A method for calculating and correcting on-orbit solar angle and satellite-borne software

Abstract

The present invention relates to an on-orbit solar angle calculation and correction method and satellite-borne software, and relates to the field of on-orbit solar capture and two-dimensional rotation mechanism control technology, wherein the method mainly includes the following steps: receiving the satellite attitude and the solar vector in the orbital coordinate system sent by the satellite in real time and judging the correctness of the data; then, according to the correctness of the data, the solar azimuth and pitch angle can be calculated on-orbit by correcting the solar vector or not according to the data injection command; and the positive and negative signs of the calculated solar azimuth and pitch angle can be corrected on-orbit according to the data injection sign parameter, so that the two-dimensional rotation mechanism rotates according to the calculated azimuth and pitch angle of the sun in the guide mirror coordinate system to achieve solar capture. The present invention realizes the calculation and correction of the on-orbit solar angle, ensures that the two-dimensional rotation mechanism of the solar remote sensing instrument can achieve on-orbit solar capture, and avoids the failure of the entire mission caused by the solar remote sensing instrument being unable to capture the sun on-orbit.

Description

Technical Field

[0001] The present invention relates to the technical field of on-orbit solar angle calculation, correction and two-dimensional rotation mechanism control, and in particular to an on-orbit solar angle calculation and correction method and satellite-borne software. Background Art

[0002] A two-dimensional rotation mechanism, carried along with the solar remote sensing instrument, is aboard the satellite platform to perform solar capture and continuous tracking tasks. The guidance mirror, affixed to the mechanism, rotates in response to the mechanism's rotation. The mechanism rotates according to the solar angle (solar azimuth and elevation) calculated by onboard software, capturing the sun within the guidance mirror's field of view (e.g., within a ±0.9° range). The mechanism then uses the sun's offset within the guidance mirror's field of view to perform closed-loop tracking of the sun.

[0003] During the development process, the field of view (FOV) of the guide mirror is often designed to be small (e.g., ±1° × ±1°) in pursuit of high resolution. Furthermore, during satellite launch, vibrations are inevitable, leading to new offsets between the coordinate systems of the various mechanical structures, such as between the 2D rotation mechanism's mounting surface and the satellite's mounting surface, between the 2D rotation mechanism's axis and the mounting surface, and between the 2D rotation mechanism's axis and the guide mirror. Because the onboard software already stores the coordinate system matrix parameters between the 2D rotation mechanism's mechanical structures before launch, these new offsets are likely to result in the 2D rotation mechanism failing to capture the Sun while in orbit.

[0004] The ground-based simulation of an on-orbit solar capture and tracking experiment using a two-dimensional rotating mechanism is complex. The principle is that the light source is fixed in position. When the two-dimensional rotating mechanism is at zero in both azimuth and elevation, the light source is parallel to the optical axis of the guide mirror, simulating the sun. The two-dimensional rotating mechanism is fixed to a hexapod platform, and the hexapod platform's posture changes simulate the motion of an on-orbit solar remote sensing instrument. Factors that affect the accuracy of the sun angle calculation in this process include:

[0005] 1) Satellite data simulation (sun vector, satellite attitude);

[0006] 2) Simulated satellite data processing;

[0007] 3) Simulate satellite data distribution timing constraints;

[0008] 4) Controlling the hexapod platform based on simulated satellite data to simulate the on-orbit motion of solar remote sensing instruments;

[0009] 5) High-precision installation between solar remote sensing instruments and hexapod platforms.

[0010] The above factors determine that ground simulation experiments cannot be completely consistent with the on-orbit conditions. Therefore, the calculation results of the solar angle may contain large errors or mistakes that will not be discovered during the ground simulation experiment, which will lead to the two-dimensional rotation mechanism being unable to capture the sun in orbit.

[0011] Therefore, when there are new offsets between the mechanical structures of the two-dimensional rotation mechanism during the satellite launch process and when the ground experiment cannot be completely consistent with the on-orbit situation, how to ensure the successful on-orbit capture of the two-dimensional rotation mechanism becomes a difficult problem. Summary of the Invention

[0012] In order to solve the above problems, the present invention provides an on-orbit solar angle calculation and correction method and satellite-borne software.

[0013] A method for calculating and correcting the on-orbit solar angle comprises the following steps:

[0014] Step 1: Receive the satellite attitude and the sun vector in the orbital coordinate system sent by the satellite in real time, and determine whether the received data is correct. If so, execute step 2; if not, receive the data again;

[0015] Step 2: Determine whether to correct the sun vector according to the data injection command. If so, execute steps 3 to 7; if not, execute step 8.

[0016] Step 3: Use the installation matrix between the satellite attitude and mechanical structure coordinate systems to correct the sun vector in the orbital coordinate system to the two-dimensional rotation mechanism axis coordinate system;

[0017] Step 4: Determine whether to correct the mechanical structure offset caused by the vibration during satellite launch based on the three-axis rotation angle equivalent correction parameters and correction commands injected by the data. If so, execute step 5; if not, execute step 6.

[0018] Step 5: Use the three-axis rotation angle equivalent correction parameters injected by the data and the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the sun vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system, and then execute step 7;

[0019] Step 6: Use the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the sun vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system;

[0020] Step 7: Calculate the sun angle according to the sun vector in the guide mirror coordinate system, where the sun angle includes the sun azimuth angle and the pitch angle;

[0021] Step 8: Calculate the sun angle based on the sun vector in the orbital coordinate system, and regard the calculated sun angle as the sun angle in the guide mirror coordinate system;

[0022] Step 9: Determine whether the sign of the solar angle is corrected on-orbit. If so, proceed to step 10. If not, terminate the calculation and correction of the solar angle on-orbit.

[0023] Step 10: Correct the sign of the solar angle according to the data injection sign parameter. After correction, the calculation and correction of the on-orbit solar angle are completed.

[0024] On the other hand, the present invention also provides a satellite-borne software running on a solar remote sensing instrument for executing the above-mentioned on-orbit solar angle calculation and correction method.

[0025] Beneficial effects of the invention: The invention provides an on-orbit solar angle calculation and correction method, which is a method for calculating the position and pitch angle of the sun in the guide mirror coordinate system and flexibly correcting the on-orbit solar angle. It solves the problems of huge deviations between mechanical structures caused by vibration during satellite launch or insufficient ground verification of the solar angle calculation method resulting in an error in the sign of the calculated solar angle, which leads to the inability of the instrument to capture the sun. Flexible correction of solar angle calculation is achieved on-orbit through a flexible data injection parameter method, and the method is not limited by the orbital inclination. The two-dimensional rotating mechanism rotates according to the position and pitch angle of the sun in the guide mirror coordinate system calculated by the method to achieve solar capture, which can ensure the successful on-orbit solar capture of the two-dimensional rotating mechanism and avoid the failure of the entire mission caused by the inability of the solar remote sensing instrument to capture the sun on orbit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the satellite's orbit;

[0027] Figure 2 It is the coordinate system diagram of the two-dimensional rotation mechanism;

[0028] Figure 3 This is a flow chart of the on-orbit solar angle calculation and correction method described in the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0030] This embodiment provides a method for calculating and correcting the solar angle on orbit. Figure 3 As shown, the following steps are included:

[0031] Step 1: Receive the satellite attitude and the sun vector in the orbital coordinate system sent by the satellite in real time, and determine whether the received data is correct. If so, execute step 2; if not, receive the data again.

[0032] After the satellite enters orbit, the solar remote sensing instrument is powered on and receives real-time satellite attitude and orbital coordinate system data from the satellite. The sun vector and satellite attitude are the only important inputs for calculating the solar angle. Upon receiving these data, the instrument first verifies their accuracy. If correct, it proceeds to step 2, which determines whether to correct the sun vector. If incorrect, the data is discarded and the satellite attitude and sun vector data are received again.

[0033] Step 2: According to the data injection command: "correct" or "no correction", determine whether to correct the solar vector. If so, execute steps 3 to 7; if not, execute step 8.

[0034] The method of calculating the solar angle by correcting the sun vector using a matrix installed between the satellite's attitude and mechanical coordinate systems is too complex, and ground-based simulations are unlikely to fully replicate on-orbit conditions. Therefore, using the corrected sun vector method to calculate the solar angle is likely to result in errors that go undetected by ground-based experiments. Therefore, the onboard software's on-orbit solar angle calculation function uses the corrected method by default. This can be changed to use or not use the corrected method on-orbit through data injection. The onboard software's selection of the solar angle calculation method through data injection is called the correction function, and this function is independent of the orbital inclination ε. If the data injection command is "correct," the program will jump directly to step three, using the corrected method for calculating the solar angle. If the data injection command is "no correction," the program will jump directly to step eight, using the non-corrected method for calculating the solar angle.

[0035] Step 3: Use the installation matrix between the satellite attitude and mechanical structure coordinate systems to correct the sun vector in the orbital coordinate system to the two-dimensional rotation mechanism axis coordinate system.

[0036] If the data injection determines the method of calculating the solar angle by correcting the solar vector using the satellite attitude and the mounting matrix between the mechanical structure coordinate systems, the onboard software uses the satellite attitude and the mounting matrix between the mechanical structure coordinate systems to correct the solar vector in the orbital coordinate system to the guiding mirror coordinate system. The solar angle in the guiding mirror coordinate system is then calculated based on the solar vector data in the guiding mirror coordinate system. Therefore, in step three, the solar vector in the orbital coordinate system is corrected to the solar vector in the two-dimensional rotating mechanism axis coordinate system based on the satellite attitude, the mounting matrix between the two-dimensional rotating mechanism mounting surface coordinate system (referred to as the mounting coordinate system) and the satellite mounting surface coordinate system (referred to as the satellite coordinate system), and the mounting matrix between the two-dimensional rotating mechanism axis coordinate system and the two-dimensional rotating mechanism mounting surface coordinate system.

[0037] Specifically, step three includes the following steps:

[0038] Step 31: Use the satellite attitude to transform the sun vector in the orbital coordinate system to the satellite coordinate system;

[0039] Step 32: Use the installation matrix between the two-dimensional rotation mechanism installation surface coordinate system and the satellite coordinate system to transform the sun vector in the satellite coordinate system to the two-dimensional rotation mechanism installation surface coordinate system;

[0040] Step 33: Use the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the two-dimensional rotation mechanism installation surface coordinate system to transform the solar vector in the two-dimensional rotation mechanism installation surface coordinate system to the two-dimensional rotation mechanism axis coordinate system.

[0041] Next, the sun vector in the two-dimensional rotation mechanism axis coordinate system needs to be transformed into the guidance mirror coordinate system. During this process, if the correction command decides to use the three-axis rotation angle equivalent correction parameters injected by data to correct the new offset between the mechanical structures of the two-dimensional rotation mechanism during the satellite launch process, then the correction is superimposed when the sun vector is converted from the two-dimensional rotation mechanism axis coordinate system to the guidance mirror coordinate system; if there is no data injection or the correction command decides not to correct the new offset between the mechanical structures of the two-dimensional rotation mechanism during the satellite launch process, then the correction is not superimposed when the sun vector is converted from the two-dimensional rotation mechanism axis coordinate system to the guidance mirror coordinate system. Therefore, in step 4, based on the three-axis rotation angle equivalent correction parameters injected by data and the correction command, it is determined whether to correct the mechanical structure offset caused by vibration during the satellite launch process. If the offset is corrected by data injection, the process jumps to step 5; if the offset is not corrected, the process jumps to step 6. The onboard software does not correct the offset by default.

[0042] Step 5: Use the three-axis rotation angle equivalent correction parameters injected by the data and the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the solar vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system, and then execute step 7.

[0043] Step 6: Use the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the solar vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system.

[0044] Step 7: Calculate the sun angle in the guide mirror coordinate system based on the sun vector in the guide mirror coordinate system, including the sun azimuth angle and pitch angle.

[0045] like Figure 1-Figure 2As shown, the definitions of the orbital coordinate system, satellite coordinate system, two-dimensional rotation mechanism mounting surface coordinate system, two-dimensional rotation mechanism axis coordinate system, and guide mirror coordinate system are overlapping. If in step two, it is determined according to the data injection command that the solar angle is calculated by the method without correcting the solar vector, then jump directly to step eight, that is, calculate the solar angle according to the solar vector in the orbital coordinate system, and the calculated solar angle is regarded as the solar angle in the guide mirror coordinate system.

[0046] Because the solar angle calculation process is complex and the solar angle direction (positive or negative) is manually defined, to avoid errors in the calculated solar angle sign, after the solar angle is calculated, in step nine, a determination is made as to whether the solar angle sign needs to be corrected on-orbit. If the sign of the solar angle is corrected, step ten is executed. If the sign of the solar angle is not corrected, the on-orbit solar angle calculation and correction is terminated, and the onboard software controls the rotation of the two-dimensional rotation mechanism based on the solar angle calculated in step seven or eight to achieve solar acquisition. The onboard software defaults to not correcting the solar angle sign.

[0047] Step 10: Correct the sign of the solar angle according to the data injection sign parameter. After correction, the calculation and correction of the on-orbit solar angle are completed. The onboard software controls the rotation of the two-dimensional rotation mechanism according to the corrected solar angle to achieve solar capture. Figure 3 After the onboard software controls the rotation of the two-dimensional rotation mechanism according to the sun angle to achieve solar capture, return to step one, re-receive the satellite attitude and the solar vector in the orbital coordinate system sent by the satellite in real time, and repeat the above steps one to ten to achieve continuous dynamic capture of the sun by the two-dimensional rotation mechanism of the solar remote sensing instrument.

[0048] This embodiment provides an on-orbit solar angle calculation and correction method, which is a method for calculating the position and pitch angle of the sun in the guide mirror coordinate system and flexibly correcting the on-orbit solar angle. It solves the problems of huge deviations between mechanical structures caused by vibration during satellite launch or insufficient ground verification of the solar angle calculation method resulting in an error in the sign of the calculated solar angle, which makes it impossible for the instrument to capture the sun. Flexible correction of solar angle calculation is achieved on-orbit through a flexible data injection parameter method, and this method is not limited by the orbital inclination. The two-dimensional rotating mechanism rotates according to the position and pitch angle of the sun in the guide mirror coordinate system calculated by this method to achieve solar capture, which can ensure the successful on-orbit solar capture of the two-dimensional rotating mechanism and avoid the failure of the entire mission caused by the failure of the solar remote sensing instrument to capture the sun on orbit.

[0049] The method described in this embodiment mainly includes: 1. Calculating the sun's position and pitch angle in the guidance mirror coordinate system using the real-time received solar vector in the orbital coordinate system and the data-injected solar angle sign correction parameter, i.e., the data-injected sign parameter; 2. Correcting the solar vector in the orbital coordinate system using satellite attitude parameters, the installation matrix between coordinate systems, the data-injected solar angle sign correction parameter, the data-injected three-axis rotation angle equivalent correction parameter, and correction commands to calculate the sun's position and pitch angle in the guidance mirror coordinate system. The onboard software controls the rotation of the two-dimensional rotation mechanism based on the solar azimuth and pitch angle values ​​to achieve solar capture. The onboard software can determine whether to use a correction method or no correction method to calculate the solar azimuth and pitch angle based on the data-injected command: "correct" or "no correction"; the onboard software can correct for new offsets between mechanical structures caused by vibration during satellite launch based on the data-injected three-axis rotation angle equivalent correction parameter and correction command; and the onboard software can correct the signs of the calculated solar azimuth and pitch angle values ​​based on the data-injected sign parameter and command. Under the conditions that there are new offsets between the mechanical structures of the two-dimensional rotation mechanism during the satellite launch process and that the ground experiment cannot be completely consistent with the on-orbit situation, resulting in inaccurate calculation of the solar azimuth and pitch angle, the two-dimensional rotation mechanism can be guaranteed to successfully capture the sun in orbit, avoiding the failure of the entire mission caused by the solar remote sensing instrument being unable to capture the sun in orbit.

[0050] Another embodiment of the present invention further proposes a satellite-borne software that can run on a solar remote sensing instrument. The satellite-borne software is used to execute the above-mentioned on-orbit solar angle calculation and correction method. The specific implementation process of the on-orbit solar angle calculation and correction method can be found in the above-mentioned embodiment and will not be repeated here.

[0051] Furthermore, the onboard software controls the two-dimensional rotation mechanism according to the solar angle calculated in step seven or step eight of the above-mentioned on-orbit solar angle calculation and correction method, or the solar angle corrected in step ten, to achieve solar capture.

[0052] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for calculating and correcting the solar angle on orbit, characterized in that: The following steps are involved: Step 1: Receive the satellite attitude and the sun vector in the orbital coordinate system sent by the satellite in real time, and determine whether the received data is correct. If so, execute step 2; if not, receive the data again; Step 2: Determine whether to correct the sun vector according to the data injection command. If so, execute steps 3 to 7; if not, execute step 8. Step 3: Use the installation matrix between the satellite attitude and mechanical structure coordinate systems to correct the sun vector in the orbital coordinate system to the two-dimensional rotation mechanism axis coordinate system; Step 4: Determine whether to correct the mechanical structure offset caused by the vibration during satellite launch based on the three-axis rotation angle equivalent correction parameters and correction commands injected by the data. If so, execute step 5; if not, execute step 6. Step 5: Use the three-axis rotation angle equivalent correction parameters injected by the data and the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the sun vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system, and then execute step 7; Step 6: Use the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the guide mirror coordinate system to transform the sun vector in the two-dimensional rotation mechanism axis coordinate system to the guide mirror coordinate system; Step 7: Calculate the sun angle according to the sun vector in the guide mirror coordinate system, where the sun angle includes the sun azimuth angle and the pitch angle; Step 8: Calculate the sun angle based on the sun vector in the orbital coordinate system, and regard the calculated sun angle as the sun angle in the guide mirror coordinate system; Step 9: Determine whether the sign of the solar angle is corrected on-orbit. If so, proceed to step 10. If not, terminate the calculation and correction of the solar angle on-orbit. Step 10: Correct the sign of the solar angle according to the data injection sign parameter. After correction, the calculation and correction of the on-orbit solar angle are completed.

2. The on-orbit solar angle calculation and correction method according to claim 1, characterized in that: Step three includes the following steps: Step 31: Use the satellite attitude to transform the sun vector in the orbital coordinate system to the satellite coordinate system; Step 32: Use the installation matrix between the two-dimensional rotation mechanism installation surface coordinate system and the satellite coordinate system to transform the sun vector in the satellite coordinate system to the two-dimensional rotation mechanism installation surface coordinate system; Step 33: Use the installation matrix between the two-dimensional rotation mechanism axis coordinate system and the two-dimensional rotation mechanism installation surface coordinate system to transform the solar vector in the two-dimensional rotation mechanism installation surface coordinate system to the two-dimensional rotation mechanism axis coordinate system.

3. A satellite-borne software running on a solar remote sensing instrument, characterized in that: Used to execute the on-orbit solar angle calculation and correction method as described in claim 1 or 2.

4. The satellite-borne software according to claim 3, characterized in that: The onboard software controls the two-dimensional rotation mechanism according to the solar angle calculated in step seven or step eight or the solar angle corrected in step ten to achieve solar capture.

Images