Laser link pointing calculation method and system in GEO satellite attitude adjustment

Abstract

The invention provides a laser link pointing calculation method and system in GEO satellite attitude adjustment. The method comprises the following steps: S1, establishing a laser link two-dimensional turntable coordinate system and a satellite body coordinate system; s2, calculating in a satellite body coordinate system to obtain a first laser link pointing vector and a conversion matrix; s3, calculating in the reference coordinate system of the laser two-dimensional turntable to obtain a second laser link pointing vector; and S4, calculating according to the first laser link pointing vector, the second laser link pointing vector and the conversion matrix to obtain an azimuth angle and a pitch angle of the laser link two-dimensional turntable. The method can adapt to the stable tracking and pointing of the laser link to the link building target satellite under the attitude yaw U-turn scene of the link building satellite, and during the attitude yaw U-turn maneuvering period, the azimuth axis rapid driving is carried out when the laser link two-dimensional turntable is selected to be vertical to the orbital plane, so that the link building interruption time is shortest, and the optimal efficiency of link building between the orbital satellites is ensured.

Description

Technical Field

[0001] The present invention relates to the field of space exploration technology. Specifically, it relates to a method and system for calculating the pointing of a laser link in the attitude adjustment of a GEO satellite, especially a method and system for calculating the pointing of a two-dimensional turntable of a laser link applicable to the attitude turning maneuver scenario of a GEO satellite. Background Technique

[0002] China is vigorously developing a high-orbit satellite remote sensing constellation. How to achieve fast transmission of image-level large data volume between satellites is a current challenge. At present, the laser link is the means with the highest communication rate in space applications. However, the beam divergence angle of the laser link is more than two orders of magnitude smaller than the beam angle of the inter-satellite link in the microwave system. Therefore, in the scenarios of the attitude movement of the local satellite during link establishment and the slow movement of the orbits of the two satellites during link establishment, how to ensure the accurate and stable pointing of the two-dimensional turntable of the laser link poses high requirements for engineering implementation.

[0003] After investigation, the relevant thesis and patent documents are as follows, but none of them involve the calculation of the pointing of the two-dimensional turntable of the laser link in the attitude turning maneuver scenario of a GEO satellite.

[0004] The thesis "Analysis and Compensation Control of the Optical Axis Pointing Error Sources of Inter-Satellite Laser Communication Machines" (Liu Zhenglin, Wang Yiqun, etc. Analysis and Compensation Control of the Optical Axis Pointing Error Sources of Inter-Satellite Laser Communication Machines [J]. Journal of Astronautics, 2023, 44(3): 455-464.) proposed a compensation scheme based on an error correction matrix for the optical axis pointing deviation caused by the installation errors of each optical element in the rear optical path of the inter-satellite laser communication machine, significantly reducing the influence of installation errors on the optical axis pointing accuracy. The biggest difference from the present invention is that it did not carry out research on the coupling between the laser mid-section pointing and the satellite attitude in the scenario of the attitude yaw turning maneuver of a GEO satellite.

[0005] The thesis "Research on Error Separation in the Calibration of the Pointing Error of a Laser Inter-Satellite Link Terminal" (Cheng Jingshuang, Lin Yiming, He Shanbao, Wang Haihong, etc. Research on Error Separation in the Calibration of the Pointing Error of a Laser Inter-Satellite Link Terminal [J]. Journal of Astronautics, 2019, 40(1): 85-93.) proposed a method for separating the spacecraft attitude measurement errors based on multi-link measurement for the problem that the spacecraft attitude measurement errors affect the calibration results in the on-orbit calibration of the pointing error of the laser inter-satellite link terminal. The biggest difference from the present invention is that it did not carry out research on the coupling between the laser mid-section pointing and the satellite attitude in the scenario of the attitude yaw turning maneuver of a GEO satellite.

[0006] The paper "Influence of On-Orbit Maneuver of Spaceborne Laser Communication Terminal on Temperature" (Liu Shaoran, Li Yifan, Zhang Wenrui, Tao Jiasheng, etc. Influence of On-Orbit Maneuver of Spaceborne Laser Communication Terminal on Temperature [J]. Journal of Astronautics, 2018, 39(11): 85-93.) carried out simulations on the transient temperature changes of the laser communication terminal in orbit, aiming to study the influence of on-orbit maneuvers, simplify the simulation of maneuver modes in thermal analysis and thermal tests, and focus on the analysis of the temperature field. The biggest difference from the present invention is that it did not carry out research on the coupling between the laser mid-section pointing and the satellite attitude in the scenario of the GEO satellite attitude yaw turn maneuver.

[0007] The patent "Method for Establishing Laser Link between Low-Earth Orbit Satellite and Ground Station" (Patent No.: ZL200610009891.2) solves the problem that the existing ground terminal and on-board terminal both need to perform scanning when establishing a laser link, resulting in a long capture time, and it is not the application scenario of high-orbit GEO inter-satellite link establishment proposed by the present invention.

[0008] The patent "Static Output Feedback PI Beam Stabilization Control Method for High-Orbit Satellite-Satellite Laser Link" (Patent No.: ZL201510962797.8) solves the problem of complex parameter selection of the PI controller in the existing tracking system of communication laser beams, focusing on the tuning of controller parameters, and it is not the application scenario of high-orbit GEO inter-satellite link establishment proposed by the present invention.

[0009] The patent "A Simplified Test Verification System Suitable for Laser-Microwave Hybrid Link Switching" (Patent No.: ZL201710537680.4) is mainly used for the simplified test verification of laser-microwave hybrid link switching, and it is not the application scenario of high-orbit GEO inter-satellite laser link establishment proposed by the present invention. Summary of the Invention

[0010] Aiming at the defects in the prior art, the purpose of the present invention is to provide a method and system for calculating the laser link pointing in the GEO satellite attitude adjustment.

[0011] According to a method for calculating the laser link pointing in the GEO satellite attitude adjustment provided by the present invention, it includes:

[0012] Step S1: Establish a two-dimensional turntable coordinate system of the laser link and a satellite body coordinate system;

[0013] The two-dimensional turntable coordinate system of the laser link includes a laser two-dimensional turntable reference coordinate system and a laser detector fixed coordinate system;

[0014] Step S2: Calculate the first laser link pointing vector and transformation matrix in the satellite body coordinate system;

[0015] Step S3: Calculate the second laser link pointing vector in the laser two-dimensional turntable reference coordinate system;

[0016] Step S4: Calculate the azimuth angle and pitch angle of the laser link two-dimensional turntable based on the first laser link pointing vector, the second laser link pointing vector, and the transformation matrix.

[0017] Preferably, it further includes:

[0018] Step S5: Complete the switching of the target star for bilateral laser link establishment with satellite attitude linkage based on the calculation results;

[0019] Step S6: Simulate the pointing process of the laser link two-dimensional turntable in the GEO satellite attitude turning maneuver scenario to obtain the simulation results.

[0020] Preferably, the step S1 includes the following sub-steps:

[0021] Step S1.1: Establish the reference coordinate system O of the laser two-dimensional turntable jz X jz Y jz Z jz ;

[0022] Take the centroid position of the laser two-dimensional turntable as the origin O jz , and the direction perpendicular to the installation surface of the laser two-dimensional turntable upward as O jz Z jz axis, and the direction along the azimuth axis of the laser two-dimensional turntable as O jz Y jz axis; Based on the right-hand rule, multiply the O jz Z jz axis and the O jz Y jz axis crosswise to obtain the O jz X jz axis;

[0023] The reference coordinate system of the laser two-dimensional turntable is fixed relative to the satellite body;

[0024] Step S1.2: Establish the coordinate system O fixedly connected to the laser detector sd X sd Y sd Z sd ;

[0025] Take the intersection of the azimuth axis and the pitch axis of the laser two-dimensional turntable as the origin O sd , and the direction along the optical axis of the laser lens as O sd X sd axis, and the direction along the pitch axis of the laser two-dimensional turntable as O sd Z sd axis; Based on the right-hand rule, from O sd Z sd axis and O sd Xsd The axes are cross - multiplied to obtain O sd Y sd axis;

[0026] The fixed - connection coordinate system of the laser detector is a follow - up coordinate system, which moves following the rotation of the two - dimensional turntable;

[0027] When both the azimuth angle and the pitch angle of the two - dimensional turntable are zero, the corresponding coordinate axes of the laser two - dimensional turntable reference coordinate system and the fixed - connection coordinate system of the laser detector are parallel to each other.

[0028] Preferably, the step S2 includes:

[0029] Let the laser link pointing vector between G - G stars be L, which is expressed as L in the inertial system i ; Let the position of the local star in the inertial system be r local , and the position of the target star in the inertial system be r tar , then:

[0030]

[0031] Let the laser link pointing vector be expressed as L in the orbital system o , denoted as L o = [L ox L oy L oz T , then:

[0032] L o = A oi L i

[0033] where A oi is the transformation matrix of the local star's orbital coordinate system relative to the inertial system;

[0034] Let the laser link pointing vector in the satellite body coordinate system be L b , denoted as L b = [L bx L by L bz T , then:

[0035] L b = A bo L o

[0036] where A bo is the transformation matrix of the local star's body coordinate system relative to the orbital coordinate system.

[0037] Preferably, the step S3 includes:

[0038] ​​Let the laser link pointing vector be L in the pitch servo coordinate system sd , and this vector servo-tracks the target star, so we have:

[0039] L sd = [1 0 0] T

[0040] Let the angle of the two-dimensional turntable around the pitch axis be α and the angle around the azimuth axis be β. Then the pointing vector L in the turntable reference coordinate system jz is:

[0041] L jz = R y (-β)R z (-α)L sd

[0042] where R z is the rotation matrix around the Z axis, and R y is the rotation matrix around the Y axis.

[0043] Preferably, the step S4 includes:

[0044] In the satellite body coordinate system, the representation of the laser pointing vector includes:

[0045] L b = A bo L o = A bjz L jz = A bjz R y (-β)R z (-α)L sd

[0046] In the formula, A bjz is the transformation matrix from the laser two-dimensional turntable reference coordinate system to the satellite body coordinate system;

[0047] Simplify the intermediate variables to get:

[0048] A bo L o = A bjz R y (-β)R z (-α)L sd

[0049] Expand to get:

[0050]

[0051] According to the above formula, solve the equation to obtain the two angles α and β of the two-dimensional turntable.

[0052] Preferably, the step S5 includes:

[0053] According to the layout of the satellite attitude and the two-dimensional turntable of the laser link, during the yaw attitude maneuver of the satellite, when the azimuth axis of the two-dimensional turntable of the laser link is perpendicular to the satellite orbit plane, drive the two-dimensional turntable to maneuver around the azimuth axis to achieve the east-west switching of the target star for establishing a link in the GEO orbit.

[0054] Preferably, the step S6 includes:

[0055] Set the time series and the simulation step size, gradually calculate the satellite attitude and the orbit of the target star for establishing a link at each moment, calculate the pointing of the two-dimensional turntable of the laser link, and combine the target star switching method to obtain the calculation results of the azimuth angle and the pitch angle over the entire time series.

[0056] A laser link pointing calculation system in the GEO satellite attitude adjustment provided by the present invention includes:

[0057] Module M1: Establish a coordinate system for the two-dimensional turntable of the laser link and a satellite body coordinate system;

[0058] The coordinate system for the two-dimensional turntable of the laser link includes a reference coordinate system for the two-dimensional turntable of the laser and a coordinate system fixedly connected to the laser detector;

[0059] Module M2: Calculate the first laser link pointing vector and the transformation matrix in the satellite body coordinate system;

[0060] Module M3: Calculate the second laser link pointing vector in the reference coordinate system for the two-dimensional turntable of the laser;

[0061] Module M4: Calculate the azimuth angle and the pitch angle of the two-dimensional turntable of the laser link based on the first laser link pointing vector, the second laser link pointing vector, and the transformation matrix.

[0062] Preferably, it further includes:

[0063] Module M5: Complete the switching of the target star for bilateral laser link establishment with satellite attitude linkage based on the calculation results;

[0064] Module M6: Simulate the pointing process of the two-dimensional turntable of the laser link in the GEO satellite attitude turning maneuver scenario to obtain the simulation results.

[0065] Preferably, the module M1 includes the following sub-modules:

[0066] Module M1.1: Establish a reference coordinate system O jz X jz Y jz Z jz ;

[0067] Take the centroid position of the two-dimensional turntable of the laser as the origin O jz, the direction upward of the installation surface of the vertical laser two-dimensional turntable is taken as O jz Z jz axis, and the direction along the azimuth axis of the laser two-dimensional turntable is taken as O jz Y jz axis; Based on the right-hand rule, cross-multiplying the O jz Z jz axis and the O jz Y jz axis gives the O jz X jz axis;

[0068] The reference coordinate system of the laser two-dimensional turntable is fixed relative to the satellite body;

[0069] Module M1.2: Establish the coordinate system O sd X sd Y sd Z sd ;

[0070] Take the intersection point of the azimuth axis and the pitch axis of the laser two-dimensional turntable as the origin O sd , and the direction along the optical axis of the laser lens is taken as O sd X sd axis, and the direction along the pitch axis of the laser two-dimensional turntable is taken as O sd Z sd axis; Based on the right-hand rule, from O sd Z sd axis and O sd X sd axis cross-multiplying gives O sd Y sd axis;

[0071] The coordinate system fixedly connected to the laser detector is a follow-up coordinate system, which moves with the rotation of the two-dimensional turntable;

[0072] When both the azimuth angle and the pitch angle of the two-dimensional turntable are zero, the corresponding coordinate axes of the reference coordinate system of the laser two-dimensional turntable and the coordinate system fixedly connected to the laser detector are parallel to each other.

[0073] Preferably, the module M2 includes:

[0074] Let the G-G inter-satellite laser link pointing vector be L, which is expressed as L i in the inertial system; Let the position of this satellite in the inertial system be r local , and the position of the target satellite in the inertial system be r tar , then:

[0075]

[0076] Let the laser link pointing vector be expressed as L o in the orbital system, denoted as Lo = [L ox L oy L oz T , then:

[0077] L o = A oi L i

[0078] where A oi is the transformation matrix of the satellite's orbital coordinate system relative to the inertial coordinate system;

[0079] Suppose the laser link pointing vector in the satellite body coordinate system is L b , denoted as L b = [L bx L by L bz T , then:

[0080] L b = A bo L o

[0081] where A bo is the transformation matrix of the satellite's body coordinate system relative to the orbital coordinate system.

[0082] Preferably, the module M3 includes:

[0083] Suppose the laser link pointing vector in the pitch servo coordinate system is L sd , and this vector servo-tracks the target star, then:

[0084] L sd = [1 0 0] T

[0085] Suppose the two-dimensional turntable rotates by an angle α around the pitch axis and by an angle β around the azimuth axis, then the pointing vector L jz in the turntable reference coordinate system is:

[0086] L jz = R y (-β)R z (-α)L sd

[0087] where R z is the rotation matrix around the Z axis, and R y is the rotation matrix around the Y axis.

[0088] Preferably, the module M4 includes:

[0089] In the satellite body coordinate system, the representation of the laser pointing vector includes: ​​

[0090] L b = A bo L o = A bjz L jz = A bjz R y (-β)R z (-α)L sd

[0091] Wherein, A bjz is the conversion matrix from the reference coordinate system of the laser two-dimensional turntable to the satellite body coordinate system;

[0092] Simplify the intermediate variables to obtain:

[0093] A bo L o = A bjz R y (-β)R z (-α)L sd

[0094] Expand to obtain:

[0095]

[0096] According to the above formula, solve the equation to obtain the two rotation angles α and β of the two-dimensional turntable.

[0097] Preferably, the module M5 includes:

[0098] According to the layout of the satellite attitude and the laser link two-dimensional turntable, during the yaw attitude maneuver of the satellite, when the azimuth axis of the laser link two-dimensional turntable is perpendicular to the satellite orbit plane, drive the two-dimensional turntable to maneuver around the azimuth axis to achieve the east-west switching of the target star for establishing a link in the GEO orbit.

[0099] Preferably, the module M6 includes:

[0100] Set the time series and simulation step size, gradually calculate the satellite attitude and the orbit of the target star for establishing a link at each moment, calculate the pointing of the laser link two-dimensional turntable, and combine the target star switching method to obtain the calculation results of the azimuth angle and pitch angle over the entire time series.

[0101] Compared with the prior art, the present invention has the following beneficial effects:

[0102] 1. The present invention can adapt to the stable tracking and pointing of the laser link to the target star for establishing a link in the scenario of the yaw turn of the attitude of the satellite for establishing a link. During the yaw turn maneuver of the attitude, select the time when the laser link two-dimensional turntable is perpendicular to the orbit plane to perform rapid driving of the azimuth axis, so that the link interruption time is the shortest, ensuring the optimal in-orbit inter-satellite link establishment efficiency.

[0103] 2. In the present invention, the laser link pointing algorithm can adapt to satellite application scenarios with different orbital altitudes. The laser link pointing is calculated in real time based on satellite attitude and dual (multi)-satellite orbit information, and is fully autonomous without ground intervention, facilitating user operation.

[0104] Other beneficial effects of the present invention will be described in the specific embodiments through the introduction of specific technical features and technical solutions. Those skilled in the art should be able to understand the beneficial technical effects brought by the described technical features and technical solutions through these introductions. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] By reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent:

[0106] Figure 1 It is a schematic diagram of the principle of the laser link two-dimensional turntable pointing calculation method applicable to the GEO satellite attitude turning maneuver scenario in the present invention.

[0107] Figure 2 It is a schematic diagram of the definition of the laser link two-dimensional turntable coordinate system in the present invention.

[0108] Figure 3 It is a schematic diagram of the layout of the laser link dual terminals in the satellite mechanical coordinate system in the present invention.

[0109] Figure 4 It is a curve of the satellite three-axis attitude and the simulation result curve of the laser link two-dimensional turntable rotation angle in the daily attitude turning scenario of the GEO satellite in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0110] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill 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.

[0111] The present invention provides a laser link two-dimensional turntable pointing calculation method applicable to the GEO satellite attitude turning maneuver scenario, which relates to the field of spacecraft dynamics and control. It includes the laser link two-dimensional turntable coordinate system definition method; the laser link pointing vector calculation method in the satellite body coordinate system; the laser link pointing vector calculation method in the turntable reference coordinate system; the conversion matrix calculation method from the turntable reference system to the satellite body system; the laser link two-dimensional turntable azimuth and pitch angle calculation method; the bilateral laser link target star fast switching method linked with the satellite attitude; and the laser link two-dimensional turntable pointing simulation method in the GEO satellite attitude turning maneuver scenario.

[0112] Reference Figure 1 As shown, a method for calculating the pointing of a two-dimensional turntable of a laser link applicable to the attitude turning maneuver scenario of a GEO satellite includes:

[0113] Step 1: Method for defining the coordinate system of the two-dimensional turntable of the laser link;

[0114] Reference Figure 2 As shown, ① Define the reference coordinate system O jz X jz Y jz Z jz :

[0115] The origin O jz : Located at the centroid position of the two-dimensional turntable of the laser;

[0116] O jz Z jz axis: Perpendicular to the installation surface of the two-dimensional turntable of the laser and upward;

[0117] O jz Y jz axis: Along the azimuth axis direction of the two-dimensional turntable of the laser;

[0118] O jz X jz axis: Satisfies the right-hand rule and is obtained by cross-multiplying the O jz Z jz axis and the O jz Y jz axis.

[0119] This coordinate system is fixed relative to the satellite body.

[0120] ② Define the coordinate system O sd X sd Y sd Z sd :

[0121] The origin O sd : Located at the intersection of the azimuth axis and the pitch axis of the two-dimensional turntable of the laser;

[0122] O sd X sd axis: Along the optical axis direction of the laser optical lens;

[0123] O sd Z sd axis: Along the pitch axis direction of the two-dimensional turntable of the laser;

[0124] O sd Y sd axis: Satisfies the right-hand rule and is obtained by cross-multiplying the O sd Z sd axis and the O sd Xsd Obtained by the cross product of the axes.

[0125] This coordinate system moves as the two-dimensional turntable rotates and is a follow-up coordinate system.

[0126] When the two azimuth angles and pitch angles of the two-dimensional turntable are both zero, the corresponding coordinate axes of the above two coordinate systems are parallel to each other.

[0127] Step 2: Method for calculating the laser link pointing vector in the satellite body coordinate system;

[0128] Let the laser link pointing vector between satellite G and the target satellite be L, which is expressed as L in the inertial system i , and can be obtained from the orbits of the two satellites for establishing the link. Let the position of the local satellite in the inertial system be r local , and the position of the target satellite in the inertial system be r tar , then we can get:

[0129]

[0130] Let the laser link pointing vector be expressed as L in the orbit coordinate system o , denoted as L o = [L ox L oy L oz T , then we can get:

[0131] L o = A oi L i

[0132] where A oi is the transformation matrix of the local satellite orbit coordinate system relative to the inertial system.

[0133] Let the laser link pointing vector in the satellite body coordinate system be L b , denoted as L b = [L bx L by L bz T , then we can get:

[0134] L b = A bo L o

[0135] where A bo is the transformation matrix of the local satellite body coordinate system relative to the orbit coordinate system.

[0136] Step 3: Method for calculating the laser link pointing vector in the turntable reference coordinate system;

[0137] Let the pointing vector of the laser link in the pitch servo coordinate system be L sd , since this vector servo-tracks the target star, we have:

[0138] L sd = [1 0 0] T

[0139] Let the rotation angle of the two-dimensional turntable around the pitch axis be α and the rotation angle around the azimuth axis be β. Then, the pointing vector L in the turntable reference coordinate system can be obtained as: jz :

[0140] L jz = R y (-β)R z (-α)L sd

[0141] where R z is the rotation matrix about the Z axis, and R y is the rotation matrix about the Y axis.

[0142] Step 4: Calculation method of the transformation matrix from the turntable reference system to the satellite body system;

[0143] As shown in the installation layout of the two optical heads Figure 3 shown, it can be known that:

[0144] From the laser head I reference coordinate system to the satellite body system: rotate -150° about the Z axis and then 180° about the X axis, that is:

[0145]

[0146] From the laser head II reference coordinate system to the satellite body system: rotate 60° about the Z axis and then 180° about the X axis, that is:

[0147]

[0148] Step 5: Calculation method of the azimuth angle and pitch angle of the laser link two-dimensional turntable;

[0149] In the satellite body system, the laser pointing vector can be expressed as

[0150] L b = A bo L o = A bjz L jz = A bjz R y (-β)R z (-α)L sd

[0151] Simplifying the intermediate variables, we can get

[0152] Abo L o = A bjz R y (-β)R z (-α)L sd

[0153] Expanding gives

[0154]

[0155] According to the above equation, the two rotation angles α and β of the two-dimensional turntable can be obtained by solving the equation.

[0156] For laser head I and laser head II, A bjz are both skew-symmetric matrices. Without loss of generality, let them be

[0157]

[0158] Substituting gives

[0159]

[0160] Simplifying gives

[0161]

[0162] Since β ∈ [0, π), so solving according to the above equation gives

[0163]

[0164] Step 6: A fast target star switching method for bilateral laser link establishment linked to satellite attitude;

[0165] According to the layout of the satellite attitude and the two-dimensional turntable of the laser link, taking the layout of Figure 3 as an example, during the yaw attitude maneuver of the satellite, when the azimuth axis of the two-dimensional turntable of the laser link is perpendicular to the satellite orbit plane, drive the two-dimensional turntable to quickly maneuver around the azimuth axis to achieve the east-west switching of the link establishment target star on the GEO orbit. The maneuvering angle of the azimuth axis can be calculated from the fixed-point longitudes of the link establishment target star and the link establishment home star.

[0166] Step 7: A simulation method for the pointing of the two-dimensional turntable of the laser link in the scenario of the attitude turning maneuver of the GEO satellite.

[0167] Set the time series and simulation step size, and gradually calculate the satellite attitude and the orbit of the link establishment target star at each moment. Calculate the pointing of the two-dimensional turntable of the laser link according to the aforementioned steps 2 - 5, and combine the target star switching method in step 6 to obtain the calculation results of the azimuth angle and elevation angle over the entire time series. Taking the laser head II of Figure 3 as an example, the variation laws of the azimuth angle and elevation angle of the two-dimensional turntable of the laser link within one day are asFigure 4 as shown

[0168] The present invention further provides a laser link pointing calculation system in GEO satellite attitude adjustment. The laser link pointing calculation system in GEO satellite attitude adjustment can be implemented by executing the process steps of the laser link pointing calculation method in GEO satellite attitude adjustment. That is, those skilled in the art can understand the laser link pointing calculation method in GEO satellite attitude adjustment as the preferred implementation manner of the laser link pointing calculation system in GEO satellite attitude adjustment.

[0169] Specifically, a laser link pointing calculation system in GEO satellite attitude adjustment includes:

[0170] Module M1: Establish a two-dimensional turntable coordinate system of the laser link and a satellite body coordinate system;

[0171] The two-dimensional turntable coordinate system of the laser link includes a laser two-dimensional turntable reference coordinate system and a laser detector fixed coordinate system;

[0172] Module M2: Calculate the first laser link pointing vector and the transformation matrix in the satellite body coordinate system;

[0173] Module M3: Calculate the second laser link pointing vector in the laser two-dimensional turntable reference coordinate system;

[0174] Module M4: Calculate the azimuth angle and pitch angle of the laser link two-dimensional turntable according to the first laser link pointing vector, the second laser link pointing vector and the transformation matrix.

[0175] It further includes:

[0176] Module M5: Complete the switching of the bilateral laser link target star for satellite attitude linkage based on the calculation results;

[0177] Module M6: Simulate the laser link two-dimensional turntable pointing process in the GEO satellite attitude turning maneuver scenario to obtain the simulation results.

[0178] The Module M1 includes the following sub-modules:

[0179] Module M1.1: Establish a laser two-dimensional turntable reference coordinate system O jz X jz Y jz Z jz ;

[0180] Take the centroid position of the laser two-dimensional turntable as the origin O jz and the direction perpendicular to the laser two-dimensional turntable mounting surface upward as O jz Z jz axis, and the direction along the azimuth axis of the laser two-dimensional turntable as Ojz Y jz axis; Based on the right - hand rule, cross - multiply the O jz Z jz axis and the O jz Y jz axis to obtain the O jz X jz axis;

[0181] The reference coordinate system of the laser two - dimensional turntable is fixed relative to the satellite body;

[0182] Module M1.2: Establish the coordinate system O sd X sd Y sd Z sd ;

[0183] Take the intersection point of the azimuth axis and the pitch axis of the laser two - dimensional turntable as the origin O sd , and the direction along the optical axis of the laser lens is the O sd X sd axis, and the direction along the pitch axis of the laser two - dimensional turntable is the O sd Z sd axis; Based on the right - hand rule, cross - multiply the O sd Z sd axis and the O sd X sd axis to obtain the O sd Y sd axis;

[0184] The coordinate system fixed to the laser detector is a follow - up coordinate system, which moves with the rotation of the two - dimensional turntable;

[0185] When both the azimuth angle and the pitch angle of the two - dimensional turntable are zero, the corresponding coordinate axes of the reference coordinate system of the laser two - dimensional turntable and the coordinate system fixed to the laser detector are parallel to each other.

[0186] The module M2 includes:

[0187] Let the pointing vector of the G - G inter - satellite laser link be L, which is expressed as L i in the inertial system; Let the position of the local satellite in the inertial system be r local , and the position of the target satellite in the inertial system be r tar , then:

[0188]

[0189] Let the pointing vector of the laser link be expressed as L o in the orbital system, denoted as L o =[L ox L oy L oz T ​, then:

[0190] L o = A oi L i

[0191] where, A oi is the transformation matrix of the satellite orbit coordinate system relative to the inertial system;

[0192] Assume that the laser link pointing vector in the satellite body coordinate system is L b , denoted as L b = [L bx L by L bz T , then:

[0193] L b = A bo L o

[0194] where, A bo is the transformation matrix of the satellite body coordinate system relative to the orbit coordinate system.

[0195] The module M3 includes:

[0196] Assume that the laser link pointing vector in the pitch servo coordinate system is L sd , and this vector servo-tracks the target star, then:

[0197] L sd = [1 0 0] T

[0198] Assume that the two-dimensional turntable rotates by an angle α around the pitch axis and by an angle β around the azimuth axis. Then the pointing vector L jz in the turntable reference coordinate system is:

[0199] L jz = R y (-β)R z (-α)L sd

[0200] where, R z is the rotation matrix around the Z axis, and R y is the rotation matrix around the Y axis.

[0201] The module M4 includes:

[0202] In the satellite body coordinate system, the representation of the laser pointing vector includes:

[0203] L b = A bo L o = A bjz L jz ​= A bjz R y (-β)R z (-α)L sd

[0204] Wherein, A bjz is the conversion matrix from the reference coordinate system of the laser two-dimensional turntable to the satellite body coordinate system;

[0205] Simplify the intermediate variables to obtain:

[0206] A bo L o = A bjz R y (-β)R z (-α)L sd

[0207] Expand to obtain:

[0208]

[0209] According to the above formula, solve the equation to obtain the two rotation angles α and β of the two-dimensional turntable.

[0210] The module M5 includes:

[0211] According to the layout of the satellite attitude and the laser link two-dimensional turntable, during the satellite yaw attitude maneuver, when the azimuth axis of the laser link two-dimensional turntable is perpendicular to the satellite orbital plane, drive the two-dimensional turntable to maneuver around the azimuth axis to achieve the east-west switching of the target star for establishing a link in the GEO orbit.

[0212] The module M6 includes:

[0213] Set the time series and the simulation step size, gradually calculate the satellite attitude and the target star orbit for establishing a link at each moment, calculate the pointing of the laser link two-dimensional turntable, and combine the target star switching method to obtain the calculation results of the azimuth angle and the pitch angle over the entire time series.

[0214] Those skilled in the art know that in addition to implementing the system and its various devices, modules, and units provided by the present invention in the form of pure computer-readable program code, the method steps can be logically programmed to enable the system and its various devices, modules, and units provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc., to achieve the same functions. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be regarded as the structure within the hardware component; the devices, modules, and units for implementing various functions can also be regarded as either software modules for implementing the method or the structure within the hardware component.

[0215] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, 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. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A laser link pointing calculation method in the attitude adjustment of GEO satellites, characterized in that Including: Step S1: Establish the two-dimensional turntable coordinate system of the laser link and the satellite body coordinate system; The two-dimensional turntable coordinate system of the laser link includes the laser two-dimensional turntable reference coordinate system and the laser detector fixed coordinate system; Step S2: Calculate the first laser link pointing vector and the transformation matrix in the satellite body coordinate system; Step S3: Calculate the second laser link pointing vector in the laser two-dimensional turntable reference coordinate system; Step S4: Calculate the azimuth angle and pitch angle of the two-dimensional turntable of the laser link based on the first laser link pointing vector, the second laser link pointing vector and the transformation matrix.

2. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 1, characterized in that Also including: Step S5: Complete the switching of the bilateral laser link target star for satellite attitude linkage based on the calculation results; Step S6: Simulate the pointing process of the two-dimensional turntable of the laser link in the GEO satellite attitude turning maneuver scenario to obtain the simulation results.

3. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 1, wherein, The said Step S1 includes the following sub-steps: Step S1.1: Establish the reference coordinate system O of the laser two-dimensional turntable jz X jz Y jz Z jz ; Take the centroid position of the laser two-dimensional turntable as the origin O jz , and the direction perpendicular to the installation surface of the laser two-dimensional turntable upward as the O jz Z jz axis, and the direction along the azimuth axis of the laser two-dimensional turntable as the O jz Y jz axis; Based on the right-hand rule, multiply the O jz Z jz axis and the O jz Y jz axis crosswise to obtain the O jz X jz axis; The laser two-dimensional turntable reference coordinate system is fixed relative to the satellite body; Step S1.2: Establish the fixed coordinate system O of the laser detector sd X sd Y sd Z sd ; Take the intersection point of the azimuth axis and the pitch axis of the laser two-dimensional turntable as the origin O sd , and the direction along the optical axis of the laser optical lens is the O sd X sd axis, and the direction along the pitch axis of the laser two-dimensional turntable is the O sd Z sd axis; Based on the right-hand rule, from O sd Z sd axis and O sd X sd axis cross-multiply to get O sd Y sd axis; The laser detector fixed coordinate system is a follow-up coordinate system that moves with the rotation of the two-dimensional turntable; When both the azimuth angle and pitch angle of the two-dimensional turntable are zero, the corresponding coordinate axes of the laser two-dimensional turntable reference coordinate system and the laser detector fixed coordinate system are parallel to each other.

4. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 3, wherein The said Step S2 includes: Let the pointing vector of the laser link between satellite G and satellite G* be L, which is expressed as L in the inertial frame i ; Let the position of this satellite in the inertial frame be r local , and the position of the target satellite in the inertial frame be r tar , then Let the laser link pointing vector be represented as L in the orbital system o , denoted as L o = [L ox L oy L oz T , then:​ L o = A oi L i where A oi is the transformation matrix of the satellite orbit coordinate system relative to the inertial system; Let the laser link pointing vector be \(L\) in the satellite body coordinate system b , denoted as \(L\) b =\([L bx _{L by} bz T , then:​ L b = A bo L o Among them, A bo is the transformation matrix of the local celestial coordinate system relative to the orbital coordinate system.

5. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 4, characterized in that, The said Step S3 includes: Let the laser link pointing vector be L in the pitch servo coordinate system sd , and this vector servo-tracks the target star, so we have: L sd ＝[100] T Let the rotation angle of the two-dimensional turntable about the pitch axis be α and the rotation angle about the azimuth axis be β. Then the pointing vector L in the turntable reference coordinate system jz is as follows: L jz = R y (-β)R z (-α)L sd Among them, R z is the rotation matrix around the Z-axis, and R y is the rotation matrix around the Y-axis.

6. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 5, wherein, The said Step S4 includes: In the satellite body coordinate system, the representation of the laser pointing vector includes: L b = A bo L o = A bjz L jz = A bjz R y (-β)R z (-α)L sd Where, A bjz is the transformation matrix from the reference coordinate system of the two-dimensional laser turntable to the satellite body coordinate system; Simplify the intermediate variables to get: A bo L o = A bjz R y (-β)R z (-α)L sd Expand to get: According to the above formula, solve the equation to obtain the two rotation angles α and β of the two-dimensional turntable.

7. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 2, characterized in that, The said Step S5 includes: According to the satellite attitude and the layout of the two-dimensional turntable of the laser link, during the satellite yaw attitude maneuver, when the azimuth axis of the two-dimensional turntable of the laser link is perpendicular to the satellite orbit plane, drive the two-dimensional turntable to maneuver around the azimuth axis to realize the east-west switching of the link target star on the GEO orbit.

8. The laser link pointing calculation method in the GEO satellite attitude adjustment according to claim 7, wherein, The said Step S6 includes: Set the time series and simulation step size, gradually calculate the satellite attitude and the orbit of the link target star at each moment, calculate the pointing of the two-dimensional turntable of the laser link, and combine the target star switching method to obtain the calculation results of the azimuth angle and pitch angle in the entire time series.

9. A laser link pointing calculation system in the attitude adjustment of a GEO satellite, characterized in that, Including: Module M1: Establish the two-dimensional turntable coordinate system of the laser link and the satellite body coordinate system; The two-dimensional turntable coordinate system of the laser link includes the laser two-dimensional turntable reference coordinate system and the laser detector fixed coordinate system; Module M2: Calculate the first laser link pointing vector and the transformation matrix in the satellite body coordinate system; Module M3: Calculate the second laser link pointing vector in the laser two-dimensional turntable reference coordinate system; Module M4: Calculate the azimuth angle and pitch angle of the two-dimensional turntable of the laser link based on the first laser link pointing vector, the second laser link pointing vector and the transformation matrix.

10. The laser link pointing calculation system in the GEO satellite attitude adjustment according to claim 9, wherein Also including: Module M5: Complete the switching of the bilateral laser link target star for satellite attitude linkage based on the calculation results; Module M6: Simulate the pointing process of the two-dimensional turntable of the laser link in the GEO satellite attitude turning maneuver scenario to obtain the simulation results.

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