JP3404613B2 - Travel locus measuring method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring a traveling locus of a moving body. In particular, it relates to measurement using both the global positioning system and self-contained navigation. More specifically, the present invention relates to a method and a device for correcting a traveling locus of a moving body after the moving body travels.

[0002]

2. Description of the Related Art As a method for detecting the position of a moving body, a global positioning system (hereinafter referred to as "GPS") for detecting an absolute position using radio waves from an artificial satellite is known. GPS is a system that receives radio waves from a plurality of artificial satellites launched to detect the position of a terrestrial mobile body, and performs position detection, so that a vehicle or other mobile body can detect its position. It can be detected as an absolute position represented by latitude and longitude. Further, as a method of detecting a relative position, a self-contained navigation method is known in which a distance sensor and a direction sensor accumulate a movement amount from a reference point to detect a position. Some car navigation devices used in automobiles and the like use both GPS and self-contained navigation, and switch to self-contained navigation in places where GPS cannot be used, such as between buildings and under highways.

[0003]

[Problems to be Solved by the Invention] Not only position detection but also
A car navigation device that switches between GPS and self-contained navigation can also be used to obtain the path traveled by an automobile or the like.

If GPS measurement is possible, the running locus can be obtained by detecting the absolute position in time series.
However, there are cases where the road on which the vehicle has traveled cannot be identified only by GPS. FIG. 4 shows an example of the position detection error by GPS. Even if the stationary position is measured at the measurement position O and the position is detected every one second, the detected position M has a great variation. In the position detection by GPS, the error amount fluctuates in a cycle of several minutes, and the error is about 30 m in standard deviation.

Further, in the self-contained navigation, since the cumulative value of the movement amount is obtained, the error increases in proportion to the measured distance. In the case of automobiles, the rotation of tires is mainly used as a distance sensor for self-contained navigation, and the error varies depending on the road surface condition due to tire air pressure, rain, and the like. The distance error can be reduced by measuring and correcting the distance of one rotation of the tire each time. A gyro is used as a direction sensor for self-contained navigation, but the detection angle error increases in proportion to the bending angle.

FIG. 5 shows an example of the measurement error of the traveling locus by GPS and self-contained navigation. Here, the traveling locus from the traveling start point A to the traveling end point B is shown by a solid line, and the actual traveling locus C along the road is shown by a broken line. The traveling locus detected by GPS has a small error as a whole, but the locus fluctuates depending on the place. On the other hand, in the case of self-contained navigation, there is almost no error in distance, but the error becomes large due to the error in angle.

When GPS and self-contained navigation are switched, respective position detection errors appear, and in a city area or a residential area where roads are densely arranged, it is impossible to directly obtain a correct traveling locus. It is desirable to obtain a travel locus with less position error based on the data obtained by GPS and self-contained navigation.

The present invention solves such a problem, and
It is an object of the present invention to provide a traveling locus measuring method and device capable of obtaining a traveling locus with high positional accuracy by using absolute position data obtained by S and relative position data obtained by self-contained navigation.

[0009]

A method and apparatus for measuring a traveling locus according to the present invention perform absolute position measurement and relative movement amount measurement at the same timing, and obtain a relative traveling locus from relative movement amount data. , Selecting a point at which the moving body is bent at a predetermined angle or more from the relative traveling locus, and for each selected point, the relative measured in time series between that point and the next point The direction of travel and the position of the center of gravity are obtained from the data of the actual movement amount, and the direction of travel and the position of the center of gravity are obtained from the data of the absolute position measured at the same timing as the point selected from the relative traveling trajectory, The relative position of the movement amount data between the two points is adjusted so that the traveling direction and the center-of-gravity position obtained from the movement amount data relative to the obtained moving direction and the center-of-gravity position substantially match. And correcting the relationship.
In order to obtain the traveling direction from the relative movement amount data or the absolute position data, linear approximation is performed by the least square method. Further, the position of the center of gravity is obtained by averaging the positions of the points.

Since the distance data from the distance sensor has few errors, it is effective information for correcting the traveling locus. Further, the direction sensor has a large error when turning at an intersection, but has a small error when traveling on a straight road or a gentle curve. From these facts, the travel locus (element) of the linear portion obtained by self-contained navigation has a small error in the shape of the locus, although the absolute position itself is not correct. Further, the traveling direction read from the traveling locus of GPS has a smaller error than the direction sensor in which a cumulative error occurs. From this, the shape of the element by self-contained navigation and
A traveling locus with less error can be obtained depending on the traveling direction by GPS.

Since the correction is further performed after the correction is performed by the above method, it is possible to display the road and other background maps on the computer screen and manually align the position-corrected elements on the road. Although it may be possible to manually correct the running locus of GPS or self-contained navigation from the beginning, in an area with a narrow road interval such as a residential area, even if you look at the raw running locus, you do not know the road you drove. In many cases, it cannot be corrected. The present invention is also effective when used for preprocessing of manual correction.

[0012]

1 is a diagram showing an embodiment of the present invention, which is a block diagram of a traveling locus measuring device. This travel locus measuring device receives a radio wave from a fixed wireless station or a satellite to measure an absolute position of a moving body represented by latitude and longitude, a GPS receiver 1 and a latitude / longitude detector 2, a distance sensor 3a, The self-contained navigation sensor 3 and the movement amount detector 4, which measure the relative movement amount of the moving body by the direction sensor 3b, and the absolute position data and the relative movement amount data, which are measured in time series, are recorded. It is provided with a recording device 5 and a calculation device 6 for obtaining a traveling locus of a mobile body from data recorded in the recording device 5. GPS
The receiver 1 and the latitude / longitude detector 2, the self-contained navigation sensor 3 and the movement amount detector 4 are set so as to perform measurement at the same timing.

Here, the case of measuring the traveling locus of an automobile will be described as an example. The GPS receiver 1 receives the radio wave from the GPS, and the latitude / longitude detector 2 calculates the latitude / longitude value from the received signal. The self-contained navigation sensor 3 detects the distance and the direction by the distance sensor 3a and the direction sensor 3b, and the movement amount detector 4 calculates the relative movement amount of the vehicle on which this travel locus measuring device is mounted from the detection output. . The recording device 5 records the value of the movement longitude (absolute position data), the relative movement amount (relative position data), and the change angle measured by the direction sensor 3b for each constant distance advance. The arithmetic unit 6 obtains the traveling locus of the automobile from these data. The arithmetic unit 6 may be mounted on an automobile together with other parts, but may have a separable structure so that the data from the recording unit 5 can be read to obtain the traveling locus at a place different from the automobile.

FIG. 2 shows a flow of arithmetic processing for obtaining a traveling locus by the arithmetic unit 6, and FIG. 3 shows an example of a concrete locus. In FIG. 3, (a) is the trajectory of self-contained navigation,
(B) is the GPS trajectory, and (c) is the corrected trajectory.

The computing device 6 first obtains a relative traveling locus from relative movement amount data (relative position data) obtained by self-contained navigation, and the automobile is determined in advance from the relative traveling locus. Select a point that is bent over an angle. This is called a "node point". A line segment between node points is called an "element". For example, the bending angle is 9
If it is 0 degree, it corresponds to a point bent at a right angle at an intersection or the like. If the bending angle is 90 degrees or more, not only the intersection but also the point where the traveling direction changes by 90 degrees or more is selected. In the example of FIG. 3, the node points n1, n2 and n3 are selected and the elements e1, e2, e3 and e4 are obtained. Although the detection of the node point can be easily performed by using the output value of the direction sensor 3b, a person may judge the traveling locus by self-contained navigation by seeing it, and the arithmetic unit 6 can be determined from the point of the traveling locus.
It can also be obtained by In order to obtain it by the computing device 6, for example, an approximate straight line is obtained from a plurality of continuous detection position data, and a point at which the distance from the approximate straight line starts to be a certain value or more is set as a node point.

On the other hand, the points corresponding to the respective node points of the self-contained navigation are obtained from the absolute position data measured by GPS. In the example of FIG. 3, points m1, m2 and m3 are obtained. Since GPS and self-contained navigation measure at the same timing, the corresponding node points can be easily found from the data arrangement.

Next, from the data between the node points of the self-contained navigation (elements e1, e2, e3 in the example of FIG. 3), the barycentric position and the traveling direction of each element are obtained. The traveling direction is the direction obtained by linearly approximating all position data in the element by the least squares method. The barycentric position is the average value of all position data in the element in the X and Y directions. Similarly, for the GPS data, the position of the center of gravity and the traveling direction are obtained.

Relative position correction is performed based on the position of the center of gravity and the traveling direction. That is, the self-contained navigation element is moved to correct the position data so that the traveling direction and the center of gravity position of the element obtained by self-contained navigation match the traveling direction and the center of gravity position of the element obtained by GPS.

The element thus obtained is displayed on the map. An example of the result of correcting the traveling locus of self-contained navigation is shown in FIG.

After that, the trajectory corrected by the relative position correction is displayed against the background of the map such as the road, and the correction is performed manually while comparing with the background road. That is, further correction is performed so that the elements of the locus match the road that seems to have traveled. The fact that the node points at both ends of the element overlap with the node points of the preceding and following elements and that the element must be placed on the road can be used to infer the road on which the vehicle has traveled. The translation and rotation are performed on the inferred road without changing the shape of the element to adapt it.

Then, the finally corrected trajectory is displayed on the map.

[0022]

As described above, the method and apparatus for measuring the traveling locus of the present invention are used in the conventional GPS.
Compared with the method of switching between the self-contained navigation and the self-contained navigation, the traveling locus is corrected by combining the distance information of the self-contained navigation with less error and the direction information of the GPS, so that the position accuracy can be improved. Further, even when the road actually traveled cannot be specified by the travel locus obtained by the method of switching between GPS and self-contained navigation, the correction according to the present invention increases the probability that the road can be specified and allows manual correction. Can be

Furthermore, since conventional devices such as a GPS device and a self-contained navigation device can be used, the position accuracy can be improved without imposing an economical burden on the measuring device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a flow of calculation processing for obtaining a traveling locus.

FIG. 3 is a diagram showing an example of a specific trajectory.

FIG. 4 is a diagram showing an example of a position detection error by GPS.

FIG. 5 is a diagram showing an example of a measurement error of a traveling locus by GPS and self-contained navigation.

[Explanation of symbols]

1 GPS receiver 2 latitude longitude detector 3 Autonomous navigation sensor 3a Distance sensor 3b Direction sensor 4 Moving amount detector 5 recording device 6 arithmetic unit e1 to e4 Self-contained navigation elements n1 to n3 self-contained navigation node points m1 to m3 GPS node points A starting point B Running end point C Actual travel path O measurement position M detected position

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-6-111196 (JP, A) JP-A-4-203930 (JP, A) JP-A-4-178587 (JP, A) JP-A-4- 50718 (JP, A) JP 5-297802 (JP, A) JP 63-5213 (JP, A) JP 5-18774 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (6)

(57) [Claims] 1. An absolute position measuring means for receiving an electric wave from a fixed radio station or a satellite to measure an absolute position of a moving body represented by latitude and longitude, and a relative position of the moving body by a distance sensor and a direction sensor. Traveling locus including relative movement amount measuring means for measuring various movement amounts, and computing means for obtaining a traveling locus of the moving body from absolute position data and relative movement amount data respectively measured in time series. In the measuring device, the absolute position measuring means and the relative movement amount measuring means are set to perform measurement at the same timing, and the calculating means obtains a relative traveling locus from the data of the relative movement amount, First means for selecting a point at which the moving body is bent by a predetermined angle or more from the relative traveling locus, and each point selected by the first means , A second means for obtaining the traveling direction and the position of the center of gravity from the data of the relative movement amount measured in time series between that point and the next point, and the point selected by the first means Third means for obtaining the traveling direction and the center of gravity position from the absolute position data measured at the same timing as, and the traveling direction and the center of gravity position obtained by the third means for the traveling obtained by the second means. A fourth means for correcting the relative positional relationship of the movement amount data between the two points in the second means so that the direction and the position of the center of gravity are substantially coincident with each other. Running locus measuring device. 2. The method according to claim 1, wherein the second means and the third means include means for linearly approximating the traveling direction by the least squares method and for obtaining the barycentric position by averaging the positions of the respective points. Running locus measuring device. 3. A means for re-correcting the traveling locus obtained from the movement amount data corrected by the fourth means so as to substantially coincide with a road map which is considered to have actually traveled. The travel locus measuring device according to claim 1 or 2. 4. The traveling locus measuring device according to claim 1, further comprising display means for displaying a traveling locus obtained from the corrected movement amount data on a screen. 5. The traveling locus measuring device according to claim 4, wherein the display means includes means for superimposing and displaying the traveling locus on a road map which is considered to have actually traveled. 6. A radio wave from a fixed radio station or a satellite is received to measure an absolute position of a moving body represented by latitude and longitude, and a relative movement amount of the moving body is measured by a distance sensor and a direction sensor. However, in the traveling locus measurement method for obtaining the traveling locus of the moving body from the absolute position data and the relative movement amount data measured in time series, the absolute position measurement and the relative movement amount measurement are performed at the same timing. Then, the relative traveling locus is obtained from the data of the relative movement amount, and the points where the moving body is bent by a predetermined angle or more are selected from the relative traveling locus, and for each selected point, The direction of travel and the position of the center of gravity are determined from the relative movement data measured in time series between that point and the next point, and the same point as the point selected from the relative travel locus is obtained. The traveling direction and the center of gravity position are obtained from the absolute position data measured by the MM, and the traveling direction and the center of gravity position obtained from the movement amount data relative to the traveling direction and the center of gravity position obtained from the absolute position data are substantially A traveling locus measuring method, characterized in that the relative positional relationship of the movement amount data between two points is corrected so as to match.