Low-altitude aircraft route setting method and device based on height layering and medium

Abstract

The invention discloses a low-altitude aircraft route setting method and equipment based on height layering, and the method comprises the steps: carrying out the layering of a low-altitude airspace model based on height, and obtaining a plurality of height layers; importing a digital three-dimensional base map into the layered low-altitude airspace model; respectively generating a corresponding two-dimensional connected graph for each height layer; carrying out route planning on the two-dimensional connected graph, and respectively generating corresponding two-dimensional routes; and generating a three-dimensional route according to the height layer and the two-dimensional route. According to the method, the complexity and difficulty of route design are reduced, the experience of ground vehicle automatic driving route planning can be conveniently applied to the field of route planning and route planning of low-altitude aircrafts, all height layers do not interfere with one another, and layered monitoring, layered scheduling and layered management are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of flight support for low-altitude aircraft, and particularly to a method, device, and medium for planning low-altitude aircraft routes based on altitude stratification. Background Art

[0002] With the gradual improvement of the performance of unmanned aerial vehicles, the demand for urban air transportation is increasing day by day, and the research on the planning of urban low-altitude air routes has become a hot issue. Urban air transportation is a new transportation system mainly based on vertical takeoff and landing and point-to-point transportation, suitable for rapid air transportation within cities and between cities. Urban low-altitude air routes are an important part of urban air transportation and are crucial for ensuring the safe, orderly, and efficient operation of urban low-altitude unmanned aerial vehicles.

[0003] Currently, there is no perfect standard and scheme for the planning of low-altitude aircraft routes. It is necessary to combine the low-altitude operation environment of cities and between cities, draw on the experience of urban ground transportation, and introduce advanced technical concepts of urban ground transportation into the planning of low-altitude aircraft routes. Low-altitude flight routes are three-dimensional, while urban ground transportation is two-dimensional, and certain improvements and adaptations are required for the application of advanced urban ground transportation technologies in the planning of low-altitude flight routes. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for planning low-altitude aircraft routes based on altitude stratification, which can, based on the idea of altitude stratification, reduce a digital three-dimensional base map to a two-dimensional connected graph, and can quickly apply a mature two-dimensional route planning algorithm for route design, reducing the complexity and difficulty of route design. Later, the research results of ground vehicle autonomous driving technology can be better introduced. At the same time, the idea of altitude stratification can arrange low-altitude aircraft of different mission types in different altitude layers, and each altitude layer does not interfere with each other, facilitating hierarchical monitoring, hierarchical scheduling, and hierarchical management.

[0005] The present invention also proposes a computer device and a computer-readable storage medium for implementing the above method for planning low-altitude aircraft routes based on altitude stratification.

[0006] According to the method for planning low-altitude aircraft routes based on altitude stratification in the first aspect embodiment of the present invention, it includes:

[0007] Stratify the low-altitude airspace model based on altitude to obtain a number of altitude layers;

[0008] Import a digital three-dimensional base map including terrain information into the stratified low-altitude airspace model;

[0009] Based on the digital three-dimensional base map, generate a corresponding two-dimensional connected graph for each altitude layer;

[0010] Use a two-dimensional route planning algorithm to perform route planning on the two-dimensional connectivity graph, and respectively generate corresponding two-dimensional routes;

[0011] Generate a three-dimensional route according to the altitude layer and the two-dimensional route.

[0012] According to some embodiments of the present invention, the hierarchical division of the low-altitude airspace model based on altitude to obtain several altitude layers includes:

[0013] Take the space between the minimum value and the maximum value of the restricted altitude of the low-altitude airspace as the low-altitude airspace model;

[0014] Perform hierarchical division of the low-altitude airspace model based on altitude to obtain several altitude layers, and maintain a safe altitude distance between adjacent altitude layers. The altitude layers are delimited according to the needs of the aircraft.

[0015] According to some embodiments of the present invention, the digital three-dimensional base map includes several grid-shaped three-dimensional coordinate points, which are used to represent the height and position of urban buildings and terrain.

[0016] According to some embodiments of the present invention, based on the digital three-dimensional base map, respectively generate corresponding two-dimensional connectivity graphs for each altitude layer, including:

[0017] Based on the terrain elevation data of the digital three-dimensional base map, respectively set connectivity areas and non-passable areas for each altitude layer;

[0018] Based on the population density and facility distribution of the digital three-dimensional base map, respectively set non-passable areas for each altitude layer;

[0019] Based on the non-passable areas and the connectivity areas, form the two-dimensional connectivity graphs of the corresponding altitude layers.

[0020] According to some embodiments of the present invention, based on the terrain elevation data of the digital three-dimensional base map, respectively set connectivity areas and non-passable areas for each altitude layer, including:

[0021] Check the elevation value of each three-dimensional coordinate point and the altitude of the altitude layer one by one. If the elevation value is higher than the altitude of the altitude layer by a safety margin, set the three-dimensional coordinate point as a connectivity area;

[0022] If the elevation value is not higher than the altitude of the altitude layer by a safety margin, set the three-dimensional coordinate point as a non-passable area.

[0023] According to some embodiments of the present invention, using a two-dimensional route planning algorithm to perform route planning on the two-dimensional connectivity graph and respectively generate corresponding two-dimensional routes, including:

[0024] Initial setup, setting several starting coordinates, several ending coordinates, a first matrix, and a second matrix; the first matrix includes: variable point position coordinates, estimated values, and path values; the second matrix includes: node positions and the positions of the child nodes of the nodes; wherein, the estimated value is used to represent the estimated cost of the best path from the variable point to the end point, and the path value is used to represent the actual cost from the starting point to the variable point;

[0025] Calculate the estimated value and the path value of the starting point to obtain the starting point estimated value and the starting point path value, and add the starting point coordinates, the starting point estimated value, and the starting point path value to the first matrix;

[0026] Find the point with the smallest estimated value in the first matrix, and set the point with the smallest estimated value as the current node;

[0027] If the current node is the end point, backtrack the path according to the second matrix and end the process. If the current node is not the end point, search for the child nodes of the current node;

[0028] Judge whether the child node is located in the connected area of the two-dimensional connected graph. If not, discard the child node;

[0029] Judge whether the child node is in the first matrix. If not, add the child node to the first matrix;

[0030] Calculate the path value from the current node to the child node to obtain the node path value;

[0031] If the node path value is not less than the original path value of the child node, discard the child node. If the node path value is less than the original path value of the child node, update the estimated value and the path value of the child node;

[0032] Save the current node as the parent node of the child node, save the parent node and the corresponding child node to the second matrix, and return to the step: find the point with the smallest estimated value in the first matrix, and set the point with the smallest estimated value as the current node.

[0033] According to some embodiments of the present invention, the backtracking the path according to the second matrix and ending the process includes:

[0034] Search in the second matrix, starting from the end point, and find the corresponding parent nodes until the starting point respectively to form the two-dimensional shipping route.

[0035] According to some embodiments of the present invention, the generating the three-dimensional shipping route according to the altitude layer and the two-dimensional shipping route includes:

[0036] Add the altitude of the corresponding altitude layer to the path node coordinate array of the two-dimensional flight path to form the three-dimensional flight path.

[0037] A computer device according to an embodiment of the second aspect of the present invention includes:

[0038] One or more processors;

[0039] A memory;

[0040] One or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the program is executed by the processor, it implements the steps of the method for planning a low-altitude aircraft flight path based on altitude stratification as described in any one of the above embodiments.

[0041] A computer-readable storage medium according to an embodiment of the third aspect of the present invention, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the method for planning a low-altitude aircraft flight path based on altitude stratification as described in any one of the above embodiments.

[0042] The method for planning a low-altitude aircraft flight path based on altitude stratification according to an embodiment of the present invention has at least the following beneficial effects: By using the idea of altitude stratification, the low-altitude airspace resources are divided into multiple altitude layers, and then a digital three-dimensional base map is introduced. Based on the terrain elevation data, no-fly zones, and threat zones of the digital three-dimensional base map, a two-dimensional connectivity map of each altitude layer is generated, so that the three-dimensional low-altitude airspace is decomposed into several two-dimensional plane regions. Subsequently, a mature two-dimensional flight path planning algorithm is used to plan the flight path for each two-dimensional plane region respectively. Finally, the planned two-dimensional flight path is combined with the corresponding altitude information to generate a three-dimensional flight path, thereby reducing the complexity and difficulty of flight path design. It can also better introduce the research results of ground vehicle autonomous driving technology and facilitate the application of the experience of ground vehicle autonomous driving route planning in the field of low-altitude aircraft path planning and flight path planning. At the same time, the method of stratifying the spatial resources of the low-altitude airspace by altitude can also arrange low-altitude aircraft of different mission types in different altitude layers, so that each altitude layer does not interfere with each other, facilitating hierarchical monitoring, hierarchical scheduling, and hierarchical management.

[0043] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The following further describes the present invention in conjunction with the drawings and embodiments, wherein:

[0045] Figure 1 Is the overall flowchart of the method for planning a low-altitude aircraft flight path based on altitude stratification according to an embodiment of the present invention;

[0046] Figure 2 This is the detailed flowchart of the two-dimensional route planning for the low-altitude aircraft route planning method based on altitude stratification according to the embodiments of the present invention;

[0047] Figure 3 This is the schematic diagram of altitude stratification for the low-altitude aircraft route planning method based on altitude stratification according to the embodiments of the present invention;

[0048] Figure 4 This is the schematic diagram of the two-dimensional connectivity graph for the low-altitude aircraft route planning method based on altitude stratification according to the embodiments of the present invention. Detailed implementation manners

[0049] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0050] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0051] In the description of the present invention, the meaning of several is more than one, and the meaning of multiple is more than two. Understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0052] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0053] In the description of the present invention, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0054] The following will Figures 1-4 , in detail, describe the method and device for planning low-altitude aircraft routes based on altitude stratification of the present invention.

[0055] Referring to Figure 1 and Figure 2 , the present invention proposes a method for planning low-altitude aircraft routes based on altitude stratification, including:

[0056] S100: Stratify the low-altitude airspace model based on altitude to obtain several altitude layers;

[0057] S200: Import a digital three-dimensional base map including terrain information into the stratified low-altitude airspace model;

[0058] S300: Generate a corresponding two-dimensional connectivity map for each altitude layer based on the digital three-dimensional base map;

[0059] S400: Use a two-dimensional route planning algorithm to plan routes for the two-dimensional connectivity map to generate corresponding two-dimensional routes respectively;

[0060] S500: Generate a three-dimensional route according to the altitude layer and the two-dimensional route.

[0061] Specifically, in this embodiment, the altitude stratification of the low-altitude airspace in step S100 is as follows: Divide the low-altitude airspace resources [h min , h max into N altitude layers {h1, h2, h3,......., h N}, h i ∈ [h min , h max , where h min is the minimum value of the restricted altitude of the low-altitude airspace, and h maxis the maximum value of the restricted altitude in the low-altitude airspace; the altitude levels are set considering the route requirements of low-altitude aircraft, arranging general aviation transport low-altitude aircraft, industry application low-altitude aircraft, and consumer application low-altitude aircraft from high to low; multiple altitude levels can be arranged for each type of low-altitude aircraft, delimited according to the requirements of low-altitude aircraft; the altitude difference between each altitude level needs to maintain a safe altitude distance, that is, the altitude difference between two adjacent altitude levels needs to exceed the altitude safety distance |h i+1 -h i |>h safe where h i+1 and h i are the altitudes of two adjacent altitude levels, and h safe is the required altitude safety distance. The altitude stratification schematic diagram is as shown in Figure 3 shown.

[0062] The introduction of the digital three-dimensional base map in step S200 is specifically as follows: According to the low-altitude airspace range, import the digital three-dimensional base map, which contains a series of position and altitude sequences, and is a series of grid-like three-dimensional coordinate points (XX, YY, HH), representing the heights of urban buildings and terrain heights. XX and YY represent the planar positions, and HH is the altitude, representing the heights of urban buildings and terrain heights. The mathematical expression form of the digital three-dimensional base map is

[0063] H = {h(x, y)|x = 1, 2,..., X max ; y = 1, 2,..., Y max};

[0064] where h(x, y) is the altitude value of the grid coordinate sampling point (x, y); X max and Y max are the scales of the map.

[0065] The generation of the two-dimensional connectivity map in step S300 is specifically as follows: For each altitude level h i , based on the terrain elevation data, no-fly zones, and threat zones, generate the two-dimensional connectivity map of this altitude level, which is carried out in the following two steps:

[0066] (1) Set the connectivity area based on the terrain elevation data: For each grid coordinate sampling point (x, y), check one by one its altitude value h(x, y) and the altitude of the altitude level h i , considering a certain safety margin. If its altitude value h(x, y) is higher than the altitude of the altitude level h i by a certain distance h0, that is, h(x, y) - h i > h0, then set this grid coordinate sampling point (x, y) as the connectivity area and set L(x, y) = 1, indicating passable; otherwise, set L(x, y) = 0, indicating non-passable;

[0067] (2) Set the connected area based on threats: Set the no-fly zone and threat area according to the ground population density and facility distribution, which are non-passable areas. For each grid coordinate sampling point (x, y), if it is outside the no-fly zone and threat area, set this grid coordinate sampling point (x, y) as the connected area, and set L(x, y) = 1, indicating passable; otherwise, set L(x, y) = 0, indicating non-passable.

[0068] Finally, generate a two-dimensional connected graph in the form as Figure 4 shown.

[0069] The two-dimensional route planning in step S400 is specifically as follows: Based on the two-dimensional connected graph, use a mature two-dimensional route planning algorithm for route planning. For example, the A* algorithm can be used for route planning. The steps are as follows:

[0070] Step 1, initialize the settings. Set the starting point as start = (xs, ys), and the ending point as goal = (xg, yg); Set the openlist and closelist lists to be empty. openlist = {x, y, a, g}, which is a four-column matrix. The first two columns x and y are the positions of this point, the third column a is the estimated value of this point, that is, the estimated cost of the best path from this point to the ending point, and the 4th column is the path value, that is, the actual cost from the starting point to this point; closelist = {xp, yp, xc, yc}, which is a four-column matrix. The first two columns are the node positions, and the last two columns are the positions of the child nodes of this node.

[0071] Step 2, calculate the estimated value a and the path value g of the starting point, and add the starting point to the openlist. The calculation formulas are as follows:

[0072]

[0073] g = 0;

[0074] Step 3, sort the third column of the openlist from smallest to largest, and find the node with the smallest a value in the openlist as the current node to be processed, called the current node T temp ;

[0075] Step 4, if the current node T temp is the ending point, end the search; otherwise, go to step 5;

[0076] Step 5, search for the child nodes of T temp , and obtain the child nodes of T temp according to the search direction. The search direction is 4 directions: forward, backward, left, and right. Search one step in each direction according to the search step size to obtain the adjacent nodes as the child nodes T temp of T child . The calculation formulas are as follows:

[0077] T child = T temp + dir * step

[0078] Where dir is the search direction, e.g., (0, 1) means searching to the right, and step is the step size.

[0079] Step 6, determine the connectivity of child node T child According to the 2D connectivity graph, if L(x child , y child ) = 1, then this child node is a connected area, and go to Step 7; otherwise, discard this child node.

[0080] Step 7, based on the position of T child , search in the first two columns of openlist. If T child is not in openlist, then add T child to openlist and set the path value g of T child to inf; otherwise, go to Step 8;

[0081] Step 8, calculate the path value g temp from T child to T child . The calculation formula is as follows:

[0082] g child = g temp + dis(T temp , T child );

[0083] Where g temp is the path value of T temp , and dis(T temp , T child ) is the distance from T temp to T child .

[0084] Step 9, judge the quality of the path value from T temp to T child . If the path value g temp from T child to T child is smaller than the originally saved path value g old of this child node, and the originally saved path value g old of this child node can be obtained from the fourth column of the corresponding child node in openlist, then the path from the current node to this child node is better, that is, g child < g old .

[0085] Step 10, if from T temp to T childIf the path is better, update the estimated value a and path value g of the child node; otherwise, discard the child node. The calculation formula is as follows:

[0086] g = g child

[0087] a = g child + heuristic(child, goal);

[0088] where heuristic(child, goal) = |x child - x goal | + |y child - y goal |.

[0089] Step 11, save T temp as the parent node of T child and save it together with T child to closelist. The first two columns save T temp and the last two columns save T child , then return to Step 3 for looping.

[0090] Step 12, search in closelist. Starting from the end point, find the corresponding parent node until the start point, which is the planned 2D route. The form is as follows:

[0091] P2 = {(x1, y1), (x2, y2),...(x m , y m )}.

[0092] The generation of the 3D route in Step S500 is specifically as follows: Combining the altitude layer h i , the 3D route is obtained. The form is as follows:

[0093] P3 = {(x1, y1, h i ), (x2, y2, h i ),...(x m , y m , h i )}.

[0094] By adopting the idea of hierarchical stratification based on altitude, the low-altitude airspace resources are divided into multiple altitude layers. Subsequently, a digital 3D base map is introduced, and based on the terrain elevation data, no-fly zones, and threat zones of the digital 3D base map, a 2D connectivity map of each altitude layer is generated, thereby decomposing the 3D low-altitude airspace into several 2D plane regions. Subsequently, a mature 2D route planning algorithm is used to perform route planning for each 2D plane region respectively. Finally, the planned 2D routes are combined with the corresponding altitude information to generate 3D routes, thus reducing the complexity and difficulty of route design. It can also better introduce the research results of ground vehicle autonomous driving technology and facilitate the application of the experience of ground vehicle autonomous driving route planning to the path planning and route planning fields of low-altitude aircraft. At the same time, the method of stratifying the spatial resources of the low-altitude airspace by altitude can also arrange low-altitude aircraft of different mission types in different altitude layers, making each altitude layer non-interfering with each other, facilitating hierarchical monitoring, hierarchical scheduling, and hierarchical management.

[0095] Referring to Figure 3 , further, in some embodiments of the present invention, step S100: Perform altitude-based stratification on the low-altitude airspace model to obtain several altitude layers, including:

[0096] 1.1 Consider the space between the minimum value of the low-altitude airspace restricted altitude and the maximum value of the low-altitude airspace restricted altitude as the low-altitude airspace model;

[0097] 1.2 Perform altitude-based stratification on the low-altitude airspace model to obtain several altitude layers, maintaining an altitude safety distance between adjacent altitude layers, and the altitude layers are delimited according to the needs of the aircraft.

[0098] Specifically, in this embodiment, the altitude stratification of step S100 is as follows: Divide the low-altitude airspace resources [h min , h max into N altitude layers {h1, h2, h3,......., h N}, h i ∈ [h min , h max , where h min is the minimum value of the low-altitude airspace restricted altitude, and h max is the maximum value of the low-altitude airspace restricted altitude; the setting of the altitude layers considers the route requirements of low-altitude aircraft, and arranges low-altitude aircraft for general aviation transportation, industry application, and consumer application from high to low; multiple altitude layers can be arranged for each type of low-altitude aircraft, delimited according to the needs of the low-altitude aircraft; the altitude difference between each altitude layer needs to maintain a safe altitude distance, that is, the altitude difference between adjacent two altitude layers needs to exceed the altitude safety distance |h i+1 - h i | > h safe Among them, hi+1 and h i are two adjacent height levels, and h safe is the required height safety distance. The schematic diagram of height stratification is as shown in Figure 3 . The method of height stratifying the airspace resources in the low altitude can also arrange low altitude aircraft of different mission types in different height levels, so that each height level does not interfere with each other, facilitating stratified monitoring, stratified scheduling, and stratified management.

[0099] Furthermore, in some embodiments of the present invention, the digital three-dimensional base map includes a number of grid-shaped three-dimensional coordinate points for characterizing the height and position of urban buildings and terrain.

[0100] Specifically, in this embodiment, the digital three-dimensional base map contains a series of position and altitude sequences, which are a series of grid-shaped three-dimensional coordinate points (XX, YY, HH), representing the height of urban buildings and terrain height. XX and YY represent the planar position, and HH is the elevation, representing the height of urban buildings and terrain height. The mathematical expression form of the digital three-dimensional base map is

[0101] H = {h(x, y)|x = 1, 2,..., X max ; y = 1, 2,..., Y max};

[0102] where h(x, y) is the elevation value of the grid coordinate sampling point (x, y); X max and Y max are the scales of the map.

[0103] Referring to Figure 4 , further, in some embodiments of the present invention, step S300: Based on the digital three-dimensional base map, generate a corresponding two-dimensional connectivity map for each height level, including:

[0104] 3.1 Based on the terrain elevation data of the digital three-dimensional base map, set the connectivity area and the non-passable area for each height level respectively;

[0105] 3.2 Based on the population density and facility distribution of the digital three-dimensional base map, set the non-passable area for each height level respectively;

[0106] 3.3 Based on the non-passable area and the connectivity area, form the two-dimensional connectivity map of the corresponding height level.

[0107] Specifically, in this embodiment, the generation of the two-dimensional connectivity map in step S300 is as follows: For each height level h i , based on the terrain elevation data, no-fly zone, and threat zone, generate the two-dimensional connectivity map of this height level, which is carried out in the following two steps:

[0108] (1) Set the connected area based on terrain elevation data: For each grid coordinate sampling point (x, y), check one by one its elevation value h(x, y) against the height of the height layer h i If, considering a certain safety margin, the elevation value h(x, y) is higher than the height of the height layer h i by a certain distance h0, that is, h(x, y) - h i > h0, then set the grid coordinate sampling point (x, y) as the connected area and set L(x, y) = 1, indicating passable; otherwise, set L(x, y) = 0, indicating impassable.

[0109] (2) Set the connected area based on threats: Set the no-fly zone and threat area according to the ground population density and facility distribution, which are impassable areas. For each grid coordinate sampling point (x, y), if it is outside the no-fly zone and threat area, then set the grid coordinate sampling point (x, y) as the connected area and set L(x, y) = 1, indicating passable; otherwise, set L(x, y) = 0, indicating impassable.

[0110] Finally, generate a two-dimensional connected graph in the form as Figure 4 shown.

[0111] Furthermore, in some embodiments of the present invention, step 3.1: Based on the terrain elevation data of the digital three-dimensional base map, set the connected area and impassable area for each height layer respectively, including:

[0112] 3.1.1 Check one by one the elevation value of each three-dimensional coordinate point against the height of the height layer;

[0113] 3.1.2 If the elevation value is higher than the height of the height layer by the safety margin, then set the three-dimensional coordinate point as the connected area;

[0114] 3.1.3 If the elevation value is not higher than the height of the height layer by the safety margin, then set the three-dimensional coordinate point as the impassable area. Specifically, in this embodiment, step 3.1 is to set the connected area based on the terrain elevation data: For each grid coordinate sampling point (x, y), check one by one its elevation value h(x, y) against the height of the height layer h i If, considering a certain safety margin, the elevation value h(x, y) is higher than the height of the height layer h i by a certain distance h0, that is, h(x, y) - h i > h0, then set the grid coordinate sampling point (x, y) as the connected area and set L(x, y) = 1, indicating passable; otherwise, set L(x, y) = 0, indicating impassable.

[0115] Further, in some embodiments of the present invention, step S400: Use a two-dimensional route planning algorithm to perform route planning on the two-dimensional connected graph, and generate corresponding two-dimensional routes respectively, including:

[0116] 4.1 Initialization settings, set several starting point coordinates start, several ending point coordinates goal, a first matrix openlist and a second matrix closelist; the first matrix includes: variable point position coordinates, estimated values, and path values; the second matrix includes: node positions and the positions of the child nodes of the nodes; among them, the estimated value is used to represent the estimated cost of the best path from the variable point to the end point, and the path value is used to represent the actual cost from the starting point to the variable point;

[0117] 4.2 Calculate the estimated value and path value of the starting point to obtain the starting point estimated value and the starting point path value, and add the starting point coordinates, the starting point estimated value, and the starting point path value to the first matrix;

[0118] 4.3 Find the point with the smallest estimated value in the first matrix, and set the point with the smallest estimated value as the current node;

[0119] 4.4 If the current node is the end point, backtrack the path according to the second matrix and end the process. If the current node is not the end point, search for the child nodes of the current node;

[0120] 4.5 Determine whether the child node is located in the connected area of the two-dimensional connected graph. If not, discard the child node;

[0121] 4.6 Determine whether the child node is in the first matrix. If not, add the child node to the first matrix;

[0122] 4.7 Calculate the path value from the current node to the child node to obtain the node path value;

[0123] 4.8 If the node path value is not less than the original path value of the child node, discard the child node. If the node path value is less than the original path value of the child node, update the estimated value and path value of the child node;

[0124] 4.9 Save the current node as the parent node of the child node, save the parent node and the corresponding child node to the second matrix, and return to the step: Find the point with the smallest estimated value in the first matrix, and set the point with the smallest estimated value as the current node.

[0125] Specifically, in this embodiment, the two-dimensional route planning in step S400 is specifically as follows: Based on the two-dimensional connected graph, use a mature two-dimensional route planning algorithm for route planning. For example, the A* algorithm can be used for route planning, and the steps are as follows:

[0126] Step 1, initialization settings, set the starting point to start = (xs, ys), the end point to goal = (xg, yg); set the openlist and closelist lists to be empty, openlist = {x, y, a, g}, a four-column matrix, where the first two columns x, y are the position of the point, the third column a is the estimated value of the point, that is, the estimated cost of the best path from the point to the end point, and the fourth column is the path value, that is, the actual cost from the starting point to the point; closelist = {xp, yp, xc, yc}, a four-column matrix, the first two columns are the node positions, and the last two columns are the child node positions of the node. Among them, openlist is the first matrix and closelist is the second matrix.

[0127] Step 2, calculate the estimated value a of the starting point and the path value g, add the starting point to the openlist, and the calculation formula is as follows:

[0128]

[0129] g=0.

[0130] Step 3: Sort the third column of openlist from small to large, and find the node with the smallest a value in openlist as the node to be processed, called the current node T temp ;

[0131] Step 4: If the current node T temp If it is the end point, the search ends and goes to step 12, otherwise go to step 5;

[0132] Step 5, search for T temp The child nodes of T are obtained according to the search direction. temp The search direction is 4 directions: front, back, left, and right. According to the search step length, search one step in each direction to obtain the adjacent node as T temp Child node T child , the calculation formula is as follows:

[0133] T child =T temp +dir*step;

[0134] Among them, dir is the search direction, such as (0,1) means searching to the right, and step is the step size.

[0135] Step 6: Determine the child node T child Connectivity, according to the two-dimensional connectivity graph, if L(x child ,y child )=1, the child node is a connected area, then go to step 7, otherwise, discard the child node.

[0136] Step 7: According to Tchild Position, search in the first two columns of the openlist. If T child is not in the openlist, then add T child to the openlist and set the path value g of T child to inf. Otherwise, go to step 8.

[0137] Step 8, calculate the path value g from T temp to T child . The calculation formula is as follows: child g

[0138] = g child + dis(T temp , T temp , T child );

[0139] where g temp is the path value of T temp , and dis(T temp , T child ) is the distance from T temp to T child .

[0140] Step 9, judge the quality of the path value from T temp to T child . If the path value g from T temp to T child is smaller than the previously saved path value g of this child node, and the previously saved path value g of this child node can be obtained from the fourth column of the corresponding child node in the openlist, then the path from the current node to this child node is better, that is, g child < g old . old child old < g old .

[0141] Step 10, if the path from T temp to T child is better, then update the estimated value a and path value g of this child node. Otherwise, discard this child node. The calculation formula is as follows:

[0142] g = g child

[0143] a = g child + heuristic(child, goal);

[0144] where heuristic(child, goal) = |x child - x goal | + |y child - y goal |.

[0145] Step 11, save T temp As the parent node of T child and save it together with T child to closelsit. The first two columns save T temp and the last two columns save T child , then return to Step 3 for looping.

[0146] Step 12, search in closelist, starting from the end point, find the corresponding parent node until the starting point, which is the planned two-dimensional flight path. The form is as follows:

[0147] P2 = {(x1, y1), (x2, y2),...(x m , y m )};

[0148] By adopting a mature two-dimensional flight path planning algorithm to perform flight path planning for each two-dimensional plane area respectively, the complexity and difficulty of flight path design are reduced, and the research results of ground vehicle autonomous driving technology can be better introduced, facilitating the application of the experience of ground vehicle autonomous driving route planning (i.e., plane route planning) to the field of low-altitude aircraft path planning and flight path planning.

[0149] Furthermore, in some embodiments of the present invention, step 4.4 of backtracking the path according to the second matrix and ending the process includes:

[0150] Search in the second matrix, starting from the end point, find the corresponding parent node until the starting point respectively to form a two-dimensional flight path.

[0151] Specifically, in this embodiment, step 4.4 is specifically: search in closelist, starting from the end point, find the corresponding parent node until the starting point, which is the planned two-dimensional flight path, that is, Step 12. The form is as follows:

[0152] P2 = {(x1, y1), (x2, y2),...(x m , y m )}.

[0153] Furthermore, in some embodiments of the present invention, step S500: generating a three-dimensional flight path according to the altitude layer and the two-dimensional flight path includes:

[0154] Add the altitude of the corresponding altitude layer to the path node coordinate array of the two-dimensional flight path to form a three-dimensional flight path.

[0155] Specifically, in this embodiment, the generation of the three-dimensional flight path in step S500 is specifically: combining the altitude layer h i , to obtain the three-dimensional flight path, the form is as follows:

[0156] P3 = {(x1, y1, h i ), (x2, y2, h i ),...(x m , y m , h i )}。

[0157] The present invention also provides a computer device, comprising:

[0158] One or more processors;

[0159] A memory;

[0160] One or more programs, wherein one or more programs are stored in the memory and configured to be executed by one or more processors, and when the programs are executed by the processors, the steps of the method for planning the flight path of a low-altitude aircraft based on altitude stratification as described in any one of the above embodiments are implemented.

[0161] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above embodiments can be completed by hardware or by a program instructing relevant hardware. The program can be stored in a computer-readable storage medium. In the context of the present invention, the computer-readable medium can be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media include non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital tapes or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs), etc. The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to the processors or controllers of general-purpose computers, special-purpose computers, or other programmable data processing devices, such that when the program codes are executed by the processors or controllers, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program codes can be executed entirely on the machine, partially on the machine, executed as an independent software package partially on the machine and partially on a remote machine, or executed entirely on a remote machine or server.

[0162] In addition, although the operations are depicted in a particular order, this should be understood as requiring that the operations be performed in the particular order shown or in sequential order, or that all of the illustrated operations be performed to achieve the desired result. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of the present invention. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, the various features that are described in the context of a single implementation may also be implemented separately or in any suitable subcombination in multiple implementations.

[0163] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method for planning a low-altitude aircraft route based on a high-level hierarchy as described in any one of the foregoing embodiments are implemented. The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made without departing from the spirit of the present invention within the knowledge of those of ordinary skill in the art to which the present invention pertains. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for planning the flight route of a low-altitude aircraft based on altitude stratification, characterized in that, Including: Performing altitude-based stratification on the low-altitude airspace model to obtain a number of altitude layers; Importing a digital 3D base map including terrain information into the stratified low-altitude airspace model; Generating corresponding 2D connectivity maps for each of the altitude layers based on the digital 3D base map; Performing route planning on the 2D connectivity maps using a 2D route planning algorithm to generate corresponding 2D routes respectively; Generating a 3D route based on the altitude layer and the 2D route.

2. The method for planning low-altitude aircraft routes based on altitude stratification according to claim 1, wherein The performing altitude-based stratification on the low-altitude airspace model to obtain a number of altitude layers includes: Taking the space between the minimum and maximum restricted altitudes of the low-altitude airspace as the low-altitude airspace model; Performing altitude-based stratification on the low-altitude airspace model to obtain a number of the altitude layers, maintaining an altitude safety distance between adjacent altitude layers, and the altitude layers being delimited according to the requirements of the aircraft.

3. The method for planning the flight route of a low-altitude aircraft based on altitude stratification according to claim 1, characterized in that The digital 3D base map includes a number of grid-based 3D coordinate points for characterizing the heights and positions of urban buildings and terrain.

4. The method for planning the flight route of a low-altitude aircraft based on altitude stratification according to claim 3, characterized in that, The generating corresponding 2D connectivity maps for each of the altitude layers based on the digital 3D base map includes: Based on the terrain elevation data of the digital 3D base map, setting connectivity areas and non-passable areas for each of the altitude layers respectively; Based on the population density and facility distribution of the digital 3D base map, setting non-passable areas for each of the altitude layers respectively; Forming the 2D connectivity maps of the corresponding altitude layers based on the non-passable areas and the connectivity areas.

5. The method for planning the flight route of a low-altitude aircraft based on altitude stratification according to claim 4, characterized in that, The setting connectivity areas and non-passable areas for each of the altitude layers based on the terrain elevation data of the digital 3D base map includes: Checking the elevation value of each of the 3D coordinate points and the altitude of the altitude layer one by one; If the elevation value is higher than the altitude of the altitude layer by a safety margin, setting the 3D coordinate point as a connectivity area; If the elevation value is higher than the altitude of the altitude layer but not by a safety margin, setting the 3D coordinate point as a non-passable area.

6. The method for delineating the flight route of a low-altitude aircraft based on altitude stratification according to claim 1, wherein The performing route planning on the 2D connectivity maps using a 2D route planning algorithm to generate corresponding 2D routes respectively includes: Initial setting, setting a number of starting coordinates, a number of ending coordinates, a first matrix and a second matrix; the first matrix includes: variable point position coordinates, estimated values, path values; the second matrix includes: node positions and the sub-node positions of the nodes; wherein, the estimated value is used to represent the estimated cost of the best path from the variable point to the end point, and the path value is used to represent the actual cost from the starting point to the variable point; Calculating the estimated value and the path value of the starting point to obtain a starting point estimated value and a starting point path value, and adding the starting point coordinates, the starting point estimated value and the starting point path value to the first matrix; Finding the point with the smallest estimated value in the first matrix and setting the point with the smallest estimated value as the current node; If the current node is the end point, backtracking the path according to the second matrix and ending the process, if the current node is not the end point, searching for the sub-nodes of the current node; Determine whether the child node is located in the connected area of the two-dimensional connected graph. If not, discard the child node; Determine whether the child node is in the first matrix. If not, add the child node to the first matrix; Calculate the path value from the current node to the child node to obtain the node path value; If the node path value is not less than the original path value of the child node, discard the child node. If the node path value is less than the original path value of the child node, update the estimated value and path value of the child node; Save the current node as the parent node of the child node, save the parent node and the corresponding child node to the second matrix, and return to the step: find the point with the smallest estimated value in the first matrix and set the point with the smallest estimated value as the current node.

7. The method for planning the flight route of a low-altitude aircraft based on altitude stratification according to claim 6, characterized in that The step of backtracking the path according to the second matrix and ending the process includes: Search in the second matrix, starting from the end point, and find the corresponding parent nodes until the start point respectively to form the two-dimensional flight path.

8. The method for designing the flight route of a low-altitude aircraft based on altitude stratification according to claim 6, characterized in that, The step of generating a three-dimensional flight path according to the altitude layer and the two-dimensional flight path includes: Add the altitude of the corresponding altitude layer to the path node coordinate array of the two-dimensional flight path to form the three-dimensional flight path.

9. A computer device, characterized in that, Comprising: One or more processors; A memory; One or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors. When the program is executed by the processor, the steps of the method for planning a low-altitude aircraft flight path based on altitude stratification according to any one of claims 1-8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the method for planning a low-altitude aircraft flight path based on altitude stratification according to any one of claims 1-8 are implemented.

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