WO2021082396A1

WO2021082396A1 - Unmanned aerial vehicle flight network modeling method based on low-altitude airspace restriction conditions

Info

Publication number: WO2021082396A1
Application number: PCT/CN2020/089918
Authority: WO
Inventors: 周龙; 汤淼
Original assignee: 南京智慧航空研究院有限公司
Priority date: 2019-11-01
Filing date: 2020-05-13
Publication date: 2021-05-06
Also published as: CN110782708A

Abstract

An unmanned aerial vehicle flight network modeling method based on low-altitude airspace restriction conditions, used for performing modeling description on restriction factors of a low-altitude airspace, constructing a flight raster network of an unmanned aerial vehicle, and providing technical support for an unmanned aerial vehicle flight path planning technology and an unmanned aerial vehicle conflict early warning, warning and conflict avoidance technology. The method comprises: firstly, constructing a terrain environment raster network, rasterizing terrain environment restrictions based on a digital elevation model, and establishing an elevation solving method of an arbitrary point in the raster network; secondly, constructing an airspace restriction environment raster network, and establishing topological relationships between track points and restriction airspaces, between flight segments and the restriction airspaces, and between the restriction airspaces, so as to implement unmanned aerial vehicle flight network modeling based on the low-altitude airspace restriction conditions.

Description

UAV flight network modeling method based on low-altitude airspace constraints

Technical field

The invention relates to the field of low-altitude airspace planning and management, and in particular to a drone flight network modeling method based on low-altitude airspace restriction conditions.

Background technique

With the reform and gradual opening of my country's low-altitude airspace and the rapid development of technology, the application range of drones has become wider and wider, and it has spread throughout the country and all walks of life. The demand for low-altitude airspace is increasing, and a series of The safety of low-altitude airspace has also attracted much attention. Making full use of limited low-altitude resources and ensuring the safety of low-altitude flight has become an important issue to be solved urgently.

Low-altitude airspace is the activity space of various aircraft, especially UAVs. It is an objective condition closely related to the operation of UAVs. How to model and describe the low-altitude airspace, such as UAV situation monitoring, path planning, hazard warnings, etc. It is of great significance. At present, the modeling and description of the low-altitude airspace is mainly accompanied by the establishment of a two-dimensional plane model or a three-dimensional space model when solving the flight path planning problem, and there is no systematic modeling and description of the low-altitude airspace according to the restrictions of the airspace and terrain.

Summary of the invention

In order to establish a complete and perfect UAV low-altitude operating environment, and effectively describe the limitations of low-altitude airspace and terrain, the present invention provides a UAV flight network modeling method based on the low-altitude airspace constraints, which is a useful tool for UAV management and control platforms. Build to provide theoretical support.

In order to achieve the above objectives, the technical solutions adopted by the present invention are as follows:

A UAV flight network modeling method based on low-altitude airspace restrictions. First, extract the operating environment characteristic data of the low-altitude airspace, including terrain environment, restricted areas, dangerous areas, no-fly zones, clear areas and other airspace environments (hereinafter referred to as restrictions) Airspace), and then model the terrain and restricted airspace separately, including the following steps:

Step 1: Extract the feature elements of the terrain environment, and rasterize the terrain environment based on the digital elevation model, that is, divide the space area into the same square grid unit;

Step 2: Convert the latitude and longitude of the grid vertex coordinates into three-dimensional space coordinates, that is, from the geodetic coordinate system to the world coordinate system;

Among them, N is the radius of curvature of the circle of the ellipsoid of the earth, e is the first eccentricity of the ellipsoid, a is the semi-major axis of the earth, b is the semi-minor axis, a=6378137±2(m), b=6356752.314 (m);

Step 3. Match its elevation value to the elevation value of the grid vertex based on the digital elevation model, and use the elevation interpolation method to calculate the elevation value of any point in the grid network. The specific steps are as follows:

(1) Determine the relationship between the selected interpolation point K and the vertices of the grid;

(2) When the interpolation point K is on the grid boundary, the nearest neighbor interpolation method is used to calculate the elevation of the interpolation point;

(3) When the interpolation point K is within the grid boundary, the bilinear interpolation method is used to calculate the height of the interpolation point.

Step 4: Extract the environmental characteristic elements of restricted airspace and establish an air restricted area information database;

Step 5. Construct a four-dimensional spatial element structure of the restricted airspace and rasterize the restricted airspace;

Step 6. Construct the topological network structure relationship between the track point and the restricted airspace. The specific steps are as follows:

(1) The track point a _i ∈Ω _j , this track point is in the restricted airspace Ω _j ;

(2) Track point

This track point is outside the restricted airspace Ω _j .

Step 7: Establish a topological network structure relationship between flight segments and restricted airspace. The specific steps are as follows:

(1) Flight segment

This flight segment does not intersect with the restricted airspace Ω _j;

(2) Flight segment

This flight segment intersects the _{restricted airspace Ω j.}

Step 8. Construct a topological network structure relationship between restricted airspace and restricted airspace. The specific steps are as follows:

(1) Restricted airspace

The airspace Ω _i and the airspace Ω _j do not intersect;

(2) Restricted airspace

The airspace Ω _i and the airspace Ω _j intersect.

Further, the digital elevation model described in step 1 is a grid structure spatial data model composed of the elevation values of divided regular grid points.

Further, the method for calculating the height of the interpolation point K using the nearest neighbor interpolation method described in step 3 is:

Further, the method for calculating the height of the interpolation point K using the bilinear interpolation method described in step 3 is:

dem _K = dem _A +(dem _B -dem _A )x _K +(dem _C -dem _A )y _K +(dem _A -dem _C +dem _D -dem _B )x _K y _K

Further, the four-dimensional space element described in step 5 is a space area that defines a horizontal boundary and a height boundary and the effective time range of the airspace.

The present invention has the following beneficial technical effects:

Aiming at the terrain restrictions and airspace restrictions in UAV flight path planning, a UAV flight network modeling method based on low-altitude airspace restrictions is established, which can systematically describe terrain and airspace environmental restrictions. The limiting factors are three-dimensionally rasterized, and the topological structure between track points, flight segments, and restricted airspace is constructed, which provides support for UAV flight path planning technology, UAV conflict early warning and conflict avoidance technology.

Description of the drawings

Figure 1 is a flow chart of UAV flight network modeling based on terrain and restricted airspace;

Figure 2 is a grid model diagram with elevation;

Figure 3 is a structural diagram of four-dimensional spatial elements in restricted airspace;

Figure 4 is a flow chart for constructing the topological relationship between track points and restricted airspace;

Figure 5 is a flow chart for constructing the topological relationship between flight segments and restricted airspace;

Figure 6 is a flow chart for constructing the topological relationship between restricted airspace and restricted airspace.

Detailed ways

In order to make the objectives and technical solutions of the invention clearer, the following further describes the invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments:

As shown in Figure 1, the method for modeling a drone flight network based on low-altitude airspace constraints provided by an embodiment of the present invention includes the following steps:

Step 1: Analyze the characteristic elements of the operating environment in the low-altitude airspace, including terrain environmental constraints and airspace environmental constraints; airspace environmental data can be obtained from the National Navigational Information Collection (NAIP);

Step 2: Extract the feature elements of the terrain environment from the geographic information system;

Step 3. As shown in Figure 2, rasterize the terrain environment based on the digital elevation model, that is, divide the space area into the same square grid cells;

Step 4: Extract the grid vertex coordinates according to the digital elevation model, and convert the latitude and longitude heights into three-dimensional space coordinates, that is, convert the geodetic coordinate system to the world coordinate system;

Step 5. Match the elevation value to the elevation value of the grid vertex based on the digital elevation model, and use the elevation interpolation method to calculate the elevation value of any point in the grid network:

(1) First extract the coordinates of the four vertices of the grid A (x _i , y _j , dem _A ), B (x _i , y _j+1 , dem _B ), C (x _i+1 , y _j , dem _C ) , D(x _i+1 , y _j+1 , dem _D ), and their elevation values are dem _A , dem _B , dem _C , and dem _{D respectively} ;

(2) When the interpolation point K is on the grid boundary, the nearest neighbor interpolation method is used to calculate the interpolation point elevation dem _K :

(3) When the interpolation point K is within the grid boundary, the bilinear interpolation method is used to calculate the interpolation point elevation dem _K :

Step 6. Extract the environmental characteristic elements of restricted airspace and establish an air restricted area information database;

Step 7. As shown in Figure 3, construct a four-dimensional spatial element structure of the restricted airspace, and rasterize the restricted airspace;

Step 8. As shown in Figure 4, construct the topological network structure relationship between the track point and the restricted airspace. The specific steps are as follows:

(1) Obtain the _{coordinates of the track point a i} and the restricted airspace Ω _j data, where Ω _j = {a ₁ , a ₂ ,..., a _n };

(2) The track point a _i ∈Ω _j , this track point is in the restricted airspace Ω _j ;

(3) Track point

This track point is outside the restricted airspace Ω _j .

Step 9. As shown in Figure 5, construct the topological network structure relationship between flight segments and restricted airspace. The specific steps are as follows:

(1) Obtain air segment A _i data and restricted airspace Ω _j data, where A _i = {a _m , a _m+1 ,..., a _k }, Ω _j = {a ₁ , a ₂ ,... , A _n };

(2) Flight segment

This flight segment does not intersect with the restricted airspace Ω _j;

(3) Flight segment

This flight segment intersects the _{restricted airspace Ω j.}

Step 10. As shown in Figure 6, construct the topological network structure relationship between restricted airspace and restricted airspace. The specific steps are as follows:

(1) Obtain restricted airspace Ω _i data and restricted airspace Ω _j data, where Ω _i = {a _p , a _p+1 ,..., a _q }, Ω _j = {a ₁ , a ₂ ,... , A _n };

(2) Restricted airspace

The airspace Ω _i and the airspace Ω _j do not intersect;

(3) Restricted airspace

The airspace Ω _i and the airspace Ω _j intersect.

The present invention establishes a UAV flight network modeling method based on low-altitude airspace restriction conditions. Aiming at the terrain restriction and airspace restriction issues in UAV flight path planning, the terrain environment and restricted airspace are respectively subjected to three-dimensional rasterization, Construct an elevation solution method for any point in the grid network, and construct the topological structure between track points, flight segments, and restricted airspace, so as to complete the modeling of the UAV's flight network limiting factors.

The above embodiments are only to illustrate the technical ideas of the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solutions of the present invention fall into the protection scope of the present invention.

Claims

An unmanned aerial vehicle flight network modeling method based on low-altitude airspace restriction conditions is characterized in that the low-altitude airspace restriction conditions include terrain environmental restrictions, restricted areas, dangerous areas, no-fly zones, clear areas and other airspace environmental restrictions. The described UAV flight network modeling method based on low-altitude airspace restrictions includes the following steps:

Step 1: Extract the feature elements of the terrain environment, and rasterize the terrain environment based on the digital elevation model, that is, divide the space area into the same square grid unit;

Step 2: Convert the latitude and longitude of the grid vertex coordinates into three-dimensional space coordinates, that is, from the geodetic coordinate system to the world coordinate system;

Step 3: Match the elevation value to the elevation value of the grid vertex based on the digital elevation model, and use the elevation interpolation method to calculate the elevation value of any point in the grid network;

Step 4. Extract the environmental characteristic elements of restricted airspace and establish an air restricted area information database;

Step 5. Construct a four-dimensional spatial element structure of the restricted airspace and rasterize the restricted airspace;

Step 6. Construct a topological network structure relationship between the track point and the restricted airspace;

Step 7: Establish a topological network structure relationship between flight segments and restricted airspace;

Step 8. Construct a topological network structure relationship between restricted airspace and restricted airspace.
The digital elevation model based on claim 1 matches its elevation value to the elevation value of the grid vertex, and uses the elevation interpolation method to calculate the elevation value of any point in the grid network, characterized in that the specific steps are as follows:

(1) First extract the coordinates of the four vertices of the grid A (x i , y j , dem A ), B (x i , y j+1 , dem B ), C (x i+1 , y j , dem C ) , D(x i+1 , y j+1 , dem D ), and their elevation values are dem A , dem B , dem C , and dem D respectively ;

(2) When the interpolation point K is on the grid boundary, the nearest neighbor interpolation method is used to calculate the interpolation point elevation dem K :

(3) When the interpolation point K is within the grid boundary, the bilinear interpolation method is used to calculate the interpolation point elevation dem K : dem K = dem A + (dem B- dem A ) x K + (dem C- dem A ) y K +(dem A -dem C +dem D -dem B )x K y K
The method for constructing a topological network structure relationship between a track point and a restricted airspace according to claim 1, wherein the specific steps are as follows:

(1) Obtain the coordinates of the track point a i and the restricted airspace Ω j data, where Ω j = {a 1 , a 2 ,..., a n };

(2) The track point a i ∈Ω j , this track point is in the restricted airspace Ω j ;

(3) Track point
This track point is outside the restricted airspace Ω j .
The method for constructing a topological network structure relationship between flight segments and restricted airspace according to claim 1, wherein the specific steps are as follows:

(1) Obtain air segment A i data and restricted airspace Ω j data, where A i ={a m , a m+1 ,..., a k ), Ω j ={a 1 , a 2 ,... , A n };

(2) Flight segment
This flight segment does not intersect with the restricted airspace Ω j;

(3) Flight segment
This flight segment intersects the restricted airspace Ω j.
The method for constructing a topological network structure relationship between restricted airspace and restricted airspace according to claim 1, wherein the specific steps are as follows:

(1) Obtain restricted airspace Ω i data and restricted airspace Ω j data, where Ω i = {a p , a p+1 ,..., a q }, Ω j = {a 1 , a 2 ,... , A n };

(2) Restricted airspace
The airspace Ω i and the airspace Ω j do not intersect;

(3) Restricted airspace
The airspace Ω i and the airspace Ω j intersect.