A Method for Calculating Flight Path and Anti-Collision of a Low-Altitude Aircraft

Abstract

The present invention is applicable to the field of flight technologies of low-altitude airspace vehicles, and provides a method for calculating flight path and anti-collision of a low-altitude vehicle, including: obtaining three-dimensional dimension data of the vehicle, and determining the corresponding earth grid level of the current vehicle according to the maximum dimension; establishing a path data set; calculating the grid set passed by the flight path. During anti-collision analysis, according to the code of the grid unit where the current vehicle is located and the distance from the center point, the spatial relationship between grid units is judged, and thus the spatial relationship of the vehicle can be obtained. The present invention does not display the path in the form of coordinate points, but displays the flight path in the form of earth grid units in three-dimensional space, making the path display more intuitive, the position more realistic and comprehensive, and also facilitating subsequent collision analysis; moreover, by judging the spatial relationship between the grid units where the vehicle is located, the problem of anti-collision detection during the flight of the vehicle in low-altitude airspace is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-altitude airspace vehicle flight technology, and particularly relates to a method for calculating flight path and anti-collision of a low-altitude vehicle. Background Art

[0002] With the continuous increase in the number of vehicles in the low-altitude airspace, how to effectively prevent collisions between vehicles has become a key technical problem urgently needed to be solved in the development of the low-altitude industry. This challenge not only relates to flight safety but also directly affects the sustainable development of the low-altitude economy and the efficiency of the entire airspace management. In this context, various advanced flight monitoring technologies, intelligent anti-collision systems, and unmanned aircraft autonomous flight technologies are being actively researched and applied in order to build a safer, more efficient, and intelligent low-altitude flight environment.

[0003] Regarding the anti-collision research of low-altitude airspace vehicles, firstly, it is necessary to obtain the flight path of the vehicle. In the prior art, generally, the longitude and latitude coordinates are directly recorded, but the coordinate data cannot intuitively reflect the position of the vehicle, especially only the position at the sampling time point can be recorded, and the path information between two sampling points cannot be reflected. In addition, when calculating anti-collision between vehicles, generally only the coordinate distance is calculated, and early warnings cannot be given separately according to different position situations. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for calculating flight path and anti-collision of a low-altitude vehicle, aiming to solve the technical problems in the prior art that the path calculation display is not intuitive and complete, and the anti-collision early warning is not specific enough.

[0005] The present invention adopts the following technical solutions:

[0006] On the one hand, the method for calculating the flight path of the low-altitude vehicle includes the following steps:

[0007] Step S1, obtain the three-dimensional size data of the vehicle, and determine the earth grid level corresponding to the current vehicle according to the size of the earth grid unit at the earth grid level, with the maximum size;

[0008] Step S2, obtain the flight path data of the vehicle and establish a path data set, where the flight path data is the earth space coordinate data at each time point;

[0009] Step S3, calculate the grid set of the earth grid level passed by the flight path of the vehicle according to the path data set.

[0010] In addition, it also includes:

[0011] Step S4: In three-dimensional space, display the set of grids passed by the aircraft as the flight path of the aircraft.

[0012] On the other hand, the anti-collision method of the low-altitude aircraft, including the flight path calculation method of the low-altitude aircraft, further includes:

[0013] Step S5: For two aircraft F1 and F2, obtain the position points at time t from the set of grids of the corresponding flight paths and the grid cells and , and obtain the corresponding codes and ;

[0014] Step S6: According to the relationship between and , and the distance between the center points of the grid cells and , judge the spatial relationship between the grid cells and , including coincidence, inclusion, adjacency, and separation;

[0015] Step S7: If the spatial relationship and between the grid cells is a coincidence or inclusion relationship, the aircraft F1 and F2 will collide; if the relationship and between the grid cells is an adjacency relationship, there is a risk of collision between the aircraft F1 and F2; if the relationship and

[0016] between the grid cells is a separation relationship, the aircraft F1 and F2 will not collide.

[0017] The beneficial effects of the present invention are as follows: In the technical solution of the present invention, the space is divided according to the earth grids, and the earth grid cells passed by the flight path of the aircraft are recorded to generate a grid set. The path is not displayed in the form of coordinate points, but in the form of earth grid cells in three-dimensional space, making the path display more intuitive, the position more realistic and comprehensive, and it is also beneficial to subsequent collision analysis. In addition, the present invention analyzes whether or not there will be a collision between low-altitude aircraft by judging the spatial relationship between the grid cells where the aircraft are located, and solves the problem of anti-collision detection during the flight of aircraft in low-altitude airspace. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a flowchart of a method for calculating the flight path of a low-altitude aircraft provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the division of the Earth's grid at different levels;

[0019] Figure 3 It is a schematic diagram of traversing the situation where the grid cell codes corresponding to two points are the same;

[0020] Figure 4 It is a schematic diagram of traversing the situation where the grid cell codes corresponding to two points are different;

[0021] Figure 5 It is a flowchart of a collision prevention method for a low-altitude aircraft provided by an embodiment of the present invention;

[0022] Figure 6 It is a planar schematic diagram of the spatial relationship of the Earth's grid cells at the same level and different levels. Detailed implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] In order to illustrate the technical solutions described in the present invention, the following will be described through specific embodiments.

[0025] Embodiment 1:

[0026] As Figure 1 shown, this embodiment provides a method for calculating the flight path of a low-altitude aircraft, including the following steps:

[0027] Step S1, obtain the three-dimensional size data of the aircraft, and determine the Earth grid level corresponding to the current aircraft based on the size of the Earth grid cells at the Earth grid level with the maximum size.

[0028] The low-altitude aircraft has three size data of length, width and height. Assume that the three-dimensional size data of the length, width and height of the current aircraft are , and the maximum aircraft size dF1 = , where max is to find the maximum value.

[0029] The Earth space is divided into three-dimensional grids at different levels, and the sizes of the grid cells of the Earth grids at different levels are different. For example, as a division method, as Figure 2As shown in the figure, the side length of the upper-level grid cell is twice that of the lower-level grid cell, that is, one upper-level grid cell can correspond to 8 lower-level grid cells, and the Earth space can be divided into grid cells of different levels from top to bottom. Each level divides the entire Earth space.

[0030] After the grid is divided, each level of grid cell has a corresponding size length. Use to represent the next-level grid cell of to represent the length of the size of the -level Earth grid cell. According to the size dF1 of the aircraft F1 and the size of the Earth grid cell, determine the Earth grid level corresponding to the aircraft F1.

[0031] If < dF1 ≤ , then the Earth grid level corresponding to the current aircraft is considered to be .

[0032] Step S2, obtain the flight path data of the aircraft to establish a path data set, where the flight path data is the Earth space coordinate data at each time point.

[0033] For example, there are Earth space coordinate data recorded at n time points, and the established path data set is: , and each Earth space coordinate data in the set consists of longitude, latitude, and altitude data.

[0034] Step S3, according to the path data set, calculate the grid set passed by the flight path of the aircraft at the current Earth grid level.

[0035] Still taking the low-altitude aircraft F1 as an example, its path data set is: , and the specific process of this step is as follows:

[0036] S31. Traverse each Earth space coordinate data in the path data set , take out two adjacent points in sequence. For the two points obtained currently, , where 1 ≤ i ≤ n - 1, construct the line segment equation of the two points :

[0037] ;

[0038] S32. According to the coordinate data of the two points and , judge whether the two points are in the same grid cell, and establish a grid set. The specific process of the judgment process of this step is as follows:

[0039] 321. Calculate the location of two points Hierarchical Earth grid cells and , where the point Location Hierarchical Earth grid cells is calculated as follows:

[0040] ;

[0041] in, To round up, 、 、 Represents the earth grid cells The ordinal value in the longitude, latitude, and altitude directions in the current level of the earth grid.

[0042] For point , whose three-dimensional coordinates are Since the earth grid is divided into three-dimensional grids in the reverse direction of longitude, latitude and altitude, the coordinate component is divided by the grid unit size and then rounded up to get the current point. The relative position of the grid cell in the entire earth space.

[0043] 322. Get the Earth grid cells by number and The corresponding codes are and , and the Earth grid cells Add to Grid Collection .

[0044] The earth space division and coding in this embodiment refer to "Earth Surface Spatial Grid and Coding" (GJB 8896-2017). Each level of grid cells has a fixed coding method, so the coding of grid cells at different levels is different.

[0045] Therefore, in the earth grid unit 、 After the location information is obtained, it is encoded according to the fixed encoding method to obtain the corresponding code and Then Add to Grid Collection middle.

[0046] 323. If , it means that the two points are in the same earth grid unit Inside, at this time Figure 3 As shown, the explanation points arrive The path between only passes through grid cells , and no action is required at this time. Then return to step S31 to traverse the next adjacent two points, that is, take and , and add to the grid set in the above manner.

[0047] If , it means that point and point are in different grid cells. As shown in Figure 4 , with as the center of the sphere and as the sphere radius, construct the sphere equation :

[0048] ;

[0049] Simultaneously solve the line segment equation and the sphere equation to find the intersection point , and then construct the line segment equation with point . Then repeat the method in step S32 to determine whether point and point are in the same grid cell (that is, judge whether the corresponding codes are the same); if they are in the same grid cell (in the figure, and are in the same grid cell), then add the corresponding Earth grid cell of point to the grid set in the grid set ; if they are in different grid cells, then construct the sphere equation and the line segment equation again for judgment, and continuously update the grid set.

[0050] Therefore, through the above judgment method, each time two adjacent points are taken, the starting point and the grid cells passed between the two points are added to the grid set in the grid set .

[0051] S33. After the traversal of the path data set is completed, the final grid set representing the flight path of the aircraft is obtained.

[0052] Step S4. In three-dimensional space, display the grid set passed by the aircraft as the flight path of the aircraft.

[0053] For the convenience of displaying the path, in this embodiment, the aircraft displays each grid cell in the grid set on the three-dimensional space interface as the flight path of the aircraft. In this way, the position of the aircraft can be observed more intuitively, and at the same time, it is also convenient to display the grid cells passed between the sampling points, and the data is richer. Moreover, through this grid set, a foundation is laid for subsequent anti-collision judgment.

[0054] Embodiment 2:

[0055] This embodiment provides an anti-collision method for the low-altitude aircraft, as Figure 5 shown, including the following steps:

[0056] Step S5: For two aircraft F1 and F2, obtain the position points at time t from the grid sets corresponding to their respective flight paths and the grid cells and where they are located, and obtain the corresponding codes and .

[0057] When it is necessary to judge the spatial relationship between two aircraft F1 and F2, in Embodiment 1, the grid set corresponding to the flight path of aircraft F1 has been obtained. Similarly, the grid set corresponding to the flight path of aircraft F2 can also be obtained, and the specific process will not be elaborated here.

[0058] Although the grid set stores the grid cells where the aircraft is located at each sampling time point and the grid cells passed by the aircraft between the sampling points, and they are stored in sequence, each grid cell in the grid set has time point information. Therefore, the grid cell where the position point corresponding to time point t is located can be directly obtained and then encoded, which are and respectively.

[0059] Step S6: According to the relationship between and , and the distance between the center points of the grid cells and , judge the spatial relationship and between the grid cells, including coincidence, inclusion, adjacency, and separation. , including coincidence, inclusion, adjacency, and separation.

[0060] Combined with Figure 6 shown, coincidence means that the two grid cells are the same grid cell; inclusion means that one small grid cell is within another large grid cell; adjacency means that the two grid cells have an adjacent face or adjacent edge or adjacent vertex; separation means that the two grid cells do not have adjacent points, edges, or faces, and are not in an inclusion or coincidence relationship.

[0061] The specific process of this step is as follows:

[0062] S61. The level where the aircraft F1 is located is , and the level where the aircraft F2 is located is . Obtain the grid cells where the two aircraft are located and . According to the earth grid division rules, obtain the center point coordinates corresponding to the grid cells and , which are respectively ( , , ), ( , , ), as well as the side length and diagonal length of the grid cell. Among them, the side lengths of the grid cells and are respectively , , and the diagonal lengths are respectively , ;

[0063] S62. According to the center point coordinates ( , , ), ( , , ), calculate the distance and : :

[0064] ;

[0065] If , then is coincident;

[0066] If and and , then is adjacent;

[0067] If and and , then is separated;

[0068] If and and , then is inclusive, where represents taking the encoding of the first digit encoding;

[0069] If and and , then is adjacent;

[0070] If and and , then is adjacent;

[0071] If and and and , then is separated;

[0072] If and and and , then is separated.

[0073] Step S7. Determine the collision situation of two aircraft according to the spatial relationship: If the spatial relationship between and is a coincidence or inclusion relationship, then the aircraft F1 and F2 will collide; if the relationship between and is an adjacent relationship, then there is a risk of collision between the aircraft F1 and F2; if the relationship between and is a separated relationship, then the aircraft F1 and F2 will not collide.

[0074] Therefore, through the above judgment method, according to the size of the low-altitude airspace aircraft, obtain the grid set of the flight path, and then according to the spatial relationship between grid cells at different time points, the collision analysis of the aircraft flying in the low-altitude airspace can be carried out, which helps to improve the flight safety of low-altitude airspace aircraft.

[0075] Embodiment III:

[0076] This embodiment provides a collision prevention method for the low-altitude aircraft. The difference between this embodiment and the second embodiment is that the second embodiment directly uses the grid cells where the instantaneous positions of the two aircraft are located at time point t for position analysis when analyzing the spatial relationship between the two aircraft at time point t. This embodiment further performs position analysis pairwise on the grid cells passed by the two aircraft from time point t - 1 to time point t, that is, calculates and the distance between is the closest distance between the central points of the grid cells passed by the two aircraft during the time period corresponding to the time points. Analyzing the collision state in this way is also more accurate.

[0077] In summary, the present invention first represents the flight path of the aircraft by obtaining the grid cells passed by the flight path of the aircraft to obtain a grid set, and then solves the technical problem of whether a collision occurs during the flight of the aircraft in the low-altitude airspace by judging the spatial relationship between the aircraft.

[0078] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for calculating the flight path of a low-altitude aircraft, characterized in that, The flight path calculation method includes the following steps: Step S1: Obtain the three-dimensional size data of the aircraft, and determine the earth grid level corresponding to the current aircraft according to the size of the earth grid unit at the earth grid level with the maximum size; Step S2: Obtain the flight path data of the aircraft to establish a path data set, where the flight path data is the earth space coordinate data at each time point; Step S3: Calculate the grid set of the current earth grid level passed by the flight path of the aircraft according to the path data set; The flight path calculation method further includes the following steps: Step S4: In three-dimensional space, display the grid set passed by the aircraft as the flight path of the aircraft; In step S1, the three-dimensional dimension data of the current aircraft is (l1, w1, h1), and the maximum dimension of the aircraft is dF1 = max(l1, w1, h1), where max is used to find the maximum value. If D(C levelF1+1 ) < dF1 ≤ D(C levelF1 ), it is considered that the corresponding Earth grid level of the current aircraft is levelF1, where C levelF1+1 is the next-level grid cell of C levelF1 , and D(C level ) represents the size length of the Earth grid cell C level at level level; In step S2, the established path data set is: ll1 = {(B 11 , L 11 , H 11 ), (B 12 , L 12 , H 12 ), …, (B 1n , L 1n , H 1n )}; There are earth space coordinate data of n time points in the set, and each earth space coordinate data is composed of longitude, latitude and altitude data; The specific process of step S3 is as follows: S31. Traverse each geospatial coordinate data in the path data set, and successively take out two adjacent points. For the two currently obtained points P i (B 1i , L 1i , H 1i ), P i+1 (B 1,i+1 , L 1,i+1 , H 1,i+1 ), where 1 ≤ i ≤ n - 1, and construct the line segment equation of the two points S32. According to the coordinate data of two points P i and P i+1 , determine whether the two points are in the same grid cell, and establish a grid set. The specific process is as follows:

321. Calculate the Earth grid cells at the level F1 where two points are located and where point P i the Earth grid cells at the level F1 where it is located is calculated as follows: Among them, is the ceiling function, N l , N b , N h respectively represent the serial number values of the earth grid cell in the longitude, latitude, and height directions in the earth grid at the current level; 322. Obtain the Earth grid cells according to the numbering method and The corresponding codes are respectively and And add the Earth grid cell to the grid set 323. If it indicates that the two points are within the same earth grid cell and then return to step S31 to traverse the next adjacent two points; if it indicates that point P i and point P i+1 are in different grid cells. With P i (B 1i , L 1i , H 1i ) as the center of the sphere and r = D(C levelF1 ) as the radius of the sphere, construct the sphere equation ⊙P i : ⊙P i :(x - B 1i ) 2 +(y - L 1i ) 2 +(z - H 1i ) 2 =r 2 Simultaneously solve the line segment equations and the sphere equation ⊙P i to find the intersection point P ∩j Then, using point P ∩j and point P i+1 construct the line segment equation Then, in the same way as step S32, determine whether point P ∩j and point P i+1 are within the same grid cell; If it is within the same grid cell, then point P ∩j The corresponding Earth grid cell is added to the grid set C ll1 If they are in different grid cells, then the sphere equation and the line segment equation are constructed again for judgment, and the grid set is continuously updated; S33: After the path data set traversal is completed, obtain the final grid set representing the flight path of the aircraft.

2. A collision prevention method for a low-altitude aircraft, characterized in that, The anti-collision method includes the low-altitude aircraft flight path calculation method as described in claim 1, and further includes the following steps: Step S5. For two aircrafts F1 and F2, obtain the position points P at the t moment from the grid sets of the corresponding flight paths F1,t and P F2,t where the grid cell C F1,t and C F2,t is located, and obtain the corresponding codes and Step S6. According to and 's relationship, as well as the distance between the center points of grid cells C F1,t and C F2,t , judge the spatial relationship R F1,t between grid cells C F2,t and C F1,F2 , including coincidence, inclusion, adjacency, and separation; Step S7. If the spatial relationship R F1,t between grid cells C F2,t and C F1,F2 is a coincidence or inclusion relationship, then the aircraft F1 and F2 will collide; if the relationship R F1,t between grid cells C F2,t and C F1,F2 is an adjacent relationship, then there is a risk of collision between the aircraft F1 and F2; if the relationship R F1,t between grid cells C F2,t and C F1,F2 is a separated relationship, then the aircraft F1 and F2 will not collide.

3. The anti-collision method for a low-altitude aircraft according to claim 2, characterized in that, The specific process of step S6 is as follows: S61. The layer where the aircraft F1 is located is levelF1, and the layer where the aircraft F2 is located is levelF2. Obtain the grid cells C F1,t and C F2,t . According to the earth grid division rule, obtain the central point coordinates corresponding to the grid cells C F1,t and C F2,t , which are PC F1,t (B F1,t , L F1,t , H F1,t ), PC F2,t (B F2,t , L F2,t , H F2,t ), and the side length and corner diagonal length of the grid cell. Among them, the side lengths of the grid cells C F1,t and C F2,t are d egde,F1 =D(C levelF1 ), d egde,F2 =D(C levelF2 ), and the corner diagonal lengths are respectively S62. According to the center point coordinates PC F1,t (B F1,t ,L F1,t ,H F1,t ), PC F2,t (B F2,t ,L F1,t ,H F2,t ), calculate the distance d F1,t between PC F2,t and PC F1,F1 : If then R F1,F1 is coincident; If and levelF1 = levelF2 and then R F1,F2 is adjacent; If and levelF1 = levelF2 and then R F1,F2 is adjacent; If and levelF1 = levelF2 and then R F1,F1 is separated; If and levelF1 > levelF2 and then R F1,F1 is inclusive, where means taking the first levelF2 bits of the encoding ; If and levelF1 > levelF2 and then R F1,F2 is adjacent; If and levelF1 > levelF2 and then R F1,F2 is adjacent; If and levelF1 > levelF2 and and then R 11,F2 is separated; If and levelF1 > levelF2 and and then R F1,F2 is separated.

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