Kuder optical path correction method based on laser emission

Abstract

The invention relates to a Kuder optical path correction method based on laser emission. Firstly, a plane mirror 19 is used for calibrating the installation position of an auto-collimation observation mirror 2 on a laser emission fixing bin 1; replacing a plane mirror 19 with a standard pentaprism 5, and calibrating the arrangement position of the optical theodolite 4 by using the standard pentaprism 5; replacing the standard pentaprism 5 with a Kuder mirror I 11, and determining the mounting position of the Kuder mirror I 11 by using the auto-collimation observation mirror 2 and the optical theodolite 4; and finally, a servo stable rotary table azimuth frame 10 and a servo stable rotary table pitching frame 7 are sequentially mounted on the laser emission fixing bin 1, and an azimuth axis and a pitching axis of the Kuder optical path are respectively corrected by using a laser 8 and a front lens 6. The method has the advantages of simplicity in operation, high correction efficiency, high field adaptability, convenience in equipment disassembly and assembly and the like, the Kuder optical path can be simply and quickly corrected, the optical path deviation is effectively eliminated, and the accuracy and the reliability of optical measurement are improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical equipment and measurement and debugging, and in particular to a Coode optical path correction method based on laser emission. Background Art

[0002] As an important optical system platform, large optoelectronic turntables are widely used in aerospace, astronomical observation, national defense science and technology, etc. The Kude optical path is a light guide that can turn the light beam to rotate with the axis system. The laser beam passing through the Kude optical path can be free from the influence of the turntable rotation and thus be emitted in a predetermined direction.

[0003] With the continuous development of science and technology, the requirements for the accuracy and stability of optical systems are getting higher and higher. However, due to the influence of the mechanical structure, materials and environmental factors of the turntable itself, the internal Coode optical path system often deviates, which ultimately leads to inaccurate laser ranging and laser irradiation targets. Therefore, the correction of the Coode optical path of a large turntable has important practical application value and is a key means to achieve high-precision and high-stability optical measurement. Its stability and accuracy directly affect the accuracy of optical measurement. Summary of the invention

[0004] The purpose of the present invention is to overcome the above problems existing in the prior art and provide a method for Coode optical path correction based on laser emission, which can conveniently and quickly correct the Coode optical path, effectively eliminate optical path deviation, and improve the accuracy and reliability of optical measurement. To achieve the above purpose, the specific scheme adopted by the present invention is as follows:

[0005] The laser-emitting Coode optical path correction method comprises the following steps: (a) installing a plane mirror 19 and an autocollimation observation mirror 2 inside and on the top of a laser emission fixed chamber 1, respectively, and calibrating the installation position of the autocollimation observation mirror 2 by using the plane mirror 19; (b) placing an optical theodolite 4 on the right side of the laser emission fixed chamber 1, replacing the plane mirror 19 with a standard pentaprism 5 in situ, and then calibrating the arrangement position of the optical theodolite 4; (c) replacing the standard pentaprism 5 with a Coode mirror I11, and determining the installation position of the Coode mirror I11 by using the autocollimation observation mirror 2 and the optical theodolite 4; (d) replacing the optical theodolite 4 with a laser 8, and correcting the azimuth axis and the pitch axis of the Coode optical path.

[0006] Furthermore, in step (a), the plane mirror 19 is horizontally arranged in the cavity inside the laser emission fixed chamber 1, and the autocollimation observation mirror 2 is vertically fixed to the top of the laser emission fixed chamber 1 through a tooling and is connected to the interior of the laser emission fixed chamber 1, and the autocollimation observation mirror 2 is opposite to the middle part of the plane mirror 19.

[0007] Furthermore, the self-collimating observation mirror 2 is connected to a high-definition display 3 , and a cross-mark line is arranged inside the self-collimating observation mirror 2 .

[0008] Furthermore, the calibration method of the installation position of the autocollimation observation mirror 2 in step (a) is as follows: the cross-line of the autocollimation observation mirror 2 is reflected by the plane mirror 19 and then re-enters the autocollimation observation mirror 2. With the help of the high-definition display 3, it is observed whether the cross-line of the autocollimation observation mirror 2 itself and the reflected cross-line coincide with each other. If they coincide, the calibration of the installation position of the autocollimation observation mirror 2 is completed. If they do not coincide, the installation position of the autocollimation observation mirror 2 is repeatedly adjusted to make them coincide.

[0009] Furthermore, the calibration process of the arrangement position of the optical theodolite 4 in step (b) is specifically as follows: after replacing the plane mirror 19 with the standard pentaprism 5 in situ, the cross-reticle lines of the autocollimation observation mirror 2 are reflected by the standard pentaprism 5 to the optical theodolite 4, and it is observed whether the cross-reticle lines of the reflected autocollimation observation mirror 2 coincide with the cross-reticle lines of the optical theodolite 4 itself. If they coincide, the calibration of the arrangement position of the optical theodolite 4 is completed; if they do not coincide, the height and left and right arrangement positions of the optical theodolite 4 are adjusted to make them coincide.

[0010] Furthermore, the specific process of determining the installation position of the Coode mirror I11 in step (c) is as follows: replace the standard pentaprism 5 with the Coode mirror I11, and the cross-line of the autocollimation observation mirror 2 is reflected by the Coode mirror I11 and enters the optical theodolite 4, and observe whether the reflected cross-line of the autocollimation observation mirror 2 coincides with the cross-line of the optical theodolite 4 itself. If they coincide, confirm the installation position of the Coode mirror I11; if they do not coincide, adjust the layout position of the Coode mirror I11 to make them coincide.

[0011] Furthermore, in step (d), the azimuth axis of the Coode optical path is first calibrated, and then the elevation axis of the Coode optical path is calibrated.

[0012] Furthermore, the process of correcting the azimuth axis of the Kude optical path in step (d) is specifically as follows: the laser 8 is arranged in the laser emission fixed warehouse 1 and is located between the optical theodolite 4 and the Kude mirror I11, and the position of the laser 8 is adjusted so that the cursor of the optical theodolite 4 is directly opposite to the center of the laser 8, thereby completing the preliminary correction of the installation position of the laser 8; the laser 8 is fixed and the optical theodolite 4, the autocollimation observation mirror 2 and the supporting parts (such as the tooling and the display) are removed, and the servo-stabilized turntable azimuth frame 10 is installed on the upper surface of the laser emission fixed warehouse 1, and the front mirror 6 is installed on the servo-stabilized turntable azimuth frame 10; the front mirror 6 is rotated, and the laser emitted by the laser 8 is reflected by the Kude mirror I11 and enters the front mirror 6 to form a light spot, and the position and offset of the light spot during the rotation of the front mirror 6 along the azimuth axis are observed. If the light spot rotates along its own center position without offset, lock the servo stabilization turntable 10 and the laser 8 to complete the azimuth axis correction. Otherwise, continue to adjust the height and left and right installation positions of the laser 8 until the position and offset of the laser spot during the rotation of the front mirror 6 along the azimuth axis approach zero.

[0013] Furthermore, the front mirror 6 is rotated clockwise or counterclockwise for at least one circle during the process of correcting the azimuth axis of the Coode optical path.

[0014] Furthermore, the process of correcting the pitch axis of the Coode optical path in step (d) is as follows: after correcting the azimuth axis of the Coode optical path, remove the front mirror 6, install the servo stabilized turntable pitch frame 7 on the servo stabilized turntable azimuth frame 10, and then install the Coode mirrors II 12 to V15 inside the servo stabilized turntable pitch frame 7, and then install the front mirror 6 on the top of the servo stabilized turntable pitch frame 7 and make it face the Coode mirror V15; rotate the front mirror 6, the laser emitted by the laser 8 is reflected by the Coode mirrors I11 to V15 and then enters the front mirror 6 to form a light spot, and observe the position and offset of the light spot during the rotation of the front mirror 6 along the pitch axis. If the light spot rotates along its own center position without offset, lock the servo stabilization turntable pitch frame 7 and Kude mirror II 12 to Kude mirror V15 to complete the pitch axis correction, otherwise continue to adjust the installation position of the trimmed Kude mirror II 12 to Kude mirror V15 until the position and offset of the laser spot during the rotation of the front mirror 6 along the pitch axis approach zero.

[0015] Furthermore, the front mirror 6 is rotated clockwise or counterclockwise by at least 0.5 turns during the process of calibrating the pitch axis.

[0016] Compared with the existing similar technologies, the advancement and beneficial effects of the present invention are mainly reflected in the following points: (1) It can effectively eliminate the deviation of the Kude optical path of a large turntable and improve the accuracy and reliability of laser irradiation and ranging; (2) It is simple to operate and easy to use, has no special requirements for the test site, and the correction system is easy to build, and can simply and quickly correct the Kude optical path; (3) This method can avoid errors caused by human eye aiming, external environment, etc. through the high-definition and magnified display of the display screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the composition of the Kude optical path.

[0018] Figure 2 Schematic diagram of calibrating the self-collimating viewing mirror.

[0019] Figure 3 Schematic diagram for calibrating the position of the optical theodolite.

[0020] Figure 4 Schematic diagram of the correction of the azimuth axis of the Coode optical path.

[0021] Figure 5 Schematic diagram of the correction of the pitch axis of the Kude optical path.

[0022] Figure 6 Schematic diagram of the self-collimating cursor.

[0023] Description of the drawings: 1-laser emission fixed warehouse, 2-autocollimation observation mirror, 3-high-definition display, 4-optical theodolite, 5-standard pentaprism, 6-front mirror, 7-servo stabilized turntable pitch frame, 8-laser, 9-computer, 10-servo stabilized turntable azimuth frame, 11-Kude mirror I, 12-Kude mirror II, 13-Kude mirror III, 14-Kude mirror IV, 15-Kude mirror V, 16-pitch axis, 17-azimuth axis, 18-autocollimation observation mirror fixing tooling, 19-plane mirror, 20-middle frame. DETAILED DESCRIPTION

[0024] In order to enable ordinary technicians in the field to fully understand the technical solutions and beneficial effects of the present invention, further description is given below in conjunction with specific embodiments and drawings.

[0025] The laser emission Kude optical path optical axis correction system provided by the present invention mainly includes a laser emission fixed warehouse 1, an autocollimation observation mirror 2, a high-definition display 3, an optical theodolite 4, a standard pentaprism 5, a front mirror 6, a servo-stabilized turntable pitch frame 7, a laser 8, a computer 9, a servo-stabilized turntable azimuth frame 10, a Kude mirror I11, a Kude mirror II 12, a Kude mirror III 13, a Kude mirror IV 14, a Kude mirror V15, an autocollimation observation mirror fixing tool 18, a plane mirror 19, and a middle frame 20. The functions and effects of the above-mentioned components are as follows:

[0026] The laser emission fixed warehouse 1 is used to install the calibrated laser 8 and the pitch and azimuth frames of the servo-stabilized turntable. The autocollimation observation mirror 2 is used to observe the autocollimation image reflected by the plane mirror 19 to ensure that the installation surface of the autocollimation observation mirror 2 is perpendicular to the plumb plane. The high-definition display 3 is used to display in real time the degree of overlap between the cross-reticle observed by the autocollimation observation mirror 2 and the cross-reticle reflected back. The optical theodolite 4 is mainly used to calibrate the laser emission optical axis. The standard pentaprism 5 is used to deflect the light by 90° so that it enters a specific optical device. The front mirror 6 is used to observe the optical axis change of the laser emission optical axis during the rotation of the servo-stabilized turntable and make corresponding adjustments. The servo-stabilized turntable pitch frame 7 can rotate along the pitch axis 16, and a Coudé mirror is installed inside it. The laser 8 is used to generate and emit laser light for overall correction. The computer 9 is used to control the turntable movement and record data. The servo-stabilized turntable azimuth frame 10 can rotate along the azimuth axis 17, and a Coudé mirror is also installed inside it. The Coudé mirror is used to reflect light in a directional manner. The autocollimation observation mirror fixing fixture 18 is used to fix the autocollimation observation mirror 2. The plane mirror 19 is used to reflect the autocollimation image of the autocollimation observation mirror 2. The middle frame 20 is used to connect and lock the servo stabilization turntable pitch frame 7.

[0027] The structure of the Kude optical path is as follows Figure 1 As shown, it includes five Kude mirrors numbered IV. Among them, Kude mirror I11 is arranged with an angle of 45° facing the upper right side, Kude mirror II 12 is arranged symmetrically with Kude mirror I11 along the X-axis, Kude mirror III 13 is parallel to Kude mirror II 12 and is dispersedly arranged at a certain distance, Kude mirror IV 14 is arranged symmetrically with Kude mirror III 13 along the X-axis, Kude mirror V15 is parallel to Kude mirror IV 14 and is dispersedly arranged at a certain distance, and Kude mirror IV 14 and Kude mirror V15 can rotate along the pitch axis and azimuth axis. The laser is shot parallel to Kude mirror I11 from the right side, and is reflected by Kude mirrors II-V in turn and then shot vertically upward. It can be seen from the analysis that when installing and calibrating the Kude optical path, it is first necessary to ensure that the position of Kude mirror I11 is accurately installed, and use this as a reference to calibrate other Kude mirrors II-V while installing.

[0028] To this end, we designed a new correction system. This correction system adopts a separate design. Each component is assembled together according to the direction of the optical path. During the correction process, the installation position of each component is adjusted according to the needs of the optical axis. The corresponding Couder optical path correction method mainly includes: (1) Calibration of the installation position of the autocollimation observation mirror; (2) Calibration of the position of the optical theodolite 4; (3) Calibration of the installation position of the Couder mirror I; (4) Calibration of the azimuth axis; (5) Calibration of the pitch axis. The specific process of each step is as follows:

[0029] like Figure 2As shown, when calibrating the installation position of the autocollimation observation mirror 2, first fix a plane mirror 19 horizontally on the bottom surface inside the laser emission fixed chamber 1, then install the autocollimation observation mirror fixing fixture 18 on the upper surface of the laser emission fixed chamber 1, and then fix the autocollimation observation mirror 2 vertically on the autocollimation observation mirror fixing fixture 18 to ensure that the autocollimation observation mirror 2 is facing the plane mirror 19, and finally connect the cable at the tail of the autocollimation observation mirror 2 to the high-definition display 3. The cross-line inside the autocollimation observation mirror 2 is reflected by the plane mirror 19 and then enters the autocollimation observation mirror 2 again. With the help of the high-definition display 3, the position and overlap of the cross-line of the autocollimation observation mirror 2 itself and the cross-line reflected by the plane mirror 19 are observed. The position of the autocollimation observation mirror 2 is continuously adjusted according to the observation situation until the two cross-line completely overlaps (such as Figure 6 As shown), at this time, the installation surface of the autocollimation observation mirror 2 is perpendicular to the plumb plane and parallel to the horizontal plane, and the installation position of the autocollimation observation mirror 2 is confirmed.

[0030] like Figure 3 As shown, the position of the optical theodolite 4 is calibrated after the installation position of the autocollimation observation mirror 2 is determined. The plane mirror 19 is replaced with the standard pentaprism 5 in situ, and the optical theodolite 4 is arranged on the right side of the outside of the laser emission fixed chamber 1 and facing the standard pentaprism 5. The position of the optical theodolite 4 is slightly adjusted, and the cross-reticles of the autocollimation observation mirror 2 reflected by the standard pentaprism 5 are observed through the optical theodolite 4 to see whether they coincide with the cross-reticles of the optical theodolite 4 itself. Once they coincide, it is determined that the position of the optical theodolite 4 is arranged, otherwise the position of the optical theodolite 4 continues to be adjusted.

[0031] Before calibrating the azimuth axis, Figure 3 On the basis of the above, the standard pentaprism 5 is replaced with the Coudé mirror I11 in situ, and the position of the optical theodolite 4 calibrated previously is kept unchanged. In the same way, observe the degree of overlap between the cross-reticle of the autocollimation observation mirror 2 reflected by the Coudé mirror I11 and the cross-reticle of the optical theodolite 4 itself. At this time, the two cross-reticles are roughly overlapped. If there is a deviation, the Coudé mirror I11 is slightly adjusted to make them completely overlap. At this point, the installation position of the Coudé mirror I11 is also determined.

[0032] like Figure 4As shown, after installing the Kude mirror I11, keep its position fixed, arrange the laser 8 inside the laser emission fixed warehouse 1, and the laser 8 is located between the optical theodolite 4 and the Kude mirror I11. The cursor of the optical theodolite 4 is directly opposite to the center of the laser 8, thereby preliminarily determining the installation position of the laser 8. Then remove the optical theodolite 4, the self-collimating observation mirror 2 and its fixed tooling (i.e. 18), and the high-definition display 3, and replace them with the servo-stabilized turntable azimuth frame 10 installed on the upper surface of the laser emission fixed warehouse 1, and then fix the front mirror 6 on the fixed seat at the top of the servo-stabilized turntable azimuth frame 10, at this time, the axis of the front mirror 6 and the center of the servo-stabilized turntable azimuth frame 10 coincide and face the Kude mirror I11, and the tail of the front mirror 6 is connected to the computer 9 through a cable and controlled by it. The laser 8 emits visible red light, which is reflected into the front mirror 6 by the Kude mirror I11, and the position and size information of the light spot formed after the reflected red light enters the front mirror 6 is observed by the computer 9. Rotate the front mirror 6 clockwise or counterclockwise for one circle, observe the movement of the light spot, ensure that the light spot only rotates along its own center position and the offset approaches zero during the rotation of the front mirror 6, thereby completing the correction of the azimuth axis, and tighten the servo-stabilized turntable azimuth frame 10 and the laser 8 by locking the screws; otherwise, continue to adjust the height, left and right installation positions of the laser 8, so that the light spot only rotates along its own center position and the offset approaches zero during the rotation of the front mirror 6.

[0033] like Figure 5 When calibrating the pitch axis, in the previous step Figure 4 On the basis of the servo-stabilized turntable, remove the front mirror 6, install the servo-stabilized turntable pitch frame 7 on the servo-stabilized turntable azimuth frame 10, and then install the Kude mirrors II 12 to V15 to the corresponding positions inside the servo-stabilized turntable pitch frame 7, respectively, and ensure that the middle frame of the servo-stabilized turntable pitch frame 7 remains absolutely horizontal and motionless by means of stop screws, and install the front mirror 6 above the middle frame so that it faces the Kude mirror V15. Control the laser 8 to emit visible red light, and the light is transmitted to the front mirror 6 through the Kude mirror IV, and the position and size of the light spot can be observed through the computer 9. Rotate the front mirror 6 half a circle clockwise or counterclockwise, observe the movement of the light spot through the computer 9, and continuously adjust the installation positions of the trimmed Kude mirrors II 12 to V15 to ensure that during the rotation of the front mirror 6, the light spot only rotates along its own center position and the offset approaches zero, thereby completing the correction of the pitch axis.

[0034] The laser-emission-based Coode optical path correction system and correction method provided by the present invention are simple to operate, easy to use, have no special requirements for the test site, can effectively eliminate optical path deviations, and improve the accuracy and reliability of optical measurements.

Claims

1. A Coode optical path correction method based on laser emission, characterized in that The method comprises the following steps: (a) installing a plane mirror (19) and an autocollimation observation mirror (2) on a laser emission fixed chamber (1) respectively, and calibrating the installation position of the autocollimation observation mirror (2) using the plane mirror (19); (b) placing the optical theodolite (4) outside the laser emission fixed chamber (1), replacing the plane mirror (19) with a standard pentaprism (5), and calibrating the arrangement position of the optical theodolite (4); (c) replacing the standard pentaprism (5) with a Kudet mirror I (11), and determining the installation position of the Kudet mirror I (11) using the autocollimation observation mirror (2) and the optical theodolite (4); (d) The optical theodolite (4) is replaced by a laser (8) to calibrate the azimuth axis and elevation axis of the Kude optical path.

2. The method according to claim 1, characterized in that: In step (a), the plane mirror (19) is horizontally arranged in the cavity inside the laser emission fixed chamber (1), and the autocollimation observation mirror (2) is vertically fixed to the top of the laser emission fixed chamber (1) through a tool and is connected to the inside of the laser emission fixed chamber (1), and the autocollimation observation mirror (2) is directly opposite to the middle of the plane mirror (19).

3. The method according to claim 1, characterized in that: The self-collimating observation mirror (2) is connected to a high-definition display (3), and a cross-marking line is arranged inside the self-collimating observation mirror (2).

4. The method according to claim 3, characterized in that The method for calibrating the installation position of the autocollimation observation mirror (2) in step (a) is specifically as follows: the cross-marked lines on the autocollimation observation mirror (2) are reflected by the plane mirror (19) and then re-enter the autocollimation observation mirror (2), and a high-definition display (3) is used to observe whether the cross-marked lines of the autocollimation observation mirror (2) itself and the reflected cross-marked lines coincide with each other. If they coincide, the calibration of the installation position of the autocollimation observation mirror (2) is completed; if they do not coincide, the installation position of the autocollimation observation mirror (2) is adjusted to make them coincide.

5. The method according to claim 1, characterized in that The calibration process of the arrangement position of the optical theodolite (4) in step (b) is specifically as follows: the plane mirror (19) is replaced in situ with a standard pentaprism (5), the cross-reticle lines of the autocollimation observation mirror (2) are reflected by the standard pentaprism (5) to the optical theodolite (4), and it is observed whether the reflected cross-reticle lines of the autocollimation observation mirror (2) coincide with the cross-reticle lines of the optical theodolite (4) itself. If they coincide, the calibration of the arrangement position of the optical theodolite (4) is completed; if they do not coincide, the arrangement position of the optical theodolite (4) is adjusted to make them coincide.

6. The method according to claim 1, characterized in that The specific process of determining the installation position of the Coudé mirror I (11) in step (c) is as follows: the standard pentaprism (5) is replaced by the Coudé mirror I (11), and the cross-reticle of the autocollimation observation mirror (2) is reflected by the Coudé mirror I (11) and enters the optical theodolite (4), and it is observed whether the reflected cross-reticle of the autocollimation observation mirror (2) coincides with the cross-reticle of the optical theodolite (4) itself. If they coincide, the installation position of the Coudé mirror I (11) is confirmed; if they do not coincide, the arrangement position of the Coudé mirror I (11) is adjusted to make them coincide.

7. The method according to claim 1, characterized in that: In step (d), the azimuth axis of the Coode optical path is first calibrated, and then the elevation axis of the Coode optical path is calibrated.

8. The method according to claim 7, characterized in that The process of correcting the azimuth axis of the Kude optical path in step (d) is specifically as follows: the laser (8) is arranged inside the laser emission fixed chamber (1), and the position of the laser (8) is adjusted so that the cursor of the optical theodolite (4) is directly opposite to the center of the laser (8), thereby preliminarily correcting the installation position of the laser (8); the laser (8) is fixed and the optical theodolite (4) and the autocollimation observation mirror (2) are removed, and the servo-stabilized turntable azimuth frame (10) is installed on the upper surface of the laser emission fixed chamber (1), and the front mirror (6) is installed on the servo-stabilized turntable. The front mirror (6) is rotated, and the laser light emitted by the laser (8) is reflected by the Kude mirror I (11) and enters the front mirror (6) to form a light spot. The position and offset of the light spot during the rotation of the front mirror (6) along the azimuth axis are observed. If the light spot rotates along its own center position without offset, the servo stabilization turntable (10) and the laser (8) are locked to complete the azimuth axis correction. Otherwise, the installation position of the laser (8) is continuously adjusted until the position and offset of the laser spot during the rotation of the front mirror (6) approach zero.

9. The method according to claim 8, characterized in that: After the azimuth axis of the Coudé optical path is calibrated, the front mirror (6) is removed, the servo-stabilized turntable pitch frame (7) is mounted on the servo-stabilized turntable azimuth frame (10), and then Coudé mirrors II (12) to V (15) are mounted inside the servo-stabilized turntable pitch frame (7), and then the front mirror (6) is mounted on the top of the servo-stabilized turntable pitch frame (7) and is facing the Coudé mirror V (15); the front mirror (6) is rotated, and the laser light emitted by the laser (8) is transmitted by the Coudé mirrors I (11) to V (15) 5) After reflection, the light enters the front mirror (6) to form a light spot. Observe the position and offset of the light spot during the rotation of the front mirror (6) along the pitch axis. If the light spot rotates along its own center position without offset, lock the servo stabilization turntable pitch frame (7) and the Kude mirror II (12) to the Kude mirror V (15) to complete the pitch axis calibration. Otherwise, continue to adjust the installation position of the trimmed Kude mirror II (12) to the Kude mirror V (15) until the position and offset of the laser spot during the rotation of the front mirror (6) along the pitch axis approach zero.

10. The method according to claim 8 or 9, characterized in that: In the process of correcting the azimuth axis of the Kude optical path, the front mirror (6) is rotated clockwise or counterclockwise for at least one turn, and in the process of correcting the elevation axis, the front mirror (6) is rotated clockwise or counterclockwise for at least 0.5 turn.

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