JP6521753B2 - Vehicle positioning system - Google Patents

Description

The present invention relates to a vehicle positioning system capable of satellite navigation positioning and autonomous navigation positioning.

  In a vehicle such as a car, as a method of measuring the position of the vehicle, satellite navigation that receives and measures signals from navigation satellites such as GPS satellites, and an azimuth angle and relative movement amount detected by a sensor mounted on the vehicle In many cases, two positioning methods with autonomous navigation that is based on positioning are employed. In this case, generally, it is general to switch to the positioning by the autonomous navigation when mainly in the navigation environment which can not receive the signal from the navigation satellite in the tunnel or the like mainly based on the more accurate satellite navigation positioning.

  For example, Patent Document 1 relates to a portable navigation device that does not use a vehicle speed signal from a vehicle, and when the GPS signal can not be received, the second vehicle speed is determined based on the time change of the image captured by the onboard camera. A technique is disclosed that calculates and calculates the vehicle position by autonomous navigation using the second vehicle speed.

JP, 2009-168614, A

  However, even if signals from satellites can be received and positioning can be performed without using autonomous navigation, the accuracy of positioning data obtained by satellite navigation does not necessarily satisfy the required accuracy.

  In particular, in addition to driving support control such as lane departure prevention, lane keeping, and automatic avoidance control of obstacles, development of a system capable of automatic driving that does not require the driver's operation is in progress in recent years. In the case of using the positioning accuracy to simply display the position of the vehicle on the map as in the conventional navigation device, the accuracy is insufficient when using it as data for vehicle control, and it is difficult to use.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle positioning system capable of accurately determining whether positioning data by satellite navigation can be used for vehicle control.

A vehicle positioning system according to an aspect of the present invention is based on a satellite navigation unit that receives a signal from a navigation satellite and measures the position of the vehicle, and an azimuth angle of the vehicle and a relative movement amount from a predetermined position. Autonomous navigation unit that measures the position of the vehicle, a map database that holds map data related to the road on which the vehicle is traveling, and positioning that determines whether the positioning data of the satellite navigation unit can be used for vehicle control And a data availability determining unit, wherein the positioning data availability determining unit is configured such that the number of acquisitions of the navigation satellites is equal to or greater than the number that can be determined, and the positioning accuracy by the acquired navigation satellites is a predetermined accuracy or more. in the lower, the vehicle obtained difference between the positioning data of the positioning data and the autonomous navigation unit of the satellite navigation unit, and the position data of the vehicle and positioning in the satellite navigation unit, from the positioning data of the satellite navigation unit The difference with the map data of the point closest to the vehicle on the traveling lane, the azimuth angle of the vehicle determined by the satellite navigation unit, and the vehicle on the traveling lane of the vehicle determined from the positioning data of the satellite navigation unit Based on the difference with the road azimuth angle at the point closest to the vehicle, it is determined whether the positioning data of the satellite navigation unit can be used for vehicle control.

  According to the present invention, whether or not positioning data by satellite navigation can be used for vehicle control can be accurately determined, and positioning data with insufficient accuracy can be used for vehicle control to reliably prevent occurrence of a problem. be able to.

Configuration diagram of vehicle control system Explanatory drawing showing the change of the positioning accuracy by satellite navigation Flow chart of judgment processing for judging availability of positioning information by satellite navigation

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a vehicle such as a car, and a vehicle control system 2 centering on travel control is mounted on the vehicle 1. The vehicle control system 2 is a communication bus in which the traveling control device 10, the engine control device 20, the brake control device 30, the steering control device 40, the surrounding environment recognition device 50, the map information processing device 60, the positioning device 70, etc. It is configured to be connected to 100.

  In addition, to each control device connected to the communication bus 100 and the communication bus 100, various sensors for detecting an operation state and switches for various settings and operations are connected. FIG. 1 shows an example in which a vehicle speed sensor 6 for detecting a vehicle speed, a yaw rate sensor 7 for detecting a yaw rate, and an azimuth sensor 8 for detecting a traveling direction of the vehicle such as a gyro sensor are connected to the communication bus 100.

  The travel control device 10 enables driving assistance including automatic driving that does not require the driver's operation in response to the driver's driving operation, and can overtake the preceding vehicle, maintain lanes, automatically join highways, etc. Carries out driving support control such as adaptive driving control including automatic avoidance control of obstacles, temporary stop / intersection passing control by detecting signs and signals, emergency evacuation control to the road shoulder at the time of abnormality occurrence, and the like. The driving support control includes the surrounding environment information of the own vehicle recognized by the surrounding environment recognition device 50, the map information from the map information processing device 60, the location information of the own vehicle measured by the positioning device 70, and the vehicle detected by various sensors. It is executed based on the detection information of the traveling state.

  The engine control device 20 is a control device that controls the operating state of a vehicle engine (not shown). For example, the intake air amount, throttle opening degree, engine water temperature, intake temperature, air fuel ratio, crank angle, accelerator opening degree Based on other vehicle information, main control such as fuel injection control, ignition timing control, opening control of electronically controlled throttle valve, etc. is performed.

  The brake control device 30 controls the four-wheel brake system (not shown) independently of the driver's brake operation based on, for example, a brake switch, four-wheel wheel speed, steering wheel angle, yaw rate, and other vehicle information. Do. When the braking force of each wheel is input from the traveling control device 10, the brake control device 30 calculates the brake fluid pressure of each wheel based on the braking force and operates the brake drive unit (not shown). Perform yaw moment control to control the yaw moment applied to the vehicle such as antilock brake system and anti-slip control, and performs yaw brake control.

  The steering control device 40 controls assist torque by an electric power steering motor (not shown) provided in the steering system of the vehicle based on, for example, the vehicle speed, the driver's steering torque, the steering wheel angle, the yaw rate and other vehicle information. The steering control device 40 is capable of lane keeping control for maintaining the own vehicle in the traveling lane and lane departure preventing control for performing departure prevention control for the driving lane. These lane keeping control and lane departure prevention control are possible. The necessary steering angle or steering torque is calculated by the travel control device 10 and input to the steering control device 40, and the electric power steering motor is drive-controlled in accordance with the input control amount.

  The peripheral environment recognition device 50 is a camera device (stereo camera, monocular camera, color camera, etc.) that captures the external environment of the vehicle and processes image information, and a radar that receives reflected waves from three-dimensional objects present around the vehicle. The apparatus (laser radar, millimeter wave radar, ultrasonic radar, etc.) is configured. In the present embodiment, the surrounding environment recognition device 50 detects an object in the front side of the vehicle 1 mainly by the stereo camera unit 3 which stereoscopically captures the front of the vehicle 1 and recognizes an object three-dimensionally from image information. It includes a side radar unit 4 and a rear radar unit 5 using microwaves or the like for detecting an object behind the vehicle 1.

  The stereo camera unit 3 mainly includes, for example, a stereo camera configured by two right and left cameras 3a and 3b installed in the vicinity of a rearview mirror inside a front window at the top of the vehicle interior. The two left and right cameras 3a and 3b are shutter-synchronized cameras having imaging elements such as CCDs and CMOSs, and are fixed at a predetermined base length.

  The stereo camera unit 3 is integrated with an image processing unit that performs stereo image processing on a pair of images captured by the left and right cameras 3a and 3b, and acquires three-dimensional position information of a front object such as a leading vehicle in real space. Are provided. The three-dimensional position of the object is determined, for example, from the parallax data of the object obtained by stereo image processing and the image coordinate value, with the road surface just below the center of the stereo camera as the origin, the X-axis in the vehicle width direction and Y in the vehicle height direction. It is converted into coordinate values in a three-dimensional space with the axis and the vehicle length direction (distance direction) as the Z axis.

  The side radar unit 4 is a proximity radar for detecting an object in a relatively short distance existing around the host vehicle. For example, the side radar unit 4 is installed at the left and right corner portions of the front bumper, and A wave is transmitted to the outside, a reflected wave from an object is received, and a distance and an orientation to an object present on the front side of the own vehicle which is outside the field of view of the stereo camera unit 3 are measured.

  In addition, the rear radar unit 5 is installed, for example, at the left and right corners of the rear bumper, similarly transmits radar waves to the outside to receive reflected waves from objects, and extends to objects lying from the rear to the rear of the vehicle. Measure the distance and direction of

  The map information processing apparatus 60 includes a map database DB, and specifies and outputs the position on the map data of the map database DB from the position data of the own vehicle measured by the positioning device 70. The map database DB includes, for example, navigation map data mainly referred to when displaying route guidance for vehicle travel and the current position of the vehicle, and driving support control including automatic driving more detailed than the map data. The travel control map data to be referred to at the time of execution is held.

  In the map data for navigation, the previous node and the next node are linked to the current node through links, and each link stores information on traffic signals, road signs, buildings, etc. ing. On the other hand, high-definition map data for travel control has a plurality of data points between a node and the next node. The data points include road shape data such as curvature of the road on which the vehicle 1 travels, lane width, road shoulder width, etc., data for road control such as road azimuth, road white line type, number of lanes, etc. And attribute data such as data update date.

  In addition, the map information processing apparatus 60 performs maintenance management of the map database DB, verifies the nodes, links, and data points of the map database DB and constantly maintains the map database DB in the latest state. Create and add new data, and build a more detailed database. Data update of the map database DB and addition of new data are performed by collating the position data measured by the positioning device 70 with the data stored in the map database DB (map matching).

  The positioning device 70 mainly performs satellite navigation that measures the position of the vehicle based on signals from a plurality of satellites, and the capture state of signals (radio waves) from satellites and the influence of multipath due to reflection of radio waves, etc. When the positioning accuracy is deteriorated, the positioning is performed by the autonomous navigation in which the position is determined based on the heading of the vehicle and the movement distance. Therefore, the positioning device 70 includes a satellite navigation unit 70a, an autonomous navigation unit 70b, and a positioning data availability determination unit 70c.

  The positioning device 70 may integrally include a communication unit that acquires traffic information by infrastructure communication such as road-to-vehicle communication or inter-vehicle communication.

  The satellite navigation unit 70a receives a signal including information on orbits and time etc. transmitted from a plurality of navigation satellites 200 such as GPS satellites, for example, and based on the received signal, the own position of the own vehicle is three-dimensionally absolute. Positioning as a position.

  The autonomous navigation unit 70 b compares the calculated position (vehicle position) based on the traveling direction of the vehicle detected by the direction sensor 8 and the movement distance of the vehicle calculated from the vehicle speed pulse and the like output from the vehicle speed sensor 6. Position of the vehicle as a global change.

  The positioning data availability determination unit 70c determines whether or not positioning data of satellite navigation can be used for travel control, and when it is not usable, instructs switching from satellite navigation to positioning by autonomous navigation. For example, when the number of satellites acquired is large and sufficient positioning accuracy can be obtained, or even if the number of satellites acquired is small and high positioning accuracy can be obtained from the arrangement conditions of satellites, positioning data by satellite navigation is used. When a vehicle can not receive a signal from a satellite, for example, when entering a tunnel, it can not acquire the number of satellites necessary to identify its position, or by multipath due to reflection of radio waves by a structure such as a building When the reception accuracy deteriorates, the navigation system switches from satellite navigation to positioning by autonomous navigation, and uses positioning data by autonomous navigation.

  That is, in the positioning of the own position by satellite navigation, as shown in FIG. 2, when the smallest number of satellites from which the position of the vehicle can be calculated can be obtained at time T_1 from the start of positioning at time T_0 The position of the vehicle is determined with an error of the range R_1 centered at 1. After that, when the number of satellites captured increases at time T_2, the error becomes smaller than at time T_1, and the positioning accuracy improves to range R_2. However, when multipath occurs due to the reflection of radio waves at time T_2 ', it is affected As a result, the vehicle position is erroneously positioned as being within a range R 'indicated by a broken line in FIG. It is difficult to remove the error due to this multipath, and if the positioning data at that time is used for travel control, a problem may occur.

  Therefore, the positioning data availability determination unit 70c determines whether or not the following conditions (A) to (D) are satisfied. And, assuming that both the conditions of (A) and (B) are satisfied, if the conditions of (C) and (D) are both satisfied, positioning data by satellite navigation is used for traveling control. If it is determined that it is possible, and either of the conditions (C) and (D) is not satisfied, it is determined that positioning data by satellite navigation can not be used for travel control.

(A) The number of satellites captured is equal to or greater than the threshold THN Generally, in satellite navigation that determines the position of the vehicle in a three-dimensional space based on signals from multiple satellites such as GPS, the distance to the satellite is Since the arrival time is calculated, a minimum of four satellites are required for the amount of deviation between the three-dimensional position and the time on the receiver side. Therefore, assuming that the threshold number THN of the required number of satellites is 4, it is possible to use positioning data when the number N of satellites captured after the start of positioning is N ≧ 4, and not available when N <4.

(B) Positioning accuracy of satellite navigation is higher than a predetermined value Positioning accuracy of satellite navigation is influenced by the arrangement of satellites captured with respect to the measurement point (vehicle position). The degree to which the positioning accuracy is reduced due to the arrangement of the satellites with respect to the measurement point can be evaluated by the well-known Dilution Of Precision (DOP) obtained on the receiving side. As the DOP value decreases, the positioning accuracy increases, and as the DOP value increases, the positioning accuracy decreases.

  In the present embodiment, in the DOP, using the horizontal dilution of precision (HDOP), if the HDOP value is less than or equal to the preset threshold THdop, the positioning data by satellite navigation is If available, the threshold value is exceeded, positioning data by satellite navigation is disabled.

(C) The difference between the positioning data of satellite navigation and the positioning data of autonomous navigation is less than the threshold value THDL. The difference (distance) between the position data of the host vehicle determined by satellite navigation and the position data of the host vehicle determined by autonomous navigation. It is checked whether it is within the range below the threshold value THDL. If the difference value DL between the satellite navigation position data and the autonomous navigation position data is less than or equal to the threshold value THDL, the satellite navigation positioning data can be used, and the difference value DL exceeds the threshold value THHD and the difference between the two is large. If it does, satellite navigation positioning data can not be used.

  In this case, since the positioning data by satellite navigation is coordinate data of the global geodetic system, coordinate conversion of the geodetic system is required to calculate the difference from the positioning data of the autonomous navigation. Therefore, the threshold value THDL must be set in consideration of the conversion error, and there is a possibility that it may be determined as unusable even though the satellite navigation positioning data has reached the usable accuracy. In addition, although the positioning state of the satellite navigation is not good, the difference between the positioning data of the satellite navigation and the positioning data of the autonomous navigation becomes equal to or less than the threshold value THHD due to the influence of multipath etc. There is also sex. Therefore, in the present embodiment, it is further checked whether the following conditions (C1) and (C2) are satisfied.

(C1) The difference in the amount of change in distance is equal to or less than the threshold THDd Every time the positioning data is updated, the amount of change (distance) in satellite navigation position data and the autonomous navigation The difference with the change amount (distance) of the position data is calculated, and the difference value Dd is compared with the threshold value THDd. When the difference value Dd is equal to or less than the threshold THDd, positioning data by satellite navigation can be used. When the difference THd exceeds the threshold THDd, positioning data by satellite navigation can not be used.

(C2) Difference in azimuth angle is equal to or less than the threshold THθ Every time the positioning data is updated based on the point in time when positioning by satellite navigation is started, it is obtained by the variation of azimuth angle obtained by satellite navigation and integrated value of yaw rate. The difference (angle) with the amount of change of the azimuth angle by the autonomous navigation is calculated, and the difference value Dθ is compared with the threshold value THθ. When the difference value Dθ is equal to or less than the threshold THθ, the positioning data by satellite navigation can be used. When the difference value Dθ exceeds the threshold THθ, the positioning data by satellite navigation can not be used.

(D) The difference between the positioning data of satellite navigation and the map data is less than the threshold. Usually, even if the position of the vehicle is determined by the autonomous navigation except for specific data points and the past history, the corresponding data in the map database DB Does not exist and can not be compared directly. Therefore, in the present embodiment, the traveling lane of the vehicle is obtained from the positioning data by satellite navigation, and the data point on the map closest to the vehicle position of satellite navigation is searched on this traveling lane.

  Then, the difference between the positioning data of satellite navigation and the data of the closest map data point on the traveling lane is calculated, and compared with the threshold value. The difference data at this time is calculated with both distance and angle, as shown in (D1) and (D2) below, and each difference value is compared with the respective threshold value.

(D1) The difference in distance is equal to or less than the threshold THDm The difference (distance) between the position data of the host vehicle determined by satellite navigation and the position data of a point on the map approaching on the host vehicle lane is calculated. When Dm is equal to or less than the threshold THDm, positioning data by satellite navigation can be used, and when the threshold THDm is exceeded, positioning data by satellite navigation can not be used.

(D2) Difference in azimuth is equal to or less than threshold TH θm Calculate the difference (angle) between the azimuth of the vehicle obtained by satellite navigation and the road azimuth at a point on the map that is close on the vehicle travel lane, When the difference value Dθm is less than or equal to the threshold THθm, positioning data by satellite navigation can be used, and when exceeding the threshold THθm, positioning data by satellite navigation can not be used.

  Specifically, the availability of the positioning data by satellite navigation is determined by program processing shown in the flowchart of FIG. Next, a determination process of determining whether the positioning information can be used by satellite navigation will be described.

  In this determination process, in the first step S1, it is checked whether the condition that the number N of satellites captured after the start of positioning is equal to or more than the threshold THN is satisfied. Then, in the case of NN ス テ ッ プ THN, it is checked in step S2 whether the rate of decrease in accuracy in the horizontal direction (HDOP) in satellite navigation is less than or equal to the threshold THdop. If HDOP is less than or equal to the threshold THdop, the process proceeds to step S3 and later.

  Steps S3 to S5 are processings for comparing satellite navigation and autonomous navigation to determine whether or not satellite navigation positioning data can be used. First, in step S3, a difference value DL (distance) between the vehicle position data of satellite navigation and the vehicle position data of autonomous navigation is calculated, and whether the difference value DL satisfies the condition of being less than or equal to the threshold value THL. Examine

  Then, in the case of DL ≦ THDL, the amount of change (distance) in the position data of the satellite navigation and the position of the autonomous navigation every time the positioning data is updated based on the time when the positioning of the satellite navigation is started in step S4. The amount of change (distance) of the data is obtained, and the difference value Dd of the amounts of change between the two is calculated. Then, it is checked whether the condition that the difference value Dd is equal to or less than the threshold THDd is satisfied.

  In step S4, in the case of Dd ≦ THDd, the amount of change in the satellite navigation azimuth and the integrated value of the yaw rate each time the positioning data is updated with reference to the point in time positioning of satellite navigation is started in step S5. The difference value Dθ with the amount of change in the azimuth of the autonomous navigation obtained in Then, it is checked whether the condition that the difference value Dθ is equal to or less than the threshold THθ is satisfied, and in the case of Dθ ≦ THθ, the process proceeds to step S6 and subsequent steps.

  Steps S6 and S7 are processes of comparing positioning data of satellite navigation with map data to determine whether positioning data of satellite navigation can be used. That is, in step S6, the difference (distance) between the vehicle position data of satellite navigation and the position data on the closest map on the vehicle travel lane is calculated, and the condition that the difference value Dm is less than the threshold THDm Find out if you are satisfied.

  If Dm ≦ THDm in step S6, the difference (angle) between the azimuth of the vehicle obtained by satellite navigation in step S7 and the road azimuth at the closest map point on the vehicle travel lane is further calculated. Then, it is checked whether the condition that the difference value Dθm is equal to or less than the threshold THθm is satisfied.

  As a result, if Dθm ≦ THθm in step S7 and all the conditions in steps S1 to S7 are satisfied, the process proceeds to step S8. In step S8, the positioning data by satellite navigation has reached the accuracy that can be used for travel control, and it is determined that the positioning data by satellite navigation is usable.

  Based on the determination that the positioning data of the satellite navigation can be used, the travel control device 10 performs position information of the vehicle determined by satellite navigation, surrounding environment information of the vehicle recognized by the surrounding environment recognition device 50, map information Based on the map information from the processing device 60 and the detection information of the vehicle traveling state detected by various sensors, driving support control including automatic operation and automatic braking is executed. Further, in the map information processing apparatus 60, the update of the map database DB is judged by the positioning data of satellite navigation.

  On the other hand, if any one of the conditions in steps S1 to S7 is not satisfied, the process proceeds from step S9 to step S9, and the positioning data by satellite navigation has not reached the accuracy usable in travel control and is not usable. judge. When it is determined that the positioning data of satellite navigation can not be used, the traveling control apparatus 10 receives the determination of the use prohibition and uses the position information of the own vehicle determined by autonomous traveling instead of the satellite navigation. Carries out relatively mild driving support control.

  As described above, in the present embodiment, based on the difference between the positioning data by satellite navigation and the positioning data by autonomous navigation and the difference between the positioning data by satellite navigation and the map data of the map database, the positioning data by satellite navigation is Whether or not it can be used for vehicle control can be accurately determined, and positioning data with insufficient accuracy can be used for vehicle control to reliably prevent occurrence of a problem.

1 vehicle 6 vehicle speed sensor 7 yaw rate sensor 8 direction sensor 10 travel control device 20 engine control device 30 brake control device 40 steering control device 50 peripheral environment recognition device 60 map information processing device 70 positioning device 70a satellite navigation unit 70b autonomous navigation unit 70c positioning Data availability judgment part 200 navigation satellite DB map database

Claims (3)

A satellite navigation unit that receives a signal from a navigation satellite and determines the position of the vehicle;
An autonomous navigation unit that measures the position of the vehicle based on an azimuth angle of the vehicle and a relative movement amount from a predetermined position;
A map database which holds map data relating to the road on which the vehicle travels;
A positioning data availability determination unit that determines whether the positioning data of the satellite navigation unit can be used for vehicle control;
The positioning data availability determination unit
Under the condition that the number of acquisitions of the navigation satellites is equal to or more than the number that can be determined, and the positioning accuracy by the acquired navigation satellites is a predetermined accuracy or more,
The difference between the positioning data of the satellite navigation unit and the positioning data of the autonomous navigation unit, the position data of the vehicle measured by the satellite navigation unit, and the traveling lane of the vehicle calculated from the positioning data of the satellite navigation unit The difference from the map data of the point closest to the vehicle, the azimuth angle of the vehicle determined by the satellite navigation unit, and the vehicle closest to the vehicle on the traveling lane of the vehicle determined from the positioning data of the satellite navigation unit It is determined whether the positioning data of the said satellite navigation part can be used for vehicle control based on the difference with the road azimuth angle in a point . The positioning system of the vehicle characterized by the above-mentioned. The positioning data availability determination unit may
The difference between the variation of the positioning data of the satellite navigation unit and the variation of the positioning data of the autonomous navigation unit is used as the difference between the positioning data of the satellite navigation unit and the positioning data of the autonomous navigation unit. The positioning system of the vehicle according to claim 1 . The positioning data availability determination unit may
As a difference between the positioning data of the satellite navigation unit and the positioning data of the autonomous navigation unit, a difference between an azimuth angle determined by the satellite navigation unit and an azimuth angle determined by the autonomous navigation unit is further used. The positioning system of the vehicle according to claim 2 .

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