JPH07104173B2 - Vehicle position detection device - Google Patents

Description

TECHNICAL FIELD The present invention is intended to accurately determine the present position in a vehicle such as an automobile mainly traveling on a road or an autonomous vehicle mainly traveling a predetermined course. The present invention relates to a vehicle position detecting device used for.

2. Description of the Related Art As a method of obtaining the current position of the vehicle in a moving vehicle, there is a method of obtaining the current position as a relative position from the starting point using a distance sensor and a direction sensor, but the error of the sensor accumulates gradually. There is a drawback that the accuracy becomes poor. For this reason, in recent years, a map matching technique has been actively developed in which map data is compared with data obtained during traveling, the estimated position is corrected, and a cumulative error is absorbed to improve accuracy.

As such an apparatus and method, for example, Japanese Patent Application Laid-Open No. 61-5691
There is a vehicle navigation device and method proposed in Japanese Patent Laid-Open No. The block diagram is shown in FIG. 4-a, and the operation explanatory diagram is shown in FIG. 4-b. The information input from the direction sensor 404 and the distance sensor 405 in FIG. 4-a is compared with the road data stored in the map storage medium 402 by the computer 401 to correct the estimated position, which is given from the control console 406. The position of the vehicle is output from the display device 403 together with the map based on the control content. The basics of this method are as follows. The range in which a vehicle may exist spreads on a two-dimensional map due to the accumulation of sensor errors. Considering contours of equal probability that the probability of vehicles existing in two dimensions is equal,
When it intersects with the road center line on the three-dimensional map, it is possible that the vehicle is traveling on that road, and after that, a more detailed determination will be made. This equiprobable contour is the contour 410,41 in FIG.
It becomes larger as you drive normally like 1,412,
It is assumed that there is a possibility that the vehicle runs on the road when the equal probability contour 412 intersects with the road line segment like the road 413. This equi-probability contour is used except when the estimated position of the vehicle is moved to the road by determining that the vehicle is traveling on the road.
It grows larger as you drive. After expanding the equiprobability contour of the current position by repeating these calculations,
By comparing with the road data, it is judged whether or not the estimated position is moved to the road.

In the above-mentioned conventional method, it is good when the vehicle travels in the center of the road, but especially when traveling at the end of a wide road, it is not determined that it is traveling on the road, and the sensor error accumulates. The position detection accuracy sometimes deteriorated. This example is shown in FIG. In this figure, it is assumed that there is a road on the left side where the center line is 201 and the left end of the road is 202 when the vehicle travels to the left on the road, and the vehicle travels on course A from point 203. It is assumed that when the point 204 is reached, the present position existence range (or the current position existence probability contour) due to the accumulated error of the sensor becomes 205. At this time, since the current position existence range 205 includes the road center line 201, it is possible to move to a more detailed determination that the vehicle may be traveling on this road. When traveling on a portion near the end of the road such as the course B, the current position existing range 207 does not include the road center line 201 even if the vehicle reaches the point 206, so it is necessary to judge in consideration of the road width. Become. However, the conventional method does not distinguish between left-hand traffic, right-hand traffic, and one-way traffic, and thus it is not possible to accurately determine a road that may be traveling.

In the conventional method, for example, in a country where a vehicle is traveling on the left side, it is assumed that the vehicle is actually traveling on another road 2 adjacent to the wide road 1 on the right side in the traveling direction of the vehicle. To do. In this case, the right side of the road 1 should not be able to run, but the vehicle may be running on this right side as well.
Since the traveling possibility is determined under the same conditions as the road 2, it is easy to make an error on a road that is traveling with accumulated current position errors, such as when the vehicle turns into the road 2 after traveling a long distance. There was a problem to be solved.

Means for Solving the Problems In order to solve the above problems, the present invention stores a traveling distance detecting means for detecting a traveling distance of a vehicle, a traveling direction detecting means for detecting a traveling direction of a vehicle, and an estimated position of the vehicle. Estimated position stored in the estimated position storage means, the relative distance of the vehicle calculated from the traveling distance detected by the traveling distance detecting means and the traveling direction detected by the traveling direction detecting means. Estimated position calculation means for calculating the estimated position of the vehicle by adding it to the coordinate values of the above and storing it again in the estimated position storage means, the traveling distance obtained from the traveling distance detecting means, and the traveling direction obtained from the traveling direction detecting means. A current position existing range calculating means for calculating the current position existing range from the above, a map storage means for storing road data, data of the position and road width of each road stored therein, left side traffic or Is an effective roadway area of each road that overlaps with the current position existence range calculated by the current position existence range calculation means based on the data for distinguishing the right-way or one-way traffic direction and the travel direction obtained by the travel direction detection means. A road on which the vehicle is traveling is determined from the effective road selecting means for selecting a road and the road selected thereby and the traveling direction obtained from the traveling direction detecting means, and the estimated position storing means is provided on this road. A map matching calculation unit that corrects the stored estimated position and changes the present position existing range, and an output unit that outputs the estimated position stored in the estimated position storage unit are provided.

With the above-described configuration, the present invention obtains an estimated position by integrating the estimated position calculating means from the traveling distance detected by the traveling distance detecting means and the traveling direction detected by the traveling direction detecting means, and the traveling distance and the traveling direction. The present position existence range is obtained from and. On the other hand, the effective road selection means extracts from the map storage means the position of the road, the road width, the information of right-hand traffic or left-hand traffic, whether it is one-way traffic and the data of the traffic direction in that case. A road is selected as a candidate road in which the region of the road that can be traveled in the traveling direction in which the vehicle is traveling overlaps with the current position existing range. The map matching means finds the road on which the vehicle is moving by comparing and comparing the heading and the road direction of the candidate road, and corrects the estimated position on this road, so it travels on a wide road and its vicinity. Even in the case of performing, the position of the vehicle can be accurately obtained.

Embodiment FIG. 1 is a block diagram of an embodiment of the present invention. 101
Is a traveling distance detecting means for detecting the traveling distance of the vehicle by measuring the number of rotations of the wheels. Reference numeral 102 denotes a traveling direction detecting means, which detects the traveling direction of the vehicle using a geomagnetic sensor or the like. 104 is an estimated position storage means for storing the estimated position of the vehicle. 103 is an estimated position calculation means, from the estimated position of the past vehicle stored in the estimated position storage means 104,
A calculation for advancing to the traveling azimuth detected by the traveling azimuth detecting means 102 is performed by the traveling distance detected by the traveling distance detecting means 101, and the result is stored again in the estimated position storage means 104 as an estimated position of a new vehicle. Reference numeral 105 denotes a current position existence range calculation means, which obtains a range in which the current position may exist, for example, as a rectangle from the travel distance, the traveling azimuth, and the estimated position that have been traveled so far. 106 is a map storage means,
The road is approximated by a polygonal line, the road data is stored as coordinate data expressing the polygonal line, and the width of the road and the distinction between left-hand traffic, right-hand traffic, and one-way traffic are also stored. In the case of one-way traffic, directions in which the vehicle can pass are also stored. 107 is an effective roadway selection means, which is an effective roadway in the case of the traveling direction in which the vehicle is currently traveling, based on the data for distinguishing the current traveling direction from the left-hand side traffic, the right-hand side road or one-way (direction that can pass) and the road width data A road whose area overlaps the current position existing range is selected as a candidate road. Reference numeral 108 denotes a map matching calculation means, which determines a road on which the vehicle is traveling from the candidate roads based on the difference between the traveling direction and the road direction, and if it can be determined, corrects the estimated position on this road to determine the present position existence range. To reduce. An output unit 109 outputs the estimated position of the vehicle obtained as described above. This may be a display device that merely displays the estimated position or a display device that displays the estimated position on the map. Further, it may be a line for outputting the estimated position data, an output device for communication, or a voice output device.

FIG. 3 is a diagram for explaining the operation in the above embodiment. In this figure, the initial position of the vehicle is a point 301, and its coordinates are (Xo, Yo). These coordinates are stored in the estimated position storage means 104 and are manually input when the device is installed or set by external information such as radio navigation, but once set, the position where the vehicle stopped last time is set. By storing it, there is no need to reset. The vehicle travels to the point 302, the traveling distance detecting means 101 detects that the vehicle has traveled by D, and the traveling direction detecting means 102 indicates the traveling direction at that time as H.
Then, the estimated position calculation means 103 performs the dead reckoning calculation of X1 = Xo + D.cos (H) Y1 = Yo + D.sin (H) as in the conventional method, and the result is (X1, Y1). Is stored in the estimated position storage means 104. This (X1, Y1) becomes (X
It is assumed that the estimated position of the vehicle has been successively obtained by substituting the values for o, Yo) and repeating the above calculation to reach the estimated position 303.

The accumulated error of the current position estimation due to the error of the sensor increases as the vehicle travels from the starting point, and the current position existing range expands. In the present position existence range calculation means 105,
A rectangle is obtained as the present position existence range, which will be described below.

The coordinates of the starting point 301 are (Xo, Yo), the estimated position 303 from the starting point
Distance from the starting point 301 to the estimated position 303 (Xc, Yc)
When the direction is A to be expressed as L = sqr [(Xc-Xo ) 2 + (Yc-Yo) 2] A = arctan [(Yc-Yo) / (Xc-Xo)]. However, it is necessary to deal with the calculation of arctan so that a result of 0 ° to 360 ° can be obtained. If the expected error of the distance sensor is ed and the expected angle error of the bearing sensor is eh,
The fan shape representing the present position existence range has an azimuth error of ± eh and a distance error of ± L · ed in FIG. When approximating this fan shape as a rectangle that can be easily handled by a computer, the rectangle circumscribing the fan shape is the most suitable current position existence range. From now on, the rectangle circumscribing this fan shape will be treated as the current position existence range. . The size of the front part of the circumscribed rectangle when traveling for a unit length is defined as the front error Ef, and the front, right,
For the left part, backward error Eb, right error Er,
Assuming the left error El, Ef = ed Eb = 1- (1-ed) .cos (eh) Er = (1 + ed) .sin (eh) Er = (1 + ed) .sin (eh). For example, at the point 303, the current position existing range is approximated as a rectangle 304. Let Df be the size of the part in front of the estimated position of this rectangle, and Db, Wr, and Wl for the rear, right, and left parts, respectively. Df = L ・ Ef Db = L ・ Eb Wr = L ・ Er Wl = L · El.

Next, the effective roadway selection means will be described. here,
The selection may be performed on the effective road regions of all roads within a certain distance from the estimated position, but the candidate roads may be narrowed down in advance in order to reduce the calculation time. The method of narrowing down the candidate roads will be described below. First, in order to narrow down candidate roads, consider a rectangle in which all sides are twice the maximum road width than the rectangle of the current position existence range,
A road that includes the center line of the road is selected by clipping. The maximum road width is the width of the widest road in the area, but may be a large constant value (for example, 100 m). Thus, the candidate road segment is selected, and the distance from the estimated position to the center line of each road segment (the road segment number is rd) is set as Dc (rd). Let W (rd) be the road width of road segment rd, and Sr (rd) = 1 when this road is on the left and Sr (rd) =-1 when it is on the right, and Sr (rd) = 0 when it is one-way. Rp (rd) = 1 when the center line of the road segment rd is on the left side with respect to the traveling direction, and Rp (rd) =-1 when it is on the right side. If the proper road width is Wr (rd) and the distance from the estimated position to the proper road is Ds (rd) with a sign, Wr (rd) ＝ W (rd) ・ max (-1, (Sr (rd) ・ Rp (rd))-1) / 2 Ds (rd) = Dc (rd) + Wr (rd) and Lx = sqr (max (Df ² + Wr ² , Df ² + Wl ² , Db ² + Wr ² , Db ² + Wl ² ). For Li = min (Df, Db, Wr, Wl), for each road segment, (1) When Ds (rd)> Lx ... Remove from candidate road.

(2) When Ds (rd) ≤ Li ... Candidate road is determined.

(3) In other cases ... If a straight line that is translated by Wr (rd) from the road center line in the direction of the estimated position is inside the rectangle of the existing position range, it is determined as a candidate road, and if not, it is removed from the candidate road. .

In this way, after determining the candidate road by the effective road selection means,
The next map matching means searches for a road segment to be matched. This is the heading of each candidate road segment and the heading H
The road segment with a certain angle difference of a certain value or more is dropped from the candidate, and the road segment with the shortest distance to the estimated position (Xc, Yc) is selected from the remaining candidate road segments, and the estimated position is changed to this road segment. New estimated position (Xc, Yc) of the coordinate value of the intersection of the dropped down line and the center line of the proper road
Is stored in the estimated position storage means. At the time of this correction,
The current position existing range is reduced so that one side has an appropriate road width. By repeating these steps, the accurate current position is obtained.

The method of matching with the map using the rectangle indicating the current position existence range may be the conventional map matching method cited above.

Effects of the Invention As is apparent from the above embodiments, the present invention compares the roadway region to be traveled and the current position existence range in consideration of the left and right of the road with respect to the traveling direction and one-way traffic, and travels on the road. The vehicle position detection has an excellent effect that the map can be correctly matched even when driving on a wide road or its vicinity, and the position of the vehicle can be accurately determined. The device can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vehicle position detecting device according to an embodiment of the present invention, FIG. 3 is an operation explanatory diagram of the device, FIG. 4a is a configuration diagram of a conventional example, and FIGS. 4b and 2 are It is operation | movement explanatory drawing of a prior art example. 101: traveling distance detecting means, 102: traveling direction detecting means,
103: estimated position calculation means, 104: estimated position storage means,
105: current position existing range calculation means, 106: map storage means, 107: effective roadway selection means, 108: map matching calculation means, 109: output means.

Claims (1)

[Claims] 1. A traveling distance detecting means for detecting a traveling distance of a vehicle, and a traveling direction detecting means for detecting a traveling direction of the vehicle.
Estimated position storage means for storing the estimated position of the vehicle, and a relative movement amount of the vehicle calculated from the traveling distance detected by the traveling distance detection means and the traveling direction detected by the traveling direction detection means to store the estimated position. Estimated position calculation means for calculating the estimated position of the vehicle by adding it to the coordinate value of the estimated position stored in the means and storing it again in the estimated position storage means, the traveling distance and the traveling direction obtained from the traveling distance detecting means. Current position existence range calculation means for calculating the current position existence range from the traveling direction obtained from the detection means, map storage means for storing road data, position data of each road and road width data stored therein. The effective roadway area of each road is calculated by the current position existence range calculation means from the data for distinguishing the left-hand traffic, right-hand traffic, or one-way traffic direction and the travel azimuth obtained by the travel azimuth detection means. Effective road selection means for selecting a road that overlaps with the calculated present position existence range, and a road on which the vehicle is traveling is determined from the selected road and the traveling direction obtained from the traveling direction detecting means. A map matching calculation unit that corrects the estimated position stored in the estimated position storage unit on the road to change the present position existence range, and an output unit that outputs the estimated position stored in the estimated position storage unit A vehicle position detecting device characterized by the above.