Satellite Earth observation path planning methods, devices, equipment and storage media

Abstract

This invention provides a satellite Earth observation path planning method, apparatus, device, and storage medium, comprising: acquiring the Earth orbit, swath width, and observation task of the satellite to be performed; dividing the expected observation ground area into a two-dimensional grid map containing multiple uniform squares; characterizing the observation requirements of the two-dimensional grid map; stacking the two-dimensional grid map after the observation requirements are characterized according to the temporal changes of the Earth orbit to obtain a three-dimensional spatiotemporal grid; searching for path observation points based on the three-dimensional spatiotemporal grid to obtain a target path observation point set that satisfies the minimization of a pre-constructed optimization objective function; and performing path transformation on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. This invention extends two-dimensional path planning to path planning on a three-dimensional spatiotemporal grid, effectively simplifying the processing of dynamic time-varying constraints and improving the efficiency of satellite Earth observation path planning.

Description

Technical Field

[0001] This invention relates to the field of satellite observation technology, and in particular to a satellite Earth observation path planning method, apparatus, equipment, and storage medium. Background Technology

[0002] Remote sensing satellites provide humanity with a broad and comprehensive view for understanding the Earth and monitoring ground events, playing a vital role in fields such as agricultural production, resource exploration, mapping, and disaster relief. With the simultaneous growth in the number of satellites and the scale of ground observation needs, satellite mission planning and management present significant challenges. Satellite mission planning, in particular, involves using specific scheduling algorithms to allocate a series of observation tasks to satellites according to an optimal plan, ensuring timely fulfillment of observation needs and improving satellite resource utilization.

[0003] Currently, satellite Earth observation path planning is a key problem in satellite mission planning. Specifically, it involves using path planning algorithms to solve for the location and time trajectory of observation points during a series of satellite observation tasks. Existing technologies perform path planning on a two-dimensional spatial grid map of satellite Earth observation. Due to the dynamic nature of observation mission requirements and the influence of satellite orbital motion, the satellite Earth observation path planning problem is subject to strong time-varying constraints such as satellite-to-ground visibility and changes in observation requirements. Each time the grid is expanded, it is necessary to perform temporary calculations and judgments on the satellite-to-ground visibility of the new grid location, resulting in a large amount of unnecessary computational and time consumption, which further affects the efficiency of satellite Earth observation path planning. Summary of the Invention

[0004] In view of this, the present invention aims to propose a satellite Earth observation path planning method, apparatus, equipment and storage medium to solve the problem that the satellite Earth observation path planning problem is subject to strong time-varying constraints such as satellite-to-ground visibility, which leads to a large amount of unnecessary computing power and time consumption affecting the efficiency of satellite Earth observation path planning.

[0005] According to a first aspect of the present invention, a satellite Earth observation path planning method is provided, the method comprising:

[0006] Obtain the Earth orbit, image swath width, and observation task of the satellite to be performed;

[0007] Based on the Earth orbit and the shooting swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares, and the observation requirements of the two-dimensional grid map are characterized according to the observation task.

[0008] Based on the temporal changes of the Earth orbit, the two-dimensional grid diagrams characterized by the observation requirements are stacked in chronological order to obtain a three-dimensional spatiotemporal grid.

[0009] Based on the three-dimensional spatiotemporal grid, a path observation point search is performed to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function;

[0010] The target path observation point set is transformed to obtain the optimal Earth observation path for the satellite to perform the observation task.

[0011] Optionally, the step of dividing the expected observation ground area into a two-dimensional grid map containing multiple uniform squares based on the Earth orbit and the imaging swath width, and characterizing the observation requirements of the two-dimensional grid map according to the observation task, includes:

[0012] Based on the Earth orbit, determine the maximum observation area of ​​the satellite at each sub-satellite point, and summarize the maximum observation areas of each sub-satellite point to obtain the expected ground observation area;

[0013] Based on the shooting width, the side length of the square grid to be divided is calculated, and the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares using the side length of the square grid.

[0014] The characterization parameters are determined based on the task to be observed, and the characterization parameters are used to characterize the observation requirements of the two-dimensional grid diagram.

[0015] Optionally, the step of determining the characterization parameters based on the task to be observed, and using the characterization parameters to characterize the observation requirements of the two-dimensional grid map, includes:

[0016] The geographical latitude and longitude of the target point and the urgency factor of the observation requirement are extracted from the task to be observed.

[0017] Based on the actual geographical latitude and longitude of the center of each square grid in the two-dimensional grid diagram, the geographical latitude and longitude of the target point, and the observation urgency factor, characterization parameters are generated; wherein, the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation urgency factor;

[0018] The observation requirements are characterized using the aforementioned characterization parameters on the square grid in the two-dimensional grid diagram.

[0019] Optionally, the step of stacking the two-dimensional grid map characterized by the observation requirements according to the temporal changes of the Earth orbit to obtain a three-dimensional spatiotemporal grid includes:

[0020] Based on the temporal changes in the Earth orbit, the satellite's visibility to the square grid in the two-dimensional grid diagram is determined;

[0021] Based on the visibility of the square grid, the square grids in the two-dimensional grid diagram after the observation requirements are characterized are stacked in chronological order to obtain a three-dimensional spatiotemporal grid, which is represented as follows:

[0022] ST(x,y,t)=A(x,y,t)κ(x,y)

[0023] in, M represents the number of grid cells in the spatial grid size, K represents the time sequence number of the observation mission endpoint, x,y∈{0,1,2,...,M}, t∈{0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ, where A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the observation urgency factor.

[0024] Optionally, the step of searching for path observation points based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfies the minimization of a pre-constructed optimization objective function includes:

[0025] The transfer benefits and transfer costs of satellites between observed grid nodes are obtained in advance, and an optimization objective function is constructed using the transfer benefits and the transfer costs;

[0026] The optimization objective function is minimized as the search objective. Path search is performed on each grid node in a forward expansion manner along the time dimension to obtain the target path observation point set.

[0027] Optionally, the step of minimizing the optimization objective function as the search objective, and performing path search on each grid node in a forward expansion manner along the time dimension to obtain the target path observation point set, includes:

[0028] Determine the starting and ending grids, and define the grid that minimizes the optimization objective function as the expanded grid;

[0029] Starting from the initial grid, the extended grid is traversed and searched in a forward expansion manner along the time dimension, and the visibility of the extended grid is obtained;

[0030] If the extended grid is visible and the optimization objective function at the extended grid is minimized, then the extended grid is stored in a preset path observation point set;

[0031] If the extended grid coincides with the endpoint grid, the preset path observation point set is updated to the target path observation point set.

[0032] Optionally, the transfer benefits and transfer costs of satellites between observed grid nodes are obtained in advance, and an optimization objective function is constructed using the transfer benefits and transfer costs. The optimization objective function is expressed as:

[0033]

[0034] G i,i+1 =βA(x i+1 ,y i+1 )k(x i+1 ,y i+1 )-C i,i+1

[0035] in, Represents the state vector of a grid node. The actual cost from the starting grid node to the current grid node. G is the estimated cost from the current grid node to the target grid node. i，i+1 G represents the transfer reward from the current grid node to the target grid node, β represents the grid task reward factor, and G represents the transfer reward from the current grid node to the target grid node. i，i+1 This represents the transfer cost from the current grid node to the target grid node.

[0036] According to a second aspect of the present invention, a satellite Earth observation path planning device is provided, the device comprising:

[0037] The information acquisition module is used to acquire the Earth orbit of the satellite to be executed, the swath width of the image, and the task to be observed.

[0038] The observation requirement characterization module is used to divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares according to the Earth orbit and the shooting swath width, and to characterize the observation requirements of the two-dimensional grid map according to the observation task.

[0039] The three-dimensional spatiotemporal grid module is used to stack the two-dimensional grid map characterized by the observation requirements in chronological order according to the temporal changes of the orbit around the Earth to obtain a three-dimensional spatiotemporal grid.

[0040] The path search module is used to search for path observation points based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function.

[0041] The path conversion module is used to convert the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task.

[0042] According to another aspect of the present invention, an electronic device is also provided, comprising:

[0043] processor;

[0044] Memory used to store the processor's executable instructions;

[0045] The processor is configured to execute the instructions to implement the satellite Earth observation path planning method described above.

[0046] According to another aspect of the present invention, a readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the satellite Earth observation path planning method as described above.

[0047] The satellite Earth observation path planning method provided in this invention obtains the Earth orbit, swath width, and observation task of the satellite to be performed. Based on the Earth orbit and swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares. Then, the observation requirements of the two-dimensional grid map are characterized according to the observation task. Based on the temporal changes of the Earth orbit, the two-dimensional grid map after the observation requirements are characterized is stacked in time order to obtain a three-dimensional spatiotemporal grid. Path observation points are searched based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function. Path transformation is performed on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. This invention extends the time dimension into a supplementary dimension of the path planning space, transforming the dynamic satellite-to-ground visibility constraints that change regularly over time into static constraints. This expands two-dimensional path planning into path planning on a three-dimensional spatiotemporal grid, and constructs a path search algorithm suitable for the three-dimensional spatiotemporal grid. This yields the optimal Earth observation path for the satellite to perform its observation mission, achieving efficient processing of time-varying satellite-to-ground visibility constraints, effectively simplifying the processing of dynamic time-varying constraints, and further improving the efficiency of satellite Earth observation path planning.

[0048] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0049] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0050] Figure 1This is a flowchart of the steps of a satellite Earth observation path planning method provided in an embodiment of the present invention;

[0051] Figure 2 yes Figure 1 A flowchart of step 102 in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0052] Figure 3 yes Figure 1 A flowchart of step 103 in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0053] Figure 4 yes Figure 1 A flowchart of step 104 in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0054] Figure 5 This is a schematic diagram of the square grid of the satellite in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0055] Figure 6 This is a schematic diagram illustrating the observation requirements in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0056] Figure 7 This is a schematic diagram of the observation task transfer cost in the satellite Earth observation path planning method provided in this embodiment of the invention;

[0057] Figure 8 This is a schematic diagram of the structure of a satellite Earth observation path planning device provided in an embodiment of the present invention;

[0058] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of the present invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0060] Reference Figure 1 The diagram illustrates a flowchart of the satellite Earth observation path planning method provided by an embodiment of the present invention. The method may include:

[0061] Step 101: Obtain the Earth orbit of the satellite to be executed, the swath width of the image, and the task to be observed.

[0062] In this embodiment of the invention, addressing the need for satellite Earth observation path planning, and to resolve the issue that satellite Earth observation path planning is subject to strong time-varying constraints such as satellite-to-ground visibility and changing observation requirements, the visibility of the satellite-to-ground at the new grid location needs to be temporarily calculated and judged each time the grid is expanded, resulting in a large amount of unnecessary computing power and time consumption, further affecting the efficiency of satellite Earth observation path planning, this embodiment expands the time dimension into a supplementary dimension of the path planning space, extending two-dimensional spatial path planning into path planning on a three-dimensional spatiotemporal grid. This transforms the time-varying satellite-to-ground visibility constraints into static constraints, realizing satellite Earth observation path planning based on a three-dimensional spatiotemporal grid, effectively simplifying the handling of dynamic time-varying constraints and improving the efficiency of satellite Earth observation path planning.

[0063] Specifically, in this embodiment, the Earth orbit is the path of the satellite around the Earth. The Earth orbit includes parameters such as orbital altitude and orbital inclination, which directly affect the satellite's observation capabilities and coverage. The Earth orbit determines the satellite's nadir trajectory and coverage. The swath width is the width of the ground that the satellite sensor can cover in a single image. The observation task is the specific target that the satellite performs. The observation task includes observation requirements and task priority. The task priority is represented by the urgency factor of the observation requirements of each target location in a certain observation task.

[0064] Step 102: Based on the Earth orbit and the imaging swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares, and the observation requirements of the two-dimensional grid map are characterized according to the observation task.

[0065] In this embodiment of the invention, based on the Earth orbit and the imaging swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares. Specifically, based on the Earth orbit of the satellite to be performed, that is, the satellite's motion path, the maximum observation area of ​​the satellite at each sub-satellite point can be determined on the satellite's motion path. The maximum observation areas of each sub-satellite point are integrated to obtain all areas that the satellite can observe when it is orbiting the Earth, i.e., the expected observation ground area. Here, the sub-satellite point is the point on the Earth's surface directly below the satellite during its operation, and it is also the vertical projection point between the satellite and the Earth's surface. It is usually represented by latitude and longitude coordinates. The trajectory of the sub-satellite point is the path formed on the Earth's surface when the satellite is orbiting the Earth.

[0066] In this embodiment, based on the satellite's swath width, the expected observation area is divided into a two-dimensional grid map containing multiple uniform square grids of the same size. Each square grid can be completely covered by a single image captured by the satellite payload. Figure 5 The diagram shows a square grid of a satellite in the satellite Earth observation path planning method provided by an embodiment of the present invention. In the two-dimensional grid diagram, the side length of each square grid is the side length of the inscribed square of the circle whose diameter is equal to the width of the shooting swath.

[0067] It should be noted that a satellite payload is a device or instrument carried on a satellite to perform a specific mission. It is a core component of the satellite and directly determines the satellite's function and purpose. In this embodiment, depending on the mission requirements, the satellite payload may be an optical camera, radar, communication equipment, scientific instruments, etc., and no specific limitation is made here.

[0068] Specifically, observation demand characterization refers to the process of uniformly representing observation demands from multiple industries and directions onto a grid diagram. A predefined observation demand urgency factor for a specific task to be observed is used. The larger the value of the observation demand urgency factor, the more urgent the need for the corresponding task to be observed, i.e., the higher the task priority. In this embodiment, the observation demand characterization of the two-dimensional grid diagram based on the task to be observed specifically involves extracting the geographic latitude and longitude of the target point and the observation demand urgency factor from the task to be observed. The geographic latitude and longitude of the target point is the endpoint location of the task to be observed. Based on the actual geographic latitude and longitude of the center of each square grid in the two-dimensional grid diagram, the geographic latitude and longitude of the target point, and the observation demand urgency factor, characterization parameters are generated. These characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation demand urgency factor. Thus, the observation demand is characterized for the square grids in the two-dimensional grid diagram using these characterization parameters.

[0069] Step 103: Based on the temporal changes of the Earth orbit, stack the two-dimensional grid diagrams characterized by the observation requirements in chronological order to obtain a three-dimensional spatiotemporal grid.

[0070] In this embodiment of the invention, the three-dimensional spatiotemporal grid is formed by adding a time dimension to a two-dimensional spatial grid, creating a three-dimensional data structure. Its three dimensions are: spatial dimension (longitude and latitude), used to represent the location of ground regions; and temporal dimension, used to represent the observation opportunities of satellites at different points in time. Therefore, by stacking the two-dimensional grid diagrams characterized according to the temporal changes in Earth orbit, a three-dimensional spatiotemporal grid can be obtained. Each grid contains an observation demand characterization, with characterization parameters including the position coordinates of the square grid on the two-dimensional plane and an observation demand urgency factor. This allows for the effective combination of spatial and temporal information after the two-dimensional grid diagram is expanded into a three-dimensional spatiotemporal grid.

[0071] Specifically, when expanding the spatiotemporal grid based on the square grid characterized by observation requirements, considering the satellite's orbital motion and limited payload sensing range, only some grids are visible at a certain moment. Whether the observation target has the opportunity to be observed is constrained by the time-varying satellite-to-ground visibility. Satellite-to-ground visibility is time-varying but predictable. Therefore, in this embodiment, a binarized variable is used to represent the satellite's visibility to the square grid at a certain moment. When the satellite is not visible to the square grid, the binarized variable of visibility takes the value of 0. When the satellite is visible to the square grid, the binarized variable of visibility takes the value of 1. After determining the visible square grids, the square grids are stacked in time order to obtain a three-dimensional spatiotemporal grid.

[0072] Step 104: Search for path observation points based on a three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function.

[0073] In this embodiment of the invention, considering the transfer cost and benefits of the satellite in the observation mission, there is an optimal path in the payload maneuver process. The transfer benefits and transfer costs of the satellite between the observed grid nodes are obtained in advance. An optimization objective function is constructed using the transfer benefits and transfer costs. Path observation points are searched based on a three-dimensional spatiotemporal grid to find the path observation points that minimize the optimization objective function, thus obtaining a set of target path observation points that satisfy the minimization of the pre-constructed optimization objective function.

[0074] In this embodiment, for the task grid observation sequence planning problem, the ST-A* algorithm is constructed, which is an optimization algorithm obtained by extending the A* algorithm to three-dimensional spatiotemporal space. Considering the need to carry out path planning on a three-dimensional spatiotemporal grid, the A* algorithm is extended to three-dimensional spatiotemporal space to construct a spatiotemporal A* algorithm, abbreviated as ST-A* algorithm. The ST-A* algorithm is essentially a heuristic search algorithm that expands the search nodes with the goal of minimizing the optimization objective function, thereby obtaining a set of target path observation points that satisfy the minimization of the pre-constructed optimization objective function.

[0075] Step 105: Perform path transformation on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task.

[0076] In this embodiment of the invention, after path observation point search, a target path observation point set that minimizes the optimization objective function can be obtained. The observation points in the target path observation point set are arranged in time series. The optimal sequence of satellite imagery of the grid from time 0 to time K is the optimal Earth observation path observation point set, denoted as... Each observation point represents the coordinates of a square grid within a corresponding three-dimensional spatiotemporal grid.

[0077] Specifically, a path transformation is performed on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. When performing grid imaging tasks sequentially, the latitude and longitude trajectory of the satellite observation points is determined by the square grid coordinates (x, y). The execution time of the satellite observation points is consistent with the grid time coordinate t, and the actual time at time t is recorded as T. t Let the latitude and longitude of the satellite observation point at time t be denoted as The spatiotemporal trajectory of the satellite observation point, i.e., the optimal Earth observation path, can be obtained by transforming each element according to the following formula:

[0078]

[0079] The satellite Earth observation path planning method provided in this invention obtains the Earth orbit, swath width, and observation task of the satellite to be performed. Based on the Earth orbit and swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares. Then, the observation requirements of the two-dimensional grid map are characterized according to the observation task. Based on the temporal changes of the Earth orbit, the two-dimensional grid map after the observation requirements are characterized is stacked in time order to obtain a three-dimensional spatiotemporal grid. Path observation points are searched based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function. Path transformation is performed on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. This invention extends the time dimension into a supplementary dimension of the path planning space, transforming the dynamic satellite-to-ground visibility constraints that change regularly over time into static constraints. This expands two-dimensional path planning into path planning on a three-dimensional spatiotemporal grid, and constructs a path search algorithm suitable for the three-dimensional spatiotemporal grid. This yields the optimal Earth observation path for the satellite to perform its observation mission, achieving efficient processing of time-varying satellite-to-ground visibility constraints, effectively simplifying the processing of dynamic time-varying constraints, and further improving the efficiency of satellite Earth observation path planning.

[0080] Furthermore, refer to Figure 2 , showed Figure 1 A flowchart of step 102 in a satellite Earth observation path planning method is provided. This method is basically the same as the satellite Earth observation path planning method provided in the first embodiment of the present invention. Step 102 may include:

[0081] Step 1021: Determine the maximum observation area of ​​the satellite to be performed at each sub-satellite point based on its orbit around the Earth, and summarize the maximum observation areas of each sub-satellite point to obtain the expected ground observation area.

[0082] Step 1022: Calculate the side length of the square grid to be divided based on the shooting width, and use the side length of the square grid to divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares.

[0083] Step 1023: Determine the characterization parameters based on the task to be observed, and use the characterization parameters to characterize the observation requirements of the two-dimensional grid map.

[0084] In this embodiment of the invention, reference is made to Figure 6 This diagram illustrates the observation requirement characterization in the satellite Earth observation path planning method provided by an embodiment of the present invention. Based on the satellite's flight direction, the maximum observation area of ​​the satellite to perform the mission at each sub-satellite point is determined. Specifically, based on the satellite's orbital parameters such as orbital altitude, orbital type, and sensor field of view, the maximum ground coverage width of a single satellite observation is obtained, which is the maximum observation area of ​​the satellite at each sub-satellite point. For each sub-satellite point, its maximum observation area is determined to be a circular area. The maximum observation areas of each sub-satellite point are superimposed to obtain the ground area that the satellite is expected to cover within a preset time period, which is the expected ground observation area.

[0085] Specifically, based on the expected observation area, a two-dimensional grid map is first obtained. The side length of the square grid to be divided needs to be calculated according to the shooting swath width. Using the side length of the square grid, the expected observation area is divided into a two-dimensional grid map containing multiple uniform squares. The side length of each square grid in the two-dimensional grid map is [value missing], and the side length of the inscribed square of the circle with a diameter equal to the shooting swath width is [value missing]. The method for calculating the side length of the square grid is as follows:

[0086]

[0087] Where d represents the swath width of the satellite image, and l represents the side length of the square grid.

[0088] In this embodiment, characterization parameters are determined based on the task to be observed, and the observation demand is characterized by the characterization parameters on the two-dimensional grid map. First, the geographic latitude and longitude of the target point and the observation demand urgency factor are extracted from the task to be observed. Based on the actual geographic latitude and longitude of the center of each square grid in the two-dimensional grid map, the geographic latitude and longitude of the target point, and the observation demand urgency factor, characterization parameters are generated. The characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation demand urgency factor. Thus, the observation demand is characterized by the characterization parameters on the square grid in the two-dimensional grid map.

[0089] This invention divides the expected observation ground area into a two-dimensional grid map and characterizes the observation requirements. This facilitates the expansion of the two-dimensional grid map into a three-dimensional spatiotemporal grid map based on the square grid after the observation requirements are characterized, thereby realizing the expansion of two-dimensional path planning into path planning on a three-dimensional spatiotemporal grid.

[0090] Specifically, step 1023 determines the characterization parameters based on the task to be observed, and uses these parameters to characterize the observation requirements of the two-dimensional grid map. This may include the following steps:

[0091] Sub-step 01: Extract the geographical latitude and longitude of the target point and the urgency factor of the observation requirement from the task to be observed;

[0092] Sub-step 02: Generate characterization parameters based on the actual geographic latitude and longitude of the center of each square grid in the two-dimensional grid diagram, the geographic latitude and longitude of the target point, and the observation urgency factor; wherein, the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation urgency factor.

[0093] Sub-step 03 involves using characterization parameters to characterize the observation requirements of the square grid in the two-dimensional grid diagram.

[0094] It should be noted that in the above steps, when characterizing the observation requirements for each square grid in the two-dimensional grid diagram, the geographic latitude and longitude of the target point and the corresponding observation requirement urgency factor are extracted from the observation task. The geographic latitude and longitude of the target point are used to represent the specific location of the observation endpoint of the observation task. Characterization parameters are generated based on the actual geographic latitude and longitude of the center of each square grid, the geographic latitude and longitude of the target point, and the observation requirement urgency factor. The observation requirements for the corresponding square grid are then characterized based on the characterization parameters.

[0095] Specifically, the characterization parameters include three parameters, where k represents the urgency factor of observation demand, and x and y represent the position coordinates of the square grid on the two-dimensional plane, which are calculated using the following formula:

[0096]

[0097] Where δ represents the actual surface distance corresponding to a unit of latitude and longitude, and its value is 111.32 km / °. This represents the actual geographic latitude and longitude corresponding to the center of the square grid. This represents the geographic latitude and longitude of the target point, round() represents the rounding function, and l represents the side length of the square grid.

[0098] Specifically, the above formula can be used to obtain the observation demand characterization parameters for each square grid, and these characterization parameters can be used as parameters representing the position coordinates of the square grid on the two-dimensional plane. Combined with the observation demand urgency factor, the observation demand of the corresponding square grid can be characterized.

[0099] This invention improves the accuracy of extended three-dimensional spatiotemporal grids by determining the position coordinate parameters of the two-dimensional grid and the urgency factor of observation needs, thereby achieving an accurate representation of the observation needs of square grids.

[0100] Furthermore, refer to Figure 3 , showed Figure 1 A flowchart of step 103 in a satellite Earth observation path planning method is provided. This method is basically the same as the satellite Earth observation path planning method provided in the first embodiment of the present invention. Step 103 may include:

[0101] Step 1031: Determine the satellite's visibility of the square grid in the two-dimensional grid diagram based on the temporal changes of the Earth orbit.

[0102] Step 1032: Based on the visibility of the square grid, stack the square grids in the two-dimensional grid map after the observation requirements are characterized in time order to obtain a three-dimensional spatiotemporal grid.

[0103] The three-dimensional spatiotemporal grid is represented as follows:

[0104] ST(x,y,t)=A(x,y,t)κ(x,y)

[0105] in, M represents the number of grid cells in the spatial grid size, K represents the time sequence number of the observation mission endpoint, x,y∈{0,1,2,...,M}, t∈{0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ, where A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the observation urgency factor.

[0106] It should be noted that in this embodiment of the invention, when expanding the spatiotemporal grid based on the two-dimensional grid map characterized by observation requirements in the spatiotemporal dimension, considering the satellite's orbital motion and the limited payload sensing range, only a portion of the grid is visible at a certain moment. This is due to the constraint of time-varying satellite-to-ground visibility; the visible area on the ground at a certain moment will change with time and satellite orbital motion. Since satellite-to-ground visibility is time-varying but predictable, in this embodiment, a binary variable A is used to represent the satellite's visibility of the square grid (x,y) at a certain moment. When the satellite is not visible to the square grid (x,y), A takes a value of 0; when the satellite is visible to the square grid (x,y), A takes a value of 1. The square grids are then stacked in time t order to obtain a three-dimensional spatiotemporal grid with horizontal and vertical coordinates of x, y, and t, respectively. The brightness of each grid is A(x,y,t)κ(x,y). In this embodiment, a three-dimensional matrix will be constructed. A three-dimensional spatiotemporal grid is stored, where M represents the number of grid cells in the spatial grid size and K represents the time sequence number of the observation mission endpoint. Since the visibility of the grid and the satellite is predictable, the three-dimensional spatiotemporal grid can be pre-constructed before the satellite observation path planning. It is assumed that the total time length of satellite platform and payload attitude adjustment, attitude stabilization and observation imaging is fixed for each observation mission, denoted as Δt. The unit length of the spatiotemporal grid in the t dimension is Δt, and the unit length in the x and y dimensions is l.

[0107] This invention extends two-dimensional path planning into a three-dimensional spatiotemporal grid by expanding the time dimension into a supplementary dimension of the path planning space, transforming the dynamic space-to-ground visibility constraint that changes regularly over time into a static constraint.

[0108] Furthermore, refer to Figure 4 , showed Figure 1 A flowchart of step 104 in a satellite Earth observation path planning method is provided. This method is basically the same as the satellite Earth observation path planning method provided in the first embodiment of the present invention. Step 104 may include:

[0109] Step 1041: Pre-obtain the transfer benefits and transfer costs of the satellite between the observed grid nodes, and construct an optimization objective function using the transfer benefits and transfer costs;

[0110] Step 1042: Minimize the optimization objective function as the search objective, and perform path search on each grid node in a forward expansion manner along the time dimension to obtain the target path observation point set.

[0111] It should be noted that in this embodiment of the invention, the transfer benefits and transfer costs of the satellite between the observed grid nodes are obtained in advance, and an optimization objective function is constructed using the transfer benefits and transfer costs. When searching for the optimal Earth observation path based on a three-dimensional spatiotemporal grid, it is necessary to construct an objective function. In this embodiment, the objective function is constructed based on the transfer benefits and transfer costs of the satellite observation point migrating from one grid node to another.

[0112] Specifically, first consider the cost of switching observation tasks. Suppose the satellite payload observes the region (x1, y1) at time t1 and the grid (x2, y2) at time t2. From time t1 to t2, the satellite payload observation point moves from (x1, y1) to (x2, y2). Considering limitations such as energy consumption and component wear, there exists an optimal path for the payload maneuver. Simultaneously, the satellite's orbital motion will bring certain benefits to the maneuver cost of switching observation tasks. Considering the benefits of observation tasks, the benefit obtained by each grid upon completion of observation is related to the urgency of the grid's observation demand. Therefore, the task benefit of the observation grid can be calculated as βAκ, where β is the grid task benefit factor. The constructed optimization objective function is denoted as:

[0113]

[0114] in, Represents the node state vector. This is the cost function, used to represent the cost starting from the initial node. To the current node The actual cost This is a heuristic function used to represent the function starting from the current node. To the target node The estimated cost.

[0115] Therefore, minimizing the optimization objective function is determined as the search objective, and path search is performed on each grid node in a forward expansion manner in the time dimension to obtain the set of observation points for the target path.

[0116] Specifically, step 1042 defines minimizing the objective function as the search objective, and performs path search on each grid node in a forward expansion manner along the time dimension to obtain the target path observation point set, which may include:

[0117] Sub-step 01: Determine the starting and ending meshes, and identify the mesh that minimizes the objective function as the expanded mesh;

[0118] Sub-step 02: Starting from the initial grid, traverse and search the extended grid in a forward expansion manner along the time dimension, and obtain the visibility of the extended grid;

[0119] Sub-step 03: If the expanded grid is visible and the optimization objective function at the expanded grid is minimized, then the expanded grid is stored in the preset path observation point set;

[0120] Sub-step 04: If the extended grid and the endpoint grid overlap, update the preset path observation point set to the target path observation point set.

[0121] It should be noted that in this embodiment of the invention, minimizing the objective function is determined as the search objective. Path searches are performed on each grid node in a forward expansion manner along the time dimension to obtain the target path observation point set. The ST-A* algorithm is then constructed, which is an optimization algorithm obtained by extending the A* algorithm to three-dimensional spatiotemporal space. Considering the need for path planning on a three-dimensional spatiotemporal grid, the A* algorithm is extended to three-dimensional spatiotemporal space to construct a spatiotemporal A* algorithm, abbreviated as ST-A* algorithm. The ST-A* algorithm is essentially a heuristic search algorithm that expands the search nodes with the goal of minimizing the objective evaluation function.

[0122] Specifically, when performing path search within a 3D spatiotemporal grid ST using the ST-A* algorithm, the node state vector... That is, (x,y,t). Indicates the starting grid, and has Indicates the endpoint grid, i.e. Depend on Expand to At this time, nodes expand in two spatial dimensions, i.e., a two-dimensional plane, with a step size of l. At a certain node, it can move to 9 grid positions adjacent to the current node in the dimension (including remaining stationary). Therefore:

[0123]

[0124] In the time dimension, the grid nodes expand with a step size of Δt, but can only grow in a forward direction strictly in time. That is, in the time dimension, t can only expand by "+1" and cannot remain unchanged or decrease. Therefore, starting from the initial grid, the expanded grid is traversed and searched in a forward expansion manner in the time dimension, and the visibility of the expanded grid is obtained. If the expanded grid is visible and the optimization objective function at the expanded grid is minimized, the expanded grid is stored in the preset path observation point set. If the expanded grid coincides with the endpoint grid, the preset path observation point set is updated to the target path observation point set.

[0125] For example, in this embodiment, when performing path search based on ST-A*, an OpenSet set and a CloseSet set are used to store the grid nodes to be explored and the grid nodes that have already been explored, respectively. The specific algorithm flow is as follows:

[0126] S1, Algorithm Initialization: Calculation and the starting node Place it in OpenSet.

[0127] S2, select in OpenSet The node with the smallest value As the current expansion node, and will Move it to the CloseSet collection.

[0128] S3, along the direction of increasing t dimension Any new node around Perform a traversal search, where t new =t+1, and execute according to the following rules:

[0129] If A(x) new ,y new ) = 0, indicating If its visibility is invisible, then If the node is unreachable, abandon it; otherwise... If it is a reachable node, perform the following judgment: If If it is not included in the OpenSet collection, then calculate Optimize the objective function value and Add to OpenSet collection, As The parent node; if The node already exists in the OpenSet collection; let it be denoted as... And judge and If the function value of a new reachable node is greater than or equal to the function value of an existing node in the set, then that node is discarded; otherwise, the value is determined by the set's size. replace and with As The parent node.

[0130] S4. If OpenSet is empty, return "No feasible solution" and terminate the algorithm. If OpenSet is not empty, proceed according to the following rules: If... The optimal path has been found, from The optimal path is obtained by tracing back the parent nodes in reverse order; if Then continue repeating steps 2-3.

[0131] Specifically, step 1041 pre-obtains the transfer benefits and costs of satellites between observed grid nodes, and constructs an optimization objective function using these benefits and costs. The optimization objective function is expressed as:

[0132]

[0133] G i,i+1 =βA(x i+1 ,y i+1 )k(x i+1 ,yi+1 )-C i,i+1

[0134] in, Represents the state vector of a grid node. The actual cost from the starting grid node to the current grid node. G is the estimated cost from the current grid node to the target grid node. i，i+1 G represents the transfer reward from the current grid node to the target grid node, β represents the grid task reward factor, and G represents the transfer reward from the current grid node to the target grid node. i，i+1 This represents the transfer cost from the current grid node to the target grid node.

[0135] In this embodiment of the invention, by arrive subpath Cost function and heuristic functions They are constructed as follows:

[0136]

[0137] Easy to prove, and The optimal conditions for satisfying the A* algorithm are:

[0138]

[0139] in, To start from the current node Reach the destination task grid The actual optimal objective evaluation function.

[0140] In this embodiment, refer to Figure 7 This diagram illustrates the observation task transfer cost in the satellite Earth observation path planning method provided by an embodiment of the present invention. The transfer cost is characterized by the straight-line distance between two observation points, denoted as . in, It is easy to see that the satellite's orbital motion will bring certain benefits to the maneuvering costs of switching observation tasks. Assume that the direction vector of the satellite's nadir trajectory falling on the grid coordinate system is... satisfy The gain in maneuver distance can be expressed as and The vector product can be used to calculate the transfer cost of moving the satellite payload observation point from (x1, y1) to (x2, y2):

[0141]

[0142] in, α represents the benefit factor of orbital motion, which is used to adjust the proportion of the impact of orbital motion on costs; α < 0.

[0143] Considering the benefits of observation tasks, the benefit gained by each grid upon completing an observation is related to the urgency of the grid's observation needs. The task benefit of an observation grid can be calculated as βAκ, where β is the grid task benefit factor. β>0 is used to adjust the proportion of grid task benefits in the overall benefit function. Considering task transfer costs and grid task benefits, the transfer benefit from moving from (x1,y1) to (x2,y2) is constructed and denoted as G. 1,2 Then we have:

[0144] G 1,2 =βA(x2,y2)κ(x2,y2)-C 1,2

[0145] Among them, G 1,2 C represents the transfer reward from square grid (x1, y1) to square grid (x2, y2), β represents the grid task reward factor, and C represents the transfer reward from square grid (x1, y1) to square grid (x2, y2). 1,2 This represents the transfer cost from square grid (x1, y1) to square grid (x2, y2).

[0146] Based on the extended three-dimensional spatiotemporal grid, this invention constructs a path search algorithm suitable for the three-dimensional spatiotemporal grid, thereby obtaining the optimal Earth observation path for the satellite to perform the observation task, and realizing efficient processing of time-varying satellite-to-ground visibility constraints.

[0147] Reference Figure 8 The diagram shows a structural schematic of a satellite Earth observation path planning device 200 provided in an embodiment of the present invention. The device includes:

[0148] The information acquisition module 201 is used to acquire the Earth orbit, image swath width, and observation task of the satellite to be performed.

[0149] The observation requirement characterization module 202 is used to divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares according to the Earth orbit and the shooting swath width, and to characterize the observation requirements of the two-dimensional grid map according to the observation task.

[0150] The three-dimensional spatiotemporal grid module 203 is used to stack the two-dimensional grid map characterized by the observation requirements in time order according to the temporal changes of the orbit around the Earth to obtain a three-dimensional spatiotemporal grid.

[0151] Path search module 204 is used to search for path observation points based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function;

[0152] The path conversion module 205 is used to perform path conversion on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task.

[0153] Furthermore, the observation requirement characterization module 202 includes:

[0154] The regional submodule is used to determine the maximum observation area of ​​the satellite to be performed at each sub-satellite point based on the Earth orbit, and to summarize the maximum observation areas of each sub-satellite point to obtain the expected ground observation area.

[0155] The segmentation submodule is used to calculate the side length of the square grid to be segmented based on the shooting width, and to use the side length of the square grid to divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares;

[0156] The characterization submodule is used to determine characterization parameters based on the task to be observed, and to characterize the observation requirements of the two-dimensional grid map using the characterization parameters.

[0157] Furthermore, the characterization submodule includes:

[0158] The extraction unit is used to extract the geographic latitude and longitude of the target point and the urgency factor of the observation requirement in the observation task.

[0159] The generation unit is used to generate characterization parameters based on the actual geographical latitude and longitude of the center of each square grid in the two-dimensional grid diagram, the geographical latitude and longitude of the target point, and the observation urgency factor; wherein, the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation urgency factor;

[0160] The characterization unit is used to characterize the observation requirements of the square grid in the two-dimensional grid diagram using the characterization parameters.

[0161] Furthermore, the three-dimensional spatiotemporal grid module 203 includes:

[0162] The visibility submodule is used to determine the satellite's visibility to the square grid in the two-dimensional grid diagram based on the temporal changes of the Earth orbit.

[0163] The grid stacking submodule is used to stack the square grids in the two-dimensional grid diagram after the observation requirements are characterized, according to the time sequence, based on the visibility of the square grids, to obtain a three-dimensional spatiotemporal grid, which is represented as follows:

[0164] ST(x,y,t)=A(x,y,t)κ(x,y)

[0165] in, M represents the number of grid cells in the spatial grid size, K represents the time sequence number of the observation mission endpoint, x,y∈{0,1,2,...,M}, t∈{0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ, where A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the observation urgency factor.

[0166] Furthermore, the path search module 204 includes:

[0167] A function submodule is constructed to pre-obtain the transfer benefits and transfer costs of satellites between observed grid nodes, and to construct an optimization objective function using the transfer benefits and the transfer costs.

[0168] The path search submodule is used to minimize the optimization objective function as the search target, and perform path search on each grid node in a forward expansion manner in the time dimension to obtain the target path observation point set.

[0169] Furthermore, the path search submodule includes:

[0170] A determining unit is used to determine the starting grid and the ending grid, and to determine the grid that minimizes the optimization objective function as the extended grid;

[0171] The search unit is used to traverse and search the extended grid starting from the initial grid in a forward expansion manner along the time dimension, and to obtain the visibility of the extended grid.

[0172] A storage unit is used to store the extended grid into a preset path observation point set if the extended grid is visible and the optimization objective function at the extended grid is minimized.

[0173] The update unit is used to update the preset path observation point set to the target path observation point set when the extended grid is found to overlap with the endpoint grid.

[0174] Furthermore, in the construction function submodule, the optimization objective function is expressed as:

[0175]

[0176] G i,i+1 =βA(x i+1 ,y i+1 )k(x i+1 ,y i+1 )-C i,i+1

[0177] in, Represents the state vector of a grid node. The actual cost from the starting grid node to the current grid node. G is the estimated cost from the current grid node to the target grid node. i，i+1 C represents the transfer reward from the current grid node to the target grid node, β represents the grid task reward factor, and C represents the transfer reward from the current grid node to the target grid node. i，i+1 This represents the transfer cost from the current grid node to the target grid node.

[0178] The satellite Earth observation path planning device provided in this embodiment of the invention acquires the Earth orbit, swath width, and observation task of the satellite to be performed. Based on the Earth orbit and swath width, it divides the expected observation ground area into a two-dimensional grid map containing multiple uniform squares. Then, it characterizes the observation requirements of the two-dimensional grid map according to the observation task. Based on the temporal changes of the Earth orbit, it stacks the two-dimensional grid map after the observation requirements characterization in chronological order to obtain a three-dimensional spatiotemporal grid. Based on the three-dimensional spatiotemporal grid, it searches for path observation points to obtain a set of target path observation points that minimizes a pre-constructed optimization objective function. Finally, it performs path transformation on the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. This invention extends the time dimension into a supplementary dimension of the path planning space, transforming the dynamic satellite-to-ground visibility constraints that change regularly over time into static constraints. This expands two-dimensional path planning into path planning on a three-dimensional spatiotemporal grid, and constructs a path search algorithm suitable for the three-dimensional spatiotemporal grid. This yields the optimal Earth observation path for the satellite to perform its observation mission, achieving efficient processing of time-varying satellite-to-ground visibility constraints, effectively simplifying the processing of dynamic time-varying constraints, and further improving the efficiency of satellite Earth observation path planning.

[0179] Reference Figure 9 The present invention also provides an electronic device, such as... Figure 9 As shown, it includes a processor 301, a communication interface 302, a memory 303, and a communication bus 304, wherein the processor 301, the communication interface 302, and the memory 303 communicate with each other through the communication bus 304.

[0180] Processor 301, memory 303 for storing processor-executable instructions;

[0181] The processor 301 is configured to execute the instructions to implement the satellite Earth observation path planning method described above:

[0182] Obtain the Earth orbit, image swath width, and observation task of the satellite to be performed;

[0183] Based on the Earth orbit and the shooting swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares, and the observation requirements of the two-dimensional grid map are characterized according to the observation task.

[0184] Based on the temporal changes of the Earth orbit, the two-dimensional grid diagrams characterized by the observation requirements are stacked in chronological order to obtain a three-dimensional spatiotemporal grid.

[0185] Based on the three-dimensional spatiotemporal grid, a path observation point search is performed to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function;

[0186] The target path observation point set is transformed to obtain the optimal Earth observation path for the satellite to perform the observation task.

[0187] The communication bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0188] The communication interface is used for communication between the aforementioned terminal and other devices.

[0189] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0190] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0191] In another embodiment of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the satellite Earth observation path planning method described in any of the above embodiments.

[0192] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0193] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0194] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0195] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A satellite Earth observation path planning method, characterized in that, The method includes: The system acquires the Earth orbit, swath width, and observation task of the satellite to be performed; the Earth orbit is the path of the satellite orbiting the Earth, and the Earth orbit includes at least the orbital altitude and orbital inclination. Based on the Earth orbit and the shooting swath width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares, and the observation requirements of the two-dimensional grid map are characterized according to the observation task. Based on the temporal changes of the Earth orbit, the two-dimensional grid diagrams characterized by the observation requirements are stacked in chronological order to obtain a three-dimensional spatiotemporal grid. Based on the three-dimensional spatiotemporal grid, a path observation point search is performed to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function; The target path observation point set is transformed to obtain the optimal Earth observation path for the satellite to perform the observation task. The step of stacking the two-dimensional grid map characterized by the observation requirements according to the temporal changes of the Earth orbit to obtain a three-dimensional spatiotemporal grid includes: Based on the temporal changes in the Earth orbit, the satellite's visibility to the square grid in the two-dimensional grid diagram is determined; Based on the visibility of the square grid, the square grids in the two-dimensional grid diagram after the observation requirements are characterized are stacked in chronological order to obtain a three-dimensional spatiotemporal grid; wherein, the three-dimensional spatiotemporal grid is represented as: ST(x,y,t)=A(x,y,t)κ(x,y) in, M represents the number of grid cells in the spatial grid size, K represents the time sequence number of the observation mission endpoint, x,y∈{0,1,2,...,M}, t∈{0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ, where A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the observation urgency factor.

2. The method according to claim 1, characterized in that, The step of dividing the expected observation ground area into a two-dimensional grid map containing multiple uniform squares based on the Earth orbit and the imaging swath width, and characterizing the observation requirements of the two-dimensional grid map according to the task to be observed, includes: Based on the Earth orbit, determine the maximum observation area of ​​the satellite at each sub-satellite point, and summarize the maximum observation areas of each sub-satellite point to obtain the expected ground observation area; Based on the shooting width, the side length of the square grid to be divided is calculated, and the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares using the side length of the square grid. The characterization parameters are determined based on the task to be observed, and the characterization parameters are used to characterize the observation requirements of the two-dimensional grid diagram.

3. The method according to claim 2, characterized in that, The step of determining the characterization parameters based on the task to be observed, and using the characterization parameters to characterize the observation requirements of the two-dimensional grid map, includes: The geographical latitude and longitude of the target point and the urgency factor of the observation requirement are extracted from the task to be observed. Based on the actual geographical latitude and longitude of the center of each square grid in the two-dimensional grid diagram, the geographical latitude and longitude of the target point, and the observation urgency factor, characterization parameters are generated; wherein, the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation urgency factor; The observation requirements are characterized using the aforementioned characterization parameters on the square grid in the two-dimensional grid diagram.

4. The method according to claim 1, characterized in that, The path observation point search based on the three-dimensional spatiotemporal grid yields a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function, including: The transfer benefits and transfer costs of satellites between observed grid nodes are obtained in advance, and an optimization objective function is constructed using the transfer benefits and the transfer costs; The objective function is minimized as the search objective. Path search is performed on each grid node in a forward expansion manner along the time dimension to obtain the set of observation points for the target path.

5. The method according to claim 4, characterized in that, The optimization objective function is minimized as the search objective. A path search is performed on each grid node using a forward expansion method along the time dimension to obtain a set of target path observation points, including: Determine the starting and ending grids, and define the grid that minimizes the optimization objective function as the expanded grid; Starting from the initial grid, the extended grid is traversed and searched in a forward expansion manner along the time dimension, and the visibility of the extended grid is obtained; If the extended grid is visible and the optimization objective function at the extended grid is minimized, then the extended grid is stored in a preset path observation point set; If the extended grid coincides with the endpoint grid, the preset path observation point set is updated to the target path observation point set.

6. The method according to claim 4, characterized in that, The transfer benefits and costs of satellites between observed grid nodes are obtained in advance. An optimization objective function is constructed using these transfer benefits and costs, and the optimization objective function is expressed as follows: G i,i+1 =βA(x i+1 ,and i+1 )k(x i+1 ,and i+1 )-C i,i+1 in, Represents the state vector of a grid node. The actual cost from the starting grid node to the current grid node. G is the estimated cost from the current grid node to the target grid node. i,i+1 C represents the transfer reward from the current grid node to the target grid node, β represents the grid task reward factor, and C represents the transfer reward from the current grid node to the target grid node. i，i+1 This represents the transfer cost from the current grid node to the target grid node.

7. A satellite Earth observation path planning device, characterized in that, The device includes: The information acquisition module is used to acquire the Earth orbit, swath width, and observation task of the satellite to be performed; the Earth orbit is the path of the satellite orbiting the Earth, and the Earth orbit includes at least the orbital altitude and orbital inclination. The observation requirement characterization module is used to divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares according to the Earth orbit and the shooting swath width, and to characterize the observation requirements of the two-dimensional grid map according to the observation task. The three-dimensional spatiotemporal grid module is used to stack the two-dimensional grid map characterized by the observation requirements in chronological order according to the temporal changes of the orbit around the Earth to obtain a three-dimensional spatiotemporal grid. The path search module is used to search for path observation points based on the three-dimensional spatiotemporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function. The path conversion module is used to convert the target path observation point set to obtain the optimal Earth observation path for the satellite to perform the observation task. The spatiotemporal grid module includes: The visibility submodule is used to determine the satellite's visibility to the square grid in the two-dimensional grid diagram based on the temporal changes of the Earth orbit. The grid stacking submodule is used to stack the square grids in the two-dimensional grid diagram after the observation requirements have been characterized, according to the time sequence, based on the visibility of the square grids, to obtain a three-dimensional spatiotemporal grid; wherein, the three-dimensional spatiotemporal grid is represented as: ST(x,y,t)=A(x,y,t)κ(x,y) in, M represents the number of grid cells in the spatial grid size, K represents the time sequence number of the observation mission endpoint, x,y∈{0,1,2,...,M}, t∈{0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ, where A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the observation urgency factor.

8. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to execute the instructions to implement the satellite Earth observation path planning method as described in any one of claims 1 to 6.

9. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the satellite Earth observation path planning method as described in any one of claims 1 to 6.

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