A method for detecting spatiotemporal conflicts of an aircraft planned route

Abstract

The application relates to a kind of aircraft plan route space-time conflict detection method, belong to flight safety assessment technical field.The application adopts space grid subdivision method to subdivide flight area into a series of discrete grid units, and simultaneously carries out time discrete subdivision, forms space-time integrated space-time coding system;The planned route is expressed as the grid unit set, and the grid coding set of buffer zone is calculated according to the early warning distance, whether there is impassable grid in the buffer zone is judged according to the quantitative expression of the scene environmental elements and the space-time coding of the object environmental elements, and whether the space-time grid coding of the safe flight buffer zone and the object environmental element grid coding are space-time intersected is judged, so as to realize the safety evaluation of the aircraft planned route.The method does not need complex space operation, and can be realized only by simple grid coding operation, greatly reduces the calculation amount, and improves the detection efficiency of the planned route space-time conflict.

Description

Technical Field

[0001] This invention relates to a method for detecting spatiotemporal conflicts in planned flight routes of aircraft, belonging to the field of flight safety assessment technology. Background Technology

[0002] To complete operational tasks, helicopters, drones, and other aircraft typically need to fly at low altitudes. However, the low-altitude flight environment is extremely complex. Factors such as undulating terrain, tall buildings, communication towers, bridges spanning rivers, and tall vegetation, as well as environmental factors like rain, snow, fog, thunderstorms, and other low-altitude aircraft, pose significant safety threats to low-altitude flight. Safety assessment based on planned flight routes uses spatiotemporal data of the operational environment as a basis. Before mission execution, it performs reasoning analysis on pre-planned flight routes to identify potential safety hazards, allowing for route modifications or alerting pilots to dangerous sections of the planned route, thereby improving the safety of low-altitude flight. Traditional spatial reasoning and analysis are based on spatial coordinates. With the increasing complexity of geometric structures, spatial computation algorithms are becoming increasingly complex, and the computational load is constantly increasing, placing enormous computational pressure on planned flight route safety assessment systems. Summary of the Invention

[0003] The purpose of this invention is to provide a spatiotemporal conflict detection method for planned flight routes of aircraft, so as to solve the problem of low conflict detection efficiency caused by the large amount of computation in the current safety assessment of planned flight routes of aircraft.

[0004] To solve the above-mentioned technical problems, this invention provides a method for detecting spatiotemporal conflicts in an aircraft's planned flight path. The method includes the following steps:

[0005] 1) The flight area is gridded to obtain the planned flight path data of the aircraft, and the spatial area range and time interval range are extracted from it and encoded respectively;

[0006] 2) Obtain field environment elements and object environment elements within the flight area, quantify the field environment elements, and perform spatiotemporal coding on the object environment elements;

[0007] 3) Determine the safe flight buffer zone for the planned route and add the grid cell codes within the buffer zone to the flight route code set;

[0008] 4) Determine whether there are static obstacles in the flight route code set based on the quantitative expression of field environmental elements within the flight area;

[0009] 5) Determine whether the flight route code set intersects with the dynamic environmental object elements in spatiotemporal terms based on the spatiotemporal codes of the object environmental elements within the flight area;

[0010] 6) Determine the safety level of the planned route based on the judgment results of steps 4) and 5) to achieve spatiotemporal conflict detection of the planned route.

[0011] This invention employs a spatial grid partitioning method to divide the flight area into a series of discrete grid cells, while simultaneously performing temporal discrete partitioning, forming a spatiotemporal integrated coding system. The planned flight path is represented as a set of grid cells, and the grid coding set of the buffer zone is calculated based on the warning distance. By quantifying the field environmental elements and spatiotemporally coding the object environmental elements, it determines whether there are impassable grid cells within the buffer zone and whether the spatiotemporal grid coding of the safe flight buffer zone intersects with the object environmental element grid coding, thereby achieving a safety assessment of the aircraft's planned flight path. This method does not require complex spatial calculations; it only requires simple grid coding operations, significantly reducing computational load and improving the efficiency of detecting spatiotemporal conflicts along the planned flight path.

[0012] Furthermore, in step 2), the quantification of the field environment elements involves calculating the collision avoidance attributes based on the environmental attributes within the grid cells. The calculation method for the collision avoidance attributes is as follows:

[0013]

[0014] A C The value indicates the collision avoidance attribute: 1 indicates an impassable grid, 0.5 indicates a passable grid but with a high risk, and 0 indicates a passable grid cell.

[0015] This invention determines the collision avoidance attributes of field environmental elements in the flight area and uses these attributes to quantify the field environmental elements, which can accurately express the impact of field environmental elements on flight safety and facilitate subsequent static obstacle identification.

[0016] Furthermore, the spatiotemporal encoding representation of the object environment elements in step 2) is as follows:

[0017] obj={ObjID,BondCode,lnnerCodeSet}

[0018] Wherein, ObjID represents the ID of the object element, BondCode represents the spatiotemporal grid code of the overall bounding box of the object element, and InnerCodeSet represents the set of spatiotemporal grid codes of the spatiotemporal features inside the object element.

[0019] This invention employs a two-layer coding mechanism to encode the environmental elements of the object, which can conveniently and quickly determine whether the set of flight route codes intersects with the dynamic environmental object elements in time and space, thus improving the efficiency of the determination.

[0020] Furthermore, the judgment process in step 5) is as follows:

[0021] Determine whether the overall spatiotemporal code of the object element and the flight path code set intersect. If they do not intersect, continue to detect other objects. If they intersect, determine whether the flight path code set intersects with the internal spatiotemporal code set of the object element. If they do not intersect, exit and continue to detect other objects. If they intersect, further determine whether the time overlaps. If the time does not overlap, exit and continue to detect other objects. If they overlap, determine whether it intersects with the spatiotemporal of the dynamic environment object element.

[0022] This invention first determines whether the overall spatiotemporal code of the object element and the flight path code set intersect. If they intersect, it then determines whether the flight path code set intersects with the internal spatiotemporal code set of the object element. Finally, it determines whether there is temporal overlap. This hierarchical determination method avoids some unnecessary judgment processes and further improves the judgment efficiency.

[0023] Furthermore, in step 3), the range of the safe flight buffer zone of the planned route is determined by the buffer distance, which is equal to the product of the aircraft's flight speed and the warning time.

[0024] The process of adding the grid cell code within the buffer range to the flight path code set is as follows:

[0025] The planned flight path of the aircraft is represented as a set of spatiotemporal grid codes. The spatial code part in the spatiotemporal code set of the planned flight path is searched for neighborhood according to a set hierarchy. When the distance between the neighboring grid cell and the flight path grid is less than the buffer distance, the neighboring grid code is added to the flight path code set.

[0026] This invention uses the aircraft's flight speed and warning time to determine the buffer zone distance, which can accurately determine the buffer zone range that affects aircraft flight safety, providing reliable data support for the subsequent accurate determination of the safety of planned routes.

[0027] Furthermore, the judgment process in step 4) is as follows:

[0028] Traverse all grids in the flight path code set, extract the collision avoidance attributes of each traversed grid, and classify grids with the collision avoidance attribute of "impassable" as grids containing static obstacles.

[0029] This invention utilizes the anti-collision properties of a grid to accurately determine whether there are static obstacles within the grid.

[0030] Furthermore, the safety level in step 6) is described using a safety factor, and the total threat factor for the planned route grid cells is:

[0031]

[0032]

[0033] Where ρ is the total threat factor of the planned flight path grid cells, n is the number of threat grid cells in the flight path coding set, and d k The minimum distance ρ between the k-th threat grid cell and the grid cells in the flight path. k Let d be the threat factor of the k-th threat grid cell to the safe low-altitude flight of the aircraft. o For buffer distance, threat grid cell refers to a grid in the flight path coding set that contains static obstacles or a grid in the flight path coding set that intersects with dynamic environmental object elements in space and time.

[0034] This invention uses the ratio of the minimum distance between a threat grid cell and a grid cell in the flight path to the buffer distance as a threat factor. The safety of a planned flight path is evaluated by the threat factor, which can reliably quantify the safety status of the planned flight path and accurately describe the safety status of the planned flight path.

[0035] Furthermore, the method also includes hierarchical display based on the magnitude of threat factors in the threat grid cells.

[0036] This invention quantifies and grades the safety level of planned routes by using threat factors, making the safety level of planned routes visible and helping to remind pilots to pay attention to dangerous sections of planned routes. Attached Figure Description

[0037] Figure 1 This is a flowchart of the spatiotemporal conflict detection method for the planned flight path of an aircraft according to the present invention. Detailed Implementation

[0038] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0039] Grid coding operations based on spatiotemporal grid partitioning can transform the judgment of spatial relationships of complex geometric objects into the judgment of spatial relationships of grid cells with regular geometric structures. Grid coding operations utilize mathematics and computer science to study the content and characteristics of grid coding algebraic space, including basic operations such as mutual conversion between grid codes and geographic coordinates, hierarchical search, and neighborhood search. It also includes spatial relationship operations for judging the topology, measurement, and orientation relationships of grid cells, which can be used to judge the spatiotemporal relationships of spatial elements. Therefore, this invention provides a spatiotemporal conflict detection method for aircraft planned routes using grid coding. This invention employs a spatial grid partitioning method to divide space into a series of discrete grid cells and extends to the time dimension to achieve discrete partitioning of time, forming a spatiotemporal integrated spatiotemporal coding system. Based on grid coding, it realizes the grid-based organization and management of spatiotemporal elements and planned route data in the low-altitude environment. The safety assessment of the aircraft's planned route is achieved by judging the spatial relationships between grid cells and their sets. The implementation process of this method is as follows: Figure 1 As shown below, a detailed explanation will be provided with specific examples.

[0040] 1. Obtain the planned flight path data of the aircraft, extract the spatial area range and time interval range from it, and encode them respectively.

[0041] The planned flight path of the aircraft includes a series of waypoints, each of which includes the following parameters: the longitude x of the aircraft. i The latitude of the aircraft is y i The flight altitude of the aircraft z i (Unit: meters) The flight speed v of the aircraft i The arrival time t of the spacecraft i These parameters are provided in text format. In this embodiment, the specific details of the planned flight route are as follows:

[0042]

[0043]

[0044] The flight environment information for the corresponding area is stored in a database and can be obtained by calling an interface. The safety of the planned route can be assessed based on the planned route information and the flight environment information.

[0045] Based on the acquired planned flight path data, the spatial region range FlyBond(MinL, MinB, MaxL, MaxB) is extracted. The spatial region is then divided according to the given spatial resolution SpaceLevel (SpaceLevel = 1.0 meter in this embodiment), and encoded according to level, row, column, and height to obtain the spatial code SpaceCode of the grid cell.

[0046] SpaceCode=(level,row,col,height}

[0047] The values ​​for level, row, col, and height are all integers.

[0048] Based on the acquired planned flight path data, the time range TimeRange is extracted, and the time is divided according to the given time resolution TimeLevel. In this embodiment, the time range TimeRange for the aircraft to pass through the flight path is 48 minutes and 32 seconds. The time is divided according to the given time resolution TimeLevel = 1 second. The time code time is used for encoding. The number of time codes TimeRange / TimeLevel = 2912, then: time∈[0,2912].

[0049] 2. Acquire field environment elements and object environment elements within the flight area, quantify the field environment elements, and perform spatiotemporal coding on the object environment elements.

[0050] Field environmental elements refer to a class of environmental elements that are continuously distributed in space and time, such as surface elevation, soil type, atmospheric temperature, and visibility. This type of data represents the spatiotemporal distribution characteristics of a certain attribute in the flight environment, making it very suitable for quantitative expression based on spatial grid cells. In this implementation, environmental information such as terrain and meteorology is extracted from the environmental database, and collision avoidance attributes are calculated based on the environmental attributes within the grid cells. The specific calculation method is as follows:

[0051]

[0052] A C The grid indicates the collision avoidance attribute: 1 represents the terrain filling grid, indicating that the road is impassable; 0.5 represents the severe weather conditions filling grid, indicating that the road is passable but with a high risk; and 0 represents the good weather conditions filling grid, indicating that the road is passable.

[0053] Environmental elements refer to features such as tall buildings, high-voltage power lines, communication towers, and tall vegetation within the flight area. Data on tall buildings, high-voltage power lines, communication towers, and tall vegetation are extracted from the environmental database, and these environmental elements are represented using temporal and spatial grid encoding.

[0054] Obj={ObjID, BondCode, InnerCodeSet}

[0055] Here, ObjID represents the ID of the object feature, BondCode represents the spatiotemporal grid code of the overall bounding box of the object feature, and InnerCodeSet represents the set of spatiotemporal grid codes of the spatiotemporal features inside the object feature. Since these are static features, the time codes in them are invalid values.

[0056] 3. Determine the spatiotemporal grid coding set of the safe flight buffer zone for the planned route.

[0057] The time and space information of the planned route is encoded using STcode. i This means that the planned flight path of the aircraft is represented as a set of spatiotemporal grid codes:

[0058] LineSet={Stcode1,Stcode2,…,STcode i ,…,Stcode n}

[0059] Where n is the number of grid cells the planned route passes through, and STcode is the spatiotemporal code;

[0060] Perform a neighborhood search at a specified level on the spatial coding portion of the planned flight path's spatiotemporal coding set, LineSet, and add the grid cell codes within the buffer range to the flight path coding set, FlyRoadCodeSet. The buffer range is determined jointly based on the aircraft's flight speed and warning time, let d o t is the buffer distance. o For the warning duration, v o Let be the flight speed of the aircraft, then:

[0061] d o =v o ×t o

[0062] Let the distance between the neighboring grid cell and the flight path grid be d. i The calculation formula is as follows:

[0063]

[0064] When d i <d o If so, the neighborhood grid code will be added to the FlyRoadCodeSet collection.

[0065] In this embodiment, the warning duration t0 = 60 seconds, and the aircraft's flight speed v o = 50 m / s, then the warning distance d o =3000 meters. All grid codes within 3000 meters of the flight path grid are placed into the FlyRoadCodeSet.

[0066] 4. Determine whether there are static obstacles within the safe flight buffer zone of the planned flight path.

[0067] Iterate through all grid codes in FlyRoadCodeSet and determine if there are grid cells with land, water, mixed land / air, or mixed water / air fill attributes. If so, indicate a land collision threat. The determination method is to extract the FRcode from the FlyRoadCodeSet. i Extract its anti-collision attribute A c , when A c =1 indicates a threat of ground collision, requiring early warning.

[0068] 5. Determine whether the safe flight buffer zone of the planned route intersects with the dynamic environmental object elements in time and space.

[0069] Determining whether the safe flight buffer zone of the planned flight path intersects with the dynamic environment object elements in spatiotemporal terms mainly involves checking whether the overall spatiotemporal code BondCode of the object element and the flight path code set FlyRoadCodeSet intersect. If they do not intersect, the system continues to detect other objects. If they intersect, the system further checks whether the flight path code FlyRoadCodeSet intersects with the internal spatiotemporal code set InnerCodeSet of the object element. If they do not intersect, the system exits and continues to detect other objects. If they intersect, the system further checks whether the time overlaps. If the time does not overlap, the system exits and continues to detect other objects. If they overlap, the system indicates a flight obstacle threat.

[0070] The specific method involves calling the `CalTopoRelation(CodeSet1, CodeSet2)` function to determine whether the overall spatiotemporal code of the object element and the flight path code set intersect. The `CalTopoRelation(CodeSet1, CodeSet2)` function determines the spatial relationship by judging the size of the grid codes. For example, within the same coding level, if row1 = row2, col1 = col2, and height1 = height2, then the spaces intersect. If they do not intersect, the detection of other objects continues. If they intersect, the detection of the flight path code and the internal spatiotemporal code of the object element is further checked. If they do not intersect, the detection of other objects is stopped. If they intersect, the detection of time overlaps is further checked. If the time overlaps, the detection of other objects is stopped; if they overlap, a flight obstacle threat is indicated.

[0071] 6. Determine the safety level of the planned route.

[0072] To visually represent the flight safety threats faced by an aircraft along its planned flight path, we search for threat grid cells within the buffer zone of the planned flight path's grid cells. Let d be the minimum distance between the threat grid cell and the grid cell in the flight path. k , ρ k Let d be the threat factor of this threat grid cell to the safe low-altitude flight of the aircraft. k With d o The ratio, d o The buffer distance is:

[0073]

[0074] Let ρ be the total threat factor of the planned route grid cells, then:

[0075]

[0076] Where n is the number of threat grid cells in the buffer.

[0077] To more vividly describe the safety level of planned flight routes, this invention uses layered coloring based on the threat factors of the planned flight route grid units and draws them in a three-dimensional scene, resulting in a visualization effect of the safety level of helicopter planned flight routes. This allows pilots to intuitively and clearly understand the safety level of planned flight routes.

[0078] This invention employs a spatial grid partitioning method to divide space into a series of discrete grid units and extends this into the time dimension, achieving discrete partitioning of time and forming a spatiotemporal coding system. Based on this grid coding, it enables the grid-based organization and management of spatiotemporal elements and planned flight path data in low-altitude environments. By judging the spatial relationships between grid units and their sets, it achieves safety assessment of the planned flight path for aircraft. This solves the problem of safety assessment of planned flight paths in low-altitude dynamic and complex flight environments, improves the detection efficiency of spatiotemporal conflicts in planned flight paths, and can alert pilots to dangerous sections of planned routes. It can be applied to the planning of operational missions for helicopters, drones, and other aircraft.

Claims

1. A method for detecting spatiotemporal conflicts of flight plans of aircraft, characterized in that, The detection method comprises the following steps: 1) performing grid processing on a flight area, obtaining aircraft planned route data, extracting a spatial area range and a time interval range therefrom, and respectively encoding them; 2) obtaining field environment elements and object environment elements in the flight area, quantitatively expressing the field environment elements, and calculating their anti-collision properties, and expressing the object environment elements in a time-space code; an ID representing an object environment element, a whole spatiotemporal grid code representing the object environment element, a set of internal spatiotemporal grid codes representing the object environment element; 3) determining a safe flight buffer zone of the planned route, and encoding grid units in the buffer zone range into a flight route code set; 4) determining threat grid units according to the anti-collision properties of the field environment elements of each grid unit in the flight route code set, wherein the threat grid units refer to grid units affected by the anti-collision properties to normal passage; 5) taking a time-space intersecting grid unit as a threat grid unit, wherein the time-space intersecting grid unit determination process comprises: first judging whether the overall time-space code of the dynamic object environment element intersects with the flight route code set, if intersecting, judging whether the internal time-space code of the dynamic object environment element intersects with the flight route code set, and if intersecting and time overlapping, considering that it is a time-space intersecting grid unit; 6) calculating the minimum distance between each threat grid unit and the grid units in the route, taking the ratio of the minimum distance to a buffer distance as a threat factor of each threat grid unit, and statistically obtaining the safety degree of the planned route by the threat factors of the threat grid units, so as to realize time-space conflict detection of the planned route, wherein the buffer distance is determined according to the flight speed and the warning time.

2. The method of detecting space-time conflicts of flight plans of aircraft according to claim 1, wherein, The calculation method of the anti-collision properties in step 2) is as follows: A C represents the collision avoidance property, 1 represents an impassable grid, 0.5 represents a passable but high risk, and 0 represents a passable grid cell.

3. The method of detecting a spatiotemporal conflict of flight plans according to claim 1 or 2, wherein, The range of the safe flight buffer zone of the planned route in step 3) is determined by the buffer distance, and the buffer distance is equal to the product of the flight speed of the aircraft and the warning time.

4. The method of detecting space-time conflicts of flight plans of aircraft according to claim 3, wherein, The process of encoding the grid units in the buffer zone range into the flight route code set is as follows: The aircraft planned route is expressed as a set of time-space grid code sets; the spatial code part of the time-space code set of the planned route is subjected to neighborhood search according to a set level, and when the distance between the neighborhood grid unit and the route grid is less than the buffer distance, the neighborhood grid code is added to the flight route code set.

5. The method of detecting space-time conflict of flight aircraft flight plan route according to claim 2, wherein, The judgment process of step 4) is as follows: All grids in the flight route code set are traversed, the anti-collision properties of each traversed grid are extracted, and the grid with an anti-collision property of being impassable is taken as a grid with a static obstacle.

6. The method of detecting space-time conflict of flight aircraft flight plan route according to claim 1, wherein, The calculation formula of the threat factor in step 6) is as follows: wherein is the total threat factor of the planned route grid cells, n is the number of threat grid cells in the flight route encoding set, the k minimum distance of the th k threat grid cell to the grid cells in the flight route, is the buffer distance.

7. The method of detecting space-time conflicts of flight plans of aircraft according to claim 6, wherein, The method further comprises hierarchical display according to the size of the threat factor in the threat grid unit.

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