High-precision high-stability large-aperture dual-camera common special-shaped primary mirror

Abstract

The invention discloses a high-precision high-stability large-aperture dual-camera common special-shaped primary mirror which comprises a dual-primary mirror body and a primary mirror support. The double-primary mirror body is a combined body of two coaxial single primary mirrors which are in mirror symmetry; and the primary mirror support is used for realizing quasi-static support of the double-primary mirror body. The common primary mirror adopts an integrated structure form, so that the scale of an optical machine can be reduced, the specific stiffness of the whole machine is improved, the structural precision and stability are improved, and the common primary mirror has wide application prospects in the field of three-dimensional surveying and mapping viewing angles.

Description

Technical Field

[0001] The invention relates to a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, belonging to the technical field of space optical remote sensors. Background Art

[0002] With the improvement of remote sensor research and development level and the gradual improvement of satellite platform design and development level, optical remote sensing satellites at home and abroad have made great progress in recent years. Space optical remote sensing systems have also become increasingly complex, developing towards higher spatial resolution, spectral resolution and radiation resolution.

[0003] Stereo mapping is the process of drawing a topographic map of a certain scale based on the stereo images formed by two different camera stations shooting the same ground scene from different angles under the same orbital conditions. With the continuous improvement of the mapping scale, it is inevitable to ensure the accuracy of the position information of the acquired stereo images to achieve refined mapping tasks, that is, it is necessary to ensure the plane positioning accuracy that represents the accuracy of the plane position information, and it is also necessary to ensure the elevation positioning accuracy that represents the accuracy of the height position information. According to the specific working method of the camera to achieve stereo mapping perspective, mapping cameras can be divided into three types: single-line array stereo mapping cameras, dual-line array stereo mapping cameras, and three-line array stereo mapping cameras. Single-line array stereo mapping cameras require satellite platforms to maneuver quickly to complete the stereo mapping process. Under uncontrolled conditions, the elevation positioning accuracy of their stereo images cannot meet the accuracy requirements of larger scale mapping. Three-line array stereo mapping cameras can achieve higher positioning accuracy, but they need to be configured with three cameras for front view, front view, and rear view. They are large in size and weight and are basically not suitable for agile mapping. The dual-line array stereo mapping camera can achieve long-strip mapping through dual-line array push scanning, improve mapping efficiency, and has improved positioning accuracy compared to the single-line array mapping camera.

[0004] At present, in order to meet the needs of high-resolution and wide-width detection, typical dual-line array stereo mapping cameras at home and abroad are generally equipped with two independent high-resolution cameras, and the base height ratio is changed by changing the installation angle of the two cameras. Since the elevation accuracy is easy to ensure under the condition of a large base height ratio, the existing dual-line array stereo mapping cameras basically adopt a large base height ratio fixed at 0.6 to 1. The high-resolution dual-line array stereo mapping camera system under this base height ratio condition is large in size and weight, which makes it difficult to perform agile detection in key areas.

[0005] In order to simplify the design difficulty of the dual-camera combined imaging system and unify the installation scheme of the two cameras, the dual cameras generally use exactly the same optomechanical support form, and use the same mounting substrate to achieve the registration and installation of the two cameras. The dual-camera combined imaging mode solves the requirements of high resolution and wide width, but for the entire optomechanical imaging system, the dual-camera mode expands the scale of the whole machine, which is not conducive to compact envelope design and whole-satellite mobile imaging; at the same time, due to the use of the dual-camera design, in large optomechanical structures, especially the processing and inspection of large-aperture reflectors such as the primary mirror, and the whole machine installation process, more error sources and installation variables are introduced, which is not conducive to the rapid convergence of the system installation, as well as the high precision and high stability of the whole machine. Summary of the invention

[0006] The purpose of the present invention is to overcome the above defects and provide a high-precision, high-stability, large-aperture dual-camera common primary mirror, which solves the technical problem that the existing high-resolution dual-line array stereo mapping camera relies on two independent cameras for imaging. The common primary mirror of the present invention adopts an integrated structure, which can reduce the optical and mechanical scale of the dual-line array camera, improve the specific rigidity of the whole machine, and improve the structural accuracy and stability, and has broad application prospects in the field of stereo mapping.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, comprising a dual primary mirror body and a primary mirror support;

[0009] The dual primary mirror body is a combination of two mirror-symmetrical, coaxial single primary mirrors;

[0010] The primary mirror support is used to achieve quasi-static support of the dual primary mirror body.

[0011] Furthermore, the double primary mirror body is a ULE sandwich layer structure, including a reflector panel, an internal sandwich layer and a reflector back plate; the reflector back plate is fixedly connected to the primary mirror support.

[0012] Furthermore, the single primary mirror in the dual primary mirror body has a configuration that is thick in the center and thin at the edges.

[0013] Furthermore, the optical axis angle of the two single primary mirrors in the double primary mirror body is 16° to 20°, the vertices of the two single primary mirrors are 600 to 1000 mm apart, and the aperture of the single primary mirror is 1 to 1.6 m.

[0014] Furthermore, the two single primary mirrors in the double primary mirror body share a reflector back plate, and the reflector back plate provides the same processing, detection, and adjustment reference for the two single primary mirrors.

[0015] Further, the primary mirror support includes a nested adapter, a flexible support rod, and a support base;

[0016] The two ends of the flexible support rod are respectively connected to the nested adapter and the support base; the support base is connected to the main load-bearing structure, the reflector back plate is provided with a reflector nest at the support point, and the nested adapter is used to connect the reflector nest.

[0017] Furthermore, the two primary mirror supports form a group of Bipod structures. The three groups of Bipod structures are distributed in a circle at equal intervals to achieve quasi-static support. The two flexible support rods in each group of Bipod structures are at 90° in space; the two ends of the flexible support rods are flexible links.

[0018] Furthermore, the three sets of Bipod structures include a total of 6 primary mirror supports, forming 6 support points for the primary mirror body, the 6 support points are mirror-symmetrical, four of which are 0.65R away from the center of the single primary mirror, and the remaining two support points are 0.5R away from the center of the single primary mirror;

[0019] R is the radius of the single primary mirror.

[0020] Furthermore, a support reinforcement is provided at the connection between the reflector back plate and the nested adapter.

[0021] Furthermore, the dual main mirror bodies are an integrated structure, and the dual main mirror bodies simultaneously match the optical systems of two cameras.

[0022] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0023] (1) The present invention creatively proposes a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, which can reduce the scale of the optical machine and improve the specific rigidity of the whole machine: the dual-camera system shares a special-shaped primary mirror, and the corresponding primary mirror support and lens support are simplified to an integrated support form, the whole machine envelope is compact, and the scale of the optical machine is greatly reduced;

[0024] (2) The common shaped primary mirror of the present invention can reduce the source of errors and simplify the manufacturing process: the common primary mirror adopts an integrated structure, so that the two primary mirrors in the dual system can achieve a common reference for processing, detection, and adjustment, reducing the source of errors and improving the structural accuracy and stability; in the dual optical system adjustment process, the system adjustment variables are reduced, greatly improving the adjustment efficiency of the dual camera system;

[0025] (3) The present invention provides an optical structure configuration, a supporting method, and specific design parameters of a common-shaped primary mirror, which is beneficial to the optimized design of a high-resolution dual-line array stereo mapping camera. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of a high-precision, high-stability, large-aperture dual-camera common-shaped primary mirror of the present invention;

[0027] Figure 2This is a diagram showing the angle between two support rods in a single set of Bipods with dual primary mirrors of the present invention;

[0028] Figure 3 This is a diagram showing the relationship between the angles of the three groups of Bipods of the present invention;

[0029] Figure 4 This is a diagram of the support points of the dual primary mirror bodies of the present invention;

[0030] Figure 5 Schematic diagram of the structure of the dual primary mirror, wherein Figure (a) is a bottom view and Figure (b) is a cross-sectional view of Figure (a);

[0031] Figure 6 This is a schematic diagram of the ULE sandwich layer structure of the double primary mirror body of the present invention;

[0032] Figure 7 It is a schematic diagram of the structure of a single support rod of the Bipod of the present invention. DETAILED DESCRIPTION

[0033] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0034] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0035] The present invention provides a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror. The special-shaped primary mirror is a combination of two mirror-symmetrical coaxial single primary mirrors, suitable for a dual-camera system, and matches the optical systems of the two cameras at the same time. The relative precision between the primary mirrors is high, and the overall mechanical and thermal stability is high, which solves the problem of relative positioning accuracy within the dual-camera system.

[0036] The dual-camera system contains two sets of coaxial four-mirror optical systems. The main mirrors of the two optical systems are designed in one piece to form a common special-shaped main mirror. The main mirror is realized by an integrated high-lightweight ULE (ultra-low expansion glass) sandwich layer structure. The special-shaped main mirror is supported by an inverted six-rod support, and two rods form a set of Bipods (two-legged brackets), with a total of three groups. Flexible links are designed at both ends of each support rod to ensure high axial stiffness and low lateral stiffness. The configuration of the common special-shaped main mirror, the position of the support point, etc. are comprehensively optimized to effectively improve the surface accuracy of the common main mirror.

[0037] The dual primary mirrors adopt a highly lightweight ULE sandwich structure, that is, the upper and lower panels are sealed with the middle sandwich layer. The sandwich layer adopts hexagonal honeycomb or triangular reinforcement ribs, and local reinforcement ribs are added near the support points to improve the support strength. The entire dual primary mirror body adopts a thick center and thin edges to improve the edge stiffness of the mirror body and ensure the support surface shape. Due to the dual primary mirror configuration, the mirror body is a long strip, so six rod supports are used to improve the support stability. The support point position (the support point position is the distance from the support point to the center of the single primary mirror that is closer) is between 0.5 and 0.65R (R is the radius of a single reflector). The six rod supports are grouped in pairs to form a Bipod, with a total of three groups. The two rods in a single group are at a 90° angle, and the three groups of Bipods are distributed at a 60° angle, forming a quasi-static support form.

[0038] Example:

[0039] The large-aperture dual-camera common special-shaped primary mirror in the present invention is a common primary mirror structure of a certain remote sensing camera. Now, taking the design of the primary mirror of the camera as an example, the specific implementation method of the present invention is described.

[0040] The remote sensing camera is a high-resolution dual-line array stereo mapping camera, consisting of two mirror-symmetrical coaxial four-mirror optical systems. The optical axis angle of the dual optical system main mirror is 16.2°, the distance between the main mirror vertices is 920mm, and the main mirror diameter is 1.5m. Based on the characteristics of the dual optical system, and considering the compact design of the optical-mechanical structure and the simplification of the dual system optical adjustment, the camera adopts a common main mirror design, that is, two main mirrors are combined into one, using an integrated special-shaped main mirror structure.

[0041] Based on the dual-camera common special-shaped primary mirror of the method of the present invention, the implementation method is specifically described:

[0042] The primary mirror is mainly composed of two parts: a dual primary mirror body 1 and a primary mirror support 2;

[0043] The dual primary mirror body 1 includes: a reflector panel 1.1, an internal sandwich layer 1.2, a reflector back plate 1.3, and a support reinforcement 1.4;

[0044] The primary mirror support 2 is composed of six groups of support structures with the same configuration. Each primary mirror support 2 includes a nested adapter 2.1, a flexible support rod 2.2, and a support base 2.3. The six groups of primary mirror supports 2 are grouped in pairs to form a Bipod structure, with a total of three groups. The two rods in a single group are at an angle of 90°, and the angle between the three groups is 60°, forming a Bipod quasi-statically determinate support form.

[0045] like Figure 1 The dual primary mirror assembly consists of a dual primary mirror body 1 and six primary mirror supports 2.

[0046] like Figure 2 , Figure 3The primary mirror support 2 is an inverted six-rod support. The six rods are grouped in pairs to form a Bipod structure, with a total of three groups. The two support rods in the group are spaced at 90 degrees. The three groups of Bipod ( Figure 3 The first Bipod group 3, the first Bipod group 4, and the first Bipod group 5) are 60° apart from each other, thus achieving Bipod quasi-static support of the main mirror body 1.

[0047] like Figure 4 There are a total of six supporting points on the main mirror body 1 in a mirror-symmetrical form. The four first supporting points 6 are located at 0.65R (R is the radius of a single main mirror), and the two second supporting points 7 are located at 0.5R.

[0048] like Figure 5 , Figure 6 The double primary mirror body 1 is a highly lightweight ULE sandwich structure. The reflector (double primary mirror body 1) is composed of two single primary mirrors in mirror symmetry. The reflector consists of a reflector panel 1.1, an internal sandwich layer 1.2, and a reflector back plate 1.3. The double primary mirror body 1 after integration is in the shape of a long runway. In order to improve the specific stiffness of the mirror body and ensure the supporting surface shape of the edge of the reflector, the single primary mirror adopts a wedge-shaped configuration with a thick center and a thin edge. The center thickness of the reflector is 0.15R (R is the radius of the single primary mirror), the size of the reflector back plate is 1.5R×1.3R, and the wedge edge is 23°. At the same time, in order to ensure the local surface shape near the support point, local radial reinforcement ribs 1.4 are added near the support point of the reflector to improve the support strength. The shared reflector back plate 1.3 of the two primary mirrors provides the same processing, inspection, and adjustment benchmark for the two primary mirrors.

[0049] like Figure 7 The primary mirror support 2 includes a nesting adapter 2.1, a flexible support rod 2.2, and a support base 2.3. The nesting adapter 2.1 serves to connect the Bipod and the reflector nesting; the two ends of the flexible support rod 2.2 are flexible links to ensure high axial stiffness and low lateral stiffness; the support base 2.3 serves to connect the dual primary mirror assembly with the main load-bearing structure. Two primary mirror supports 2 form a set of Bipods, and three sets of Bipods achieve quasi-static support.

[0050] The common-shaped main mirror of the present invention weighs 125Kg, a single support weighs 2.2Kg, the total weight of the main mirror assembly is 138Kg, the main mirror optical axis is in a horizontal adjustment state, and the surface shape can reach 1 / 50λ (λ is the light source wavelength of the interferometer of the surface shape detection equipment, 632.8nm).

[0051] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0052] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A high-precision, high-stability, large-aperture dual-camera common shaped primary mirror, It is characterized in that It comprises a dual primary mirror body (1) and a primary mirror support (2); The double primary mirror body (1) is a combination of two mirror-symmetrical, coaxial single primary mirrors; The primary mirror support (2) is used to realize quasi-static support of the dual primary mirror body (1).

2. According to claim 1, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The double primary mirror body (1) is a ULE sandwich structure, comprising a reflector panel (1.1), an internal sandwich layer (1.2) and a reflector back plate (1.3); the reflector back plate (1.3) is fixedly connected to the primary mirror support (2).

3. According to claim 1, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The single primary mirror in the double primary mirror body (1) is of a configuration with a thick center and a thin edge.

4. According to claim 1, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The optical axis angle of the two single primary mirrors in the double primary mirror body (1) is 16° to 20°, the distance between the vertices of the two single primary mirrors is 600 to 1000 mm, and the aperture of the single primary mirror is 1 to 1.6 m.

5. According to claim 1, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The two single primary mirrors in the double primary mirror body (1) share a reflector back plate (1.3), and the reflector back plate (1.3) provides the same processing, detection, and adjustment reference for the two single primary mirrors.

6. According to claim 1, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The primary mirror support (2) comprises a nested adapter (2.1), a flexible support rod (2.2) and a support base (2.3); The two ends of the flexible support rod (2.2) are respectively connected to the nesting adapter (2.1) and the support base (2.3); the support base (2.3) is connected to the main load-bearing structure, the reflector back plate (1.3) is provided with a reflector nest at the support point, and the nesting adapter (2.1) is used to connect the reflector nest.

7. According to claim 6, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The two primary mirror supports (2) form a group of Bipod structures. The three groups of Bipod structures are distributed in a circle at equal intervals to achieve quasi-static support. The two flexible support rods (2.2) in each group of Bipod structures are spaced at 90 degrees; the two ends of the flexible support rods (2.2) are flexible links.

8. According to claim 6, a high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror, It is characterized in that The three groups of Bipod structures include a total of 6 primary mirror supports (2), forming 6 support points for the primary mirror body (1), wherein the 6 support points are mirror-symmetrical, wherein the distances between four support points and the center of the single primary mirror are 0.65R, and the distances between the remaining two support points and the center of the single primary mirror are 0.5R; R is the radius of the single primary mirror.

9. The high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror according to claim 6, It is characterized in that The reflector back plate (1.3) is provided with a support reinforcement (1.4) at the connection with the nested adapter (2.1).

10. The high-precision, high-stability, large-aperture dual-camera common special-shaped primary mirror according to claim 1, It is characterized in that The double main mirror body (1) is an integrated structure, and the double main mirror body (1) matches the optical systems of two cameras at the same time.

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