A dynamic light machine coupling light ray tracing method

Abstract

The application discloses a dynamic light-mechanical coupling light ray tracing method, solves the problems of low technical efficiency of micro-vibration light-mechanical integration analysis of a space optical remote sensor and the problem of not comprehensively considering the elastic deformation of optical element mirror surfaces, and comprises the following steps: firstly, finite element modeling is performed on an optical system of the space optical remote sensor, micro-vibration is applied as input, structural dynamic responses of each component of the optical system under the micro-vibration are obtained, and node displacements of optical surfaces of interest are obtained; then, an interpolation method is used to reconstruct smooth optical surfaces based on the node displacements; a light-mechanical coupling light ray tracing model is established; and finally, dynamic light ray tracing is performed on the space optical remote sensor based on the light-mechanical coupling light ray tracing model, and a dynamic wavefront difference of the space optical remote sensor is obtained. The application combines multiple analysis methods to realize dynamic analysis of the optical system of the space optical remote sensor, realizes the analysis of the integration of the light-mechanical system through the light-mechanical coupling, and realizes dynamic and efficient analysis of the influence of the micro-vibration on the imaging quality of the space optical remote sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of optical-mechanical integration analysis of a space optical remote sensor reflection or refraction system, and in particular to a dynamic optical-mechanical coupling ray tracing method. Background Art

[0002] With the continuous development and progress of my country's space industry, space optical cameras are trending towards larger apertures, wider fields of view, higher resolution, and lighter weight. Currently, the ground pixel resolution of space optical cameras has reached the sub-meter level. High-precision and high-quality optical cameras place increasing demands on the overall optical axis pointing stability and image quality of the platform and optical system during on-orbit imaging. As the focal length and aperture of optical systems continue to increase, the rigidity of the optomechanical system is limited by mass, making it increasingly sensitive to micro-vibrations caused by the normal operation of onboard moving components. Micro-vibrations can affect the on-orbit imaging quality of space optical cameras. This is especially true for large-aperture, long-focal-length, reflective optical systems, whose structures have high specific stiffness but low absolute stiffness. This leads to a sharp increase in the sensitivity of the optomechanical structure to mechanical and thermal loads. After a satellite is launched into orbit, disturbances such as the platform's moving components act on the satellite structure and are transmitted to the remote sensing sensor, causing micro-vibrations in the optical system in inertial space. Regardless of the imaging method used (including area array staring, linear array push scanning, etc.), micro-vibration will cause disturbances in the optical axis and internal optical elements of the optical system, resulting in a decrease in the system's Modulation Transfer Function (MTF) and image quality degradation, which greatly restricts the system's imaging quality.

[0003] The current main approach to studying microvibrations in space-based optical cameras is to treat the camera and the entire satellite structure as elastic bodies, thereby simplifying the problem to the dynamics of the entire satellite structure. However, this simplification also has certain drawbacks: simplifying the optical camera to a single mass point or multiple rigidly coupled mass points ignores the impact of structural microvibrations of the sensor's internal optical components on imaging quality; and it fails to comprehensively consider the impact of the combined elastic deformation of all optical components on the dynamic wavefront error (optical system imaging quality) of the entire system, resulting in low efficiency and limited effectiveness. Currently, there is no effective optomechanical coupled ray tracing method that can efficiently analyze the impact of microvibrations on the imaging quality of space-based optical remote sensors. Summary of the Invention

[0004] The purpose of the present invention is to provide a dynamic optomechanical coupling ray tracing method that can solve the problems of low efficiency, insignificant effect and inability to comprehensively consider the influence of the elastic deformation of the mirror surfaces of all superimposed optical elements on the imaging quality of the optical system in the micro-vibration optomechanical integrated analysis technology of space optical remote sensors.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A dynamic optomechanical coupling ray tracing method comprises the following steps:

[0007] Step 1: Use finite element analysis software to perform finite element modeling of the optical system of the space optical remote sensor. Apply micro-vibration as the input of the structural finite element model to obtain the structural dynamic response of each component of the optical system under the action of micro-vibration. Then, process the structural dynamic analysis results to obtain the nodal displacement of the optical surface of interest.

[0008] Step 2: Based on the node displacement of the optical surface of interest obtained in step 1, the smooth optical surface is reconstructed using interpolation method and least square method;

[0009] Step 3: Establish an optomechanical coupling ray tracing model;

[0010] Step 4: Perform dynamic ray tracing on the space optical remote sensor based on the optomechanical coupling ray tracing model to obtain the dynamic wavefront difference of the space optical remote sensor.

[0011] The present invention addresses the multidisciplinary nature of the impact of micro-vibrations on the optical system of a space optical remote sensor, combines multiple analysis methods to achieve dynamic analysis of the optical system of a space optical remote sensor, and realizes integrated analysis of the optical-mechanical system through opto-mechanical coupling. This is a very effective opto-mechanical integrated analysis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by the present invention.

[0013] Figure 1 A schematic flow chart of a dynamic optomechanical coupling ray tracing method according to the present invention;

[0014] Figure 2 Schematic diagram of a single ray tracing in an embodiment of the present invention;

[0015] Figure 3 Schematic diagram of an optomechanical coupling ray tracing model in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The optical system and mechanical system in current space optical remote sensors are often analyzed independently of each other. However, the dynamic optomechanical coupling ray tracing method provided by the present invention can couple the optics and structure together to realize performance analysis of the optomechanical system, and perform dynamic and efficient analysis of the impact of micro-vibration on the imaging quality of the space optical remote sensor. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] In one embodiment, Figure 1 As shown, the present invention provides a dynamic optomechanical coupling ray tracing method, which includes the following steps:

[0018] Step 1: Obtain the overall position relationship and surface elastic deformation of the optical system through structural dynamics analysis.

[0019] Finite element modeling of the optical system is performed using finite element analysis software (such as Hypermesh and MSC Patran) to establish a structural finite element model. Micro-vibration is applied as the input of the structural finite element model to obtain the structural dynamic responses of each component of the optical system under the action of micro-vibration, that is, to obtain the structural dynamic analysis results. The structural dynamic analysis results are then processed to finally obtain the node displacements of the optical surface of interest.

[0020] Step 2: Reconstruct the deformed optical surface.

[0021] Based on the node displacements of the optical surface of interest obtained through the structural dynamics analysis in step one, a suitable interpolation method, such as the cubic spline interpolation method, is selected to interpolate the node displacements to complete the node displacement approximation, and the least squares method is used to fit the interpolated and reconstructed smooth optical surface.

[0022] Step 3: Establish an optomechanical coupling ray tracing model.

[0023] First of all, whether the light is refracted or reflected on the optical surface, the focus should be on the intersection of the light and the optical surface and the corresponding direction of the light. Figure 2 As shown in Figure 1, the optomechanical coupled ray tracing model is based on linear algebra and geometric optics to calculate the path of a single ray in an optical system. The order in which the ray passes through the optical surface is determined in advance, and then the corresponding reference frame S is used to calculate the path of a single ray in the optical system. i-1 The intersection point m of the ray at the i-1th optical surface (surface i-1) is considered. i-1 and the associated ray direction d i-1The relative position S i and the relative direction R i of the next optical surface (surface i) reference system are given i-1 The intersection point of the light ray and the direction of the light ray must be transformed from the reference system S i to the reference system S Figure 2 m i is the intersection point of the light ray at the i-th optical surface (surface i), d i is the refracted light ray direction, d i,refl is the reflected light ray direction, r i-1 is the vector from the reference system S i to the intersection point of the light ray m i-1 , and r i is the vector from the reference system S i to the intersection point of the light ray m i . According to the vector r i-1 and the direction of the light ray d i-1 , the intersection point m i of the light ray at the i-th optical surface can be obtained, and the direction of the light ray after refraction or reflection can be obtained according to the relative direction R i .

[0024] Then, based on the structure finite element model of the optical system, the relevant nodes are extracted in the single light ray tracing process, the optical path under the reconstructed smooth optical surface is calculated through the smooth optical surface reconstructed by step two interpolation, and the calculated optical path is compared with the optical path of the ideal light path to obtain the optical path difference of the single light ray.

[0025] Finally, as shown in Figure 3 , large-scale light ray tracing is performed to comprehensively obtain the wavefront difference of the entire light beam or main light beam, so as to realize the "optical-structure" coupling.

[0026] Step four: based on the light-mechanical coupling light ray tracing model constructed in step three, dynamic light ray tracing is performed on the space optical remote sensor to obtain the dynamic wavefront difference of the space optical remote sensor, so as to analyze the influence of micro-vibration on the imaging quality of the space optical remote sensor.

[0027] The dynamic optomechanical coupling ray tracing method proposed in this embodiment uses finite element analysis software to perform structural dynamics analysis on the optical structure of a space optical remote sensor. The node displacements of the optical surface of interest are obtained from the analysis results, and an appropriate interpolation method is selected to interpolate and reconstruct a smooth optical surface. The wavefront characteristics of the ideal optical path are given based on the ideal adjustment relationship of the optical system and the geometric surface of the mirror. Then, using the structural finite element model of the reflector, the relevant nodes are extracted during the single ray tracing process, and a smooth optical surface is reconstructed by interpolation. The optical path under the reconstructed surface is calculated and compared with the ideal optical path to obtain the optical path difference of the single light beam. Finally, large-scale ray tracing is performed to comprehensively obtain the wavefront difference of the entire light beam (or main beam), realize optomechanical coupling, and perform dynamic optomechanical coupling ray tracing on the space optical remote sensor. Based on this method, better and more efficient analysis of the impact on the imaging quality of space optical remote sensors can be performed.

[0028] This embodiment addresses the multidisciplinary nature of the impact of micro-vibrations on the optical system of a space optical remote sensor, combines multiple analysis methods to achieve dynamic analysis of the optical system of a space optical remote sensor, and implements integrated analysis of the optical-mechanical system through opto-mechanical coupling. This is a very effective opto-mechanical integration analysis method.

[0029] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0030] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A dynamic optomechanical coupling ray tracing method, characterized in that: The following steps are involved: Step 1: Use finite element analysis software to perform finite element modeling of the optical system of the space optical remote sensor. Apply micro-vibration as the input of the structural finite element model to obtain the structural dynamic response of each component of the optical system under the action of micro-vibration. Then, process the structural dynamic analysis results to obtain the nodal displacement of the optical surface of interest. Step 2: Based on the node displacement of the optical surface of interest obtained in step 1, the smooth optical surface is reconstructed using the interpolation method and the least squares method; Step 3: Establish an optical-mechanical coupling ray tracing model; Step 4: Perform dynamic ray tracing on the space optical remote sensor based on the optomechanical coupling ray tracing model to obtain the dynamic wavefront difference of the space optical remote sensor.

2. A dynamic optomechanical coupling ray tracing method according to claim 1, characterized in that: The optomechanical coupling ray tracing model performs the following steps: Step 31: Calculate the path of a single ray in the optical system; Step 32: Based on the structural finite element model of the optical system, extract relevant nodes during the single ray tracing process, calculate the optical path under the smooth optical surface reconstructed in step 2, and compare the calculated optical path with the optical path of the ideal optical path to obtain the optical path difference of the single ray; Step 33: Perform large-scale ray tracing to comprehensively obtain the wavefront difference of the entire beam or main beam coupled by the optomechanical mechanism.

3. A dynamic optomechanical coupling ray tracing method according to claim 1 or 2, characterized in that: The finite element analysis software is Hypermesh software or MSC Patran software.

4. A dynamic optomechanical coupling ray tracing method according to claim 1 or 2, characterized in that: The interpolation method is a cubic spline interpolation method.

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