CN111435256A - Automatic terrain evasion method for aircraft based on grid map - Google Patents
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Abstract
The invention discloses an automatic terrain evasion method for an aircraft based on a grid map, which comprises the steps of firstly obtaining grid digital terrain data of a flight area based on an initial position and a target position of the aircraft, carrying out binarization processing on the grid digital terrain data based on the current flight height of the aircraft to generate terrain obstacle data of the flight area, then selecting a latest predicted position with an optimal grid from four neighborhoods of the current position of the aircraft based on an optimized theory and method, gradually iterating until the target position is reached, and finally sequentially extracting grid coordinates of all predicted positions from the current position to the target position to generate a terrain evasion path, so that the terrain penetration technology in a strong and complex terrain environment is researched, the terrain evasion capability of the aircraft is improved, and the operational efficiency of the aircraft is enhanced.
Description
Technical Field
The invention relates to the technical field of aviation control, in particular to technologies of terrain following, terrain avoidance, threat avoidance and the like related to a digital terrain database-based near-ground warning device widely applied to an aircraft, wherein the system comprises specific products of avionics devices such as an aircraft near-ground warning device, a near-ground collision avoidance system, a terrain prompting and warning system, an integrated environment monitoring system and the like.
Background
The flight path planning of the aircraft refers to finding the optimal motion track of the aircraft from an initial point to a target point under a specific constraint condition. The flight path planning of the military aircraft is a new generation low-altitude penetration technology for realizing the purposes of terrain following, terrain avoiding and threat avoidance flying, and aims to plan the penetration track of the aircraft with the maximum survival probability by utilizing information such as terrain, enemy conditions and the like. In modern war with increasingly perfect air defense technology, flight path planning is an effective means for improving the operational efficiency of aircrafts and implementing remote accurate attack. In addition, the international situation in the southwest region of China is complex, and the terrain features are various, so that the terrain penetration technology research in a complex terrain environment needs to be enhanced urgently, the terrain evasive capacity of the aircraft is improved, and the combat efficiency of the aircraft is enhanced.
The digital terrain data is regular gridding data of surface terrain and landform, and the data is organized and stored mainly in a grid data mode of regular grids. The digital terrain data is an indispensable important component of a near-earth warning system, and meanwhile, the digital terrain data is also important basic data of terrain following and terrain avoidance. For the research of the terrain avoidance problem, many scholars at home and abroad have proposed different solutions, but the existing terrain avoidance algorithm has higher time complexity and slower convergence speed, is not suitable for track planning under complex battlefield environments, and is difficult to realize the real-time requirement of a terrain track path. Therefore, a new terrain evasion algorithm needs to be provided urgently, the terrain evasion capability of the aircraft is improved, and the combat effectiveness of the aircraft is enhanced.
Disclosure of Invention
The invention discloses an automatic terrain evasion method for an aircraft based on a grid map, which comprises the steps of firstly obtaining grid digital terrain data of a flight area based on an initial position and a target position of the aircraft, carrying out binarization processing on the grid digital terrain data based on the current flight height of the aircraft to generate terrain obstacle data of the flight area, then selecting a latest predicted position with an optimal grid from four neighborhoods of the current position of the aircraft based on an optimized theory and method, gradually iterating until the target position is reached, and finally sequentially extracting grid coordinates of all predicted positions from the current position to the target position to generate a terrain evasion path, so that the terrain penetration technology in a strong and complex terrain environment is researched, the terrain evasion capability of the aircraft is improved, and the operational efficiency of the aircraft is enhanced.
The invention provides an automatic terrain evasion method for an aircraft based on a grid map, which is characterized by comprising the following steps of:
step A: extracting digital terrain data of a flight area based on the starting position and the target position of the aircraft;
and B: and performing binarization processing on the digital terrain data of the flight area based on the current flight altitude of the aircraft, and extracting the terrain obstacle data of the flight area.
And C: selecting a neighborhood grid of the current position from the data of the terrain obstacles, the existing predicted position, the target position information and the like according to the current position of the aircraft;
step D: respectively calculating the distance between each neighborhood grid and the initial position and the target position, and then calculating the target value of the neighborhood grid;
step E: selecting the grid with the minimum target value from all the neighborhood grids as a new prediction position;
step H: repeating the steps C-E until the new predicted position is the target position;
step G: and sequentially extracting coordinates of all predicted positions between the current position and the target position to generate a terrain evasion path.
And B, calculating the range of the flight area according to the current position and the target position of the aircraft by using the digital terrain data of the flight area in the step A, performing mosaic processing on the terrain data of the flight area, extracting the digital terrain data of the flight area, and providing basic data for a terrain evasion algorithm.
The terrain obstacle data in the step B is mainly used for positioning the terrain obstacle and searching the predicted position, the basic principle is that the current flight altitude of the aircraft is utilized to carry out binarization processing on the digital terrain data in the flight area, if the terrain altitude is larger than the current flight altitude, the digital terrain data is judged to be the terrain obstacle, the grid value is assigned to be 1, otherwise, the digital terrain data is judged to be the non-terrain obstacle, and the grid value is assigned to be 0.
In the step C, the neighborhood grid is selected by mainly considering information of four neighborhood grids around the current position, terrain obstacles, the existing predicted position, the target position and the like, and the main principle is as follows:
a, if a neighborhood grid of the current position contains a terrain obstacle, the neighborhood grid is not selected;
b, if the neighborhood grid of the current position contains the existing predicted position, the neighborhood grid is not selected;
c, if no suitable neighborhood grid exists in the current position or the number of suitable neighborhood grids in the four neighborhoods of the current position is 0, identifying the current grid as an invalid grid, returning to the last predicted position of the current position, and restarting the selection of the neighborhood grids;
d, if the neighborhood grid of the current position contains the target position grid, ending the terrain avoidance algorithm;
the target value f (x, y) of the neighborhood grid in step C is mainly calculated by the following formula:
f(x,y)＝g(x,y)+s(x,y)
wherein g (x, y) is the distance between the neighborhood grid and the starting position, and can be obtained by adding 1 to the distance between the last predicted position of the current grid position and the starting position through an iterative algorithm; s (x, y) is a distance between the current grid position and the target grid position, and can be obtained approximately by using the mahalanobis distance, and a specific calculation formula is as follows:
s(x,y)＝abs(x-xs)+abs(y-ys)
where x, y are the row and column numbers of the current grid, xs,ysThe target value of the neighborhood grid can be obtained based on the distance between the neighborhood grid and the initial position and the target position;
and E, calculating a new predicted position in the step E, wherein an optimal grid is mainly selected from the neighborhood grids of the current grid, and the basic principle of the optimal grid is the grid with the smallest target value in the neighborhood grids. However, if the target values of two neighboring grids are the same, the grid with the smallest included angle between the target position and the starting position is selected as a new prediction grid.
Step H is to repeat the processes from step C to step E on the basis of the new predicted position until the neighborhood grid of the new predicted position contains the target position, and then the iteration process is ended;
and G, sequentially extracting the row numbers and the column numbers of all predicted positions from the starting position to the target position on the basis of finishing the terrain avoidance algorithm to finish the generation of the terrain avoidance path.
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FIG. 1 illustrates a technical flow diagram of a grid map based automatic terrain avoidance technique for an aircraft
FIG. 2 illustrates a schematic diagram of an aircraft automatic terrain avoidance technique and verification results
Detailed Description
The invention discloses an automatic terrain evasion method for an aircraft based on a grid map, which comprises the steps of firstly obtaining grid digital terrain data of a flight area based on an initial position and a target position of the aircraft, carrying out binarization processing on the grid digital terrain data based on the current flight height of the aircraft to generate terrain obstacle data of the flight area, then selecting a latest predicted position with an optimal grid from four neighborhoods of the current position of the aircraft based on an optimized theory and method, gradually iterating until the target position is reached, and finally sequentially extracting grid coordinates of all predicted positions from the current position to the target position to generate a terrain evasion path, so that the terrain penetration technology in a strong and complex terrain environment is researched, the terrain evasion capability of the aircraft is improved, and the operational efficiency of the aircraft is enhanced.
The invention provides an automatic terrain evasion method for an aircraft based on a grid map, which is characterized by comprising the following steps of:
step A: extracting digital terrain data of a flight area based on the starting position and the target position of the aircraft;
and B: and performing binarization processing on the digital terrain data of the flight area based on the current flight altitude of the aircraft, and extracting the terrain obstacle data of the flight area.
And C: selecting a neighborhood grid of the current position from the data of the terrain obstacles, the existing predicted position, the target position information and the like according to the current position of the aircraft;
step D: respectively calculating the distance between each neighborhood grid and the initial position and the target position, and then calculating the target value of the neighborhood grid;
step E: selecting the grid with the minimum target value from all the neighborhood grids as a new prediction position;
step H: repeating the steps C to E until the new predicted position is the target position;
step G: and sequentially extracting coordinates of all predicted positions between the current position and the target position to generate a terrain evasion path.
And B, calculating the range of the flight area according to the current position and the target position of the aircraft by using the digital terrain data of the flight area in the step A, performing mosaic processing on the terrain data of the flight area, extracting the digital terrain data of the flight area, and providing basic data for a terrain evasion algorithm.
The terrain obstacle data in the step B is mainly used for positioning the terrain obstacle and searching the predicted position, the basic principle is that the current flight altitude of the aircraft is utilized to carry out binarization processing on the digital terrain data in the flight area, if the terrain altitude is larger than the current flight altitude, the digital terrain data is judged to be the terrain obstacle, the grid value is assigned to be 1, otherwise, the digital terrain data is judged to be the non-terrain obstacle, and the grid value is assigned to be 0.
In the step C, the neighborhood grid is selected by mainly considering information of four neighborhood grids around the current position, terrain obstacles, the existing predicted position, the target position and the like, and the main principle is as follows:
a, if a neighborhood grid of the current position contains a terrain obstacle, the neighborhood grid is not selected;
b, if the neighborhood grid of the current position contains the existing predicted position, the neighborhood grid is not selected;
c, if no suitable neighborhood grid exists in the current position or the number of suitable neighborhood grids in the four neighborhoods of the current position is 0, identifying the current grid as an invalid grid, returning to the last predicted position of the current position, and restarting the selection of the neighborhood grids;
d, if the neighborhood grid of the current position contains the target position grid, ending the terrain avoidance algorithm;
the target value f (x, y) of the neighborhood grid in step C is mainly calculated by the following formula:
f(x,y)＝g(x,y)+s(x,y)
wherein g (x, y) is the distance between the neighborhood grid and the starting position, and can be obtained by adding 1 to the distance between the last predicted position of the current grid position and the starting position through an iterative algorithm; s (x, y) is a distance between the current grid position and the target grid position, and can be obtained approximately by using the mahalanobis distance, and a specific calculation formula is as follows:
s(x,y)＝abs(x-xs)+abs(y-ys)
where x, y are the row and column numbers of the current grid, xs,ysThe target value of the neighborhood grid can be obtained based on the distance between the neighborhood grid and the initial position and the target position;
and E, calculating a new predicted position in the step E, wherein an optimal grid is mainly selected from the neighborhood grids of the current grid, and the basic principle of the optimal grid is the grid with the smallest target value in the neighborhood grids. However, if the target values of two neighboring grids are the same, the grid with the smallest included angle between the target position and the starting position is selected as a new prediction grid.
Step H is to repeat the processes from step C to step E on the basis of the new predicted position until the neighborhood grid of the new predicted position contains the target position, and then the iteration process is ended;
and G, sequentially extracting the row numbers and the column numbers of all predicted positions from the starting position to the target position on the basis of finishing the terrain avoidance algorithm to finish the generation of the terrain avoidance path.
The using method comprises the following steps: and packaging an aircraft automatic terrain avoidance technology software module based on a grid map, and embedding the software module into a main program of an aircraft automatic near-ground collision avoidance system or a terrain avoidance main program.
The above description is only intended to represent the embodiments of the present invention, and the description is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (8)
1. An automatic terrain evasion method for an aircraft based on a grid map is characterized by comprising the following steps,
a, extracting digital terrain data of a flight area based on an initial position and a target position of an aircraft;
b, performing binarization processing on the digital terrain data of the flight area based on the current flight altitude of the aircraft, and extracting terrain obstacle data of the flight area;
c, selecting a neighborhood grid of the current position from the terrain obstacle data, the existing predicted position, the target position information and other data according to the current position of the aircraft;
step D, respectively calculating the distance between each neighborhood grid and the initial position and the target position, and then calculating the target value of the neighborhood grid;
step E, selecting the grid with the minimum target value from all the neighborhood grids as a new prediction position;
step F, repeating the step C to the step E until the new predicted position is the target position; and the number of the first and second groups,
and G, sequentially extracting the coordinates of all predicted positions between the current position and the target position to generate a terrain evasion path.
2. The method as claimed in claim 1, wherein the digital terrain data of the flight area in step a is used to calculate the range of the flight area according to the current position and the target position of the aircraft, and the digital terrain data of the flight area is subjected to mosaic processing to extract the digital terrain data of the flight area and provide basic data for a terrain avoidance algorithm.
3. The method as claimed in claim 1, wherein the terrain obstacle data in step B is mainly used for locating a terrain obstacle and searching for a predicted position, and the basic principle is to perform binarization processing on the digital terrain data in the flight area by using the current flight altitude of the aircraft, and if the terrain altitude is greater than the current flight altitude, the terrain obstacle is determined, the grid value is assigned to 1, otherwise, the terrain obstacle is determined to be a non-terrain obstacle, and the grid value is assigned to 0.
4. The method for avoiding the automatic terrain of the aircraft based on the grid map as claimed in claim 1, wherein the selection of the neighborhood grid in the step C mainly takes into account information such as a four neighborhood grid around a current position, terrain obstacles, an existing predicted position and a target position to select the neighborhood grid, and the main principle is as follows:
a, if a neighborhood grid of the current position contains a terrain obstacle, the neighborhood grid is not selected;
b, if the neighborhood grid of the current position contains the existing predicted position, the neighborhood grid is not selected;
c, if no suitable neighborhood grid exists in the current position or the number of suitable neighborhood grids in four adjacent domains of the current position is 0, identifying the current grid as an invalid grid, returning to the last predicted position of the current position, and restarting the selection of the neighborhood grids;
and d, if the neighborhood grid of the current position contains the target position grid, ending the terrain avoidance algorithm.
5. The grid map-based aircraft automatic terrain avoidance method of claim 1, wherein the target value f (x, y) of the neighborhood grid in step D is mainly calculated by the following formula:
f(x,y)＝g(x,y)+s(x,y)
wherein g (x, y) is the distance between the neighborhood grid and the starting position, and can be obtained by adding 1 to the distance between the last predicted position of the current grid position and the starting position through an iterative algorithm; s (x, y) is a distance between the current grid position and the target grid position, and can be obtained approximately by using the mahalanobis distance, and a specific calculation formula is as follows:
s(x,y)＝abs(x-xs)+abs(y-ys)
where x, y are the row and column numbers of the current grid, xs,ysFor the row number of the target grid position, the target value of the neighborhood grid can be obtained based on the distance between the neighborhood grid and the starting position and the target position.
6. The method for automatically avoiding the terrain of the aircraft based on the grid map as claimed in claim 1, wherein the calculation of the new predicted position in the step E is mainly to select an optimal grid from the neighborhood grids of the current grid, and the basic principle is the grid with the smallest target value in the neighborhood grids. However, if the target values of two neighboring grids are the same, the grid with the smallest included angle between the target position and the starting position is selected as a new prediction grid.
7. The method for automatically avoiding the terrain of the aircraft based on the grid map as claimed in claim 1, wherein the step F is to repeat the processes from the step C to the step E based on a new predicted position until a neighborhood grid of the new predicted position contains a target position, and then the iterative process is ended.
8. The method as claimed in claim 1, wherein the terrain evasion path in step G is generated by sequentially extracting the rank numbers of all predicted positions from the starting position to the target position on the basis of the completion of a terrain evasion algorithm.
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