Nested grid based on-board fast extraction of overlapping regions method and system
By using a nested grid-based method, the overlapping area can be quickly extracted by calculating the intersection of satellite probe orbit and base map data. This solves the problems of low matching accuracy and computational redundancy in existing technologies, improves the efficiency of on-board data processing, and is suitable for detecting changes in on-orbit meteorological parameters.
Patent Information
- Application Number
- CN202610211940.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-13
- Publication Date
- 2026-06-26
AI Technical Summary
In existing technologies, the overlapping region extraction method of nested grids has low matching accuracy and computational redundancy in on-board processing, resulting in low data processing efficiency and failing to meet the needs of real-time meteorological parameter change detection.
By using a nested grid-based method, the periodic number of overlapping areas is determined by calculating the intersection of satellite orbits and base map data. Then, the positions of base map pixels are selected in the same latitude and longitude grid according to the proximity principle, so as to quickly extract the overlapping areas.
It improves the matching accuracy and computational efficiency of overlapping regions in nested grids, simplifies the processing flow of on-orbit change detection, and is suitable for the preprocessing flow of on-board change detection.
Smart Images
Figure CN122283772A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of on-orbit meteorological parameter change detection technology, specifically to a method and system for rapid on-board extraction of overlapping regions based on nested grids. Background Technology
[0002] In the field of meteorological observation, focusing on real-time meteorological parameter characteristic observation, acquiring parameter change characteristics, and monitoring such phenomena is highly beneficial for disaster monitoring, early warning, and prevention. The core idea of change detection is to capture the parameter characteristics of both the "past" and "present" times under the premise of "spatiotemporal alignment," and then analyze the changes in these parameter characteristics. Therefore, temporal and spatial registration is particularly important. Considering that the remote sensing data processed in real-time on-board is stored using an equal-view grid as the standard grid, while the base map data is pre-stored using an equal-latitude and longitude grid, the two types of grid division standards are different but also have some connection. For this type of nested grid problem, the problem of extracting overlapping areas must be considered first; otherwise, errors in the change detection results will be introduced, increasing redundant calculations in the on-board processing flow and affecting computational efficiency.
[0003] For overlapping region extraction during change detection, a common approach is to use the distance between two points as a standard for matching. However, if point-by-point matching is performed within the detection range, the matching accuracy cannot be improved, and there is computational redundancy, resulting in low on-board data processing efficiency. Therefore, it is necessary to propose a fast on-board method and system for extracting overlapping regions based on nested grids. This method utilizes the satellite's scanning cycle to quickly determine the location range of the detection points to be processed, and uses the boundary conditions of the base map data to obtain the location of the overlapping region. This simplifies the on-orbit change detection processing flow, ensuring computational accuracy while improving computational efficiency. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for rapid on-board extraction of overlapping regions based on nested meshes.
[0005] A method for fast on-board extraction of overlapping regions based on nested meshes, provided by the present invention, includes: Step S1: Calculate the boundary conditions of the base map based on the base map, and then obtain the intersection point between the base map and the probe orbit; Step S2: Determine the nadir trajectory based on the obtained satellite detection orbit range; Step S3: Calculate the intersection point between the nadir point trajectory and the base map; Step S4: Compare the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Step S5: Based on the boundary conditions of the base map, determine whether each satellite detection point is located within the extracted overlapping area within the period number range, and output the determination result; Step S6: For satellite probe points located within the extracted overlapping area, select the base map pixel position of the corresponding satellite probe point in the same latitude and longitude grid according to the proximity principle to complete the rapid extraction of the on-board overlapping area.
[0006] Preferably, step S1 includes: The data range is determined by the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude. Starting from the northernmost latitude endpoint, the endpoints are designated as the first to the fourth endpoints in a clockwise order. The boundary conditions of the base map data are determined by two adjacent endpoints and designated as the first to the fourth boundary conditions. The intersection points of the satellite probe orbit and the base map data are solved based on the satellite probe orbit position.
[0007] Preferably, let the four endpoints of the base map data be A(lonA, latA), B(lonB, latB), C(lonC, latC), and D(lonD, latD), corresponding to the first to fourth endpoints, then the first to fourth boundary conditions are as follows:
[0008] Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively:
[0009]
[0010] Based on the satellite probe orbit width and the number of probe points within the period, obtain the latitude and longitude positions of the first and last probe points within the period, and solve for the intersection point based on the above known boundary conditions.
[0011] Preferably, within the same detection cycle, different grid point positions correspond to different satellite observation angles. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude positions of the nadir point are obtained.
[0012] Preferably, step S4 includes: Satellite detection data is continuously updated along the satellite's direction of travel according to the scanning cycle. The scanning cycle number starts from the smallest number and increases continuously until one orbit of data detection is completed. In the payload scanning direction, there are several detection points based on the payload detection characteristics, numbered from the first to the last detection point. Each satellite detection point has a corresponding cycle number and a detection point number within the cycle. Based on the latitude and longitude of the intersection point, its corresponding cycle number is determined. According to the relationship between the number sizes, the start and end cycle numbers are finally determined as the range for extracting satellite detection points located in the overlapping area.
[0013] Preferably, step S6 includes: Using the proximity principle, the latitude and longitude position of the satellite detection point is used as the standard to find the latitude and longitude grid position closest to this position. That is, the position of the base map pixel corresponding to the detection point position is selected in the same latitude and longitude grid, the row and column number of the base map data is obtained, and the base map pixels that meet the conditions are filtered out, and finally the rapid extraction of the overlapping area on the satellite is completed.
[0014] A satellite-based system for rapid extraction of overlapping regions based on nested meshes, according to the present invention, includes: Module M1: Calculates the boundary conditions of the base map based on the base map, and then obtains the intersection point between the base map and the probe orbit; Module M2: Determines the nadir trajectory based on the acquired satellite detection orbit range; Module M3: Calculates the intersection point of the nadir point trajectory and the base map; Module M4: Compares the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Module M5: Based on the boundary conditions of the base map, it determines whether each satellite detection point is located within the extracted overlapping area within the period number range and outputs the determination result; Module M6: For satellite probes located within the range of the periodic number of the extracted overlapping area, the base map pixel position of the corresponding satellite probe is selected in the same latitude and longitude grid according to the proximity principle, so as to complete the rapid extraction of the on-board overlapping area.
[0015] Preferably, the module M1 includes: The data range is determined by the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude. Starting from the northernmost latitude endpoint, the endpoints are designated as the first to the fourth endpoints in a clockwise order. The boundary conditions of the base map data are determined by two adjacent endpoints and designated as the first to the fourth boundary conditions. The intersection points of the satellite probe orbit and the base map data are solved based on the satellite probe orbit position.
[0016] Preferably, let the four endpoints of the base map data be A(lonA, latA), B(lonB, latB), C(lonC, latC), and D(lonD, latD), corresponding to the first to fourth endpoints, then the first to fourth boundary conditions are as follows:
[0017] Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively:
[0018]
[0019] Based on the satellite probe orbit width and the number of probe points within the period, obtain the latitude and longitude positions of the first and last probe points within the period, and solve for the intersection point based on the above known boundary conditions.
[0020] Preferably, within the same detection cycle, different grid point positions correspond to different satellite observation angles. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude positions of the nadir point are obtained.
[0021] Preferably, the module M4 includes: Satellite detection data is continuously updated along the satellite's direction of travel according to the scanning cycle. The scanning cycle number starts from the smallest number and increases continuously until one orbit of data detection is completed. In the payload scanning direction, there are several detection points based on the payload detection characteristics, numbered from the first to the last detection point. Each satellite detection point has a corresponding cycle number and a detection point number within the cycle. Based on the latitude and longitude of the intersection point, its corresponding cycle number is determined. According to the relationship between the number sizes, the start and end cycle numbers are finally determined as the range for extracting satellite detection points located in the overlapping area.
[0022] Preferably, the module M6 includes: Using the proximity principle, the latitude and longitude position of the satellite detection point is used as the standard to find the latitude and longitude grid position closest to this position. That is, the position of the base map pixel corresponding to the detection point position is selected in the same latitude and longitude grid, the row and column number of the base map data is obtained, and the base map pixels that meet the conditions are filtered out, and finally the rapid extraction of the overlapping area on the satellite is completed.
[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention enables rapid extraction of overlapping regions in nested networks based on equal-view grids and equal-latitude and longitude grids, filling the technical gap of existing methods that use the distance between two points for point-by-point matching within the detection range, which cannot improve matching accuracy, and suffers from computational redundancy and low on-board data processing efficiency.
[0024] 2. In this invention, the location range of the detection point to be processed is quickly determined by utilizing the scanning cycle of satellite detection, and the location of the overlapping area is obtained by using the boundary conditions of the base map data. This simplifies the processing flow of on-orbit change detection, ensures calculation accuracy while improving calculation efficiency, and can be applied to the preprocessing flow of on-board change detection.
[0025] 3. This invention can be used in the research field of on-orbit meteorological parameter change detection, and can be used as a preprocessing technique for remote sensing data related to change detection, with a wide range of application scenarios. Attached Figure Description
[0026] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the working method of the present invention.
[0027] Figure 2 This is a schematic diagram of the overlapping area of satellite detection and base map in this invention. Detailed Implementation
[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0029] like Figure 1 As shown, a method for fast on-board extraction of overlapping regions based on nested meshes includes: Step S1: Calculate the boundary conditions of the base map based on the base map, and then obtain the intersection point between the base map and the probe orbit; Step S2: Determine the nadir trajectory based on the obtained satellite detection orbit range; Step S3: Calculate the intersection point between the nadir point trajectory and the base map; Step S4: Compare the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Step S5: Based on the boundary conditions of the base map, determine whether each satellite detection point is located within the extracted overlapping area within the period number range, and output the determination result; Step S6: For satellite probes located within the range of the periodic number of the extracted overlapping area, select the base map pixel position of the corresponding satellite probe in the same latitude and longitude grid according to the proximity principle to complete the rapid extraction of the on-board overlapping area.
[0030] In one specific embodiment, the above steps include: Step S1: Calculate the boundary conditions based on the range of the base map data, and then determine its intersection with the probe orbit. First, determine the data range using the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude, and in clockwise order, starting from the northernmost latitude endpoint, they are denoted as endpoints 1 to 4. Then, determine the boundary conditions of the base map data using two adjacent endpoints, denoted as boundary conditions 1 to 4 respectively. Finally, based on the position of the satellite probe orbit, solve for its intersection with the base map data.
[0031] Let the four endpoints of the base map data be A(lon) A lat A ), B (lon) B lat B ), C (lon C lat C ), D (lon) D lat D For endpoints 1 to 4, the boundary conditions for endpoints 1 to 4 are as follows:
[0032] Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively:
[0033]
[0034] Based on the satellite's orbital swath width and the number of probe points within the period, the latitude and longitude positions of the first and last probe points within the period are obtained. The intersection points are then calculated based on the known boundary conditions described above. The relative positions are as follows: Figure 2 As shown.
[0035] The nadir point trajectory is determined based on the satellite's orbital range. Utilizing this orbital range, and considering that the onboard resampled data is distributed in a grid with equal viewing angles within the orbital range, different grid points correspond to different satellite observation angles for the same observation cycle. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude of the nadir point are obtained.
[0036] Step S2: Utilizing the satellite's detection orbit range, considering that the on-board resampling data is distributed in an equal-view grid within the detection orbit range, different grid point positions correspond to different satellite observation angles for the same detection cycle. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude positions of the nadir point are obtained.
[0037] Step S3: Using the trajectory of the nadir point, calculate its intersection with the base map data, i.e., with boundary conditions 1 to 4. The principle is similar to step S1; using the latitude and longitude of the nadir point, the intersection with the known boundary conditions is solved. The relative positions are as follows: Figure 2 As shown.
[0038] Step S4: Using the intersection of the probe orbit and the base map, and the intersection of the nadir point trajectory and the base map, determine the start and end cycle numbers for extracting the overlapping area based on the scanning cycle number of each intersection point.
[0039] Satellite data is continuously updated along the satellite's path of travel according to a scanning cycle. Therefore, the scanning cycle number starts from 1 and increases continuously until one orbit's data acquisition is complete. In the payload scanning direction (generally the cross-orbit direction), there are several detection points based on the payload's detection characteristics, numbered from 1 to the last detection point. Each satellite detection point has a corresponding cycle number and a detection point number within that cycle. Based on the latitude and longitude of the intersection point, its corresponding cycle number can be determined. Following the relationship between the numbering, the start and end cycle numbers are ultimately determined, serving as the range for extracting satellite detection points located in the overlapping region.
[0040] Step S5: Using the first to fourth boundary conditions of the base map data and the satellite detection cycle number range, for each satellite detection point, determine whether it is located in the overlapping area, and then filter out the satellite detection points located in the overlapping area.
[0041] For satellite detection points, directly select detection points within the specified period number range, determine whether each point is within the boundary, and filter out satellite detection points that meet the conditions.
[0042] Step S6: Based on the location of the probe points in the overlapping region, considering that the satellite probe points are distributed in an equal-view grid while the base map pixels are distributed in an equal-latitude and longitude grid, the nearest latitude and longitude grid location is found using the proximity principle, taking the latitude and longitude location of the satellite probe point as the standard. That is, the base map pixel location corresponding to the probe point location is selected in the equal-latitude and longitude grid, the row and column numbers of the base map data are obtained, and the base map pixels that meet the conditions are filtered out, thus completing the rapid extraction of the on-board overlapping region.
[0043] The present invention also provides a system for rapid on-board extraction of overlapping regions based on nested meshes. The system for rapid on-board extraction of overlapping regions based on nested meshes can be implemented by executing the process steps of the method for rapid on-board extraction of overlapping regions based on nested meshes. That is, those skilled in the art can understand the method for rapid on-board extraction of overlapping regions based on nested meshes as a preferred embodiment of the system for rapid on-board extraction of overlapping regions based on nested meshes.
[0044] Specifically, a satellite-based system for rapid extraction of overlapping regions based on nested meshes includes: Module M1: Calculates the boundary conditions of the base map based on the base map, and then obtains the intersection point between the base map and the probe orbit; Module M2: Determines the nadir trajectory based on the acquired satellite detection orbit range; Module M3: Calculates the intersection point of the nadir point trajectory and the base map; Module M4: Compares the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Module M5: Based on the boundary conditions of the base map, it determines whether each satellite detection point is located within the extracted overlapping area within the period number range and outputs the determination result; Module M6: For satellite probes located within the range of the periodic number of the extracted overlapping area, the base map pixel position of the corresponding satellite probe is selected in the same latitude and longitude grid according to the proximity principle, so as to complete the rapid extraction of the on-board overlapping area.
[0045] The module M1 includes: The data range is determined by the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude. Starting from the northernmost latitude endpoint, the endpoints are designated as the first to the fourth endpoints in a clockwise order. The boundary conditions of the base map data are determined by two adjacent endpoints and designated as the first to the fourth boundary conditions. The intersection points of the satellite probe orbit and the base map data are solved based on the satellite probe orbit position.
[0046] Let the four endpoints of the base map data be A(lonA, latA), B(lonB, latB), C(lonC, latC), and D(lonD, latD), corresponding to the first to fourth endpoints, then the first to fourth boundary conditions are as follows:
[0047] Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively:
[0048]
[0049] Based on the satellite probe orbit width and the number of probe points within the period, obtain the latitude and longitude positions of the first and last probe points within the period, and solve for the intersection point based on the above known boundary conditions.
[0050] In the same detection cycle, different grid points correspond to different satellite observation angles. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude of the nadir point are obtained.
[0051] The module M4 includes: Satellite detection data is continuously updated along the satellite's direction of travel according to the scanning cycle. The scanning cycle number starts from the smallest number and increases continuously until one orbit of data detection is completed. In the payload scanning direction, there are several detection points based on the payload detection characteristics, numbered from the first to the last detection point. Each satellite detection point has a corresponding cycle number and a detection point number within the cycle. Based on the latitude and longitude of the intersection point, its corresponding cycle number is determined. According to the relationship between the number sizes, the start and end cycle numbers are finally determined as the range for extracting satellite detection points located in the overlapping area.
[0052] The module M6 includes: Using the proximity principle, the latitude and longitude position of the satellite detection point is used as the standard to find the latitude and longitude grid position closest to this position. That is, the position of the base map pixel corresponding to the detection point position is selected in the same latitude and longitude grid, the row and column number of the base map data is obtained, and the base map pixels that meet the conditions are filtered out, and finally the rapid extraction of the overlapping area on the satellite is completed.
[0053] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.
[0054] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.
Claims
1. A method for fast on-board extraction of overlapping regions based on nested meshes, characterized in that, include: Step S1: Calculate the boundary conditions of the base map based on the base map, and then obtain the intersection point between the base map and the probe orbit; Step S2: Determine the nadir trajectory based on the obtained satellite detection orbit range; Step S3: Calculate the intersection point between the nadir point trajectory and the base map; Step S4: Compare the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Step S5: Based on the boundary conditions of the base map, determine whether each satellite detection point is located within the extracted overlapping area within the period number range, and output the determination result; Step S6: For satellite probes located within the range of the periodic number of the extracted overlapping area, select the base map pixel position of the corresponding satellite probe in the same latitude and longitude grid according to the proximity principle to complete the rapid extraction of the on-board overlapping area.
2. The method for rapid on-board extraction of overlapping regions based on nested meshes according to claim 1, characterized in that, Step S1 includes: The data range is determined by the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude. Starting from the northernmost latitude endpoint, the endpoints are designated as the first to the fourth endpoints in a clockwise order. The boundary conditions of the base map data are determined by two adjacent endpoints and designated as the first to the fourth boundary conditions. The intersection points of the satellite probe orbit and the base map data are solved based on the satellite probe orbit position.
3. The method for rapid on-board extraction of overlapping regions based on nested meshes according to claim 2, characterized in that, Let the four endpoints of the base map data be A(lonA, latA), B(lonB, latB), C(lonC, latC), and D(lonD, latD), corresponding to the first to fourth endpoints, then the first to fourth boundary conditions are as follows: Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively: Based on the satellite probe orbit width and the number of probe points within the period, obtain the latitude and longitude positions of the first and last probe points within the period, and solve for the intersection point based on the above known boundary conditions.
4. The method for rapid on-board extraction of overlapping regions based on nested meshes according to claim 1, characterized in that, In the same detection cycle, different grid points correspond to different satellite observation angles. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude of the nadir point are obtained.
5. The method for rapid on-board extraction of overlapping regions based on nested meshes according to claim 3, characterized in that, Step S4 includes: Satellite detection data is continuously updated along the satellite's direction of travel according to the scanning cycle. The scanning cycle number starts from the smallest number and increases continuously until one orbit of data detection is completed. In the payload scanning direction, there are several detection points based on the payload detection characteristics, numbered from the first to the last detection point. Each satellite detection point has a corresponding cycle number and a detection point number within the cycle. Based on the latitude and longitude of the intersection point, its corresponding cycle number is determined. According to the relationship between the number sizes, the start and end cycle numbers are finally determined as the range for extracting satellite detection points located in the overlapping area.
6. The method for rapid on-board extraction of overlapping regions based on nested meshes according to claim 1, characterized in that, Step S6 includes: Using the proximity principle, the latitude and longitude position of the satellite detection point is used as the standard to find the latitude and longitude grid position closest to this position. That is, the position of the base map pixel corresponding to the detection point position is selected in the same latitude and longitude grid, the row and column number of the base map data is obtained, and the base map pixels that meet the conditions are filtered out, and finally the rapid extraction of the overlapping area on the satellite is completed.
7. A system for rapid on-board extraction of overlapping regions based on nested meshes, characterized in that, include: Module M1: Calculates the boundary conditions of the base map based on the base map, and then obtains the intersection point between the base map and the probe orbit; Module M2: Determines the nadir trajectory based on the acquired satellite detection orbit range; Module M3: Calculates the intersection point of the nadir point trajectory and the base map; Module M4: Compares the intersection points of the base map and the probe orbit, as well as the intersection points of the nadir point trajectory and the base map, to obtain the period number of the extracted overlapping region; the period number of the extracted overlapping region includes the start period number and the end period number; Module M5: Based on the boundary conditions of the base map, it determines whether each satellite detection point is located within the extracted overlapping area within the period number range and outputs the determination result; Module M6: For satellite probes located within the range of the periodic number of the extracted overlapping area, the base map pixel position of the corresponding satellite probe is selected in the same latitude and longitude grid according to the proximity principle, so as to complete the rapid extraction of the on-board overlapping area.
8. The on-board rapid overlapping region extraction system based on nested meshes according to claim 7, characterized in that, The module M1 includes: The data range is determined by the four endpoints of the base map data. The base map data is distributed in a grid of equal latitude and longitude. Starting from the northernmost latitude endpoint, the endpoints are designated as the first to the fourth endpoints in a clockwise order. The boundary conditions of the base map data are determined by two adjacent endpoints and designated as the first to the fourth boundary conditions. The intersection points of the satellite probe orbit and the base map data are solved based on the satellite probe orbit position.
9. The on-board rapid overlapping region extraction system based on nested meshes according to claim 8, characterized in that, Let the four endpoints of the base map data be A(lonA, latA), B(lonB, latB), C(lonC, latC), and D(lonD, latD), corresponding to the first to fourth endpoints, then the first to fourth boundary conditions are as follows: Where i takes values from 1 to 4. and These represent the coefficients in the i-th boundary condition, respectively: Based on the satellite probe orbit width and the number of probe points within the period, obtain the latitude and longitude positions of the first and last probe points within the period, and solve for the intersection point based on the above known boundary conditions.
10. The on-board rapid overlapping region extraction system based on nested meshes according to claim 7, characterized in that, In the same detection cycle, different grid points correspond to different satellite observation angles. The position with an observation angle of 0° is selected as the nadir point trajectory, and the latitude and longitude of the nadir point are obtained.