JP2018036151A - Positioning method using landmark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning method capable of measuring a current position of a mobile body even when the same is in an environment where an existing positioning method such as GPS is not available.SOLUTION: A mobile body comprises: surrounding environment information acquisition means which continuously acquires information on an environment surrounding the mobile body while the same is moving; azimuth direction acquisition means which acquires an azimuth direction of the mobile body; relative motion information acquisition means which acquires relative motion information with respect to the surrounding environment; first positioning means which, when two characteristic points become available at an arbitrary time, measures an own position using distances from respective characteristic points acquired by the surrounding environment information acquisition means and the azimuth direction; second positioning means which, when one characteristic point becomes available, estimates the own position on the basis of the distance from the characteristic point and an own azimuth direction acquired by the azimuth direction acquisition means; and third positioning means which, when no characteristic point becomes available, estimates the own position on the basis of the relative motion information acquired by the relative motion information acquisition means and a previous measurement result.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a positioning method for measuring the current position of a moving body, and more particularly to a positioning method using landmarks.

  Various positioning methods for measuring the current position of the moving body are known. For example, a positioning method for measuring the self-position by positioning using a GPS (Global Positioning System) is known.

  In addition, as described in Patent Document 1, even if it is a positioning method using GPS, when it becomes a situation where a transmission wave from a positioning satellite cannot be received, information obtained from an inertial device or the like, A positioning method is known in which self-position estimation accuracy is improved by correcting the self-position. The self-position estimation method acquires a feature point from a DBS (Doppler Beam Sharing) image obtained by a radar, and obtains the relationship between the acquired feature point and a previously obtained SAR (Synthetic Aperture Radar) map. By cross-referencing, the self-position is estimated using the position information of the corresponding known landmark on the SAR map and the distance information to the feature point obtained on the DBS image corresponding to the known landmark. Yes.

JP 2014-174070 A

  However, the above-mentioned conventional positioning method always keeps the position of the moving body in an environment where the positioning method using GPS or the like cannot be used when the moving body has entered the pier or the pier or when moving indoors. Since it becomes unknown, there is a problem that it is very difficult to guide the moving body safely and reliably. In addition, when the moving body involves some work, the work position cannot be managed, which is a fatal problem for the utilization of the moving body. Such a problem greatly hinders the introduction of mechanization in an environment where the above-described positioning method using GPS cannot be used.

  Therefore, the present invention has been made in view of the above problems, and provides a positioning method capable of measuring the current position of a moving object even in an environment where an existing positioning method such as GPS cannot be used. For the purpose.

  The positioning method according to the present invention is a positioning method in which positioning of a mobile object's own position is performed using landmark information included in map information, and information on the surrounding environment of the mobile object as the mobile object moves Peripheral environment information acquisition means for continuously acquiring, feature point extraction means for extracting one or more feature points from the peripheral environment information acquired at an arbitrary time by the peripheral environment information acquisition means, and the feature points Landmark acquisition means for associating the landmark information included in the map information acquired in advance, and the moving body includes the surrounding environment information acquisition means, an orientation acquisition means for acquiring its own orientation, and the surrounding environment. Relative motion information acquisition means for acquiring the relative motion information of each of the environmental information obtained by the surrounding environment information acquisition means when the two feature points can be acquired at the arbitrary time. A first positioning means for positioning the self-position using the distance and orientation from the syllable point; and the distance from the feature point and the self obtained by the orientation obtaining means when one of the feature points is obtained. A second positioning means for estimating the self-position based on the orientation of the first position, and a second position-estimating means for estimating the self-position from the relative motion information obtained by the relative motion information obtaining means and the previous measurement result when the feature point cannot be obtained. 3 positioning means are provided.

  In the positioning method according to the present invention, switching means for switching the first positioning means, the second positioning means, and the third positioning means according to the number of feature points acquired at the arbitrary time. Is preferably provided.

  In the positioning method according to the present invention, the position information estimated by the second positioning means and the third positioning means is converted into the own positioning information when the first positioning means is executed. Preferably, it is corrected.

  In the positioning method according to the present invention, it is preferable that an initial position acquisition unit that acquires an initial position of the moving body is provided.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these features can also be the invention.

  The positioning method according to the present invention includes a landmark acquisition unit that associates feature points with landmark information included in map information acquired in advance, and the mobile body acquires the surrounding environment information acquisition unit and its own direction. From the respective feature points obtained by the surrounding environment information obtaining means when two feature points can be obtained at an arbitrary time, including an orientation obtaining means and relative movement information obtaining means for obtaining relative movement information with the surrounding environment. The first positioning means for positioning the self-position using the distance and the orientation of the self-position, and when one feature point can be obtained, the self-position is determined by the distance from the feature point and the self-direction obtained by the orientation obtaining means. Second positioning means for estimating and third positioning hand for estimating the self-position from the relative motion information obtained by the relative motion information obtaining means and the previous measurement result when the feature point cannot be obtained. Since comprises, it is possible to perform a very high positioning of the moving body even efficacy in an environment where existing positioning methods are unavailable such as GPS.

The figure for demonstrating the outline | summary of the positioning method which concerns on embodiment of this invention. The flowchart of the positioning method which concerns on embodiment of this invention. The figure for demonstrating the outline | summary of the mobile body which concerns on embodiment of this invention. The figure explaining the outline | summary of the estimation method of a self-position. The flowchart of a 1st positioning means. The flowchart of a 2nd positioning means. The flowchart of a 3rd positioning means. The figure explaining the outline | summary of a 3rd positioning means. The figure for demonstrating the positioning method of the mobile body which concerns on embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is a diagram for explaining an outline of a positioning method according to an embodiment of the present invention, FIG. 2 is a flowchart of the positioning method according to the embodiment of the present invention, and FIG. FIG. 4 is a diagram for explaining an overview of a mobile object according to the embodiment, FIG. 4 is a diagram for explaining an overview of a self-position estimation method, and FIG. 5 is a flowchart of a first positioning means; 6 is a flowchart of the second positioning means, FIG. 7 is a flowchart of the third positioning means, FIG. 8 is a diagram for explaining the outline of the third positioning means, and FIG. These are the figures for demonstrating the positioning method of the mobile body which concerns on embodiment of this invention.

  As shown in FIG. 1, the positioning method according to the present embodiment performs measurement and observation while the moving body 10 moves on the lower surface of a structure 1 such as a pier in an environment where positioning technology such as GPS cannot be used. It is preferable to use as a positioning method for positioning the position of the moving body using the measurement results of the surrounding environment such as the piles 20 when performing operations such as the above.

  As shown in FIG. 2, the positioning method according to the present embodiment includes peripheral environment information acquisition means for continuously acquiring information on the surrounding environment of the moving body 10 as the moving body 10 moves, and acquisition of the surrounding environment information. Feature point extraction means for extracting one or more feature points from the surrounding environment information acquired at any time by means, and landmark acquisition means for associating the feature points with landmark information included in map information acquired in advance The mobile body 10 includes a surrounding environment information acquisition unit, a direction acquisition unit that acquires its own direction, and a relative motion information acquisition unit that acquires relative motion information with respect to the surrounding environment, and a feature point at an arbitrary time. The first positioning means that measures the self-position using the distance and direction from each feature point obtained by the surrounding environment information obtaining means when two can be obtained, and the case where one feature point can be obtained. A second positioning means for estimating the self-position based on the distance from the feature point and the own orientation obtained by the orientation obtaining means, and a relative motion obtained by the relative motion information obtaining means when the feature point cannot be obtained. A third positioning means for estimating the self position from the information and the previous measurement result is provided.

  As shown in FIG. 3, the moving body 10 includes a surrounding environment information acquisition unit 11, an orientation acquisition unit 12 that acquires its own orientation, and a relative motion information acquisition unit 13.

  As shown in FIG. 4, the surrounding environment information acquisition unit 11 may have any configuration as long as it can acquire information on the surrounding environment of the moving body 10. For example, a side such as an LRF (laser range finder) is used. It is preferable to use an area sensor. The LRF is an optical device that can oscillate a laser, irradiate the periphery of the moving body 10 with the laser, and acquire and measure information on the surrounding environment based on the degree of reflection. The surrounding environment information acquisition unit 11 can scan the surrounding environment as shown in FIG. 4 by irradiating laser or the like from the moving body 10 in two directions.

  The direction acquisition unit 12 may have any configuration as long as it can acquire its own direction. For example, a gyro sensor is preferably used. Moreover, the relative motion information acquisition means 13 is provided with a camera for image processing of the lower surface and the sea bottom of a measurement target such as a pier.

  As shown in FIG. 2, the positioning method according to the present embodiment includes an initial position acquisition unit that acquires the initial position of the moving object 10 when the loop determination determines that the positioning is the first time. ing. Since this initial position acquisition means is normally performed before moving to a measurement target such as a jetty, the moving body 10 is not yet on the lower surface of the measurement target, and position information such as GPS can be used. Therefore, it may be executed by acquiring position information from GPS. Moreover, it may replace with acquiring position information from GPS and you may comprise so that the initial position of the mobile body 10 in map information may be input manually.

  Next, feature point extraction means and landmark acquisition means will be described with reference to FIG. The feature point extraction unit selects an obstacle from the scanning result 31 obtained by the surrounding environment information acquisition unit 11 and observes the selected obstacle as the feature point 32. The scanning of the surrounding environment is continuously performed with the movement of the moving body 10, and the observation of the feature point 32 acquires the information on the surrounding environment acquired at an arbitrary time in time series.

  The landmark acquisition means matches the map information 30 including the landmark information 33 that is position information of an obstacle such as a pile with the scanning result 31 obtained by the surrounding environment information acquisition means 11 by performing correlation processing or the like. Thus, the scanning result 31 is mapped to the map information 30. As a result, the feature point 32 and the landmark information 33 are associated with each other.

  The switching means 14 is one of the first positioning means, the second positioning means, and the third positioning means depending on the number of feature points 32 acquired at an arbitrary time obtained by the surrounding environment information acquisition means 11. Switching the positioning method. Specifically, when two or more feature points 32 are acquired, switching to the first positioning unit is performed, and when one feature point 32 is acquired, switching to the second positioning unit is performed. If the data cannot be acquired, the mode is switched to the third positioning means.

  As shown in FIG. 5, the first positioning means performs positioning using a so-called lighthouse method, and specifically, features of two points in order from the obtained feature point 32 to the moving object 10 in order. A point is selected, and the observation direction of one nearest point among the feature points 32 (the direction of the nearest feature point viewed from the mobile object 10) and the length of the line segment connecting from that point to the mobile object 10 (the feature point 32) To the moving body 10). In addition, an angle formed by the X-axis in the coordinate system of the moving body (hereinafter referred to as the R coordinate system) and a line segment connecting the above-described two feature points is calculated.

  Next, the absolute azimuth of the moving body 10 in the world coordinate system (hereinafter referred to as the W coordinate system) is calculated. Specifically, the difference between the azimuth angle of the line segment connecting from the feature point 32 to the moving body 10 in the W coordinate system and the angle formed by the line segment as described above is obtained. The absolute azimuth of the moving body 10 is calculated by calculating the angle formed by the R coordinate system.

  Next, the position of the moving body 10 in the W coordinate system is calculated by converting from the R coordinate system to the W coordinate system. Specifically, the absolute position of the moving body 10 is calculated backward from the relative position between the angle (the absolute azimuth of the moving body 10) made by the R coordinate system and the nearest feature point with respect to the already calculated W coordinate system. The position of the moving body 10 is calculated.

  As described above, the first positioning means can calculate its own position information from the position of the feature point 32 in the R coordinate system, so that there is little positioning error, and the feature point is continuously observed and the positioning is continued. Even in this case, the cumulative error is zero in principle.

  As illustrated in FIG. 6, the second positioning unit acquires the estimated azimuth of the moving body 10 from the azimuth acquiring unit 12 when one feature point 32 is acquired. Next, the absolute azimuth of the moving body 10 in the W coordinate system is calculated. Specifically, the angle formed by the R coordinate system with respect to the W coordinate system is calculated from the azimuth obtaining unit 12, and the absolute azimuth of the moving body 10 in the W coordinate system is calculated from the angle formed by the R coordinate system with respect to the W coordinate system. If the orientation acquisition means 12 is a device that outputs a relative orientation, such as a gyro, the absolute orientation at the time when the feature point becomes one point or less is held as the initial value of the estimated orientation, and acquired here. The azimuth of the moving body 10 is estimated by adding to the initial value of the estimated azimuth that holds the relative azimuth.

  Next, the estimated position of the moving body 10 in the W coordinate system is calculated by converting from the R coordinate system to the W coordinate system. More specifically, the absolute position of the moving object 10 is calculated by back-calculating the absolute position of the moving object 10 from the relative position between the angle calculated by the R coordinate system (the absolute orientation of the moving object 10) and the nearest feature point with respect to the already calculated W coordinate system. The position of the body 10 is estimated.

  Thus, since the second positioning means can acquire the estimated azimuth by the azimuth acquiring means 12 even when only one feature point is obtained, the second positioning means is closest to the same as the first positioning means. The self-position can be estimated from the relative positions of the feature points.

  As shown in FIG. 7, the third positioning unit acquires the estimated azimuth of the moving body 10 from the azimuth acquiring unit 12 in the same manner as the second positioning unit when no feature point is obtained, and in the W coordinate system. The absolute azimuth of the moving body 10 is calculated. Also, the absolute position when no feature point is obtained is held as the initial value of the estimated position.

  Next, the absolute position of the moving body 10 is switched to an estimated position by dead reckoning using inertial navigation or relative motion information with respect to the surrounding environment. The relative motion information acquisition unit performs Doppler velocity log, odometry, or image processing using an optical flow on an image obtained from a camera provided in the moving body 10 as shown in FIG. The translational speed and the turning speed are estimated, and the relative motion information with the surrounding environment is acquired. The optical flow represents the motion of an object (such as a lower part of a floor board such as a pier) in images continuously acquired by a camera, and the translation speed and turning speed of the moving body 10 are calculated from the vector. . As a result, the obtained relative motion information with respect to the surrounding environment such as the translation speed and the turning speed is accumulated, and the accumulated value is added to the initial value of the estimated position holding the estimated position of the moving body 10.

  Thereafter, the positioning data is updated. The positioning data is updated by updating the landmark database in the R coordinate system by converting all landmark coordinates in the database held in the W coordinate system into the R coordinate system.

  Further, when the first positioning means is executed, by updating the estimated azimuth and the estimated position obtained by the second positioning means or the third positioning means with the current absolute azimuth and absolute position, It is corrected to positioning information. Since the estimated azimuth and the estimated position are usually accumulated values of observed values such as rate and relative speed, they include accumulated errors. Therefore, this correction can eliminate the accumulated errors and improve positioning accuracy.

  Next, with reference to FIG. 9, the positioning method of the moving body 10 according to the present embodiment will be described in detail. As described above, the moving object 10 observes the feature point 32 and acquires it in time series as information on the surrounding environment acquired at an arbitrary time. That is, the observation as shown in the positioning steps T to T + 2 in FIG. 9 is continuously performed. In the following description, an example in which landmarks in the W coordinate system are included as (1) to (4) as map information will be described.

  First, in the positioning step T, since two or more feature points 32 are observed, the mobile body 10 is positioned by the first positioning means described above, and the feature points 32 and the landmark coordinates are collated. The landmarks in the W coordinate system are collated. That is, the observed feature point 32 and the landmarks (1) to (3) in the W coordinate system are collated.

  Next, at the positioning step T + 1 performed after a short time from the positioning step T, two feature points 32 are observed. Since these two points are the landmarks (1) and (2) that overlap with the matching result of the previous positioning step T, the observation was performed at the positioning step T + 1 with the landmarks (1) and (2) collated in the positioning step T. It is estimated that the landmarks (1) and (2) are the same, and the landmarks (1) and (2) can be tracked at the positioning step T + 1.

  Next, a case where there are no overlapping landmarks as in the positioning step T + 1 and the positioning step T + 2 will be described. In the positioning method according to this embodiment, for the landmarks (3) and (4) that have not been detected in the positioning step T + 1, the geometric positional relationship between the landmarks on the map via the map information in each positioning step. Is estimated. Therefore, in the positioning step T + 2, the observed feature point 32 can be collated with the landmarks (3) and (4), and the landmarks (1) to (4) can be tracked.

  Thus, since the positioning method according to the present embodiment estimates the positions of all landmarks in the map information at each positioning step, the landmarks other than the landmarks that have been successfully verified at the previous positioning step. Can also be tracked, and a wide range of positioning can be realized. That is, the positioning method according to the present embodiment realizes wide-range positioning by performing positioning such as walking while handing over a plurality of landmarks.

  As described above, according to the positioning method according to the present embodiment, positioning is possible as long as map information including landmark information is provided even in an environment where positioning technology such as GPS cannot be used. Even in an environment where the positioning technology cannot be used, mechanization can be achieved for many operations.

  Further, according to the positioning method according to the present embodiment, the map information having the landmark information with respect to the positions of the landmarks set in advance is included, and the position of the landmark is determined by the geometric positional relationship between the landmarks. Therefore, positioning can be performed without separately preparing a feature for distinguishing individual landmarks.

  Furthermore, according to the positioning method according to the present embodiment, since the first to third positioning means are switched according to the number of available landmarks, the positioning method can be flexibly changed from the obtained information. In addition, even when the number of available landmarks decreases, this can be compensated for by the other upper direction, so that positioning can be performed more flexibly.

  In the positioning method according to the present embodiment described above, for example, the case where image processing is performed while photographing the floor surface of the pier with the relative motion information acquisition unit has been described, but the relative motion information acquisition unit captures the image. The target to be processed is not limited to the floor plate surface, and for example, image processing may be performed while photographing the sea bottom. In addition, a computer program for executing the positioning method according to the present embodiment can be read by a computer. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Mobile body, 11 Surrounding environment information acquisition means, 12 Direction acquisition means, 13 Relative motion information acquisition means, 20 Pile, 30 Map information, 31 Scan result, 32 Feature point, 33 Landmark information.

Claims (4)

A positioning method for performing positioning of a mobile object using landmark information included in map information,
Surrounding environment information acquisition means for continuously acquiring information on the surrounding environment of the moving body as the moving body moves,
Feature point extracting means for extracting one or more feature points from the surrounding environment information acquired at an arbitrary time by the surrounding environment information acquiring means;
Landmark acquisition means for associating the feature points with the landmark information included in the map information acquired in advance;
The mobile body includes the surrounding environment information acquisition means, an orientation acquisition means for acquiring its own orientation, and a relative motion information acquisition means for acquiring relative motion information with the surrounding environment,
First positioning means for performing self-position positioning using distances and directions from respective feature points obtained by the surrounding environment information obtaining means when two feature points can be obtained at the arbitrary time; The second positioning means for estimating the self-position based on the distance from the feature point and the self-direction obtained by the azimuth obtaining means when one feature point is obtained, and the feature point cannot be obtained. And a third positioning means for estimating the self-position from the relative motion information obtained by the relative motion information acquisition means and the previous measurement result. The positioning method according to claim 1,
A positioning method comprising switching means for switching the first positioning means, the second positioning means, and the third positioning means in accordance with the number of feature points acquired at the arbitrary time. In the positioning method according to claim 1 or 2,
The position information estimated by the second positioning means and the third positioning means is corrected to the own positioning information when the first positioning means is executed. . The positioning method according to any one of claims 1 to 3,
A positioning method comprising initial position acquisition means for acquiring an initial position of the moving body.

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