Satellite attitude and sailboard combined guidance method and system based on double-turntable decomposition

Abstract

The application provides a satellite attitude and sailboard combined guidance method and system based on double-turntable decomposition. The method comprises the following steps: establishing a satellite body coordinate system and a sailboard coordinate system, the first axis of the satellite body coordinate system points to the direction that needs to be kept in the satellite task, and the second axis points to the SADA rotation axis direction; the satellite body is defined as a one-dimensional turntable rotating around the first axis, and the SADA is defined as a one-dimensional turntable rotating around the second axis; taking the initial time satellite body coordinate system coinciding with the orbit coordinate system as the reference, a rotation matrix chain from the orbit coordinate system to the sailboard coordinate system is constructed; the sailboard normal vector is transformed to the orbit coordinate system based on the inverse transformation of the rotation matrix chain, and an equation constraint that the sailboard normal vector is equal to the sun vector in the orbit coordinate system is established; according to the equation constraint, the azimuth angle and the pitch angle θ are synchronously solved, which are respectively taken as the expected yaw angle of the satellite body and the expected driving angle of the SADA.

Description

Technical Field

[0001] This application mainly relates to the fields of satellite attitude control and solar panel drive technology, and in particular to a satellite attitude and solar panel joint guidance method, system and storage medium based on dual turntable decomposition. Background Technology

[0002] With the widespread application of flat-panel satellites in low-Earth orbit communication, remote sensing, and other fields, satellite platforms are required to simultaneously meet the dual mission requirements of payload pointing towards the Earth and solar panel tracking. Flat-panel satellites typically mount payloads such as communication antennas and remote sensing cameras on the +Z plane of the satellite body, requiring the payload mounting surface to continuously point towards the Earth's center during satellite operation; at the same time, the solar panels deploy along the ±Y plane of the satellite body, requiring a SADA (Solar Array Drive Assembly) to drive the panels to rotate and track the sun, ensuring the overall power supply of the satellite.

[0003] To simultaneously meet the dual mission requirements mentioned above, existing technologies typically employ the following solutions: One solution involves installing a two-dimensional SADA (Satellite Adaptor Controller) on the satellite. The satellite platform maintains stable orientation relative to the Earth along three axes, and the two rotating axes of the two-dimensional SADA control the azimuth and pitch motion of the solar panels, achieving solar tracking. However, this solution suffers from drawbacks such as high complexity of the drive hardware and software, increased failure risk due to the increased number of rotating mechanisms, and significant hardware weight and cost. Another solution combines yaw maneuvers with a single-degree-of-freedom SADA to drive the satellite and solar panels. The yaw maneuver capability of the satellite platform, combined with the single-degree-of-freedom SADA, enables solar tracking, reducing the amount of hardware required. However, in these solutions, the calculation of the platform yaw angle and the SADA drive angle is often performed in isolated steps, relying on factors such as the right ascension of the ascending node, orbital inclination, and the accumulated angle calculation of orbital time integration. This often involves too many integral judgments and conditions, making it susceptible to cumulative drift due to initial value errors. This results in limited guidance accuracy and complex calculations, increasing unreliability in engineering applications and making it difficult to meet the requirements of high-precision payload Earth tracking missions and SADA-driven solar energy acquisition.

[0004] Therefore, there is an urgent need for a high-precision closed-loop guidance method that combines satellite attitude and solar panels with a simple and reliable algorithm. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a satellite attitude and solar panel joint guidance method, system and storage medium based on dual turntable decomposition, so as to solve the problem of low guidance accuracy of existing methods.

[0006] To address the aforementioned technical problems, this application provides a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition, comprising: Establish a satellite body coordinate system and a solar panel coordinate system. The first axis of the satellite body coordinate system points to the direction in which the satellite needs to maintain its attitude during the mission, and the second axis points to the direction of the SADA rotation axis. The first axis and the second axis are orthogonal. When the SADA is at zero position, the three axes of the solar panel coordinate system are consistent with those of the satellite body coordinate system. The satellite body is defined as a one-dimensional turntable rotating about the first axis, and the SADA is defined as a one-dimensional turntable rotating about the second axis. Based on the initial coincidence of the satellite body coordinate system and the orbit coordinate system, a rotation matrix chain is constructed from the orbit coordinate system to the solar panel coordinate system. The rotation matrix chain sequentially includes: rotating the azimuth angle around the direction corresponding to the first axis in the orbit coordinate system. Then rotate the pitch angle θ around the direction corresponding to the second axis in the rotated coordinate system; Based on the inverse transformation of the rotation matrix chain, the solar panel normal vector is transformed to the orbital coordinate system, and an equality constraint is established to make the solar panel normal vector equal to the solar vector in the orbital coordinate system. Based on the aforementioned equality constraints, the azimuth angle can be solved analytically and synchronously. The pitch angle θ is used as the desired yaw angle of the satellite body and the desired drive angle of the SADA, respectively.

[0007] In some embodiments, the first axis is the Z-axis, the second axis is the Y-axis, the load mounting surface is located on the +Z plane of the satellite system, the solar panels are mounted along the ±Y plane, and the rotation axis of the SADA is along the Y-axis direction.

[0008] In some embodiments, the rotation matrix chain from the orbital coordinate system to the sail coordinate system is:

[0009] in, For the rotation matrix chain, The azimuth angle of rotation around the Z-axis of the orbital coordinate system The rotation matrix, Let be the rotation matrix for the pitch angle θ of the rotated coordinate system about the Y-axis.

[0010] In some embodiments, the method for transforming the solar panel normal vector to the orbital coordinate system is as follows:

[0011] in, The normal vector of the sail in the orbital coordinate system. This is the inverse transformation of the rotation matrix chain. Let SADA be the normal vector of the windsurfing system in the windsurfing coordinate system. When SADA is at zero position, .

[0012] In some embodiments, the equality constraint is:

[0013] in, is the solar vector in the orbital coordinate system.

[0014] In some embodiments, the azimuth angle and the pitch angle The parsing expression is:

[0015] in, It is the arctangent function in the fourth quadrant. It is an inverse cosine function.

[0016] In some embodiments, the method further includes: calculating the orbital plane solar angle. ;when When the azimuth angle exceeds a preset threshold, the joint guidance mode is executed: the satellite body yaws around the first axis by the specified azimuth angle. SADA rotates the pitch angle about the second axis. ;when When the value is less than or equal to the preset threshold, the satellite enters a degraded guidance mode: the satellite body maintains a three-axis Earth-oriented orientation, and the desired attitude is... SADA rotates only around the second axis to track the solar vector.

[0017] In some embodiments, under the degradation guidance mode, the SADA angle calculation formula is:

[0018] The solar vector in the orbital coordinate system is represented as: .

[0019] In some embodiments, the orbital solar angle is calculated using the following formula. :

[0020] The solar vector in the orbital coordinate system is represented as: .

[0021] In some embodiments, the preset threshold is 20°.

[0022] In some embodiments, the first axis is the X-axis, the second axis is the Y-axis, the satellite's propulsion system is installed on the +X or -X plane of the satellite body, the solar panels are installed along the ±Y plane, and the rotation axis of the SADA is along the Y-axis direction.

[0023] In some embodiments, the rotation matrix chain from the orbital coordinate system to the sail coordinate system is:

[0024] in, For the rotation matrix chain, The azimuth angle of rotation around the X-axis of the orbital coordinate system The rotation matrix, Let be the rotation matrix for the pitch angle θ of the rotated coordinate system about the Y-axis.

[0025] To address the aforementioned technical problems, this application provides a satellite attitude and solar panel joint guidance system based on dual-turntable decomposition, comprising: a processor and a memory, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in this application.

[0026] To address the aforementioned technical problems, this application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method described in this application.

[0027] Compared with the prior art, this application has the following advantages: This application presents a satellite attitude and solar panel joint guidance method, system, and storage medium based on dual-turntable decomposition. It establishes a dual-turntable decomposition model with "azimuth axis and pitch axis" by defining the satellite body as a one-dimensional turntable rotating around a first axis and the SADA as a one-dimensional turntable rotating around a second axis. Based on this, a complete rotation matrix chain from the orbital coordinate system to the solar panel coordinate system is constructed. Through the inverse transformation of the rotation matrix chain, the solar panel normal vector is transformed to the orbital coordinate system, and an equality constraint equal to the solar vector is established. Based on this equality constraint, the azimuth angle γ and pitch angle θ are simultaneously and analytically solved, serving as the desired yaw angle of the satellite body and the desired drive angle of the SADA, respectively. The above process does not involve time integration; it is entirely based on the real-time solar vector at the current moment for instantaneous analytical solution, eliminating accumulated drift errors and achieving high-precision closed-loop guidance in a strictly defined sense. Compared to the open-loop uniform-speed drive method in existing technologies that relies on time integration to accumulate angles, this application significantly improves the solar panel's solar pointing accuracy, meeting the attitude pointing requirements of high-precision payload missions. Attached Figure Description

[0028] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0029] Figure 1 This is a flowchart of a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition according to an embodiment of this application.

[0030] Figure 2 This is a schematic diagram of the satellite body coordinate system and the solar panel coordinate system according to an embodiment of this application.

[0031] Figure 3 This is a schematic diagram of the solar vector in the orbital coordinate system according to an embodiment of this application.

[0032] Figure 4 This is a schematic diagram of the angle calculation of SADA in the degradation guidance mode according to an embodiment of this application.

[0033] Figure 5 This is a schematic diagram of the expected yaw angle change of a satellite body according to an embodiment of this application.

[0034] Figure 6 This is a schematic diagram of the expected angle change of SADA according to an embodiment of this application.

[0035] Figure 7 This is a schematic diagram showing the change of the angle between the solar vector and the direction of the solar panel normal in the orbital coordinate system according to an embodiment of this application.

[0036] Figure 8 This is an embodiment of the track surface of this application. A diagram comparing the angle, the angle between the sail and the solar vector.

[0037] Figure 9 This is a schematic diagram showing the changes in the yaw angle and SADA drive angle of a satellite body according to an embodiment of this application.

[0038] Figure 10 This is a schematic diagram of a satellite attitude and solar panel joint guidance system based on dual-turntable decomposition according to an embodiment of this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0040] This application provides a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition. For example... Figure 1 As shown, the satellite attitude and solar panel joint guidance method 100 based on dual-turntable decomposition includes the following steps: Step S101: Establish the satellite body coordinate system and the solar panel coordinate system.

[0041] The satellite's body coordinate system is defined as follows: the first axis points to the direction in which the satellite's attitude needs to be maintained during the mission, and the second axis points to the direction of the SADA rotation axis. The first axis and the second axis are orthogonal. The direction in which the satellite's attitude needs to be maintained during the mission is defined differently in different scenarios. In conventional Earth-tracking missions, the first axis points to the direction normal to the payload mounting surface (+Z plane) for Earth-tracking (+Z axis direction). This method can simultaneously solve the solar panel tracking problem during the satellite payload's Earth-tracking guidance and the satellite's main payload's Earth-tracking orientation process. In orbital maneuvering missions, when the satellite's propulsion system is installed on the +X or -X plane of the satellite's body coordinate system, and the solar panels are installed along the ±Y plane, the first axis is the X-axis, and the second axis is the Y-axis, to ensure solar panel tracking during propulsion.

[0042] The definition of the solar panel coordinate system is as follows: when the SADA is at zero position, the three axes of the solar panel coordinate system are aligned with those of the satellite body coordinate system.

[0043] In this embodiment, as Figure 2 As shown, the origin of the satellite's body coordinate system OXsYsZs is located at the satellite's center of mass. The Zs axis points towards the load mounting surface (i.e., the +Z plane, relative to the ground), and the Ys axis points towards the solar panel deployment direction (i.e., the ±Y direction). The Xs axis, Zs axis, and Ys axis form a right-handed coordinate system. This coordinate system is fixed to the satellite body and moves with the satellite's attitude, used to describe the satellite platform's attitude orientation in space.

[0044] The solar panel coordinate system OLxLyLz is defined as follows: When SADA is at zero position, the three axes of the solar panel coordinate system and the satellite body coordinate system are aligned, that is, the Lx, Ly, and Lz axes of the solar panel coordinate system are parallel and in the same direction as the Xs, Ys, and Zs axes of the satellite body coordinate system. The solar panel coordinate system is fixed to the solar panel and rotates relative to the satellite body coordinate system as SADA rotates, used to describe the orientation of the solar panel in space. When SADA is at zero position, the solar panel normal vector is represented in the solar panel coordinate system as follows: .

[0045] Figure 2 In the satellite's +Y and The coordinate systems OLxLyLz for the solar panels are labeled on both sides of the Y-axis because the flat-panel satellite has a set of solar panels installed in both the ±Y directions, and a set of SADA (Satellite Adaptor Control) on each side. The two sets of solar panels and SADA are mechanically symmetrically installed, but share the same coordinate system definition. That is, when the SADA is at zero position, the coordinate systems of both solar panels are aligned with the three axes of the satellite's body coordinate system, and both SADAs rotate around the same rotation axis (Y-axis). Therefore, the two labels in the figure represent a repetition of the same solar panel coordinate system definition at two symmetrical positions. In kinematic modeling, both solar panels share the same set of coordinate transformations and the same set of guidance laws, and the desired drive angle of the SADA is the same.

[0046] Combination Figure 2 It is known that the following geometric constraint exists between the satellite body coordinate system and the solar panel coordinate system: the normal direction of the load mounting surface (+Zs direction) is orthogonal to the SADA rotation axis direction (±Ys direction). This orthogonality provides the geometric basis for the construction of the rotation matrix chain in this application. When the SADA rotates around the Y-axis, the solar panel normal moves in the XZ plane, changing the direction of the solar panel normal to track the change in the projection of the solar vector onto the XZ plane of the orbital system; when the satellite body yaws around the Z-axis, the projection direction of the solar panel normal onto the XY plane of the orbital system changes. Together, these three constitute the geometric basis for the two-degree-of-freedom joint control of "satellite body yaw (around Z) and SADA rotation (around Y)".

[0047] Step S102: Define the satellite body as a one-dimensional turntable rotating around the first axis, and define SADA as a one-dimensional turntable rotating around the second axis.

[0048] In this embodiment, the first axis is the Zs axis, and the second axis is the Ys axis. The satellite body is defined as a one-dimensional turntable (azimuth axis turntable) rotating around Zs, and the SADA is defined as a one-dimensional turntable (pitch axis turntable) rotating around Ys. The satellite body and SADA constitute a series two-axis linkage system, where the satellite body provides the azimuth degree of freedom, and the SADA provides the pitch degree of freedom.

[0049] Step S103: Based on the initial moment when the satellite body coordinate system coincides with the orbit coordinate system, construct a rotation matrix chain from the orbit coordinate system to the solar panel coordinate system.

[0050] In this step, the satellite body coordinate system and the orbit coordinate system coincide at the initial moment as the reference attitude, and a complete rotation matrix chain from the orbit coordinate system to the solar panel coordinate system is constructed.

[0051] like Figure 3 As shown, let the orbital coordinate system be... XoYoZo The solar vector below is When SADA is at zero position, the normal vector of the windsurfing plate is represented in the windsurfing plate coordinate system as: .

[0052] According to the "dual turntable decomposition" model defined in this application, in this embodiment, the satellite body is defined as a one-dimensional turntable rotating around Zs, and SADA is defined as a one-dimensional turntable rotating around Ys. Therefore, the rotation from the orbital coordinate system to the solar panel coordinate system includes the following steps: Step 1: Rotate the azimuth angle around the Z-axis of the orbital coordinate system The satellite body, based on its Earth-orientation, rotates its azimuth angle around its Z-axis (the direction normal to the payload surface). This step alters the orientation of the windsurfing normal in the orbital coordinate system. XoYoThe projection direction in the plane is equivalent to the yaw maneuver that provides the satellite platform with azimuth freedom. The rotation matrix for rotating the azimuth angle γ around the Z-axis of the orbital coordinate system is:

[0053] Step 2: Rotate the pitch angle θ around the rotated Y-axis. Based on the rotation in Step 1, SADA rotates the pitch angle θ around its own Y-axis (the direction of solar panel deployment, i.e., the satellite's Ys axis). This step changes the solar panel normal in the orbital coordinate system. XoZo The projection direction in the plane is equivalent to the rotation that provides the pitch degree of freedom for SADA. The rotation matrix for rotating the pitch angle θ about the rotated Y-axis is:

[0054] The rotation sequence in this application follows the physical execution order of "azimuth first, then pitch." The satellite platform yaws first, and then SADA rotates relative to the yawed attitude. In matrix operations, transformations are applied to column vectors from right to left. Therefore, the rotation matrix chain from the orbital coordinate system to the solar panel coordinate system is:

[0055] After unfolding, we obtain the complete rotation matrix from the orbital coordinate system to the windsurf coordinate system:

[0056] Step S104: Based on the inverse transformation of the rotation matrix chain, transform the solar panel normal vector to the orbital coordinate system, and establish an equality constraint that the solar panel normal vector is equal to the solar vector in the orbital coordinate system.

[0057] To establish an equality constraint between the solar normal vector and the orbital solar vector, the solar normal vector needs to be transformed from the solar coordinate system to the orbital coordinate system. This transformation requires a rotation matrix. If a matrix is ​​orthogonal, its inverse is equal to its transpose, i.e. Therefore, the rotation matrix from the windsurf coordinate system to the orbit coordinate system is:

[0058] Transform the windsurf normal vector from the windsurf coordinate system to the orbit coordinate system:

[0059] To achieve solar tracking by the solar panel, the solar panel's normal vector must be aligned with the direction of the solar vector in the orbital coordinate system, thus establishing an equality constraint:

[0060] That is:

[0061] Step S105: Based on the equality constraints, simultaneously analyze and solve for the azimuth angle γ and the elevation angle θ, which are respectively used as the desired yaw angle of the satellite body and the desired drive angle of the SADA.

[0062] Based on the above equation constraints, the azimuth angle γ and elevation angle θ can be solved analytically simultaneously by solving the three component equations.

[0063]

[0064] in, This is a four-quadrant arctangent function that can uniquely determine the quadrant of an angle based on the signs of its two independent variables. Its return value ranges from -180° to 180°. ].

[0065] It is an inverse cosine function, and the return value range is [0, 180°].

[0066] Through the complete construction process of the rotation matrix chain described above, a precise mapping from the orbital solar vector to the satellite attitude drive angle is achieved. Compared to the open-loop uniform drive or step-by-step isolated solutions in existing technologies, the rotation matrix chain in this application completes the forward kinematic modeling through a single matrix multiplication, completes the inverse transformation through orthogonal matrix inversion, and finally gives a unique solution in the form of a closed-form analytical expression. The entire derivation process does not involve time integration, so there is no accumulated error, which belongs to a strictly closed-loop analytical solution, providing a mathematical foundation for achieving high-precision solar tracking.

[0067] The above derivation uses a configuration where the first axis is the Z-axis and the second axis is the Y-axis as an example. When the satellite configuration is the first axis is the X-axis (the satellite's propulsion system is installed in the +X or -X plane) and the second axis is the Y-axis, simply change the above derivation... Replace with The rest of the derivation logic is exactly the same, as can be seen in the following examples.

[0068] This embodiment addresses a flat-panel satellite configuration where the satellite's propulsion system is located on the +X or -X plane of the satellite's main body, illustrating the scalability of this application. The first axis of the satellite's main body coordinate system is the X-axis, the second axis is the Y-axis, and the SADA rotation axis is along the Y-axis direction. The difference lies in the rotation matrix chain and analytical expression.

[0069] The rotation matrix chain is:

[0070] in, For the rotation matrix chain, The azimuth angle of rotation around the X-axis of the orbital coordinate system The rotation matrix, Let be the rotation matrix for the pitch angle θ of the rotated coordinate system about the Y-axis.

[0071] After unfolding, we obtain the complete rotation matrix from the orbital coordinate system to the windsurf coordinate system:

[0072] The normal vector of the windshield in the orbital coordinate system is represented as:

[0073] Establish equality constraints:

[0074] Synchronous analytical solution yields:

[0075] This embodiment shows that the core method of this application is not limited to a single configuration. By using an equivalent replacement defined by the rotation axis, it can be adapted to flat-panel satellite configurations with different installation orientations.

[0076] The following embodiments, based on the above embodiments, further introduce a threshold judgment of the orbital plane solar angle β as an optimized control strategy to achieve better control in small... In angular operating conditions, it avoids the risk of drastic changes in yaw guidance attitude angle, leading to large yaw guidance angular velocities or even divergence, while also being in a small... Under angular conditions, the maximum angle between the solar vector and the orbital plane is a preset threshold. Therefore, the satellite can be used for three-axis orientation to the Earth. SADA only needs to track the projection vector of the solar vector in the orbital plane. The guidance rate calculation of both the satellite platform and SADA is relatively simple.

[0077] First, calculate the solar angle on the orbital plane. Sun angle on orbital plane The angle between the solar vector and the orbital plane is calculated using the following formula:

[0078] The solar vector in the orbital coordinate system is represented as: .

[0079] Then, determine The relationship between the value of the preset threshold and the value of the preset threshold is preferred to be 20°. when When the azimuth angle is greater than 20°, the joint guidance mode is executed: the satellite body yaws around the first axis at the specified azimuth angle. SADA rotates the pitch angle about the second axis. The desired attitude of a satellite in its orbital system, described by its Earth-oriented orientation, is: .

[0080] when When the angle is ≤20°, enter the degraded guidance mode: the satellite body maintains three-axis Earth orientation, and the desired attitude is... SADA rotates only around the second axis to track the solar vector.

[0081] like Figure 4 As shown, when When ≤20°, due to The changing trend is quite severe, causing the satellite to have a large yaw angle and angular velocity, which may even exceed the satellite's tracking capabilities in severe cases. Therefore, the satellite is designed to maintain a three-axis Earth-oriented orientation, and the desired attitude in the orbital system is described as follows: The SADA angle calculation formula is:

[0082] The solar vector in the orbital coordinate system is represented as: .

[0083] This embodiment adds a feature outside the joint guidance mode. Corner threshold switching mechanism can be used in small The analytical expression for effectively avoiding the influence of azimuth angle γ under angular conditions is as follows: Occurs at zero crossing The risk of a sharp increase or even divergence in yaw rate caused by a jump from +180° to -180° is mitigated, thus preventing the satellite platform's attitude tracking capability from exceeding its limits and ensuring the safety of overall satellite control. Simultaneously, it maintains its capabilities even in degradation mode. The precise analytical formula drives the SADA single-axis rotation to ensure the sun-pointing accuracy of the sail, while also taking into account energy harvesting efficiency and reducing the design requirements for the yaw channel tracking bandwidth of the attitude control system. This allows this application to cover the entire spectrum from... With an angle range of 0° to ±90° across all operating conditions, it offers enhanced engineering practicality and track adaptability.

[0084] This application presents a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition. It establishes a dual-turntable decomposition model with "azimuth axis and pitch axis" by defining the satellite body as a one-dimensional turntable rotating around a first axis and the SADA as a one-dimensional turntable rotating around a second axis. Based on this, a complete rotation matrix chain from the orbital coordinate system to the solar panel coordinate system is constructed. Through the inverse transformation of the rotation matrix chain, the solar panel normal vector is transformed to the orbital coordinate system, and an equality constraint equal to the solar vector is established. Based on this equality constraint, the azimuth angle γ and pitch angle θ are simultaneously and analytically solved, serving as the desired yaw angle of the satellite body and the desired drive angle of the SADA, respectively. This process does not involve time integration; it is entirely based on the real-time solar vector at the current moment for instantaneous analytical solution, eliminating accumulated drift errors and achieving high-precision closed-loop guidance in a strictly defined sense. Compared to the open-loop uniform-speed drive method in existing technologies that relies on time integration to accumulate angles, this application significantly improves the solar panel's solar pointing accuracy, meeting the attitude pointing requirements of high-precision payload missions. Secondly, this application only requires a single-degree-of-freedom SADA (Satellite Adaptive Control). By utilizing the satellite platform's own yaw maneuverability as its azimuth degree of freedom, and combining it with the pitch degree of freedom of the SADA, it achieves the two-degree-of-freedom motion required for the solar panel normal to track the solar vector in three-dimensional space without introducing a two-dimensional SADA at the hardware level. Compared to existing two-dimensional SADA schemes, this application avoids the hardware and software complexity of dual-axis SADA, reduces the number of rotating mechanisms and critical single-point components, lowers system weight, cost, and on-orbit failure risk, and effectively improves the overall satellite reliability.

[0085] Simulation verification example: To verify the correctness and effectiveness of the joint guidance method proposed in this application, this embodiment uses a low-Earth orbit satellite with an altitude of 495 km and an inclination of 50° for simulation verification. The simulation period covers approximately three orbital years to fully verify the algorithm under different seasons and conditions. Long-term performance under angular operating conditions. During the simulation, the solar vector is calculated in real time based on the astronomical ephemeris, the satellite orbit is extrapolated according to the two-body motion model, and the rotation range of SADA is within the mechanical limits. At the initial moment, the satellite body coordinate system coincides with the orbital coordinate system, that is, the satellite is in the nominal attitude of three-axis Earth orientation.

[0086] Under the above simulation conditions, the curve showing the change of the satellite platform's expected yaw angle (i.e., azimuth angle γ) over time is as follows: Figure 5 As shown. By Figure 5 It can be seen that the expected yaw angle of the satellite platform exhibits a continuous periodic variation within the range of approximately -180° to +180°, with the variation period basically consistent with the orbital period. Simultaneously, it is modulated by the westward retreat of the orbital plane and the seasonal variation of the solar declination, resulting in a slow drift characteristic in the long term. The change in the expected yaw angle is smooth and continuous, without any jumps or abrupt changes, indicating that... Under conditions of >20°, the joint guidance mode can continuously and stably output the platform's desired yaw angle command.

[0087] The curve showing the change of the SADA desired drive angle (i.e., pitch angle θ) over time is as follows: Figure 6 As shown. By Figure 6 It can be seen that the desired SADA drive angle varies periodically within the range of approximately -90° to +90°, synchronized with the orbital period. The range of SADA rotation angle variation is reasonable and does not exceed the mechanical rotation limit range of a typical SADA, indicating that the desired SADA drive angle generated by the joint guidance method of this application meets the engineering feasibility requirements.

[0088] To quantitatively verify the joint guidance accuracy of the present invention, this embodiment defines the normal vector of the sail in the orbital coordinate system. Solar vector in orbital coordinate system The angle between As an evaluation index for the accuracy of sun pointing, among which: From the above analytical expression, it can be seen that if and only if = hour, = 0. Angle between the normal vector of the solar panel and the solar vector. The curve of change over time is as follows Figure 7 As shown.

[0089] Depend on Figure 7 It can be seen that, over the entire simulation timeframe (3 orbital years), the angle between the solar panel normal vector and the orbital system solar vector is... The angle remained consistently near 0°, without any drift or divergence over time. This indicates that the joint guidance method proposed in this application achieves high-precision tracking of the solar panel normal to the sun, verifying the correctness of the technical approach of establishing equality constraints through inverse transformation of the rotation matrix chain and simultaneously analytically solving for the azimuth and pitch angles.

[0090] To verify the claims made in this application Corner threshold switching strategy in small Effectiveness under cornering conditions; this embodiment selects simulation case 1. A specific analysis was conducted on an orbital arc segment with angles varying between 7° and 15°. This arc segment covers the operating range below the 20° switching threshold set in this application, and can fully verify the control effect of the satellite's three-axis Earth orientation plus SADA single-axis drive in the degraded guidance mode.

[0091] Within the selected arc segment, the solar angle on the orbital plane The curve of change and the angle between the normal to the sail and the solar vector. For example, the change curve Figure 8 As shown. Simulation results show that, As the angle gradually decreases from 15° to 7° and then gradually increases back to 15°, the angle between the solar normal and the solar vector... Always with The angles remain equal (i.e.) = The physical implication of this result is that when the satellite maintains its three-axis Earth-oriented orientation without yaw (γ=0°), the pointing of the solar panel normal in the orbital system is controlled by the single-axis drive of SADA, and its solar tracking capability is limited by... The size of the angle itself. When the normal to the solar panel tracks the sun within the orbital plane, it inevitably has a direction perpendicular to the orbital plane due to... The included angle deviation caused by the angle. Therefore, = This represents the optimal theoretical alignment accuracy achievable solely through SADA single-axis drive in the degraded guidance mode. The simulation results of this application are completely consistent with the theoretical optimal value, verifying the correctness of the SADA angle calculation formula in the degraded mode.

[0092] Within the selected arc segment, the curves showing the variation of the satellite platform's yaw angle (γ) and SADA drive angle (θ) are as follows: Figure 9 As shown in the simulation results, under the degraded guidance mode, the desired yaw angle of the satellite platform is always 0°, and the satellite body maintains stable three-axis orientation relative to the ground, avoiding small... There is a risk of divergence in yaw angular velocity. The SADA drive angle rotates continuously and smoothly with the change of the position of the solar vector in the orbital system to track the change of the projection of the solar vector in the XZ plane of the orbital system, ensuring that the solar panel can still obtain optimal solar orientation when the platform is not yawing. The range of change of the SADA drive angle is smooth and without jumps, and the rotational angular velocity is gradual, not exceeding the mechanical rotation and drive capabilities of SADA.

[0093] Based on the results of the two simulation cases above, the following conclusions can be drawn: In joint guidance mode ( At >20°, the angle between the solar normal and the solar vector is always 0°, verifying the correctness and high-precision closed-loop characteristics of the joint guidance method of this application, which establishes equality constraints through inverse transformation of the rotation matrix chain and simultaneously solves the azimuth and pitch angles analytically.

[0094] In the degenerate guidance mode ( At ≤20°, the angle between the normal to the solar panel and the solar vector is equal to This achieves the optimal theoretical accuracy for sun alignment achievable solely through SADA single-axis drive, validating the validity of this application. The correctness of the corner threshold switching strategy and the SADA corner calculation formula under degradation mode.

[0095] The transition between the two modes is smooth, and the angle between the solar panel normal and the solar vector remains continuous before and after the transition without any abrupt changes, verifying the engineering feasibility of the threshold switching strategy proposed in this application. The combination of the two modes achieves... The solar panel tracks the sun within the entire operating range of 0° to ±90°, and the sun-pointing accuracy reaches the theoretical optimal value under the corresponding operating conditions.

[0096] This application also provides a satellite attitude and solar panel joint guidance system based on dual-turntable decomposition. This system can be deployed in an onboard computer, ground simulation equipment, or any general-purpose computer with computing power. Figure 10 As shown, the joint guidance system 1000 includes: a bus 1001, a processor 1002, a memory 1004, and a communication interface 1003. The processor 1002, memory 1004, and communication interface 1003 communicate with each other via the bus 1001. The joint guidance system 1000 can be a server or a terminal device. It should be understood that this application does not limit the number of processors and memories in the joint guidance system 1000.

[0097] Bus 1001 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 10 The bus 1001 may be represented by a single line, but this does not mean that there is only one bus or one type of bus. The bus 1001 may include a path for transmitting information between the various components of the joint guidance system 1000 (e.g., memory 1004, processor 1002, communication interface 1003).

[0098] The processor 1002 may include any one or more processors such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0099] The memory 1004 may include volatile memory, such as random access memory (RAM). The processor 1002 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0100] The memory 1004 stores executable program code, which the processor 1002 executes to implement the aforementioned satellite attitude and solar panel joint guidance method based on dual-turntable decomposition. That is, the memory 1004 stores instructions for executing the satellite attitude and solar panel joint guidance method based on dual-turntable decomposition.

[0101] The communication interface 1003 uses transceiver modules such as, but not limited to, network interface cards and transceivers to enable communication between the joint guidance system 1000 and other devices or communication networks.

[0102] This application also provides a computer program product containing instructions. The computer program product may be software or program products containing instructions, capable of running on a network device or stored on any usable medium. When the computer program product runs on at least one network device, it causes the at least one network device to execute a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition.

[0103] This application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium that a network device can store, or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive). The computer-readable storage medium includes instructions that instruct the network device to execute a satellite attitude and solar panel joint guidance method based on dual-turntable decomposition.

[0104] This application can be widely used in attitude control and solar panel drive systems for various flat-panel satellites, especially suitable for low-Earth orbit communication satellites, remote sensing satellites, and other satellite platforms with high requirements for payload ground pointing and solar panel tracking. This application allows for the simultaneous fulfillment of payload mission requirements and energy supply needs without increasing hardware complexity, demonstrating significant engineering practical value and economic benefits.

[0105] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0106] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

[0108] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A satellite attitude and solar panel joint guidance method based on dual-turntable decomposition, characterized in that, include: Establish a satellite body coordinate system and a solar panel coordinate system. The first axis of the satellite body coordinate system points to the direction in which the satellite needs to maintain its attitude during the mission, and the second axis points to the direction of the SADA rotation axis. The first axis and the second axis are orthogonal. When the SADA is at zero position, the three axes of the solar panel coordinate system are consistent with those of the satellite body coordinate system. The satellite body is defined as a one-dimensional directional turntable rotating around the first axis, and the SADA is defined as a one-dimensional pitch turntable rotating around the second axis. Based on the initial coincidence of the satellite body coordinate system and the orbit coordinate system, a rotation matrix chain is constructed from the orbit coordinate system to the solar panel coordinate system. The rotation matrix chain sequentially includes: rotating the azimuth angle around the direction corresponding to the first axis in the orbit coordinate system. Then rotate the pitch angle θ around the direction corresponding to the second axis in the rotated coordinate system; Based on the inverse transformation of the rotation matrix chain, the solar panel normal vector is transformed to the orbital coordinate system, and an equality constraint is established to make the solar panel normal vector equal to the solar vector in the orbital coordinate system. Based on the aforementioned equality constraints, the azimuth angle can be solved analytically and synchronously. The pitch angle θ is used as the desired yaw angle of the satellite body and the desired drive angle of the SADA, respectively.

2. The method as described in claim 1, characterized in that, The first axis is the Z-axis, the second axis is the Y-axis, the load mounting surface is located on the +Z plane of the satellite system, the solar panels are mounted along the ±Y plane, and the rotation axis of the SADA is along the Y-axis direction.

3. The method as described in claim 2, characterized in that, The rotation matrix chain from the orbital coordinate system to the windsurf coordinate system is as follows: in, For the rotation matrix chain, The azimuth angle of rotation around the Z-axis of the orbital coordinate system The rotation matrix, Let be the rotation matrix for the pitch angle θ of the rotated coordinate system about the Y-axis.

4. The method as described in claim 3, characterized in that, The method for transforming the windsurf normal vector to the orbital coordinate system is as follows: in, The normal vector of the sail in the orbital coordinate system. This is the inverse transformation of the rotation matrix chain. This is the normal vector of the solar panel in the solar panel coordinate system. The normal vector of the solar panel is defined by the installation direction of the solar panels. Here, when SADA is at zero position... .

5. The method as described in claim 4, characterized in that, The equality constraint is: in, is the solar vector in the orbital coordinate system.

6. The method as described in claim 5, characterized in that, The azimuth angle and the pitch angle The parsing expression is: in, It is the arctangent function in the fourth quadrant. It is an inverse cosine function.

7. The method as described in claim 2, characterized in that, Also includes: Calculate the solar angle on the orbital plane ; when When the azimuth angle exceeds a preset threshold, the joint guidance mode is executed: the satellite body yaws around the first axis by the specified azimuth angle. SADA rotates the pitch angle about the second axis. ; when When the value is less than or equal to the preset threshold, the satellite enters a degraded guidance mode: the satellite body maintains a three-axis Earth-oriented orientation, and the desired attitude is... SADA rotates only around the second axis to track the solar vector.

8. The method as described in claim 7, characterized in that, In the degraded guidance mode, the SADA angle calculation formula is as follows: The solar vector in the orbital coordinate system is represented as: .

9. The method as described in claim 7, characterized in that, The orbital solar angle is calculated using the following formula. : The solar vector in the orbital coordinate system is represented as: .

10. The method as described in claim 7, characterized in that, The preset threshold is 20°.

11. The method as described in claim 1, characterized in that, The first axis is the X-axis, the second axis is the Y-axis, the satellite's propulsion system is installed on the +X or -X plane of the satellite body, the solar panels are installed along the ±Y plane, and the rotation axis of the SADA is along the Y-axis direction.

12. The method as described in claim 11, characterized in that, The rotation matrix chain from the orbital coordinate system to the windsurf coordinate system is as follows: in, For the rotation matrix chain, The azimuth angle of rotation around the X-axis of the orbital coordinate system The rotation matrix, Let be the rotation matrix for the pitch angle θ of the rotated coordinate system about the Y-axis.

13. A satellite attitude and solar panel joint guidance system based on dual-turntable decomposition, characterized in that, include: A processor and a memory, the memory storing a computer program, the processor executing the computer program to implement the method as described in any one of claims 1 to 11.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 11.

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