Non-orthogonal analysis and correction method and system for two-dimensional turntable of laser terminal

Abstract

The invention provides a laser terminal two-dimensional turntable non-orthogonal analysis and correction method and system, and the method comprises the steps: 1, building a reference coordinate system for a typical two-dimensional turntable mechanism, and describing the rotation mode of a two-dimensional turntable; 2, establishing a model that the two-dimensional rotary table drives the optical axis of the laser terminal to rotate when no non-orthogonal error exists; 3, considering the influence of the non-orthogonal error on the optical axis direction of the laser terminal, and establishing a non-orthogonal optical axis direction transmission model; and step 4, establishing a calibration method according to the non-orthogonal optical axis pointing error model, and realizing nonlinear correction under a large-range rotation angle. The method can adapt to correction under large-range rotation, fundamentally solves the non-orthogonal influence compared with a traditional linear fitting method, and is higher in implementation precision.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite overall design and attitude control, and in particular to a non-orthogonal analysis and correction method and system for a two-dimensional turntable of a laser terminal. Background Art

[0002] The optical axis pointing accuracy is the core indicator of the laser terminal. Since the communication beam angle of the laser terminal is very small, generally 10 -5 In order to ensure that the laser accurately points to the communication target and establishes the communication state, it is required to accurately measure the precise pointing of the optical axis of the laser terminal in the inertial space. However, due to the influence of factors such as installation error, launch vibration, and on-orbit stress release on the two-dimensional turntable, the rotation axis installation of the rotating mechanism has non-orthogonal characteristics. The actual rotation angle calculation of the two-dimensional turntable cannot truly reflect the pointing of the laser terminal in the inertial space. The larger the rotation angle of the two-dimensional turntable, the greater the optical axis pointing measurement error. In order to improve the optical axis pointing accuracy of the laser terminal, it is necessary to carry out non-orthogonal analysis and correction method research on the two-dimensional turntable of the laser terminal.

[0003] After literature research, a spacecraft attitude measurement error separation method based on multi-link measurement was proposed in the paper "Error Separation Research in Pointing Error Calibration of Laser Intersatellite Link Terminal" (Journal of Astronautics, Vol. 40, No. 1, 2019). This method takes advantage of the fact that the same spacecraft in the navigation constellation establishes multiple links at the same time to obtain optical axis pointing error measurement data in different directions. By simultaneously estimating the spacecraft attitude measurement error and the optical axis pointing's own pointing error parameters, the separation of the spacecraft attitude measurement error and the optical axis pointing's own pointing error is achieved. This paper mainly analyzes the impact of the satellite platform attitude error on the laser terminal optical axis pointing, and does not involve the processing of non-orthogonality of the two-dimensional turntable.

[0004] In the paper "Laser Communication LoS Pointing Technology Based on Kalman Filter" (Wireless Optical Communication, Issue 9, 2018), it is proposed to use the ground fixed-point laser communication system as the background, obtain the initial pointing angle through the coordinate transformation matrix, analyze the factors affecting the accuracy error of the loS Pointing Angle, introduce the Kalman filter technology into the loS Pointing system, and complete the system modeling. This paper treats the optical communication loS Pointing as a comprehensive system error and does not involve the non-orthogonal processing of the two-dimensional turntable.

[0005] In the paper "Method for Measuring the Axis Accuracy of Coarse Pointing Mechanisms in Laser Communication" (Special Column of the Assembly Process Technology Center Exchange Meeting of China Aerospace Science and Technology Corporation, Issue 1, 2020), the process difficulties of measuring the inclination rotation error and verticality of the axis system at the arc second level are introduced. Combined with the test examples, the measurement principle, configuration method and data processing process of the mechanism axis system accuracy measurement are introduced. This paper focuses on the assembly process assurance method for the high-precision verticality of the two-dimensional turntable, and does not involve the analysis and identification and correction of the non-orthogonality of the two-dimensional turntable.

[0006] In the paper "The Influence of Rotating Bi-prism System Errors on Pointing Accuracy in Laser Communication" (Optical Precision Engineering, Issue 6, 2021), the error sources in the rotating bi-prism system are analyzed. According to the error sources, the light beam pointing model is established using the light vector propagation method. Based on the beam pointing model, the partial derivative of the pointing deviation of the output beam of the rotating bi-prism system to the system error is calculated; in the pointing area, the influence of the error on the pointing accuracy is analyzed according to the measurement accuracy of each error. This paper focuses on the influence of the rotating bi-prism on the pointing of the optical axis of the laser terminal, and does not involve the non-orthogonality problem of the two-dimensional turntable.

[0007] In the paper "Study on the Influence of Pointing Accuracy on the Performance of Intersatellite Laser Communication Terminals" (Master's thesis of University of Chinese Academy of Sciences, 2021), the influence of pointing error on the capture process during the establishment of the optical communication link was studied. The satellite attitude was obtained using star sensors, and the error model of the relay optical path branch was established. The relationship between the pointing error and the two-axis rotation angle was analyzed, and the influence of the pointing error on the capture probability and the average capture time was studied. This paper also equates the optical axis pointing error of the laser terminal to the system deviation of the star sensor / satellite platform, and does not involve the non-orthogonality problem of the two-dimensional turntable.

[0008] In summary, the non-orthogonality analysis and correction method of the laser terminal two-dimensional turntable proposed in the present invention can adapt to correction under a large range of rotation. Compared with the traditional linear fitting method, it fundamentally solves the influence of non-orthogonality and has higher implementation accuracy. Summary of the invention

[0009] In view of the defects in the prior art, the purpose of the present invention is to provide a method and system for non-orthogonal analysis and correction of a two-dimensional turntable of a laser terminal.

[0010] The non-orthogonality analysis and correction method of the laser terminal two-dimensional turntable provided by the present invention includes:

[0011] Step S1: Establishing a reference coordinate system of the two-dimensional turntable of the laser terminal to describe the rotation mode of the two-dimensional turntable of the laser terminal;

[0012] Step S2: using the geometric transfer method to establish an optical axis pointing transfer model that does not contain non-orthogonal errors;

[0013] Step S3: adding a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model containing non-orthogonal errors;

[0014] Step S4: Drive the two-dimensional turntable to point to different angles, establish equivalent equations on-orbit using geometric calibration points, solve the equivalent non-orthogonal deviation angle parameters and bring them into the optical axis pointing transfer model containing non-orthogonal errors, thereby eliminating the influence of non-orthogonality on the optical axis pointing error.

[0015] Preferably, the step S1 comprises:

[0016] First, define the pitch axis reference coordinate system, the origin of the coordinate system is O f Located at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The axis forms a right-hand rectangular coordinate system; according to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y f Axis rotation;

[0017] Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z c The axis forms a right-hand rectangular coordinate system; according to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c Axis rotation;

[0018] Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located in the lower right corner of the mounting surface; when the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

[0019] Preferably, step S2 comprises:

[0020] First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows:

[0021]

[0022] Then, considering the influence of the azimuth axis rotation on the pointing direction of the laser terminal optical axis, the optical terminal optical axis vector is projected to the two-dimensional turntable axis reference coordinate system. The expression is as follows:

[0023]

[0024] Combining the two equations, we get:

[0025]

[0026] In the formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

[0027] Preferably, step S3 comprises:

[0028] The expression of the optical axis pointing transfer model containing non-orthogonal errors is:

[0029]

[0030] In the formula, R f is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows:

[0031]

[0032] Where, X f is the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis; f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis;

[0033] R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows:

[0034]

[0035] Where, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis; c , Y c , Zc are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

[0036] Preferably, the step S4 comprises:

[0037] The optical axis pointing transfer model with non-orthogonal error is simplified as:

[0038]

[0039] In the formula, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Z c is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis;

[0040] N x (α) is the azimuth axis transfer matrix, which is expressed as:

[0041]

[0042] N y (β) is the azimuth axis transfer matrix, which is expressed as:

[0043]

[0044] The simplified equivalent non-orthogonal deviation angle parameters are solved and brought into the optical axis pointing transfer model containing non-orthogonal errors to eliminate the influence of non-orthogonality on the optical axis pointing error.

[0045] The laser terminal two-dimensional turntable non-orthogonal analysis and correction system provided by the present invention comprises:

[0046] Module M1: Establish the reference coordinate system of the two-dimensional turntable of the laser terminal and describe the rotation mode of the two-dimensional turntable of the laser terminal;

[0047] Module M2: Use geometric transfer method to establish an optical axis pointing transfer model without non-orthogonal errors;

[0048] Module M3: Add a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model with non-orthogonal errors;

[0049] Module M4: Drive the two-dimensional turntable to point to different angles, establish equivalent equations using geometric calibration points on-orbit, solve the equivalent non-orthogonal deviation angle parameters and bring them into the optical axis pointing transfer model containing non-orthogonal errors, thereby eliminating the influence of non-orthogonality on the optical axis pointing error.

[0050] Preferably, the module M1 comprises:

[0051] First, define the pitch axis reference coordinate system, the origin of the coordinate system is O fLocated at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The axis forms a right-hand rectangular coordinate system; according to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y f Axis rotation;

[0052] Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z c The axis forms a right-hand rectangular coordinate system; according to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c Axis rotation;

[0053] Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located in the lower right corner of the mounting surface; when the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

[0054] Preferably, the module M2 comprises:

[0055] First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows:

[0056]

[0057] Then, considering the influence of the azimuth axis rotation on the pointing direction of the laser terminal optical axis, the optical terminal optical axis vector is projected to the two-dimensional turntable axis reference coordinate system. The expression is as follows:

[0058]

[0059] Combining the two equations, we get:

[0060]

[0061] In the formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

[0062] Preferably, the module M3 comprises:

[0063] The expression of the optical axis pointing transfer model containing non-orthogonal errors is:

[0064]

[0065] In the formula, R f is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows:

[0066]

[0067] Where, X f is the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis; f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis;

[0068] R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows:

[0069]

[0070] Where, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis; c , Y c , Z c are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

[0071] Preferably, the module M4 comprises:

[0072] The optical axis pointing transfer model with non-orthogonal error is simplified as:

[0073]

[0074] Where, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Zc is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis;

[0075] N x (α) is the azimuth axis transfer matrix, which is expressed as:

[0076]

[0077] N y (β) is the azimuth axis transfer matrix, which is expressed as:

[0078]

[0079] The simplified equivalent non-orthogonal deviation angle parameters are solved and brought into the optical axis pointing transfer model containing non-orthogonal errors to eliminate the influence of non-orthogonality on the optical axis pointing error.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] The present invention proposes a non-orthogonality analysis and correction method for a two-dimensional turntable of a laser terminal. Through geometric modeling, the influence of the non-orthogonality of the two-dimensional turntable on the pointing of the optical axis is analyzed, and a non-orthogonality solution method is proposed. The method can adapt to correction under a large range of rotation. Compared with the traditional linear fitting method, it fundamentally solves the influence of non-orthogonality and has higher implementation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0083] Figure 1 It is a schematic diagram of the definition of the two-dimensional turntable coordinate system of the laser terminal;

[0084] Figure 2 is the relationship between the optical axis pointing error and the pitch axis rotation angle (azimuth axis zero position);

[0085] Figure 3 is the relationship between the optical axis pointing error and the pitch axis rotation angle (the azimuth axis is offset by 30°);

[0086] Figure 4 It is the optical axis pointing error (azimuth axis zero position) after non-orthogonal correction;

[0087] Figure 5 It is the optical axis pointing error after non-orthogonal correction (azimuth axis offset 30°). DETAILED DESCRIPTION

[0088] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0089] Example 1

[0090] The present invention provides a non-orthogonal analysis and correction method for a two-dimensional turntable of a laser terminal, comprising the following steps:

[0091] Step S1: Establish a two-dimensional turntable reference coordinate system to describe the rotation mode of the two-dimensional turntable;

[0092] Step S2: using the geometric transfer method to establish an optical axis pointing transfer model that does not contain non-orthogonal errors;

[0093] Step S3: adding a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model containing non-orthogonal errors;

[0094] Step S4: Establish a calibration method based on the optical axis pointing transfer model containing non-orthogonal errors to achieve nonlinear correction under a wide range of rotation angles.

[0095] The step S1 comprises:

[0096] like Figure 1 First, define the pitch axis reference coordinate system, the origin of the coordinate system is O f Located at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The Y axis forms a right-hand rectangular coordinate system. According to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y axis. f The shaft rotates.

[0097] Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z c The axes form a right-hand rectangular coordinate system. According to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c The shaft rotates.

[0098] Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located at the lower right corner of the mounting surface. When the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

[0099] The step S2 comprises:

[0100] First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows:

[0101]

[0102] In the above formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle.

[0103] Next, consider the influence of the azimuth axis rotation on the optical axis pointing of the laser terminal and project the optical axis vector of the optical terminal to the two-dimensional turntable axis reference coordinate system. The expression is as follows:

[0104]

[0105] In the above formula, is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

[0106] Combining the above formulas, we get:

[0107]

[0108] In the above formula, α is the azimuth axis angle, β is the elevation axis angle, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system, is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system.

[0109] The step S3 comprises:

[0110] The expression of the optical axis pointing transfer model containing non-orthogonal errors is:

[0111]

[0112] In the above formula, Rf is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows:

[0113]

[0114] In the above formula, X f is the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis.

[0115] X f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis.

[0116] R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows:

[0117]

[0118] In the above formula, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis.

[0119] X c , Y c , Z c are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

[0120] According to the optical axis pointing transfer model of non-orthogonal error, affected by the non-orthogonality of the rotation axis, when the two-dimensional rotation angle is rotated to different positions, the corresponding optical axis pointing errors are inconsistent, and the pitch axis and azimuth axis of the two-dimensional turntable are coupled with each other, and the rotation angle of the azimuth axis also affects the non-orthogonality of the pitch axis.

[0121] A set of non-orthogonal parameters is randomly generated. When the azimuth angle is at zero, the relationship between the laser terminal optical axis pointing error and the pitch axis can be obtained as shown in the attached figure. Figure 2 As shown in the figure, the optical axis pointing error changes with the change of the pitch axis. When the azimuth offset is 30°, the relationship between the laser terminal optical axis pointing error and the pitch axis can be obtained as shown in the figure below: Figure 3 As shown, the variation patterns of the optical axis pointing error and the pitch axis rotation angle are inconsistent with the variation patterns when the azimuth angle is at zero, indicating that the non-orthogonality of the pitch axis and the azimuth axis has the feature of mutual coupling.

[0122] The step 4 comprises:

[0123] Step 3 introduces the optical axis pointing transfer model with non-orthogonal errors. The model contains 6 equivalent non-orthogonal deviation angle parameters (3 in azimuth and 3 in elevation). To facilitate model correction, the equivalent non-orthogonal deviation angle parameters can be optimized according to the physical meaning of the rotation axis.

[0124] According to the coordinate system definition, the rotation axis of the pitch axis is the same as the Y axis of the pitch axis reference coordinate system. f The axes are parallel, so the non-orthogonal rotation error of the pitch axis relative to the Y axis will not cause non-orthogonal changes in the direction of the optical axis; similarly, the rotation axis of the azimuth axis is parallel to the X axis of the azimuth axis reference coordinate system. c The axes are parallel, so the non-orthogonal rotation error of the azimuth axis relative to the X-axis will not cause non-orthogonal changes in the optical axis pointing. Based on the above analysis, the optical axis pointing transfer model containing non-orthogonal errors can be simplified as:

[0125]

[0126] In the above formula, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Z c is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis.

[0127] N x (α) is the azimuth axis transfer matrix, which is expressed as:

[0128]

[0129] N y (β) is the azimuth axis transfer matrix, which is expressed as:

[0130]

[0131] In order to correct the influence of non-orthogonal parameters on the pointing of the laser terminal, it is necessary to solve the simplified equivalent non-orthogonal deviation angle parameters. Under the influence of non-orthogonality, the optical axis pointing deviations corresponding to different rotation angles are different. Therefore, when solving the problem, it is necessary to drive the two-dimensional turntable to point to different angles, and use geometric calibration points such as stars and landmarks on orbit to establish equivalent equations to solve non-orthogonal parameters.

[0132] Finally, the four simplified equivalent non-orthogonal deviation angle parameters are brought into the optical axis pointing transfer model to eliminate the influence of non-orthogonality on the optical axis pointing error. Figure 4 The optical axis pointing error when the azimuth axis is at zero position after non-orthogonal correction is given. Figure 5 The optical axis pointing error after non-orthogonal correction when the azimuth axis is offset by 30° is given. From the calculation results, it can be seen that the optical axis pointing error after non-orthogonal correction is significantly reduced, indicating that the present invention is effective.

[0133] Example 2

[0134] The present invention also provides a laser terminal two-dimensional turntable non-orthogonal analysis and correction system, which can be implemented by executing the process steps of the laser terminal two-dimensional turntable non-orthogonal analysis and correction method, that is, technical personnel in this field can understand the laser terminal two-dimensional turntable non-orthogonal analysis and correction method as a preferred implementation of the laser terminal two-dimensional turntable non-orthogonal analysis and correction system.

[0135] The laser terminal two-dimensional turntable non-orthogonal analysis and correction system provided by the present invention comprises:

[0136] Module M1: Establish the reference coordinate system of the two-dimensional turntable of the laser terminal and describe the rotation mode of the two-dimensional turntable of the laser terminal;

[0137] Module M2: Use geometric transfer method to establish an optical axis pointing transfer model without non-orthogonal errors;

[0138] Module M3: Add a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model with non-orthogonal errors;

[0139] Module M4: Drive the two-dimensional turntable to point to different angles, establish equivalent equations using geometric calibration points on-orbit, solve the equivalent non-orthogonal deviation angle parameters and bring them into the optical axis pointing transfer model containing non-orthogonal errors, thereby eliminating the influence of non-orthogonality on the optical axis pointing error.

[0140] The module M1 comprises:

[0141] First, define the pitch axis reference coordinate system, the origin of the coordinate system is O f Located at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The axis forms a right-hand rectangular coordinate system; according to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y f Axis rotation;

[0142] Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z cThe axis forms a right-hand rectangular coordinate system; according to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c Axis rotation;

[0143] Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located in the lower right corner of the mounting surface; when the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

[0144] The module M2 comprises:

[0145] First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows:

[0146]

[0147] Then, considering the influence of the azimuth axis rotation on the pointing direction of the laser terminal optical axis, the optical terminal optical axis vector is projected to the two-dimensional turntable axis reference coordinate system. The expression is as follows:

[0148]

[0149] Combining the two equations, we get:

[0150]

[0151] In the formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

[0152] The module M3 comprises:

[0153] The expression of the optical axis pointing transfer model containing non-orthogonal errors is:

[0154]

[0155] In the formula, R f is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows:

[0156]

[0157] In the formula, X fis the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis; f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis;

[0158] R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows:

[0159]

[0160] Where, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis; c , Y c , Z c are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

[0161] The module M4 comprises:

[0162] The optical axis pointing transfer model with non-orthogonal error is simplified as:

[0163]

[0164] Where, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Z c is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis;

[0165] N x (α) is the azimuth axis transfer matrix, which is expressed as:

[0166]

[0167] N y (β) is the azimuth axis transfer matrix, which is expressed as:

[0168]

[0169] The simplified equivalent non-orthogonal deviation angle parameters are solved and brought into the optical axis pointing transfer model containing non-orthogonal errors to eliminate the influence of non-orthogonality on the optical axis pointing error.

[0170] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0171] The above describes the specific embodiments of the present invention. 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 does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for non-orthogonal analysis and correction of a two-dimensional turntable of a laser terminal, characterized in that: include: Step S1: Establishing a reference coordinate system of the two-dimensional turntable of the laser terminal to describe the rotation mode of the two-dimensional turntable of the laser terminal; Step S2: using the geometric transfer method to establish an optical axis pointing transfer model that does not contain non-orthogonal errors; Step S3: adding a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model containing non-orthogonal errors; Step S4: Drive the two-dimensional turntable to point to different angles, establish equivalent equations on-orbit using geometric calibration points, solve the equivalent non-orthogonal deviation angle parameters and bring them into the optical axis pointing transfer model containing non-orthogonal errors, thereby eliminating the influence of non-orthogonality on the optical axis pointing error.

2. The non-orthogonal analysis and correction method of the laser terminal two-dimensional turntable according to claim 1 is characterized in that: The step S1 comprises: First, define the pitch axis reference coordinate system, the origin of the coordinate system is O f Located at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The axis forms a right-hand rectangular coordinate system; according to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y f Axis rotation; Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z c The axis forms a right-hand rectangular coordinate system; according to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c Axis rotation; Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located in the lower right corner of the mounting surface; when the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

3. The non-orthogonal analysis and correction method for a two-dimensional laser terminal turntable according to claim 2 is characterized in that: The step S2 comprises: First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows: Then, considering the influence of the azimuth axis rotation on the pointing direction of the laser terminal optical axis, the optical terminal optical axis vector is projected to the two-dimensional turntable axis reference coordinate system. The expression is as follows: Combining the two equations, we get: In the formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

4. The non-orthogonal analysis and correction method for a two-dimensional laser terminal turntable according to claim 3 is characterized in that: The step S3 comprises: The expression of the optical axis pointing transfer model containing non-orthogonal errors is: Where R is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows: Where, X f is the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis; f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis; R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows: Where, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis; c , Y c , Z c are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

5. The non-orthogonal analysis and correction method for a two-dimensional laser terminal turntable according to claim 4 is characterized in that: The step S4 comprises: The optical axis pointing transfer model with non-orthogonal error is simplified as: Where, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Z c is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis; Nx(α) is the azimuth axis transfer matrix, expressed as: N y (β) is the azimuth axis transfer matrix, which is expressed as: The simplified equivalent non-orthogonal deviation angle parameters are solved and brought into the optical axis pointing transfer model containing non-orthogonal errors to eliminate the influence of non-orthogonality on the optical axis pointing error.

6. A laser terminal two-dimensional turntable non-orthogonal analysis and correction system, characterized in that: include: Module M1: Establish the reference coordinate system of the two-dimensional turntable of the laser terminal and describe the rotation mode of the two-dimensional turntable of the laser terminal; Module M2: Use geometric transfer method to establish an optical axis pointing transfer model without non-orthogonal errors; Module M3: Add a non-orthogonal error transfer matrix to the optical axis pointing transfer model to establish an optical axis pointing transfer model with non-orthogonal errors; Module M4: Drive the two-dimensional turntable to point to different angles, establish equivalent equations using geometric calibration points on-orbit, solve the equivalent non-orthogonal deviation angle parameters and bring them into the optical axis pointing transfer model containing non-orthogonal errors, thereby eliminating the influence of non-orthogonality on the optical axis pointing error.

7. The laser terminal two-dimensional turntable non-orthogonal analysis and correction system according to claim 6 is characterized in that: The module M1 comprises: First, define the pitch axis reference coordinate system, the origin of the coordinate system is O f Located at the center of the pitch axis, +Z f The axis is perpendicular to the turntable mounting surface and parallel to the direction of the optical axis of the laser terminal; +Y f The axis is parallel to the pitch axis; X f Axis and Y f Axis and Z f The axis forms a right-hand rectangular coordinate system; according to the definition of the pitch axis reference coordinate system, the pitch mechanism revolves around the Y f Axis rotation; Then define the azimuth axis reference coordinate system, the origin of the coordinate system is O c Located at the center of the mounting area between the azimuth axis and the mounting surface, +X c The axis is parallel to the azimuth axis; when the azimuth axis is at zero position, +Y c The axis is parallel to the pitch axis; X c Axis and Y c Axis and Z c The axis forms a right-hand rectangular coordinate system; according to the definition of the azimuth axis reference coordinate system, the azimuth mechanism revolves around the X c Axis rotation; Finally, define the two-dimensional turntable reference coordinate system, the origin of the coordinate system O b Located in the lower right corner of the mounting surface; when the azimuth axis is at zero position, the X b Axis, Y b Axis, Z b Axis and azimuth axis of the reference coordinate system X c Axis, Y c Axis, Z c Axis parallel.

8. The laser terminal two-dimensional turntable non-orthogonal analysis and correction system according to claim 7 is characterized in that: The module M2 comprises: First, the influence of the pitch axis on the pointing direction of the laser terminal optical axis is analyzed, and the laser terminal optical axis vector is projected to the azimuth axis reference coordinate system. The expression is as follows: Then, considering the influence of the azimuth axis rotation on the pointing direction of the laser terminal optical axis, the optical terminal optical axis vector is projected to the two-dimensional turntable axis reference coordinate system. The expression is as follows: Combining the two equations, we get: In the formula, is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; is the projection of the laser terminal optical axis vector in the azimuth axis reference coordinate system; β is the pitch axis rotation angle; is the projection of the laser terminal optical axis vector in the pitch axis reference coordinate system; α is the azimuth axis rotation angle.

9. The laser terminal two-dimensional turntable non-orthogonal analysis and correction system according to claim 8, characterized in that: The module M3 comprises: The expression of the optical axis pointing transfer model containing non-orthogonal errors is: In the formula, R f is the non-orthogonal transfer matrix of the pitch axis, and its expression is as follows: Where, X f is the non-orthogonal rotation error of the pitch axis relative to the X axis, f is the non-orthogonal rotation error of the pitch axis relative to the Y axis, Z f is the non-orthogonal rotation error of the pitch axis relative to the Z axis; f , Y f , Z f are the three equivalent non-orthogonal deviation angle parameters of the pitch axis; R c is the azimuth axis non-orthogonal transfer matrix, expressed as follows: Where, X c is the non-orthogonal rotation error of the azimuth axis relative to the X axis, Y c is the non-orthogonal rotation error of the azimuth axis relative to the Y axis, Z c is the non-orthogonal rotation error of the azimuth axis relative to the Z axis; c , Y c , Z c are the three equivalent non-orthogonal deviation angle parameters of the azimuth axis.

10. The laser terminal two-dimensional turntable non-orthogonal analysis and correction system according to claim 9, characterized in that: The module M4 comprises: The optical axis pointing transfer model with non-orthogonal error is simplified as: Where, X f , Z f is the simplified equivalent non-orthogonal deviation angle parameter of the pitch axis, Y c , Z c is the simplified equivalent non-orthogonal deviation angle parameter of the azimuth axis; N x (α) is the azimuth axis transfer matrix, which is expressed as: N y (β) is the azimuth axis transfer matrix, which is expressed as: The simplified equivalent non-orthogonal deviation angle parameters are solved and brought into the optical axis pointing transfer model containing non-orthogonal errors to eliminate the influence of non-orthogonality on the optical axis pointing error.

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