Device and method for measuring optical axis error of large-aperture telescope in external field in-situ manner

Abstract

The invention belongs to the technical field of optical adjustment of large-aperture telescopes, and particularly relates to a device and a method for in-situ measurement of optical axis errors of a large-aperture telescope in an external field. The method comprises the following steps: S1, roughly adjusting the four-dimensional adjusting base to enable the auto-collimation light pipe to be aligned with the center of a pitch axis of a to-be-measured piece; s2, rotating the pitch axis of the to-be-measured piece, and adjusting the angle inclination adjusting mechanism to enable the reflecting surface of the plane mirror to be perpendicular to the optical axis of the auto-collimation light pipe, and at the moment, enabling the optical axis of the auto-collimation light pipe to coincide with the pitch axis of the to-be-measured piece; s3, using the to-be-detected piece to track a natural star, when the natural star is located at the center of the detector target surface of the to-be-detected piece, rotating the rotatable pentaprism mechanism to enable the third window to be aligned with the natural star, and enabling the natural star to be imaged on the detector target surface of the auto-collimation light pipe and the detector target surface of the to-be-detected piece at the same time; and S4, calculating a visual axis error of the to-be-measured piece based on the imaging track of the natural star. According to the invention, the process can be simplified, the efficiency can be improved, and the large-aperture telescope optical axis difference can be measured in real time in an out-field on-site manner.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical alignment of large-aperture telescopes, and particularly relates to an in-situ measurement device and method for the visual axis error of a large-aperture telescope in the field. Background Technique

[0002] Large precision telescopes are widely used in fields such as astronomical imaging, aerospace, and calibration of inertial navigation equipment. The telescope tube can point to any position in space driven by the tracking mount. Among them, the telescope tube includes key components such as the primary mirror chamber assembly, secondary mirror assembly, ring beam, truss structure, and cross joint. These components work together to form the visual axis of the telescope; the tracking mount includes an azimuth axis system and an elevation axis system. Theoretically, the azimuth axis is precisely perpendicular to the earth's horizontal plane, and the elevation axis is installed on the azimuth axis and is strictly orthogonal to it. The elevation axis can rotate omnidirectionally in a plane perpendicular to the azimuth axis. The visual axis is installed on the elevation axis and maintains an orthogonal relationship with the elevation axis, and can rotate up and down in a plane perpendicular to the elevation axis. This structural design enables the telescope to flexibly point to the target in three-dimensional space and achieve precise tracking observation. By precisely controlling the rotation angles of the azimuth axis and the elevation axis, the visual axis can be precisely pointed to the target in the air for high-resolution observation or orbital measurement of the target in the air, and the pointing accuracy is an important indicator to measure the system performance.

[0003] For a telescope, the systematic errors caused by processing and alignment and the random errors caused by various factors will result in a deviation between the pointing position output by the telescope and the theoretical position of the space target, manifested as the space target not being imaged at the center of the telescope's field of view, that is, there is a pointing error.

[0004] The existing optical measurement methods are only applicable to the parallax detection of small and medium-sized telescopes because they require the elevation axis of the telescope to rotate 180 degrees, so that the telescope tube is inverted to align with the target in the observation collimator. However, the size and weight of the telescope tube of large telescopes have increased significantly. Restricted by various factors, the telescope tube often cannot be inverted for use, so the traditional parallax detection method cannot be used. Large telescopes generally conduct integrated tests in the field, and large-aperture collimators are not convenient to use in the field. Therefore, the existing optical measurement methods are not applicable to the parallax detection of large-aperture telescopes. Summary of the Invention

[0005] In view of this, the present invention aims to provide an in-situ measurement device and method for the visual axis error of a large-aperture telescope in the external field, so as to solve the problem that the prior art cannot detect and measure the visual axis error of a large-aperture telescope in the external field. The present invention uses the method of observing natural stars to detect the visual axis error, selects the pitch axis as the measurement reference, determines the pitch axis by the method of optical autocollimation, and uses a detector and a pentaprism to receive the natural star target. By using the detector and image processing method, the aiming accuracy is high and no complex manual adjustment is required. The present invention can simplify the process and improve the efficiency.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows: An in-situ measurement device for the visual axis error of a large-aperture telescope in the external field includes an autocollimator, a four-dimensional adjustment base, a rotatable pentaprism mechanism, a plane mirror, and an angle tilt adjustment mechanism. Among them, the autocollimator is mounted on the four-dimensional adjustment base, the four-dimensional adjustment base is assembled on the column of the workpiece to be measured, the rotatable pentaprism mechanism is assembled at the light outlet of the autocollimator, the plane mirror is installed on the angle tilt adjustment mechanism, and the angle tilt adjustment mechanism is assembled on the pitch axis head of the workpiece to be measured. The parallel light emitted by the autocollimator is reflected back to the detector target surface of the autocollimator through the rotatable pentaprism mechanism and the plane mirror in sequence.

[0007] Furthermore, the four-dimensional adjustment base is used to adjust the beam emission direction of the autocollimator, and the adjustment includes horizontal translation adjustment, vertical translation adjustment, azimuth angle adjustment, and pitch angle adjustment of the autocollimator; the angle tilt adjustment mechanism is used to adjust the tilt angle of the plane mirror.

[0008] Furthermore, the rotatable pentaprism mechanism includes a first window, a second window, and a third window. The first window is aligned with the autocollimator, the second window is aligned with the plane mirror, the axes of the first window and the second window are on a straight line, the axis of the third window is perpendicular to the axis of the first window, and the axis of the third window is perpendicular to the axis of the second window. The third window is used to observe natural stars.

[0009] Furthermore, roughly adjust the four-dimensional adjustment base to align the autocollimator with the center of the pitch axis of the workpiece to be measured; rotate the pitch axis of the workpiece to be measured, and roughly adjust the angle tilt adjustment mechanism so that after the light beam emitted by the autocollimator passes through the rotatable pentaprism mechanism and is incident on the plane mirror, the reflected light spot of the plane mirror forms an image on the detector target surface of the autocollimator through the rotatable pentaprism mechanism. Rotate the pitch axis of the workpiece to be measured, and finely adjust the angle tilt adjustment mechanism to adjust the angle of the plane mirror so that the arc-shaped trajectory formed by the light spot set on the detector target surface of the autocollimator changes from a circular arc to a special-shaped circular arc, and record the coordinates of the center O of the critical circular arc during the process of changing from a circular arc to a special-shaped circular arc ( 、 ). Use the device under test to track a natural star. When the natural star is at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism so that the third window is aligned with the natural star. Use the autocollimator and the device under test to observe the natural star simultaneously, and the natural star is imaged on the detector target surface of the autocollimator through the rotatable pentaprism mechanism. Draw a perpendicular line from the center O of the circle to the trajectory of the natural star to obtain the perpendicular point O1 ( 、 ). Based on the center coordinates O ( 、 ) and the perpendicular point O1 ( 、 ), calculate the boresight error of the device under test .

[0010] A method for on-site measurement of the boresight error of a large-aperture telescope in the field, which is realized by using an on-site measurement device for the boresight error of a large-aperture telescope in the field, specifically includes the following steps: S1: Coarsely adjust the four-dimensional adjustment base so that the autocollimator is aligned with the center of the pitch axis of the device under test; S2: Rotate the pitch axis of the device under test and adjust the angle tilt adjustment mechanism so that the reflecting surface of the flat mirror is perpendicular to the optical axis of the autocollimator. At this time, the optical axis of the autocollimator coincides with the pitch axis of the device under test; S3: Use the device under test to track a natural star. When the natural star is at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism so that the third window is aligned with the natural star, and make the natural star image on the detector target surfaces of both the autocollimator and the device under test at the same time; S4: Calculate the boresight error of the device under test based on the imaging trajectory of the natural star.

[0011] Further, step S2 specifically includes the following steps: S21: Coarsely adjust the angle tilt adjustment mechanism to change the tilt of the flat mirror. After the beam emitted by the autocollimator is incident on the flat mirror through the rotatable pentaprism mechanism, the reflected light spot of the flat mirror is imaged on the detector target surface of the autocollimator through the rotatable pentaprism mechanism; S22: Fine-tune the angle tilt adjustment mechanism to adjust the angle of the flat mirror. Rotate the pitch axis of the device under test so that the arc-shaped trajectory formed by the set of light spots on the detector target surface of the autocollimator changes from a circular arc to a special-shaped circular arc, and record the coordinates of the center O of the critical circular arc during the process of changing from a circular arc to a special-shaped circular arc ( 、 ). At this time, the reflecting surface of the flat mirror is perpendicular to the optical axis of the autocollimator

[0012] Further, step S3 specifically includes the following steps: S31: Use the device under test to track natural stars. When a natural star is imaged at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism so that the third window is aligned with the natural star, and make the natural star be imaged on the detector target surface of the autocollimator at the same time; S32: Draw a perpendicular line from the center O to the trajectory of the natural star to obtain the perpendicular point O1 ( , )

[0013] Further, in step S4, based on the center coordinates O ( , ) and the perpendicular point O1 ( , ), calculate the visual axis error of the device under test .

[0014] Compared with the prior art, the present invention can achieve the following beneficial effects: The device and method for measuring the visual axis error of a large-aperture telescope in-situ in the field of the present invention use the method of observing natural stars to detect the visual axis error, select the pitch axis as the measurement reference, determine the pitch axis by the method of optical autocollimation, receive the natural star target with a detector and a pentaprism, and adopt the method of detector and image processing, with high aiming accuracy, no need for complex manual adjustment, which can simplify the process and improve the efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is the main structural view of the device for measuring the visual axis error of a large-aperture telescope in-situ in the field of the embodiment of the present invention; Figure 2 is the top structural view of the device for measuring the visual axis error of a large-aperture telescope in-situ in the field of the embodiment of the present invention; Figure 3 is the structural schematic diagram of the autocollimator of the embodiment of the present invention; Figure 4 is the flow schematic diagram of the method for measuring the visual axis error of a large-aperture telescope in-situ in the field of the embodiment of the present invention; Figure 5 is the schematic diagram of the principle of solving the rotation center of the autocollimation light source detector image of the embodiment of the present invention; Figure 6 is the schematic diagram of solving the visual axis error of the autocollimation detector image of the embodiment of the present invention.

[0016] Description of the reference numerals: 1. Azimuth base; 1-1. Azimuth axis; 2. Turntable; 3. Left vertical column; 4. Right vertical column; 5. Four-way joint; 6. Autocollimator; 6-1. Detector target surface of the autocollimator; 6-1-1. Center of the target surface; 6-2. Light source; 6-3. Beam splitter; 6-4. Lens group; 7. Four-dimensional adjustment base; 8. Rotatable pentaprism mechanism; 8-1. Pentaprism visual axis; 9. Plane mirror; 10. Angle tilt adjustment mechanism; 11. Elevation axis; 11-1. Elevation axis head; 12. Detector target surface of the test piece; 13. Primary mirror; 14. Secondary mirror; 15. Theoretical visual axis of the test piece; 16. Actual visual axis of the test piece; 17. Arc trajectory; 18. Center of the circle; 19. Natural star trajectory; 20. Nadir point; c. Visual axis difference. Specific embodiments

[0017] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0018] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0021] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0022] As Figure 1 - Figure 2 shown, the basic structure of the large-aperture telescope includes an azimuth pedestal 1, a turntable 2, a left column 3, a right column 4, a cross 5, a primary mirror 13, and a secondary mirror 14; the left column 3 and the right column 4 are used to assemble the cross 5, and the left column 3 and the right column 4 are installed on the turntable 2, and the turntable 2 is assembled on the azimuth pedestal 1 to adjust the azimuth angle change of the large-aperture telescope. To avoid the influence of the azimuth rotation of the large-aperture telescope on the line-of-sight measurement, the present invention assembles the outfield in-situ measurement device for the line-of-sight error of the large-aperture telescope at the column and the pitch axis 11 position, so that the entire line-of-sight error measurement device is azimuth-adjusted together with the structure on the turntable 2 (the four-dimensional adjustment pedestal 7 is installed beside the column of the pitch axis 11 and rotates together with the azimuth axis 1-1).

[0023] The outfield in-situ measurement device for the line-of-sight error of the large-aperture telescope includes an autocollimator 6, a four-dimensional adjustment pedestal 7, a rotatable pentaprism mechanism 8, a plane mirror 9, and an angle tilt adjustment mechanism 10. Among them, the autocollimator 6 is mounted on the four-dimensional adjustment pedestal 7, the four-dimensional adjustment pedestal 7 is assembled on the column of the device under test, the rotatable pentaprism mechanism 8 is assembled at the light outlet of the autocollimator 6, the plane mirror 9 is installed on the angle tilt adjustment mechanism 10, and the angle tilt adjustment mechanism 10 is assembled on the pitch axis head 11-1 of the device under test. The parallel light emitted by the autocollimator 6 is reflected back to the detector target surface of the autocollimator 6 successively through the rotatable pentaprism mechanism 8 and the plane mirror 9, and the optical axis direction of the autocollimator 6 is parallel to the pitch rotation axis of the device under test.

[0024] It should be noted that the device under test here is a large-aperture telescope that has been installed in the outfield.

[0025] In some embodiments, the four-dimensional adjustment pedestal 7 is used to adjust the beam emission direction of the autocollimator 6, and the adjustment includes horizontal translation adjustment, vertical translation adjustment, azimuth angle adjustment, and pitch angle adjustment of the autocollimator 6; the angle tilt adjustment mechanism 10 is used to adjust the tilt angle of the plane mirror 9.

[0026] It should be noted that horizontal translation refers to horizontal translation of the optical axis, and the self-collimating light tube 6 is moved in the horizontal direction to adjust the horizontal position of the optical axis. Vertical translation refers to vertical translation of the optical axis, and the self-collimating light tube 6 is moved in the vertical direction to adjust the vertical position of the optical axis. Azimuth adjustment refers to rotating the self-collimating light tube 6 around the vertical axis to adjust the direction of the optical axis in the horizontal plane. Pitch adjustment refers to rotating the self-collimating light tube 6 around the horizontal axis to adjust the direction of the optical axis in the vertical plane.

[0027] In some embodiments, Figure 3 As shown, the self-collimating light tube 6 includes a light source 6-2, a collimating objective lens, a detector, a beam splitter 6-3 and a lens group 6-4, wherein the beam splitter 6-3 and the lens group 6-4 are placed inside the collimating objective lens, the light source 6-2 is connected to the side of the collimating objective lens, and is located at the beam splitting focus formed by the turning of the beam splitter 6-3, the detector is placed at one end of the collimating objective lens, the light beam emitted by the light source 6-2 is sequentially irradiated onto the plane mirror 9 via the beam splitter 6-3, the lens group 6-4 and the rotatable pentaprism mechanism 8, and the light beam reflected by the plane mirror 9 is sequentially imaged onto the detector via the rotatable pentaprism mechanism 8, the lens group 6-4 and the beam splitter 6-3.

[0028] It should be noted that the autocollimation light tube 6 is mounted on a four-dimensional adjustment base 7, and the four-dimensional adjustment base 7 is used to adjust the two-dimensional translational freedom and the two-dimensional angular tilt freedom of the autocollimation light tube 6. The light source 6-2 is connected to the side of the autocollimation light tube 6, and at the splitting focus formed by the beam splitter 6-3, the detector target surface 6-1 of the autocollimation light tube is installed at the focus of the rear end of the autocollimation light tube 6. The plane mirror 9 is installed on the angle tilt adjustment mechanism 10, and the plane reflector is used for the self-collimation measurement of the autocollimation light tube 6 to realize the original path reflection of the parallel light.

[0029] The angle tilt adjustment mechanism 10 is installed together with the plane mirror 9 at the center of the hole in the rotating axis system perpendicular to the rotation axis of the pitch axis 11. The angle tilt adjustment mechanism 10 is used to adjust the two-dimensional angle (azimuth angle and pitch angle) of the plane mirror 9.

[0030] The rotatable pentaprism mechanism 8 is installed at the front end of the autocollimator light tube 6, and the test piece is used to track the natural star. When the natural star is at the center of the detector target surface 12 of the test piece, the rotatable pentaprism mechanism 8 is rotated to align the third window with the natural star. When the test piece (large-aperture telescope) observes the natural star, the autocollimator can also observe the natural star, and the natural star is imaged in the detector of the autocollimator light tube 6 at the same time. The image of the natural star in the detector of the autocollimator light tube 6 is a linear natural star trajectory 19.

[0031] In some embodiments, the rotatable pentaprism mechanism 8 includes a first window, a second window, and a third window. The first window is aligned with the autocollimator 6, the second window is aligned with the plane mirror 9, the axes of the first window and the second window are on the same straight line, the axis of the third window is perpendicular to the axis of the first window, and the axis of the third window is perpendicular to the axis of the second window. The third window is used to observe natural stars.

[0032] In some embodiments, coarsely adjust the four-dimensional adjustment base 7 so that the autocollimator 6 is aligned with the center of the pitch axis 11 of the device under test; rotate the pitch axis 11 of the device under test. The rotation range of the pitch axis 11 is from 0° to 90°, and coarsely adjust the angle tilt adjustment mechanism 10 so that after the light beam emitted by the autocollimator 6 is incident on the plane mirror 9 through the rotatable pentaprism mechanism 8, the reflected light spot of the plane mirror 9 is imaged on the detector target surface of the autocollimator 6 through the rotatable pentaprism mechanism 8. Rotate the pitch axis 11 of the device under test, and finely adjust the angle tilt adjustment mechanism 10 to adjust the angle of the plane mirror 9 so that the arc-shaped trajectory formed by the light spot set on the detector target surface of the autocollimator 6 changes from a circular arc to a special-shaped circular arc, and record the coordinates O ( 、 )of the center 18 of the critical circular arc during the process of changing from a circular arc to a special-shaped circular arc; Use the device under test to track natural stars. When the natural star is at the center of the detector target surface 12 of the device under test, rotate the rotatable pentaprism mechanism 8 so that the third window is aligned with the natural star. Use the autocollimator 6 and the device under test to observe the natural star simultaneously, and the natural star is imaged on the detector target surface of the autocollimator 6 through the rotatable pentaprism mechanism 8. Draw a perpendicular line from the center 18 to the natural star trajectory 19 to obtain the coordinates O1 ( 、 )of the perpendicular point 20; Based on the coordinates O ( 、 )of the center 18 and the coordinates O1 ( 、 )of the perpendicular point 20, calculate the visual axis difference of the device under test .

[0033] It should be noted that when the pitch axis 11 of the component to be measured is rotated, the rotation range of the pitch axis 11 is from 0° to 90°. The set of reflected light spots corresponding to the plane mirror 9 forms a 1 / 4 arc trajectory (i.e., an arc trajectory) on the detector of the autocollimator 6. By controlling the rotation speed of the pitch axis 11, the set of light spots is made to present a circular state on the detector of the autocollimator 6. The smaller the radius of the arc trajectory 17, the higher the perpendicularity of the reflecting surface of the plane mirror 9 to the optical axis of the autocollimator 6. During the process of adjusting the angle of the plane mirror 9, the arc will gradually transform into a special-shaped arc. At this time, there is a critical point, that is, the point with the smallest radius that maintains the arc shape. Beyond this critical point, it is a special-shaped arc trajectory. In actual operation, the perpendicularity of the reflecting surface of the plane mirror 9 to the optical axis of the autocollimator 6 cannot be adjusted to be absolutely perpendicular, that is, the radius of the arc trajectory is 0. Therefore, the radius of the arc trajectory that meets the requirements is used as the adjustment reference to determine the perpendicularity of the reflecting surface of the plane mirror 9 to the optical axis of the autocollimator 6.

[0034] As Figure 4 shown, the present invention also provides a method for measuring the optical axis error of a large-aperture telescope in the field, which is realized by using a device for measuring the optical axis error of a large-aperture telescope in the field, and specifically includes the following steps: S1: Coarsely adjust the four-dimensional adjustment base 7 to align the autocollimator 6 with the center of the pitch axis 11 of the component to be measured; S2: Rotate the pitch axis 11 of the component to be measured and adjust the angle tilt adjustment mechanism 10 to make the reflecting surface of the plane mirror 9 perpendicular to the optical axis of the autocollimator 6. At this time, the optical axis of the autocollimator 6 coincides with the pitch axis 11 of the component to be measured; S3: Use the component to be measured to track a natural star. When the natural star is at the center of the detector target surface 12 of the component to be measured, rotate the rotatable pentaprism mechanism 8 to align the third window with the natural star, so that the natural star is imaged on the detector target surface 6-1 of the autocollimator and the detector target surface 12 of the component to be measured at the same time; S4: Calculate the optical axis error of the component to be measured based on the imaging trajectory of the natural star.

[0035] In some embodiments, step S2 specifically includes the following steps: S21: Coarsely adjust the angle tilt adjustment mechanism 10 to change the inclination of the plane mirror 9. After the light beam emitted by the autocollimator 6 is incident on the plane mirror 9 through the rotatable pentaprism mechanism 8, the reflected light spot of the plane mirror 9 is imaged on the detector target surface of the autocollimator 6 through the rotatable pentaprism mechanism 8; S22: Fine-tune the angle tilt adjustment mechanism 10 to adjust the angle of the plane mirror 9. Rotate the pitch axis 11 of the component to be measured to make the arc trajectory formed by the set of light spots on the detector target surface of the autocollimator 6 transform from an arc to a special-shaped arc, and record the coordinates O of the center 18 of the critical arc during the process of transforming from an arc to a special-shaped arc ( 、 ), at this time, the reflecting surface of the plane mirror 9 is perpendicular to the optical axis of the autocollimator 6

[0036] After the optical axis of the autocollimator 6 coincides with the pitching axis 11 of the device under test, it can ensure that after the device under test tracks the natural star in the subsequent steps, the autocollimator 6 can also image the natural star.

[0037] In some embodiments, step S3 specifically includes the following steps: S31: Use the device under test to track the natural star. When the natural star is imaged at the center of the detector target surface 12 of the device under test, rotate the rotatable pentaprism mechanism 8 to align the third window with the natural star, so that the natural star is simultaneously imaged on the detector target surface of the autocollimator 6; S32: Draw a perpendicular line from the center of the circle 18 to the natural star trajectory 19 to obtain the coordinates O1 of the perpendicular point 20 ( 、 )

[0038] In some embodiments, in step S4, based on the coordinates O ( 、 ) of the center of the circle 18 and the coordinates O1 ( 、 ) of the perpendicular point 20, calculate the visual axis difference of the device under test .

[0039] The specific operations are summarized as follows: Coarsely adjust the vertical translation and horizontal translation of the four-dimensional adjustment base 7 to roughly align the autocollimator 6 with the center of the pitching axis 11 of the device under test (the large-aperture telescope installed in the field); Rotate the pitching axis 11 (the rotation range of the pitching axis 11 is from 0° to 90°), and coarsely adjust the azimuth and pitch of the angle tilt adjustment mechanism 10 and the four-dimensional adjustment base 7 to ensure that the image point of the light spot can always be imaged within the detector target surface of the autocollimator 6; As Figure 5 shown, rotate the pitching axis 11 and finely adjust the angle tilt adjustment mechanism 10 to make the light spot image on the detector target surface of the autocollimator 6 approach the center of the circle 18 of the circular trajectory of the light spot image; Since there are mutual influences among the adjustment degrees of freedom, it is necessary to repeatedly adjust and iterate the previous step until the circular trajectory of the light spot image is minimized or even does not form a circle, and record the coordinates O ( 、 ) of the center of the circular trajectory of the light spot image at this time. At this time, the optical axis of the autocollimator 6 coincides with the pitching axis 11 of the device under test.

[0040] As Figure 6As shown, the large-aperture telescope after the installation of the control external field tracks and observes a natural star; ensure that the natural star remains stationary at the center of the detector target surface of the telescope (after the optical axis of the autocollimator 6 coincides with the pitch axis 11 of the device under test, the natural star is imaged at the center of the detector target surface of the large-aperture telescope), the rotatable pentaprism mechanism 8 can be rotated so that the natural star observed by the large-aperture telescope after the installation of the external field is simultaneously imaged in the detector of the autocollimator 6; record the straight-line trajectory drawn by the natural star in the detector of the autocollimator 6 due to the rotatable pentaprism mechanism 8, draw a perpendicular line from the center 18 of the circular trajectory of the spot image to the natural star trajectory 19, and record the imaging coordinates O1 of the natural star passing through the rotatable pentaprism mechanism 8 in the detector of the autocollimator 6 ( , ). Finally, calculate the optical axis difference .

[0041] It should be understood that the various forms of the processes shown above can be used, re-ordered, steps added or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0042] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An in-situ measurement device for the optical axis error of a large-aperture telescope in an external field, characterized in that: It includes an autocollimator, a four-dimensional adjustment base, a rotatable pentaprism mechanism, a plane mirror and an angle tilt adjustment mechanism. Among them, the autocollimator is mounted on the four-dimensional adjustment base, the four-dimensional adjustment base is assembled on the column of the device under test, the rotatable pentaprism mechanism is assembled at the light outlet of the autocollimator, the plane mirror is installed on the angle tilt adjustment mechanism, the angle tilt adjustment mechanism is assembled on the pitch axis head of the device under test, and the parallel light emitted by the autocollimator is reflected back to the detector target surface of the autocollimator through the rotatable pentaprism mechanism and the plane mirror in sequence.

2. The device for on-site measurement of the optical axis error of a large-aperture telescope according to claim 1, characterized in that: The four-dimensional adjustment base is used to adjust the beam emission direction of the autocollimator. The adjustment includes horizontal translation adjustment, vertical translation adjustment, azimuth angle adjustment, and pitch angle adjustment of the autocollimator; the angle tilt adjustment mechanism is used to adjust the tilt angle of the plane mirror.

3. The device for on-site measurement of the visual axis error of a large-aperture telescope according to claim 2, wherein: The rotatable pentaprism mechanism includes a first window, a second window and a third window. The first window is aligned with the autocollimator, the second window is aligned with the plane mirror, the axes of the first window and the second window are on a straight line, the axis of the third window is perpendicular to the axis of the first window, and the axis of the third window is perpendicular to the axis of the second window. The third window is used to observe natural stars.

4. The on-site measurement device for the optical axis error of a large-aperture telescope according to claim 3, characterized in that: Coarsely adjust the four-dimensional adjustment base to align the autocollimator with the center of the pitching axis of the component under test; rotate the pitching axis of the component under test and coarsely adjust the angle tilt adjustment mechanism so that after the light beam emitted by the autocollimator is incident on the plane mirror through the rotatable pentaprism mechanism, the reflected light spot of the plane mirror is imaged on the detector target surface of the autocollimator through the rotatable pentaprism mechanism. Rotate the pitching axis of the component under test and finely adjust the angle tilt adjustment mechanism to adjust the angle of the plane mirror so that the arc-shaped trajectory formed by the light spot set on the detector target surface of the autocollimator changes from a circular arc to a special-shaped circular arc, and record the coordinates of the center O of the critical circular arc during the process of changing from a circular arc to a special-shaped circular arc ( , ); Use the device under test to track natural stars. When the natural star is at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism so that the third window is aligned with the natural star. Observe the natural star simultaneously with the autocollimator and the device under test, and the natural star is imaged on the detector target surface of the autocollimator through the rotatable pentaprism mechanism. Draw a perpendicular line from the center O to the trajectory of the natural star to obtain the perpendicular point O1 ( , ); Based on the center coordinate O( , ) and the perpendicular point O1( , ), calculate the visual axis difference of the measured part.

5. A method for on-site measurement of the optical axis error of a large-aperture telescope in an external field, which is realized by using the device for on-site measurement of the optical axis error of a large-aperture telescope in an external field described in any one of claims 1 to 4, and is characterized in that: Specifically, it includes the following steps: S1: Coarsely adjust the four-dimensional adjustment base to align the autocollimator with the center of the pitch axis of the device under test; S2: Rotate the pitch axis of the device under test and adjust the angle tilt adjustment mechanism to make the reflecting surface of the plane mirror perpendicular to the optical axis of the autocollimator. At this time, the optical axis of the autocollimator coincides with the pitch axis of the device under test; S3: Use the device under test to track natural stars. When the natural star is at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism to align the third window with the natural star, so that the natural star is imaged on the detector target surfaces of both the autocollimator and the device under test at the same time; S4: Calculate the visual axis error of the device under test based on the imaging trajectory of the natural star.

6. The method for measuring the optical axis error of a large-aperture telescope in-situ in an external field according to claim 5, characterized in that: Step S2 specifically includes the following steps: S21: Coarsely adjust the angle tilt adjustment mechanism to change the tilt of the plane mirror. After the light beam emitted by the autocollimator is incident on the plane mirror through the rotatable pentaprism mechanism, the light spot reflected by the plane mirror is imaged on the detector target surface of the autocollimator through the rotatable pentaprism mechanism; S22: Fine-tune the angle tilt adjustment mechanism to adjust the angle of the plane mirror, rotate the pitch axis of the device under test, so that the arc trajectory formed by the spot set on the detector target surface of the autocollimator changes from a circular arc to a special-shaped circular arc, and record the coordinates of the center O of the critical circular arc during the process of changing from a circular arc to a special-shaped circular arc ( , ). At this time, the reflecting surface of the plane mirror is perpendicular to the optical axis of the autocollimator.

7. The method for measuring the optical axis error of a large-aperture telescope in-situ in an external field according to claim 6, wherein: Step S3 specifically includes the following steps: S31: Use the device under test to track natural stars. When the natural star is imaged at the center of the detector target surface of the device under test, rotate the rotatable pentaprism mechanism to align the third window with the natural star, so that the natural star is imaged on the detector target surface of the autocollimator at the same time; S32: Draw a perpendicular line from the center O to the natural star trajectory to obtain the perpendicular point O1 ( , ).

8. The method for measuring the optical axis error of a large-aperture telescope in-situ in an external field according to claim 7, wherein: In step S4, based on the center coordinate O ( , ), and the foot of the perpendicular O1 ( , ), calculate the visual axis difference of the part to be measured.

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