JP6501437B1 - Satellite positioning system and satellite positioning method - Google Patents

Abstract

To execute initialization of satellite positioning in a short time with high accuracy.
In a satellite positioning system, the position and attitude of a visual marker are determined. The movable body includes a visual marker detection unit, a signal reception unit that receives a positioning signal, and a storage unit in which the position and orientation of the visual marker are stored. The mobile body has an operation unit that executes satellite positioning based on the positioning signal after performing initialization processing in satellite positioning based on the position and orientation of the visual marker, and the operation unit is detected by the visual marker detection unit Based on the position and attitude of the visual marker, the estimated position of the moving body at a plurality of observation points in the earth fixed coordinate system is calculated. The operation unit calculates the positioning position of the moving object at a plurality of observation points in the earth fixed coordinate system by satellite positioning, and the operation unit measures movement trajectories connecting estimated positions at a plurality of observation points and positioning at a plurality of observation points The amount of change in the posture of the visual marker is calculated based on the movement locus connecting the positions.
[Selected figure] Figure 1

Description

  The present invention relates to a satellite positioning system and a satellite positioning method using a satellite.

  Satellite positioning methods include single carrier phase positioning (Precise Point Positioning (PPP)) and PPP-AR (Precise Point Positioning-Ambiguity Resolution) that improves the accuracy by finding an integer solution of carrier phase bias in PPP. . These positionings have a problem that it takes about several tens of minutes until initialization is completed and sufficient positioning accuracy is obtained.

  On the other hand, a visual marker is placed at a point where the position in the earth fixed coordinate system is known, and this visual marker is photographed by a camera mounted on a moving object, and the estimated position of the moving object obtained by this photographing is initial There is a method of significantly reducing the initialization time of PPP or PPP-AR by utilizing it (see, for example, Patent Document 1). Then, in order to perform initialization for obtaining sufficient positioning accuracy in a short time, it is necessary for the moving object to accurately and accurately hold information on the position and orientation of the visual marker in the earth fixed coordinate system.

JP 2018-009959 A

  However, even if the moving object precisely and accurately holds information on the position and orientation of the visual marker in the earth fixed coordinate system, if the visual marker moves from the original state for some reason, the moving object is The information about the position or attitude will deviate from the true value. In such a case, initialization may not be performed with sufficient positioning accuracy in a short time.

  In view of the circumstances as described above, it is an object of the present invention to provide a satellite positioning system and a satellite positioning method that execute satellite positioning initialization with high accuracy in a short time.

In order to achieve the above object, a satellite positioning system according to an aspect of the present invention comprises a visual marker and a mobile body.
In the visual marker, the position and attitude in the earth fixed coordinate system are determined.
The movable body has a visual marker detection unit that detects a visual marker, a signal reception unit that receives a positioning signal from an artificial satellite, and a storage unit in which information on the position and orientation of the visual marker is stored. Furthermore, the mobile body performs initialization processing in satellite positioning based on the position and orientation of the visual marker detected by the visual marker detection unit, and then performs satellite positioning in the earth fixed coordinate system based on the positioning signal Have a department.
The calculation unit calculates an estimated position in the earth fixed coordinate system of the moving object at a plurality of observation points based on the position and orientation of the visual marker detected by the visual marker detection unit.
The computing unit calculates the positioning position of the mobile in the earth fixed coordinate system at a plurality of observation points by satellite positioning.
The computing unit calculates the amount of change in posture of the visual marker based on a first movement trajectory connecting estimated positions at a plurality of observation points and a second movement trajectory connecting positioning positions at a plurality of observation points.

  With such a satellite positioning system, since the change amount of the posture of the visual marker can be calculated by overlapping the estimated position and the positioning position at a plurality of observation points, even if the visual marker deviates from the original state, the posture Can correct the change amount of Thereby, initialization of satellite positioning can be performed with higher positioning accuracy.

  In the satellite positioning system, when the operation unit rotates the first movement trajectory and the second movement trajectory around the satellite positioning start point, the i-th (0 ≦ i ≦ N) among the plurality of observation points , I is an integer, the 0th is the observation start point, the Nth is the observation end point, and the sum of the squares of the differences between the positioning position at the observation point and the estimated position at the i-th observation point The amount of rotation that is minimized by the least squares method may be used as the amount of change in posture of the visual marker.

  In such a satellite positioning system, the movement locus of the mobile object subjected to satellite positioning and the movement locus of the mobile object calculated based on the position and orientation of the visual marker are rotated around the satellite positioning start point. The amount of rotation when both movement trajectories substantially coincide with each other is set as the deviation of the posture of the visual marker. Since the amount of change in attitude is corrected based on the amount of rotation, initialization of satellite positioning can be performed with higher positioning accuracy.

The satellite positioning system may further include other visual markers in addition to the visual markers.
The arithmetic unit corrects the amount of change in the posture of the visual marker and the amount of change in the posture of the other visual marker using the calculated amounts of change in the posture, and then based on the position and the posture of the visual marker. The difference between the estimated position of the moving object calculated as described above and the estimated position of the moving object calculated based on the positions and orientations of the other visual markers may be calculated.
The arithmetic unit may compare the amount of change in posture and apply the difference to the amount of change in movement of the visual marker.

  In the case of such a satellite positioning system, for the visual marker of which the amount of change in posture is larger, it is calculated based on the estimated position of the moving object calculated based on the visual marker and the other visual markers. The difference from the estimated position of the moving object is estimated as the movement change amount of the visual marker. As a result, it is possible to correct the amount of movement change of the visual marker whose position has moved, and to perform initialization of satellite positioning with higher positioning accuracy.

  In the satellite positioning system, the operation unit may execute the initialization process based on the data of the position and orientation of the visual marker detected a plurality of times consecutively by the visual marker detection unit.

  According to such a satellite positioning system, the initialization processing is performed based on the data of the position and orientation of the visual marker detected a plurality of times by the visual marker detection unit, so that the estimation accuracy of the amount of change in orientation is improved. .

  As described above, according to the present invention, there are provided a satellite positioning system and a satellite positioning method that execute initialization of satellite positioning in a short time with high accuracy.

It is a conceptual diagram showing an example of a satellite positioning system concerning this embodiment. It is a schematic diagram explaining the method of computing the amount of change of the posture of the visual marker in a satellite positioning system. It is a schematic diagram explaining the method of computing the amount of change of the posture of the visual marker in a satellite positioning system. It is a schematic diagram explaining the method of calculating the movement change amount of the visual marker in a satellite positioning system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, three-dimensional coordinates may be introduced. Moreover, the same code | symbol may be attached | subjected to the member which has the same member or the same function, and after demonstrating the member, description may be abbreviate | omitted suitably.

  FIG. 1 is a conceptual view showing an example of a satellite positioning system according to the present embodiment.

  As shown in FIG. 1, the satellite positioning system 100 according to the present embodiment includes a mobile unit 200 and a visual marker 210. The moving body 200 includes a vehicle 201, a camera 202, a GNSS antenna 203, a storage unit 204, an operation unit 205, and a marker image processing unit 206. The visual marker 210 is supported by the support 212. The coordinate system EC in FIG. 1 means the earth fixed coordinate system EC, the coordinate system AC means the GNSS antenna coordinate system AC, and the coordinate system CC means the camera coordinate system CC. Further, the position of the mobile unit 200 is the position of the GNSS antenna 203 in the earth fixed coordinate system EC. Further, when defining the “posture” of the visual marker 210, the visual marker coordinate system MC fixed to the visual marker 210 with respect to the earth fixed coordinate system EC may be introduced.

  Before describing the operation of the satellite positioning system 100 according to the present embodiment, an outline of a PPP method using a visual marker 210, which is a prior invention described in Patent Document 1, will be described.

  In the satellite positioning system 100, the mobile unit 200 receives positioning signals transmitted from the positioning satellites (artificial satellites) 11, 12, 13, and 14 after the initialization process in the PPP method is executed, and the mobile unit 200 The position of 200 is measured with high accuracy.

  A plurality of positioning satellites 11, 12, 13, 14 are equipped with high-precision clocks. However, there may be an error in the clock ticks, and there may be an error in the orbits of the positioning satellites 11, 12, 13, 14. Furthermore, the positioning signals emitted from the positioning satellites 11, 12, 13, 14 propagate in the ionosphere and the troposphere before reaching the mobile unit 200. At that time, the signal may be delayed.

  In the PPP method, radio waves are received in advance from four or more positioning satellites, and observation results and models are used, errors of satellite orbits and satellite clocks, delay of signals by passing through the ionosphere and troposphere, carrier phase bias, etc. An initialization process is performed to estimate a large number of parameters. The initialization process is executed by the computing unit 205 mounted on the mobile unit 200 that is to perform satellite positioning based on the positioning signal. After the initialization process, it is possible to measure the exact position of the mobile unit 200 in the earth fixed coordinate system EC fixed to the earth.

  Conventionally, it has been said that it takes about several tens of minutes to one hour for the initialization process of the PPP method. This is because when the initial position estimation accuracy of the GNSS antenna 203 is not high, it is necessary to process a large number of satellite signals in order to obtain estimated values with sufficient accuracy when estimating positioning parameters including this position. It is because there is.

  Next, the operation of the satellite positioning system 100 of the present embodiment will be described.

  In this embodiment, an initialization process in the PPP system is adopted by adopting a method (see, for example, Japanese Patent Laid-Open No. 2018-009959) in which the visual marker 210 (see, for example, Japanese Patent No. 5842248) is incorporated into the satellite positioning system 100. Has been significantly shortened.

  For example, the position and orientation of the visual marker 210 in the earth fixed coordinate system EC are precisely determined in advance.

  Here, data regarding the position and orientation of the visual marker 210 determined in advance is stored in the storage unit 204 of the mobile unit 200. The data is associated with, for example, the ID number of the visual marker 210. Mobile unit 200 further includes a visual marker detection unit (for example, camera 202) and a signal reception unit (for example, GNSS antenna 203) for receiving positioning signals from positioning satellites 11, 12, 13, 14 There is.

  The relative positional relationship between the camera 202 and the GNSS antenna 203 is measured in advance. Next, the mobile unit 200 is activated, and the mobile unit 200 moves so that the visual marker 210 enters the field of view of the camera 202, and the camera 202 detects the visual marker 210.

  By precisely determining in advance the exact position and orientation of the visual marker 210, the computing unit 205 can use the GNSS antenna in the earth fixed coordinate system EC based on the position and orientation of the visual marker 210 detected by the camera 202. The estimated position of 203 is calculated.

  For example, the visual marker 210 is photographed by the camera 202 mounted on the movable body 200, the image thereof is input to the marker image processing unit 206, and the marker image processing unit 206 outputs the position, posture, ID and the like of the visual marker 210. Do. The computing unit 205 receives the information output from the marker image processing unit 206, and calculates the position and orientation of the visual marker 210 with respect to the camera 202 by a program mounted on the moving body 200. The marker image processing unit 206 and the calculation unit 205 may be collectively referred to as a calculation unit.

  From the data of the position and orientation of the visual marker 210 calculated by the program, the data of the position and orientation of the visual marker 210 accurately measured in advance, and the relative positional relationship between the camera 202 and the GNSS antenna 203, the earth The position and attitude (estimated position) of the GNSS antenna 203 in the fixed coordinate system EC can be obtained.

  Here, the timing when the camera 202 acquires the image of the visual marker 210 is triggered by the timing when the GNSS antenna 203 receives the signals from the positioning satellites 11, 12, 13, 14 and the signal output from the GNSS antenna 203 as a trigger. Synchronized Thereby, it is possible to synchronize the position of the mobile unit 200 calculated from the visual marker 210 captured while moving the mobile unit 200 with the position of the mobile unit 200 obtained by satellite positioning.

  The estimated data of the position and attitude of the GNSS antenna 203 thus obtained is used for measurement of positioning parameters of the PPP method. For example, the computing unit 205 performs initialization processing in satellite positioning based on the position and orientation of the visual marker 210 detected by the camera 202. After that, the computing unit 205 calculates the positioning position of the GNSS antenna 203 (mobile unit 200) in the earth fixed coordinate system EC based on the positioning signal.

  By introducing such an initialization process, the amount of information of the satellite signal conventionally required for the initialization process of the satellite positioning system is dramatically reduced, and the time required for the initialization process is significantly reduced. Ru. For example, the time is about several minutes. The initialization process at this stage is referred to as a first initialization process. The initialization process is completed at this stage if there is no change in the posture of the visual marker 210.

  However, the posture of the visual marker 210 may deviate from the state which has been precisely determined in advance by some factor (eg, environmental change, natural disaster, etc.). In such a case, a difference is generated between the true value of the attitude of the visual marker 210 and the value of the attitude of the visual marker 210 calculated by the satellite positioning system 100, and the initialization process may fail. For example, even if there is an error of about 30 mm in the translational direction and about 0.1 degree in the rotational direction, the initialization process may fail. Note that the state determined precisely in advance is called the "original state".

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 2018-009959), it is determined whether or not there is a difference between the value calculated by the satellite positioning system and the true value of the attitude of the visual marker 210 regarding the attitude of the visual marker 210. An approach has been proposed. However, in this method, the estimation of the amount of change in posture of the visual marker 210 is not mentioned. Furthermore, no reference is made to the estimation of the amount of change in the position at which the visual marker 210 is placed.

  On the other hand, in the satellite positioning system 100 according to the present embodiment, the earth fixed coordinates of the mobile object 200 at a plurality of observation points based on the position and orientation of the visual marker 210 detected by the camera 202 by the operation unit 205 Calculate the estimated position in the system EC. Next, the computing unit 205 calculates the positioning position in the earth fixed coordinate system EC of the mobile object 200 at a plurality of observation points by satellite positioning. Then, the calculation unit 205 calculates the amount of change in the attitude of the visual marker 210 based on the estimated positions and the measured positions at a plurality of observation points.

  Furthermore, in the satellite positioning system 100 according to the present embodiment, using the two visual markers 210, the operation unit 205 calculates the movement change amount of the visual marker 210 from the change amount of the posture of either of the two visual markers 210. Estimate

  First, a method of calculating the amount of change in posture of the visual marker 210 will be described.

  FIG. 2A to FIG. 2C are schematic diagrams illustrating a method of calculating the amount of change in attitude of the visual marker in the satellite positioning system.

  In the method of calculating the movement trajectory of the moving body 200, a method of capturing the visual marker 210 while moving and calculating the position of the moving body 200, and measuring the position of the moving body 200 by satellite positioning after initialization processing. There are two ways.

  For example, in FIGS. 2A and 2B, the Z-axis direction is the vertical direction with respect to the earth's ground, and the horizontal direction is the X-axis direction and the Y-axis A movement trajectory of the mobile unit 200 in the earth fixed coordinate system EC when the body 200 is viewed and a visual marker 210 in the earth fixed coordinate system EC are shown. Here, FIG. 2A shows the movement locus of the estimated position of the mobile unit 200, and FIG. 2B shows the movement locus of the positioning position of the mobile unit 200. As shown in FIG.

  Further, black circles in FIG. 2A and white circles in FIG. 2B indicate observation points of the moving body 200. By connecting the respective observation points with a line, the movement trajectory of the moving body 200 can be obtained. The estimated position and the positioning position may be calculated simultaneously or may be calculated independently. In FIGS. 2A and 2B, it is assumed that the posture of the visual marker 210 has not changed from the original state.

  In FIG. 2A, the position of the moving body 200 is calculated based on the image of the visual marker 210 captured by the camera 202 while the moving body 200 moves. The calculation of the position is performed at a plurality of observation points (black circles) from the start point to the end point. When these observation points are connected by a line, it becomes a movement locus, which is called movement locus A.

  On the other hand, in FIG. 2B, the position of the mobile unit 200 is calculated by satellite positioning after the initialization process. The calculation of the position is performed at a plurality of observation points (white circles) from the start point to the end point. When these observation points are connected by a line, it becomes a movement locus, which is called movement locus B.

  When the attitude of the visual marker 210 has not changed from the original state, the value of the attitude of the visual marker 210 stored in the satellite positioning system 100 matches the true value of the attitude of the visual marker 210, as shown in FIG. The movement trajectories A and B of (a) and (b) substantially coincide within the range of the measurement error. For example, FIG. 2C shows a state in which the movement trajectories A and B are superimposed on each other. As shown in FIG. 2C, the movement trajectories A and B substantially coincide with each other.

  Next, the movement locus of the mobile unit 200 when the posture of the visual marker 210 deviates from the original state will be described. As an example, the movement trajectory of the mobile unit 200 when the visual marker 210 is displaced about the Z axis will be described. In this case, the Z axis of the earth fixed coordinate system EC and the Z axis of the visual marker coordinate system MC become parallel.

  FIG. 3A to FIG. 3C are schematic diagrams illustrating a method of calculating the amount of change in the posture of the visual marker in the satellite positioning system.

  FIG. 3 (a) shows the estimated position of the mobile unit 200 calculated by the visual marker 210, and FIG. 3 (b) shows the positioning position of the mobile 200 calculated by satellite positioning. . Further, in FIGS. 3A and 3B, movement trajectories A and B depicted in FIGS. 2A and 2B are shown in an overlapping manner. The movement trajectories A and B are movement trajectories that can not be obtained when the posture of the visual marker 210 changes.

  In FIG. 3A, the visual marker 210 is photographed while the movable body 200 moves, and the position of the movable body 200 in the earth fixed coordinate system EC is calculated. The movement locus in FIG. 3A is a movement locus C (first movement locus).

  As in the visual marker 210 shown in FIG. 3A, when a change in posture occurs from the original state, the position of the mobile body 200 in the earth fixed coordinate system EC calculated using the visual marker 210 is the start point In the above, the position deviates from the position obtained using the true posture with a deviation σ.

  The deviation σ is an amount determined in accordance with the distance from the visual marker 210 to the moving object 200. For example, as the distance from the visual marker 210 to the moving object 200 increases, the change in posture of the visual marker 210 greatly affects the deviation. For example, when the moving object 200 approaches the visual marker 210 from the start point of the observation point and the distance from the visual marker 210 to the moving object 200 monotonously decreases from the start point of the observation point to the end point of the observation point Even with the deviation σ at the point, the deviation at the end point is smaller than the deviation at the start point.

  On the other hand, FIG. 3B shows how the position of the mobile unit 200 is calculated by satellite positioning after the initialization process. The movement locus in this case is a movement locus D (second movement locus).

  In the initialization of satellite positioning using the visual marker 210, if there is a deviation σ in the position of the moving object 200 obtained by the observation of the visual marker 210, the deviation σ is also superimposed on the positioning position obtained immediately after the initialization . The deviation σ gradually decreases with time regardless of the movement of the mobile unit 200, and the positioning position finally matches the positioning result in the case of the deviation 0.

  However, the rate of decrease of the deviation σ with the passage of time is extremely small. Therefore, if it is a short time (about several tens of seconds), it can be considered that the deviation σ of a fixed value is superimposed on the positioning position. Therefore, after the initialization process, the movement trajectory D of the moving object 200 obtained in a short time by satellite positioning is the orientation in the earth fixed coordinate system EC regardless of the position accuracy of each observation point where the satellite positioning is performed. Have high accuracy.

  That is, the orientation of the movement trajectory D in the earth fixed coordinate system EC substantially matches the orientation of the movement trajectory A. In other words, the movement locus D substantially matches the movement locus in which each observation point of the movement locus A is shifted by the deviation σ.

  Furthermore, the start point of the mobile unit 200 calculated by photographing of the visual marker 210 coincides with the start point of the mobile unit 200 calculated by satellite positioning. Therefore, as shown in FIG. 3C, the posture change amount of the visual marker 210 is a movement locus when the movement locus C and the movement locus D are rotated with the point at which the respective start points are superimposed as a fulcrum. It can be calculated as the amount of rotation when each observation point in C and D is most approximate. When the initialization processing is performed for each observation point in satellite positioning, the movement trajectory D substantially overlaps the movement trajectory C, and the amount of rotation can not be determined. When the amount of rotation is formulated, it becomes as follows.

・・・式（１）

・・・式（２）

... Formula (1)

... Formula (2)

Here, equation (2) is a determinant included in the absolute value, and is a rotation matrix that indicates the change in posture of the visual marker 210. p _{s, i} ^ENU0 is the position of the ith observation point determined by satellite positioning. p _{m, i} ^{ENU 0} is the position of the ith observation point obtained by observation of the visual marker 210. The subscript ENU0 has a start point as an origin, and indicates that each coordinate axis is a position in the earth fixed coordinate system EC corresponding to the east, north, and zenith directions. In equation (1), a determinant (2) including a parameter whose component is such that the sum Σ is minimized by the amount of rotation θ is determined.

  Based on this equation, the operation unit 205 moves the mobile object calculated based on the movement locus of the mobile object that has been satellite-positioned and the position and orientation of the visual marker 210 around the satellite positioning start point (fulcrum). When the locus is rotated, the i-th (0 i i N N, i is an integer, the 0th is the observation start point, the Nth is the observation end point) satellite positioning positions in the multiple observation points And the sum of the squares of the differences between the estimated position of the moving object and the estimated position of the moving object calculated based on the position and orientation of the visual marker 210 at the i-th observation point for all The amount of rotation θ is calculated as the amount of change in the posture of the visual marker 210.

  In order to improve the validity of the premise that the influence of deviation in initialization processing that appears in satellite positioning can be considered constant if it is a short time, as a method of satellite positioning, adopting a PPP scheme with a gradual and continuous convergence characteristic There is. In addition to the PPP method, when it is desired to perform Ambiguity Resolution (AR) to further improve the accuracy of the satellite positioning, the PPP method may be executed in parallel separately from the PPP-AR for this installation state change estimation.

  Further, the calculation unit 205 further reduces the rate of decrease of the deviation σ with the passage of time, and it can be considered that a constant deviation σ can be considered to be superimposed on the positioning position in a short time (about several tens of seconds). In order to further improve the feasibility and to improve the estimation accuracy of the posture change as a result, the initialization process may be performed based on the data of the position and orientation of the visual marker 210 continuously detected a plurality of times by the camera 202 . In this case, if the initialization processing is performed a plurality of times at each observation point where the distance between the observation points is large, the assumption that the deviation is constant does not hold, so that the observation point is sufficiently distant from the visual marker 210, for example, The initialization process is performed based on the data of the position and orientation of the visual marker 210 detected a plurality of times continuously near the point.

  Tables 1 and 2 show experimental results in which the amount of rotation (°) is estimated by the method of the present embodiment when the posture angle (°) of the visual marker 210 on the two-dimensional plane changes. Here, the error (°) is defined by the absolute value of the difference between the attitude angle and the rotation angle.

  Table 1 shows the results when the attitude angle changes (0 ° to 0.5 °), and Table 2 shows the results when the position change of +50 mm is further applied. In all cases, it was confirmed that the estimation error of the attitude angle was within 0.05 °. In particular, as shown in Table 2, even if the position change is added, the posture change can be estimated with high accuracy.

  Next, a method of estimating a change in the installation position of the visual marker 210 will be described. The change in the installation position of the visual marker 210 can not be estimated only by calculating the change in posture of the visual marker 210. In this case, the operation unit 205 estimates the movement change amount of the visual marker 210 from the change amount of the posture of either of the two visual markers 210A and 210B using the two visual markers 210A and 210B.

  FIG. 4 is a schematic view illustrating a method of calculating the movement change amount of the visual marker in the satellite positioning system.

  The satellite positioning system 100 shown in FIG. 4 includes another visual marker 210B in addition to the visual marker 210A.

  In the satellite positioning system 100 shown in FIG. 4, after the arithmetic unit 205 determines the amount of change in attitude of the visual marker 210A and the amount of change in attitude of the visual marker 210B by the method of the present embodiment, each change amount is calculated. Correction is made in advance using the calculated amount of change in posture. Thereby, the attitude | position precision in earth fixed coordinate system EC of each of visual marker 210A, 210B is high.

  Next, operation unit 205 calculates estimated position PA of movable body 200 based on the position and orientation of visual marker 210A, and calculates estimated position PB of movable body 200 based on the position and orientation of visual marker 210B. Here, when both of the visual markers 210A and 210B deviate from the original position, the true position PR of the moving body 200 can not be determined, and the estimated position of the moving body 200 is estimated by being shifted by ΔA from the position PR. The position PA and the estimated position PB shifted by δB from the position PR are obtained.

  Next, the calculation unit 205 calculates the difference (δB−δA) between the estimated position PA and the estimated position PB. The difference (δB−δA) is a difference between the amounts of change in the installation positions of the visual markers 210A and 210B.

  Here, among the visual markers 210A and 210B, it is assumed that the change amount of the posture of one visual marker is larger than the change amount of the posture of the other visual marker. For example, it is assumed that the amount of change in posture of one visual mar force is not zero and the amount of change in posture of the other visual marker is zero. In this case, there is a high possibility that only the position of the visual marker having the larger amount of posture is deviated from the original position.

  This is because when the position or orientation of the visual marker changes, the position and orientation are more likely to shift in an interlocking manner than when any one of the position or orientation is shifted. That is, in this case, it is reasonable to estimate the difference in positional change obtained by observing the two visual markers as it is as the positional change of the visual marker in which the change in posture occurs.

  In this case, it is possible to estimate the positional change of any visual marker of the two visual markers by using the difference between the positional changes of the two visual markers. That is, for the visual marker with the larger amount of change in posture, the difference in position change is applied to the amount of movement change of the visual marker. Then, the displacement of the movement of the visual marker is corrected based on the movement change amount.

  Furthermore, generally including the case where the amount of posture change of any visual marker is not 0, the installation state of the visual marker is modeled, and the correspondence relationship between the position change and the posture change is assumed in advance. Position changes may be assigned to visual markers according to the amount of rotation.

  According to the satellite positioning system 100 described above, the movement locus C and the movement locus are based on the movement locus C connecting estimated positions at a plurality of observation points and the movement locus D connecting positioning positions at a plurality of observation points By overlapping D, the change amount of the posture of the visual marker 210 is calculated. For example, when the movement locus C subjected to satellite positioning and the movement locus D are rotated around the satellite positioning start point, the amount of rotation when both movement loci substantially coincide with each other is the attitude of the visual marker 210. It is a gap.

  Thereby, even if the posture of the visual marker 210 deviates from the original state, it is possible to correct the amount of change in posture with high accuracy. If the amount of change in posture is accurately corrected, the initialization process to be performed again can be executed with high accuracy. As a result, satellite positioning can be performed with higher positioning accuracy. A change in posture of the visual marker 210 is detected, and an initialization process performed after correcting the amount of change in posture is referred to as a second initialization process. That is, the second initialization process is an initialization process performed when a change in posture of the visual marker 210 is detected.

  Further, in the case of the satellite positioning system 100, the change amounts of the postures of the visual markers 210A and 210B are compared, and the difference (δB−δA) is applied to the movement change amount of the visual markers. For example, the difference between the estimated position of the moving object calculated based on the visual marker and the estimated position of the moving object calculated based on the other visual markers, for the visual marker having the larger amount of change in posture. Is estimated as the movement change amount of the visual marker. As a result, it is possible to correct the amount of movement change of the visual marker whose position has moved, and it is possible to execute the initialization processing performed again with high accuracy. As a result, satellite positioning can be performed with higher positioning accuracy. The initialization process performed after correcting the movement change amount of the visual marker 210 is referred to as a third initialization process.

  Further, according to the satellite positioning system 100, the initialization process is executed based on the data of the position and orientation of the visual marker 210 detected a plurality of times by the camera 202, so that the estimation accuracy of the amount of change in orientation is improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, of course, a various change can be added. Each embodiment is not limited to an independent form, and can be combined as much as technically possible.

  Further, in the present embodiment, the case of using the PPP method as the satellite positioning method using GNSS has been described. However, the present embodiment is not limited to the PPP method as long as it is a satellite positioning method requiring no reference station and requiring time for initialization processing.

11, 12, 13, 14 ... positioning satellite 100 ... satellite positioning system 200 ... moving body 201 ... vehicle 202 ... camera 203 ... GNSS antenna 204 ... storage unit 205 ... operation unit 210, 210A, 210B ... visual marker 212 ... support base

Claims (5)

A visual marker whose position and orientation in the earth fixed coordinate system have been determined;
A visual marker detection unit that detects the visual marker, a signal reception unit that receives a positioning signal from an artificial satellite, a storage unit that stores information on the position and orientation of the visual marker, and the visual marker detection unit A mobile unit having an operation unit that executes the satellite positioning in the earth fixed coordinate system based on the positioning signal after performing initialization processing in satellite positioning based on the detected position and orientation of the visual marker Equipped with
The calculation unit calculates an estimated position of the moving body at a plurality of observation points in the earth fixed coordinate system, based on the position and the attitude of the visual marker detected by the visual marker detection unit,
Calculating a positioning position of the moving body at the plurality of observation points in the earth fixed coordinate system by the satellite positioning;
The amount of change in the posture of the visual marker is calculated based on a first movement trajectory connecting the estimated positions at the plurality of observation points and a second movement trajectory connecting the positioning positions at the plurality of observation points Satellite positioning system. A satellite positioning system according to claim 1, wherein
When the calculation unit rotates the first movement locus and the second movement locus around the satellite positioning start point,
The positioning position at the i-th (0 ≦ i ≦ N, i is an integer, the 0th is an observation start point, and the Nth is an observation end) observation points in the plurality of observation points, and A satellite positioning system, wherein the amount of rotation such that the sum of the sum of squares of differences with the estimated position for the plurality of observation points is minimized by a least squares method is the amount of change of the attitude of the visual marker. A satellite positioning system according to claim 1 or 2, wherein
In addition to the visual marker, it further comprises another visual marker,
The arithmetic unit corrects the change amount of the posture of the visual marker and the change amount of the posture of the other visual marker using each calculated change amount of the posture.
The difference between the estimated position of the moving body calculated based on the position of the visual marker and the attitude and the estimated position of the moving body calculated based on the position of the other visual marker and the attitude Calculate
The satellite positioning system which compares the said variation | change_quantity of each said attitude | position, and applies the said difference to the movement variation | change_quantity of a visual marker. The satellite positioning system according to any one of claims 1 to 3, wherein
The said positioning part performs the said initialization process based on the data of the said position of the said visual marker and the said attitude | position which were continuously detected in multiple times by the said visual marker detection part. A visual marker whose position and orientation in the earth fixed coordinate system are determined, a visual marker detection unit that detects the visual marker, a signal reception unit that receives a positioning signal from an artificial satellite, the position of the visual marker, and After initialization processing in satellite positioning is performed based on a storage unit in which information related to attitude is stored and the position and attitude of the visual marker detected by the visual marker detection unit, the earth is fixed based on the positioning signal Preparing a mobile body having an arithmetic unit for performing the satellite positioning in a coordinate system;
After the initialization process, based on the position and the attitude of the visual marker detected by the visual marker detection unit, an estimated position of the moving body at the plurality of observation points in the earth fixed coordinate system is calculated.
Calculating a positioning position of the moving body at the plurality of observation points in the earth fixed coordinate system by the satellite positioning;
The satellite positioning method which calculates the variation | change_quantity of the said attitude | position of the said visual marker based on the said estimated position and the said positioning position in these several observation points.

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