannot acquire the position of the corresponding detected vehicle indefinitely.

  For this reason, as described above, the road-to-vehicle communication device 300 broadcasts uncompressed vehicle position information for each detected vehicle at regular intervals (for example, at intervals of 1 second). Thereby, the road-to-vehicle communication device 300 can prevent a situation in which the in-vehicle device 400 cannot acquire the position of the detected vehicle indefinitely due to the reduction in the road-to-vehicle communication data size.

  And the vehicle equipment 400 repeats the process of step S2020-S2090. When the vehicle-mounted device 400 completes the processing for all the vehicle position information included in the received data from the road-vehicle communication device 300 (S2020: NO), the information presentation unit 440 notifies the vehicle position information. That is, the in-vehicle device 400 notifies the driver or the like of the position, speed, and traveling direction of each detected vehicle in the current period n via, for example, a display screen (S2100).

  By such an operation, the vehicle-mounted device 400 acquires the position, speed, and traveling direction of the detected vehicle within a predetermined error range even when receiving the compressed vehicle position information, You can be notified.

  As described above, the road-to-vehicle communication system 100 according to the present embodiment can appropriately replace the transmission of the measured position of the detected vehicle in the road-to-vehicle communication with the movement pattern notification. Therefore, the road-to-vehicle communication system 100 according to the present embodiment can significantly reduce the road-to-vehicle communication data size, for example, more reliably prevent missing vehicle position information even when there are many detected vehicles. Can do.

(Embodiment 2)
In the first embodiment, the case where the above-described two movement patterns are applied has been described. However, the present invention can also be applied to various movement patterns such as “constant velocity circular motion”. However, depending on the movement pattern, a parameter depending on the structure of the intersection may be required when performing position prediction. For example, in the “constant velocity circular motion”, the predicted position cannot be calculated unless the turning radius is specified. Therefore, the road-to-vehicle communication device according to Embodiment 2 of the present invention can apply an applicable movement pattern by using information for each intersection (hereinafter referred to as “movement pattern supplementary information”) necessary for position prediction based on the movement pattern. Plan to expand.

  FIG. 16 is a block diagram showing the configuration of the road-vehicle communication device and the in-vehicle device according to the present embodiment, and corresponds to FIG. 1 of the first embodiment. The same parts as those in FIG.

  As shown in FIG. 16, the road-vehicle communication apparatus 300a according to the present embodiment newly includes a road-side movement pattern management unit 370a. Moreover, the road-vehicle communication apparatus 300a according to the present embodiment includes a transmission data creation unit 350a instead of the transmission data creation unit 350 of FIG. In the present embodiment, the roadside movement pattern storage unit 320 stores a movement pattern list describing more movement patterns than in the first embodiment.

  FIG. 17 is a diagram showing an example of the movement pattern list in the present embodiment.

  As shown in FIG. 17, the movement pattern list 730a in the present embodiment includes “constant linear motion”, “constant deceleration motion until stopping at the stop line”, “constant acceleration motion to the limit speed”, “constant circle”. It is assumed that movement patterns 732 of “movement (right turn)”, “constant speed circular movement (left turn)”, “equal deceleration movement to right turn standard speed”, and “equal deceleration movement to left turn standard speed” are described. Hereinafter, these movement patterns are referred to as “movement pattern 1” to “movement pattern 7” as appropriate.

“Movement pattern 4” to “Movement pattern 7” are represented by the following equations (3) to (6), for example. However, v _r , r _r , v _l , r _l are a right turn standard speed, a right turn turning radius, a left turn standard speed, and a left turn turning radius in this order.

The parameters v _r , r _r , v _l and r _l are information unique to each intersection. Therefore, these movement patterns 4 to 7 require these parameters v _r , r _r , v _l , r _l as movement pattern supplementary information.

  The roadside movement pattern management unit 370a stores in advance a supplementary information management database that describes supplementary movement pattern information of the intersection where the vehicle detector 200 is provided.

  FIG. 18 is a diagram illustrating an example of a supplementary information management database describing movement pattern supplementary information.

For example, in the supplementary information management database 820a, as the movement pattern supplementary information, a right turn standard speed (v _r ), a right turn radius (r _r ), a left turn standard speed (v _l ), and a left turn are provided for each intersection route 821. A value 822 for the radius of rotation (r _l ) is described. These values can be expressed by a data size of 2 bytes, for example.

  For example, a route 821 called “Route 1” is described as “Right turn turning radius: 7 m”. This indicates that the standard right turn turning radius of a vehicle that enters the intersection from the route 1 of the intersection where the vehicle detector 200 is installed and makes a right turn is 7 m. This parameter is determined from the structure of the intersection.

  In addition to the function described in the first embodiment, the transmission data creation unit 350a in FIG. 16 periodically transmits the movement pattern supplementary information described in the supplementary information management database 820a to the in-vehicle device 400. Have This transmission is performed, for example, by storing in the actual data area of the DSSS packet (see FIG. 11). The data of the movement pattern supplement information can be configured, for example, by connecting values in a predetermined order. In this case, for example, for an intersection with four routes, 33 bytes is obtained by adding 1 byte of the information identifier to 2 bytes × 16.

  In-vehicle device 400a according to the present embodiment has vehicle-side data reception unit 410a and vehicle position management unit 430a instead of vehicle-side data reception unit 410 and vehicle position management unit 430 in FIG. The vehicle-side movement pattern storage unit 420 stores a movement pattern table having the same contents as the movement pattern table stored in the road-side movement pattern storage unit 320 of the road-to-vehicle communication device 300.

  In addition to the functions described in the first embodiment, the vehicle-side data receiving unit 410a has a function of receiving movement pattern supplementary information from the road-vehicle communication device 300a. Specifically, for example, when the movement pattern supplement information is stored in the actual data part of the DSSS packet, the vehicle side data reception unit 410a acquires the movement pattern supplement information and outputs the movement pattern supplement information to the vehicle position management unit 430a. To do.

  In addition to the functions described in the first embodiment, the vehicle position management unit 430a holds the latest movement pattern supplementary information that is input, and uses this when, for example, the movement patterns 4 to 7 are applied.

  In the present embodiment, the communication band for road-to-vehicle communication is consumed 33 bytes more than in the first embodiment. However, in a situation where an increase in road-to-vehicle communication data size is a problem, that is, in a situation where there are many detected vehicles, the effect of reducing the data size described in the first embodiment is relatively large. Further, as the number of movement patterns prepared increases, the number of detected vehicles to which the compressed vehicle position information can be applied increases. Therefore, the road-to-vehicle communication system 100a according to the present embodiment as a whole can keep the road-to-vehicle communication data size low, and can more reliably prevent the loss of position information.

  Hereinafter, the operation of the road-to-vehicle communication device 300a and the operation of the in-vehicle device 400a will be described.

  FIG. 19 is a flowchart showing an example of the overall operation of the road-to-vehicle communication device 300a, and corresponds to FIG. 9 of the first embodiment. The same steps as those in FIG. 9 are denoted by the same step numbers, and description thereof will be omitted.

  The vehicle position prediction unit 330 uses necessary movement pattern supplementary information when registering the predicted value calculated based on the movement pattern in the next cycle n + 1 of the roadside position management database (S1041a). Further, the roadside data transmission unit 360 includes movement pattern supplementary information in the DSSS packet transmitted to the in-vehicle device 400 by broadcast communication, for example (S1111a).

  By such an operation, the road-to-vehicle communication device 300a can apply more variations of movement patterns, and can transmit movement pattern supplementary information necessary for the application to the in-vehicle device 400a.

  FIG. 20 is a flowchart showing an example of the overall operation of the in-vehicle device 400a, and corresponds to FIG. 15 of the first embodiment. The same steps as those in FIG. 15 are denoted by the same step numbers, and description thereof will be omitted.

  The vehicle-side data receiving unit 410 acquires movement pattern supplementary information from the received data (S2011a). The vehicle position management unit 430a holds this movement pattern supplement information. Further, the vehicle position management unit 430 uses the position, speed, and traveling direction values of the previous cycle n−1, the movement pattern described in the received vehicle position information, and necessary movement pattern supplementary information. Then, the position, speed, and traveling direction of the current period n are calculated (S2081a).

  By such an operation, the in-vehicle device 400a can receive the movement pattern supplementary information from the road-vehicle communication device 300a, and can acquire the position of the detected vehicle by the movement pattern notification for more variations of the movement pattern. .

  Thus, the road-to-vehicle communication system 100a according to the present embodiment transmits the movement pattern supplementary information from the road-to-vehicle communication device 300a to the in-vehicle device 400a, so that the applicable movement pattern can be expanded. Therefore, the road-vehicle communication system 100a according to the present embodiment can further reduce the road-vehicle communication data size.

  In the embodiment described above, the case where the present invention is applied to transmission of vehicle position information in DSSS has been described, but the application of the present invention is not limited to this. The present invention can be applied to various systems such as a system that detects the position of a pedestrian crossing a pedestrian crossing and notifies a nearby vehicle. However, the position information that can be the transmission target is the position information of the object that can be predicted based on the movement pattern.

  The road-to-vehicle communication device, the road-to-vehicle communication system, and the road-to-vehicle communication method according to the present invention are a road-to-vehicle communication device, a road-to-vehicle communication system, and a road-to-vehicle communication method that can more reliably prevent loss of position information. Useful. In particular, the present invention is suitable for an infrastructure cooperative safe driving support system for the purpose of reducing accidents.

100, 100a Road-to-vehicle communication system 200 Vehicle detector 300, 300a Road-to-vehicle communication device 310 Road-side data receiving unit 320 Road-side movement pattern storage unit 330 Vehicle position prediction unit 340 Prediction error determination unit 350, 350a Transmission data generation unit 360 Road-side data transmission Unit 370a roadside movement pattern management unit 400, 400a vehicle-mounted device 410, 410a vehicle side data reception unit 420 vehicle side movement pattern storage unit 430, 430a vehicle position management unit 440 information presentation unit

Claims (7)

A road-to-vehicle communication device that notifies a vehicle-mounted device of the position of an object moving on a road,
A data receiving unit for acquiring the measured position of the object;
A position prediction unit that acquires a predicted position of the object based on a predetermined movement pattern;
A prediction error determination unit that determines whether or not an error of the predicted position with respect to the measured position is within a predetermined range;
When the error is not within the predetermined range, information indicating the measured position is transmitted to the in-vehicle device. When the error is within the predetermined range, the error is replaced with the measured position. A data transmission unit that transmits information indicating that it is within the range of the vehicle-mounted device,
Road-to-vehicle communication device. The predetermined movement pattern defines a positional relationship between two different times of an object moving on the road,
The position prediction unit stores a past actual measurement position and a predicted position of the object, and uses the past predicted position when the predicted position of the object can be obtained using the past predicted position. If the predicted position of the object cannot be acquired using the past predicted position, the predicted position of the object is acquired using the past actually measured position.
The road-to-vehicle communication device according to claim 1. The data transmitter is
Transmitting information indicating a movement pattern in which the error falls within the predetermined range among the plurality of predicted positions based on a plurality of predetermined movement patterns to the in-vehicle device;
The road-to-vehicle communication device according to claim 2. The data transmitter is
Regardless of whether the error is within the predetermined range, information indicating the measured position is periodically transmitted to the in-vehicle device.
The road-vehicle communication apparatus of Claim 3. The data transmitter is
Additional information necessary for obtaining the predicted position of the object based on the predetermined movement pattern is further transmitted to the in-vehicle device.
The road-vehicle communication apparatus of Claim 3. A road-to-vehicle communication system that notifies a vehicle-mounted device of the position of an object moving on a road from a road-to-vehicle communication device,
The road-to-vehicle communication device is
A data receiving unit that acquires the actual position of the object, a position prediction unit that acquires the predicted position of the object based on a predetermined movement pattern, and whether an error of the predicted position with respect to the actual position is within a predetermined range A prediction error determination unit that determines whether or not the measured position is transmitted to the in-vehicle device when the error is not within the predetermined range, and is replaced with the measured position when the error is within the predetermined range. A data transmission unit that transmits information indicating that the error is within the predetermined range to the in-vehicle device,
The in-vehicle device is
A data receiving unit that receives the information from the road-to-vehicle communication device, and when the information indicates the measured position, the measured position is acquired as the position of the object, and the information is within the predetermined range. A position management unit that acquires the predicted position of the object based on the predetermined movement pattern as the position of the object.
Road-to-vehicle communication system. A road-to-vehicle communication method for notifying an in-vehicle device of a position of an object moving on a road,
Obtaining a measured position of the object;
Obtaining a predicted position of the object based on a predetermined movement pattern;
Determining whether an error of the predicted position with respect to the measured position is within a predetermined range;
When the error is not within the predetermined range, information indicating the measured position is transmitted to the in-vehicle device. When the error is within the predetermined range, the error is replaced with the measured position. Transmitting information indicating that it is within the range to the in-vehicle device,
Road-to-vehicle communication method.

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