JP2003322534A - Location device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a location device capable of determining a present position near the actual present position when and after a moving body passes through a branch, especially near a narrow-angle branch. <P>SOLUTION: This device includes an absolute position detection part 11 for detecting the absolute position and the absolute azimuth of the driver's own car, a displacement detecting part 12 for detecting the moving quantity and a relative azimuth of the driver's own car, a road database part 13 for storing information of roads movable thereon by an automobile, and a processing part 14 for determining the present position of the driver's own car correlatively with the road based on at least either of the detected absolute position by the absolute position detection part 11 and the detected moving quantity by the displacement detection part 12, and on the road information in the road database part 13. When the driver's own car passes near a branch point of the road, the processing part 14 performs absolute position-weighted processing for weighting so that the weight of the detected absolute position becomes larger, and determining the present position of the driver's own car. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a location device that indicates the current position of a mobile body.

[0002]

2. Description of the Related Art A location device such as a car navigation device mounted on a moving body such as a vehicle uses a global positioning system (Global Positioning System) as a means for detecting an absolute position of the moving body in order to obtain a current position. Sys
tem; abbreviated name: GPS) and a speed sensor and a gyro are used as means for detecting the amount of movement of the moving body.

Due to the precision of these GPS, speed sensor and gyro, the current position of the moving body is obtained mainly based on the detection results of the speed sensor and gyro, and the speed sensor is regularly used to detect the speed sensor. Further, the detection result of the gyro is corrected to obtain a more accurate current position of the moving body.

As such a conventional technique, for example, Japanese Unexamined Patent Publication No. 2000-146607 discloses a navigation device for obtaining a more accurate traveling position of a vehicle even when the road has a shallow branching angle and continues to run in parallel. Is disclosed. As another conventional technique, Japanese Patent Laid-Open No. 619/1996
Japanese Unexamined Patent Publication No. 70 discloses a vehicle-mounted navigation device that determines and deletes unnecessary current position candidates by appropriate determination even at times other than branching. Still another conventional technology is
Japanese Patent Laid-Open No. 11-37776 discloses a vehicular navigation device that improves the accuracy in determining the position of a vehicle on the road.

[0005]

In a location device using a GPS, a speed sensor and a gyro, a gyro is passed when passing through an angled branch where the angle formed by the paths branched by a moving body is, for example, 15 degrees or less. Since it is difficult to detect a minute azimuth change due to, it is difficult to accurately obtain the current position of the moving body. In addition, since the information stored in the route database provided in the location device is represented by the route in which the mobile body can move by the link that divides the route into line segments and the node that connects the links, Since the angle between the azimuth of the moving body and the azimuth of the link is small and the distance between the position of the moving body and the link is short, when there are multiple candidates for the current position of the moving body by map matching, the superiority or inferiority of those candidates. It is difficult to attach the current position candidate, and it is not possible to immediately change the current position candidate that is different from the accurate current position to the current position candidate that is the accurate current position.

The navigation device disclosed in Japanese Unexamined Patent Publication No. 2000-146607 obtains a more accurate traveling position of a vehicle even at a narrow angle branch, but detailed processing in the narrow angle branch is not shown. . Further, since the vehicle-mounted navigation device disclosed in Japanese Patent Laid-Open No. 8-61970 does not use the absolute position by GPS or the like based only on the detection results of the vehicle speed sensor and the direction sensor,
Precision cannot be expected very much. In addition, JP-A-11-3777
The vehicle navigation device disclosed in Japanese Patent No. 6 is not shown with respect to a method for obtaining a current position when a moving body passes through a narrow angle branch.

Therefore, an object of the present invention is to provide a location device capable of determining a current position close to an actual current position when and after a moving body passes a branch, especially near a narrow angle branch. Is.

[0008]

The invention according to claim 1 is
In a location device comprising an absolute position detecting means for detecting an absolute position of a moving body, a displacement detecting means for detecting a moving amount of the moving body, and a route database means for storing information on a route along which the moving body can move. The current position of the moving body is associated with the route based on at least one of the absolute position detected by the absolute position detection unit and the movement amount detected by the displacement detection unit, and the route information of the route database unit. The position determining means determines the current position of the moving body by weighting so that the weight of the detected absolute position becomes large when the moving body passes near the branch point of the route. The location device is characterized by performing an absolute position-oriented process.

According to the first aspect of the invention, when the moving body passes near the branch point of the route, weighting is performed so that the weight of the detected absolute position detected by the absolute position detection means becomes large, and at least Based on the detected absolute position weighted in this way and the route information of the route database means, an absolute position-oriented process for determining the current position of the moving body in association with the route is performed. When the moving body passes near the branch point, the accuracy of detection of the amount of movement of the moving body by the displacement detecting means becomes lower than when passing other than near the branch point, or more than the detection accuracy of the absolute position detecting means. Since it becomes low, even if the current position of the moving body is determined based on such a low-precision detected movement amount, it may differ from the actual current position. Therefore, when the moving body passes near the branch point, the weight of the detected absolute position detected by the absolute position detection means is weighted so as to increase the influence of the low-precision detected movement amount on the determination of the current position. Can be made small so that the determined current position can be as close as possible to the actual current position.

The invention according to claim 2 further includes detection result determination means for determining whether the detection result of the absolute position detection means is normal or abnormal, and the position determination means includes the absolute position detection means. When it is determined that the detection result of is abnormal, when the moving body passes near the branch point of the route, the weight of the detection result detected by the absolute position detection means and the detection result of the displacement detection means is set. It is characterized in that equal processing is performed to make the current positions of the moving bodies equal.

According to the invention of claim 2, when it is determined that the detection result of the absolute position detecting means is abnormal, when the moving body passes near the branch point of the route, it is detected by the absolute position detecting means. The equalization process is performed to determine the current position of the moving body by equalizing the weights of the detection result of the displacement detection means and the detection result of the displacement detection means. If the detected absolute position, which is the detection result of the absolute position detection means, is determined to be abnormal, it may be significantly different from the actual current position, and it is abnormal when the moving body passes near the branch point of the route. Even if the current position of the moving body is determined by weighting so as to increase the weight of the detected absolute position determined to be different from the actual current position. When the moving body passes near the branch point, the accuracy of detection of the moving amount of the moving body by the displacement detecting means is lower than when the moving body passes other than near the branch point. Is sufficiently close to the actual current position as compared with the detected absolute position determined to be abnormal. Therefore, when it is determined that the detection result of the absolute position detection means is abnormal, when the moving body passes near the branch point of the route, the detection result of the absolute position detection means and the detection result of the displacement detection means By equalizing the weights of
The influence of the detected absolute position on the determination of the current position can be reduced to prevent the determined current position from deviating from the actual current position as much as possible.

According to the third aspect of the invention, when the absolute position cannot be detected by the absolute position detecting means, the position determining means determines the current position of the moving body based only on the movement amount detected by the displacement detecting means. A feature is that a movement amount emphasis process for determining a position is performed.

According to the third aspect of the present invention, when the absolute position cannot be detected by the absolute position detecting means, the movement amount emphasis process for determining the current position of the moving body based on only the detected movement amount is performed. Be seen. When the absolute position cannot be detected by the absolute position detecting means, the detection result detected by the absolute position detecting means cannot be used when the moving body passes near the branch point of the route. By determining the current position based only on the detection result, it is possible to prevent the determined current position from deviating largely from the actual current position.

According to a fourth aspect of the present invention, the absolute position-oriented processing determines an evaluation value of the detected absolute position with respect to a plurality of current position candidates set based on the detected absolute position and the detected movement amount. A candidate evaluation value is obtained based on a value multiplied by a weighting coefficient that increases the weight of the detected absolute position and an evaluation value of the detected movement amount, and each candidate is detected every time the detected absolute position and the detected movement amount are detected. Accumulate evaluation values,
It is characterized in that it includes a process of determining the candidate having the largest accumulated evaluation value as the current position of the moving body.

According to the fourth aspect of the present invention, in the absolute position emphasis process, the evaluation value of the detected absolute position is set for the plurality of current position candidates set based on the detected absolute position and the detected movement amount. A candidate evaluation value is obtained based on a value multiplied by a weighting coefficient that increases the weight of the detected absolute position and an evaluation value of the detected movement amount, and each candidate is detected every time the detected absolute position and the detected movement amount are detected. A process of accumulating the evaluation values and determining the candidate having the largest accumulated evaluation value as the current position of the mobile body is included. Since the candidate evaluation value is weighted so that the weight of the detected absolute position detected by the absolute position detection means becomes large, when the moving body passes near the branch point, it has a low accuracy for determining the current position. The influence of the detected movement amount is small. Further, for each candidate, the candidate evaluation value is accumulated every time the detected absolute position and the detected movement amount are detected, and the candidate having the largest accumulated candidate evaluation value among the candidates is determined as the current position of the moving body. Therefore, the determined current position can be brought as close as possible to the actual current position.

According to a fifth aspect of the present invention, the absolute position emphasizing process is set by the detected movement amount from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. When the candidate is determined to be the current position, the candidate close to the detected absolute position includes a process of changing the current position.

According to the fifth aspect of the present invention, in the absolute position emphasis process, a candidate set by the detected movement amount is selected from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. Is determined to be the current position,
The candidate close to the detected absolute position includes a process of changing the current position. If the candidate set by the detected movement amount is determined at the current position when the moving body passes near the branch point, this candidate is set by the low-precision detected movement amount. Even if the current position of the moving body is determined based on the detected moving amount, it may be different from the actual current position. Therefore, when the moving object passes near the branch point, even if the candidate set by the detected movement amount is determined to be the current position, the current position is changed by changing the current position to a candidate close to the detected absolute position. The influence of the low-precision detected movement amount on the determination is reduced, and the determined current position can be brought as close as possible to the actual current position.

According to a sixth aspect of the present invention, the absolute position emphasis process includes a process of determining the current position based only on the absolute position detected by the absolute position detecting means.

According to the sixth aspect of the present invention, the absolute position emphasis process includes a process of determining the current position based only on the detected absolute position. Therefore, when the moving body passes near the branch point, It is possible to completely eliminate the influence of the low-precision detected movement amount on the determination of the current position, and to make the determined current position as close as possible to the actual current position.

According to a seventh aspect of the present invention, based on the route information of the route database means, the current route in which the current position of the moving body is present is branched into a plurality of selected routes ahead of the moving direction of the moving body. In the case of, the branch determination means for determining whether the angle formed by each selected path at the branch point is less than or equal to a predetermined set angle, the position determining means, the angle formed by each selected path at the branch point is If the angle is less than or equal to the set angle, the absolute position priority process is performed when the moving body passes through this branch point, and if the angle formed by each selected route at the branch point exceeds the set angle, the moving body passes through this branch point. In this case, the equalization processing for determining the current position of the moving body by equalizing the weights of the detection result detected by the absolute position detection means and the detection result of the displacement detection means is performed. That.

According to the invention of claim 7, when the angle formed by each selected route at the branch point is equal to or less than the set angle,
When the moving body passes through this branch point, the absolute position-oriented processing is performed. When the moving body passes near the branch point where the angle formed by each selected route at the branch point is less than or equal to the set angle, the accuracy of detection of the moving amount of the moving body by the displacement detection means is not near the branch point. However, even if the current position of the moving body is determined on the basis of the detected movement amount with such extremely low accuracy, the actual position will be extremely low compared to the case where the actual position is detected. It is very different from the current position. Therefore, when the moving body passes near such a branch point, weighting is performed so that the weight of the detected absolute position detected by the absolute position detection means becomes large, so that the detection of the current position with extremely low accuracy is performed. The influence of the movement amount can be reduced, and the determined current position can be brought as close as possible to the actual current position.

When the angle formed by each of the selected paths at the branch point exceeds the set angle, the detection result detected by the absolute position detection means and the detection result of the displacement detection means when the moving body passes through the branch point. The equalization process is performed to determine the current position of the moving body by equalizing the weights of. When the moving body passes near the branch point such that the angle formed by each selected route at the branch point exceeds the set angle, the displacement detection means detects the moving amount of the moving body at a precision other than near the branch point. Since it does not change much compared with the case, the current position is determined to be close to the actual current position based on the detected movement amount. Therefore, when the moving body passes near such a branch point, the current position determined by the absolute position detection means and the detection result of the displacement detection means are set to be equal in weight so that the determined current position is almost equal. It can be the actual current position.

The invention according to claim 8 is characterized in that the position determining means cancels the absolute position emphasis process when a predetermined cancellation condition is satisfied during the absolute position emphasis process.

According to the eighth aspect of the present invention, the absolute position emphasis process is canceled when a predetermined cancellation condition is satisfied during the absolute position emphasis process. The absolute position-oriented processing is performed when the moving body passes near the branch point, and the accuracy of detection of the moving amount of the moving body by the displacement detecting means becomes extremely low as compared with when the moving body passes other than near the branch point. Alternatively, it is performed when the detection accuracy is extremely lower than the detection accuracy of the absolute position detection means, but the release condition is set such that the detection accuracy of the movement amount of the moving body by the displacement detection means is better than the detection accuracy of the absolute position detection means. If certain conditions are set, when the absolute position emphasis process is cancelled, it is possible to determine a current position that is much closer to the actual current position than the current position of the moving body determined by the absolute position emphasis process. it can.

Further, if the current position is continuously determined without canceling the absolute position emphasis process, even if the detection accuracy of the absolute position detection means becomes lower than the detection accuracy of the displacement detection means,
When the current position of the moving body, which is determined based on the detected absolute position with low accuracy, is determined, the current position determined in this way greatly differs from the actual current position. By canceling the absolute position emphasis process when the predetermined cancellation condition is satisfied, it is possible to reliably prevent the current position thus determined from being significantly different from the actual current position.

According to the invention of claim 9, the cancellation condition is
It is characterized by including a moving distance condition that the moving distance from the branch point reaches a predetermined set distance after passing the branch point.

According to the ninth aspect of the invention, the releasing condition includes a moving distance condition that the moving distance from the branch point reaches a predetermined set distance after passing the branch point.
After the moving body has passed the branch point, when the moving distance from the branch point reaches a predetermined set distance, the accuracy of detection of the moving amount of the moving body by the displacement detecting means is at least when the moving body passes near the branch point. Good compared to accuracy. Therefore, when the absolute position-oriented process is canceled, it is possible to determine a current position that is much closer to the actual current position than the current position of the moving body determined by the absolute position-oriented process.

According to a tenth aspect of the present invention, the cancellation condition is a candidate for the current position which is set based on the absolute position detected by the absolute position detection means and the movement amount detected by the displacement detection means after passing the branch point. Is included in the candidate single condition.

According to the tenth aspect of the invention, the cancel condition is that the candidate for the current position set based on the detected absolute position and the detected movement amount becomes one after the passage of the branch point. A single condition is included. If there is only one candidate for the current position, this candidate itself is very close to the actual current position, so if such a current position very close to the actual current position is determined. By canceling the absolute position important process and determining the current position of the moving body based on the detected absolute position and the detected movement amount, the current position of the moving body after passing the branch point can be determined to be almost the actual current position. Can be

According to a tenth aspect of the present invention, in the case where the cancellation condition is that the candidate set by the displacement detected by the displacement detecting means is determined to be the current position after passing the branch point, the absolute position detected is detected. It is characterized in that the candidates close to are including a position change condition that the current position is changed.

According to the eleventh aspect of the present invention, the cancellation condition includes a candidate close to the detected absolute position when the candidate set by the detected movement amount is determined to be the current position after passing the branch point. , A position change condition that the current position is changed is included. When the current position is changed to a candidate close to the detected absolute position in this way, the changed current position is affected by the low-precision detected movement amount by the displacement detection means when the moving body is passing near the branch point. Is small and very close to the actual current position. Therefore, when such a current position very close to the actual current position is determined, the absolute position important process is canceled and the current position of the moving body is determined based on the detected absolute position and the detected movement amount. By doing so, the current position of the moving body after passing the branch point can be made substantially the actual current position.

According to a twelfth aspect of the present invention, in the case where the cancellation condition is such that the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount, a branch is made. The minimum error after passing a point is that the distance between the candidate determined as the current position and the detected absolute position is continuously smaller than the distance between another candidate and the detected absolute position over a predetermined set time. It is characterized by including a time condition.

According to the twelfth aspect of the present invention, the release condition is such that the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. After passing the point, the distance between the candidate determined as the current position and the detected absolute position is continuously smaller than the distance between the other candidate and the detected absolute position for a preset time period. Is included. After passing the branch point, the distance between the candidate determined as the current position and the detected absolute position is smaller than the distance between other candidates and the detected absolute position continuously over a preset time, which means that the current position It can be said that at least the candidates determined to have no influence of the low-precision detected movement amount, in other words, the accuracy of the detected movement amount is good. Therefore, if the distance between the candidate determined as the current position and the detected absolute position after passing the branch point is continuously smaller than the distance between other candidates and the detected absolute position for a preset time, the absolute By canceling the position-important process and determining the current position of the moving body based on the detected absolute position and the detected movement amount, the current position of the moving body after passing the branch point can be made almost the actual current position. it can.

According to a thirteenth aspect of the present invention, in the case where the cancellation condition is that the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount, a branch is made. After passing the point, the distance between the candidate determined as the current position and the detected absolute position is smaller than the distance between the other candidate and the detected absolute position continuously while moving a predetermined set distance. It is characterized by including the error minimum distance condition that

According to the thirteenth aspect of the present invention, the release condition is such that the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. After passing the point, the distance between the candidate determined as the current position and the detected absolute position is smaller than the distance between the other candidates and the detected absolute position continuously while moving a predetermined set distance. The minimum error distance condition is included. After passing the branch point, the distance between the candidate determined as the current position and the detected absolute position is smaller than the distance between other candidates and the detected absolute position continuously over a preset distance. It can be said that at least the candidates determined to have no influence of the low-precision detected movement amount, in other words, the accuracy of the detected movement amount is good. Therefore, if the distance between the candidate determined as the current position and the detected absolute position after passing the branch point is smaller than the distance between other candidates and the detected absolute position continuously over a preset distance, the absolute value is Cancel the position important process,
By determining the current position of the moving body based on the detected absolute position and the detected movement amount, the current position of the moving body after passing the branch point can be made substantially the actual current position.

[0036]

1 is a block diagram showing the configuration of a location device 10 according to an embodiment of the present invention.
The location device 10 is a main device in a car navigation device mounted on a moving body such as an automobile, and determines the current position of the own vehicle. The location device 10 includes an absolute position detection unit 11, a displacement detection unit 12, a route database unit 13, a processing unit 14, a display unit 15, an input unit 16, a system bus 17, and an interface unit 1.
8 is included. Own device means location device 1
Shows a car with zero.

Absolute position detecting section 1 which is an absolute position detecting means
1 includes a GPS receiver 11a and a direction sensor 11b, and detects the absolute position of the own vehicle. GPS receiver 11a
Is a global positioning system (Global Pos) with multiple satellites that orbit the earth and emit radio waves including GPS time.
itioning System; Abbreviation: GPS). GPS
The receiver (hereinafter sometimes simply abbreviated as “GPS”) 11a is a receiving device that receives radio waves from satellites, and the own vehicle based on GPS time information of each satellite included in the received radio waves. And an arithmetic unit for calculating the detected absolute position, which is the absolute position of. The azimuth sensor 11b is realized by, for example, a geomagnetic sensor, and detects the detected absolute azimuth, which is the absolute azimuth of the vehicle, by the earth's geomagnetism.

The displacement detecting section 12 which is a displacement detecting means includes a distance sensor 12a, an angular velocity sensor 12b, and other means for detecting the amount of movement of the vehicle. Distance sensor 1
The reference numeral 2a includes, for example, a pulse generator that generates a vehicle speed pulse based on the rotation of wheels, and an arithmetic device that integrates the vehicle speed obtained from the vehicle speed pulse with respect to time to calculate a detected moving amount that is the moving distance of the vehicle. . Angular velocity sensor 12
b is realized by, for example, a vibration gyro, and the detected rotation moment is integrated with respect to time to calculate a detected relative direction which is a relative direction of the own vehicle.

The road database unit 13 (hereinafter sometimes abbreviated as "DB unit 13") which is a route database means is a CD in which road information which is information of roads which are routes through which automobiles can move is recorded. -ROM (Compact Di
road data disk 30 such as sc Read Only Memory)
The CD-ROM driver 13a, which is detachable, optically reads the road data disk 30 and converts it into an electric signal, and converts the electric signal from the CD-ROM driver 13a into a form that can be processed by the processing unit 14. CD-ROM
And a decoder 13b. Usually, road data disk 3
0 is installed in the CD-ROM driver 13a,
In response to the request from the processing unit 14, the CD-ROM driver 13a reads the information recorded on the road data disk 30, and the read information is sent to the processing unit 14 via the CD-ROM decoder 13b. .

FIG. 2 is a diagram schematically showing the nodes and links included in the road information recorded on the road data disk 30. In the road information, a road is represented by nodes that are points on the road and linear links that connect the nodes. For example, in FIG. 2, the road consists of five nodes N1, N2, N3, N4, N5 and four links L1, L2, L3, L4. First node N
1 and the second node N2 are connected by the first link L1, and the second node N2 and the third node N3 are connected by the second link L2. The third node N3 is connected to the fourth node N4 by the third link L3 and is connected to the fifth node N5 by the fourth link L4.

In the road information, as shown in Table 1, at least node position coordinates and links to be connected are set for each node. The node position coordinates are, for example, the latitude and longitude of the node. Further, the node position coordinates may be relative coordinates with respect to a predetermined reference position.

[0042]

[Table 1]

In the road information, as shown in Table 2, at least the link length and the connected node are set for each link. The lengths of the links may be the same or different from each other, but it is desirable to set them so that they are not too long.

[0044]

[Table 2]

When the processing section 14 which is the position determining means, the detection result determining means and the branch determining means functions as the position determining means, at least the absolute position detected by the absolute position detecting section 11 and the movement amount detected by the displacement detecting section 12 are detected. Based on either one and the road information of the DB unit 13,
The current position of the own vehicle is determined in association with the road. Processing unit 1
A central processing unit (abbreviation: CPU) 14a and a read-only memory (Read Only) 4 are provided.
y Memory; abbreviated: ROM) 14b and random access memory (Random Access Memory; abbreviated: RAM) 14
Including c. The CPU 14a centrally controls the location device 10 and performs various processes. ROM14
b is a non-volatile memory that stores programs and the like necessary for the CPU 14a to perform processing. RAM14c
Is a volatile memory that temporarily stores various data including road information and detected absolute position and detected movement amount handled during processing by the CPU 14a.

The display unit 15 includes a graphic controller 15a, a graphic memory 15b, a display controller 15c and a display device 15d. The graphic controller 15a stores the processing result from the processing unit 14 in the graphic memory 15b and gives the processing result stored in the graphic memory 15b to the display controller 15c. The display controller 15c controls the display device 15d. The display device 15d is, for example, a liquid crystal display (Liquid Crystal Display; abbreviation: LC).
It is realized in D) and displays the processing result from the processing unit 14.

In a vehicle equipped with the location device 10, a first switch 20a for switching supply and stop of electric current to a lamp which is turned on during night driving, and a current to a regulator 21 which controls the vehicle equipment lamp which is turned on during night driving. A switch detection circuit 22 for detecting the switching state with the second switch 20b for switching the supply and stop of the power supply is provided.
The switching state detected by the switch detection circuit 22 is given to the processing unit 14, and the processing unit 14 controls the brightness of the backlight of the display device 15d via the display controller 15c based on the switching state.

The input device 16 is realized by buttons and a touch panel, for example, and is operated by the operator of the location device 10 to input various commands. The system bus 17 includes a road database unit 13, a processing unit 14, a display unit 15, an input device 16, and an interface unit 18.
Are electrically connected to each other. Interface section 18
Are GPS 11a, direction sensor 11b, distance sensor 12
a and the angular velocity sensor 12b are electrically connected to the system bus 17.

FIG. 3 is a schematic diagram for explaining map matching when an automobile passes a branch point. Map matching means that the processing unit 14 functions as a position determining means based on the detected movement amount and the detected relative direction of the own vehicle mainly by the displacement detection unit 12 and the road information of the DB unit 13, and The current position is determined in association with the road. The detected absolute position and detected absolute azimuth of the absolute position detection unit 11 in map matching are used to correct the current position of the own vehicle determined based on the detected movement amount, and at predetermined time intervals and predetermined movement amounts. Referred to.

Referring to FIGS. 2 and 3 (1), the vehicle C
A first method of map matching when 1 passes through the third node N3 which is a branch point will be described. The processing unit 14
Based on the road information of the DB unit 13, the second link L2, which is the current road where the current position of the own vehicle C1 exists, is the own vehicle C1.
It is determined that the third node N3 ahead of the moving direction of (3) is branched to the plurality of selected roads, that is, the third link L3 and the fourth link L4.

Subsequently, the processing unit 14 sets the movement vector v3 at the third node N3 based on the relative azimuth detected by the displacement detection unit 12 when the vehicle C1 passes through the third node N3. Then, the processing unit 14 includes the displacement detection unit 1
Based on the detected movement amount of the own vehicle C1 by 2, the candidate a1 is set on the third link L3 and the candidate a2 is set on the fourth link L4 as candidates for the current position of the own vehicle C1. At this time, the processing unit 14 controls any one of the plurality of current position candidates as the current position and controls the display unit 15 to display the current position and the map together.

Subsequently, the processing unit 14 moves all the candidates a1 and a2 of the current position based on the detected movement amount of the own vehicle C1 by the displacement detection unit 12. When the detected movement amount from the third node N3 reaches a predetermined movement amount, the processing unit 14
The distance p1 between the movement vector v3 and the candidate a1 on the third link L3 is compared with the distance p2 between the movement vector v3 and the candidate a2 on the fourth link L4, and the distance from the movement vector v3 is the shortest. The first candidate is the current position
After determining the candidates, the remaining candidates are left as the second candidates. Further, at this time, the processing unit 14 discards the candidates whose distance from the movement vector v3 is a predetermined distance or more.

Referring to FIGS. 2 and 3 (2), the vehicle C
A second method of map matching when 1 passes through the third node N3 which is a branch point will be described. The processing unit 14
Based on the road information of the DB unit 13, the second link L2, which is the current road where the current position of the own vehicle C1 exists, is the own vehicle C1.
It is determined that the third node N3 ahead of the moving direction of (3) is branched to the plurality of selected roads, that is, the third link L3 and the fourth link L4.

Subsequently, when the vehicle C1 passes through the third node N3, the processing unit 14 sets the movement vector v3 at the third node N3 based on the relative azimuth detected by the displacement detecting unit 12. Then, the processing unit 14 includes the displacement detection unit 1
Based on the detected movement amount of the own vehicle C1 by 2, the candidate a1 is set on the third link L3 and the candidate a2 is set on the fourth link L4 as candidates for the current position of the own vehicle C1. At this time, the processing unit 14 controls any one of the plurality of current position candidates as the current position and controls the display unit 15 to display the current position and the map together.

Subsequently, the processing unit 14 moves all the candidates a1 and a2 of the current position based on the detected moving amount of the own vehicle C1 by the displacement detecting unit 12. When the detected movement amount from the third node N3 reaches a predetermined movement amount, the processing unit 14
Third link L3 in which movement vector v3 and candidate a1 exist
The angle θ1 formed by and the angle θ2 formed by the movement vector v3 and the fourth link L4 in which the candidate a2 exists are compared,
The candidate on the link that forms the smallest angle with the movement vector v3 is determined as the first candidate, which is the current position, and the remaining candidates are left as second candidates. Further, at this time, the processing unit 14 discards the candidates existing on the link whose angle formed by the movement vector v3 is equal to or larger than the predetermined angle.

According to at least one of the above two methods, the current position of the own vehicle is determined by performing map matching of the current position of the own vehicle after passing the branch.

FIG. 4 is a flow chart showing the procedure of processing when an automobile equipped with the location device 10 passes near a road branch. The procedure is started in step s0 and proceeds to step s1. In step s1, the processing unit 14 of the location device 10 determines, based on the road information from the DB unit 13, that the node that is about to pass is
Except for the passed link, whether two or more links are connected, that is, whether the road on which the current position of the vehicle exists is branched to a plurality of selected roads ahead of the moving direction of the vehicle. If it is determined that the branch is made, the process proceeds to step s1, and if it is not branched, the process proceeds to step s8.

When it is determined in step s1 that the road on which the current position of the vehicle is present branches into a plurality of roads ahead of the vehicle in the moving direction, the process proceeds to step s2.
Then, the processing unit 14 functions as a branch determination unit, and the DB
Based on the road information from the section 13, it is determined whether the angle formed by each selected road at the branch point is equal to or less than a predetermined set angle, that is, whether the branch is a narrow angle branch, and the narrow angle branch is performed. If it is determined that
If it is determined that the branch is not a narrow angle branch, the process proceeds to step a8. In step s2, the predetermined set angle is set to about 15 to 20 degrees when a vibration gyro is used as the angular velocity sensor 12b, for example, a measurement error is likely to occur in the detection result of the angular velocity sensor 12b of the displacement detector 12. Is set. The angle formed by each selected road at the branch point may be included in the road information or may be obtained from the coordinates of the nodes connected by the link.

When it is determined in step s2 that the branch is a narrow angle branch and the process proceeds to step s3, in step s3, the processing unit 1
4 determines whether or not the absolute position of the own vehicle can be detected by the absolute position detection unit 11. When it is determined that the absolute position can be detected, the process proceeds to step s4, and when it is determined that the absolute position is not detected, the process proceeds to step s9. move on.

In step s3, it is determined that the absolute position can be detected by the absolute position detecting unit 11, and the step s4 is executed.
In step s4, the processing unit 14 functions as a detection result determining unit to determine whether the detection result of the absolute position detection unit 11 is normal or abnormal. The process proceeds to s5, and if it is determined that the abnormality is detected, the process proceeds to step s8.

FIG. 5 is a diagram schematically showing an example of a method for determining whether the detection result of the absolute position detection unit 11 in step s4 of the flowchart of FIG. 4 is normal or abnormal. The GPS 11a calculates the absolute position of the own vehicle based on the GPS time included in the radio waves from the satellites. For example, when the automobile is moving in a high-rise building street, the radio waves from the satellites are reflected by an object such as a high-rise building. Then, a phenomenon generally called multipath occurs such that the GPS 11a is reached. When such a multipath occurs, the radio waves from the satellite received by the GPS 11a will be transmitted from the satellite by GP compared to the signal when the multipath does not occur.
The total distance of the route to reach S11a becomes long, and the distance between the satellite and the own vehicle cannot be accurately measured, which causes the detection result of the absolute position detection unit 11 to be abnormal.

Absolute position detector 1 in such a case
As an example of a method of determining whether the detection result of No. 1 is normal or abnormal, a method of comparing the locus of the detected absolute position of the absolute position detection unit 11 and the locus of the detected relative azimuth of the displacement detection unit 12 is described. To use. Reference numeral va in FIG. 5 is a locus of a relative direction of detection of the own vehicle by the angular velocity sensor 12b of the displacement detection unit 12, and arrows u1 and u2 are loci of absolute positions of the own vehicle detected by the absolute position detection unit 11. .

When the locus of the detected absolute position is a locus like arrow u1, the locus u1 of the detected absolute position is indicated by arrow v.
Since it is similar to the locus of the detected relative azimuth shown in a,
The processing unit 14 determines that the detection result of the absolute position detection unit 11 is normal. When the locus of the detected absolute position is a locus like arrow u2, the locus u2 of the detected absolute position
Is not similar to the locus of the detected relative azimuth indicated by the arrow va, the processing unit 14 determines that the detection result of the absolute position detection unit 11 is abnormal.

The arrangement of a plurality of satellites with respect to the own vehicle may affect the detection result of the absolute position detector 11. For example, when there are three satellites transmitting radio waves that the GPS 11a can receive, these three satellites are
If all of them are in the same direction with respect to the own vehicle, even if the absolute position of the own vehicle is detected based on the GPS time included in the radio waves from these three satellites, only the detection position with low accuracy can be obtained. .

Absolute position detector 1 in such a case
As an example of a method for determining whether the detection result of No. 1 is normal or abnormal, the horizontal accuracy decrease rate (Horizontal Dil) indicating the decrease rate of the positioning accuracy in horizontal two-dimensional positioning is shown.
ution Of Precision (abbreviation: HDOP) and the position accuracy decrease rate (Posi) that indicates the decrease rate of positioning accuracy in three-dimensional positioning.
Calculation Dilution Of Precision (abbreviation: PDOP), and when these values are smaller than a predetermined value,
It is determined that the detection result of the absolute position detection unit 11 is normal,
When these values exceed the predetermined values, it is determined that the detection result of the absolute position detector 11 is abnormal.

When it is determined in step s4 that the detection result of the absolute position detector 11 is normal and the process proceeds to step s5,
In step s5, the processing unit 14 performs an absolute position-oriented process of weighting the detected absolute position so that the detected absolute position is weighted and determining the current position of the vehicle, and then proceeds to step s6.
The absolute position-oriented processing will be described later.

In step s6, the processing unit 14 determines whether or not the predetermined release condition is satisfied based on the detected absolute position, the detected movement amount, the current position candidate, and the like, and determines that the condition is satisfied. The process proceeds to step s7, and if it is determined that the condition is not satisfied, the process returns to step s5. The predetermined release condition will be described later.

When it is determined in step s6 that the predetermined release condition is satisfied and the process proceeds to step s7, the processing section 14 releases the absolute position emphasis process and returns to step s1 in step s7.

When it is determined in step s1 that the road on which the current position of the vehicle is present does not branch into a plurality of roads ahead of the vehicle in the moving direction, it is determined in step s2 that the road is not a narrow-angle branch. If, and if it is determined in step s4 that the detection result of the absolute position detection unit 11 is abnormal, the process proceeds to step s8, and in step s8, the processing unit 1
In step 4, the equalizing process is performed, and the process returns to step s1. The equalization process will be described later.

In step s3, it is determined that the absolute position cannot be detected by the absolute position detector 11, and the step s
In step s9, the processing unit 14 performs the movement amount emphasis process and returns to step s1. The movement amount emphasis process will be described later.

FIG. 6 is a diagram for explaining the weights in the absolute position emphasis process of step s5 and the equalization process of step s8 in the flowchart of FIG. It is assumed that the own vehicle is moving on the link Le. The distance between the absolute position P _GPS detected by the absolute position detector 11 and the link Le is L _GPS . Further, the distance between the detected relative position Pr based on the movement amount detected by the displacement detection unit 11 and the link Le is set to L, and the movement vector V1 based on the relative direction detected by the displacement detection unit 11 is set.
The angle formed by and the link Le is θ. At this time, if the candidate of the current position of the vehicle on the link Le determined by the map matching is A1, then the candidate evaluation value V of the candidate is calculated.
a is defined by the following equation (1). Va = F (θ, L)
-KL _GPS (1)

F (θ, L) of the first term on the right side of the above equation (1)
Is an evaluation value based on the detected movement amount and the detected relative azimuth. The smaller the angle θ formed by the movement vector V1 based on the detected relative azimuth and the link Le, the larger the evaluation value F (θ, L) based on the detected movement amount, and the detected relative position based on the movement amount detected by the displacement detection unit 11. The smaller the distance L between Pr and the link Le, the larger the value. K in the second term on the right side of the above equation (1) is a weighting coefficient. Further, L _GPS , which is the distance between the detected absolute position P _GPS and the link Le, which is the second term on the right side of the above equation (1), is used as the evaluation value of the detected absolute position.

In the absolute position emphasizing process in step s5 of the flowchart of FIG. 4, the evaluation value L _GPS of the detected absolute position is set so that the weight of the detected absolute position P _GPS becomes large.
The value K · L _GPS multiplied by a weighting coefficient K, is subtracted from the evaluation value F based on the detected movement amount and the detected relative direction (θ, L), and the candidate evaluation value Va of the candidate A1 of the current position of the vehicle in . Further, the candidate evaluation value Va is calculated for each candidate each time the detected absolute position and the detected relative position are detected, and is accumulated for each candidate. The candidate evaluation values accumulated for each candidate are compared, and the candidate having the largest accumulated candidate evaluation value is set as the current position of the vehicle. At this time, the weight coefficient K is set to a value exceeding 1. The accumulation of the candidate evaluation values Va is performed, for example, by adding the candidate evaluation values Va or arithmetically averaging the candidate evaluation values Va each time the detected absolute position and the detected relative position are detected.

As described above, according to the location device 10 of the present embodiment, the vehicle passes near the branch point of the road, especially near the branch point where the angle formed by each selected route at the branch point is equal to or less than the set angle. In doing so, weighting is performed so that the weight of the detected absolute position detected by the absolute position detection unit 11 becomes large, and at least based on the detected absolute position weighted in this way and the route information of the DB unit 13. , Absolute position-oriented processing for determining the current position of the own vehicle in association with the road is performed. When the own vehicle passes near the branch point, the accuracy of detection of the amount of movement and the relative azimuth of the own vehicle by the displacement detection unit 12 becomes lower than that when the own vehicle passes other than near the branch point, or the absolute position detection unit 11 However, even if the current position of the vehicle is determined based on the detected movement amount and the detected relative azimuth with such low accuracy, it may differ from the actual current position. Therefore, when the own vehicle passes near the branch point, the absolute position detection unit 1
By weighting the detected absolute position detected by 1 so as to have a large weight, the influence of the low-precision detected movement amount and the detected relative azimuth on the determination of the current position is reduced, and the determined current position is actually determined. You can get as close as possible to your current position.

Further, the location device 10 of the present embodiment
According to the absolute position-oriented process, according to the detected movement amount, the detected relative azimuth, and the plurality of current position candidates set based on the detected absolute position, the detected absolute position evaluation value L _GPS is _assigned to the detected absolute position weight. Is multiplied by a weighting coefficient K and an evaluation value F (θ, L) based on the detected movement amount and the detected relative azimuth to obtain a candidate evaluation value Va, and the detected movement amount, the detected relative azimuth, and the detected absolute position are obtained. Each time the is detected, each candidate evaluation value is accumulated, and the candidate having the largest accumulated evaluation value is determined as the current position of the vehicle. Since the candidate evaluation value Va is weighted so that the weight of the detected absolute position detected by the absolute position detection unit 11 is large, when the vehicle passes through the vicinity of the branch point, the candidate evaluation value Va is low compared with the determination of the current position. The influence of the detected movement amount and the detected relative displacement of accuracy is small. Furthermore, for each candidate, the candidate evaluation value is accumulated each time the detected movement amount, the detected relative azimuth, and the detected absolute position are detected,
Since the candidate having the largest accumulated candidate evaluation value among the candidates is determined as the current position of the vehicle, the determined current position can be brought as close as possible to the actual current position.

FIG. 7 is a diagram for explaining the process of changing the current position included in the absolute position-oriented process. Absolute position emphasis processing is performed when the candidate set by the detected movement amount is determined to be the current position from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. The candidates close to may include a process of changing the current position. As shown in FIG. 7, after the own vehicle has passed the branch point N3, the candidate bs of the current position set by the detected relative position Ps of the own vehicle based on the movement amount detected by the displacement detection unit 12, and the absolute position detection unit. There is a candidate bq of the current position set by the detected absolute position Pq by 11, and the candidate bs of the current position set by the detected relative position Ps among these candidates bs, bq is determined as the current position. In such a case, in the absolute position emphasis process, the current position is changed so that the current position candidate bq set by the detected absolute position Pq is determined as the current position.

As described above, according to the location device 10 of the present embodiment, in the absolute position-oriented processing, the detected movement amount is selected from a plurality of current position candidates set based on the detected absolute position and the detected movement amount. When the candidate set by is determined to be the current position, the candidate close to the detected absolute position includes a process of changing the current position. If the candidate set by the detected movement amount is determined to be the current position when the vehicle passes near the branch point, this candidate is
Since it is set by the low-accuracy detected movement amount, even if the current position of the host vehicle is determined based on such detected movement amount, it may differ from the actual current position. Therefore, when the vehicle passes near the branch point, even if the candidate set by the detected movement amount is determined to be the current position, the current position is changed by changing the current position to a candidate close to the detected absolute position. The influence of the low-precision detected movement amount on the determination is reduced, and the determined current position can be brought as close as possible to the actual current position.

Further, the absolute position emphasis process may include a process of determining the current position based on only the detected absolute position. As a result, when the own vehicle passes near the branch point, the influence of the low-precision detected movement amount on the determination of the current position can be eliminated, and the determined current position can be made as close as possible to the actual current position. .

In the equalizing process in step s8 of the flowchart of FIG. 4, the detection result detected by the absolute position detection unit 11 and the detection result of the displacement detection unit 12 are weighted to determine the current position of the vehicle. Processing. That is, this is the processing when the weighting coefficient K is set to 1 in the above equation (1). This equalization process is mainly performed when the vehicle is moving on the road except for the branch point, and when it is determined that the vehicle is not the narrow angle branch in step s2 in the flowchart of FIG. 4, and the absolute position detection unit in step s4. It is also performed when it is determined that the detection result of 11 is abnormal.

For example, when the own vehicle is moving below the viaduct, the GPS 11a cannot receive the radio waves from the required number of satellites to accurately detect the absolute position of the own vehicle, and thus the own vehicle The absolute position of cannot be detected accurately.
Further, for example, when the own vehicle is moving in the vicinity of the DC electrification railroad, the magnetic field generated by the direct current flowing through the overhead wire of the DC electrification railroad is present in the automobile, so that the body of the automobile becomes magnetized. Direction sensor 11b
Confuses the magnetism on the vehicle body with the geomagnetism, and cannot accurately detect the absolute direction of the vehicle.

In such cases, it is determined in step s4 that the detection result of the absolute position detector 11 is abnormal. In this way, when it is determined that the detected absolute position and the detected absolute azimuth, which are the detection results of the absolute position detection unit 11, are abnormal, the actual current position may differ greatly,
Even when the current position of the host vehicle is determined by weighting it so that the weight of the detected absolute position determined to be abnormal is increased when the host vehicle passes near the road junction, Is different. When the own vehicle passes near the branch point, the accuracy of detection of the amount of movement and the relative azimuth of the own vehicle by the displacement detection unit 12 becomes lower than when the vehicle passes other than near the branch point. The low detected movement amount and the detected relative azimuth are sufficiently close to the actual current position as compared with the detected absolute position and the detected absolute azimuth determined to be abnormal.
Therefore, when it is determined that the detection result of the absolute position detection unit 11 is abnormal, the detection result detected by the absolute position detection unit 11 and the detection of the displacement detection unit 12 when the vehicle passes near the branch point of the route. By equalizing the weight with the result, it is possible to reduce the influence of the detected absolute position and the detected absolute azimuth on the determination of the current position, and to deviate the determined current position from the actual current position as much as possible. Can be prevented.

Further, step s2 in the flowchart of FIG.
When it is determined that the angle formed by each selected road at the branch point exceeds the set angle, the detection result detected by the absolute position detection section 11 and the detection by the displacement detection section 12 when the vehicle passes through this branch point. Equal processing is performed to determine the current position of the own vehicle by equalizing the weight with the result. My car is
When passing the vicinity of the branch point where the angle formed by each selected road at the branch point exceeds the set angle, the displacement detection unit 12 detects the amount of movement of the own vehicle and the relative azimuth accuracy other than near the branch point. Since it does not change much compared with time, the current position is determined to be close to the actual current position based on the detected movement amount and the detected relative azimuth. Therefore, when an automobile passes near such a branch point, the current position determined by equalizing the weights of the detection result detected by the absolute position detection unit 11 and the detection result of the displacement detection unit 12 It can be almost the actual current position.

Further, step s9 in the flow chart of FIG.
The movement amount emphasis process in is a process when the weighting coefficient K is set to 0 in the above equation (1). This movement amount emphasis process is performed when it is determined in step s3 in the flowchart of FIG. 4 that the absolute position and the absolute direction cannot be detected by the absolute position detection unit 11. For example, when your vehicle is moving in a tunnel, GPS1
1a cannot receive the radio wave from the satellite at all,
The absolute position of your vehicle cannot be detected.

In such a case, movement amount emphasis processing is performed to determine the current position of the vehicle based only on the detected movement amount and the detected relative azimuth. With this, by determining the current position based only on the detection result of the displacement detection means, it is possible to prevent the determined current position from deviating significantly from the actual current position.

The cancellation conditions for determining whether or not the predetermined cancellation conditions are satisfied in step s6 of the flowchart of FIG. 4 include moving distance condition, candidate single condition, position changing condition, minimum error time condition and minimum error distance. At least one of the conditions is included.

The moving distance condition is that after the vehicle has passed the branch point,
That is, the moving distance from the branch point reaches a predetermined set distance. After the vehicle has passed the branch point, when the movement distance from the branch point reaches a predetermined set distance, the accuracy of detection of the amount of movement of the vehicle by the displacement detection unit 12 is at least when the vehicle passes near the branch point. Is better than the accuracy of. Therefore, when the absolute position-oriented process is canceled, it is possible to determine the current position that is much closer to the actual current position than the current position of the vehicle determined by the absolute position-oriented process.

The single candidate condition is that, after passing the branch point, there is only one candidate for the current position of the own vehicle which is set based on the detected absolute position and the detected movement amount. The fact that there is only one candidate for the current position of the host vehicle means that this candidate itself is already very close to the actual position of the actual host vehicle. If the position has been determined, the absolute position important process is canceled and the current position of the own vehicle is determined based on the detected absolute position and the detected movement amount to determine the current position of the own vehicle after passing the branch point. The position can be approximately the actual current position.

The position change condition means that after the vehicle has passed the branch point,
When the candidate set by the detected movement amount is determined to be the current position, the candidate close to the detected absolute position,
The current position is to be changed. In this way, when the current position is changed to a candidate close to the detected absolute position, the changed current position is a low-precision detected movement amount of the displacement detection unit 12 when the vehicle is passing near the branch point. The influence is small, and it is very close to the actual position of the actual vehicle. Therefore, when such a current position very close to the actual current position is determined, the absolute position important process is canceled and the current position of the vehicle is determined based on the detected absolute position and the detected movement amount. By doing so, the current position of the vehicle after passing the branch point can be made substantially the actual current position.

The minimum error time condition means that when the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount, the current position is determined after passing the branch point. The distance between the selected candidate and the detected absolute position is smaller than the distance between the other candidate and the detected absolute position continuously over a predetermined set time.
After passing the branch point of the own vehicle, the distance between the candidate determined as the current position of the own vehicle and the detected absolute position is continuously smaller than the distance between the other candidate and the detected absolute position for a predetermined set time. This means that at least the candidate whose current position is determined is not affected by the low-precision detected movement amount, in other words, the detected movement amount has good accuracy. Therefore, if the distance between the candidate determined as the current position and the detected absolute position after the vehicle has passed the branch point is continuously smaller than the distance between other candidates and the detected absolute position for a preset time, Cancels the absolute position important process, and determines the current position of the vehicle based on the detected absolute position and the detected movement amount, so that the current position of the vehicle after passing the branch point becomes almost the actual current position. can do.

The minimum error distance condition means that when the current position is determined from a plurality of current position candidates of the own vehicle which are set based on the detected absolute position and the detected movement amount, the vehicle passes the branch point. After that, the distance between the candidate determined as the current position and the detected absolute position is continuously smaller than the distance between the other candidate and the detected absolute position while moving a predetermined set distance. After the vehicle has passed through the branch point, it means that the distance between the candidate determined as the current position and the detected absolute position is continuously smaller than the distance between other candidates and the detected absolute position over a preset distance. The candidate determined as the current position is at least not affected by the low-precision detected movement amount. In other words, it can be said that the detected movement amount has good accuracy. Therefore, if the distance between the candidate determined as the current position and the detected absolute position after the vehicle has passed the branch point is smaller than the distance between other candidates and the detected absolute position continuously over a preset distance, By canceling the absolute position important process and determining the current position of the vehicle based on the detected absolute position and the detected movement amount,
The current position of the own vehicle after passing the branch point can be made almost the actual current position.

[0091]

As described above, according to the first aspect of the present invention, when the moving body passes near the branch point, the weighting of the detected absolute position detected by the absolute position detection means becomes large. By doing so, the influence of the low-precision detected movement amount on the determination of the current position can be reduced, and the determined current position can be brought as close as possible to the actual current position.

According to the second aspect of the invention, when it is determined that the detection result of the absolute position detecting means is abnormal,
When the moving body passes near the branch point of the route, the weight of the detection result detected by the absolute position detection means and the detection result of the displacement detection means are equalized to influence the detected absolute position on the determination of the current position. Can be reduced to prevent the determined current position from largely deviating from the actual current position.

According to the third aspect of the invention, when the moving body passes near the branch point of the route, the detection result detected by the absolute position detecting means cannot be used. Therefore, the detection result of the displacement detecting means can be used. By determining the current position based on only the above, it is possible to prevent the determined current position from deviating largely from the actual current position.

According to the invention of claim 4, the candidate absolute value and the detected movement amount are detected for each candidate with respect to the candidate evaluation value which is less affected by the low-precision detection movement amount with respect to the determination of the current position. Since the candidate having the largest accumulated candidate evaluation value among the respective candidates is determined as the current position of the moving body, the determined current position can be as close as possible to the actual current position. .

According to the fifth aspect of the invention, when the moving body passes near the branch point, even if the candidate set by the detected movement amount is determined to be the current position, it is close to the detected absolute position. By changing the current position to a candidate,
The influence of the low-precision detected movement amount on the determination of the current position is reduced, and the determined current position can be brought as close as possible to the actual current position.

According to the sixth aspect of the invention, when the moving body passes near the branch point, the influence of the low-precision detected movement amount on the determination of the current position is eliminated, and the determined current position is actually determined. You can get as close as possible to your current position.

According to the invention of claim 7, when the moving body passes near a branch point where the angle formed by each selected route at the branch point is equal to or less than the set angle, it is detected by the absolute position detecting means. By weighting the detected absolute position so that it becomes large, the influence of the extremely low precision detection movement amount on the determination of the current position can be reduced, and the determined current position can be made as close as possible to the actual current position. Can be approached to. When the moving body passes near the branch point where the angle formed by each selected route at the branch point exceeds the set angle, the weight of the detection result detected by the absolute position detection means and the detection result of the displacement detection means Can be made approximately equal to the actual current position.

According to the eighth aspect of the present invention, when the absolute position emphasis process is canceled, the current position which is much closer to the actual current position than the current position of the moving body determined by the absolute position emphasis process is determined. can do.

According to the ninth aspect of the invention, when the absolute position-oriented process is canceled, the current position which is extremely closer to the actual current position than the current position of the moving body determined by the absolute position-oriented process is determined. can do.

According to the tenth aspect of the invention, the fact that there is one candidate for the current position means that this candidate itself is very close to the actual current position. When the current position that is very close to the current position is determined, the absolute position important process is canceled, and the current position of the moving body is determined based on the detected absolute position and the detected movement amount. The current position of the moving body after passing can be made almost the actual current position.

According to the eleventh aspect of the invention, when the current position which is very close to the actual current position is determined, the absolute position important process is canceled and the detected absolute position and the detected movement amount are set. By determining the current position of the moving body based on the above, the current position of the moving body after passing the branch point can be made substantially the actual current position.

According to the twelfth aspect of the invention, after passing through the branch point, the distance between the candidate determined as the current position and the detected absolute position is greater than the distance between other candidates and the detected absolute position in advance. If the moving position is smaller than the set time continuously, the absolute position important process is canceled, and the current position of the moving unit is determined based on the detected absolute position and the detected movement amount. The current position of can be almost the actual current position.

According to the thirteenth aspect of the invention, after passing the branch point, the distance between the candidate determined as the current position and the detected absolute position is greater than the distance between other candidates and the detected absolute position in advance. If the moving object after passing through the branch point is determined by canceling the absolute position important process and determining the current position of the moving object based on the detected absolute position and the detected movement amount when the moving object continues to be small over the set distance. The current position of can be almost the actual current position.

[Brief description of drawings]

FIG. 1 is a location device 10 according to an embodiment of the present invention.
3 is a block diagram showing the configuration of FIG.

FIG. 2 is a diagram schematically showing nodes and links included in road information recorded in a road data disk 30.

FIG. 3 is a schematic diagram for explaining map matching when an automobile passes a branch point.

FIG. 4 is a flowchart showing a procedure of processing when an automobile equipped with the location device 10 passes near a road branch.

5 is a diagram schematically illustrating an example of a method of determining whether the detection result of the absolute position detection unit 11 in step s4 of the flowchart of FIG. 4 is normal or abnormal.

FIG. 6 is a diagram for explaining weights in the absolute position emphasis process of step s5 and the equalization process of step s8 in the flowchart of FIG.

FIG. 7 is a diagram for explaining a process of changing the current position included in the absolute position emphasis process.

[Explanation of symbols]

10 Location device 11 Absolute position detector 12 Displacement detector 13 Road Database Department 14 Processing unit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C032 HB02 HB05 HB22 HB24 HC08                       HC13 HD03 HD29                 2F029 AA02 AB01 AB07 AC02 AC04                       AC14 AD01                 5H180 AA01 BB13 FF04 FF05 FF22                       FF27 FF33

Claims (13)

[Claims] 1. An absolute position detecting means for detecting an absolute position of a moving body, a displacement detecting means for detecting a moving amount of the moving body, and a route database means for storing information on a route along which the moving body can move. In a location device provided, based on at least one of the absolute position detected by the absolute position detection unit and the movement amount detected by the displacement detection unit, and the route information of the route database unit, the current position of the moving body is determined. The position determining means includes a position determining means that determines a position in association with the route, wherein the position determining means weights the detected absolute position so that the weight of the detected absolute position becomes large when the moving body passes near the branch point of the route. A location device characterized by performing an absolute position-oriented process for determining a current position. 2. The method further includes a detection result determination unit that determines whether the detection result of the absolute position detection unit is normal or abnormal, and the position determination unit includes an abnormal detection result of the absolute position detection unit. When it is determined that the moving body passes near the branch point of the route, the detection result detected by the absolute position detecting means and the detection result of the displacement detecting means are set to have the same weight. The location device according to claim 1, wherein an equalizing process for determining the current position is performed. 3. When the absolute position cannot be detected by the absolute position detecting means, the position determining means determines a moving amount based on only the moving amount detected by the displacement detecting means. 3. The location device according to claim 1, wherein the location device performs an emphasis process. 4. The absolute position-oriented processing is performed by assigning a weight of the detected absolute position to an evaluation value of the detected absolute position regarding a plurality of current position candidates set based on the detected absolute position and the detected movement amount. Is multiplied by a weighting coefficient to obtain a candidate evaluation value based on the evaluation value of the detected movement amount, and each candidate evaluation value is accumulated every time the detected absolute position and the detected movement amount are detected. The location device according to any one of claims 1 to 3, further comprising: a process of determining a candidate having the largest accumulated evaluation value as a current position of the moving body. 5. The absolute position emphasis process is performed by selecting a candidate set by the detected movement amount from a plurality of current position candidates set based on the detected absolute position and the detected movement amount as a current position. The location device according to any one of claims 1 to 3, further comprising a process of changing a current position to a candidate close to the detected absolute position when determined. 6. The location according to claim 1, wherein the absolute position emphasis process includes a process of determining a current position based only on an absolute position detected by the absolute position detecting means. apparatus. 7. The current route in which the current position of the mobile body exists is based on the route information of the route database means,
When branching into a plurality of selected routes ahead of the moving direction of the moving body, further includes a branch determination means for determining whether the angle formed by each selected route at the branch point is less than or equal to a predetermined set angle, If the angle formed by each selected route at the branch point is equal to or less than the set angle, the position determining means performs the absolute position emphasis process when the moving body passes through this branch point, and forms the angle formed by each selected route at the branch point. If exceeds the set angle,
When the moving body passes through this branch point, an equalizing process is performed to determine the current position of the moving body by equalizing the weights of the detection result detected by the absolute position detecting means and the detection result of the displacement detecting means. The location device according to any one of claims 1 to 6, characterized in that: 8. The position determining means cancels the absolute position emphasizing process when a predetermined cancellation condition is satisfied during the absolute position emphasizing process.
Location device according to any one of 1. 9. The location device according to claim 8, wherein the release condition includes a moving distance condition that the moving distance from the branch point reaches a predetermined set distance after passing through the branch point. 10. The cancellation condition is that, after passing through a branch point, there is one candidate for the current position set based on the absolute position detected by the absolute position detection means and the movement amount detected by the displacement detection means. Location device according to claim 8 or 9, characterized in that it includes a candidate single condition that is 11. The release condition is that, when a candidate set by the displacement detected by the displacement detecting means is determined to be the current position after passing a branch point, the candidate currently close to the detected absolute position is 11. A position changing condition that the position is changed is included.
Location device according to any one of 1. 12. The canceling condition is such that when the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount, the current position is determined after passing a branch point. The distance between the candidate and the detected absolute position that are determined to include a minimum error time condition that is continuously smaller than the distance between other candidates and the detected absolute position over a predetermined set time. Location device according to any of claims 8 to 11, characterized. 13. The release condition, wherein when the current position is determined from a plurality of current position candidates set based on the detected absolute position and the detected movement amount, the current position is determined after passing a branch point. The minimum error distance condition that the distance between the candidate and the detected absolute position determined to be, is smaller than the distance between the other candidate and the detected absolute position continuously while moving a predetermined set distance. A location device according to any one of claims 8 to 12, comprising: