Positioning mark of aircraft, positioning method and positioning device of aircraft

Abstract

The invention relates to the technical field of vision measurement, and provides an aircraft positioning mark, a positioning method and an aircraft positioning device.The aircraft positioning mark comprises two or more squares, and the two or more squares comprise a first square and a second square; the second square is nested in the first square, four sides of the second square are parallel to four sides of the first square, and the center of the second square and the center of the first square are not at the same position. According to the scheme, visual positioning can be carried out, the calculation method is simple, and more position information of the unmanned aerial vehicle can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of visual measurement technology, and in particular to a positioning mark, a positioning method and a positioning device of an aircraft. Background Art

[0002] As drone applications in the industry become increasingly diversified, facing complex and harsh operating environments, reliability and intelligence have become important factors in measuring the maturity of drone systems. As part of the intelligent application of air-based robots, the drone vision-assisted positioning method can effectively avoid position offsets caused by unreliable satellite navigation signals in certain application scenarios.

[0003] The existing CN110989687A proposes to use a multi-layer square pattern with overlapping centers to guide the drone to land; this method has strict requirements on the pattern and can only be used for altitude calculation. The obtained position information is too little, which is not conducive to the intelligent application of aircraft.

[0004] Therefore, it is necessary to provide an aircraft positioning mark, a positioning method and an aircraft positioning device that can perform visual positioning, has a simple solution method, and can obtain more UAV location information.

[0005] The above information disclosed in the Background section is only for enhancement of understanding of the background of the present application and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] The main purpose of the present invention is to overcome the problem of obtaining less position information of the aircraft, and to provide an aircraft positioning mark, a positioning method and an aircraft positioning device, which can perform visual positioning, have a simple solution method, and can obtain more position information of the UAV.

[0007] To achieve the above-mentioned purpose, the present invention provides a first aspect of a positioning mark for an aircraft, comprising two or more squares, wherein the two or more squares include a first square and a second square;

[0008] The second square is nested in the first square, the four sides of the second square are parallel to the four sides of the first square, and the center of the second square is not at the same position as the center of the first square.

[0009] According to an exemplary embodiment of the present invention, the positioning mark of the aircraft further includes a third square, ..., an nth square, where n is a natural number greater than 2;

[0010] The nth square is nested within the n-1th square;

[0011] At least one of the positional relationship between every two mutually nested squares and the positional relationship between the other two mutually nested squares and the proportional relationship between every two mutually nested squares is different from that between the other two mutually nested squares.

[0012] According to an exemplary embodiment of the present invention, the first square and the second square have different colors, or the first square and the second square have the same color and the logo further includes an isolation graphic, the isolation graphic is nested in the first square, the second square is nested in the isolation graphic, the isolation graphic has a different color from the first square, and the isolation graphic is not a square.

[0013] According to an exemplary embodiment of the present invention, the aircraft positioning mark is a black and white mark.

[0014] According to an exemplary embodiment of the present invention, the ratio of the side lengths of the first square and the second square is in the range of (3-6):1.

[0015] As a second aspect of the present invention, the present invention provides a method for positioning an aircraft, comprising the following steps:

[0016] S1: Spread the positioning mark of the aircraft on the ground to obtain the world coordinates of each vertex of each square;

[0017] S2: The camera on the aircraft takes a downward shot of the positioning mark;

[0018] S3: Find each square in the image and obtain the image coordinates of each vertex of each square;

[0019] S4: Select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

[0020] According to an exemplary embodiment of the present invention, in step S3, finding each square in the image includes:

[0021] Image adaptive threshold binarization;

[0022] Extract all closed contours in the binary image;

[0023] Retaining the outline that satisfies the first picture size ratio relationship;

[0024] Preserve the outline of a convex polygon with four vertices;

[0025] Retain the contours whose lengths of the cross-connections between vertices satisfy the second proportional relationship;

[0026] Keep the contours whose lengths of the sequential lines between vertices satisfy the third proportional relationship;

[0027] Preserve contours whose vertices are not at the edge of the picture;

[0028] The four vertices of the contour are extracted, that is, a plurality of squares are obtained, and the image coordinates of each vertex of each square are acquired.

[0029] According to an exemplary embodiment of the present invention, in step S4, obtaining the position of the aircraft according to the image coordinates and world coordinates of each vertex of the two squares includes:

[0030] Get the direction of the camera based on the positional relationship between the largest square and the second largest square;

[0031] Order the four vertices of the largest square according to the direction of the camera;

[0032] According to the order of the four vertices, the positional relationship between the world coordinate system and the image coordinate system of the four vertices is matched by PnP solution to obtain the relative displacement transformation matrix;

[0033] The position information of the aircraft is obtained according to the relative displacement transformation matrix.

[0034] According to an exemplary embodiment of the present invention, obtaining the direction of the camera according to the positional relationship between the largest square and the second largest square includes:

[0035] Project the vertices of the two squares to the standard square;

[0036] The relative positions of the two squares are matched with the template of the aircraft's positioning mark to obtain the camera's direction.

[0037] As a third aspect of the present invention, the present invention provides a positioning device for an aircraft, comprising a positioning mark of the aircraft, a world coordinate acquisition module, a square image coordinate acquisition module and a position solution module;

[0038] The positioning mark of the aircraft is laid flat on the ground;

[0039] The world coordinate acquisition module is used to acquire the world coordinates of each vertex of each square;

[0040] The square image coordinate acquisition module is used to find each square in the image and obtain the image coordinates of each vertex of each square;

[0041] The position calculation module is used to select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

[0042] The advantages of the present invention are:

[0043] The present invention proposes a new eccentric asymmetric square mark, which has multiple squares with different positional relationships and proportional relationships. The position of the aircraft can be identified and located in three situations: combination, nesting and partial loss. It can cover operating conditions such as aircraft cruising, take-off and landing, and incomplete mark abnormalities, thereby expanding the scope of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and other objects, features and advantages of the present application will become more apparent by describing in detail the exemplary embodiments thereof with reference to the accompanying drawings. The accompanying drawings described below are only some embodiments of the present application, and it is clear to a person skilled in the art that other accompanying drawings can be obtained from these accompanying drawings without creative effort.

[0045] Figure 1 A schematic diagram of a positioning mark of a first type of aircraft is schematically shown.

[0046] Figure 2 A schematic diagram of a positioning mark of a second type of aircraft is schematically shown.

[0047] Figure 3 A schematic diagram of a positioning mark of a third type of aircraft is schematically shown.

[0048] Figure 4 A schematic diagram schematically shows the vertices of a square identifying a positioning mark of a first type of aircraft.

[0049] Figure 5 A schematic diagram schematically shows the vertices of a square identifying a positioning mark of a second type of aircraft.

[0050] Figure 6 The figure schematically shows the vertices of a square that identifies the positioning mark of the third type of aircraft.

[0051] Figure 7 The diagram schematically shows the steps of a method for positioning an aircraft.

[0052] Figure 8 The schematic diagram of an aircraft photographing a positioning mark is schematically shown.

[0053] Fig. 9 The schematic diagram of an aircraft photographing a positioning mark (another situation) is schematically shown.

[0054] Fig.10 The flowchart for identifying each square to obtain the image coordinates of each vertex is schematically shown.

[0055] Fig.11 The four directions of the positioning mark are schematically shown.

[0056] Fig.12The figure schematically shows a real shot of an aircraft photographing a positioning mark.

[0057] Fig.13 The figure schematically shows a real shot of an aircraft photographing a positioning mark (another situation).

[0058] Fig.14 The figure schematically shows the position change of the aircraft during a take-off and landing experiment. DETAILED DESCRIPTION

[0059] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0060] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0061] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0062] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0063] It should be understood that although the terms first, second, third, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0064] Those skilled in the art will appreciate that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0065] According to a first specific embodiment of the present invention, the present invention provides a positioning device for an aircraft, comprising a positioning mark for the aircraft, a world coordinate acquisition module, a square image coordinate acquisition module and a position solution module.

[0066] The aircraft's positioning mark is spread out on the ground.

[0067] The positioning mark of an aircraft includes more than two squares, and the more than two squares include a first square and a second square.

[0068] The second square is nested in the first square, the four sides of the second square are parallel to the four sides of the first square, and the center of the second square is not in the same position as the center of the first square. The first square and the second square have different colors, or the first square and the second square have the same color and the mark also includes an isolated graphic, the isolated graphic is nested in the first square, the second square is nested in the isolated graphic, the isolated graphic has a different color from the first square, and the isolated graphic is not a square. The recognized graphic is a square, which is easy to recognize, because the square has the characteristics of equal length of four sides and equal length of diagonals, while the rectangular feature is relatively not obvious and easy to misdetect, especially when observed at an inclined angle. Similarly, for example, the marking points are mostly marked with perfect circles instead of ellipses.

[0069] The ratio of the side lengths of the first square and the second square is (3-6):1. Figure 1 As shown, Figure 1 This is the positioning mark of the first case. The first square is a black square, and the second square is a white square. The second square is nested in the first square, and the center of the second square is not in the same position as the first square. The two are combined into an eccentric asymmetric square. Figure 4 The vertices of the marked squares can be clearly seen. Figure 2 As shown, Figure 2 For the positioning mark of the second case, the first square is a large black square, the isolation figure is a white rectangle, and the second square is a small black square. Figure 5 The vertices of the marked squares can be clearly seen. The isolation pattern is nested in the first square, and the second square is nested in the isolation pattern. The reason why the two squares are made of different colors or the isolation pattern is set in the middle is to clearly identify the sides and vertices of the squares.

[0070] Since the distance between the aircraft and the positioning mark is constantly changing, the framing range of the captured image is also constantly changing. Only two of the multiple nested squares are needed to complete the positioning of the aircraft. In order to adapt to different distances, the positioning mark of the aircraft also includes the third square,..., the nth square, where n is a natural number greater than 2.

[0071] The nth square is nested inside the n-1th square.

[0072] At least one of the positional relationship between each two mutually nested squares and the positional relationship between the other two mutually nested squares and the proportional relationship between each two mutually nested squares is different from each other. In this way, the relationship between the two mutually nested squares is unique, and the position information can be obtained more accurately and conveniently.

[0073] Similar to the first and second cases, the nth square is nested in the first square, the four sides of the nth square are parallel to the four sides of the n-1th square, and the center of the nth square is not in the same position as the center of the n-1th square. The n-1th square and the nth square have different colors, or the n-1th square and the nth square have the same color and the logo also includes an isolation graphic, the isolation graphic is nested in the n-1 square, the nth square is nested in the isolation graphic, the isolation graphic is different from the n-1 square, and the isolation graphic is not a square. The ratio of the side lengths of the n-1th square and the nth square is in the range of (3-6):1. Figure 3 As shown, Figure 3 This is the positioning mark of the third case, n is 3, the first square is a large black square, the isolated figure is a white rectangle, and the second square is a small black square. The isolated figure is nested in the first square, and the second square is nested in the isolated figure. The third square is white and nested in the second square. Figure 6 The vertices of the marked squares can be clearly seen.

[0074] As a preferred embodiment, the aircraft positioning mark is a black and white mark.

[0075] The world coordinate acquisition module is used to obtain the world coordinates of each vertex of each square.

[0076] The square image coordinate acquisition module is used to find each square in the image and obtain the image coordinates of each vertex of each square.

[0077] The position calculation module is used to select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

[0078] According to a second specific embodiment of the present invention, the present invention provides a method for positioning an aircraft, using the positioning device of the aircraft of the first specific embodiment, such as Figure 7 As shown, the following steps are included:

[0079] S1: Spread the aircraft's positioning mark on the ground and obtain the world coordinates of each vertex of each square.

[0080] S2: The camera on the aircraft takes a downward shot of the positioning mark.

[0081] like Figure 8 As shown, Figure 8 Two different positioning marks are set. The middle part of the dotted lines on the left and right sides represents the aircraft's downward field of view, where the left positioning mark can be photographed; the middle part of the left solid line and the right dotted line represents the overlapping field of view; the middle part of the left and right solid lines represents the aircraft's oblique field of view, where the right positioning mark can be photographed. When the drone continues to fly to the right, Fig. 9 As shown, the aircraft moves to the top of the right positioning mark. As long as the aircraft takes a picture of one of the positioning marks, the relative position relationship between the aircraft and the positioning mark can be obtained.

[0082] S3: Find each square in the image and obtain the image coordinates of each vertex of each square.

[0083] like Fig.10 As shown, finding each square in the image involves:

[0084] S31: Image adaptive threshold binarization.

[0085] S32: Extract all closed contours in the binary image.

[0086] S33: retaining the outline that satisfies the first screen size ratio relationship.

[0087] The first picture size ratio is that the total length of the contour line is between 0.03 times the larger value of the width and height of the image and 4 times the larger value of the width and height of the image; 0.03×max(w, h)≤total length of contour line≤4×max(w, h), where w represents the image width and h represents the image height; squares that are too large or too small in the picture will not be recognized to avoid false detection.

[0088] S34: Preserve the outline of a convex polygon with four vertices.

[0089] S35: retaining the contours whose lengths of the cross-connection lines between vertices satisfy the second proportional relationship.

[0090] The length ratio of the cross line X / Y is between 0.5 and 2, so that diamonds will not be misdetected. X and Y represent two cross lines respectively.

[0091] S36: retaining the contours whose lengths of the sequential connecting lines between vertices satisfy the third proportional relationship.

[0092] The length of each sequential line connecting the vertices A / B / C / D must account for more than 20% of the total length of A+B+C+D, so that irregular quadrilaterals will not be misdetected. A, B, C, and D represent four vertices respectively.

[0093] S37: Keep contours whose vertices are not at the edge of the picture.

[0094] S38: extracting four vertices of the outline, that is, obtaining a plurality of squares, and acquiring the image coordinates of each vertex of each square.

[0095] S4: Select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

[0096] The position of the aircraft is obtained according to the image coordinates of each vertex of the two squares and the world coordinates:

[0097] S41: Obtain the direction of the camera according to the positional relationship between the largest square and the second largest square.

[0098] The direction of the camera is obtained based on the positional relationship between the largest square and the second largest square:

[0099] Project the vertices of the two squares to the standard square;

[0100] The relative positions of the two squares are matched with the template of the aircraft's positioning mark to obtain the camera's direction.

[0101] The positional relationships that need to be confirmed are the positional relationship between the largest square and the second largest square, and the positional relationship between the second largest square and the third largest square.

[0102] The connection between each vertex is a processing step in the subsequent recognition process. Recognition has always been implemented based on four vertices. It is necessary to determine whether the four vertices are the four vertices of a square. The length information of the total four lines connecting two adjacent vertices is needed for judgment. The template of the aircraft's positioning mark is defined as a standard pointing diagram. The template of the aircraft's positioning mark is matched according to the relationship between the side length and the diagonal line. After the picture is rotated, it is easy to identify the change in pointing according to the relative relationship between the inner and outer squares.

[0103] like Fig.11 As shown, Fig.11 for Figure 1Schematic diagram of the positioning marks in the four directions. Figure 1 In the figure, the second largest square is close to the upper edge of the first largest square. The camera direction at this time is defined as pointing upward. Fig.11 (a) The camera points upward. Fig.11 (b) The camera points to the right. Fig.11 (c) The camera points downward. Fig.11 (d) The camera is pointing to the left. The advantage of the off-center square is that we can know the direction of the camera in the picture.

[0104] S42: Order the four vertices of the largest square according to the direction of the camera.

[0105] The four sequenced points are #0, #1, #2, and #3.

[0106] The sequencing is based on the template of the aircraft's positioning mark, such as Figure 4 As shown, the vertex of the upper left corner of the largest square is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3; the vertex of the upper left corner of the second largest square is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3. Similarly, Figure 5 In the figure, the vertex of the largest square in the upper left corner is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3; the vertex of the second largest square in the upper left corner is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3. Figure 6 In the figure, the vertex of the largest square in the upper left corner is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3; the vertex of the second largest square in the upper left corner is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3; the vertex of the third largest square in the upper left corner is #0, the vertex of the upper right corner is #1, the vertex of the lower right corner is #2, and the vertex of the lower left corner is #3.

[0107] Fig.12 for Figure 1 A real shot of the positioning mark, where the second largest square (white square) is on the left, and the lower left corner of the first largest square (black square) is identified as #0. The remaining corners are numbered clockwise, #1, #2, and #3. Fig.13 for Figure 1 Another real shot of the positioning mark. The second largest square (the white square is on the right), then we know that the camera is pointing to the right at this time, and we recognize that the upper right corner of the first largest square (the black square) is #0. Numbered clockwise, the remaining corners are #1, #2, and #3.

[0108] S43: According to the order of the four vertices, the positional relationship between the world coordinate system and the image coordinate system of the four vertices is matched by PnP solution to obtain a relative displacement transformation matrix.

[0109] In the camera image, the 2D coordinates of the square vertices on the image are directly or indirectly extracted, and the pose relationship between the 3D world coordinates and the 2D image coordinates is matched through PnP solution to obtain the relative displacement transformation matrix R / T, where R is the rotation matrix and T is the translation vector.

[0110] S44: Obtain the position information of the aircraft according to the relative displacement transformation matrix.

[0111] The world coordinate system includes the X-axis, Y-axis, and Z-axis. The position information includes: the X-axis offset, Y-axis offset, and the relative height between the aircraft and the ground (i.e., the Z-axis offset) of the aircraft in the world coordinate system. Fig.14 As shown, Fig.14 This is a diagram of the position of the aircraft in a certain take-off and landing experiment. The ordinate is the distance in meters, the abscissa is the time in seconds, h represents the relative height between the aircraft and the ground, X represents the X-direction offset of the aircraft in the world coordinate system, and Y represents the Y-direction offset of the aircraft in the world coordinate system. As a preferred embodiment, the X direction is due east, and the Y direction is due north. Fig.14 It can be seen that the present application can directly calculate the offset position of the aircraft only through simple positioning marks.

[0112] The present invention proposes a new eccentric asymmetric square mark, which has multiple squares with different positional relationships and proportional relationships. The position of the aircraft can be identified and located in three situations: combination, nesting and partial loss. It can cover operating conditions such as aircraft cruising, take-off and landing, and incomplete mark abnormalities, thereby expanding the scope of use.

[0113] The exemplary embodiments of the present invention are specifically shown and described above. It should be understood that the present invention is not limited to the detailed structure, configuration or implementation method described herein; on the contrary, the present invention is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A positioning mark for an aircraft, characterized in that: Includes more than two squares, the two or more squares include: a first square and a second square; The second square is nested in the first square, the four sides of the second square are parallel to the four sides of the first square, and the center of the second square is not at the same position as the center of the first square.

2. The aircraft positioning mark according to claim 1, characterized in that: It also includes the third square, ..., the nth square, where n is a natural number greater than 2; The nth square is nested within the n-1th square; At least one of the positional relationship between every two nested squares and the positional relationship between the other two nested squares, and the proportional relationship between every two nested squares and the proportional relationship between the other two nested squares is different.

3. The aircraft positioning mark according to claim 1, characterized in that: The first square and the second square have different colors, or the first square and the second square have the same color and the logo further includes an isolation graphic, the isolation graphic is nested in the first square, the second square is nested in the isolation graphic, the isolation graphic has a different color from the first square, and the isolation graphic is not a square.

4. The aircraft positioning mark according to claim 1, characterized in that: The aircraft positioning mark is a black and white mark.

5. The aircraft positioning mark according to claim 1, characterized in that: The ratio of the side lengths of the first square and the second square is (3-6):

1.

6. A method for positioning an aircraft, characterized in that: The following steps are involved: S1: Lay the positioning mark of the aircraft according to any one of claims 1 to 5 flat on the ground to obtain the world coordinates of each vertex of each square; S2: The camera on the aircraft takes a downward shot of the positioning mark; S3: Find each square in the image and obtain the image coordinates of each vertex of each square; S4: Select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

7. The method for positioning an aircraft according to claim 6, characterized in that: In step S3, finding each square in the image includes: Image adaptive threshold binarization; Extract all closed contours in the binary image; Retaining the outline that satisfies the first picture size ratio relationship; Preserve the outline of a convex polygon with four vertices; Retain the contours whose lengths of the cross-connections between vertices satisfy the second proportional relationship; Keep the contours whose lengths of the sequential lines between vertices satisfy the third proportional relationship; Preserve contours whose vertices are not at the edge of the picture; The four vertices of the contour are extracted, that is, a plurality of squares are obtained, and the image coordinates of each vertex of each square are acquired.

8. The method for positioning an aircraft according to claim 6, characterized in that: In step S4, obtaining the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates includes: Get the direction of the camera based on the positional relationship between the largest square and the second largest square; Order the four vertices of the largest square according to the direction of the camera; According to the order of the four vertices, the pose relationship between the world coordinate system and the image coordinate system of the four vertices is matched through PnP solution to obtain the relative displacement transformation matrix; The position information of the aircraft is obtained according to the relative displacement transformation matrix.

9. The method for positioning an aircraft according to claim 8, characterized in that: The obtaining of the direction of the camera according to the positional relationship between the largest square and the second largest square comprises: Project the vertices of the two squares to the standard square; The relative positions of the two squares are matched with the template of the aircraft's positioning mark to obtain the camera's direction.

10. A positioning device for an aircraft, characterized in that: include: The positioning mark, world coordinate acquisition module, square image coordinate acquisition module and position solution module of the aircraft according to any one of claims 1 to 5; The positioning mark of the aircraft is laid flat on the ground; The world coordinate acquisition module is used to acquire the world coordinates of each vertex of each square; The square image coordinate acquisition module is used to find each square in the image and obtain the image coordinates of each vertex of each square; The position calculation module is used to select the largest square and the second largest square, and obtain the position of the aircraft according to the image coordinates of each vertex of the two squares and the world coordinates.

Images