A method for visualizing a coverage area of a cluster of beidou navigation satellites

Abstract

This invention relates to a method for visualizing coverage areas, specifically a method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites. The method includes: S1, acquiring ephemeris data; S2, calculating the nadir points of the BeiDou navigation satellites; S3, calculating all coverage boundary points of the BeiDou navigation satellites, fitting the data to form the coverage area of ​​the BeiDou navigation satellites; S4, obtaining the coverage areas of all BeiDou navigation satellites; S5, dividing the digital file of the Earth into multiple grid regions; S6, obtaining the coverage amount of each grid region; and S7, coloring the three-dimensional digital Earth according to the coverage amount of each grid region based on a mapping relationship, thereby visualizing the coverage area of ​​the cluster of BeiDou navigation satellites. This invention combines the calculation of the coverage area of ​​clustered BeiDou navigation satellites with three-dimensional visualization, enabling the calculation and visualization of the coverage area of ​​clustered BeiDou navigation satellites within any given time period, which helps in estimating the orbital trajectory of the clustered BeiDou navigation satellites.

Description

Technical Field

[0001] This invention relates to a method for visualizing coverage areas, specifically a method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites. Background Technology

[0002] The satellite navigation and location services industry is developing steadily. The digital transformation and intelligent upgrading of various industries continue to release rigid demand for satellite navigation equipment and spatiotemporal data, injecting strong development vitality into the BeiDou spatiotemporal information application and service market and promoting the steady growth of the overall economic benefits of the industry.

[0003] Currently, various basic algorithms and applications have been developed for satellite coverage analysis both domestically and internationally. The core of these algorithms is to determine satellite visibility by identifying the relative spatial position of satellite orbital parameters and ground target points. However, these basic algorithms and applications mostly focus on single satellite scenarios and are mainly used to count the continuous coverage duration of a single satellite over a specific area and to calculate the maximum and average time gaps during the coverage process. This not only limits their adaptability but also fails to meet the computational and visualization needs of cluster satellite coverage areas. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem that existing basic algorithms and applications for satellite coverage analysis cannot meet the computational and visualization requirements of clustered satellite coverage areas, and to provide a visualization method for the coverage areas of clustered BeiDou navigation satellites.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: A method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites includes the following steps: S1. Obtain the ephemeris data of each Beidou navigation satellite in the Beidou navigation system, and set the mission duration and the calculation step size of the nadir point; S2. Calculate the sub-satellite point of the Beidou navigation satellite according to the calculation step size within the set mission duration based on the ephemeris data of the Beidou navigation satellite; S3. Calculate all coverage boundary points of the BeiDou navigation satellite based on the swath width parameters of the BeiDou navigation satellite and the sub-satellite points obtained in step S2; The coverage area of ​​the BeiDou navigation satellite is formed by fitting all the coverage boundary points of the satellite. S4. Traverse all BeiDou navigation satellites and repeat steps S2 to S3 to obtain the coverage area of ​​all BeiDou navigation satellites; Store the coverage areas of all BeiDou navigation satellites in the PostGIS database according to the BeiDou navigation satellite numbers, and generate the data table zone_beidou; S5. Set the grid resolution and divide the digitized Earth file into multiple grid regions according to the grid resolution; S6. Record the coverage of each grid region as count, with an initial count value of 0; By comparing the coverage area in the data table zone_beidou with each grid area, if the coverage area covers the grid area, the coverage count is incremented by 1; otherwise, the count is incremented by 0. S7. Construct a 3D digital earth using the Cesuim engine and synchronize the grid areas divided in step S5. Establish a mapping relationship between grid area coverage and coloring degree; Based on the coverage of each grid area, the 3D digital earth is colored according to the mapping relationship to complete the visualization of the BeiDou navigation satellite coverage area.

[0006] Furthermore, in step S1, the BeiDou navigation satellite is a medium Earth orbit satellite in the BeiDou navigation system.

[0007] Furthermore, in step S2, the specific method for calculating the sub-satellite point of the BeiDou navigation satellite is as follows: S21. Calculate the angular velocity of BeiDou navigation satellites. : In the formula, n represents the average motion, measured in revolutions per day; S22. Calculate the mean anomaly angle M of the BeiDou navigation satellite: In the formula, Let t be the initial angle of approach, and t be the angle that changes at time t. S23. Calculate the near-point angle E of the BeiDou navigation satellite: E = M + e × sinE; S24. Calculate the true anomaly angle f of the BeiDou navigation satellite. ; S25. Calculate the sub-satellite point (λ) of the BeiDou navigation satellite. ),in: ; ; In the formula, λ and ω represents the longitude and latitude of the sub-satellite point, respectively; i is the orbital inclination; ω is the longitude of the ascending node; f is the true angle of approximation. The longitude of the initial ascending node; This is the Earth's rotational angular velocity.

[0008] Furthermore, in step S3, the specific method for fitting all the coverage boundary points of the BeiDou navigation satellite to form the coverage area of ​​the BeiDou navigation satellite is as follows: Create a point list st_line by arranging all the coverage boundary points of BeiDou navigation satellites in chronological order; The st_buffer function in the PostGIS database is used to fit all the coverage boundary points in the point list st_line and generate the coverage region Polygon. The st_buffer function is as follows: SELECT ST_Buffer(st_line,fk)::geometry(Polygon,3857) AS geom; In the function statement, fk is the swath width parameter of the BeiDou navigation satellite, in meters.

[0009] Furthermore, in step S4, the data table zone_beidou also contains id, satellite number satId, and coverage area geom; and the field formats of id, satellite number satId, and coverage area geom are Int, Varchar, and Geometry, respectively.

[0010] Furthermore, in step S6, the specific method for comparing the coverage area in the data table zone_beidou with each grid area is as follows: Construct a spatial index for the coverage area geom within the data table zone_beidou: CREATE INDEX idx_geom_gist ON zone_beidou USING GIST (geom); In the spatial index, idx_geom_gist is the index name, zone_beidou is the table name, and geom is the coverage area; The spatial index is used to sequentially retrieve the covering region geom corresponding to each grid region, and the ST_Within function is used to determine whether the grid region is covered by the covering region. If ST_Within(point, geom) = true, the coverage area covers the grid area, and the coverage count is incremented by 1; in the function, point is the grid area and geom is the coverage area; If ST_Within(point, geom) = false, the coverage area does not cover the grid area, and count is incremented by 0.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites. This method calculates the nadir points of the BeiDou navigation satellites based on their ephemeris data, and then calculates the coverage boundary points by combining this with the swath width parameters of the BeiDou navigation satellites. The coverage area of ​​the BeiDou navigation satellites is obtained through a fitting process. The digital file of the Earth is then divided into multiple grid regions, and the coverage of each grid region is colored according to the coverage area of ​​the BeiDou navigation satellites, thus visualizing the coverage area of ​​the cluster of BeiDou navigation satellites. Unlike coverage analysis of a single satellite or pure computational services, this invention combines the calculation of the coverage area of ​​a cluster of BeiDou navigation satellites with 3D visualization, enabling the calculation and visualization of the coverage area of ​​a cluster of BeiDou navigation satellites within any given time period. This helps in estimating the orbital trajectory of the cluster of BeiDou navigation satellites. Attached Figure Description

[0012] Figure 1 This is a visualization of the coverage distribution obtained in an embodiment of the present invention. Detailed Implementation

[0013] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] A method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites includes the following steps: 1) Obtain ephemeris data for each BeiDou navigation satellite within the BeiDou Navigation Satellite System. These BeiDou navigation satellites are the 24 third-generation medium Earth orbit satellites in the BeiDou Navigation Satellite System that provide location services to the ground. Ephemeris data can be obtained from the official BeiDou website. Example data is shown in the table below: ; The task duration is set to 4 hours, with a start time of 08:00:00 on September 8, 2025, and an end time of 12:00:00 on September 8, 2025. The calculation step size for the sub-satellite point is set to 60 seconds. 2) Calculate the sub-satellite points of the BeiDou navigation satellites according to the calculation step size within the set mission duration based on the ephemeris data of the BeiDou navigation satellites; Taking the BeiDou-3-M1 satellite in Table 1 as an example, the calculation method of the nadir point of BeiDou navigation satellites is explained in detail: 21) Extract the average motion n, orbital inclination i, and initial ascending node longitude from the ephemeris data of BeiDou-3-M1. Calculate the values ​​of the ascending node longitude ω and the horizontal anterior angle M, and convert them to the corresponding units of measurement. 22) Calculate the angular velocity of the BeiDou navigation satellite. : In the formula, n represents the average motion, measured in revolutions per day; 23) Calculate the mean anomaly angle M of the Beidou navigation satellite: In the formula, Let t be the initial angle of approach, and t be the angle that changes at time t. 24) Calculate the near-point angle E of the BeiDou navigation satellite: E = M + e × sinE; 25) Calculate the true anomaly angle f of the BeiDou navigation satellite. ; 26) Calculate the sub-satellite point (λ) of the BeiDou navigation satellite. ),in: ; ; In the formula, λ and ω represents the longitude and latitude of the sub-satellite point, respectively; i is the orbital inclination; ω is the longitude of the ascending node; f is the true angle of approximation. The longitude of the initial ascending node; This is the Earth's rotational angular velocity; 3) Calculate all coverage boundary points of the BeiDou navigation satellite based on the swath width parameters of the BeiDou navigation satellite and the sub-satellite points obtained in step S2; In this embodiment, the task lasts for 4 hours, and one nadir point is calculated every 60 seconds, resulting in a total of 240 nadir points, which are the latitude and longitude coordinates of 240 points. Create a point list st_line by arranging all the coverage boundary points of BeiDou navigation satellites in chronological order; The st_buffer function in the PostGIS database is used to fit all the coverage boundary points in the point list st_line and generate the coverage region Polygon. The st_buffer function is as follows: SELECT ST_Buffer(st_line,fk)::geometry(Polygon,3857) AS geom; In the function statement, fk is the swath width parameter of the BeiDou navigation satellite, in meters; 4) Traverse all BeiDou navigation satellites and repeat steps 2) to 3) to obtain the coverage area of ​​all BeiDou navigation satellites; The coverage areas of the 24 BeiDou navigation satellites are stored in the PostGIS database according to the satellite numbers, and a data table zone_beidou is generated. The data table zone_beidou also contains id, satellite number satId, and coverage area geom; and the field formats of id, satellite number satId, and coverage area geom are Int, Varchar, and Geometry, respectively; 5) Set the grid resolution and divide the digitized Earth file into multiple grid regions according to the grid resolution; 6) Record the coverage of each grid region as count, with an initial count value of 0; Construct a spatial index for the coverage area geom within the data table zone_beidou: CREATE INDEX idx_geom_gist ON zone_beidou USING GIST (geom); In the spatial index, idx_geom_gist is the index name, zone_beidou is the table name, and geom is the coverage area; The spatial index is used to sequentially retrieve the covering region geom corresponding to each grid region, and the ST_Within function is used to determine whether the grid region is covered by the covering region. If ST_Within(point, geom) = true, the coverage area covers the grid area, and the coverage count is incremented by 1; in the function, point is the grid area and geom is the coverage area; If ST_Within(point, geom) = false, the coverage area does not cover the grid area, and count is incremented by 0.

[0015] 7) Construct a 3D digital globe using the Cesuim engine and synchronize the grid areas divided in step 5); A mapping relationship is established between the coverage of the grid area and the degree of coloring. That is, the more coverage, the deeper the coloring. In this embodiment, the degree of coloring can be divided into 10 levels, corresponding to 10 different coverage intervals. Based on the coverage of each grid region, the 3D digital globe is colored according to the mapping relationship to complete the visualization of the BeiDou navigation satellite coverage area; the visualized coverage distribution map obtained in this embodiment is as follows. Figure 1 As shown.

[0016] The core code for the visualization method of the clustered BeiDou navigation satellite coverage area provided in this embodiment is as follows: coverAnalyze = xv.coverAnalyze; coverAnalyze.setProperty({ visible: true, lonStep:5, latStep:5, minLonAngle:-180, maxLonAngle: 180, minLatAngle: -90, maxLatAngle: 90, alpha: 0.7, colorStops: { 0:"#00ffff", 0.2:"#0088ff", 0.4:"#00ff00", 0.6:"#88ff00", 0.8:"#ffff00", 1.0:"#ff0000" }, data: finalData, showType: 'pdop', / / Type pdop satNum minWeight: 0, maxWeight: 10, minSatNum: 0, maxSatNum: maxSatNum, }) The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites, characterized in that, Includes the following steps: S1. Obtain the ephemeris data of each Beidou navigation satellite in the Beidou navigation system, and set the mission duration and the calculation step size of the nadir point; S2. Calculate the sub-satellite point of the Beidou navigation satellite according to the calculation step size within the set mission duration based on the ephemeris data of the Beidou navigation satellite; S3. Calculate all coverage boundary points of the BeiDou navigation satellite based on the swath width parameters of the BeiDou navigation satellite and the sub-satellite points obtained in step S2; The coverage area of ​​the BeiDou navigation satellite is formed by fitting all the coverage boundary points of the satellite. S4. Traverse all BeiDou navigation satellites and repeat steps S2 to S3 to obtain the coverage area of ​​all BeiDou navigation satellites; Store the coverage areas of all BeiDou navigation satellites in the PostGIS database according to the BeiDou navigation satellite numbers, and generate the data table zone_beidou; S5. Set the grid resolution and divide the digitized Earth file into multiple grid regions according to the grid resolution; S6. Record the coverage of each grid region as count, with an initial count value of 0; By comparing the coverage area in the data table zone_beidou with each grid area, if the coverage area covers the grid area, the coverage count is incremented by 1; otherwise, the count is incremented by 0. S7. Construct a 3D digital earth using the Cesuim engine and synchronize the grid areas divided in step S5. Establish a mapping relationship between grid area coverage and coloring degree; Based on the coverage of each grid area, the 3D digital earth is colored according to the mapping relationship to realize the visualization of the coverage area of ​​the clustered Beidou navigation satellites.

2. The method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites according to claim 1, characterized in that, In step S1, the BeiDou navigation satellite is a medium Earth orbit satellite in the BeiDou navigation system.

3. The method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites according to claim 1, characterized in that, In step S2, the specific method for calculating the sub-satellite point of the BeiDou navigation satellite is as follows: S21. Calculate the angular velocity of BeiDou navigation satellites. : In the formula, n represents the average motion, measured in revolutions per day; S22. Calculate the mean anomaly angle M of the BeiDou navigation satellite: In the formula, Let t be the initial angle of approach, and t be the angle that changes at time t. S23. Calculate the near-point angle E of the BeiDou navigation satellite: E = M + e × sinE; S24. Calculate the true anomaly angle f of the BeiDou navigation satellite. ; S25. Calculate the sub-satellite point (λ) of the BeiDou navigation satellite. ),in: ； ； In the formula, λ and ω represents the longitude and latitude of the sub-satellite point, respectively; i is the orbital inclination; ω is the longitude of the ascending node; f is the true angle of approximation. The longitude of the initial ascending node; This is the Earth's rotational angular velocity.

4. The method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites according to claim 1, characterized in that, In step S3, the specific method for fitting all the coverage boundary points of the BeiDou navigation satellite to form the coverage area of ​​the BeiDou navigation satellite is as follows: Create a point list st_line by arranging all the coverage boundary points of BeiDou navigation satellites in chronological order; The st_buffer function in the PostGIS database is used to fit all the coverage boundary points in the point list st_line and generate the coverage region Polygon. The st_buffer function is as follows: SELECT ST_Buffer(st_line,fk)::geometry(Polygon,3857) AS geom; In the function statement, fk is the swath width parameter of the BeiDou navigation satellite, in meters.

5. The method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites according to claim 1, characterized in that: In step S4, the data table zone_beidou also contains id, satellite number satId, and coverage area geom; and the field formats of id, satellite number satId, and coverage area geom are Int, Varchar, and Geometry, respectively.

6. The method for visualizing the coverage area of ​​a cluster of BeiDou navigation satellites according to claim 1, characterized in that, In step S6, the specific method for comparing the coverage area in the data table zone_beidou with each grid area is as follows: Construct a spatial index for the coverage area geom within the data table zone_beidou: CREATE INDEX idx_geom_gist ON zone_beidou USING GIST (geom); In the spatial index, idx_geom_gist is the index name, zone_beidou is the table name, and geom is the coverage area; The spatial index is used to sequentially retrieve the covering region geom corresponding to each grid region, and the ST_Within function is used to determine whether the grid region is covered by the covering region. If ST_Within(point, geom) = true, the coverage area covers the grid area, and the coverage count is incremented by 1; in the function, point is the grid area and geom is the coverage area; If ST_Within(point, geom) = false, the coverage area does not cover the grid area, and count is incremented by 0.

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