JP2007218848A - Positional information acquisition system for mobile body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability when vehicle control etc. is applied with, by highly accurately acquiring information on a current self-position. <P>SOLUTION: A self-vehicle position computation part 10 positions the current position in the actual world of an own vehicle on the basis of signals from a GPS sensor 3; an orientation sensor 4; and a distance sensor 5. A map matching processing part 12 estimates a road, in which the own vehicle is traveling by a pattern matching technique. A safety control processing part 13 uses detection results (distance between the self-vehicle and a field object of which the absolute position is known) from a radar 7, determines the position of the presence of own vehicle again on the estimated road, to specify the current position, computes the reliability of information on the determined current position of the self-vehicle, and outputs these items of information to a light control part 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a position information acquisition device for a moving body that is provided in a moving body such as a vehicle that moves on a road and that acquires its current position information.

  As this type of moving body position information acquisition device, there is a car navigation system mounted on a vehicle such as an automobile. This car navigation system measures the absolute position of the vehicle based on reception of radio waves from a GPS satellite by a GPS receiver, and corrects the position based on detection by a vehicle speed sensor or a gyro sensor. The absolute position (and the traveling direction) of the vehicle is measured with high accuracy. In addition, a location function that displays the vehicle's position and direction of travel on the display screen superimposed on a map, a route guidance function that searches for and guides the recommended route to the destination specified by the user, etc. It is supposed to be.

In this case, in general, in order to implement the location function, in order to place the position of the own vehicle on the road on the displayed electronic map, the movement locus of the own vehicle is compared with the road shape in the road map data. Thus, map matching for estimating the currently running road is performed. Conventionally, various methods have been proposed as such map matching methods (see, for example, Patent Document 1 and Patent Document 2).
JP 9-304093 A JP-A-2005-207821

  By the way, in the car navigation system described above, the accuracy of the electronic map drawn on the screen of the display device based on the road map data is considerably inferior to that of an actual road. Conventional car navigation systems place importance on determining and displaying the relative position of the own vehicle along the road shape of the electronic map, which is inferior in accuracy, from highly accurate position information of the own vehicle. In other words, in the conventional map matching method, it is important to determine the road on which the vehicle is traveling, and the positional information accuracy in the front-rear direction on the road has not been emphasized so much.

  On the other hand, in recent years, it has been considered to link a car navigation system and vehicle control. As a specific example, based on the curve information from the car navigation system, when the host vehicle approaches the curve, the direction of the headlight of the vehicle is automatically controlled so that it faces the other side of the curve. It has been. However, as described above, the positional information accuracy in the front-rear direction on the road of the own vehicle is low, and the degree of error is unknown, so that it is difficult to apply to vehicle control in terms of reliability. This becomes more problematic as vehicle control proceeds in the direction of safe driving.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain the current position information with high accuracy, and thus to improve the reliability when applied to vehicle control, for example. The object is to provide a body position information acquisition device.

  The mobile body position information acquisition apparatus of the present invention is based on a storage means for storing road map data, a positioning means for positioning its current position, a positioning result by the positioning means, and the road map data. An estimation means for estimating a moving road, a position specifying means for re-determining the current position on the road estimated by the estimation means, and a current position determined by the position specifying means A reliability calculating means for calculating the reliability of the position information; and an output means for outputting the current position information determined by the position specifying means together with the reliability information calculated by the reliability calculating means. It has characteristics (invention of claim 1).

  In the present invention, the detection (specification) of the position of the mobile object is performed by positioning the current position by the positioning unit, estimating the road on which the moving unit is moving, estimating the position on the estimated road by the position specifying unit. The determination is made through three steps of re-determining the existence position of. At this time, by providing the position specifying means, it is not limited to simply determining the road on which the self is moving, and the position of the self on the road will be more precisely specified by the determination again, Accordingly, the accuracy of the current position information can be improved. At the same time, the reliability of the current position information is calculated by the reliability calculation means, and the reliability information is added to the current position information in the information output from the output means. Therefore, the reliability information serves as a standard for determining how to use the current position information (or whether or not to use the current position information), and as a result, the reliability when applied to, for example, vehicle control can be improved.

  More specifically, the position specifying means can be configured to specify its own location based on performing map matching by a projection method (invention of claim 2). As a result, it is possible to determine again the location of the user on the road by a simple process. Alternatively, the position specifying means may be configured to specify the self-existing position based on detecting the relative position of the self with respect to an external fixed object whose absolute position is known by the detecting means. (Invention of Claim 3). According to this, it is possible to determine the presence position of the self with higher accuracy.

  Further, the reliability calculation means can be configured to calculate the reliability based on the positioning accuracy in the positioning means and the correction error of the current position specified by the position specifying means (claim 4). invention). The reliability according to the error between the apparent self-position estimated on the electronic map and the identified self-position with high accuracy can be calculated.

  By the way, there is a deviation (delay) between the time measured by the positioning means and the time when the information output by the output means is used, and the current position changes during that time. Will be invited. Therefore, if the reliability information is configured to include time information at the time of positioning by the positioning means (invention of claim 5), it is possible to determine the deterioration of reliability due to time lag, and the deterioration of accuracy. It is also possible to correct this.

  Hereinafter, an embodiment in which the present invention is applied to an in-vehicle device in which a car navigation system and vehicle control are linked will be described with reference to the drawings. FIG. 1 schematically shows a main configuration of an in-vehicle device 1 as a moving body position information acquisition device according to the present embodiment. This in-vehicle device 1 is mounted on a vehicle (automobile) as a moving body, and is configured by connecting a control unit 2 with a GPS sensor 3, a direction sensor 4, a distance sensor 5, a map database 6, a radar 7, and the like. . In this embodiment, a light control unit 9 is connected to the control unit 2 via an in-vehicle network (in-vehicle LAN) 8.

  Among them, the control unit 2 is mainly composed of a microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and controls the entire vehicle-mounted device 1. As will be described in detail later, the functions of the vehicle position calculation unit 10, the travel locus memory 11, the map matching processing unit 12, and the safety control processing unit 13 are realized by the software configuration (and hardware configuration). It has become.

  The GPS sensor 3 includes a receiver that receives a signal from a GPS satellite, and detects the current position (latitude, longitude) and time of itself (the vehicle) with high accuracy based on the received signal. Yes. The direction sensor 4 is a sensor that detects the traveling direction of the host vehicle, and the distance sensor 5 is a sensor that measures the travel distance of the host vehicle. The signals from these position detection sensors 3 to 5 are input to the vehicle position calculation unit 10 of the control unit 2.

  The map database 6 stores, for example, road map data all over Japan, facility data associated therewith, and the like, and functions as storage means. The road map data is given as link data in which a road on a map is divided into a plurality of parts using intersections as nodes and the parts between the nodes are defined as links. This link data includes data such as a link-specific link ID (identifier), link length, link start point and end point position data, angle (direction) data, road width, and road type. Data for reproducing the road map on the screen of the display device is also included.

  The radar 7 measures a distance from an object (including another traveling vehicle) located in front of the own vehicle based on, for example, microwave irradiation and detection of the reflected wave. In the present embodiment, the distance (by extension) between an external fixed object whose absolute position is known by the radar 7 (for example, a recognition target provided on a traffic signal on a road or a specific building) and the own vehicle. Relative position) is detected, and functions as a detecting means as will be described later. The detection signal of the radar 7 is input to the safety control processing unit 13 of the control unit 2. Instead of the radar 7, a monitoring camera, an ultrasonic sensor, a laser sensor, or the like may be employed.

  In addition, although illustration is abbreviate | omitted, in this vehicle-mounted apparatus 1 (control part 2), the display apparatus which can display navigation screens, such as a map, the operation switch part for a user to perform various operation instructions, etc., audio | voice An audio output device for performing guidance and the like, and a wireless communication unit that acquires road traffic information and the like by communication with the outside (VICS (registered trademark) center or the like) are connected. As a result, a location function that displays the current position (and direction of travel) of the vehicle along with the road map on the display device and automatically calculates a recommended travel route to the destination specified by the user A normal navigation function such as a route guidance function for guiding the user is realized.

  In the present embodiment, the in-vehicle device 1 (control unit 2) acquires the position information of the own vehicle, and outputs the position information and the like to the light control unit 9 via the in-vehicle LAN 8. Yes. The light control unit 9 automatically controls the headlight of the own vehicle. For example, the light control unit 9 controls turning on and off of the headlight based on the detection of the brightness outside the vehicle, and the control unit 2 (safety control processing unit). The direction (irradiation direction) of the headlight is adjusted according to the current position information (and front road information) of the host vehicle input from 13).

  As will be described later in the description of the operation, when the in-vehicle device 1 (control unit 2) obtains the position information of the own vehicle, first, the own vehicle position calculation unit 10 of the control unit 2 includes the GPS sensor 3, the direction sensor, 4. Based on the signal from the distance sensor 5, the current position of the vehicle in the real world (actual) at every time t is calculated (positioning), and the running data for the elapsed time t from the previous time is calculated. Information on the positioning result of the current position is notified to the map matching processing unit 12 and the safety control processing unit 13, respectively. At this time, information on reliability (positioning accuracy) resulting from errors of the sensors 3 to 5 and time information at the time of positioning are also notified. The traveling data is given to the traveling locus memory 11 and stored as traveling locus data.

  Next, the map matching processing unit 12 is based on the positioning result of the current position given from the own vehicle position calculation unit 10, the traveling locus data stored in the traveling locus memory 11, and the road map data obtained from the map database 6. A road on which the vehicle is traveling (which link is traveling) is estimated by a known pattern matching method. The information (link data) of the estimated traveling road of the own vehicle is notified to the safety control processing unit 13.

  The safety control processing unit 13 is information on the traveling road (link data) given from the map matching processing unit 12, information on the positioning result given from the vehicle position calculation unit 10, road map data obtained from the map database 6, and Based on the detection result from the radar 7 (the relative position of the vehicle with respect to a fixed object whose absolute position is already known), the position of the vehicle on the estimated road is determined again.

  At the same time, the safety control processing unit 13 calculates the reliability of the determined position information of the own vehicle. In this case, the reliability is calculated based on the positioning accuracy information in the vehicle position calculation unit 10 and the correction error between the position of the vehicle estimated in the map matching processing unit 12 and the determination result. In addition, the reliability information includes time information at the time of positioning in the vehicle position calculation unit 10.

  The safety control processing unit 13 outputs the determined position information of the own vehicle to the light control unit 9 together with the reliability information. Accordingly, the sensors 3 to 5 for position detection and the vehicle position calculation unit 10 function as positioning means. Further, the map matching processing unit 12 functions as an estimation unit. The safety control processing unit 13 functions as a position specifying unit, a reliability calculation unit, and an output unit.

  The safety control processing unit 13 calculates road information (curve starting point, curve radius of curvature, etc.) of the current position of the host vehicle and outputs it to the light control unit 9 as necessary. ing. The light control unit 9 performs control such as adjusting the headlight direction so as to illuminate the other side of the curve according to the position information (forward road information) input from the safety control processing unit 13. At that time, the degree of control is determined according to the reliability information.

  Next, the operation of the above configuration will be described with reference to FIGS. The flowchart of FIG. 2 shows an outline of the entire processing procedure for acquiring the current position information of the host vehicle executed by the control unit 2. The flowcharts of FIGS. 3, 4, and 5 show details of the processing procedures of steps S1, S2, and S3 of FIG. 2, respectively. FIG. 6 shows the overall data flow at that time. Hereinafter, these flowcharts will be described in order.

  As shown in FIG. 2, when acquiring the current position information of the own vehicle, first, in step S1, the current position calculation (positioning) in the real world (actual) of the own vehicle is performed by the own vehicle position calculation unit 10. Executed. In the next step S2, the map matching processing unit 12 estimates the road on which the vehicle is traveling. In step S3, the safety control processing unit 13 specifies the current position based on re-determination of the position of the vehicle on the estimated road. In step S3, the reliability of the current position information is also calculated.

  In FIG. 3 which shows the detailed process sequence of said step S1, in step S11, the signal from the GPS sensor 3, the direction sensor 4, and the distance sensor 5 is input. In subsequent step S12, the signals from the respective sensors 3 to 5 are corrected by an appropriate filter. In step S13, the current position (absolute position) in the real world (actual) of the host vehicle is calculated (positioning) from the corrected data, the absolute direction in which the host vehicle is traveling, and the time t from the previous positioning. The travel distance between them and the relative orientation from the previous time are calculated.

  Calculated current position data (for example, latitude, longitude, altitude), absolute bearing data (for example, coordinates (A, B) to coordinates (C, D)), travel distance data (for example, 1.6 m) The relative azimuth data (for example, right front 45 degrees) is output with the prediction error (positioning accuracy) and time information added.

  Next, in FIG. 4 showing the detailed processing procedure of step S2, first, in step S21, the initial position is determined using the data obtained from the vehicle position calculation unit 10. In step S22, map matching (pattern matching) processing is performed on the basis of the data of the travel trajectory stored in the travel trajectory memory 11 and the road map data read from the map database 6. The road on which the vehicle is located (running) is estimated.

  In this case, as illustrated in FIG. 7, the current position data in the measured real world is indicated by a black circle, and when there are two roads 1 and 2 on the electronic map, It is estimated that the vehicle is traveling at the position indicated by the white circle on the road 2 by map matching. When the traveling road on the map is estimated, the data of the identifier (link ID) of the road is output together with the time information at the time of estimation. At this time, it can be said that the reliability (accuracy) of the estimated road is close to 100%, but if possible, data of a prediction error (reliability of estimation of the traveling road) may be added. .

  In FIG. 5 showing the detailed processing procedure of step S3, first, in step S31, data such as the current position measured in step S1 (S13) and the road identifier obtained in step S2 (S22). Etc. are input. In step S32, based on the detection of the radar 7 (detection of the distance between the recognition target provided in the traffic light whose absolute position is known and the host vehicle), the position of the host vehicle is determined again, The current position on the road on which the vehicle is traveling is specified. By this specification, as illustrated in FIG. 7, the position of the vehicle is corrected from the position indicated by a white circle to the position indicated by an asterisk.

  In the next step S33, based on the prediction error (positioning accuracy) included in the absolute position information calculated in step S1 and the correction error (degree of position correction) of the current position specified in step S32. Thus, the reliability of the current position on the map of the identified own vehicle is calculated. This reliability can be expressed by a numerical value indicating, for example, how many meters the error is, expressed by%, or expressed by a rank such as high, medium, or low.

  In step S34, when necessary in the light control unit 9, road information ahead of the current position of the vehicle on the map is read from the map database 6. In step S35, the reliability information and time information obtained in step S33 are added to the current position information on the map of the vehicle specified in step S32 and output to the light control unit 9. At this time, if necessary, the road information ahead of the current position of the vehicle read in step S34 is also output, and the process ends.

  As shown only in FIG. 6, the light control unit 9 can control the headlight based on the current position information, reliability information, time information, and forward road information on the map of the vehicle. At this time, it is possible to determine whether or how much the current position information is used for control according to the reliability. Furthermore, since the time information at the time of positioning is included, it is possible to determine deterioration of reliability information due to a time lag when performing control, and it is also possible to correct the deterioration of accuracy. Also in the navigation function, the current position on the map of the host vehicle can be displayed more accurately on the display device based on the current position information specified in step S32.

  Thus, according to the present embodiment, the detection (specification) of the current position of the own vehicle is performed by positioning the current position of the own vehicle, estimating the road on the map on which the own vehicle is moving, and the own vehicle on the estimated road. It is made to go through three steps of re-determining the existence position of. As a result, the current position of the vehicle on the road is more precisely identified by re-determination, not just determining the road (link) on which the vehicle is moving. The current position information of the own vehicle can be obtained with high accuracy.

  In addition, the reliability of the current position information is calculated, and the reliability information is added to the current position information and output. Therefore, the reliability information serves as a standard for determining how to use (or whether or not to use) the current position information, and as a result, reliability when applied to vehicle control can be improved. Furthermore, since the time information at the time of positioning is included in the reliability information, it is possible to determine the deterioration in reliability due to the time lag, and to correct the deterioration in accuracy.

  In particular, in this embodiment, the determination of the position of the own vehicle on the estimated road is performed again using the radar 7 to detect the distance between the fixed object whose absolute position is known and the own vehicle. Since this is performed based on the above, it is possible to determine (specify) the location of the own vehicle with higher accuracy.

  In the above embodiment, the determination (specification) of the position of the own vehicle on the estimated road is performed again by the relative position of the own vehicle with respect to an external fixed object whose absolute position is known by the detection means (radar 7) ( However, it may be configured to specify the location of the own vehicle based on map matching using a projection method. According to this, it is possible to determine again the location of the own vehicle on the estimated road by a simple process, and it can also be performed in a place where infrastructure related to a fixed object is not prepared. It is also possible to determine (specify) the vehicle position again by combining a plurality of methods.

  In the above embodiment, the headlight control is given as a specific example of the vehicle control using the current position information. In addition, the current position information of the own vehicle is used for air conditioner control, brake control, etc. You can also. In addition, the present invention is not limited to an in-vehicle device that links a car navigation system and vehicle control, for example, and the present invention can be applied to a pedestrian navigation system that a pedestrian possesses. The present invention is not limited to the examples, and can be implemented with appropriate modifications without departing from the scope of the invention.

The block diagram which shows one Example of this invention and shows the whole structure roughly The flowchart which shows the outline of the whole process of acquisition of the present position information of the own vehicle Flow chart showing the detailed processing procedure for positioning the current position of the host vehicle The flowchart which shows the detailed processing procedure of estimation of the road where the own vehicle is traveling The flowchart which shows the specific detailed process sequence of the existing position of the own vehicle on an estimated road The figure which shows the data flow in the acquisition process of the present position information of the own vehicle Diagram showing an example of map matching

Explanation of symbols

  In the drawings, 1 is a vehicle-mounted device (position information acquisition device for moving body), 2 is a control unit, 3 is a GPS sensor, 4 is a direction sensor, 5 is a distance sensor, 6 is a map database (storage means), and 7 is a radar ( Detection means), 9 a light control section, 10 a vehicle position calculation section (positioning means), 12 a map matching processing section (estimation means), 13 a safety control processing section (position specifying means, reliability calculation means, output) Means).

Claims (5)

A device that is provided on a moving body that moves on a road and that acquires current position information of itself,
Storage means for storing road map data;
Positioning means for positioning the current position of the self,
Based on the positioning results by the positioning means and the road map data, estimating means for estimating the road on which the user is moving;
A position specifying means for re-determining the position of the person on the road estimated by the estimating means and specifying the current position;
Reliability calculation means for calculating the reliability of the current current position information determined by the position specifying means;
A moving body position information acquisition apparatus comprising: output means for outputting current position information determined by the position specifying means together with reliability information calculated by the reliability calculation means.   2. The position information acquisition apparatus for a moving body according to claim 1, wherein the position specifying means specifies the position of the self based on performing map matching by a projection method.   2. The position specifying means specifies the presence position of the self based on detecting a relative position of the self with respect to an external fixed object whose absolute position is known by the detecting means. The position information acquisition apparatus for moving bodies described.   4. The reliability calculation unit according to claim 1, wherein the reliability calculation unit calculates the reliability based on a positioning accuracy in the positioning unit and a correction error of a current position specified by the position specifying unit. The position information acquisition apparatus for moving bodies described.   5. The moving body position information acquisition apparatus according to claim 1, wherein the reliability information includes time information at the time of positioning by the positioning means.

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