A method for target operation safety airspace planning based on space-time grid

Abstract

The application provides a target operation safety airspace planning method based on a space-time grid, comprising the following steps: step 1, dividing the whole space and time; step 2, setting up an airspace to be analyzed and calculated from a geographic space, and dividing the airspace according to a space division level; step 3, analyzing a fixed unusable airspace in the airspace, and dividing the airspace according to the space division level; step 4, analyzing a dynamically changing unusable airspace in the airspace, and dividing the airspace according to the space division level; step 5, calculating a time of the target to reach each space division grid; step 6, associating a time vector with each element in the set again; step 7, expanding the elements in the time vector associated with the grid element; step 8, calculating an available airspace grid set; step 9, calculating a safety interval grid; and step 10, calculating an actual available airspace of a dynamic target within a preset range. The application improves the safety of the airspace under the premise of ensuring the accuracy.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of airspace planning, and particularly relates to a target operation safety airspace planning method based on a space-time grid. BACKGROUND

[0002] The GeoSOT technology of global longitude and latitude subdivision grid proposed by Peking University is an equi-longitude and latitude subdivision grid. Through extension of the earth, the space on the earth surface can be subdivided into grids according to degrees and minutes, so as to divide the space on the earth surface into continuous multiple levels and non-overlapping grids. Based on the subdivision grid, complex three-dimensional space operations can be converted into simple coding comparison, XOR, union, etc., greatly improving the operation efficiency. At present, the technology has been widely applied in meteorology, surveying and mapping, military and other fields, and the effect is remarkable. In the aspect of airspace planning, the grid subdivision technology can be used to solve path airspace allocation, route planning, conflict detection, etc., and can be combined with time subdivision coding and frequency subdivision coding for comprehensive and integrated analysis of airspace characteristics.

[0003] However, the existing airspace planning or airspace space-time conflict detection method generally describes the space (including safety interval) occupied by the target according to the "bounding box" mode and selects the coding level, and the precision is not high, and in the association of space coding and time coding, the continuity of the time grid coding in the space grid coding is ignored. SUMMARY

[0004] The technical problem to be solved by the application is to provide a target operation safety airspace planning method based on a space-time grid, which comprises the following steps:

[0005] Step 1, setting a space subdivision level L s and a time subdivision level L t according to the size and motion characteristics of the target, and subdividing the entire space and time;

[0006] Step 2, based on the motion range of the target, setting an airspace A to be analyzed and calculated from the geographical space, and subdividing the airspace A into a three-dimensional space grid set S according to the space subdivision level L s ;

[0007] Step 3, analyzing the fixed unusable airspace in the airspace A, and subdividing the airspace into a three-dimensional space grid set M0 according to the space subdivision level L s ;

[0008] Step 4, analyzing n dynamic change unusable airspaces in the airspace A, and subdividing the airspaces into three-dimensional space grid sets M1, M2, …, M s corresponding to the n airspaces according to the space subdivision level L n ;n represents the third dimension space grid set corresponding to the nth space domain;

[0009] Step 5, based on the time subdivision level L t , the time when the target reaches each space subdivision grid in the third dimension space grid set S is calculated, and a time vector V t0 is associated with the space grid n The time subdivision grid set T0, T1, T2, …, T n associated with the space grid set is calculated t1 ;

[0010] Step 6, traverse the third dimension space grid set S, and associate each element in the set with a time vector V n , which is composed of elements in T0 and T1, T2, …, T t1 , and the elements in each time vector are arranged in ascending order from small to large;

[0011] Step 7, using the time expansion method, the elements in the time vector V t2 associated with the grid elements are expanded to form a new time vector V s ;

[0012] Step 8, according to the principle that the space grids do not overlap or the space grids overlap but the time grids do not overlap, the available space grid set S1 and the unavailable space grid set S'1 are calculated;

[0013] Step 9, for the space grid set S1, using the space erosion method, the safety interval space grid is calculated to obtain the actual available space three-dimensional grid set S2;

[0014] Step 10, for the actual available space grid set S2, the space A1 corresponding to the grid set is calculated, which is the actual available space domain of the dynamic target within the preset range.

[0015] Step 2 includes: selecting the starting coordinate point P s (J s , W s , H e ) and the ending coordinate point P e (J e , W e , H s ) of the target activity in the geographic coordinate system, forming a cuboid space A, according to the longitude interval ΔJ, latitude interval ΔW, and height interval ΔH corresponding to L s (J s , W s , H s ) to the ending point P e (Je , W e , H e ), according to the starting longitude J s to the ending longitude J e , the starting latitude W s to the ending latitude W e , the starting height H s to the ending height H e , the three dimensions are traversed, and the grid code corresponding to each discrete point is calculated to form a three-dimensional space grid set S.

[0016] In step 5, the time for the target to reach each space subdivision grid in the three-dimensional space grid set S is calculated using the following formula:

[0017]

[0018] Wherein, f(t) represents the time for the target to reach the subdivision grid, l represents the distance from the grid to the initial point of the target, v represents the speed of the target; t0 is the start time of the whole planning; t1 is the start time, and Δt is the duration.

[0019] In step 5, according to formula (1), the time for the target to reach each space subdivision grid in the three-dimensional space grid set S is calculated and stored in the time vector V t0 .

[0020] In step 6, the time vector V t1 is constructed using the following method: traversing the three-dimensional space grid set S, for each space subdivision grid s i in the three-dimensional space grid set S, it is queried whether it exists in the three-dimensional space grid set M i , 0≤i≤n, if it exists, the time subdivision t i in the corresponding time subdivision grid set T i is taken out and stored in V t1 in ascending order.

[0021] In step 7, the element set in the time vector V t1 is:

[0022] V t1 = [t0, t1, …, t i , …, t n ] (2)

[0023] The acquisition method of t i in formula (2) is: traversing the three-dimensional space grid set S, for each space subdivision grid s i in S, it is queried whether it exists in M i , if it exists, the corresponding T iTime division t in i Take out and store in V in ascending order t1 middle;

[0024] Let the time segmentation level L t The corresponding time scale is R t , set the time dilation threshold TH t for:

[0025] TH t =K t ×R t (3)

[0026] where K t is an integer;

[0027] Time vector V t1 The element t in i The specific expansion method is shown in formula (4):

[0028]

[0029] Where F(t i ) is the element t i The method to obtain the elements of the expanded vector set is as follows: First, use t i Based on R t For the interval, at t i Insert K before t elements until the inserted element is less than or equal to the previous element t i-1 , then, t i Based on R t For the interval, at t i Then insert K t elements until the inserted element is greater than or equal to the next element t i+1 , and V t1 After each element in is operated according to formula (4), a new time vector V is formed. t2 .

[0030] Step 8 includes: traversing the three-dimensional space grid set S, for each spatial subdivision grid s in the three-dimensional space grid set S i , remove s i The corresponding V t0 and V t2 , V t0 Indicates that the target reaches the grid s i Time, V t2 Represents the unavailable time set; then traverse V t0 Each element t in i , judge t iwhether or not V t2 If not, s i is stored in S1, otherwise, s 1i is stored in the unavailable spatial grid set S'1, thus obtaining the available spatial grid set S1 and the unavailable spatial grid set S'1.

[0031] Step 9 includes: knowing the relationship of S, S1 and S'1 as shown in (5):

[0032]

[0033] wherein S1 represents the available spatial grid code set, s 1i is an element in the S1 set; S'1 represents the unavailable spatial grid code set, s' 1i is an element in the S'1 set.

[0034] In step 9, let the spatial subdivision level L s corresponding to the spatial scale be R s , and set the spatial corrosion threshold TH s as follows:

[0035] TH s = K s × R s (6)

[0036] wherein K s is an integer;

[0037] The specific inflation method of the element s' 1i in the three-dimensional spatial grid S'1 is shown in formula (7):

[0038]

[0039] wherein S'2(i) represents the grid set after s' 1i is expanded in the longitude direction, the latitude direction and the height direction, I represents the expansion interval in the longitude direction, J represents the expansion interval in the latitude direction, and K represents the expansion interval in the height direction.

[0040] In step 9, first, expand a cube with a side length of (2×K s +1)× R s in the three-dimensional space with s' 1i as the center, and increase (2×K s +1) 3 subdivision grids; then, (2×K s +1) 3 subdivision grids are removed.The grid is stored in a new grid set S'2, forming a new unusable airspace grid set S'2, and finally the grid of S'2 is removed from the three-dimensional space grid set S, that is, the actual available space three-dimensional grid set S2 is formed.

[0041] Advantages: the application has the following advantages: 1. The application encodes the fixed unusable airspace and the dynamic unusable airspace in space, and describes the two types of airspace by using time coding set (i.e. time profiling coding in a time range); 2. The application expands the time coding associated with a certain space coding, reserves a safety interval while preserving the continuity of time; 3. The application establishes a safety interval between the available space coding and the unusable space coding by corroding the space grid profiling coding, thereby improving the safety of the airspace under the premise of ensuring the accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0042] The above and / or other aspects of the application will become more apparent by describing in detail the preferred embodiments thereof with reference to the attached drawings.

[0043] Figure 1 The technical solution of the application is shown in the flow chart.

[0044] Figure 2 The space profiling level table is shown in the table.

[0045] Figure 3 The time profiling level table is shown in the table.

[0046] Figure 4 The space grid example of the airspace profiling is shown in the figure.

[0047] Figure 5 The example airspace in the implementation method is shown in the figure. DETAILED DESCRIPTION

[0048] The application provides a target running safety airspace planning method based on space-time grid, comprising:

[0049] Step 1, according to the target size and motion characteristics, etc., setting the space profiling level L s and the time profiling level L t , and profiling the whole space and time.

[0050] According to the GeoSOT global longitude and latitude grid profiling technology, the three-dimensional space grid profiling level is shown in the figure Figure 2 , L s is selected from 0 to 32, after selecting a level, the whole three-dimensional space is divided into several space grid units according to the scale corresponding to the level, forming a space grid coding set; similarly, the time grid profiling level is shown in the figure Figure 3 , Lt The value range of L is 0 to 63. After selecting a level, the entire time is divided into several time grid units according to the scale corresponding to the level, forming a complete set of time grid codes.

[0051] Step 2, based on the target motion range, a space A to be analyzed and calculated is set in the geospatial, and the space A is divided according to the spatial division level L s to form a three-dimensional spatial grid set S.

[0052] Selecting a starting coordinate point P s (J s , W s , H s ) and an ending coordinate point P e (J e , W e , H e ) of the target activity in the geographic coordinate system, forming a cuboid space A, and according to the longitude interval ΔJ, latitude interval ΔW, and height interval ΔH corresponding to L s , traversing from the starting point P s (J s , W s , H s ) to the ending point P e (J e , W e , H e ) according to the three dimensions of longitude J s to J e , latitude W s to W e , and height H s to H e , as shown in Figure 4 , calculating the grid code corresponding to each discrete point to form a three-dimensional spatial grid set S.

[0053] Step 3, analyzing the fixed unusable space in the space A (such as mountains, high-rise buildings, no-fly zones, etc.), and dividing the space according to the spatial division level L s to form a three-dimensional spatial grid set M0.

[0054] Such space is generally irregular, and if it is a regular cuboid space, the method in step 2 can be used to convert it into a grid set. For irregularly shaped space, first "cut" the space into multiple continuous sub-spaces according to the scale value corresponding to L s in the height direction, then calculate the grid set of each sub-space to form a three-dimensional spatial grid set M0 of the fixed unusable space in the space A.

[0055] Step 4, analyze n dynamic changing unusable airspace in airspace A (such as the flight path of other moving targets, temporary control airspace, etc.), and classify the airspace according to the spatial division level L s , and divide to form a three-dimensional spatial grid set M1, M2, …, M n .

[0056] Referring to the calculation method in step 3, the temporary control airspace can be converted into a set of three-dimensional spatial grids, which will not be described here. The flight path of a moving target is composed of a series of consecutive waypoints. In the geographic coordinate system, each point already contains longitude, latitude, and altitude information. The grid code corresponding to the waypoint is calculated, and the corresponding three-dimensional spatial grid set is formed.

[0057] Step 5, based on the time division level L t , calculate the time when the target reaches each spatial division grid in S, and associate a time vector V t0 with the spatial grid. n , calculate the time division grid set T0, T1, T2, …, T n associated with the spatial grid set M0, M1, M2, …, M t1 .

[0058] For the available airspace planning of a certain moving target, the time calculation method associated with each spatial division grid in the three-dimensional spatial grid set is as follows:

[0059]

[0060] In formula (1), formula one represents the time calculation method of the moving target in a certain spatial grid, l represents the distance from the grid to the initial point of the target, and v represents the speed of the target; formula two represents the time calculation method of the fixed unusable airspace, t0 is the start time of the entire planning; formula three represents the time calculation method of the dynamic unusable airspace, t1 is the start time, and Δt is the duration time.

[0061] Step 6, traverse the three-dimensional spatial grid set S, and associate a time vector V t1 with each element in the set, which is composed of elements in T0 and T1, T2, …, T n , and the elements in each time vector are arranged in ascending order from small to large.

[0062] V t1 The construction method of the time vector is as follows: traverse the three-dimensional spatial grid set S, and for each spatial division grid s i in S, query whether it exists in M i , if it exists, take out the time division t i in T i corresponding to it, and store it in V t1In.

[0063] Step 7, the elements in the time vector V t1 are expanded to form a new time vector V t2 .

[0064] Let the element set in the time vector V t1 be:

[0065] V t1 = [t0, t1, …, t i , …, t n ] (2)

[0066] Let the time scale corresponding to the subdivision level L t be R t , and set the time "expansion" threshold TH t as:

[0067] TH t = K t × R t (3)

[0068] K t in formula (3) is an integer, and the larger K t is, the greater the time "expansion" is, that is, the greater the safety interval range between the safe airspace and the unusable airspace.

[0069] The specific "expansion" method of the element t t1 in the time vector V i is shown in formula (4):

[0070]

[0071] First, based on t i , R t is the interval, K t elements are inserted before t i until the inserted element is less than or equal to the previous element t i-1 . Then, based on t i , R t is the interval, K t elements are inserted after t i until the inserted element is greater than or equal to the next element t i+1 . After each element in V t1 is operated according to formula (4), a new time vector V t2 is formed.

[0072] Step 8: Calculate the available spatial grid set S1 and the unavailable spatial grid set S′1 according to the principle that the spatial grids do not overlap, or the spatial grids overlap but the time grids do not overlap.

[0073] The calculation method of the available spatial grid set S1 is as follows: First, traverse the three-dimensional spatial grid set S, and for each spatial subdivision grid s in S i , remove s i The corresponding V t0 and V t2 ; Then traverse V t0 Each element t in i , judge t i Is there a V t2 If it does not exist, then s i Store it in S1, otherwise store it in S′1, so as to obtain the available spatial domain grid set S1 and the unavailable spatial domain grid set S′1.

[0074] Step 9: For the spatial grid set S1, a spatial "erosion" method is used to calculate the safe interval spatial grid to obtain the actual available spatial three-dimensional grid set S2.

[0075] The calculation method of the actual available spatial grid set S2 is given by the relationship between S, S1 and S′1 as shown in (5):

[0076]

[0077] Let the spatial subdivision level L s The corresponding spatial scale is R s , set the spatial "erosion" threshold TH s for:

[0078] TH s =K s ×R s (6)

[0079] K in formula (6) s is an integer, K s The larger it is, the greater the space "erosion", that is, the larger the safety interval between the actually used safe airspace and the unusable airspace.

[0080] Since S1 and S′1 are complementary, the “expansion” of S′1 is the “erosion” of S1. The element s′ in the three-dimensional space grid S′1 1i The specific "expansion" method is shown in formula (7):

[0081]

[0082] First, in three-dimensional space, s′ 1iFor the center, the expansion forms a side length of (2 x K s +1) x R s cube, increase (2 x K s +1) 3 split grid; then, (2 x K s +1) 3 grid storage in the new grid set S'2, form a new unusable airspace grid set S'2; finally, from the three-dimensional space grid set S, eliminate the grid of S'2, that is, form the actual available space three-dimensional grid set S2.

[0083] Step 10, for the space grid set S2, calculate the space A1 corresponding to the grid set, that is, the actual available airspace of the dynamic target within the preset range.

[0084] Embodiment

[0085] As Figure 1 shown, it is the flow chart of the technical scheme of the application. In this embodiment, based on the existing target and the preset activity airspace, fixed unusable airspace, dynamically changing unusable airspace, etc., as the original data source, and combined with the processes of time division and "inflation", space division and "erosion", the technical scheme of the application is described in detail.

[0086] Step 1, according to the size and motion characteristics of the target, set the space division level L s and the time division level L t , and divide the entire space and time.

[0087] GeoSOT global latitude and longitude grid division technology is currently a common method, and the specific original scheme will not be described again. In this embodiment, taking planning the safety flight airspace of a helicopter as an example, the space division level is selected as L s 23, that is, the scale is 8 meters, and the time division level is L t 52, that is, the scale is 2 seconds.

[0088] Step 2, based on the target motion range, set up the airspace A that needs to be analyzed and calculated from the geographic space, and divide the airspace A according to the space division level L s to form a three-dimensional space grid set S.

[0089] In this embodiment, the situation of the preset activity airspace A of the helicopter is as shown in Figure 5 The starting point coordinates of the A airspace are P s (120.0, 34.0, 0), and the end point coordinates are P e (120.25, 34.125, 1000).

[0090] According to the space division level Ls = 23, solve the three-dimensional space grid set S, a total of 3600*1800*125 grid codes, the middle element of the set S is: [3c000000110000000000000017, 3c000800110000000000000017, 3c001000110000000000000017, 3c001800110000000000000017, 3c002000110000000000000017, …, 3c1e0000110ee800000003e817].

[0091] Step 3, analyze the fixed unusable airspace in the airspace A (such as mountains, high-rise buildings, restricted flight areas, etc.), and classify the airspace according to the space division level L s , and the three-dimensional space grid set M0 is divided.

[0092] In this embodiment, there are two fixed unusable restricted flight areas in the airspace A, which are A1: a cuboid airspace composed of (120.03409, 34.10455, 0) to (120.05114, 34.08182, 1000); A2: a cuboid airspace composed of (120.15341, 34.04886, 0) to (120.18182, 34.03182, 1000).

[0093] According to the space division level L s = 23, solve the three-dimensional space grid set M0, form 246*328*125+410*246*125 grid codes, and the elements in the set M0 are: [3c041000110c80000000000017, 3c041800110c80000000000017, 3c042000110c80000000000017, 3c042800110c80000000000017, …, 3c0620001109b000000003e817, …, 3c1260001105b8000000000017, 3c1268001105b8000000000017, 3c1270001105b8000000000017, 3c1278001105b8000000000017, …, 3c15b0001103b000000003e817].

[0094] Step 4, analyze the n dynamic changeable unusable airspace in the airspace A (such as the flight path of other moving targets, temporary control airspace, etc.), and classify the airspace according to the space division level L s, and the three-dimensional space grid sets M1, M2, …, M n .

[0095] In this embodiment, there is a temporary control airspace A3 in the airspace A: the cuboid airspace composed of (120.08864, 34.06591, 0) to (120.1125, 34.08864, 1000). According to the level L s = 23 of the space division in step 1, the A3 space grid set M1 is solved, forming 458*328*125 grid codes, and the elements in the three-dimensional space grid M1 set are: [3c0a98001107c8000000000017, 3c0aa0001107c8000000000017, 3c0aa8001107c8000000000017, 3c0ab0001107c8000000000017, …, 3c0d6000110a9800000003e817].

[0096] In this embodiment, there is a temporary control airspace A4 (120.011364, 34.07727, 0) to (120.14318, 34.10227, 1000) in the airspace A. According to the level L s = 23 of the space division in step 1, the A4 space grid set M2 is solved, forming 490*328*125 grid codes, and the elements in the three-dimensional space grid M2 set are: [3c014000110930000000000017, 3c014800110930000000000017, 3c015000110930000000000017, 3c015800110930000000000017, …, 3c111800110c4000000003e817].

[0097] In this embodiment, there is a moving target's flight route in the air A, and the coordinate point set is L1: [(120.05455, 34.12500, 300), (120.06364, 34.11136, 300), (120.08182, 34.10000, 300), (120.10227, 34.09545, 300), (120.12045, 34.08636, 300), (120.15909, 34.075, 300), (120.18864, 34.05909, 300), (120.22273, 34.05227, 300), (120.23409, 34.04091, 300), (120.24545, 34.00682, 300), (120.25, 34.00455, 300)]. According to the space division level L s = 23 in step 1, the L1 space grid set M3 is solved, 3008 grid codes are formed, and the elements in the three-dimensional space grid M3 set are: [3c068000110ee8000000012c17, 3c078800110d40000000012c17, 3c09b000110c00000000012c17, …, 3c1e0000110080000000012c17].

[0098] In this embodiment, there is a moving target's flight route in the air A, and the coordinate point set is L2: [(120.22727, 34.0, 800), (120.21591, 34.01136, 800), (120.21136, 34.03182, 800), (120.2, 34.04318, 800), (120.19318, 34.07273, 800), (120.17955, 34.08409, 800), (120.17273, 34.10455, 800), (120.15, 34.11136, 800), (120.13636, 34.125, 800)]. According to the space division level L s = 23 in step 1, the L2 space grid set M4 is solved, 2158 grid codes are formed, and the elements in the three-dimensional space grid M4 set are: [3c1b3000110000000000032017, …, 3c19c800110140000000032017, 3c1940001103b0000000032017, …, 3c105000110ee8000000032017].

[0099] Step 5, based on the time division level L t, calculate the time of the target reaching each spatially partitioned grid in S, and associate a time vector V with the spatial grid t0 , calculate M0, M1, M2, …, M n , calculate the time partitioned grid set T0, T1, T2, …, T n associated with the spatial grid set.

[0100] In this embodiment, the planning start time t0 is set to August 8, 2022, 8:08:08 (t0 can be arbitrarily set, and other times are changed based on t0), the time partitioning level uses L t = 38 in step 1. The speed of the helicopter is set to 80 meters per second. According to formula (1) formula one, the helicopter needs 0.2 seconds to reach the first grid, 0.4 seconds to reach the second grid, and so on, and V t0 is obtained in turn: [4754003402457874432, 4754003402459971584, 4754003402462068736, …, 4754003403949243392].

[0101] In this embodiment, the calculation method of the time partitioned grid set T0 associated with the fixed unusable airspace M0 is referred to formula (1) formula two, according to L t = 41 in step 1, T0 = [4754003402457874432, 4754003402459971584, 4754003402462068736, …, 4754003411047809024, …].

[0102] In this embodiment, the effective time of the temporary control airspace A3 is set to t0+10min to t0+20min, and the elements in the time partitioned grid set T1 associated with the three-dimensional space set M1 corresponding to A3 are: [4754003403128963072, 4754003403131060224, 4754003403133157376, …, 4754003403800051712].

[0103] In this embodiment, the effective time of the temporary control airspace A4 is set to t0+5min to t0+15min, and the elements in the time partitioned grid set T2 associated with the three-dimensional space set M2 corresponding to A4 are: [4754003402793418752, 4754003402795515904, 4754003402797613056, …, 4754003403456118784].

[0104] In this embodiment, the target above L1 route starts from t0+3 minutes, enters from the first point and flies along L1 at the speed of 60m / s, and the time set T3 associated with the M3 grid set corresponding to L1 is: [4754003402659201024, 4754003402659337216, 4754003402659473408, …, 4754003403095408640].

[0105] In this embodiment, the target above L2 route starts from t0+9 minutes, enters from the first point and flies along L2 at the speed of 90m / s, and the time set T4 associated with the M4 grid set corresponding to L2 is: [4754003403061854208, 4754003403061944320, 4754003403062035456, …, 4754003403275763712].

[0106] Step 6, traverse the three-dimensional space grid set S, and associate a time vector V with each element in the set t1 , and each element in T0 and T1, T2, …, T n is arranged in ascending order.

[0107] In this embodiment, take the K point (120.113, 34.075, 300) in the attached Figure 5 as an example, the space grid code corresponding to the K point is: 3c0d70001108f0000000012c17, the K point is in A3, A4 and L1, the subdivision time associated with the K point in T1 is: [4754003403128963072, 4754003403131060224, 4754003403133157376, …, 4754003403800051712], the subdivision time associated with the K point in T2 is: [4754003402793418752, 4754003402795515904, 4754003402797613056, …, 4754003403456118784], and the time associated with the K point in T3 is: 4754003402801807360. Then the V t1 of the K point is:

[0108] [4754003402793418752, 4754003402795515904, 4754003402797613056, …, 4754003402801807360, …, 4754003403128963072, 4754003403131060224, 4754003403133157376, …, 4754003403800051712, …, 4754003403456118784].

[0109] Step 7: Use the time “dilation” method to dilate the time vector V associated with the grid elements. t1 The elements in are expanded to form a new time vector V t2 .

[0110] In this embodiment, L t =41 corresponds to the time scale R t For 2 seconds, set K t =4, then according to formula (2), the time "expansion" threshold TH t = 8 seconds. The time V associated with point K t1 Taking the time code 4754003402801807360 in the example, it can be seen from formula (4) that the V associated with the K point after expansion is t2 is: [4754003402793418752, 4754003402795515904, 4754003402797613056, ..., 4754003402799710208, 4754003402801807360, 4754003402803904512, 4 754003402806001664……,4754003403128963072,4754003403131060224,4754003403133157376,……,4754003403800051712,……,4754003403456118784].

[0111] Step 8: Calculate the available spatial grid set S1 and the unavailable spatial grid set S′1 according to the principle that the spatial grids do not overlap, or the spatial grids overlap but the time grids do not overlap.

[0112] In this embodiment, the attached Figure 5 Take the K point in the example, the V associated with the K point t0 is 4754003402640326656, which is compared with V in step 7. t2 , we can see that point K is an available spatial grid and is stored in S1.

[0113] In this embodiment, the attached Figure 5 Take the G point (120.15341, 34.03182, 300) in the example, the V associated with the G point t0 It is 4754003402661298176. Comparing T0 in step 5 and the method in step 7, it can be seen that point G is an unusable spatial grid and is stored in S′1.

[0114] Step 9: For the spatial grid set S1, a spatial "erosion" method is used to calculate the safe interval spatial grid to obtain the actual available spatial three-dimensional grid set S2.

[0115] In this embodiment, the “erosion” function of the available airspace is achieved by “expanding” the unavailable airspace. Taking the “expanding” point G as an example, the spatial grid code of point G is: 3c1260001103b0000000012c17, L s =23 corresponds to the time scale R s is 8 meters, set K s =2, then according to formula (6), the “erosion” threshold of the available space is the “expansion” threshold of the unavailable space TH s =16 meters. The 75 expanded grids at point G are encoded as [3c1258001103b0000000011c17, 3c1260001103b0000000011c17, 3c1268001103b0000000011c17, …, 3c1288001103b0000000011c17, …] and stored in S′2. The same method is used to calculate the other "expanded" grids that cannot be coded using spatial domain grids and store them in S′2. Then, the spatial codes that appear in S′2 are removed from S to form S2.

[0116] Step 10: For the spatial grid set S2, calculate the space A1 corresponding to the grid set, which is the actual available airspace of the dynamic target within the preset range.

[0117] The grid can be converted into a geographic space position by converting the grid code into geographic coordinates. This is a general method and will not be described here.

[0118] This invention spatially encodes a preset airspace and the fixed and dynamically unavailable airspace within it, and associates all spatial codes with temporal codes. By "expanding" the temporal code associated with an unavailable spatial code, a safety gap is reserved while maintaining temporal continuity. By "eroding" the grid code of the available airspace, a safety gap is established between the available and unavailable airspaces, improving airspace utilization while ensuring airspace safety.

[0119] In specific implementations, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium is capable of storing a computer program, and the computer program is executable to run the invention content of a target operation safety airspace planning method based on a space-time grid and some or all steps in each embodiment of the present application when executed by the data processing unit. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), or the like.

[0120] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present application can be realized by means of a computer program and its corresponding general hardware platform. Based on such understanding, the technical solutions in the embodiments of the present application can be embodied in the form of a computer program, i.e., a software product, which can be stored in a storage medium and includes a plurality of instructions for causing a device (which can be a personal computer, a server, a single-chip microcomputer, a MUU, or a network device) containing a data processing unit to execute the method described in each embodiment or some parts of the embodiments of the present application.

[0121] The present application provides a target operation safety airspace planning method based on a space-time grid. There are many methods and approaches to realize the technical solutions, and the above description is only the preferred embodiment of the present application. It should be pointed out that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application. The components not explicitly described in the embodiments can be realized by using existing technologies.

Claims

1. A method for planning target operational safety airspace based on space-time grid, characterized in that: The following steps are involved: Step 1: Set the spatial segmentation level L according to the target size and motion characteristics. s and time segmentation level L t and divide up the whole space and time; Step 2: Based on the target movement range, the airspace A that needs to be analyzed and calculated is demarcated from the geographic space, and the airspace A is divided into spatial subdivision levels L. s , split to form a three-dimensional space grid set S; Step 3: Analyze the fixed unavailable airspace in airspace A and divide this type of airspace into the spatial segmentation level L. s , divided into a three-dimensional space grid set M0; Step 4: Analyze the n dynamically changing unavailable airspaces in airspace A and divide the airspace into different levels according to the spatial segmentation level L. s , which is divided into n three-dimensional space grid sets M1, M2, ..., M corresponding to the airspace n ;M n Represents the three-dimensional space grid set corresponding to the n-th airspace; Step 5: Time-based segmentation level L t , calculate the time it takes for the target to reach each spatial grid in the three-dimensional spatial grid set S, and associate the time vector V for the spatial grid t0 , and calculate M0, M1, M2, ..., M respectively. n The time subdivision grid set T0, T1, T2, ..., T associated with the spatial grid set n ; Step 6: traverse the three-dimensional space grid set S and associate a time vector V with each element in the set t1 , consisting of T0 and T1, T2, ..., T n The elements in each time vector are arranged in ascending order from small to large; Step 7: Use the time dilation method to calculate the time vector V associated with the grid elements. t1 The elements in are expanded to form a new time vector V t2 ; Step 8: Calculate the available spatial grid set S1 and the unavailable spatial grid set S′1 according to the principle that the spatial grids do not overlap, or the spatial grids overlap but the time grids do not overlap; Step 9: For the spatial grid set S1, a spatial erosion method is used to calculate the safe interval spatial grid to obtain the actual available spatial three-dimensional grid set S2; Step 10: For the actual available space grid set S2, calculate the space A1 corresponding to the grid set, which is the actual available airspace of the dynamic target within the preset range.

2. The method according to claim 1, characterized in that Step 2 includes: selecting the starting coordinate point P of the target activity in the geographic coordinate system s (J s , W s , H s ), end coordinate point P e (J e , W e , H e ), forming a rectangular space A, according to L s The corresponding longitude interval ΔJ, latitude interval ΔW, and altitude interval ΔH, from the starting point P s (J s , W s , H s ) to the end point P e (J e , W e , H e ), according to the starting longitude J s To the end longitude J e , starting latitude W s To the end latitude W e , starting height H s To the end height H e The three dimensions are traversed to solve the grid code corresponding to each discrete point to form a three-dimensional space grid set S.

3. The method according to claim 2, characterized in that In step 5, the time it takes for the target to reach each spatial subdivision grid in the three-dimensional spatial grid set S is calculated using the following formula: Where f(t) represents the time it takes for the target to arrive at the grid. In formula (1), formula 1 represents the time calculation method for the active target in a certain spatial grid, l represents the distance from the grid to the initial point of the target, and v represents the target's moving speed; formula 2 represents the time calculation method for the fixed unavailable airspace, t0 represents the start time of the entire planning; formula 3 represents the time calculation method for the dynamic unavailable airspace, t1 represents the start time, and Δt represents the duration.

4. The method according to claim 3, characterized in that In step 5, according to formula (1), the time for the target to reach each spatial subdivision grid in the three-dimensional space grid set S is calculated and stored in the time vector V t0 middle.

5. The method according to claim 4, characterized in that In step 6, the time vector V is constructed using the following method t1 :Traverse the three-dimensional space grid set S, for each spatial subdivision grid s in the three-dimensional space grid set S i , query whether there is a three-dimensional space grid set M i , 0≤i≤n, if it exists, then the corresponding time segmentation grid set T i Time division t in i Take out and store in V in ascending order t1 middle.

6. The method according to claim 5, characterized in that In step 7, let the time vector V t1 The set of elements in is: V t1 =[t0,t1,…,t i ,…,t n ] (2) t in formula (2) i The acquisition method is: traverse the three-dimensional space grid set S, for each space subdivision grid s in S i , check whether it exists in M i If it exists, the corresponding T i Time division t in i Take out and store in V in ascending order t1 middle; Let the time segmentation level L t The corresponding time scale is R t , set the time dilation threshold TH t for: TH t =K t ×R t (3) where K t is an integer; Time vector V t1 The element t in i The specific expansion method is shown in formula (4): Where F(t i ) is the element t i The method to obtain the elements of the expanded vector set is as follows: First, use t i Based on R t For the interval, at t i Insert l before t elements until the inserted element is less than or equal to the previous element t i-1 , then, t i Based on R t For the interval, at t i Then insert K t elements until the inserted element is greater than or equal to the next element t i+1 , and V t1 After each element in is operated according to formula (4), a new time vector V is formed. t2 .

7. The method according to claim 6, characterized in that Step 8 includes: traversing the three-dimensional space grid set S, for each spatial subdivision grid s in the three-dimensional space grid set S i , remove s i The corresponding V t0 and V t2 , V t0 Indicates that the target reaches the grid s i Time, V t2 Represents the unavailable time set; then traverse V t0 Each element t in i , judge t i Is there a V t2 If it does not exist, then s i Store it in S1, otherwise store it in the unavailable spatial grid set S′1, thereby obtaining the available spatial grid set S1 and the unavailable spatial grid set S′1.

8. The method according to claim 7, characterized in that Step 9 includes: It is known that the relationship among S, S1 and S′1 is as shown in (5): Among them, S1 represents the available spatial grid code set, s 1i is an element in the S1 set; S′1 represents the unavailable spatial grid code set, s′ 1i is an element in the S′1 set.

9. The method according to claim 8, characterized in that In step 9, let the spatial subdivision level L s The corresponding spatial scale is R s , set the spatial corrosion threshold TH s for: TH s =K s ×R s (6) where K s is an integer; The element s′ in the three-dimensional space grid S′1 1i The specific expansion method is shown in formula (7): Where S′2(i) represents s′ 1i The grid set after expansion in the longitude, latitude and altitude directions, I represents the expansion interval in the longitude direction, J represents the expansion interval in the latitude direction, and K represents the expansion interval in the altitude direction.

10. The method according to claim 9, characterized in that In step 9, first, in three-dimensional space, 1i As the center, it expands to form a side length of (2×K s +1)×R s cube, increase (2×K s +1) 3 mesh; then, (2×K s +1) 3 The grids are stored in the new grid set S′2 to form a new unavailable spatial grid set S′2; finally, the grids of S′2 are removed from the three-dimensional spatial grid set S to form the actual available spatial three-dimensional grid set S2.

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