Fan-shaped earth observation target characterization method and system based on global discrete grid

Abstract

The invention relates to the technical field of satellite earth observation, in particular to a fan-shaped earth observation target characterization method based on global discrete grids, which comprises the following steps: S1, establishing a grid coverage template library which comprises grid coverage templates corresponding to circular targets with any radius and any grid level; s2, determining the longitude and latitude and the grid hierarchy of the circle center point of the fan-shaped earth observation target; s3, calling an adaptive grid coverage template, and covering the fan-shaped earth observation target; s4, removing an uncovered part of the fan-shaped earth observation target by the grid coverage template; and S5, recovering the broken grids into complete grids, and obtaining a grid unit set covering the fan-shaped earth observation target. Compared with the prior art, the characterization method for the fan-shaped earth observation target is more efficient, the grid coverage process is simplified in a mode of calling template coverage, the information processing efficiency is improved, and the actual application requirement can be better met.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite earth observation, and specifically to a method and system for representing earth observation targets in a fan shape based on a global discrete grid. Background Art

[0002] The global discrete grid system is a spherical-based earth body fitting grid that can be infinitely subdivided without changing its shape. When subdivided to a certain extent, it can achieve the purpose of simulating the earth's surface, and is expected to fundamentally solve problems such as data fracture, geometric deformation, and topological inconsistency in global space management and multi-scale operations of plane models. It can provide a continuous and globally unified analysis framework for fields such as remote sensing satellite scheduling management, UAV route planning, and meteorological prediction.

[0003] As a spatial identification method with a finite number of elements, the global discrete grid can effectively solve the problems faced in many current fields that require geographical information analysis. Using a finite grid code to replace the traditional infinite longitude and latitude coordinates can not only greatly reduce the complexity of the problem, but also make full use of data resources to meet user needs. The global discrete grid plays an important role in the process of representing earth observation targets. Using grid codes to represent the regional scope of targets is conducive to subsequent analysis and calculation based on the global discrete grid, improving the efficiency of geographical information processing to ensure meeting user requirements in terms of response time. Especially in large-scale remote sensing constellation earth coverage, when multiple satellites cooperate, task allocation needs to be carried out online. Calculating the coverage relationship between the field of view of the payload and the observation area based on traditional longitude and latitude requires numerical solution. By representing different payload field of view ranges and observation areas with a set of geographical grid codes and using the spatial indexing technology of grid codes, the coverage ratio relationship of different shapes of the payload field of view range and observation area can be quickly completed.

[0004] However, there is currently a lack of research on specific methods and efficiency improvement methods for using grids to represent earth observation targets. In particular, fan-shaped earth observation targets, including ordinary fans and circular fan shapes, are important forms of earth observation targets in many application fields. Existing methods usually require inputting a large number of longitude and latitude coordinates to describe the target area, which not only increases the complexity of preprocessing, but also leads to a burden in data storage and transmission. In addition, when converting grid codes back to regional geometric information, due to the huge number of grid codes, the reverse calculation is time-consuming. These problems indicate that we need a more efficient method to represent fan-shaped earth observation targets, reduce the amount of data, and improve calculation efficiency to better meet the actual application requirements. Summary of the Invention

[0005] The present invention provides a method and system for representing fan-shaped earth observation targets based on a global discrete grid to solve the problems raised in the above background art.

[0006] To achieve the above object, one aspect of the present invention provides the following technical solution: A method for characterizing a sector-shaped ground observation target based on a global discrete grid, comprising the following steps: S1. Establish a grid coverage template library, which includes grid coverage templates corresponding to circular targets with arbitrary radii and arbitrary grid levels; S2. Determine the longitude and latitude of the center point of the sector-shaped ground observation target and the grid level; S3. Call an adapted grid coverage template to cover the sector-shaped ground observation target; S4. Cut off the uncovered part of the grid coverage template for the sector-shaped ground observation target; S5. Restore the fragmented grid after cutting to a complete grid to obtain a set of grid cells covering the sector-shaped ground observation target.

[0007] Preferably, after inputting the radius and grid level of the circular shape, the grid coverage template library outputs the corresponding grid coverage template for calling.

[0008] Preferably, the grid level is used to characterize the size of a grid cell.

[0009] Preferably, step S3 specifically includes: Input the radius of the sector-shaped ground observation target and the preset grid level, call the corresponding grid coverage template from the grid coverage template library, and achieve coverage by aligning the center of the grid coverage template with the center point of the sector-shaped ground observation target.

[0010] Preferably, step S4 specifically includes: For a sector, cut off the grid coverage template according to the two radius boundaries of the sector.

[0011] Preferably, step S4 further includes: For an annulus sector, cut off the grid coverage template according to the two radius boundaries and the inner arc boundary of the annulus sector.

[0012] Preferably, step S5 specifically includes: In step S4, the grids intersecting the boundary are cut into fragmented grids, and the fragmented grids are restored to complete grids to obtain a set of grid cells covering the ground observation target.

[0013] Another aspect of the present invention provides a system for characterizing a sector-shaped ground observation target based on a global discrete grid, comprising: A grid coverage template library, which includes grid coverage templates corresponding to circular targets with arbitrary radii and arbitrary grid levels; A determination module, which is used for the longitude and latitude of the center point of the sector-shaped ground observation target and the grid level; A calling module, configured to call an adapted grid coverage template to cover the sector ground observation target; An excision module, configured to excise the uncovered part of the grid coverage template from the sector ground observation target; A restoration module, configured to restore the fragmented grids after cutting into complete grids to obtain a set of grid cells covering the sector ground observation target.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The method for representing a sector ground observation target based on a global discrete grid provided by the present invention establishes a grid coverage template library, which includes grid coverage templates corresponding to circular targets with arbitrary radii and arbitrary grid levels. In calculating the set of grid cells of the sector ground observation target, an adapted grid coverage template is called from the grid coverage template library according to the radius of the sector ground observation target, and the sector ground observation target is covered based on the longitude and latitude of the center point. Then, the uncovered part of the grid coverage template from the sector ground observation target is excised by the boundary, and finally, the fragmented grids intersecting at the boundary are restored into complete grids, thereby obtaining the set of grid cells of the ground observation target. Compared with the prior art, the representation method for the sector ground observation target provided by the present invention is more efficient. The process of grid coverage is simplified by the method of calling template coverage, the information processing efficiency is improved, and the actual application requirements can be better met. Description of the Drawings

[0015] Figure 1 It is a flowchart of the method for representing a sector ground observation target based on a global discrete grid provided by the present invention; Figure 2 It is a schematic diagram after covering with a grid coverage template for a sector provided by the present invention; Figure 3 It is a schematic diagram after covering with a grid coverage template for a sector ring provided by the present invention; Figure 4 It is a schematic diagram after excision of the grid coverage template for a sector provided by the present invention; Figure 5 It is a schematic diagram after excision of the grid coverage template for a sector ring provided by the present invention; Figure 6 It is a schematic diagram after restoration of the fragmented grids for a sector provided by the present invention; Figure 7 It is a schematic diagram after restoration of the fragmented grids for a sector ring provided by the present invention. Detailed Embodiments

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Figure 1 It is a flowchart of a method for representing a sector ground observation target based on a global discrete grid. An embodiment of the present invention provides a method for representing a sector ground observation target based on a global discrete grid. As Figure 1 shown, it includes the following steps: S1. Establish a grid coverage template library, where the grid coverage template library includes grid coverage templates corresponding to circular targets with any radius and any grid level; S2. Determine the longitude, latitude, and grid level of the center point of the sector ground observation target; S3. Call an adapted grid coverage template to cover the sector ground observation target; S4. Cut off the uncovered part of the grid coverage template for the sector ground observation target; S5. Restore the cut-up fragmented grids to complete grids to obtain a set of grid cells covering the sector ground observation target.

[0018] The grid cell coverage for circular targets is easily achievable in the art. On this basis, the present invention establishes a grid coverage template library for circular targets with any radius and any grid level. For the sector ground observation target, through steps such as calling the grid coverage template, cutting, and restoring fragmented grids, a set of grid cells covering the sector ground observation target can be obtained more quickly. Compared with the method of extracting multiple target vertices and performing grid coverage based on them in the prior art, the present invention only needs to obtain the longitude, latitude, and radius of the center point of the sector ground observation target to quickly achieve grid coverage. The process of grid coverage is simplified by the method of calling the template coverage, improving the information processing efficiency.

[0019] In the embodiment of the present invention, after inputting the radius and grid level of a circle, the grid coverage template library outputs the corresponding grid coverage template for calling.

[0020] In the embodiment of the present invention, specifically, the grid level is used to represent the size of a grid cell.

[0021] Figure 2 It is a schematic diagram after covering with the grid coverage template for the sector provided by the present invention, Figure 3 It is a schematic diagram after covering with the grid coverage template for the sector ring provided by the present invention. AsFigure 2 or Figure 3 As shown, in an embodiment of the present invention, step S3 specifically includes: Input the radius of the sector ground observation target and a preset grid level, call the corresponding grid coverage template from the grid coverage template library, and achieve coverage by aligning the center of the grid coverage template with the center point of the sector ground observation target.

[0022] The sector can include a common sector and an annular sector (i.e., a fan ring), which are uniformly referred to as the sector ground observation target in the embodiments of the present invention, and the same methods and steps are used for the characterization and processing of the sector and the fan ring. It should be noted that the radius of the fan ring is the radius of the base circle where its outer arc is located.

[0023] Figure 4 This is a schematic diagram of the grid coverage template for the sector provided by the present invention after excision. Figure 5 This is a schematic diagram of the grid coverage template for the fan ring provided by the present invention after excision. Further, as Figure 4 or Figure 5 shown, in an embodiment of the present invention, step S4 specifically includes: For the sector, cut the grid coverage template according to the two radius boundaries of the sector; For the fan ring, cut the grid coverage template according to the two radius boundaries and the inner arc boundary of the fan ring.

[0024] Through the above steps, quickly cut the grid coverage template according to the boundaries of the sector and the fan ring, so as to achieve the initial coverage of the sector and the fan ring.

[0025] Figure 6 This is a schematic diagram of the broken grid for the sector provided by the present invention after restoration. Figure 7 This is a schematic diagram of the broken grid for the fan ring provided by the present invention after restoration. Even further, as Figure 6 or Figure 7 shown, in an embodiment of the present invention, step S5 specifically includes: The grids intersecting with the boundary in step S4 are cut into broken grids, and the broken grids are restored into complete grids to obtain a set of grid units covering the sector ground observation target.

[0026] In the scenarios of any radius and any grid level, it is almost impossible for the grids in the grid coverage template to align with the boundaries of the sector and the fan ring. Therefore, after excision, there will inevitably be grids intersecting with the boundary cut into broken grids, which affect the integrity of the grid coverage. Therefore, by restoring these broken grids into complete grids, a set of grid units covering the sector ground observation target can be obtained.

[0027] It should be noted that the attached drawings of the present invention Figures 2 to 7 The sector in the drawings can be a polygon area on the sphere that is not projected onto the global discrete grid system, or a polygon area on the sphere projected onto the global discrete grid system. The attached drawings are only for easy understanding and do not necessarily mean that the processing is done on a plane. It can also be done on the sphere.

[0028] An embodiment of the present invention also provides a sector ground observation target characterization system based on a global discrete grid, including: A grid coverage template library, including grid coverage templates corresponding to circular targets with any radius and any grid level; A determination module, used to determine the longitude and latitude of the center point of the sector ground observation target and the grid level; A call module, used to call an adapted grid coverage template to cover the sector ground observation target; An excision module, used to excise the uncovered part of the grid coverage template for the sector ground observation target; A restoration module, used to restore the fragmented grids after cutting into complete grids to obtain a set of grid cells covering the ground observation target.

[0029] By establishing a grid coverage template library, in the calculation of the set of grid cells for the sector ground observation target, an adapted grid coverage template is called from the grid coverage template library based on the radius of the sector ground observation target, the sector ground observation target is covered based on the longitude and latitude of the center point, then the uncovered part of the grid coverage template for the sector ground observation target is excised by the boundary, and finally the fragmented grids intersecting at the boundary are restored into complete grids, thereby obtaining the set of grid cells for the ground observation target. Compared with the prior art, the characterization method for the sector ground observation target provided by the present invention is more efficient. The grid coverage process is simplified by the method of calling the template for coverage, the information processing efficiency is improved, and the actual application requirements can be better met.

[0030] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for representing earth observation targets in a fan shape based on a global discrete grid, characterized in that It includes the following steps: S1. Establish a grid coverage template library, which includes grid coverage templates corresponding to circular targets with arbitrary radii and arbitrary grid levels; S2. Determine the longitude, latitude and grid level of the center point of the fan-shaped earth observation target; S3. Call the adapted grid coverage template to cover the fan-shaped earth observation target; S4. Cut off the uncovered part of the grid coverage template for the fan-shaped earth observation target; S5. Restore the cut broken grids to complete grids to obtain a set of grid cells covering the fan-shaped earth observation target.

2. The method for representing a fan-shaped ground observation target based on a global discrete grid according to claim 1, wherein After the radius and grid level of the input circle are input into the grid coverage template library, the corresponding grid coverage template is output for calling.

3. The method for representing a sector ground observation target based on a global discrete grid according to claim 2, wherein The grid level is used to represent the size of a grid cell.

4. The method for representing a fan-shaped ground observation target based on a global discrete grid according to claim 3, wherein Step S3 specifically includes: Input the radius of the fan-shaped earth observation target and the preset grid level, call the corresponding grid coverage template from the grid coverage template library, and achieve coverage by aligning the center of the grid coverage template with the center point of the fan-shaped earth observation target.

5. The method for representing a fan-shaped ground observation target based on a global discrete grid according to claim 4, wherein Step S4 specifically includes: For a fan, cut off the grid coverage template according to the two radius boundaries of the fan.

6. The method for representing a fan-shaped ground observation target based on a global discrete grid according to claim 5, wherein Step S4 also includes: For a fan ring, cut off the grid coverage template according to the two radius boundaries and the inner arc boundary of the fan ring.

7. The method for representing a fan-shaped ground observation target based on a global discrete grid according to claim 6, wherein Step S5 specifically includes: In step S4, the grids intersecting with the boundary are cut into broken grids, and the broken grids are restored to complete grids to obtain a set of grid cells covering the fan-shaped earth observation target.

8. A fan-shaped earth observation target characterization system based on a global discrete grid, characterized in that It includes: A grid coverage template library, which includes grid coverage templates corresponding to circular targets with arbitrary radii and arbitrary grid levels; A determination module, which is used for the longitude, latitude and grid level of the center point of the fan-shaped earth observation target; A calling module, which is used to call the adapted grid coverage template to cover the fan-shaped earth observation target; A cutting-off module, which is used to cut off the uncovered part of the grid coverage template for the fan-shaped earth observation target; A restoration module, which is used to restore the cut broken grids to complete grids to obtain a set of grid cells covering the earth observation target grid.

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