Satellite ground coverage and target visibility calculation method

Abstract

The present application relates to a kind of calculation methods for satellite ground field of view coverage and ground target visibility, comprising: S1: satellite field of view mode is divided into two, respectively mode 0 and mode 1, wherein mode 0 is referred to as subsatellite point mode, mode 1 is referred to as pointing to certain ground fixed point mode;S2: in mode 0 case, satellite is opposite subsatellite point, calculate satellite ground field of view range and ground target visibility;S3: in mode 1 case, satellite is opposite certain ground fixed point, certain ground fixed point is not subsatellite point, calculate satellite ground field of view range and ground target visibility.The present application calculation method selects satellite pointing subsatellite point or specific ground point mode, solves the problem of calculating satellite pointing certain ground point field of view range and ground target visibility by coordinate transformation and rodrigo rotation matrix.

Description

Technical Field

[0001] This invention relates to a method for calculating the coverage of a satellite's field of view and the visibility of ground targets, belonging to the field of satellite Earth observation technology. Background Technology

[0002] With the advent of information-based and intelligent living, satellite applications are becoming increasingly widespread in modern life, playing an increasingly important role in competition. Calculating satellite field-of-view coverage and ground target visibility can help us rationally maneuver satellites to achieve coverage of target areas at minimal cost, thereby improving reconnaissance (communication) efficiency.

[0003] Current methods for calculating the field of view of satellites focus on the scenario where the satellite is looking directly at the point below it, which does not match the actual application scenario where the satellite is pointing at a point on the ground. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for calculating the coverage range of a satellite's field of view and the visibility of ground targets. By selecting a satellite pointing to a nadir point or a specific ground point mode, and through coordinate transformation and Rodrigo rotation matrix, the problem of calculating the field of view range of a satellite pointing to a certain ground point and the visibility of ground targets is solved.

[0005] The technical solution of this invention is: A method for calculating the coverage range of a satellite's field of view and the visibility of ground targets includes: The satellite field of view is divided into two modes: mode 0 and mode 1. Mode 0 refers to the nadir mode, while mode 1 refers to the mode pointing to a fixed point on the ground. In Mode 0, the satellite is directly facing the nadir point, and the satellite's field of view and the visibility of ground targets are calculated. In Mode 1, the satellite is facing a fixed point on the ground, which is not the nadir point. Calculate the satellite's field of view for the ground and the visibility of ground targets.

[0006] Furthermore, in mode 0, when the satellite half-beam angle Less than the auxiliary angle At that time, that is Calculate the satellite's field of view to the Earth. The auxiliary angle is the half-beam angle when the satellite's field of view at the nadir point is tangent to the Earth. Specifically, it includes: (2.1) Calculate the initial point; (2-1) (2-2) in, It is the distance from the starting point to the sphere below the star. This represents the Earth's average radius. Indicates the latitude, longitude, and altitude of the satellite's nadir point. The numbers 0, 1, and 2 in the brackets above represent latitude, longitude, and altitude, respectively. (2.2) Rotate from the initial point to find the remaining points of the elliptical boundary of the field of view, specifically including: Let the vector to be rotated be (2-3) in, This represents the vector pointing from the satellite to the initial point in the J2000 coordinate system. This represents the satellite's spatial position vector in the J2000 coordinate system. This represents the starting point vector in the J2000 coordinate system; The unit vector of the rotation axis is calculated as follows: (2-4) in, This represents the unit vector representing the satellite's spatial position in the J2000 coordinate system. Calculate the rotation angle for: (2-5) in, Indicates the number of rotations. Indicates the number of boundary points of the ground region; Calculate the transition matrix for: (2-6) Calculate the rotation matrix for: (2-7) in, Indicates the rotation angle; Rotated vector (2-8) Boundary point spatial position vector : (2-9) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

[0007] Furthermore, in mode 0, when the satellite half-beam angle Greater than or equal to the auxiliary angle At that time, that is Calculate the satellite's field of view for Earth, specifically including: (2.1) Calculate the initial point (2-10) (2-11) (2.2) Rotate from the initial point to find the remaining points of the elliptical boundary of the field of view, specifically including: Let the vector to be rotated be: (2-12) The unit vector of the rotation axis is calculated as follows: (2-13) The rotation angle is calculated as follows: (2-14) Calculate the transition matrix for: (2-15) The rotation matrix R is calculated as follows: (2-16) Calculate the rotated vector: (2-17) Spatial position vector of boundary point: (2-18) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

[0008] Furthermore, in mode 0, the visibility of ground targets is calculated, specifically including: The latitude, longitude and altitude of the input ground station The spatial position vector of the ground station in the J2000 coordinate system was obtained after coordinate transformation. : (2-19) (2-20) (2-21) (2-22) in, This is the satellite-to-ground station vector in the J2000 coordinate system. The angle between the satellite's pointing vector to the ground station and the satellite's spatial position vector; To assist in the included angle, The distance from the ground station to the satellite. This is the vector pointing from the ground station to the satellite in the J2000 coordinate system; when hour; (2-23) in, This indicates that distance is determined based on criterion 1; if If so, the ground station is considered visible; if If so, the ground station is considered invisible; when hour, (2-24) like If so, the ground station is considered visible; if If so, the ground station is considered invisible.

[0009] Furthermore, in Mode 1, the angle between the pointing point, the satellite, and the nadir point is calculated. Determine whether the satellite's Earth-view coverage area is calculated using either Method 1 or Method 2. (2-25) in, This represents the vector pointing from the satellite to the target point in the J2000 coordinate system. when In this case, use method one; when Then, use method two.

[0010] Furthermore, in method one, calculating the satellite's Earth field of view coverage specifically includes: (3.1) Calculate the initial point (2-26) (2-27) (3.2) Rotate from the initial point to find the remaining points, specifically including: Let the vector to be rotated (2-28) Calculate the unit vector of the rotation axis (2-29) Calculate the rotation angle (2-30) Calculate the transition matrix N: (2-31) Rotation matrix R (2-32) Calculate the rotated vector (2-33) Calculate the spatial position vector of the boundary point (2-34) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

[0011] Furthermore, in Method 2, the calculation of the satellite's Earth field of view coverage specifically includes: (3.1) Calculate the initial point like ; Let the vector to be rotated be (2-35) Calculate the unit vector of the rotation axis: (2-36) in, Let J2000 be the rotation axis vector. The spatial position vector pointing to the point in the J2000 coordinate system; The unit vector of the rotation axis in the J2000 coordinate system; Calculate the rotation angle : (2-37) Calculate the transition matrix N: (2-38) Calculate the rotation matrix R: (2-39) Calculate the rotated vector: (2-40) Calculate the spatial position vector of the boundary point: (2-41) in, The starting point vector in the J2000 coordinate system; The spatial position vector of the boundary point The latitude, longitude, and altitude of the corresponding starting point are obtained through coordinate transformation. ; like ; Let the vector to be rotated be (2-42) Calculate the unit vector of the rotation axis: (2-43) Calculate the rotation angle: (2-44) Calculate the transition matrix: (2-45) Calculate the rotation matrix (2-46) Calculate the rotated vector (2-47) Calculate the spatial position vector of the boundary point (2-48) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. ; (3.2) Rotate from the initial point to find the remaining points, specifically including: Let the vector to be rotated be (2-49) Calculate the unit vector of the rotation axis as (2-50) in, It is the unit vector obtained by normalizing the rotation axis vector. This is the vector pointing from the satellite to the pointing point in the J2000 coordinate system; Calculate the rotation angle (2-51) Calculate the transition matrix N: (2-52) Calculate the rotation matrix R: (2-53) Calculate the rotated vector: (2-54) Solve the equation (2-55) in, The coefficient that makes the vector obtained after rotating the satellite pointing to the initial point vector fall on the Earth's surface; If equation (2-55) has a solution, then (2-56) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. ; If equation (2-55) has no solution, then (2-57) (2-58) (2-59) (2-60) (2-61) in, The vector is the satellite vector projected onto the plane. The coefficients of the vector projected from the satellite to the pointing point onto the plane; The coefficients of the vector projected onto the plane after rotating the satellite's initial point vector; The vector projected onto the plane from the satellite's vector to the pointing point; The vector between the point where the satellite-to-point vector lands on the plane and the point where the rotation vector lands on the plane; Solve the equation (2-62) (2-63) in, The coefficient that compresses the vector between the points where the rotation vector lands on the plane to the Earth's surface; The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. .

[0012] Furthermore, in Mode 1, the visibility of ground targets is calculated as follows: The latitude, longitude and altitude of the input ground station The spatial position vector of the ground station in the J2000 coordinate system was obtained after coordinate transformation. ; (2-64) (2-65) (2-66) in, This is the satellite-to-ground station vector in the J2000 coordinate system. The angle between the ground station, the satellite, and the pointing point. The distance from the ground station to the satellite. This is the vector pointing from the ground station to the satellite in the J2000 coordinate system; Judgment 1: If

[0013] (2-67) in, Distance judgment criterion 1; (a) If

[0014] (2-68) Criterion 2 for distance judgment; If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. (b) If

[0015] (2-69) Judgment 2: If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. like and , (2-70) (a) If

[0016] (2-71) If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. (b) If

[0017] (2-72) If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. Judgment 3: If

[0018] (2-73) If satisfied If the ground station is visible, it will be visible; otherwise, it will not be visible.

[0019] The advantages of this invention compared to the prior art are: Existing methods for calculating satellite field of view only consider the scenario where the satellite is directly facing the Earth, and are ineffective when the satellite is pointing towards a specific ground point. Furthermore, existing methods are very cumbersome and time-consuming in determining the visibility of ground stations. The method proposed in this invention solves the problem of calculating the satellite field of view when the satellite is pointing towards a specific ground point; simultaneously, the proposed method greatly simplifies the visibility calculation process and reduces computation time. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of Mode 0 of the present invention; Figure 3 This is a schematic diagram of Mode 1 of the present invention; Figure 4 This is a diagram comparing it with STK. Detailed Implementation

[0021] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0022] Assume there is a reconnaissance (communication) satellite in space with a known half-angle; multiple ground stations with known latitude and longitude; and a beam pointing point with known latitude and longitude. The goal is to calculate the satellite's field of view and determine whether the ground stations are visible. To address this scenario, this invention provides a method for calculating the satellite's field of view coverage and the visibility of ground targets, such as... Figure 1 As shown, it includes the following steps: Step 1: Divide the satellite field of view into two types: mode 0 and mode 1. Mode 0 refers to the nadir mode, and mode 1 refers to the fixed point mode pointing to a certain ground point. Step 2: In Mode 0, with the satellite facing the nadir point, calculate the satellite's field of view for the Earth and the visibility of ground targets; Step 3: In Mode 1, the satellite is facing a fixed point on the ground, which is not the nadir point. Calculate the satellite's field of view and the visibility of ground targets.

[0023] The symbol definitions designed in this invention are shown in Table 1 below: Table 1 Symbol Definition Table

[0024] Mode 0 (Near-Satellite Point Mode): Calculates the satellite's field of view and ground target visibility when the satellite is directly facing the nadir point, such as... Figure 2 As shown.

[0025] Satellite field of view calculation 1) If

[0026] Calculate the initial point (2-1) (2-2) Find the remaining points by rotating from the initial point: Vector to be rotated (2-3) Rotation axis unit vector (2-4) Rotation angle (2-5) Calculate the transition matrix: (2-6) Calculate the rotation matrix (2-7) Rotated vector (2-8) Boundary point spatial position vector (2-9) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0027] 2) If

[0028] Calculate the initial point (2-10) (2-11) Find the remaining points by rotating from the initial point: Vector to be rotated (2-12) Rotation axis unit vector (2-13) Rotation angle (2-14) Transition matrix: (2-15) Rotation matrix (2-16) Rotated vector (2-17) Boundary point spatial position vector (2-18) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0029] Ground station visibility calculation: From the input After coordinate transformation, we obtain : (2-19) (2-20) (2-21) (2-22) 1) If

[0030] (2-23) like If so, the ground station is considered visible; like If so, the ground station is considered invisible; 2) If

[0031] (2-24) like If so, the ground station is considered visible; like If so, the ground station is considered invisible.

[0032] Mode 1 (Pointing to a fixed ground point (not nadir point) mode): Calculates the satellite's field of view and ground target visibility when the satellite is directly facing a fixed ground point (not nadir point), such as... Figure 3 As shown.

[0033] Satellite field of view calculation: (2-25) 1) If

[0034] Find the initial point (2-26) (2-27) Find the remaining points by rotating from the initial point: Vector to be rotated (2-28) Rotation axis unit vector (2-29) Rotation angle (2-30) Transition matrix: (2-31) Rotation matrix (2-32) Rotated vector (2-33) Boundary point spatial position vector (2-34) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0035] 2) If

[0036] Find the initial point (a) If

[0037] Vector to be rotated (2-35) Rotation axis unit vector (2-36) Rotation angle (2-37) Transition matrix: (2-38) Rotation matrix (2-39) Rotated vector (2-40) Boundary point spatial position vector (2-41) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0038] (b) If

[0039] Vector to be rotated (2-42) Rotation axis unit vector (2-43) Rotation angle (2-44) Transition matrix: (2-45) Rotation matrix (2-46) Rotated vector (2-47) Boundary point spatial position vector (2-48) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0040] Find the remaining points by rotating from the initial point: Vector to be rotated (2-49) Rotation axis unit vector (2-50) Rotation angle (2-51) Transition matrix: (2-52) Rotation matrix (2-53) Rotated vector (2-54) Solve the equation (2-55) (1) If equation (2-55) has a solution (2-56) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0041] (2) If equation (2-55) has no solution (2-57) (2-58) (2-59) (2-60) (2-61) Solve the equation (2-62) (2-63) The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. .

[0042] Ground station visibility calculation: From the input After coordinate transformation, we obtain

[0043] (2-64) (2-65) (2-66) Judgment 1: If

[0044] (2-67) (a) If

[0045] (2-68) If satisfied and If the conditions are not met, the ground station will be visible; otherwise... and Then the ground station is not visible. (b) If

[0046] (2-69) If satisfied and If the conditions are not met, the ground station will be visible; otherwise... and If so, the ground station will not be visible.

[0047] Judgment 2: If and

[0048] (2-70) (a) If

[0049] (2-71) If satisfied and If yes, the ground station will be visible; otherwise, the requirement is not met. and If so, the ground station will not be visible.

[0050] (b) If

[0051] (2-72) If satisfied and If the conditions are not met, the ground station will be visible; otherwise... and If so, the ground station will not be visible.

[0052] Judgment 3: If

[0053] (2-73) If satisfied If the conditions are not met, the ground station will be visible; otherwise... If so, the ground station will not be visible.

[0054] Example: The simulation parameters are set as shown in Table 2 below.

[0055] Table 2 Simulation Parameter Settings

[0056] The simulation results are shown in Tables 3 and 4.

[0057] Table 3 Ground Visibility Results

[0058] Table 4 Results of ground field of view boundary points

[0059] Several points were selected and compared with the STK calculation results, as follows: Figure 4 As shown in the figure, several points from the table are selected. It can be seen that the selected points fall precisely on the satellite's field of view coverage generated by the STK software. It can also be seen that ground station 1 is not within the field of view, while ground station 2 is within the field of view, which verifies the correctness of the algorithm.

[0060] The parts of this invention not described in detail are common knowledge to those skilled in the art.

Claims

1. A method for calculating the coverage range of a satellite's field of view and the visibility of ground targets, characterized in that, include: The satellite field of view is divided into two modes: mode 0 and mode 1. Mode 0 refers to the nadir mode, while mode 1 refers to the mode pointing to a fixed point on the ground. In Mode 0, the satellite is directly facing the nadir point, and the satellite's field of view and the visibility of ground targets are calculated. In Mode 1, the satellite is facing a fixed point on the ground, which is not the nadir point. Calculate the satellite's field of view for the ground and the visibility of ground targets.

2. The method for calculating the satellite's field of view coverage and the visibility of ground targets according to claim 1, characterized in that: In mode 0, when the satellite half-beam angle Less than the auxiliary angle At that time, that is Calculate the satellite's field of view to the Earth. The auxiliary angle is the half-beam angle when the satellite's field of view at the nadir point is tangent to the Earth. Specifically, it includes: (2.1) Calculate the initial point; （2-1） （2-2） in, It is the distance from the starting point to the sphere below the star. This represents the Earth's average radius. Indicates the latitude, longitude, and altitude of the satellite's nadir point. The numbers 0, 1, and 2 in the brackets above represent latitude, longitude, and altitude, respectively. (2.2) Rotate from the initial point to find the remaining points of the elliptical boundary of the field of view, specifically including: Let the vector to be rotated be （2-3） in, This represents the vector pointing from the satellite to the initial point in the J2000 coordinate system. This represents the satellite's spatial position vector in the J2000 coordinate system. This represents the starting point vector in the J2000 coordinate system; The unit vector of the rotation axis is calculated as follows: （2-4） in, This represents the unit vector representing the satellite's spatial position in the J2000 coordinate system. Calculate the rotation angle for: （2-5） in, Indicates the number of rotations. Indicates the number of boundary points of the ground region; Calculate the transition matrix for: （2-6） Calculate the rotation matrix for: （2-7） in, Indicates the rotation angle; Rotated vector (2-8) Boundary point spatial position vector : (2-9) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

3. The method for calculating the satellite's field of view coverage and the visibility of ground targets according to claim 2, characterized in that: In mode 0, when the satellite half-beam angle Greater than or equal to the auxiliary angle At that time, that is Calculate the satellite's field of view for Earth, specifically including: (2.1) Calculate the initial point （2-10） （2-11） (2.2) Rotate from the initial point to find the remaining points of the elliptical boundary of the field of view, specifically including: Let the vector to be rotated be: (2-12) The unit vector of the rotation axis is calculated as follows: (2-13) The rotation angle is calculated as follows: (2-14) Calculate the transition matrix for: （2-15） The rotation matrix R is calculated as follows: （2-16） Calculate the rotated vector: (2-17) Spatial position vector of boundary point: (2-18) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

4. A method for calculating the coverage range of a satellite's field of view and the visibility of ground targets according to claim 2 or 3, characterized in that: Calculating ground target visibility in Mode 0 includes: The latitude, longitude and altitude of the input ground station The spatial position vector of the ground station in the J2000 coordinate system was obtained after coordinate transformation. : （2-19） （2-20） （2-21） （2-22） in, This is the satellite-to-ground station vector in the J2000 coordinate system. The angle between the satellite's pointing vector to the ground station and the satellite's spatial position vector; To assist in the included angle, The distance from the ground station to the satellite. This is the vector pointing from the ground station to the satellite in the J2000 coordinate system; when hour; （2-23） in, This indicates that distance is determined based on criterion 1; if If so, the ground station is considered visible; if If so, the ground station is considered invisible; when hour, （2-24） like If so, the ground station is considered visible; if If so, the ground station is considered invisible.

5. The method for calculating the satellite's field of view coverage and the visibility of ground targets according to claim 2, characterized in that: In Mode 1, the angle between the pointing point, the satellite, and the nadir point is calculated. Determine whether the satellite's Earth-view coverage area is calculated using either Method 1 or Method 2. (2-25) in, This represents the vector pointing from the satellite to the target point in the J2000 coordinate system. when In this case, use method one; when Then, use method two.

6. The method for calculating the satellite's field of view coverage and the visibility of ground targets according to claim 5, characterized in that: In Method 1, the calculation of the satellite's Earth field of view coverage specifically includes: (3.1) Calculate the initial point （2-26） （2-27） (3.2) Rotate from the initial point to find the remaining points, specifically including: Let the vector to be rotated （2-28） Calculate the unit vector of the rotation axis （2-29） Calculate the rotation angle （2-30） Calculate the transition matrix N: （2-31） Rotation matrix R （2-32） Calculate the rotated vector （2-33） Calculate the spatial position vector of the boundary point （2-34） The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. This means obtaining the remaining points of the elliptical boundary of the field of view range obtained by rotating from the initial point.

7. The method for calculating the satellite's field of view coverage and the visibility of ground targets according to claim 5, characterized in that: In Method 2, the calculation of the satellite's Earth field of view coverage specifically includes: (3.1) Calculate the initial point like ; Let the vector to be rotated be (2-35) Calculate the unit vector of the rotation axis: (2-36) in, Let J2000 be the rotation axis vector. The spatial position vector pointing to the point in the J2000 coordinate system; The unit vector of the rotation axis in the J2000 coordinate system; Calculate the rotation angle : （2-37） Calculate the transition matrix N: （2-38） Calculate the rotation matrix R: （2-39） Calculate the rotated vector: （2-40） Calculate the spatial position vector of the boundary point: （2-41） in, The starting point vector in the J2000 coordinate system; The spatial position vector of the boundary point The latitude, longitude, and altitude of the corresponding starting point are obtained through coordinate transformation. ; like ; Let the vector to be rotated be (2-42) Calculate the unit vector of the rotation axis: (2-43) Calculate the rotation angle: （2-44） Calculate the transition matrix: （2-45） Calculate the rotation matrix （2-46） Calculate the rotated vector （2-47） Calculate the spatial position vector of the boundary point （2-48） The spatial position vector of the boundary point is transformed by coordinates to obtain the corresponding latitude, longitude, and altitude. ; (3.2) Rotate from the initial point to find the remaining points, specifically including: Let the vector to be rotated be （2-49） Calculate the unit vector of the rotation axis as （2-50） in, It is the unit vector obtained by normalizing the rotation axis vector. This is the vector pointing from the satellite to the pointing point in the J2000 coordinate system; Calculate the rotation angle （2-51） Calculate the transition matrix N: （2-52） Calculate the rotation matrix R: （2-53） Calculate the rotated vector: （2-54） Solve the equation (2-55) in, The coefficient that makes the vector obtained after rotating the satellite pointing to the initial point vector fall on the Earth's surface; If equation (2-55) has a solution, then (2-56) The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. ; If equation (2-55) has no solution, then (2-57) （2-58） （2-59） （2-60） （2-61） in, The vector is the satellite vector projected onto the plane. The coefficients of the vector projected from the satellite to the pointing point onto the plane; The coefficients of the vector projected onto the plane after rotating the satellite's initial point vector; The vector projected onto the plane from the satellite's vector to the pointing point; The vector between the point where the satellite-to-point vector lands on the plane and the point where the rotation vector lands on the plane; Solve the equation （2-62） （2-63） in, The coefficient that compresses the vector between the points where the rotation vector lands on the plane to the Earth's surface; The spatial position vector of the boundary point The corresponding latitude, longitude, and altitude are obtained through coordinate transformation. .

8. A method for calculating the coverage range of a satellite's field of view and the visibility of ground targets according to claim 6 or 7, characterized in that: In Mode 1, the visibility of ground targets is calculated as follows: The latitude, longitude and altitude of the input ground station The spatial position vector of the ground station in the J2000 coordinate system was obtained after coordinate transformation. ; （2-64） （2-65） （2-66） in, This is the satellite-to-ground station vector in the J2000 coordinate system. The angle between the ground station, the satellite, and the pointing point. The distance from the ground station to the satellite. This is the vector pointing from the ground station to the satellite in the J2000 coordinate system; Judgment 1: If （2-67） in, Distance judgment criterion 1; (a) If (2-68) Criterion 2 for distance judgment; If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. (b) If （2-69） Judgment 2: If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. like and , （2-70） (a) If （2-71） If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. (b) If （2-72） If satisfied and If so, the ground station is visible; otherwise, the ground station is not visible. Judgment 3: If （2-73） If satisfied If the ground station is visible, it will be visible; otherwise, it will not be visible.

Images