A Method and System for Characterizing Sector-Shaped Earth Observation Targets Based on Global Discrete Grid

Abstract

This invention relates to the field of satellite Earth observation technology, specifically a method for characterizing sector-shaped Earth observation targets based on a global discrete grid. The method includes the following steps: S1, establishing a grid coverage template library, which includes grid coverage templates corresponding to circular targets of arbitrary radius and grid level; S2, determining the latitude and longitude of the center point of the sector-shaped Earth observation target and the grid level; S3, calling the appropriate grid coverage template to cover the sector-shaped Earth observation target; S4, cutting off the uncovered portion of the sector-shaped Earth observation target covered by the grid coverage template; S5, restoring the broken grid to a complete grid, obtaining a set of grid cells covering the sector-shaped Earth observation target. Compared to existing technologies, the characterization method for sector-shaped Earth observation targets provided by this invention is more efficient. By using templates for coverage, the grid coverage process is simplified, information processing efficiency is improved, and it can better meet practical application needs.

Description

Technical Field

[0001] This invention relates to the field of satellite Earth observation technology, specifically to a method and system for characterizing sector-shaped Earth observation targets based on a global discrete grid. Background Technology

[0002] The global discrete grid system is a sphere-based Earth-fitting grid that can be infinitely subdivided without changing its shape. When subdivided to a certain extent, it can simulate the Earth's surface and is expected to fundamentally solve problems such as data fragmentation, geometric deformation, and topological inconsistency in global spatial management and multi-scale operations of planar models. It can provide a continuous and globally unified analysis framework for fields such as remote sensing satellite scheduling and management, UAV flight path planning, and weather forecasting.

[0003] Global discrete grids, as a spatial identification method with a finite number of cells, can effectively solve many challenges faced in fields requiring geographic information analysis. Replacing traditional infinite latitude and longitude coordinates with finite grid coding not only significantly reduces problem complexity but also fully utilizes data resources to meet user needs. Global discrete grids play a crucial role in representing Earth observation targets. Using grid coding to represent the regional extent of targets facilitates subsequent analysis and calculations based on the global discrete grid, improving the efficiency of geographic information processing and ensuring that user response time requirements are met. Especially in large-scale remote sensing constellations covering the Earth, online task allocation is required during multi-satellite collaboration. Traditional latitude and longitude calculations of the payload's field of view and the coverage relationship of the observation area require numerical solutions. However, by uniformly representing the payload's field of view and the observation area using a single geographic grid code, and utilizing the spatial indexing technology of the grid code, the coverage ratio relationship of the payload's field of view and the observation area of ​​different shapes can be quickly determined.

[0004] However, current research lacks specific methods and efficiency improvement techniques for representing Earth observation targets using grids. In particular, sector-shaped Earth observation targets, including ordinary sectors and annular sectors, are important target types in many application fields. Existing methods typically require a large number of latitude and longitude coordinates to describe the target area, which not only increases the complexity of preprocessing but also burdens data storage and transmission. Furthermore, converting grid codes back to regional geometric information is time-consuming due to the sheer number of grid codes. These issues indicate a need for a more efficient method to represent sector-shaped Earth observation targets, reducing data volume and improving computational efficiency to better meet practical application needs. Summary of the Invention

[0005] This invention provides a method and system for characterizing sector-shaped Earth observation targets based on a global discrete grid, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, one aspect of the present invention provides the following technical solution:

[0007] The method for characterizing sector-shaped Earth observation targets based on a global discrete grid includes the following steps:

[0008] S1. Establish a grid coverage template library, which includes grid coverage templates corresponding to circular targets of arbitrary radius and arbitrary grid level;

[0009] S2. Determine the latitude, longitude, latitude, and grid level of the center point of the sector-shaped Earth observation target;

[0010] S3. Invoke the appropriate grid coverage template to cover the fan-shaped Earth observation target;

[0011] S4. Cut off the uncovered portion of the fan-shaped Earth observation target by the grid coverage template;

[0012] S5. Restore the broken grid after cutting to a complete grid to obtain a set of grid cells covering the fan-shaped Earth observation target.

[0013] Preferably, after inputting the radius of the circle and the grid level, the grid cover template library outputs the corresponding grid cover template for use.

[0014] Preferably, the grid hierarchy is used to characterize the size of a grid cell.

[0015] Preferably, step S3 specifically includes:

[0016] 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.

[0017] Preferably, step S4 specifically includes:

[0018] For a sector, the mesh cover template is cut off based on the two radius boundaries of the sector.

[0019] Preferably, step S4 further includes:

[0020] For the sector ring, the mesh cover template is cut off based on the two radius boundaries and the inner arc boundary of the sector ring.

[0021] Preferably, step S5 specifically includes:

[0022] In step S4, the grids intersecting the boundary are cut into broken grids, and the broken grids are restored into complete grids to obtain a set of grid cells covering the Earth observation target.

[0023] Another aspect of the present invention provides a sector-shaped Earth observation target characterization system based on a global discrete grid, comprising:

[0024] A mesh overlay template library, including mesh overlay templates for circular targets of any radius and any mesh level;

[0025] The module is used to determine the latitude, longitude, and grid level of the center point of the sector-shaped Earth observation target;

[0026] The calling module is used to call the adapted grid coverage template to cover the fan-shaped Earth observation target;

[0027] The cut-off module is used to cut off the uncovered portion of the grid coverage template of the sector-shaped Earth observation target;

[0028] The recovery module is used to restore the cut and broken grid to a complete grid, thereby obtaining a set of grid cells covering the fan-shaped Earth observation target.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The present invention provides a method for characterizing sector-shaped Earth observation targets based on a global discrete grid. This method establishes a grid coverage template library, which includes grid coverage templates corresponding to circular targets of arbitrary radius and grid level. In calculating the set of grid cells for the sector-shaped Earth observation target, a suitable grid coverage template is retrieved from the library based on the radius of the target. The target is then covered based on the latitude and longitude of its center point. The uncovered portions of the target are then removed by cutting off the grid coverage templates at the boundaries. Finally, the broken grids at the boundary intersections are restored to complete grids, thus obtaining the set of grid cells for the Earth observation target. Compared to existing technologies, the characterization method for sector-shaped Earth observation targets provided by this invention is more efficient. The template-based coverage method simplifies the grid coverage process, improves information processing efficiency, and better meets practical application needs. Attached Figure Description

[0031] Figure 1 A flowchart of the sector-shaped Earth observation target characterization method based on a global discrete grid provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the fan-shaped grid covering template provided by the present invention after coverage;

[0033] Figure 3 This is a schematic diagram of the grid covering template for the fan ring provided by the present invention after coverage;

[0034] Figure 4This is a schematic diagram of the fan-shaped mesh covering template after it has been cut off, as provided by the present invention.

[0035] Figure 5 This is a schematic diagram of the mesh covering template for the fan ring after it has been cut off, as provided by the present invention.

[0036] Figure 6 This is a schematic diagram of the restored fan-shaped broken mesh provided by the present invention;

[0037] Figure 7 This is a schematic diagram of the restored broken mesh of the fan ring provided by the present invention. Detailed Implementation

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Figure 1 This is a flowchart of a sector-shaped Earth observation target characterization method based on a global discrete grid. Embodiments of this invention provide a sector-shaped Earth observation target characterization method based on a global discrete grid, such as... Figure 1 As shown, it includes the following steps:

[0040] S1. Establish a grid coverage template library, which includes grid coverage templates corresponding to circular targets of arbitrary radius and arbitrary grid level;

[0041] S2. Determine the latitude, longitude, latitude, and grid level of the center point of the sector-shaped Earth observation target;

[0042] S3. Invoke the appropriate grid coverage template to cover the fan-shaped Earth observation target;

[0043] S4. Cut off the uncovered portion of the fan-shaped Earth observation target by the grid coverage template;

[0044] S5. Restore the broken grid after cutting to a complete grid to obtain a set of grid cells covering the fan-shaped Earth observation target.

[0045] Mesh cell coverage for circular targets is readily achievable in this field. Building upon this, this invention establishes a mesh coverage template library for circular targets of arbitrary radius and mesh level. For sector-shaped Earth observation targets, by calling mesh coverage templates and performing steps such as cutting and restoring fragmented meshes, a set of mesh cells covering the sector-shaped Earth observation target can be obtained more quickly. Compared to the existing technology that extracts multiple target vertices and uses them as a basis for mesh coverage, this invention only needs to obtain the latitude, longitude, and radius of the center point of the sector-shaped Earth observation target to quickly achieve mesh coverage. The method of calling templates simplifies the mesh coverage process and improves information processing efficiency.

[0046] In an embodiment of the present invention, the mesh overlay template library outputs a corresponding mesh overlay template for use after inputting the radius of the circle and the mesh level.

[0047] In an embodiment of the present invention, specifically, the grid hierarchy is used to characterize the size of a grid cell.

[0048] Figure 2 This is a schematic diagram showing the effect of the grid covering template for a fan-shaped area after being covered, as provided by the present invention. Figure 3 This is a schematic diagram showing the grid covering template for the fan ring provided by the present invention after coverage. Figure 2 or Figure 3 As shown, in an embodiment of the present invention, step S3 specifically includes:

[0049] 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.

[0050] The sector can include ordinary sectors and annular sectors (i.e., sector rings), which are uniformly referred to as sector-shaped Earth observation targets in the embodiments of this invention, and the same methods and steps are used to characterize sectors and sector rings. It should be noted that the radius of the sector ring is the radius of the base circle containing its outer arc.

[0051] Figure 4 This is a schematic diagram of the fan-shaped mesh covering template after it has been cut, as provided by the present invention. Figure 5 This is a schematic diagram of the mesh covering template for the fan ring provided by the present invention after it has been cut off. Further, as... Figure 4 or Figure 5 As shown, in an embodiment of the present invention, step S4 specifically includes:

[0052] For a sector, the mesh cover template is cut off based on the two radius boundaries of the sector;

[0053] For the sector ring, the mesh cover template is cut off based on the two radius boundaries and the inner arc boundary of the sector ring.

[0054] Through the above steps, the grid covering template is quickly cut off according to the boundaries of the sector and sector ring, thereby achieving preliminary coverage of the sector and sector ring.

[0055] Figure 6 This is a schematic diagram of the restored fan-shaped broken mesh provided by the present invention. Figure 7 This is a schematic diagram illustrating the restored broken mesh of a fan-shaped ring according to the present invention. Furthermore, as... Figure 6 or Figure 7 As shown, in an embodiment of the present invention, step S5 specifically includes:

[0056] In step S4, the grids intersecting 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.

[0057] In scenarios with arbitrary radius and arbitrary grid level, it is almost impossible for the grid in the grid coverage template to align with the boundaries of the sector and sector ring. Therefore, after cutting, the grids intersecting the boundaries will inevitably be cut into broken grids. These broken grids affect the integrity of the grid coverage. Therefore, by restoring these broken grids into complete grids, the set of grid cells covering the sector-shaped Earth observation target can be obtained.

[0058] It should be noted that the appendix to this invention specification... Figures 2 to 7 The sector in the figure can be a polygonal region on a sphere that is not projected onto the global discrete grid system, or it can be a polygonal region projected onto the sphere of the global discrete grid system. The attached figure is only for the purpose of understanding and does not necessarily mean that the processing is done on a plane. It can also be done on a sphere.

[0059] Embodiments of the present invention also provide a sector-shaped Earth observation target characterization system based on a global discrete grid, comprising:

[0060] A mesh overlay template library, including mesh overlay templates for circular targets of any radius and any mesh level;

[0061] The module is used to determine the latitude, longitude, and grid level of the center point of the sector-shaped Earth observation target;

[0062] The calling module is used to call the adapted grid coverage template to cover the fan-shaped Earth observation target;

[0063] The cut-off module is used to cut off the uncovered portion of the grid coverage template of the sector-shaped Earth observation target;

[0064] The recovery module is used to restore the cut and broken grid to a complete grid, thereby obtaining a set of grid cells covering the Earth observation target.

[0065] This invention establishes a grid coverage template library. In calculating the grid cell set for a sector-shaped Earth observation target, the appropriate grid coverage template is called from the library based on the radius of the sector-shaped Earth observation target. The target is then covered based on the latitude and longitude of the center point. The uncovered portion of the target is then removed by cutting off the grid coverage template at the boundary. Finally, the broken grids at the boundary intersections are restored to complete grids, thus obtaining the grid cell set of the Earth observation target. Compared to existing technologies, the representation method for sector-shaped Earth observation targets provided by this invention is more efficient. The template-based coverage method simplifies the grid coverage process, improves information processing efficiency, and better meets practical application needs.

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for characterizing sector-shaped Earth observation targets based on a global discrete grid, characterized in that, Includes the following steps: S1. Establish a grid coverage template library, which includes grid coverage templates corresponding to circular targets of arbitrary radius and arbitrary grid level; S2. Determine the latitude, longitude, latitude, and grid level of the center point of the sector-shaped Earth observation target; S3. Invoke the appropriate grid coverage template to cover the fan-shaped Earth observation target; S4. Cut off the uncovered portion of the fan-shaped Earth observation target by the grid coverage template; S5. Restore the broken grid after cutting to a complete grid to obtain a set of grid cells covering the fan-shaped Earth observation target; 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; Step S4 specifically includes: For a sector, the mesh cover template is cut off based on the two radius boundaries of the sector; Step S4 also includes: For the sector ring, the mesh cover template is cut off based on the two radius boundaries and the inner arc boundary of the sector ring; Step S5 specifically includes: In step S4, the grids intersecting 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.

2. The method for characterizing sector-shaped Earth observation targets based on a global discrete grid according to claim 1, characterized in that, The grid overlay template library outputs the corresponding grid overlay template for use after inputting the radius of the circle and the grid level.

3. The method for characterizing sector-shaped Earth observation targets based on a global discrete grid according to claim 2, characterized in that, The grid hierarchy is used to characterize the size of a grid cell.

4. A sector-shaped Earth observation target characterization system based on a global discrete grid, characterized in that, include: A mesh overlay template library, including mesh overlay templates for circular targets of any radius and any mesh level; The module is used to determine the latitude, longitude, and grid level of the center point of the sector-shaped Earth observation target; The calling module is used to call the adapted grid coverage template to cover the fan-shaped Earth observation target; 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; The cutting module is used to cut off the uncovered portion of the grid coverage template of the sector-shaped Earth observation target; for the sector, the grid coverage template is cut off according to the two radius boundaries of the sector; For the sector ring, the mesh cover template is cut off based on the two radius boundaries and the inner arc boundary of the sector ring; The recovery module is used to restore the cut and fragmented grid to a complete grid, thereby obtaining a set of grid cells covering the Earth observation target. The mesh that intersects with the boundary is cut into a broken mesh, and the broken mesh is restored to a complete mesh.

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