Onboard multi-strip stitching computation method and system

Abstract

The application provides a kind of on-orbit multi-strip splicing calculation method and system, comprising: orbit recursion is carried out and is converted into position, velocity vector under satellite inertial system;Calculate the unit pointing vector of satellite to the specified center point vector under the orbit system;Adjacent strip center point distance is calculated;Calculate the azimuth of direction point, adjacent strip center point relative to the specified center point;Adjacent strip center point position, direction point position are calculated.The application solves the problem of multi-strip splicing calculation of high-resolution narrow-width wide observation satellite single-pass large-area imaging, can effectively calculate the latitude and longitude of the center point and azimuth point of each strip in multi-strip splicing, realize satellite single-pass multi-strip splicing large-scale imaging, and ensure the observation ability of satellite single-pass to large area.

Description

Technical Field

[0001] This invention relates to the field of satellite single-track large-area multi-strip stitching imaging, specifically to a satellite multi-strip stitching calculation method and system. Background Technology

[0002] Modern Earth observation satellites have increasingly higher resolutions, but they cannot simultaneously achieve wide swaths. To achieve imaging of a large area in a single satellite pass, it is necessary to stitch multiple strips together. Traditional observation satellites usually use ground-based commands to stitch multiple strips together. With the rapid increase in the number of satellites in orbit, this has put a lot of pressure on ground application systems. Onboard autonomous mission planning is an important way to alleviate this pressure. The multi-strip stitching algorithm is an important part of autonomous mission planning. By calculating the coordinates of the center point and direction point of each strip using the multi-strip stitching algorithm, onboard autonomous mission planning for stitching multiple strips over a large area in a single satellite pass can be achieved, minimizing the workload of ground application systems during long-term management.

[0003] Patent document CN110111260A discloses a method for planning a formation satellite strip stitching imaging task, comprising: determining the observation target area based on the boundary points of the regional target; obtaining the flight trajectory of each satellite within a set observation task time from the velocity and position information of each satellite in the formation satellites, and obtaining the minimum side swing angle required for the boundary points of the observation target area to be observed and the corresponding observation time; planning the observation target area into multiple observation strips in a set order, and determining the observation satellites corresponding to each observation strip from the formation satellites; calculating the intersection point position and corresponding observation time of the inner and outer boundary curves of each observation strip with the boundary of the observation target area based on the side swing angle corresponding to the boundary of each observation strip, and determining the observation duration corresponding to each observation strip; and calculating the latitude and longitude of the observation point of each observation satellite based on the velocity and position information and side swing angle of each observation satellite at the observation time.

[0004] However, patent document CN110111260A cannot solve the technical problem of how to calculate the position of the center point and direction point of each strip in the calculation of multi-strip splicing in a single satellite passing over the periphery. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for calculating multi-strip splicing on satellite.

[0006] A method for calculating the splicing of multiple satellite stripes according to the present invention includes:

[0007] Step S110: Perform orbit recursion and convert it into position and velocity vectors in the satellite's inertial frame;

[0008] Step S120: Based on the position and velocity vectors in the satellite's inertial frame, calculate the unit pointing vector of the satellite's vector to the specified center point in the orbital frame;

[0009] Step S130: Calculate the distance between the center points of adjacent strips based on the unit pointing vector under the orbital system;

[0010] Step S140: Calculate the direction point and the azimuth angle of the adjacent strip center points relative to the specified center point based on the distance between the center points of the adjacent strips;

[0011] Step S150: Calculate the position of the center point and the position of the direction point of the adjacent strips based on the azimuth angle of the center point of the adjacent strips relative to the specified center point.

[0012] Preferably, step S110 includes:

[0013] Step S111: Calculate the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips;

[0014] Step S112: Based on the time from the current moment to the time of the satellite observation of the designated center point, the orbital elements at the time of the satellite observation of the designated center point are recursively obtained from the orbital elements at the current moment, and the orbital elements at that moment are converted from six elements into position and velocity vectors in the satellite's inertial frame.

[0015] The system employs autonomous mission planning for multi-strip stitching in a single satellite pass over a single area. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent, making it a multi-strip stitching system with push-broom direction constraints. Attitude maneuvers only exist between different strip imaging processes, and the attitude is fixed during each strip push-broom process.

[0016] Preferably, step S120 includes:

[0017] Step S121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system based on the latitude, longitude and altitude information of the specified center point;

[0018] Step S122: Calculate the position vector of the specified center point in the inertial frame using the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point; wherein, the transformation matrix from the inertial frame to the Earth-fixed frame is as follows:

[0019] M ECI2ECF =EP·ER·NR·PR

[0020] Where EP is the polar motion matrix, ER is the Earth's rotation matrix, NR is the nutation matrix, and PR is the precession matrix, we get M. ECI2ECFThe inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame.

[0021] Step S123: Based on the position vector of the specified center point in the inertial frame, obtain the pointing vector of the satellite to the specified center point through vector operation. Combined with the position and velocity vectors of the satellite in the inertial frame, calculate the pointing vector in the orbital frame. Then, obtain the unit pointing vector in the orbital frame at the time when the satellite observes the specified center point by normalization.

[0022] Coordinate transformation matrix M from the orbital frame to the J2000 inertial frame orb2ECI as follows:

[0023]

[0024] In the formula Y a =(V sECI ×R sECI ), X a =R sECI ×Y a V sECI Let R be the velocity vector of the satellite in the inertial frame. sECI This is the satellite's position vector in the inertial frame.

[0025] Preferably, in step S130:

[0026] Based on the unit pointing vector in the orbital system at the specified time of satellite observation of the specified center point, calculate the roll angle of the specified center point relative to the orbital coordinate system, and combine it with the half angle of the satellite payload swath width to calculate the distance between the center points of adjacent strips;

[0027] Step S140 includes:

[0028] Step S141: Based on the latitude and longitude information of the specified center point and direction point, calculate the azimuth angle of the direction point relative to the specified center point; wherein, based on the latitude and longitude of the specified center point A and direction point B, a third point C is set to construct a spherical right triangle, the longitude of point C is the longitude of the specified center point, and the latitude is the latitude of the direction point, and the dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points A, B, and C are all known, angles a, b, and c are calculated by converting latitude and longitude to position vectors, where angle a is ∠BOC, angle b is ∠AOC, and angle c is ∠AOB; the dihedral angle ∠BAC is obtained as the azimuth angle of the direction point relative to the specified center point using the following spherical triangle formula:

[0029] sin(a)=sin(c)sin(∠BAC)

[0030] Step S142: Calculate the azimuth angle of the adjacent strip center points relative to the specified center point based on the azimuth angle of the direction point relative to the specified center point and the distance between the adjacent strip center points.

[0031] Preferably, step S150 includes:

[0032] Step S151: Calculate the latitude and longitude of the adjacent strip center points based on the latitude and longitude of the specified center point, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point, and use these as the positions of the adjacent strip center points.

[0033] Step S152: Calculate the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point, and use these as the positions of the adjacent strip direction points.

[0034] A satellite-based multi-strip splicing computing system according to the present invention includes:

[0035] Module M110: Performs orbit recursion and converts it into position and velocity vectors in the satellite's inertial frame;

[0036] Module M120: Calculates the unit pointing vector of the satellite's vector to the specified center point in the orbital system based on the satellite's position and velocity vectors in the satellite's inertial frame;

[0037] Module M130: Calculates the distance between the center points of adjacent strips based on the unit pointing vector under the orbital system;

[0038] Module M140: Calculates the direction point and the azimuth angle of the adjacent strip center points relative to the specified center point based on the distance between the center points of the adjacent strips;

[0039] Module M150: Calculates the position of the center point and the direction point of the adjacent strips based on the azimuth angle of the center point of the adjacent strips relative to the specified center point.

[0040] Preferably, the module M110 includes:

[0041] Module M111: Calculates the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips;

[0042] Module M112: Based on the time from the current moment to the time of the satellite observation at the designated center point, the orbital elements at the current moment are recursively derived to obtain the orbital elements at the time of the satellite observation at the designated center point, and the orbital elements at that moment are converted from six elements into position and velocity vectors in the satellite's inertial frame.

[0043] The system employs autonomous mission planning for multi-strip stitching in a single satellite pass over a single area. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent, making it a multi-strip stitching system with push-broom direction constraints. Attitude maneuvers only exist between different strip imaging processes, and the attitude is fixed during each strip push-broom process.

[0044] Preferably, the module M120 includes:

[0045] Module M121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system based on the latitude, longitude and altitude information of the specified center point;

[0046] Module M122: Calculates the position vector of the specified center point in the inertial frame from the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point; wherein, the transformation matrix from the inertial frame to the Earth-fixed frame is as follows:

[0047] M ECI2ECF =EP·ER·NR·PR

[0048] Where EP is the polar motion matrix, ER is the Earth's rotation matrix, NR is the nutation matrix, and PR is the precession matrix, we get M. ECI2ECF The inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame.

[0049] Module M123: Based on the position vector of the specified center point in the inertial frame, the pointing vector of the satellite to the specified center point is obtained through vector operation. Combined with the position and velocity vectors of the satellite in the inertial frame, the pointing vector in the orbital frame is calculated. The unit pointing vector in the orbital frame at the time when the satellite observes the specified center point is obtained through normalization.

[0050] Coordinate transformation matrix M from the orbital frame to the J2000 inertial frame orb2ECI as follows:

[0051]

[0052] In the formula Y a =(V sECI ×R sECI ), X a =R sECI ×Y a V sECI Let R be the velocity vector of the satellite in the inertial frame. sECI This is the satellite's position vector in the inertial frame.

[0053] Preferably, in module M130:

[0054] Based on the unit pointing vector in the orbital system at the specified time of satellite observation of the specified center point, calculate the roll angle of the specified center point relative to the orbital coordinate system, and combine it with the half angle of the satellite payload swath width to calculate the distance between the center points of adjacent strips;

[0055] The module M140 includes:

[0056] Module M141: Based on the latitude and longitude information of a specified center point and direction point, calculate the azimuth angle of a direction point relative to a specified center point. Specifically, based on the latitude and longitude of the specified center point A and direction point B, a third point C is set to construct a spherical right triangle. The longitude of point C is the longitude of the specified center point, and the latitude is the latitude of the direction point. The dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points A, B, and C are all known, angles a, b, and c are calculated by converting latitude and longitude to position vectors. Angle a is ∠BOC, angle b is ∠AOC, and angle c is ∠AOB. The dihedral angle ∠BAC is obtained using the following spherical triangle formula, representing the azimuth angle of the direction point relative to the specified center point.

[0057] sin(a)=sin(c)sin(∠BAC)

[0058] Module M142: Calculates the azimuth angle of the adjacent strip center points relative to the specified center point based on the azimuth angle of the direction point relative to the specified center point and the distance between the adjacent strip center points.

[0059] Preferably, the module M150 includes:

[0060] Module M151: Calculates the latitude and longitude of the adjacent strip center points based on the specified center point's latitude and longitude, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point, and uses this as the position of the adjacent strip center points;

[0061] Module M152: Calculates the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point, and uses this as the position of the adjacent strip direction points.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. This invention solves the problem of multi-strip stitching calculation for large-area imaging during a single transit of a high-resolution, narrow-swath, wide-range observation satellite. It can effectively calculate the latitude and longitude of the center point and azimuth point of each strip in the multi-strip stitching, realize large-area imaging of multi-strip stitching during a single satellite transit, and is suitable for autonomous mission planning of multi-strip stitching in on-board areas, ensuring the satellite's ability to observe large areas during a single transit.

[0064] 2. This invention is designed for multi-strip stitching imaging applications in the area surrounding a specified observation center point. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent. It is a multi-strip stitching algorithm with strip push-broom direction constraints rather than being limited to the track direction. By cleverly using spherical triangles to calculate the latitude and longitude of the center point and direction point of each strip, the solution requires less computational resources and is easy to implement on satellite.

[0065] 3. The present invention provides a multi-strip stitching calculation method with a given center point and direction point. By calculating the latitude and longitude of the center point and direction point of each strip, multi-strip stitching in a fixed direction is achieved. Specifically, multiple strips in the same direction are stitched together. Attitude maneuvering only exists between different strip imaging processes, and the attitude is fixed during each strip push-broom process. Attached Figure Description

[0066] 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:

[0067] Figure 1 This is a schematic diagram of the process steps of the on-board multi-strip splicing calculation method of the present invention.

[0068] Figure 2 This is a schematic diagram illustrating the principle of constructing a spherical right-angled triangle from a specified center point and direction point. Detailed Implementation

[0069] 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.

[0070] As the performance of satellite-borne computers becomes increasingly advanced, satellite mission planning is gradually shifting from ground systems to autonomous onboard operations. Onboard autonomous mission planning enables satellites to autonomously schedule missions in orbit, complete observation tasks, and transmit data down, eliminating a series of complex tasks such as mission planning, command uploading, and data downloading on the ground system. This greatly improves satellite efficiency and reduces the pressure on ground application systems.

[0071] Onboard autonomous mission planning consists of a series of planning algorithms. For Earth observation satellites, especially high-resolution satellites, the payload swath is generally narrow. When the satellite passes through the mission area, push-broom imaging acquires a single narrow-band image, which cannot obtain a large-scale image of the mission area in a single pass. Therefore, it is necessary to solve the problem of large-scale imaging of high-resolution narrow-swath satellites in a single pass by by stitching multiple bands.

[0072] To address the problem of large-area imaging during a single transit of a high-resolution, narrow-swath, wide-viewing satellite, this invention proposes an on-board multi-strip stitching calculation method. Using this invention, the problem of on-board multi-strip stitching calculation can be effectively solved, enabling large-area imaging through multi-strip stitching during a single satellite transit.

[0073] Figure 1 This is a schematic diagram of the process steps of a multi-strip splicing calculation method for satellites provided by the present invention, as shown below. Figure 1 As shown in the embodiment, the on-board multi-strip splicing calculation method includes:

[0074] Step S110: Perform trajectory recursion and convert it into position and velocity in an inertial frame; Step S110 includes:

[0075] Step S111: Calculate the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips;

[0076] Step S112: The orbital elements at the specified center point of the satellite observation are obtained by recursively calculating the orbital elements at the current time, and the orbital elements at that time are converted from six elements into position and velocity in the inertial frame.

[0077] Step S120: Calculate the unit pointing vector of the satellite to the designated center point in the orbital frame; calculate the position of the designated center point in the Earth-fixed system based on the latitude, longitude, and altitude information of the designated center point; calculate the position vector of the designated center point in the inertial frame based on the time of satellite observation of the designated center point; calculate the pointing vector of the satellite to the designated center point in the inertial frame based on the position vector of the satellite in the inertial frame; then obtain the pointing vector in the orbital frame through the conversion from the inertial frame to the orbital frame; finally, obtain the unit pointing vector in the orbital frame through normalization. Step S120 includes:

[0078] Step S121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system;

[0079] Step S122: Calculate the position vector of the specified center point in the inertial frame from the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point;

[0080] The transformation matrix from the inertial frame to the Earth-fixed frame is as follows:

[0081] M ECI2ECF =EP·ER·NR·PR

[0082] Where EP is the polar motion matrix, ER is the Earth's rotation matrix, NR is the nutation matrix, and PR is the precession matrix, we get M. ECI2ECF The inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame.

[0083] Step S123: Obtain the pointing vector of the satellite to the specified center point through vector operation, calculate the pointing vector in the orbital system by combining the position and velocity vectors in the satellite's inertial frame, and obtain the unit pointing vector in the orbital system by normalization.

[0084] Coordinate transformation matrix M from the orbital frame to the J2000 inertial frame orb2ECI as follows:

[0085]

[0086] In the formula Y a =(V sECI ×R sECI ), X a =R sECI ×Y a V sECI Let R be the velocity vector of the satellite in the inertial frame. sECI This is the satellite's position vector in the inertial frame.

[0087] Step S130: Calculate the distance between the center points of adjacent strips

[0088] Based on the unit pointing vector in the orbital system at the specified center point time obtained from step S120, calculate the roll angle of the specified center point relative to the orbital coordinate system, and calculate the distance between the center points of adjacent strips by combining the half angle of the satellite payload swath width.

[0089] Step S140: Calculate the azimuth angle of the direction point and the center point of the adjacent strip relative to the specified center point; Step S140 includes:

[0090] Step S141: Based on the latitude and longitude information of the specified center point and direction point, and combined with the relevant calculation formulas for spherical triangles, calculate the azimuth angle of the direction point relative to the specified center point; for example... Figure 2 Based on the latitude and longitude of the specified center point A and direction point B, a third point C is set (longitude of the specified center point and latitude of the direction point) to construct a spherical right triangle. The dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points are known, angles a (∠BOC), b (∠AOC), and c (∠AOB) are calculated by converting latitude and longitude to position vectors. The dihedral angle ∠BAC is obtained by using the following spherical triangle formula. It is the azimuth angle of the direction point relative to the specified center point. The quadrant of the azimuth angle should be considered during the calculation.

[0091] sin(a)=sin(c)sin(∠BAC)

[0092] Step S142: Calculate the azimuth angle of the center point of the adjacent strip relative to the specified center point.

[0093] Step S150: Calculate the center point and direction point positions of adjacent strips; Step S150 includes:

[0094] Step S151: Calculate the latitude and longitude of the adjacent strip center points based on the latitude and longitude of the specified center point, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point.

[0095] Step S152: Calculate the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point.

[0096] This invention also provides an on-board multi-strip stitching calculation system, which can be implemented by those skilled in the art through executing the steps of the on-board multi-strip stitching calculation method. That is, the on-board multi-strip stitching calculation method can be understood as a preferred embodiment of the on-board multi-strip stitching calculation system. Specifically, the on-board multi-strip stitching calculation system includes:

[0097] Module M110: Performs orbit recursion and converts it into position and velocity vectors in the satellite's inertial frame;

[0098] Module M120: Calculates the unit pointing vector of the satellite's vector to the specified center point in the orbital system based on the satellite's position and velocity vectors in the satellite's inertial frame;

[0099] Module M130: Calculates the distance between the center points of adjacent strips based on the unit pointing vector under the orbital system;

[0100] Module M140: Calculates the direction point and the azimuth angle of the adjacent strip center points relative to the specified center point based on the distance between the center points of the adjacent strips;

[0101] Module M150: Calculates the position of the center point and the direction point of the adjacent strips based on the azimuth angle of the center point of the adjacent strips relative to the specified center point.

[0102] The module M110 includes:

[0103] Module M111: Calculates the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips;

[0104] Module M112: Based on the time from the current moment to the time of the satellite observation at the designated center point, the orbital elements at the current moment are recursively derived to obtain the orbital elements at the time of the satellite observation at the designated center point, and the orbital elements at that moment are converted from six elements into position and velocity vectors in the satellite's inertial frame.

[0105] The system employs autonomous mission planning for multi-strip stitching in a single satellite pass over a single area. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent, making it a multi-strip stitching system with push-broom direction constraints. Attitude maneuvers only exist between different strip imaging processes, and the attitude is fixed during each strip push-broom process.

[0106] The module M120 includes:

[0107] Module M121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system based on the latitude, longitude and altitude information of the specified center point;

[0108] Module M122: Calculates the position vector of the specified center point in the inertial frame from the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point; wherein, the transformation matrix from the inertial frame to the Earth-fixed frame is as follows:

[0109] M ECI2ECF =EP·ER·NR·PR

[0110] Where EP is the polar motion matrix, ER is the Earth's rotation matrix, NR is the nutation matrix, and PR is the precession matrix, we get M. ECI2ECF The inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame.

[0111] Module M123: Based on the position vector of the specified center point in the inertial frame, the pointing vector of the satellite to the specified center point is obtained through vector operation. Combined with the position and velocity vectors of the satellite in the inertial frame, the pointing vector in the orbital frame is calculated. The unit pointing vector in the orbital frame at the time when the satellite observes the specified center point is obtained through normalization.

[0112] Coordinate transformation matrix M from the orbital frame to the J2000 inertial frame orb2ECI as follows:

[0113]

[0114] In the formula Y a =(V sECI ×R sECI ), X a =R sECI ×Y a V sECI Let R be the velocity vector of the satellite in the inertial frame. sECI This is the satellite's position vector in the inertial frame.

[0115] In module M130:

[0116] Based on the unit pointing vector in the orbital system at the specified time of satellite observation of the specified center point, calculate the roll angle of the specified center point relative to the orbital coordinate system, and combine it with the half angle of the satellite payload swath width to calculate the distance between the center points of adjacent strips;

[0117] The module M140 includes:

[0118] Module M141: Based on the latitude and longitude information of a specified center point and direction point, calculate the azimuth angle of a direction point relative to a specified center point. Specifically, based on the latitude and longitude of the specified center point A and direction point B, a third point C is set to construct a spherical right triangle. The longitude of point C is the longitude of the specified center point, and the latitude is the latitude of the direction point. The dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points A, B, and C are all known, angles a, b, and c are calculated by converting latitude and longitude to position vectors. Angle a is ∠BOC, angle b is ∠AOC, and angle c is ∠AOB. The dihedral angle ∠BAC is obtained using the following spherical triangle formula, representing the azimuth angle of the direction point relative to the specified center point.

[0119] sin(a)=sin(c)sin(∠BAC)

[0120] Module M142: Calculates the azimuth angle of the adjacent strip center points relative to the specified center point based on the azimuth angle of the direction point relative to the specified center point and the distance between the adjacent strip center points.

[0121] The module M150 includes:

[0122] Module M151: Calculates the latitude and longitude of the adjacent strip center points based on the specified center point's latitude and longitude, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point, and uses this as the position of the adjacent strip center points;

[0123] Module M152: Calculates the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point, and uses this as the position of the adjacent strip direction points.

[0124] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0125] 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 calculating the splicing of multiple on-board bands, characterized in that, include: Step S110: Perform orbit recursion and convert it into position and velocity vectors in the satellite's inertial frame; Step S120: Based on the position and velocity vectors in the satellite's inertial frame, calculate the unit pointing vector of the satellite's vector to the specified center point in the orbital frame; Step S130: Calculate the distance between the center points of adjacent strips based on the unit pointing vector under the orbital system; Step S140: Calculate the direction point and the azimuth angle of the adjacent strip center points relative to the specified center point based on the distance between the center points of the adjacent strips; Step S150: Calculate the position of the center point and the position of the direction point of the adjacent strips based on the azimuth angle of the center point of the adjacent strips relative to the specified center point; In step S130: Based on the unit pointing vector in the orbital system at the specified time of satellite observation of the specified center point, calculate the roll angle of the specified center point relative to the orbital coordinate system, and combine it with the half angle of the satellite payload swath width to calculate the distance between the center points of adjacent strips; Step S140 includes: Step S141: Based on the latitude and longitude information of the specified center point and direction point, calculate the azimuth angle of the direction point relative to the specified center point; wherein, based on the latitude and longitude of the specified center point A and direction point B, a third point C is set to construct a spherical right triangle, the longitude of point C is the longitude of the specified center point, and the latitude is the latitude of the direction point, and the dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points A, B, and C are all known, the angle is calculated by converting latitude and longitude to position vector. Angles b and c, where angle c is the most significant. That is, ∠BOC, angle b is ∠AOC, and angle c is ∠AOB; the dihedral angle ∠BAC is obtained by using the following formula for spherical triangles, which gives the azimuth angle of the direction point relative to the specified center point: Step S142: Calculate the azimuth angle of the adjacent strip center points relative to the specified center point based on the azimuth angle of the direction point relative to the specified center point and the distance between the adjacent strip center points.

2. The on-board multi-strip splicing calculation method according to claim 1, characterized in that, Step S110 includes: Step S111: Calculate the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips; Step S112: Based on the time from the current moment to the time of the satellite observation of the designated center point, the orbital elements at the time of the satellite observation of the designated center point are recursively obtained from the orbital elements at the current moment, and the orbital elements at that moment are converted from six elements into position and velocity vectors in the satellite's inertial frame. The system employs autonomous mission planning for multi-strip stitching in a single satellite pass over a single area. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent, making it a multi-strip stitching system with push-broom direction constraints. Attitude maneuvers only exist between different strip imaging processes, and the attitude is fixed during each strip push-broom process.

3. The on-board multi-strip splicing calculation method according to claim 2, characterized in that, Step S120 includes: Step S121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system based on the latitude, longitude and altitude information of the specified center point; Step S122: Calculate the position vector of the specified center point in the inertial frame using the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point; wherein, the transformation matrix from the inertial frame to the Earth-fixed frame is as follows: in It is a polar shift matrix. This is the Earth's rotation matrix. For nutation matrix, Given the precession matrix, we obtain... The inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame. Step S123: Based on the position vector of the specified center point in the inertial frame, obtain the pointing vector of the satellite to the specified center point through vector operation. Combined with the position and velocity vectors of the satellite in the inertial frame, calculate the pointing vector in the orbital frame. Then, obtain the unit pointing vector in the orbital frame at the time when the satellite observes the specified center point by normalization. Coordinate transformation matrix from orbital frame to J2000 inertial frame as follows: In the formula , , Let V be the velocity vector of the satellite in the inertial frame. This is the satellite's position vector in the inertial frame.

4. The on-board multi-strip splicing calculation method according to claim 3, characterized in that, Step S150 includes: Step S151: Calculate the latitude and longitude of the adjacent strip center points based on the latitude and longitude of the specified center point, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point, and use these as the positions of the adjacent strip center points. Step S152: Calculate the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point, and use these as the positions of the adjacent strip direction points.

5. A satellite-based multi-strip splicing computing system, characterized in that, include: Module M110: Performs orbit recursion and converts it into position and velocity vectors in the satellite's inertial frame; Module M120: Calculates the unit pointing vector of the satellite's vector to the specified center point in the orbital system based on the satellite's position and velocity vectors in the satellite's inertial frame; Module M130: Calculates the distance between the center points of adjacent strips based on the unit pointing vector under the orbital system; Module M140: Calculates the direction point and the azimuth angle of the adjacent strip center points relative to the specified center point based on the distance between the center points of the adjacent strips; Module M150: Calculates the position of the center point and the position of the direction point of the adjacent strips based on the azimuth angle of the center point of the adjacent strips relative to the specified center point; In module M130: Based on the unit pointing vector in the orbital system at the specified time of satellite observation of the specified center point, calculate the roll angle of the specified center point relative to the orbital coordinate system, and combine it with the half angle of the satellite payload swath width to calculate the distance between the center points of adjacent strips; The module M140 includes: Module M141: Based on the latitude and longitude information of a specified center point and direction point, calculate the azimuth angle of a direction point relative to a specified center point. Specifically, based on the latitude and longitude of the specified center point A and direction point B, a third point C is set to construct a spherical right triangle. The longitude of point C is the longitude of the specified center point, and the latitude is the latitude of the direction point. The dihedral angle ∠ACB is a right angle. Since the latitude and longitude of the three points A, B, and C are all known, the angle is calculated by converting latitude and longitude to a position vector. Angles b and c, where angle c is the most significant. That is, ∠BOC, angle b is ∠AOC, and angle c is ∠AOB; the dihedral angle ∠BAC is obtained by using the following formula for spherical triangles, which gives the azimuth angle of the direction point relative to the specified center point: Module M142: Calculates the azimuth angle of the adjacent strip center points relative to the specified center point based on the azimuth angle of the direction point relative to the specified center point and the distance between the adjacent strip center points.

6. The on-board multi-strip splicing computing system according to claim 5, characterized in that, The module M110 includes: Module M111: Calculates the time from the current moment to the time of the satellite observation at the designated center point based on the pre-imaging preparation time, the number of imaging strips, the single-strip imaging time, and the attitude maneuvering time between strips; Module M112: Based on the time from the current moment to the time of the satellite observation at the designated center point, the orbital elements at the current moment are recursively derived to obtain the orbital elements at the time of the satellite observation at the designated center point, and the orbital elements at that moment are converted from six elements into position and velocity vectors in the satellite's inertial frame. The system employs autonomous mission planning for multi-strip stitching in a single satellite pass over a single area. The push-broom direction is determined by the center point and the direction point. The push-broom direction of multiple strips is consistent, making it a multi-strip stitching system with push-broom direction constraints. Attitude maneuvers only exist between different strip imaging processes, and the attitude is fixed during each strip push-broom process.

7. The on-board multi-strip splicing computing system according to claim 6, characterized in that, The module M120 includes: Module M121: Considering the Earth ellipsoid model, calculate the position vector of the specified center point in the Earth-fixed system based on the latitude, longitude and altitude information of the specified center point; Module M122: Calculates the position vector of the specified center point in the inertial frame from the position vector of the specified center point in the Earth-fixed frame and the time of satellite observation of the specified center point; wherein, the transformation matrix from the inertial frame to the Earth-fixed frame is as follows: in It is a polar shift matrix. This is the Earth's rotation matrix. For nutation matrix, Given the precession matrix, we obtain... The inverse of the matrix is ​​the transformation matrix from the Earth-fixed frame to the inertial frame. Module M123: Based on the position vector of the specified center point in the inertial frame, the pointing vector of the satellite to the specified center point is obtained through vector operation. Combined with the position and velocity vectors of the satellite in the inertial frame, the pointing vector in the orbital frame is calculated. The unit pointing vector in the orbital frame at the time when the satellite observes the specified center point is obtained through normalization. Coordinate transformation matrix from orbital frame to J2000 inertial frame as follows: In the formula , , Let V be the velocity vector of the satellite in the inertial frame. This is the satellite's position vector in the inertial frame.

8. The on-board multi-strip splicing computing system according to claim 5, characterized in that, The module M150 includes: Module M151: Calculates the latitude and longitude of the adjacent strip center points based on the specified center point's latitude and longitude, the distance between the specified center point and the adjacent strip center points, and the azimuth angle of the adjacent strip center points relative to the specified center point, and uses this as the position of the adjacent strip center points; Module M152: Calculates the latitude and longitude of the adjacent strip direction points based on the latitude and longitude of the adjacent strip center points, the distance between the specified center point and the azimuth point, and the azimuth angle of the direction point relative to the specified center point, and uses this as the position of the adjacent strip direction points.

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