JP4918807B2 - Vehicle position calculation device, vehicle selection method - Google Patents

Description

  The present invention relates to a vehicle position calculation device and a vehicle selection method for detecting the position of a preceding vehicle when following traveling, and in particular, to detect the position of a preceding vehicle using inter-vehicle communication means that communicates between adjacent vehicles. The present invention relates to a vehicle position calculation device and a vehicle selection method.

  Vehicle-to-vehicle communication has been proposed in which vehicle-mounted communication devices communicate directly with each other and use information from other vehicles including the preceding vehicle to improve the safety and efficiency of automobile traffic. If the position and traveling state of another vehicle can be detected by inter-vehicle communication, automatic driving, cooperative traveling, and the like are possible.

  If vehicle-to-vehicle communication is possible, the position information of the other vehicle can be acquired by a position detection device such as GPS (Global Positioning System) mounted on the other vehicle (see, for example, Patent Document 1). The own vehicle detects the position of the own vehicle by a position detection device mounted on the own vehicle, so if the position information is compared, it is possible to support driving such as sounding an alarm when abnormally approaching another vehicle Become.

In addition, a method has been proposed in which GPS satellites commonly received by the host vehicle and other vehicles are detected by inter-vehicle communication and the position of the other vehicle is calculated (see, for example, Patent Document 2). In the position calculation method described in Patent Document 2, the difference in radio wave arrival time from a common GPS satellite is canceled to cancel the radio wave arrival time error, and the relative position of another vehicle based on the host vehicle is calculated. I am trying.
JP 2005-84790 A JP-A-10-148665

  However, even if the position is calculated by the GPS satellite, each position calculation method is various, and each has a position error that changes uniquely and dynamically. For this reason, as described in Patent Document 1, it is difficult to obtain an accurate relative position of another vehicle even if the position of the other vehicle is received.

  In addition, the static method and the kinematic method are known as a method using the difference in arrival time of GPS satellites. However, since the static method requires a positioning time of at least 10 minutes to 1 hour, the positioning of the moving object is required. It is difficult to apply. In addition, since the kinematic method requires a base station whose position is known, it cannot be applied in a state where the base station is not detected. In addition, although the arrival time of radio waves to other vehicles can be acquired by inter-vehicle communication, errors cannot be canceled unless the specifications of the internal processing such as the relative position calculation method are the same as the own vehicle and other vehicles. It is difficult to calculate the relative position of the other vehicle.

  In view of the above-described problems, an object of the present invention is to provide a vehicle position calculation device and a vehicle selection method that can detect the position of another vehicle communicating between vehicles with high accuracy.

  In view of the above problems, the present invention provides other vehicle position detection means (for example, surrounding monitoring means 11) for detecting the position of another vehicle mounted on the own vehicle, and other vehicle position for acquiring position information of the other vehicle from the outside. Information acquisition means (for example, inter-vehicle communication means 14) and other vehicle selection means (for example, arithmetic processing means 10) for selecting another vehicle with position information corresponding to the position of the other vehicle detected by the other vehicle position detection means. And a vehicle position calculation device.

In order to solve the above problems, the present invention provides other vehicle position detection means for detecting the position of another vehicle mounted on the own vehicle, other vehicle position information acquisition means for acquiring position information of the other vehicle from the outside, Another vehicle selection means for selecting another vehicle of the position information corresponding to the position of the other vehicle detected by the other vehicle position detection means, and the other vehicle selection means is detected by the other vehicle position detection means. Forming a first vector indicating the amount of movement and direction of movement of the other vehicle and a second vector indicating the amount of movement and direction of movement based on the position information of the other vehicle acquired by the other vehicle position information acquisition means It has line segment formation means, and a coincidence degree is detected based on the degree of overlap of the 1st vector and the 2nd vector which the line segment formation means formed .

  It is possible to provide a vehicle position calculation device and a vehicle selection method capable of detecting the position of another vehicle communicating between vehicles with high accuracy.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a functional block diagram of the vehicle position calculation apparatus of the present embodiment. The vehicle position calculation device makes it possible to control the inter-vehicle distance with high accuracy when the vehicle travels following a preceding vehicle with an ACC (adaptive cruise control) device.

  The vehicle position calculation device is controlled by calculation processing means 10 to which peripheral monitoring means 11, information providing means 12, vehicle control means 13, vehicle-to-vehicle communication means 14, navigation means 15 and map database 17 are connected. The arithmetic processing means 10 is connected to in-vehicle devices such as a winker 18, a light 19, a hazard 20, and a brake 21. These are connected to each other by an information system LAN or a body system LAN such as a CAN (Controller Area Network).

  The surroundings monitoring means 11 monitors the surroundings of the vehicle such as the front and rear of the vehicle, and specifically detects a laser radar, a millimeter wave radar, a photographing device for photographing the front and rear of the vehicle, and a pedestrian at night. It is a night vision camera. Laser radars and millimeter wave radars acquire the shape and distance information of obstacles ahead by measuring the time from when a radar pulse is emitted until it is received. The radar apparatus applies a pulse current to the laser diode and starts measuring the timer counter. The laser diode supplied with the pulse current irradiates a laser pulse proportional to the current forward. The laser pulse reflected by the obstacle in front is received by the light receiving unit, and the measurement of the timer counter is stopped. Since the measured time is proportional to the distance to the obstacle, if this value is multiplied by an appropriate coefficient, distance information to the obstacle is also acquired.

  Since the radar device continuously emits laser pulses while changing the laser pulse emission direction so that the laser scans a predetermined range ahead of the traveling direction of the vehicle, by repeating the above-described operation, at each scanning point Distance information to the obstacle can be obtained. Since the obstacle is, for example, a preceding vehicle or a guardrail, the periphery monitoring unit 11 detects the distance and direction to the preceding vehicle.

  Further, when the periphery monitoring means 11 is a photographing apparatus, it has a photoelectric conversion element such as a CCD or CMOS, photoelectrically converts light incident from the front of the vehicle with a photodiode, reads the accumulated charge as a voltage, amplifies it, and outputs A / D conversion is performed to convert it into a digital image (hereinafter simply referred to as image data) having a predetermined luminance gradation (for example, 256 gradations).

  Even if there is only one photographing device, it is possible to obtain distance information from the subject by image processing. However, in the case of a stereo camera, the parallax between the two cameras can be obtained by analyzing the two image data photographed at the same time. Based on the obtained parallax, the focal length of the camera, the distance between the two cameras, and the like, distance information is obtained for each pixel from the principle of triangulation.

  The vehicle control means 13 performs adaptive cruise control by communicating with a brake ECU (Electrical Control Unit), an engine ECU and the like. The vehicle control unit 13 causes the vehicle to follow the vehicle at a speed set by the driver, and performs a tracking operation that maintains the inter-vehicle distance when a preceding vehicle is detected. The engine ECU controls the opening of a throttle valve disposed in the middle of the intake passage to the engine based on the speed supplied from the vehicle control means 13 so as to travel at the set speed when no preceding vehicle is detected. . When the preceding vehicle is detected, the throttle opening is controlled so as to maintain the inter-vehicle distance from the preceding vehicle, and when the preceding vehicle decelerates, the brake ECU applies braking to the wheels.

  The accelerator pedal and the throttle valve are connected so that the amount of depression of the accelerator pedal is linked to the throttle opening. The throttle valve opening according to the depression of the accelerator pedal and the control by the engine ECU can be operated independently, but the larger one of the two operations reflects the throttle valve control. . Further, the transmission controller selects a gear position of the automatic transmission necessary for controlling the speed of the host vehicle according to an instruction from the engine ECU.

The vehicle-to-vehicle communication means 14 includes a transmitter / receiver (hereinafter simply referred to as a transmitter / receiver) that can be used for vehicle-to-vehicle communication, and a radio frequency band (for example, a millimeter wave of 30 GHz to 300 GHz band) by a communication antenna. ) To achieve inter-vehicle communication with other vehicles. As the communication method, for example, a spread spectrum method can be adopted. The inter-vehicle communication includes communication between vehicles via infrastructure, that is, communication between vehicles in which part or all of each link is realized as road-to-vehicle communication.

  The navigation means 15 is connected to a GPS (Global Positioning System) receiver 16 and uses the arrival time of radio waves transmitted from GPS satellites to determine the position of the vehicle by a single positioning method or a DGPS (Differential GPS) method. Is estimated with high accuracy.

  The navigation means 15 is connected to a vehicle speed sensor for detecting the speed of the host vehicle and a gyro sensor for detecting the traveling direction. The position of the vehicle is increased by autonomous navigation based on the coordinate information of the host vehicle detected by the GPS. Estimate to accuracy. That is, based on the vehicle speed measured by the vehicle speed sensor and the traveling direction of the host vehicle measured by the gyro sensor, the current position of the vehicle is estimated by autonomous navigation while accumulating the traveling distance and traveling path according to the traveling direction.

  The navigation means 15 also uses the map database 17 to finally determine the current position by a map matching method for associating the road of the road map extracted from the map database 17 and the position of the vehicle with respect to position estimation by autonomous navigation. Is accurately estimated.

  The map database 17 is an HDD, CD, DVD-ROM or the like in which road map information such as road networks and intersections is stored in association with latitude and longitude. The map database 17 is a table composed of information related to nodes (points where roads and roads intersect, that is, intersections) and information related to links (roads connecting nodes and nodes) corresponding to an actual road network. Database.

  The node table has node numbers, coordinates, the number of links flowing out from the nodes, and their link numbers. The link table includes a link number, a start point node and an end point node constituting the link, a link length, a link direction, and the like. The node number and the link number are determined so as not to overlap each other. Therefore, a road network is formed by following the node number and the link number.

  The map database 17 stores road information such as the road width and the number of lanes. In addition, road type information such as highways, general national roads, and local roads, buildings such as department stores and overpasses, traffic rules such as speed limits, one-way traffic, U-turn prohibition, and the like are stored.

  When the destination is input, the navigation means 15 converts the link length, width, necessity of turning left and right, etc. into costs, calculates the route from the current location to the destination so as to reduce the cost, and provides it to the driver To do.

  The blinker 18, the light 19, the hazard 20, the brake 21, and the like send on / off and operation status signals of these devices to the arithmetic processing means 10.

  The information providing unit 12 performs control for vehicle-to-vehicle communication such as buffering of information to be transmitted by the vehicle-to-vehicle communication unit 14 and buffering of received information, conversion of a communication method, and data communication by a predetermined protocol.

Information to be transmitted / received includes vehicle position information by the navigation means 15, distance information from the preceding vehicle detected by the periphery monitoring means 11, image information by the in-vehicle camera, control signals by various control devices, detection signals by various sensors, various switches Various on-off signals (hereinafter referred to as own vehicle information). The information provided by the information providing means 12 is not limited to these, and the host vehicle information may include any information that can be useful for other vehicles or the host vehicle through inter-vehicle communication. The information providing means 12 updates the own vehicle information stored in the buffer at predetermined intervals.

  Further, with the same configuration, various signals (hereinafter referred to as other vehicle information) are received by the inter-vehicle communication unit 14 from other vehicles provided with the inter-vehicle communication unit 14.

  The information providing unit 12, the vehicle control unit 13, and the arithmetic processing unit 10 are microcomputers in which a CPU, a ROM, a RAM, an NV-RAM (Non-Volatile RAM), a communication unit, and the like are connected by a bus, and are stored in the ROM. The above-described control is executed by the CPU executing the program. The information providing unit 12 and the arithmetic processing unit 10 may be mounted on an integrated microcomputer.

  The arithmetic processing means 10 will be described in detail in the embodiment, but the arithmetic processing means 10 mainly matches the position of the preceding vehicle detected by the periphery monitoring means 11 with the position information of the other vehicle acquired by inter-vehicle communication. Other vehicle selection means for calculating the degree and selecting a preceding vehicle from other vehicles is provided. The other vehicle selection means forms the movement amount of the other vehicle as a line segment based on the position information of the preceding vehicle or the other vehicle, and calculates the coincidence based on the degree of superimposition of these line segments.

  Further, the arithmetic processing means 10 detects a time delay of the position information of the other vehicle received by the inter-vehicle communication, and transmits a correction value of the detected time delay to the other vehicle. Output control means for increasing or decreasing the output of the communication means 14 is provided. The CPU of the arithmetic processing unit 10 executes the control described in the embodiment by executing a program that realizes the other vehicle selection unit, the time delay correction unit, and the output control unit.

  In the present embodiment, selection of a preceding vehicle when following traveling by ACC will be described. FIG. 2 is a flowchart showing a flow of processing for determining a preceding vehicle. In the present embodiment, the other vehicle selection means selects another vehicle corresponding to the preceding vehicle detected by the periphery monitoring means 11 based on the position information acquired by the inter-vehicle communication means 14.

  First, the arithmetic processing means 10 acquires the relative distance from the preceding vehicle by the periphery monitoring means 11 (S11). Although the relative distance can be detected for each type of the peripheral monitoring means 11 (radar or camera), when a relative distance is detected from a plurality of peripheral monitoring means 11, the relative distance is detected in association with the positioning means. Here, the relative distance is detected by a radar. Since the relative distance is acquired continuously, the relative speed is obtained by time differentiation of the relative speed.

  Next, the other vehicle selection means forms (maps) the relative position of the preceding vehicle on a predetermined plane based on the detected relative distance (S12). The other vehicle selection means maps as one end of a line segment starting from the approximate center of the front bumper of the host vehicle and starting from the relative distance of the preceding vehicle. The end point of the line segment is determined by the next relative distance detected periodically. Note that the end of the line segment may be determined by the relative speed detected by the periphery monitoring unit 11. Since such a line segment indicates the amount and direction of movement of the preceding vehicle detected by the radar, this line segment is referred to as a radar vector.

  Next, the arithmetic processing means 10 acquires other vehicle information of surrounding vehicles by the inter-vehicle communication means 14 (S13). The other vehicle selection means extracts position information and speed from the received other vehicle information, and maps the position of the other vehicle (S14). The position information transmitted from the other vehicle is, for example, coordinate information by GPS, and the speed includes information indicating the traveling direction. Since the position of the host vehicle is clear by the navigation means 15, the relative position (relative distance) is known from the difference from the position information of the other vehicle.

  Similarly, the other vehicle selection means maps as one end of a line segment starting from the relative distance of the other vehicle. The end point of the line segment is determined by the next position information detected periodically. Since the line segment of the other vehicle detected based on the position information received by the inter-vehicle communication indicates the movement amount and the movement direction of the other vehicle detected by the GPS, this line segment is referred to as a GPS vector.

  In the inter-vehicle communication, the other vehicle information is received from all other communicable vehicles, so that all the received other vehicles are mapped.

  The other vehicle selection means repeats the same process at least twice to determine whether or not a line segment has been formed (S15). In other words, the end of the line segment is determined by repeating twice or more. If the line segment is formed regularly, the length of the line segment indicates the relative speed.

  In the present embodiment, not only the movement amount and direction but also an index of thickness is introduced into the GPS vector. The thickness of the GPS vector is determined according to the position detection accuracy of the position information.

  FIG. 3 shows an example of a regulation table that defines the thickness of the GPS vector. In FIG. 3, the thickness of the GPS vector is defined in association with the positioning means and the positioning situation (accuracy information in the claims). FIG. 3 shows that “◯” is used as a positioning means.

  The thickness of the GPS vector is defined in four stages as an example, and the larger the numerical value, the higher the position detection accuracy. For example, when the positioning means is a radar, the thickness is defined as “1”. In the case of radar, a predetermined accuracy can be expected regardless of the positioning situation such as fog or rain, so classification may be performed although it is not classified according to the positioning situation.

In the case of positioning by GPS, since the position detection accuracy differs depending on the number of captured GPS satellites and the presence or absence of map matching (indicated by MM in the figure), the thickness of the GPS vector is defined according to these positioning conditions.
(A1) When the position is detected only by GPS, the thickness of the GPS vector is “3”.
(A2) When the position is not detected at all, the thickness of the vector is “1”.
(A3) When the position is detected by GPS and autonomous navigation, the thickness of the GPS vector is “3”.
(A4) When the GPS satellite is not captured and the position is detected only by autonomous navigation, the thickness of the GPS vector is “2”.
(A5) When the position is detected by GPS, autonomous navigation, and map matching, the thickness of the GPS vector is “4”.
(A6) When the position is detected by map matching and autonomous navigation, the thickness of the GPS vector is “3”.
(A7) When the position is detected only by map matching, the thickness of the GPS vector is “1”. The arithmetic processing means 10 maps the radar vector and the GPS vector based on the thickness definition as shown in FIG.

  FIG. 4A shows an example of mapped line segments. In FIG. 4A, the line segment L24 is a radar vector. In the detection of the preceding vehicle by the radar, normally, only the immediately preceding preceding vehicle is detected, and therefore one radar vector L24 is mapped in FIG. The thickness is “1”. In FIG. 4A, GPS vectors G25 to G27 of three other vehicles are shown.

  When the predetermined number of mappings are completed, the arithmetic processing means 10 evaluates the degree of coincidence between the radar vector L24 and the GPS vectors G25 to G27 by inter-vehicle communication from the mapping result as shown in FIG. 4A (S16). . A method for determining the degree of coincidence will be described later, but the other vehicle selection means selects another vehicle that indicates a GPS vector having a large degree of coincidence with the radar vector L24.

  As shown in FIG. 4A, when the GPS vector superimposed on the radar vector L24 is not detected, the arithmetic processing means 10 determines that the preceding vehicle is not selected, and repeats the processing of FIG. 2 from step S11 (S17).

  By repeating, the arithmetic processing means 10 is obtained by the number of repetitions of the radar vector and GPS vector of the same other vehicle. FIG. 4B shows radar vectors and GPS vectors mapped twice.

  In FIG. 4B, the same reference numeral is assigned to the same line segment. However, the GPS vector of the same other vehicle may have a different thickness due to a change in the positioning situation.

  As shown in FIG. 4B, when a GPS vector that overlaps with a radar vector more than a predetermined value is detected, a preceding vehicle is selected and the process of FIG. 2 is terminated.

  Subsequently, the evaluation of coincidence will be described. The degree of coincidence is evaluated based on evaluation points calculated based on the difference in length between the radar vector and the GPS vector, the difference in angle, and the degree of overlap.

  FIG. 5 shows an example of a flowchart showing the matching degree evaluation procedure by the other vehicle selection means.

  First, the other vehicle selection means calculates an evaluation point based on the difference between the lengths of the radar vector and the GPS vector and an evaluation point based on the difference in angle (S21).

  FIG. 6A is a diagram illustrating an example of the relationship between the length difference and the evaluation point. In FIG. 6A, the evaluation score when the length difference is within ± 10% is “3”, and the evaluation score when the length difference is ± 10% to ± 20% is “2”. The evaluation score when the difference of ± 20% to ± 30% is “−1”, and the evaluation score when the length difference is ± 30% or more is “−2”.

  FIG. 6B is a diagram illustrating an example of the relationship between the angle difference and the evaluation points. In FIG. 6B, the evaluation score is “3” when the angle difference between the radar vector and the GPS vector is within ± 5 degrees, and the evaluation score is “2” when ± 5 to ± 10 degrees. The evaluation score in the case of degrees to ± 20 degrees is “1”, and the evaluation score in the case of ± 20 degrees or more is “−1”.

  FIG. 7 is a diagram illustrating an example of a relationship between a radar vector and a GPS vector. For example, the other vehicle selection means creates a square mesh, and sets the length of one side of the square as the longer one of the radar vector or GPS vector, and the size of the mesh as the thickness of the radar vector.

  The other vehicle selection means extracts the length and direction of the radar vector and the GPS vector, and refers to FIG. 6 (a) to evaluate the difference between the length and the angle difference with reference to FIG. 6 (b). The evaluation points are extracted.

  Next, the other vehicle selection means extracts an evaluation point based on the overlapping degree of the radar vector and the GPS vector (S22). FIG. 6C shows the relationship between the degree of overlap between the radar vector and the GPS vector and the evaluation point. In FIG. 6C, the evaluation point is determined according to the ratio of the length of the shorter vector to the longer length of the radar vector or GPS vector.

  For example, the evaluation score when the radar vector and the GPS vector overlap by 80% or more is “3”, the evaluation score when 40-80% overlap is “2”, the evaluation score when 20-40% overlap Is “1”, and the evaluation score when the overlap is less than 20% is “0”.

  The other vehicle selection means calculates the degree of overlap based on the ratio of overlapping meshes from the relationship between the radar vector and the GPS vector as shown in FIG. 7, and extracts evaluation points from FIG.

  When all evaluation points are extracted for one GPS vector, the other vehicle selecting means adds all the evaluation points and stores them in association with the GPS vectors (S23).

  The evaluation points may be weighted. The degree of coincidence can be evaluated by emphasizing an index (for example, an angle difference) that greatly affects the degree of coincidence by weighting.

  Since the other vehicle selecting means adds up the evaluation points of all the GPS vectors with respect to one radar vector, in this embodiment, three evaluation points are obtained by the addition.

  Next, the other vehicle selection means adds past evaluation points for each GPS vector (S24). Since the past evaluation points are stored when the preceding vehicle is not determined in step S17 in the flowchart of FIG. 2, no addition is made when processing step S24 for the first time. By adding past evaluation points, it becomes easier to determine the preceding vehicle.

  Next, the other vehicle selecting means determines whether or not there is a GPS vector having an evaluation point equal to or greater than a predetermined value (S25). If there is no GPS vector with an evaluation point equal to or greater than the predetermined value (No in S25), the determination in step S17 in the flowchart of FIG. 2 is also No, and the other vehicle selection means maps the next radar vector and GPS vector.

  If there is a GPS vector with an evaluation score equal to or greater than a predetermined value (Yes in S25), if there are a plurality of GPS vectors, another vehicle with a GPS vector with the maximum evaluation score is selected (S26). With the above processing, another vehicle having a high degree of coincidence with the preceding vehicle detected by the laser can be selected by inter-vehicle communication.

  The degree of coincidence may be evaluated using a method for evaluating the degree of approximation between vectors. For example, when a radar vector and a GPS vector are represented as shown in FIG. 7, the degree of coincidence can be evaluated by template matching using the radar vector as a standard template. In this case, the evaluation score is determined based on the degree of overlap when the correlation is maximized.

  Further, only the length and direction of the radar vector and the GPS vector may be used, and the inner product of the vectors may be used as an evaluation point for the coincidence between the radar vector and the GPS vector. Since the radar vectors are common, the magnitude of correlation based on the vector direction can be obtained by taking the inner product of the vectors.

  Although the thickness of the line segment is changed depending on the positioning method and the positioning situation, the thickness may be the same for all the line segments.

  As described above, according to the present embodiment, it is possible to select a preceding vehicle with high accuracy by inter-vehicle communication. If a preceding vehicle can be selected, more advanced control of the inter-vehicle distance can be achieved, for example, by reducing or increasing the inter-vehicle distance using inter-vehicle communication during follow-up traveling.

  The position information of other vehicles received by inter-vehicle communication is extracted from the received other vehicle information due to positioning delay by the preceding vehicle, processing delay, communication delay, internal processing delay of the own vehicle, etc. Sometimes the actual position of the other vehicle has already shifted. In this embodiment, the time delay caused by this communication is measured and corrected, and the correction value is transmitted to another vehicle (preceding vehicle) so that the vehicle position is converged so that the time delay is reduced during the follow-up traveling. The arithmetic device will be described.

  In this embodiment, the position prefetching process by the preceding vehicle is required, but the structure of the preceding vehicle is the same as that of the own vehicle, and the navigation means 15 of the preceding vehicle prefetches the position of the preceding vehicle.

  In the present embodiment, the preceding vehicle is selected according to the first embodiment, and the vehicle control means 13 is in a state in which a follow-up running is performed in which the distance between the preceding vehicle and the preceding vehicle is kept constant up to a predetermined cruise speed. .

  FIG. 8A is a flowchart showing a processing procedure for the arithmetic processing means 10 to converge so that the time delay is reduced during the follow-up running.

  First, the time delay correction means causes the vehicle control means 13 to increase the inter-vehicle distance beyond the set distance (S31). The amount of increase in distance and the time at the start and end of the increase are known to the time delay correction means.

  The arithmetic processing means 10 receives other vehicle information from the preceding vehicle by inter-vehicle communication while detecting the distance from the actual preceding vehicle by a radar sensor or the like (S32). The time until the distance obtained by the inter-vehicle communication becomes equal to the distance with the actual preceding vehicle is a time delay of the preceding vehicle.

  The time delay correction means transmits the detected time delay information to the preceding vehicle by inter-vehicle communication (S33).

FIG. 8B is a flowchart showing a procedure of processing in which the preceding vehicle corrects the time delay.
The preceding vehicle receives time delay information from the own vehicle through inter-vehicle communication (S41). Then, the preceding vehicle prefetches the position of the preceding vehicle by the received time delay (S42). That is, when the time delay is several seconds, the position where the preceding vehicle exists several seconds ahead is acquired. Since the preceding vehicle travels a few seconds ahead on the currently traveling road, the position where the preceding vehicle exists a few seconds ahead is easy due to the current traveling position, traveling speed, and time delay. You can get it.

  The preceding vehicle then sets the pre-read vehicle position to be transmitted to the host vehicle through inter-vehicle communication, and transmits the pre-read position information to the host vehicle (S43).

  It should be noted that an upper limit is set for the pre-reading time so that correction is not excessive, and more preferably, an upper limit is set according to the speed of the preceding vehicle.

  Returning to FIG. 8A, the time delay correcting means returns the inter-vehicle distance to the set distance (S34). Then, as in step S32, other vehicle information is received from the preceding vehicle by inter-vehicle communication while detecting the distance from the actual preceding vehicle by a radar sensor or the like. The other vehicle information received here is obtained by correcting the time delay.

  The time delay correcting means detects again the time until the distance obtained by the inter-vehicle communication becomes equal to the actual distance to the preceding vehicle as a time delay (S35). Then, the time delay correcting means transmits the detected time delay to the preceding vehicle (S36).

  The time delay correcting means determines whether or not the time delay has converged within a predetermined range (S37). If the time delay has converged, the process is terminated, and if the time delay is greater than or equal to the predetermined time, the process is repeated from step S31.

  As described above, according to the present embodiment, the time delay correction value is transmitted to the preceding vehicle, and the position in which the preceding vehicle anticipates the time delay and transmitted in advance is transmitted to the host vehicle. Can be converged so that the time delay is reduced. If the time delay in communication with the preceding vehicle is reduced, more advanced control of the inter-vehicle distance becomes possible, such as reducing or increasing the inter-vehicle distance during follow-up traveling.

  The time delay can be automatically corrected by starting the processing of the present embodiment when the time delay is periodically detected or when it is detected that there is a time delay.

  Further, when the position information transmitted from the preceding vehicle does not change despite the increase or decrease in the inter-vehicle distance, it can be detected that there is an error in selecting the preceding vehicle. Therefore, in this case, it is possible to prevent an erroneous selection of the preceding vehicle by performing the preceding vehicle selection process of the first embodiment.

  By the way, the time delay depends on the difference between the in-vehicle system of the preceding vehicle and the system of the own vehicle. Therefore, the time delay will be different if the combination of the vehicles is changed. Therefore, whether or not the time delay has converged is determined based on the time delay before the correction (for example, 1/2 to 1/10 of the time delay before the correction) instead of determining based on a certain value. The effect of the correction can be enhanced for each combination of vehicles by dynamically determining such as.

  When vehicle-to-vehicle communication is realized using light or a relatively high frequency radio wave, it is often limited to communication over a relatively short distance, and a vehicle several hundred meters away with several vehicles in between. It is difficult to communicate with. Therefore, in the inter-vehicle communication, it is possible to realize communication with a relatively distant vehicle by performing a short distance communication between adjacent vehicles and relaying the adjacent vehicles.

  As described in this embodiment, in the state where the preceding vehicle is captured by the ACC and is following the vehicle, the distance between the preceding vehicle and the preceding vehicle is kept substantially constant. Even if the vehicle is transmitted, the preceding vehicle can be received by the preceding vehicle. The preceding vehicle performs vehicle-to-vehicle communication without limiting the radio wave transmission area, or similarly performs vehicle-to-vehicle communication by limiting the radio wave transmission area.

  As described above, if the own vehicle provides the own vehicle information only to the preceding vehicle by limiting the transmission area, it is possible to limit the radio wave arrival distance and contribute to the band reduction.

  FIG. 9 is a flowchart showing a processing procedure in which the own vehicle can change the transmission area of radio waves by inter-vehicle communication. The flowchart in FIG. 9 starts in a state where the vehicle is following by ACC.

  First, the output control means transmits the inter-vehicle distance and the length of the own vehicle to the preceding vehicle by inter-vehicle communication (S51). This inter-vehicle distance may be based on radar or position information.

  The output control means receives other vehicle information from the preceding vehicle by inter-vehicle communication, and determines whether or not the own vehicle information transmitted in step S51 is reflected (S52). Since the preceding vehicle transmits the presence / absence of the vehicle following the vehicle, the number of vehicles following the vehicle traveling, the distance between the vehicles and the connection length according to the vehicle length, to the predetermined area by inter-vehicle communication, the output control means Whether or not the host vehicle information is reflected can be determined based on whether or not the host vehicle information is included in the other vehicle information received from the preceding vehicle.

  When the own vehicle information is not reflected in the preceding vehicle (No in S52), the output control means increases the output of the inter-vehicle communication means 14 by a predetermined amount (S54).

  If the own vehicle information is reflected in the preceding vehicle (Yes in S52), it is determined whether or not the output of the inter-vehicle communication means 14 is equal to or greater than a predetermined value (S53). This predetermined value is the lower limit output value + α for maintaining the vehicle-to-vehicle communication with the preceding vehicle, and includes a slight margin α in the output amount necessary for transmitting radio waves to the preceding vehicle at the minimum. is there.

  If the output of the inter-vehicle communication means 14 is equal to or greater than the predetermined value (Yes in S53), the output control means decreases the output of the inter-vehicle communication means 14 by a predetermined amount (S56). When the output of the vehicle-to-vehicle communication unit 14 is less than the predetermined value (No in S53), the output control unit holds the output of the vehicle-to-vehicle communication unit 14 (S56).

  Thereafter, the process as shown in FIG. 9 is repeated. By repeating the increase and decrease of the output, the output of the inter-vehicle communication can be automatically increased or decreased according to the arrival state of the radio wave, and the power consumption by the inter-vehicle communication can be optimized. Note that such output control can be suitably applied as long as vehicle-to-vehicle communication is possible even if the vehicle is not following the ACC.

  FIG. 10 is a diagram showing a transmission area for inter-vehicle communication adjusted by the output control means. FIG. 10A shows the transmission area before the transmission area is controlled, and FIG. 10B shows the transmission area after the transmission area is controlled.

  In FIG. 10, vehicle A is the preceding vehicle and vehicle B is the host vehicle. Before the transmission area is controlled, both the vehicles A and B are capable of vehicle-to-vehicle communication in the transmission area that covers Area_1. When the output control of the present embodiment is performed from the state of FIG. 10A, the transmission area of the vehicle B can be limited to Area_2 (<Area_1) as shown in FIG. In addition, the bandwidth can be reduced.

  Further, when the inter-vehicle distance increases from the state of FIG. 10 (a) or (b), the output can also be increased. Therefore, the output can be optimized to communicate with the minimum output according to the inter-vehicle distance. It becomes possible.

  As described above, the vehicle position calculation device according to the present embodiment can select a preceding vehicle by inter-vehicle communication when performing follow-up traveling by ACC, and delays time due to communication with the selected preceding vehicle. Can be reduced. Therefore, the preceding vehicle can be selected by inter-vehicle communication, and the communication time delay can be corrected, so that the inter-vehicle distance can be controlled at a high level, such as reducing or increasing the inter-vehicle distance from the preceding vehicle. become. When the inter-vehicle distance is shortened or increased, the transmission output of the inter-vehicle communication can be optimized, so that the output can be reduced and the bandwidth can be reduced.

It is a functional block diagram of a vehicle position calculating device. It is a flowchart figure which shows the flow of the process which determines a preceding vehicle. It is an example of the prescription | regulation table | surface which defines the thickness of a vector. It is a figure which shows an example of the mapped line segment. It is an example of the flowchart figure which shows the evaluation procedure of a coincidence degree. It is a figure which shows an example of the difference of a length difference, an angle, the overlapping degree, and an evaluation point. It is a figure which shows an example of the relationship between a radar vector and a GPS vector. It is a flowchart figure which shows the process sequence which a time delay correction | amendment means converges so that a time delay may decrease during a follow-up driving | running | working. It is a flowchart figure of the process sequence which makes the own vehicle variable the transmission area of the electromagnetic wave by vehicle-to-vehicle communication. It is a figure which shows an example of the transmission area of controlled vehicle-to-vehicle communication.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Arithmetic processing means 11 Perimeter monitoring means 12 Information provision means 13 Vehicle control means 14 Inter-vehicle communication means 15 Navigation means 16 GPS
17 Map database 18 Winker 19 Light 20 Hazard 21 Brake L24 Radar vector G25-26 GPS vector

Claims (8)

Other vehicle position detecting means for detecting the position of the other vehicle mounted on the own vehicle;
Other vehicle position information acquisition means for acquiring other vehicle position information from outside,
Another vehicle selection means for selecting another vehicle of the position information corresponding to the position of the other vehicle detected by the other vehicle position detection means,
The other vehicle selection means includes the first vector indicating the movement amount and direction of the other vehicle detected by the other vehicle position detection means and the position information of the other vehicle acquired by the other vehicle position information acquisition means. Line segment forming means for forming a second vector indicating the amount and direction of movement based on
Detecting the degree of coincidence based on the degree of overlap between the first vector and the second vector formed by the line segment forming means ;
A vehicle position calculation device. The other vehicle selection means detects the degree of coincidence based on the difference in length and angle in addition to the degree of overlap between the first vector and the second vector.
The vehicle position calculation apparatus according to claim 1. The other vehicle position information acquisition means acquires accuracy information indicating the accuracy of the position information,
The line segment forming means changes the thicknesses of the first and second vectors based on the accuracy information.
The vehicle position calculation device according to claim 1 or 2 , characterized in that Corresponding to the accuracy information of the position information, and having a table that defines the thickness information of the second vector that increases as the accuracy of the position information increases ,
The other vehicle selecting means includes a degree of overlap between the first vector formed by the line segment forming means and the second vector whose thickness is corrected according to the thickness information associated with the accuracy information. Detecting the degree of coincidence based on
The vehicle position calculation apparatus according to claim 3. Detecting a time delay of the other vehicle position information acquisition means based on the position information and the own vehicle position;
Time delay correction means for transmitting the detected time delay correction value to the other vehicle selected by the other vehicle selection means;
The vehicle position calculation device according to any one of claims 1 to 4, wherein Output control means for increasing or decreasing the output for communicating with other vehicles selected by the other vehicle selection means;
The vehicle position calculation device according to any one of claims 1 to 5, wherein Vehicle control means for controlling the inter-vehicle distance with the preceding other vehicle;
The time delay correction means is based on the time until distance information equivalent to the inter-vehicle distance instructed to the vehicle control means is acquired by the other vehicle position information acquisition means. Detect delays ,
The vehicle position calculation device according to claim 5. Another vehicle position detection step for detecting the position of another vehicle mounted on the own vehicle;
Other vehicle position information acquisition step for acquiring other vehicle position information from outside,
An other vehicle selection step of selecting another vehicle of the position information corresponding to the position of the other vehicle detected by the other vehicle position detection step,
In the other vehicle selection step, the line segment forming unit obtains the first vector indicating the movement amount and direction of the other vehicle detected in the other vehicle position detection step and the other vehicle position information acquisition step. Forming a second vector indicating a movement amount and a movement direction based on the position information of the car;
Detecting the degree of coincidence based on the degree of overlap between the first vector and the second vector .

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