Satellite earth observation path planning method, device and equipment and storage medium

Abstract

The invention provides a satellite earth observation path planning method and device, equipment and a storage medium, and the method comprises the steps: obtaining the earth-surrounding orbit and shooting breadth of a satellite to be subjected to a task, and a to-be-observed task, dividing a predicted observation ground region into a two-dimensional grid chart containing a plurality of uniform squares, carrying out the observation demand representation of the two-dimensional grid chart, and carrying out the observation demand representation of the two-dimensional grid chart; and according to the time sequence change of the around-the-ground orbit, stacking the two-dimensional grid charts represented by the observation demand according to a time sequence to obtain a three-dimensional space-time grid, searching path observation points based on the three-dimensional space-time grid to obtain a target path observation point set meeting the minimization of a pre-constructed optimization target function, and searching path observation points based on the target path observation point set. And performing path conversion on the target path observation point set to obtain an optimal earth observation path for the satellite to execute the to-be-observed task. According to the method, two-dimensional path planning is expanded into path planning on a three-dimensional space-time grid, the dynamic time-varying constraint processing process is effectively simplified, and the efficiency of satellite earth observation path planning is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite observation, and particularly to a method, device, equipment and storage medium for satellite earth observation path planning. Background Art

[0002] Remote sensing satellites provide a high and comprehensive view for humans to understand the earth and monitor ground events, and play an important role in fields such as agricultural production, resource exploration, map mapping, and disaster relief. With the synchronous growth of the scale of satellite quantity and the scale of ground observation requirements, there are great challenges in satellite mission planning and management. Among them, satellite mission planning refers to using a certain scheduling and planning algorithm to allocate a series of observation tasks to satellites according to an optimal plan to ensure timely meeting of observation requirements and improve the utilization rate of satellite resources.

[0003] At present, satellite earth observation path planning is a key issue in satellite mission planning. Specifically, it uses a path planning algorithm to solve the observation point positions and time trajectories during the process of satellites performing a series of observation tasks. The existing technology conducts path planning on a two-dimensional space grid map of satellite earth observation. Due to the dynamic nature of observation task 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-ground visibility and changes in observation requirements. Temporary calculation and judgment of satellite-ground visibility at new grid positions are required every time the grid is expanded, resulting in a large amount of unnecessary computing power consumption and time consumption, further affecting the efficiency of satellite earth observation path planning. Summary of the Invention

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

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

[0006] Obtaining the earth orbit, shooting width of the satellite to be executed with tasks, and the tasks to be observed;

[0007] According to the earth orbit and the shooting width, dividing the predicted ground observation area into a two-dimensional grid map containing a plurality of uniform squares, and characterizing the observation requirements for the two-dimensional grid map according to the tasks to be observed;

[0008] According to the time sequence change of the earth orbit, stacking the two-dimensional grid map after characterizing the observation requirements in chronological order to obtain a three-dimensional space-time grid;

[0009] Search for path observation points based on the three-dimensional spatio-temporal grid to obtain a set of target path observation points that minimize a pre-constructed optimization objective function;

[0010] Perform path conversion on the set of target path observation points to obtain the optimal ground observation path for the satellite to perform the to-be-observed task.

[0011] Optionally, dividing the expected observation ground area into a two-dimensional grid map containing multiple uniform squares according to the orbiting path and the shooting width, and characterizing the observation requirements for the two-dimensional grid map according to the to-be-observed task, includes:

[0012] Determine the maximum observation area of the satellite to be tasked at each sub-satellite point according to the orbiting path, and summarize the maximum observation areas of each sub-satellite point to obtain the expected observation ground area;

[0013] Calculate the side length of the square grid to be divided according to the shooting width, and divide the expected observation ground area into a two-dimensional grid map containing multiple uniform squares using the side length of the square grid;

[0014] Determine the characterization parameters according to the to-be-observed task, and use the characterization parameters to characterize the observation requirements for the two-dimensional grid map.

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

[0016] Extract the geographical longitude and latitude of the target point and the urgency factor of the observation requirement in the to-be-observed task;

[0017] Generate characterization parameters according to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement; wherein, the characterization parameters include the position coordinates of the square grid in the two-dimensional plane and the urgency factor of the observation requirement;

[0018] Use the characterization parameters to characterize the observation requirements for the square grids in the two-dimensional grid map.

[0019] Optionally, stacking the two-dimensional grid map with characterized observation requirements in chronological order according to the temporal variation of the orbiting path to obtain a three-dimensional spatio-temporal grid, includes:

[0020] Determine the visibility of the satellite to the square grids in the two-dimensional grid map according to the temporal variation of the orbiting path;

[0021] Based on the visibility of the square grid, stack the square grids in the two-dimensional grid map after characterizing the observation requirements in chronological order to obtain a three-dimensional spatio-temporal grid, and the three-dimensional spatio-temporal grid is expressed as:

[0022] ST(x,y,t) = A(x,y,t)κ(x,y)

[0023] Where, M represents the number of grids of the spatial grid size, K represents the serial number of the moment at the end of the observation task, 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 factor of the urgency degree of the observation requirement.

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

[0025] Pre-obtain the transfer benefit and transfer cost of the satellite between the observed grid nodes, and construct an optimization objective function using the transfer benefit and the transfer cost;

[0026] Determine the minimization of 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 a set of target path observation points.

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

[0028] Determine the starting grid and the ending grid, and determine the grid that minimizes the optimization objective function as the expanding grid;

[0029] Start from the starting grid, perform a traversal search on the expanding grid in a forward expansion manner in the time dimension, and obtain the visibility of the expanding grid;

[0030] If the expanding grid is visible and the optimization objective function at the expanding grid is minimized, then store the expanding grid in a preset set of path observation points;

[0031] In the case where it is searched that the expanding grid coincides with the ending grid, update the preset set of path observation points to the set of target path observation points.

[0032] Optionally, 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 the 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] Wherein, represents the state vector of the grid node, is the actual cost from the starting grid node to the current grid node, is the estimated cost from the current grid node to the target grid node, G i，i+1 represents the transfer benefit from the current grid node to the target grid node, β represents the grid task benefit factor, G i，i+1 represents the transfer cost from the current grid node to the target grid node.

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

[0037] An information acquisition module, configured to acquire the orbiting orbit, shooting width, and observation task to be performed of the satellite;

[0038] An observation requirement characterization module, configured to divide the predicted observed ground area into a two-dimensional grid map containing a plurality of uniform squares according to the orbiting orbit and the shooting width, and characterize the observation requirements for the two-dimensional grid map according to the observation task to be performed;

[0039] A three-dimensional space-time grid module, configured to stack the two-dimensional grid map after the observation requirements are characterized in chronological order according to the chronological changes of the orbiting orbit to obtain a three-dimensional space-time grid;

[0040] A path search module, configured to search for path observation points based on the three-dimensional space-time grid to obtain a set of target path observation points that satisfy the minimization of the pre-constructed optimization objective function;

[0041] A path conversion module, configured to perform path conversion on the set of target path observation points to obtain an optimal earth observation path for the satellite to perform the observation task to be performed.

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

[0043] A processor;

[0044] A memory for storing the processor-executable instructions;

[0045] Wherein, the processor is configured to execute the instructions to implement the satellite-to-ground observation path planning method as described above.

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

[0047] The satellite-to-ground observation path planning method provided by the embodiments of the present invention obtains the orbiting orbit, shooting width and observation tasks of the satellite to be executed, divides the expected observation ground area into a two-dimensional grid map containing multiple uniform squares according to the orbiting orbit and shooting width, and, according to the observation tasks, characterizes the observation requirements of the two-dimensional grid map, stacks the two-dimensional grid map with characterized observation requirements in chronological order according to the chronological changes of the orbiting orbit to obtain a three-dimensional spatio-temporal grid, searches for path observation points based on the three-dimensional spatio-temporal grid to obtain a set of target path observation points that minimize the pre-constructed optimization objective function, and performs path conversion on the set of target path observation points to obtain the optimal satellite-to-ground observation path for the satellite to execute the observation tasks. The embodiments of the present invention expand the time dimension into an additional dimension of the path planning space, transform the dynamic satellite-ground visibility constraint that changes regularly with time into a static constraint, realize the expansion of two-dimensional path planning into path planning on a three-dimensional spatio-temporal grid, and construct a path search algorithm applicable to the three-dimensional spatio-temporal grid, thereby obtaining the optimal satellite-to-ground observation path when the satellite realizes the observation tasks, realizing the efficient processing of time-varying satellite-ground visibility constraints, effectively simplifying the processing process of dynamic time-varying constraints, and further improving the efficiency of satellite-to-ground observation path planning.

[0048] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other objects, features and advantages of the present invention more obvious and understandable, the following specifically illustrates the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0050] Figure 1It is a flowchart of the steps of a satellite earth observation path planning method provided by an embodiment of the present invention;

[0051] Figure 2 It is Figure 1 a flowchart of step 102 in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0052] Figure 3 It is Figure 1 a flowchart of step 103 in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0053] Figure 4 It is Figure 1 a flowchart of step 104 in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0054] Figure 5 It is a schematic diagram of a square grid of a satellite in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0055] Figure 6 It is a schematic diagram of representing observation requirements in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0056] Figure 7 It is a schematic diagram of the transfer cost of an observation task in the satellite earth observation path planning method provided by an embodiment of the present invention;

[0057] Figure 8 It is a schematic diagram of the structure of a satellite earth observation path planning device provided by an embodiment of the present invention;

[0058] Figure 9 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Specific embodiments

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will elaborate on the various embodiments of the present invention with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the various embodiments of the present invention, many technical details are presented to help the reader better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented. The following division of the various embodiments is for convenience of description and should not constitute any limitation to the specific implementation of the present invention. The various embodiments can be combined and cross-referenced with each other without conflict.

[0060] Referring to Figure 1 , a flowchart of the steps of a satellite earth observation path planning method provided by an embodiment of the present invention is shown, and the method may include:

[0061] Step 101: Obtain the earth orbit, shooting width, and observation task of the satellite to be executed.

[0062] In the embodiment of the present invention, for the requirement of satellite earth observation path planning, to solve the problem that the satellite earth observation path planning is strongly restricted by time-varying factors such as satellite-earth visibility and changing observation requirements, and it is necessary to temporarily calculate and judge the satellite-earth visibility of the new grid position during each grid expansion, resulting in a large amount of unnecessary computing power consumption and time consumption, further affecting the efficiency of satellite earth observation path planning. In this embodiment, the time dimension is extended to an additional dimension of the path planning space, and the two-dimensional space path planning is extended to path planning on a three-dimensional space-time grid. Furthermore, the satellite-earth visibility constraint that changes with time is transformed into a static constraint, and satellite earth observation path planning is realized based on the three-dimensional space-time grid, effectively simplifying the processing 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 along which the satellite orbits the earth. The earth orbit includes parameters such as orbital altitude and orbital inclination, and its parameters directly affect the satellite's observation ability and coverage. The earth orbit determines the satellite's sub-satellite point trajectory and coverage. The shooting width is the ground width that the satellite sensor can cover in a single shot. The observation task is the specific target executed by the satellite. The observation task includes observation requirements and task priorities. Among them, the task priority is represented by the urgency factor of the observation requirements at each target location in a certain observation task.

[0064] Step 102: Divide the predicted ground observation area into a two-dimensional grid map containing multiple uniform squares according to the earth orbit and shooting width, and characterize the observation requirements for the two-dimensional grid map according to the observation task.

[0065] In the embodiment of the present invention, according to the earth orbit and shooting width, the predicted ground observation area is divided into a two-dimensional grid map containing multiple uniform squares. Specifically, based on the earth orbit of the satellite to be executed, that is, the movement path of the satellite, the maximum observation area of the satellite at each sub-satellite point can be determined on the movement path of the satellite. The integration of the maximum observation areas of each sub-satellite point can obtain all the areas that the satellite can observe during its flight around the earth, that is, the predicted ground observation area. Among them, the sub-satellite point of the satellite 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, usually represented by longitude and latitude coordinates. The sub-satellite point trajectory is the path formed on the earth's surface when the satellite orbits the earth.

[0066] In this embodiment, according to the shooting width of the satellite, the predicted ground observation area is divided into a two-dimensional grid map including a plurality of uniform square grids of the same size, where each square grid can be exactly and completely covered by a satellite payload in one shot. Refer to Figure 5 , which shows a schematic diagram of the square grid of the satellite in the satellite ground observation path planning method provided by the embodiment of the present invention. Among them, the side length of each square grid in the two-dimensional grid map is the side length of the inscribed square of a circle with a diameter length equal to the shooting width.

[0067] It should be noted that the satellite payload is a device or instrument carried on the satellite for performing specific tasks, and it is the core component of the satellite, directly determining the functions and uses of the satellite. In this embodiment, according to the task requirements, the satellite payload can be an optical camera, a radar, a communication device, a scientific instrument, etc., which are not specifically limited here.

[0068] Specifically, the observation requirement characterization refers to the process of uniformly characterizing the observation requirements from multiple industries and directions onto the grid map. The urgency factor of the observation requirement for a certain to-be-observed task is predefined. The larger the value of the urgency factor of the observation requirement, the more urgent the need for the corresponding to-be-observed task to be observed, that is, the higher the task priority. In this embodiment, the observation requirement characterization of the two-dimensional grid map according to the to-be-observed task is specifically achieved by extracting the geographical longitude and latitude of the target point and the urgency factor of the observation requirement in the to-be-observed task. The geographical longitude and latitude of the target point are the end positions of the to-be-observed task. According to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement, a characterization parameter is generated. The characterization parameter includes the position coordinates of the square grid in the two-dimensional plane and the urgency factor of the observation requirement. Thus, the square grids in the two-dimensional grid map are characterized by using the characterization parameter.

[0069] Step 103: Stack the two-dimensional grid map after observation requirement characterization in chronological order according to the timing change of the earth orbit to obtain a three-dimensional spatio-temporal grid.

[0070] In the embodiment of the present invention, the three-dimensional spatio-temporal grid is a three-dimensional data structure formed by adding a time dimension on the basis of the two-dimensional space grid. Its three dimensions are: the spatial dimension (longitude, latitude), which is used to represent the position of the ground area; the time dimension, which is used to represent the observation opportunities of the satellite at different time points. Therefore, according to the timing change of the earth orbit, stacking the two-dimensional grid map after observation requirement characterization can obtain a three-dimensional spatio-temporal grid. Each grid contains observation requirement characterization, and the characterization parameter includes the position coordinates of the square grid in the two-dimensional plane and the urgency factor of the observation requirement, so as to effectively combine space and time information after expanding the two-dimensional grid map into a three-dimensional spatio-temporal grid.

[0071] Specifically, when expanding the spatio-temporal grid in the spatio-temporal dimension for the square grid characterized by the observation requirements, considering the orbital motion of the satellite and the limited payload sensing range, only part of the grid is visible at a certain moment. Whether the observation target has the opportunity to be observed is restricted by the space-ground visibility that changes with time. The space-ground visibility is time-varying but predictable. Therefore, in this embodiment, a binary variable is used to represent the visibility of the satellite to the square grid at a certain moment. When the satellite is invisible to the square grid, the binary variable of the visibility takes a value of 0. When the satellite is visible to the square grid, the binary variable of the visibility takes a value of 1. After determining the visible square grids, the square grids are stacked in chronological order to obtain a three-dimensional spatio-temporal grid.

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

[0073] In the embodiment of the present invention, considering the transfer cost of the satellite in the observation task and the benefit of the observation task, there is an optimal path during the payload maneuvering process. The transfer benefit and transfer cost between the observed grid nodes of the satellite are obtained in advance, and an optimization objective function is constructed using the transfer benefit and transfer cost. Path observation points are searched based on the three-dimensional spatio-temporal grid, and the path observation points that minimize the optimization objective function are searched to obtain a set of target path observation points that minimize the pre-constructed optimization objective function.

[0074] In this embodiment, for the problem of task grid observation sequence planning, an ST-A* algorithm is constructed, that is, an optimization algorithm obtained by expanding the A* algorithm to the three-dimensional spatio-temporal space. Considering the requirement of path planning on the three-dimensional spatio-temporal grid, the A* algorithm is expanded to the three-dimensional spatio-temporal space to construct a spatio-temporal A* algorithm, simply referred to as the ST-A* algorithm. The ST-A* algorithm is essentially a heuristic search algorithm, and the search nodes are expanded with the goal of minimizing the optimization objective function, so as to obtain a set of target path observation points that minimize the pre-constructed optimization objective function.

[0075] Step 105: Perform path conversion on the set of target path observation points to obtain the optimal ground observation path for the satellite to perform the to-be-observed task.

[0076] In the embodiment of the present invention, through the search for path observation points, a set of target path observation points that minimize the optimization objective function can be obtained. The observation points in the set of target path observation points are arranged in chronological order. The best sequence of grids that the satellite needs to photograph in sequence from time 0 to time K is the set of observation points of the optimal ground observation path, denoted as where each observation point is the coordinate of a certain square grid in the corresponding three-dimensional spatio-temporal grid.

[0077] Specifically, perform path conversion on the set of target path observation points to obtain the optimal ground observation path for the satellite to perform the to-be-observed task. When sequentially performing grid shooting tasks, the longitude and latitude trajectory of the satellite observation point is determined by the square grid coordinates (x, y), and the execution time of the satellite observation point is consistent with the grid time coordinate t. Denote the actual time at time t as T t , and denote the longitude and latitude of the satellite observation point at time t as Then, the spatio-temporal trajectory of the satellite observation point, i.e., the optimal ground observation path, can be obtained by converting each element according to the following formula:

[0078]

[0079] The satellite ground observation path planning method provided by the embodiments of the present invention obtains the orbiting orbit, shooting width, and to-be-observed task of the satellite to be executed. According to the orbiting orbit and shooting width, the predicted observation ground area is divided into a two-dimensional grid map containing multiple uniform squares. Further, according to the to-be-observed task, the two-dimensional grid map is characterized by observation requirements. According to the time sequence change of the orbiting orbit, the two-dimensional grid map characterized by observation requirements is stacked in chronological order to obtain a three-dimensional spatio-temporal grid. Based on the three-dimensional spatio-temporal grid, path observation points are searched to obtain a set of target path observation points that satisfy the minimization of the pre-constructed optimization objective function. Perform path conversion on the set of target path observation points to obtain the optimal ground observation path for the satellite to perform the to-be-observed task. The embodiments of the present invention expand the time dimension into an additional dimension of the path planning space, convert the dynamic satellite-ground visibility constraint that changes regularly with time into a static constraint, realize the expansion of two-dimensional path planning to path planning on a three-dimensional spatio-temporal grid, and construct a path search algorithm applicable to the three-dimensional spatio-temporal grid, thereby obtaining the optimal ground observation path of the satellite when performing the to-be-observed task, realizing the efficient processing of time-varying satellite-ground visibility constraints, effectively simplifying the processing process of dynamic time-varying constraints, and further improving the efficiency of satellite ground observation path planning.

[0080] Further, referring to Figure 2 , shows Figure 1 The flowchart of step 102 in a satellite ground observation path planning method provided, which is basically the same as the satellite ground observation path planning method provided by the first embodiment of the present invention. Step 102 may include:

[0081] Step 1021, determine the maximum observation area of the satellite to be executed at each sub-satellite point according to the orbiting orbit, and summarize the maximum observation areas of each sub-satellite point to obtain the predicted observation ground area.

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

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

[0084] In the embodiment of the present invention, referring to Figure 6 , it shows a schematic diagram of the observation requirement characterization in the satellite ground observation path planning method provided by the embodiment of the present invention. Based on the satellite flight direction, determine the maximum observation area of the satellite to be tasked at each sub-satellite point. Specifically, according to the satellite's orbital parameters around the earth, such as orbital altitude, orbital type, and sensor field of view angle, obtain the maximum ground coverage width of the satellite's single observation, that is, the maximum observation area of the satellite at each sub-satellite point. For each sub-satellite point, determine its maximum observation area as a circular area, and superimpose the maximum observation areas of each sub-satellite point to obtain the ground area that the satellite is expected to cover within a preset time period, that is, the predicted ground observation area.

[0085] Specifically, based on the predicted ground observation area, first divide to obtain a two-dimensional grid map. It is necessary to calculate the side length of the square grid to be divided according to the shooting width, and divide the predicted ground observation area into a two-dimensional grid map containing multiple uniform squares using the side length of the square grid. The side length of each square grid in the two-dimensional grid map is the side length of the inscribed square of a circle with a diameter length equal to the shooting width. The calculation method of the side length of the square grid is as follows:

[0086]

[0087] Among them, d represents the shooting width of the satellite, and l represents the side length of the square grid.

[0088] In this embodiment, determine the characterization parameters according to the task to be observed, and use the characterization parameters to characterize the observation requirements of the two-dimensional grid map. First, extract the geographical longitude and latitude of the target point and the urgency factor of the observation requirement in the task to be observed. According to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement, generate the characterization parameters. Among them, the characterization parameters include the position coordinates of the square grid in the two-dimensional plane and the urgency factor of the observation requirement, so as to use the characterization parameters to characterize the observation requirements of the square grids in the two-dimensional grid map.

[0089] In the embodiment of the present invention, by dividing the predicted ground observation area into a two-dimensional grid map and characterizing the observation requirements, it is convenient to expand from the two-dimensional grid map to a three-dimensional spatio-temporal grid map based on the square grids after the observation requirement characterization, and realize the expansion of the two-dimensional path planning to the path planning on the three-dimensional spatio-temporal grid.

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

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

[0092] Sub-step 02: Generate characterization parameters according to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement; among them, the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the urgency factor of the observation requirement;

[0093] Sub-step 03: Use the characterization parameters to characterize the observation requirements of the square grids in the two-dimensional grid map.

[0094] It should be noted that in the above steps, when characterizing the observation requirements of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point and the corresponding urgency factor of the observation requirement are extracted in the task to be observed. The geographical longitude and latitude of the target point are used to represent the specific position of the observation end point of the observation task. According to the actual geographical longitude and latitude of the center of each square grid, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement, the characterization parameters are generated, and the corresponding square grid is characterized according to the characterization parameters.

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

[0096]

[0097] Among them, δ represents the actual surface distance corresponding to a unit of longitude and latitude, and its value is 111.32 km / °, represents the actual geographical longitude and latitude corresponding to the grid center on the square grid, represents the geographical longitude and latitude 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 requirement characterization parameters of each square grid, and use the characterization parameters as the parameters representing the position coordinates of the square grid on the two-dimensional plane, and combine the urgency factor of the observation requirement to characterize the observation requirements of the corresponding square grid.

[0099] In the embodiments of the present invention, by determining the position coordinate parameters of the two-dimensional grid map and the factor of urgency of the observation requirements, the observation requirements of the square grid are accurately characterized, thereby improving the accuracy of expanding the three-dimensional spatio-temporal grid.

[0100] Further, referring to Figure 3 , a flowchart of step 103 in a satellite earth observation path planning method provided is shown. 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: Figure 1

[0101] Step 1031, determine the visibility of the satellite to the square grid in the two-dimensional grid map according to the temporal variation of the earth-orbiting trajectory.

[0102] Step 1032, based on the visibility of the square grid, stack the square grids in the two-dimensional grid map after characterizing the observation requirements in chronological order to obtain a three-dimensional spatio-temporal grid.

[0103] Among them, the three-dimensional spatio-temporal grid is expressed as:

[0104] ST(x,y,t) = A(x,y,t)κ(x,y)

[0105] Among them, M represents the number of grids of the spatial grid size, K represents the moment serial number of the end of the observation task, x,y ∈ {0,1,2,...,M}, t ∈ {0,1,2,...,K}, and the element at (x,y,t) in ST is Aκ. Among them, A represents the visibility of the satellite to the square grid (x,y) at time t, and κ represents the factor of urgency of the observation requirements.

[0106] It should be noted that in the embodiments of the present invention, when expanding the spatio-temporal grid in the spatio-temporal dimension based on the two-dimensional grid map after characterizing the observation requirements, considering the orbital motion of the satellite and the limited load perception range, only part of the grids are visible at a certain moment, that is, restricted by the space-earth visibility that changes with time. The visible area on the ground at a certain moment will change with the passage of time and the orbital motion of the satellite. Since the space-earth visibility is time-varying but predictable, in this embodiment, the binary variable A is used to represent the visibility of the satellite to the square grid (x,y) at a certain moment. When the satellite is invisible to the square grid (x,y), A takes the value of 0. When the satellite is visible to the square grid (x,y), A takes the value of 1. Then, stack each square grid in chronological order of time t to obtain a three-dimensional spatio-temporal grid, whose horizontal and vertical coordinates are x,y,t respectively, and the brightness value of each grid is A(x,y,t)κ(x,y). In this embodiment, a three-dimensional matrix will be constructed. Store a three-dimensional spatio-temporal grid, where M represents the number of grids of the spatial grid size, and K represents the serial number of the moment at the end of the observation task. Since the visibility between the grid and the satellite is predictable, the three-dimensional spatio-temporal grid can be pre-constructed before the satellite observation path planning. Assume that the total time length of the satellite platform and payload attitude adjustment, attitude stabilization, and observation imaging during each observation task executed by the satellite is fixed, denoted as Δt. The unit length of the spatio-temporal grid in the t dimension is taken as Δt, and the unit length in the x and y dimensions is l.

[0107] In the embodiment of the present invention, by expanding the time dimension into an additional dimension of the path planning space, the dynamic satellite-ground visibility constraint that changes regularly with time is transformed into a static constraint, so as to realize the expansion of the two-dimensional path planning into the path planning on the three-dimensional spatio-temporal grid.

[0108] Further, referring to Figure 4 shows Figure 1 The flowchart of step 104 in a satellite earth observation path planning method provided, which is basically the same as the satellite earth observation path planning method provided by the first embodiment of the present invention. Step 104 may include:

[0109] Step 1041, pre-obtain the transfer benefit and transfer cost between the observed grid nodes of the satellite, and construct an optimization objective function by using the transfer benefit and transfer cost;

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

[0111] It should be noted that in the embodiment of the present invention, when pre-obtaining the transfer benefit and transfer cost between the observed grid nodes of the satellite and constructing an optimization objective function by using the transfer benefit and transfer cost, an objective function needs to be constructed when searching for the optimal earth observation path based on the three-dimensional spatio-temporal grid. In this embodiment, the objective function is constructed according to the transfer benefit and transfer cost of the satellite observation point migrating from one grid node to another grid node.

[0112] Specifically, first consider the observation task transfer cost. Assume that the satellite payload observes the area (x1, y1) at time t1 and observes the grid (x2, y2) at time t2. From t1 to t2, the observation point of the satellite payload moves from (x1, y1) to (x2, y2). Considering the limitations of factors such as energy consumption and component loss, there is an optimal path during the payload maneuvering process. At the same time, the satellite orbital motion will bring certain benefits to the maneuvering cost of its observation task switching. Considering the benefits of the observation task, the benefit obtained when each grid is observed is related to the urgency of the observation demand for that grid. 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] Among them, represents the node state vector, is the cost function, which is used to represent the actual cost from the starting node to the current node . is the heuristic function, which is used to represent the estimated cost from the current node to the target node .

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

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

[0117] Sub-step 01, determine the starting grid and the ending grid, and determine the grid with the minimum optimization objective function as the expanding grid;

[0118] Sub-step 02, starting from the starting grid, perform a traversal search on the expanding grid in the forward expansion manner in the time dimension, and obtain the visibility of the expanding grid;

[0119] Sub-step 03, if the expanding grid is visible and the optimization objective function at the expanding grid is minimized, store the expanding grid into the preset path observation point set;

[0120] Sub-step 04, in the case where the expanding grid coincides with the ending grid, update the preset path observation point set to the target path observation point set.

[0121] It should be noted that in the embodiments of the present invention, minimizing the optimization objective function is determined as the search target, and path search is performed on each grid node in the forward expansion manner in the time dimension to obtain a set of target path observation points. The ST-A* algorithm is constructed by extending the A* algorithm to the three-dimensional spatio-temporal space. Considering the need for path planning on a three-dimensional spatio-temporal grid, the A* algorithm is extended to the three-dimensional spatio-temporal space to construct a spatio-temporal A* algorithm, simply referred to as the ST-A* algorithm. The ST-A* algorithm is essentially a heuristic search algorithm, and the search node expansion is carried out with the goal of minimizing the objective evaluation function.

[0122] Specifically, when using the ST-A* algorithm to perform path search in the three-dimensional spatio-temporal grid ST, the node state vector is (x, y, t), represents the starting grid, and there is represents the end grid, that is From extended to When expanding, the nodes expand with a step size of l in two spatial dimensions, that is, on a two-dimensional plane. At a certain node, it can move to 9 grid positions adjacent to the current node in the distance dimension (including staying still). Therefore, there is:

[0123]

[0124] In the time dimension, the grid nodes expand with a step size of Δt, but can only grow strictly in the forward direction of time. That is, in the time dimension, t can only be expanded by "+1" and cannot remain unchanged or decrease. Therefore, starting from the starting grid, the expanded grid is traversed and searched in the 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. When it is searched that the expanded grid coincides with the end grid, the preset path observation point set is updated to the target path observation point set.

[0125] Exemplarily, 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 been explored respectively. The specific algorithm flow is as follows:

[0126] S1, Algorithm initialization: Calculate And place the starting node in OpenSet.

[0127] S2, Select in OpenSet The node with the minimum As the current expansion node, and transfer it to the CloseSet collection.

[0128] S3. Traverse and search any new nodes around it in the direction of increasing t dimension, where t = t + 1, and make judgments and executions according to the following rules: new If A(x

[0129] , y new , y new ) = 0, it indicates that is invisible, then is an unreachable node, and abandon this node; otherwise, is a reachable node, and make the following judgment: If is not included in the OpenSet collection, then calculate 's optimized objective function value, and add to the OpenSet collection, with as 's parent node; if already exists in the OpenSet collection, denote the existing node as and judge and 's size. If the function value of the new reachable node is greater than or equal to the function value of the existing node in the collection, then abandon this node; otherwise, replace with and use as 's parent node.

[0130] S4. If the OpenSet is an empty set, return no feasible solution and end the algorithm; if the OpenSet is non-empty, make judgments and executions according to the following rules: If then the optimal path has been found. Trace the parent nodes in sequence starting from and arrange them in reverse order to obtain the optimal path; if then continue to repeat steps 2 - 3.

[0131] Specifically, step 1041 pre-obtains the transfer benefits and transfer costs between the satellite at the observed grid nodes, constructs an optimized objective function using the transfer benefits and transfer costs, and the optimized 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] Among them, represents the state vector of the grid node, is the actual cost from the starting grid node to the current grid node, is the estimated cost from the current grid node to the target grid node, G i，i+1 represents the transfer benefit from the current grid node to the target grid node, and β represents the grid task benefit factor, G i，i+1 represents the transfer cost from the current grid node to the target grid node.

[0135] In the embodiment of the present invention, from to the sub-path constructs the cost function and the heuristic function respectively as:

[0136]

[0137] It is easy to prove that and meet the optimal conditions of the A* algorithm:

[0138]

[0139] Among them, is the actual optimal objective evaluation function from the current node to the end task grid .

[0140] In this embodiment, referring to Figure 7 , a schematic diagram of the observation task transfer cost in the satellite ground observation path planning method provided by the embodiment of the present invention is shown. The transfer cost is characterized by the straight-line distance between two observation points, denoted as Among them, It is easy to know that the satellite orbital motion will bring certain benefits to the maneuvering cost of its observation task switching. Assume that the direction vector of the projection of the satellite sub-satellite point trajectory in the grid coordinate system is satisfies The maneuvering distance benefit can be expressed as the vector product of and

[0141]

[0142] Among them, α represents the orbital motion benefit factor, which is used to adjust the proportion of the impact of orbital motion on cost, and α < 0.

[0143] Considering the benefit of the observation task, the benefit obtained when each grid completes the observation is related to the urgency of the observation requirement of the grid. The task benefit of the observation grid can be calculated as βAκ. β is the grid task benefit factor, where β > 0, which is used to adjust the proportion of the grid task benefit in the comprehensive benefit function. Considering the task transfer cost and the grid task benefit, the transfer benefit from (x1, y1) to (x2, y2) is constructed and denoted as G 1,2 , then there is:

[0144] G 1,2 = βA(x2, y2)κ(x2, y2) - C 1,2

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

[0146] Based on the extended three-dimensional spatio-temporal grid, the embodiment of the present invention constructs a path search algorithm applicable to the three-dimensional spatio-temporal grid, so as to obtain the optimal ground observation path when the satellite realizes the to-be-observed task, and realizes the efficient processing of the time-varying satellite-ground visibility constraint.

[0147] Referring to Figure 8 , a schematic structural diagram of a satellite ground observation path planning device 200 provided by an embodiment of the present invention is shown. The device includes:

[0148] An information acquisition module 201, configured to acquire the earth orbit, shooting width, and to-be-observed task of the satellite to be executed;

[0149] An observation requirement characterization module 202, configured to divide the predicted ground observation area into a two-dimensional grid map containing a plurality of uniform squares according to the earth orbit and the shooting width, and characterize the observation requirements for the two-dimensional grid map according to the to-be-observed task;

[0150] A three-dimensional spatio-temporal grid module 203, configured to stack the two-dimensional grid map after the observation requirement is characterized in chronological order according to the chronological change of the earth orbit to obtain a three-dimensional spatio-temporal grid;

[0151] A path search module 204, configured to search for path observation points based on the three-dimensional spatio-temporal grid to obtain a set of target path observation points that satisfy the minimization of a pre-constructed optimization objective function;

[0152] A path conversion module 205 for performing path conversion on the set of target path observation points to obtain an optimal ground observation path for the satellite to perform the to-be-observed task.

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

[0154] A region sub-module for determining the maximum observation region of the satellite to perform the task at each sub-satellite point according to the earth orbit, and summarizing the maximum observation regions of each sub-satellite point to obtain a predicted observed ground region;

[0155] A division sub-module for calculating the side length of the square grid to be divided according to the shooting width, and dividing the predicted observed ground region into a two-dimensional grid map containing a plurality of uniform squares by using the side length of the square grid;

[0156] A characterization sub-module for determining a characterization parameter according to the to-be-observed task, and performing observation requirement characterization on the two-dimensional grid map by using the characterization parameter.

[0157] Furthermore, the characterization sub-module includes:

[0158] An extraction unit for extracting the geographical longitude and latitude of the target point and the urgency factor of the observation requirement in the to-be-observed task;

[0159] A generation unit for generating a characterization parameter according to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the urgency factor of the observation requirement; wherein the characterization parameter includes the position coordinates of the square grid in the two-dimensional plane and the urgency factor of the observation requirement;

[0160] A characterization unit for performing observation requirement characterization on the square grid in the two-dimensional grid map by using the characterization parameter.

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

[0162] A visibility sub-module for determining the visibility of the satellite to the square grid in the two-dimensional grid map according to the temporal variation of the earth orbit;

[0163] A grid stacking sub-module for stacking the square grids in the two-dimensional grid map after observation requirement characterization in time sequence based on the visibility of the square grid to obtain a three-dimensional spatio-temporal grid, and the three-dimensional spatio-temporal grid is expressed as:

[0164] ST(x,y,t) = A(x,y,t)κ(x,y)

[0165] Wherein, Let \(M\) denote the number of grids for the spatial grid size, \(K\) denote the sequence number of the time point at the end of the observation task, \(x,y\in\{0,1,2,\cdots,M\}\), \(t\in\{0,1,2,\cdots,K\}\), and the element at \((x,y,t)\) in \(ST\) be \(A_{\kappa}\), where \(A\) represents the visibility of the satellite to the square grid \((x,y)\) at time \(t\), and \(\kappa\) represents the factor of the urgency degree of the observation requirement.

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

[0167] A construction function sub-module, configured to pre-obtain the transfer benefit and transfer cost between the observed grid nodes of the satellite, and construct an optimization objective function by using the transfer benefit and the transfer cost;

[0168] A path search sub-module, configured to determine minimizing 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 a set of target path observation points.

[0169] Further, the path search sub-module includes:

[0170] A determination unit, configured to determine the starting grid and the ending grid, and determine the grid that minimizes the optimization objective function as the expanding grid;

[0171] A search unit, configured to start from the starting grid, perform a traversal search on the expanding grid in a forward expansion manner in the time dimension, and obtain the visibility of the expanding grid;

[0172] A storage unit, configured to store the expanding grid into a preset path observation point set if the expanding grid is visible and the optimization objective function at the expanding grid is minimized;

[0173] An update unit, configured to update the preset path observation point set to a set of target path observation points when it is searched that the expanding grid coincides with the ending grid.

[0174] Further, for the construction function sub-module, the optimization objective function is expressed as:

[0175]

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

[0177] Where represents the state vector of the grid node, is the actual cost from the starting grid node to the current grid node, is the estimated cost from the current grid node to the target grid node, G i，i+1 represents the transfer benefit from the current grid node to the target grid node, β represents the grid task benefit factor, C i，i+1 represents the transfer cost from the current grid node to the target grid node.

[0178] The satellite ground observation path planning device provided by the embodiments of the present invention obtains the orbiting orbit, shooting width, and observation task of the satellite to be executed. According to the orbiting orbit and shooting width, the expected observation ground area is divided into a two-dimensional grid map containing multiple uniform squares. Moreover, according to the observation task, the two-dimensional grid map is characterized by observation requirements. According to the time sequence change of the orbiting orbit, the two-dimensional grid map characterized by observation requirements is stacked in chronological order to obtain a three-dimensional spatio-temporal grid. Based on the three-dimensional spatio-temporal grid, path observation points are searched to obtain a set of target path observation points that minimize the pre-constructed optimization objective function. The target path observation point set is converted to obtain the optimal ground observation path for the satellite to execute the observation task. The embodiments of the present invention expand the time dimension into an additional dimension of the path planning space, convert the dynamic satellite-ground visibility constraint that changes regularly with time into a static constraint, realize the expansion of two-dimensional path planning to path planning on a three-dimensional spatio-temporal grid, and construct a path search algorithm applicable to the three-dimensional spatio-temporal grid, thereby obtaining the optimal ground observation path for the satellite to realize the observation task, realizing the efficient processing of the time-varying satellite-ground visibility constraint, effectively simplifying the processing process of dynamic time-varying constraints, and further improving the efficiency of satellite ground observation path planning.

[0179] Referring to Figure 9 , the embodiments of the present invention also provide an electronic device, as Figure 9 shown, including a processor 301, a communication interface 302, a memory 303, and a communication bus 304. Among them, the processor 301, the communication interface 302, and the memory 303 communicate with each other through the communication bus 304,

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

[0181] wherein, the processor 301 is configured to execute the instructions to implement the satellite ground observation path planning method as described above:

[0182] Obtain the orbiting orbit, shooting width, and observation task of the satellite to be executed;

[0183] According to the earth-orbiting trajectory and the shooting width, the predicted ground observation area is divided into a two-dimensional grid map containing a plurality of uniform squares, and, according to the task to be observed, the two-dimensional grid map is characterized by observation requirements;

[0184] According to the temporal variation of the earth-orbiting trajectory, the two-dimensional grid map characterized by observation requirements is stacked in chronological order to obtain a three-dimensional spatio-temporal grid;

[0185] Based on the three-dimensional spatio-temporal grid, a search for path observation points is performed to obtain a set of target path observation points that minimizes a pre-constructed optimization objective function;

[0186] The target path observation point set is subjected to path conversion to obtain an optimal earth observation path for the satellite to perform the task to be observed.

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

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

[0189] The memory may include a Random Access Memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located far from the aforementioned processor.

[0190] The above-mentioned processor may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0191] In another embodiment provided by the present invention, a computer-readable storage medium is further provided. A computer program is stored on the readable storage medium. When the computer program is executed by a processor, the satellite-to-ground observation path planning method described in any one of the above embodiments is implemented.

[0192] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part 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, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. 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 by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state disk (SSD)).

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

[0194] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and for related parts, reference can be made to the corresponding description in the method embodiments.

[0195] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A satellite earth observation path planning method, characterized in that: The method comprises: Obtain the orbit of the satellite to be executed, the shooting width and the mission to be observed; According to the orbit around the earth and the shooting width, the expected observation ground area is divided into a two-dimensional grid map containing a plurality of uniform squares, and the observation demand of the two-dimensional grid map is characterized according to the task to be observed; According to the time sequence change of the orbit around the earth, the two-dimensional grid diagram after the observation demand is characterized is stacked in time order to obtain a three-dimensional space-time grid; Searching for path observation points based on the three-dimensional space-time grid to obtain a target path observation point set that satisfies the minimization of a pre-constructed optimization objective function; Performing path conversion on the target path observation point set to obtain an optimal earth observation path for the satellite to perform the mission to be observed.

2. The method according to claim 1, characterized in that The method further comprises dividing the expected ground observation area into a two-dimensional grid map containing a plurality of uniform squares according to the orbit around the earth and the shooting width, and characterizing the observation requirements of the two-dimensional grid map according to the task to be observed, including: Determine the maximum observation area of ​​the satellite to be executed at each sub-satellite point according to the orbit around the earth, summarize the maximum observation areas of each sub-satellite point, and obtain an estimated ground observation area; Calculating the side length of the square grid to be divided according to the shooting width, and dividing the expected observation ground area into a two-dimensional grid map containing a plurality of uniform squares by using the side length of the square grid; Determine characterization parameters according to the task to be observed, and use the characterization parameters to characterize the observation requirements of the two-dimensional grid map.

3. The method according to claim 2, characterized in that The step of determining a characterization parameter according to the task to be observed, and using the characterization parameter to characterize the observation requirement of the two-dimensional grid graph includes: Extracting the geographical longitude and latitude of the target point and the urgency factor of the observation demand from the task to be observed; Generate characterization parameters according to the actual geographical longitude and latitude of the center of each square grid in the two-dimensional grid map, the geographical longitude and latitude of the target point, and the observation demand urgency factor; wherein the characterization parameters include the position coordinates of the square grid on the two-dimensional plane and the observation demand urgency factor; The characterization parameters are used to characterize the observation requirements of the square grids in the two-dimensional grid map.

4. The method according to claim 1, characterized in that: According to the time sequence change of the orbit around the earth, the two-dimensional grid diagram characterized by the observation demand is stacked in time order to obtain a three-dimensional space-time grid, including: Determining satellite visibility of a square grid in a two-dimensional grid map based on the time-series variation of the orbit around the earth; Based on the visibility of the square grid, the square grids in the two-dimensional grid map after the observation demand is represented are stacked in time order to obtain a three-dimensional space-time grid; wherein the three-dimensional space-time grid is represented as: ST(x,y,t)=A(x,y,t)κ(x,y) in, M represents the number of grids in the spatial grid size, K represents the time sequence number of the end point of the observation mission, 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 urgency factor of the observation demand.

5. The method according to claim 1, characterized in that The searching of path observation points based on the three-dimensional space-time grid to obtain a target path observation point set that satisfies the minimization of a pre-built optimization objective function includes: Pre-acquire the transfer benefit and transfer cost of the satellite between the observed grid nodes, and construct an optimization objective function using the transfer benefit and the transfer cost; The minimization of the optimization objective function is determined as the search target, and a path search is performed on each grid node in a forward expansion manner in the time dimension to obtain a target path observation point set.

6. The method according to claim 5, characterized in that The minimization of the optimization objective function is determined as the search target, and a path search is performed on each grid node in a forward expansion manner in the time dimension to obtain a target path observation point set, including: Determine a starting grid and an end grid, and determine the grid that minimizes the optimization objective function as the extended grid; Starting from the starting grid, the expanded grid is traversed and searched in a forward expansion manner in a time dimension, and visibility of the expanded grid is obtained; If the extended grid is visible and the optimization objective function at the extended grid is minimized, the extended grid is stored in a preset path observation point set; In the case where it is found that the extended grid coincides with the end point grid, the preset path observation point set is updated to the target path observation point set.

7. The method according to claim 5, characterized in that The transfer benefits and transfer costs of the satellite between the observed grid nodes are obtained in advance, and the optimization objective function is constructed using the transfer benefits and the transfer costs. The optimization objective function is expressed as: 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 the grid node, is the actual cost from the starting grid node to the current grid node, is the estimated cost from the current grid node to the target grid node, G i，i+1 represents the transfer benefit from the current grid node to the target grid node, β represents the grid task benefit factor, G i，i+1 Represents the transfer cost from the current grid node to the target grid node.

8. A satellite earth observation path planning device, characterized in that: The device comprises: The information acquisition module is used to obtain the orbit of the satellite to be executed, the shooting width and the mission to be observed; An observation requirement characterization module, used for dividing the expected observation ground area into a two-dimensional grid map containing a plurality of uniform squares according to the orbit around the earth and the shooting width, and performing observation requirement characterization on the two-dimensional grid map according to the task to be observed; A three-dimensional space-time grid module is used to stack the two-dimensional grid graphs characterized by the observation requirements in time order according to the time sequence changes of the orbit around the earth to obtain a three-dimensional space-time grid; A path search module, used to search for path observation points based on the three-dimensional space-time grid to obtain a target path observation point set that satisfies the minimization of a pre-built optimization objective function; The path conversion module 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 task to be observed.

9. An electronic device, characterized in that: include: processor; a memory for storing 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 7.

10. A readable storage medium, characterized in that: The readable storage medium stores a computer program, and when the computer program is executed by a processor, the satellite earth observation path planning method according to any one of claims 1 to 7 is implemented.

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