Flight path correction method

Abstract

To provide an unmanned aerial vehicle routing method that allows an unmanned aerial vehicle to continue flight after radio wave acquisition from GNSS is ceased, even if image data has not been acquired for a flight path.SOLUTION: A method of setting a flight path of an unmanned aerial vehicle includes: a first step of calculating the satellite acquisition state of the unmanned aerial vehicle based on the positional relationship between a satellite that constitutes a satellite positioning system and the unmanned aerial vehicle at any point along a planned route of the autonomous flight of the unmanned aerial vehicle; and a second step of comparing the acquisition state calculated in the first step with a reference acquisition state required for flight control of the unmanned aerial vehicle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for setting a flight path during the flight of an unmanned aerial vehicle (UAV).

Background Art

[0002] During the autonomous flight of a UAV, it flies along a planned flight path while acquiring radio waves related to position information from a Global Navigation Satellite System (GNSS) to confirm its own position. When the acquisition of radio waves from GNSS is interrupted, it is necessary to switch to manual operation by the operator or to implement landing at a safe area pre-programmed as a fail-safe function in the UAV.

[0003] In the case of manual operation by the operator, it is necessary to operate the UAV by visually observing the UAV or by referring to the image of a camera mounted on the UAV. Also, for the latter programming, since GNSS cannot be used, the position of the UAV itself cannot be confirmed. Therefore, there is a need for additional equipment such as landing at a safe area using image recognition by artificial intelligence (AI) from the video of the mounted camera, or deploying a parachute for a forced landing. However, safety is not always guaranteed.

[0004] Patent Document 1 discloses an image processing device that corrects the position and attitude angle based on the captured image and acquires an image of the sky above a specific area, even when the acquisition of radio waves from GPS (Global Positioning System), an example of GNSS, is interrupted. Patent Document 1 uses an image acquisition means mounted on a UAV to create an image database of images acquired during movement, and refers to the image database when the GPS link is interrupted. Then, it calculates the correlation value between the image in the image database and the current image, and performs coordinate transformation using the image with the highest correlation as a reference value to calculate an estimated error value of the position and attitude angle of the unmanned aircraft. The obtained estimated error value of the position and attitude angle is input into GPS / INS (Global Positioning System / Inertial Navigation System) calculation to detect the position and attitude angle. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-304260 [Overview of the project] [Problems that the invention aims to solve]

[0006] According to Patent Document 1, a UAV can continue flying even after the acquisition of GPS signals is interrupted. However, the UAV in Patent Document 1 is based on the premise that it will fly over a specific area multiple times, and it is necessary to acquire image data of the flight path in advance. In other words, the proposal in Patent Document 1 cannot be used when it is the first time to fly to the destination or when the flight path to the destination is unfamiliar. Therefore, the purpose of this disclosure is to provide a method for setting the flight path of a UAV that allows flight to continue without interrupting the acquisition of radio waves from GNSS, even if image data of the flight path has not been acquired. [Means for solving the problem]

[0007] The method for setting the flight path of an unmanned aerial vehicle related to this disclosure is: The first step involves calculating the satellite acquisition status of the unmanned aerial vehicle (UAV) at one of the points along the planned path of the autonomously flying UAV, based on the positional relationship between the satellites constituting the satellite positioning system and the UAV. The system comprises a second step of comparing the acquisition state calculated in the first step with a reference acquisition state necessary for flight control of the unmanned aerial vehicle, [Effects of the Invention]

[0008] According to this disclosure, a method for setting the flight path of a UAV is provided that allows the UAV to continue flying without interrupting the acquisition of radio waves from GNSS, even if image data of the flight path has not been acquired. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of a flight path set in the embodiment. [Figure 2] This diagram illustrates the maximum elevation angle θmax and the correction. [Figure 3] This diagram shows the relationship between the maximum elevation angle θmax and satellites capable of receiving radio waves. [Figure 4] This graph shows the relationship between multiple waypoints and the minimum altitude at which a sufficient number of satellites can be acquired for flight control. [Figure 5] This is a flowchart illustrating the control procedure in the embodiment. [Figure 6] This figure shows an example configuration of a control unit for executing the control procedure in the embodiment. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the attached drawings. In this embodiment, when setting the flight path before the UAV10 autonomously flies, it is determined whether the number of satellites acquired (satellite acquisition number) n that make up the GNSS has reached the reference satellite acquisition number N required for the flight control of the UAV10. In this embodiment, the satellite acquisition number n is calculated based on the elevation angle θ with respect to the environment surrounding the UAV10. In this embodiment, this determination result is reflected when determining the flight path. Here, an example of determining the satellite acquisition number n is described, but as will be described later, DOP (Dilution Of Precision), which is an indicator of positioning accuracy, can be used as a substitute for the satellite acquisition number n or as a target for determination together with the satellite acquisition number n.

[0011] [Flight path FP: See Figure 1] In this embodiment, the flight path FP shown in Figure 1 is set as an example. This flight path FP has WP1, WP2, WP3, WP4, WP5, WP6, and WP7 set as waypoints. Although only up to WP7 is shown here, the flight path FP has further waypoints such as WP8... A waypoint is point information on the flight path FP, and in this embodiment, it consists of three elements, for example, latitude (x), longitude (y), and altitude (z), as shown below. However, the following flight path FP is a provisional setting, and one of WP1 to WP7 is corrected based on the result of a determination made for the number of satellites acquired n, and the final flight path FP is determined.

[0012] Flight Path FP WP1:(x1,y1,z1) , WP2:(x2,y2,z2) WP3:(x3,y3,z3) , WP4:(x4,y4,z4) WP5:(x5,y5,z5) , WP6:(x6,y6,z6) WP7:(x7,y7,z7)

[0013] [Satellite acquisition failure: See Figures 2 and 3] The UAV 10 can fly autonomously by acquiring the information necessary to calculate its position relative to the ground. This information can be obtained from a Global Navigation Satellite System (GNSS). Examples of GNSS include GPS (Global Positioning System), QZSS (Japan), GLONASS (Russia), Galileo (EU), etc., and any of these systems can be used in this embodiment. These GNSS are composed of a plurality of artificial satellites (hereinafter simply referred to as satellites) orbiting around the Earth. Since the plurality of satellites constituting the GNSS orbit around the Earth, the positions of the satellites differ depending on the date and time. The relationship information between the date and time and the satellite positions in the GNSS is publicly available.

[0014] As an example, there are more than 30 satellites constituting GPS orbiting around the Earth, and each of them orbits 6 orbits in 12 hours. The GPS receiver equipped in the UAV 10 receives radio waves from at least 4 of these satellites and typically calculates its own position information by a calculation method called three-dimensional positioning. Therefore, the environment around the UAV 10 may become an obstacle, and it may not be possible to receive radio waves from the number of satellites necessary to calculate the position information, that is, it may not be possible to capture the satellites. The surrounding environment includes not only natural environments such as mountains and trees but also artificial environments such as high-rise building groups.

[0015] Since the flight path FP shown in FIG. 1 shows an example of traversing a mountainous area, the mountains can be an obstacle to satellite capture. FIG. 2 schematically shows the relationship between the UAV 10 and the obstacles 101 and 102 composed of the surrounding mountains at, for example, WP3. At WP3, the UAV 10 is sandwiched between the obstacle 101 and the obstacle 102. Comparing the elevation angles θ with respect to the vertex 101T of the obstacle 101 or the vertex 102T of the obstacle 102 with the UAV 10 as a reference, the elevation angle θ with respect to the vertex 101T is larger, forming the maximum elevation angle θmax at WP3. Note that the position of the UAV 10 at WP3 is known, and the position information regarding the obstacle 101 composed of mountains and the vertex 101T is also known as terrain data. Therefore, the elevation angle θ can be obtained by calculation. Also, although two obstacles, i.e., obstacle 101 and obstacle 102, have been described here, the maximum elevation angle θmax means the maximum elevation angle within the 360° azimuth with respect to WP3. Using the maximum elevation angle θmax is a preferable form that enables simple and quick calculations. However, it is also possible to calculate the elevation angle θ at predetermined angular intervals for the 360° azimuth and compare the number of satellite captures n with the reference number of satellite captures N for each calculated elevation angle θ.

[0016] Also, the angle of attack θ is such that the point where the straight line drawn from the UAV10 touches the outer contour line (ridge line) of the obstacle (the contact point) is the point that specifies the elevation angle θ. In the case of obstacles 101 and 102, the highest vertices 101T and 102T become the contact points. However, as in the case of obstacle 103 shown by the dashed line in Fig. 2 (Before), if the outer contour line includes, for example, an arc, the contact point 103C is a different point from the vertex 103T.

[0017] The larger the elevation angle θ with respect to the vertex of the obstacle, the greater the degree of obstacle to the capture of the satellites constituting the GNSS. Fig. 3 shows the situation of the capture of the maximum elevation angle θmax and a plurality of satellites 20. In Fig. 3, the solid-line satellites 20 indicate that the receiver equipped on the UAV10 has received and captured the radio waves, and the dashed-line satellites 20 indicate that they have not been captured by the UAV10. If the maximum elevation angle θmax becomes larger than that shown in the figure, the number of satellite captures n of the satellites 20 becomes smaller. Note that the capture number 4 in Fig. 3 is merely an example.

[0018] Let's assume that the maximum elevation angle θmax for WP3 shown in Figure 2 (Before) is insufficient to reach the number of satellites 20 required to determine the UAV10's position. For example, this would be the case when the GNSS is GPS and the number of acquired satellites n is 3. Therefore, with the default setting of WP3 (x3, y3, z3), the number of acquired satellites n is insufficient, and the UAV10's receiver cannot calculate its position. Thus, as shown in Figure 2 (After), the waypoint WP3 is corrected. Waypoint correction is performed by changing its position. More specifically, the correction position is obtained by changing either or both of the vertical V position and the horizontal H position. In the example shown in Figure 2, both the vertical V position and the horizontal H position are changed to correct it to, for example, WP3'(x3', y3', z3'). In WP3', there is also a maximum elevation angle θ'max, but the relationship between the pre-correction maximum elevation angle θmax and the maximum elevation angle θmax > maximum elevation angle θ'max is maintained, and the number of satellites 20 acquired at the maximum elevation angle θ'max is corrected to, for example, 4, so that the position can be calculated.

[0019] The simplest way to reduce the elevation angle θ is to change the altitude of the waypoint upwards in the vertical direction V. However, according to Japanese aviation law, for example, the flight altitude of a UAV10 is restricted to 150m or less in principle. Therefore, even if the number of targets n is secured by changing only the altitude, it will not be possible to comply with the flight altitude regulations. Thus, this embodiment allows selection of either correction to the vertical direction V or correction to the horizontal direction H, or both.

[0020] While the UAV10 is in flight, the control unit 11 can recognize the actual number of satellites acquired, n. However, at the stage of setting the flight path FP before flight, which is the target of this embodiment, the actual number of satellites acquired, n, cannot be recognized. Therefore, in this embodiment, the number of satellites acquired, n, is calculated based on the elevation angle θ. Since information on the satellites 20 that constitute the GNSS is publicly available, the number of satellites acquired, n, can be calculated by calculating the elevation angle θ.

[0021] [Minimum altitude required to secure the number of reference satellites N: Figure 4] While WP3 was used as an example above, the minimum altitude Hm required to secure the necessary number of reference satellites N to calculate the UAV10's position can also be identified for other waypoints such as WP1. Figure 4 shows an example of this. Note that Figure 4 only shows the altitude for each waypoint. In Figure 4, at WP1, the number of reference satellites N required to calculate the local position is secured when the altitude is 40m, and at WP3, the number of reference satellites N required to calculate the local position is secured when the altitude is 60m. At WP4 to WP7, the minimum altitude exceeds 100m, suggesting that the surrounding obstacles, such as mountains, are of high elevation.

[0022] [Example of route setting procedure with corrections: See Figures 5 and 6] Next, an example of a route setting procedure with corrections will be described. This route setting is performed before the UAV10 takes off, and the procedure shown in Figure 5 is executed by the control unit 11 of the UAV10 shown in Figure 6.

[0023] First, the flight path FP is set (Figure 5 S101). The flight path FP is set by setting multiple waypoints. The flight path FP at this time can be called a provisional flight path FP because it may be corrected in a later procedure. The provisional flight path FP is stored in the memory unit 11B of the control unit 11. Each waypoint includes three elements, as mentioned above: latitude, longitude, and altitude. The method for setting the flight path FP at this time is arbitrary; it can be set by a person based on terrain data, or it can be set by a computer device based on terrain data. In this case, the latitude and longitude are set according to the terrain data, but the altitude can be set to the same value for all waypoints. This is because in this embodiment, the altitude is likely to be subject to correction. In addition, the flight path FP can be set directly on the UAV 10, or it can be set outside the UAV 10 and saved on the UAV 10.

[0024] Next, for each of the provisionally set waypoints, the number of satellites acquired n and the number of reference satellites acquired N are compared and a determination is made. For this purpose, a waypoint is selected (Figure 5 S103). For example, if seven waypoints WP1 to WP7 shown in Figure 1 are set, WP1 is selected first, and the comparison determination of the number of satellites acquired n and the number of reference satellites acquired N at WP1 is performed. After the comparison determination of the number of satellites acquired n and the number of reference satellites acquired N at WP1 is completed, WP2 is selected next, and the comparison determination of the number of satellites acquired n and the number of reference satellites acquired N at WP2 is performed. Subsequently, the selection and comparison determination of WP3, WP4, ..., WP7 are performed. This comparison determination and correction are performed by the calculation unit 11C of the control unit 11, referring to the position information related to the flight path FP stored in the memory unit 11B.

[0025] When a waypoint is selected, the maximum elevation angle θmax at the selected waypoint is calculated (Figure 5 S105). This maximum elevation angle θmax is calculated by referring to pre-stored terrain data. As an example, in Japan, the Geospatial Information Authority of Japan can use data created by interpolating elevation values ​​at 5m intervals based on height data measured by aerial laser surveying.

[0026] Once the maximum elevation angle θmax is calculated, the number of satellites that can acquire information necessary to determine the position from the Global Navigation Satellite System (GNSS) at that waypoint, n, is calculated (Figure 5 S107). In calculating the number of satellites that can acquire n, the date and time on which UAV10 flies along the flight path FP is also taken into consideration. This is because, as mentioned above, the positions of the satellites that make up the Global Navigation Satellite System (GNSS) orbit the Earth and therefore differ depending on the date and time.

[0027] Once the number of acquired satellites n is calculated, its relative size is compared to the reference number of acquired satellites N at that waypoint (Figure 5, S109). If the number of acquired satellites n reaches the reference number of acquired satellites N (N ≤ n, S109 YES), no correction is needed to the setting information (latitude, longitude, and altitude) at that waypoint. If the number of acquired satellites n does not reach the reference number of acquired satellites N (N > n, S109 No), correction is needed to the setting information (latitude, longitude, and altitude) at that waypoint.

[0028] If correction of the setting information at the waypoint is necessary, one example is to increase the altitude of UAV10 among the setting information (latitude, longitude, and altitude) (Figure 5 S111). The increase in altitude can be set to a predetermined value, for example, A(m). If we are comparing and determining WP3, we correct it to Z3' by adding A(m) to z3 of WP3. Using the corrected altitude as Z3', we calculate the maximum elevation angle θmax (Figure 5 S107) and the number of satellites acquired n (Figure 5 S109). This procedure is repeated until the number of satellites acquired n reaches the reference number of satellites acquired N.

[0029] If it is determined that the number of captured satellites n has reached the reference number of captured satellites N (N ≤ n), then it is determined whether the altitude is higher than the altitude of the previous waypoint (Figure 5 S113). This is because it is possible that the number of captured satellites n does not exceed the reference number of captured satellites N between the previous waypoint and the waypoint currently being compared and judged. For example, if the waypoint currently being compared and judged is WP3, then its altitude is compared with the previous waypoint, WP2. If the altitude of WP3 is z3 and the altitude of WP2 is z2, then the relative magnitudes of z3 and z2 are compared. If the waypoint currently being compared and evaluated is WP3 and its altitude is z3, then the altitude of the previous waypoint, WP2, is corrected from z2 to z3.

[0030] Once the above comparisons, judgments, and necessary corrections are performed for all waypoints, the flight path FP is set and the UAV10 is ready for flight. The set flight path FP is stored in the memory unit 11B. When the UAV10 is flying autonomously, the memory unit 11B determines its own position using radio waves received from satellite 20 by the receiver unit 11A, and compares the flight path FP stored in the memory unit 11B with the determined position.

[0031] [Effects of the embodiment] According to this embodiment, the number of satellites n that constitute the Global Navigation Satellite System (GNSS) is calculated based on the elevation angle θ calculated by referring to terrain data, and the number of satellites n is compared with the number of reference satellites N required for flight control. Based on this comparison result, one or both of the vertical position (Pv) and / or horizontal position (Hv) of the UAV10 are changed. Therefore, according to this embodiment, the flight of the UAV10 can be ensured without interruption of radio wave acquisition from the GNSS.

[0032] It is possible to select or discard the configurations listed in the above embodiments, or to change them to other configurations as appropriate. The embodiments described above illustrate an example of comparing the number of satellites acquired n with the number of reference satellites acquired N for a waypoint, but this disclosure allows such comparison, determination, and correction processing to be performed at any point along the flight path. More specifically, this processing can be performed at predetermined intervals along the flight path, for example, at intervals of 100m.

[0033] The embodiments described above illustrate an example of applying the disclosure when setting a route before a UAV takes off, but the disclosure can also be applied to a UAV that is actually in flight. For example, while a UAV in flight can recognize the number of satellites it can acquire n, it cannot determine whether increasing the altitude of the UAV will secure the number of reference satellites N necessary for flight control. However, even if the number of satellites n acquired by a UAV in flight becomes insufficient, the number of reference satellites N necessary for flight control can be secured by applying the procedure shown in Figure 5, for example.

[0034] In the embodiments described above, the number of acquired satellites was used as the basis for comparison and determination. However, as an alternative to the number of acquired satellites, or in addition to comparing and determining the number of acquired satellites, DOP (Dilution Of Precision) can be used. DOP fluctuates depending on the geometric positional relationship between the UAV 10 (receiver 11A) and the satellite 20, and the smaller the value, the higher the positioning accuracy. In other words, DOP can also be considered information that identifies the acquisition status of the satellite 20, and DOP can be improved by correcting the position of the UAV. Here, the number of satellites acquired is determined based on the positional relationship between the satellites 20 constituting the GNSS and the UAV 10 (receiving unit 11A), and DOP is also a common acquisition state determined based on the positional relationship between the satellites 20 and the UAV 10 (receiving unit 11A). Therefore, in this disclosure, the positioning accuracy degradation coefficient d and the reference positioning accuracy degradation coefficient D can be compared and determined as substitutes for the number of satellites acquired n and the number of reference satellites acquired N, and the correction necessary for the UAV 10's route setting FP can be applied.

[0035] In the embodiments described above, an example was given in which the angle of attack θ is determined with respect to the vertices 101T and 102T of obstacles 101 and 102. However, depending on the shape of the obstacle, it may be necessary to determine the angle of attack θ with respect to a position other than the vertex. For example, consider an obstacle 103 whose outline (edge) is in the shape of a circular arc, as shown in Figure 2 (Before). In the case of this obstacle 103, if we compare the angle of attack θ with respect to the vertex 103T with the angle of attack θ with respect to the contact point 103C where a tangent line is drawn from the UAV 10 to the obstacle 103, the angle of attack θ with respect to the contact point 103C is larger and constitutes the maximum elevation angle θmax at WP3.

[0036] [Note] This disclosure can be interpreted as follows: [Note 1] The method for setting the flight path of an unmanned aerial vehicle is: The first step involves calculating the satellite acquisition status of the unmanned aerial vehicle (UAV) at one of the points along the planned path of the autonomously flying UAV, based on the positional relationship between the satellites constituting the satellite positioning system and the UAV. The system includes a second step of comparing the acquisition state calculated in the first step with a reference acquisition state required for flight control of the unmanned aerial vehicle. [Note 2] The method for setting the flight path in Appendix 1 is preferably: In the first step, Step 1-1 involves calculating the elevation angle θ at any point, Step 1-2 involves calculating the number of satellites n that can be acquired from the satellite positioning system to obtain the information necessary to calculate the position, based on the elevation angle θ calculated in step 1-1. In the second step, The calculated number of acquired satellites, n, is compared with the number of reference satellites, N, required for flight control. [Note 3] In the comparison of the second step in Appendix 2, If the number of captured satellites n does not reach the number of captured satellites N, Calculate a correction position that changes either or both of the vertical and horizontal positions of the unmanned aerial vehicle. Regarding the correction position, perform steps 1-1, 1-2, and 2. [Note 4] Preferably, with respect to the correction position in Appendix 3, the 1-1 step, the 1-2 step, and the 2 step are performed. If the number of acquired satellites n reaches the number of acquired satellites N (the reference satellite), the correction position is incorporated into the planned path. [Note 5] In the comparison of the second step of any of the appendices 1 to 3, preferably, If the number of satellites detected, n, reaches the baseline number of detected satellites, N, the planned flight path will be followed. [Note 6] In any of the first step 1 of Appendix 2 to Appendix 5, preferably, Calculate the maximum elevation angle θmax at the location. In steps 1-2, The number of captured objects n is calculated based on the maximum elevation angle θmax. [Note 7] In any of the appendices 2 to 5, preferably, the first and second steps are performed when setting the planned route. [Note 8] In Appendix 7, for multiple points separated by predetermined intervals along the planned route, or, For multiple waypoints along the planned route, perform steps 1 and 2. [Note 9] In any of the appendices 1 to 7, preferably, the first and second steps are performed when the unmanned aerial vehicle is autonomously flying according to the set planned route. [Note 10] In Appendix 1, preferably, In the first step, Calculate the positioning accuracy degradation coefficient d at any of the locations. In the second step, The calculated positioning accuracy degradation coefficient d is compared with the reference positioning accuracy degradation coefficient D required for flight control. [Explanation of Symbols]

[0037] 10 UAV 11 Control Unit 11A Receiver 11B Storage section 11C Arithmetic unit 20 satellites 101, 102, 103 Obstacles

Claims

1. A first step is to calculate the number of satellites the unmanned aerial vehicle (UAV) can acquire, n, based on the positional relationship between the satellites constituting the satellite positioning system and the UAV, for each of several points along the planned route of the autonomously flying UAV; The process is carried out in the following order: first step, the number of captured satellites n calculated in the first step is compared with the number of reference satellites N required for flight control of the unmanned aerial vehicle; second step, the number of captured satellites N required for flight control of the unmanned aerial vehicle; In the second step, if the number of acquisitions n at the location (WPn) has not reached the number of acquisitions N of the reference satellite, The system calculates a correction position that changes either or both of the vertical and horizontal positions of the unmanned aerial vehicle, and incorporates the calculated correction position into the planned route. In the second step, if the number of acquisitions n at the location (WPn) reaches the number of acquisitions N of the reference satellite, A flight path correction method that corrects the altitude (Z2) of the previous location (WPn-1) to the altitude (z3) of location (WPn) if the altitude (z3) at location (WPn) is higher than the altitude (z2) of the previous location (WPn-1).

2. In the first step described above, Step 1-1 involves calculating the elevation angle θ with respect to the top of the obstacle for satellite acquisition at any of the aforementioned points, Step 1-2 involves calculating the number of satellites n that can be acquired from the satellite positioning system based on the elevation angle θ calculated in step 1-1, and obtaining the information necessary to calculate the position from the satellite positioning system. In the second step described above, The calculated number of captured satellites n is compared with the number of reference satellites N required for flight control. The method for correcting a flight path according to claim 1.

3. In the comparison of the second step, If the number of captured satellites n has not reached the number of captured reference satellites N, A correction position is calculated that changes either or both of the vertical and horizontal positions of the aforementioned unmanned aerial vehicle. With respect to the correction position, the 1-1 step, the 1-2 step, and the 2 step are performed. The flight path correction method according to claim 2.

4. With respect to the correction position, the steps 1-1, 1-2, and 2 are performed. If the number of acquired satellites n reaches the number of acquired reference satellites N, the correction position is incorporated into the planned path. The flight path correction method according to claim 3.

5. In the comparison of the second step, If the number of acquired satellites n reaches the number of acquired reference satellites N, the planned route will be followed. The flight path correction method according to claim 2.

6. In step 1-1 above, The maximum elevation angle θmax at the aforementioned point is calculated, In the above steps 1-2, The number of captures n is calculated based on the maximum elevation angle θmax. The flight path correction method according to claim 2.

7. When setting the planned route, the first and second steps are performed. The method for correcting a flight path according to claim 1.

8. For a plurality of the aforementioned points separated by predetermined intervals along the aforementioned planned route, or, For multiple waypoints in the planned route, the first and second steps are performed. The flight path correction method according to claim 7.

9. The first and second steps are performed when the unmanned aerial vehicle is autonomously flying according to the set predetermined route. The method for correcting a flight path according to claim 1.

10. In the first step described above, The positioning accuracy degradation coefficient d at any of the aforementioned points is calculated, In the second step described above, The calculated positioning accuracy degradation coefficient d is compared with the reference positioning accuracy degradation coefficient D required for flight control. The method for correcting a flight path according to claim 1.

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