Calibration method for inertial measurement unit of airborne photoelectric platform

Abstract

The invention provides a calibration method for an inertial measurement unit of an airborne photoelectric platform, and belongs to the technical field of precision optical machine installation and adjustment, and the method comprises the following steps: S1, detecting and adjusting the intersection degree of the position of an azimuth pitch axis system of the airborne platform; s2, calibration and precision detection are carried out on a rotating shaft of an azimuth pitch axis system of the airborne platform; s3, detecting and adjusting the perpendicularity of the azimuth pitch axis system of the airborne platform; s4, carrying out orthogonality detection and adjustment on the optical axis and the shaft system of the photoelectric platform; and S5, calibrating the coordinate system deviation of the inertial measurement unit. According to the method provided by the invention, through a series of optical machine adjustment steps, the shafting precision adjustment of the airborne platform and the deviation calibration of the inertial measurement unit are completed at the same time, the orthogonal coordinate system adjustment and positioning of the shafting and the optical axis of the airborne photoelectric platform are realized, and the deviation value of the inertial measurement unit and the orthogonal coordinate system is tested. And the information is fed back to a data processing subsystem to realize geometric space correlation calculation.

Description

Technical Field

[0001] The invention relates to the technical field of precision optical-mechanical assembly and adjustment, and in particular provides a calibration method for an inertial measurement unit of an airborne optoelectronic platform. Background Art

[0002] At present, most of the payload equipment in the field of airborne optoelectronic detection and countermeasures adopts a two-axis two-frame or two-axis four-frame configuration design. The more common one is that the multi-band sensor is highly integrated on a stable platform. The platform is connected to the outer shell through the azimuth axis system and the pitch axis system. Through the rotation of the two axis systems, it can achieve steering and detection at any position in space. The general configuration of the airborne optoelectronic platform is shown in the attached Figure 1 As shown, it is mainly composed of an optoelectronic stabilization platform 1, an azimuth axis system 2, a pitch axis system 3, and a pitch frame 4. The azimuth axis system 2 and the pitch axis system 3 are respectively composed of two semi-axes, each with its own rotation axis. The rotation axes intersect and are perpendicular to each other in space, and can be detected and adjusted separately. At the same time, in order to make the optical axis of the subsequent platform identifiable and monitorable, an optical axis identification reference reflection surface is reserved during the platform assembly. This reflection surface has been precisely adjusted and fixed, and will be used as the optical axis reference of the platform optical system in the future.

[0003] According to the navigation control principle, inertial navigation equipment such as aircraft need to be motion controlled, and their attitude needs to be precisely calculated. The inertial measurement unit is a strapdown inertial navigation, which can provide angular velocity and acceleration information respectively. The inertial measurement unit is a device that measures the three-axis attitude angle or angular rate and acceleration of an object. The general inertial measurement unit contains three single-axis accelerometers and three single-axis gyroscopes, among which the accelerometer is used to detect the acceleration signal of the object in the independent three axes in the carrier coordinate system, and the gyroscope is used to detect the angular velocity signal of the carrier relative to the navigation coordinate system. By measuring the angular velocity and acceleration of the object in three-dimensional space, the spatial attitude of the object is calculated based on this, which has important application value in navigation. The general inertial measurement unit is installed on the center of gravity of the airborne optoelectronic stabilization platform. After the initial assembly, there is an angular error between the measurement unit and the coordinate system composed of the axis system and the optical axis. Therefore, it is necessary to accurately measure this error and calibrate the error of the inertial measurement unit. Summary of the invention

[0004] The purpose of the present application is to provide a method for calibrating an inertial measurement unit of an airborne optoelectronic platform. The method calibrates the inertial measurement unit by detecting and adjusting the intersection of the azimuth and pitch axis positions of the airborne platform, detecting the rotation accuracy of the two axis systems and calibrating the rotation axis, detecting and calibrating the verticality of the two axis systems, detecting and calibrating the orthogonality of the platform optical axis and the axis system, and calibrating the coordinate system error of the inertial measurement unit.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for calibrating an inertial measurement unit of an airborne optoelectronic platform, wherein the airborne optoelectronic platform comprises an optoelectronic stabilized platform, an azimuth axis system, a pitch axis system and a pitch frame arranged on the optoelectronic stabilized platform, wherein the azimuth axis system and the pitch axis system are respectively composed of two semi-axes, each having a rotation axis, and the rotation axes are intersecting and perpendicular in spatial position, and the method comprises:

[0006] S1: Detect and adjust the intersection of the azimuth and pitch axis positions of the airborne platform;

[0007] S2: Calibrate and perform accuracy test on the azimuth and pitch axis system of the airborne platform;

[0008] S3: Check and adjust the verticality of the azimuth and pitch axis system of the airborne platform;

[0009] S4: Check and adjust the orthogonality of the optical axis and axis system of the optoelectronic platform;

[0010] S5: Calibrate the inertial measurement unit coordinate system deviation.

[0011] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has such a technical feature that S1 comprises:

[0012] S1.1: Set up the airborne optoelectronic platform on the marble platform by adjusting the supporting fixture, and place the axes on both sides of the azimuth axis horizontally;

[0013] S1.2: Use a height gauge to detect the center height of the half-axis rotation axis on both sides of the azimuth axis system, and adjust the posture of the photoelectric stabilization platform to make the azimuth axis parallel to the marble platform plane;

[0014] S1.3: Use a height meter to check the center height of the rotation axis of the half-axes on both sides of the pitch axis system. Adjust the heights of the half-axes on both sides of the pitch axis system to be the same by rotating them up and down, and record the vertical height H1 from the center to the plane of the height meter;

[0015] S1.4: Rotate the pitch axis 180° counterclockwise around the azimuth axis, repeat S1.3 to record the center to the altimeter plane and adjust the vertical height H2;

[0016] S1.5: Calculate the difference between the vertical height H1 from the center to the altimeter plane and the adjusted vertical height H2 from the center to the altimeter plane. The difference H1-H2 is the intersection degree of the axis system position.

[0017] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has the following technical features: S1 also includes comparing the axis position intersection index with the airborne optoelectronic platform azimuth pitch axis position intersection index; if the index requirements are not met, adjusting the axis positions of the half axes on both sides of the pitch axis system and repeating S1.3-S1.5.

[0018] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has such a technical feature that S2 comprises:

[0019] S2.1: Assemble the transfer fixture to the corresponding half-axes of the azimuth axis system and the pitch axis system to connect and tighten the azimuth axis system and the pitch axis system;

[0020] S2.2: Attach the multi-dimensional adjustable reflector to the adapter fixture, respectively mount the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube at the working distance in front of the multi-dimensional adjustable reflector, perform coarse collimation through the laser collimation viewfinder of the multi-dimensional adjustable reflector, adjust the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube, so that the multi-dimensional adjustable reflector autocollimation image enters the detection field of view;

[0021] S2.3: Finely adjust the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube to collimate the image to the center position, rotate the axis system at a constant speed, collect image points in real time, draw a fitting circle, and obtain the angular rotation accuracy;

[0022] S2.4: Adjust the azimuth and pitch angle of the multi-dimensional adjustable reflector to move the image point toward the center of the circle, and repeat S2.3 until the angular rotation accuracy is minimized. At this time, the normal line of the multi-dimensional adjustable reflector surface is the axis of the rotation axis, and the calibration and accuracy detection of the azimuth and pitch axis system rotation axis are completed.

[0023] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has the following technical features: S3 includes: placing a pentaprism at the intersection of the first optoelectronic autocollimation light tube and the second optoelectronic autocollimation light tube, the incident surface of the pentaprism is aligned with the first optoelectronic autocollimation light tube, and the light beam is emitted through the pentaprism and then observed through the second optoelectronic autocollimation light tube. At this time, the autocollimation image deviation value is the verticality deviation of the axis system.

[0024] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has the following technical feature: S3 also includes adjusting the verticality deviation of the axis system by adjusting the position of the azimuth axis system.

[0025] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has such a technical feature that S4 comprises:

[0026] S4.1: Two reflection surfaces are provided outside the inertial measurement unit to replace its working axis, and the two reflection surfaces include a reference optical reflection surface of the first axis of the measurement unit and a reference optical reflection surface of the second axis of the measurement unit;

[0027] S4.2: Place a pentaprism in front of the first photoelectric autocollimation light tube, adjust the incident surface of the pentaprism to align with the first photoelectric autocollimation light tube, ensure that the outgoing light beam of the pentaprism and the incident light beam are in the same horizontal plane, set up a third photoelectric autocollimation light tube behind the outgoing light beam, the third photoelectric autocollimation light tube is installed in the enveloping area of ​​the second axis reference optical reflection surface of the measuring unit, and adjust the third photoelectric autocollimation light tube to make it orthogonal to the first photoelectric autocollimation light tube;

[0028] S4.3: remove the pentaprism, set up a fourth photoelectric autocollimation light tube in front of the third photoelectric autocollimation light tube, and adjust the azimuth and elevation angles of the fourth photoelectric autocollimation light tube to align it with the third photoelectric autocollimation light tube;

[0029] S4.4: Set up a large-aperture standard plane mirror in front of the first photoelectric autocollimation light tube, align the large-aperture standard plane mirror with the first photoelectric autocollimation light tube, set up the fifth photoelectric autocollimation light tube in the area enveloping the reference optical reflection surface of the first axis of the measuring unit, adjust the fifth photoelectric autocollimation light tube to align it with the large-aperture standard plane mirror, and the orthogonality detection and adjustment of the optical axis of the photoelectric platform and the axis system is completed.

[0030] The airborne optoelectronic platform inertial measurement unit calibration method provided by the present invention also has such a technical feature that S5 comprises:

[0031] S5.1: Install the inertial measurement unit at the center of gravity of the optoelectronic stabilization platform and place it on the two-dimensional adjustment platform after assembly;

[0032] S5.2: Adjust the azimuth and elevation angles of the two-dimensional platform so that the first photoelectric self-collimation light tube and the second photoelectric self-collimation light tube are aligned with the multi-dimensional adjustable reflector respectively;

[0033] S5.3: Adjust the position of the photoelectric stabilization platform so that its optical axis identification reference reflection surface is aligned with the fourth photoelectric self-collimation light tube;

[0034] S5.4: Directly observe the deviation values ​​of the first axis reference optical reflection surface and the second axis reference optical reflection surface of the inertial measurement unit through the third photoelectric autocollimation light tube and the fifth photoelectric autocollimation light tube, and feed them back to the data processing subsystem to complete the deviation calibration of the inertial measurement unit.

[0035] Beneficial Effects

[0036] The method provided by the present invention performs the detection and calibration of the intersection of the azimuth and pitch axis systems of the airborne platform, the detection of the rotation accuracy of the two axis systems and the calibration of the rotation axis, the detection and calibration of the verticality of the two axis systems, the detection and calibration of the orthogonality of the platform optical axis and the axis system, the calibration of the coordinate system error of the inertial measurement unit, etc. Through the above series of optical and mechanical calibration steps, the precise adjustment of the axis system of the airborne platform and the deviation calibration of the inertial measurement unit are completed at the same time, the orthogonal coordinate system adjustment and positioning of the axis system and the optical axis of the airborne optoelectronic platform are realized, the deviation value between the inertial measurement unit and the orthogonal coordinate system is tested, and then fed back to the data processing subsystem to realize the geometric space correlation solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 This is a composition diagram of the airborne optoelectronic platform mentioned in the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of the inertial measurement unit mentioned in the present invention;

[0040] Figure 3 This is the principle diagram of axis position intersection detection;

[0041] Attached Figure 4 This is the principle diagram of shaft system rotation accuracy detection;

[0042] Attached Figure 5 This is the principle diagram of shaft verticality detection;

[0043] Attached Figure 6 Create schematics for calibration benchmarks;

[0044] Attached Figure 7 Schematic diagram for calibration of inertial measurement unit.

[0045] Among them, 1: optoelectronic stabilization platform; 2: azimuth axis system; 3: pitch axis system; 4: pitch frame; 5: first axis reference optical reflection surface; 6: second axis reference optical reflection surface; 7: marble platform; 8: altimeter; 9: multi-dimensional adjustable reflector; 10: adapter; 11: first optoelectronic autocollimation light tube; 12: second optoelectronic autocollimation light tube; 13: pentaprism; 14: third optoelectronic autocollimation light tube; 15: fourth optoelectronic autocollimation light tube; 16: fifth optoelectronic autocollimation light tube; 17: large-aperture standard plane mirror; 18: inertial measurement unit. DETAILED DESCRIPTION

[0046] The present application is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation methods are not limitations of the present application, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation methods are all within the scope of protection of the present application.

[0047] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the creation of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present application.

[0048] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0049] The terms "installed", "connected" and "connected" 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of this application can be understood by specific circumstances.

[0050] like Figure 3-7 As shown, an embodiment of the present invention provides a method for calibrating an inertial measurement unit of an airborne optoelectronic platform, the method comprising:

[0051] S1: Detect and adjust the position intersection of the azimuth and pitch axis systems of the airborne platform. Use the altimeter to detect the center height of the axis system. Fix the rotation axis of one side of the axis system and rotate the axis system on the other side to re-detect the center height. Compare the before and after to calculate the position intersection of the two axis systems. Feedback the axis adjustment direction based on the detection results to complete the position intersection adjustment.

[0052] S2: Calibrate and test the accuracy of the rotation axis of the azimuth and pitch axis system of the airborne platform. Connect the multi-dimensional adjustable reflector fixture with the azimuth and pitch axis system, align the reflector with the photoelectric self-collimation light tube, adjust the azimuth and pitch angles of the reflector, and test the rotation accuracy of the axis system.

[0053] S3: Detect and adjust the verticality of the azimuth and pitch axis system of the airborne platform. After the calibration of the two rotating axes is completed, the verticality detection of the axis system can be carried out. Use two photoelectric self-collimation tubes and a pentaprism to set up the spatial rectangular coordinate system. Use this rectangular coordinate system to detect the verticality of the two axis systems, and complete the verticality adjustment through the feedback of the detection results;

[0054] S4: Detect and adjust the orthogonality of the optical axis and the axis system of the optoelectronic platform. After the platform azimuth, the intersection degree of the pitch axis system, and the verticality are adjusted, the optoelectronic self-collimation light tube and the pentaprism are used to set up the optical axis adjustment reference, so that the 0° field of view incident optical axis of the optoelectronic platform and the two rotating axis systems form a pairwise orthogonal spatial reference coordinate system.

[0055] S5: Calibrate the deviation of the inertial measurement unit coordinate system. Since the orthogonal space coordinate system has been detected and calibrated, under this benchmark, with the help of the inertial measurement unit's own working axis detection benchmark, the inertial measurement unit deviation can be directly detected and calibrated through the photoelectric self-collimation light tube.

[0056] In some embodiments, Figure 3 As shown, the S1 includes:

[0057] S1.1: The airborne optoelectronic platform is set up on the marble platform 7 by adjusting the supporting fixture, and the axes on both sides of the azimuth axis 2 are placed horizontally;

[0058] S1.2: Use the altimeter 8 to detect the center height of the half-axis rotation axis on both sides of the azimuth axis system 2, and adjust the posture of the photoelectric stabilization platform 1 so that the centers of the half-axis on both sides are at the same height, that is, to ensure that the azimuth axis is parallel to the plane of the marble platform 7;

[0059] S1.3: Use the altimeter 8 to detect the center height of the rotation axis of the half-axes on both sides of the pitch axis system 3, adjust the heights of the half-axes on both sides of the pitch axis system 3 to be the same by rotating up and down, and record the vertical height H1 from the center to the plane of the altimeter 8, that is, the distance between the solid line in the figure and the altimeter 8;

[0060] S1.4: Rotate the semi-axis of the elevation axis system 3 180° counterclockwise around the axis of the azimuth axis system 2, and repeat S1.3 to adjust the vertical height H2 from the recording center to the plane of the altimeter 8, i.e., the distance between the dotted line in the attached figure and the altimeter 8;

[0061] S1.5: Calculate the difference between the vertical height H1 from the center to the plane of the altimeter 8 and the adjusted vertical height H2 from the center to the plane of the altimeter 8. The difference H1-H2 is the intersection degree of the axis position.

[0062] In some embodiments, S1 further includes comparing the axis position intersection index with the azimuth and pitch axis position intersection index of the airborne optoelectronic platform. If the index requirement is not met, the axis positions of the half axes on both sides of the pitch axis 3 are adjusted and S1.3-S1.5 are repeated.

[0063] In some embodiments, Figure 4 As shown, the S2 includes:

[0064] S2.1: Assemble the transfer fixture 10 to the corresponding half-axes of the azimuth axis system 2 and the pitch axis system 3, so that the azimuth axis system 2 and the pitch axis system 3 are connected and fastened;

[0065] S2.2: The multi-dimensional adjustable reflector 9 is correspondingly transferred to the transfer fixture 10, and the first photoelectric self-collimation light tube 11 and the second photoelectric self-collimation light tube 12 are respectively set at the working distance in front of the multi-dimensional adjustable reflector 9, and the laser collimation image finder of the multi-dimensional adjustable reflector 9 is used for rough collimation, and the first photoelectric self-collimation light tube 11 and the second photoelectric self-collimation light tube 12 are adjusted to make the self-collimation image of the multi-dimensional adjustable reflector 9 enter the detection field of view;

[0066] S2.3: Finely adjust the first photoelectric autocollimation light tube 11 and the second photoelectric autocollimation light tube 12 to collimate the image to the center position, rotate the axis system at a constant speed, collect image points in real time, generally sample 30 points in one circle, draw a fitting circle, and read the 2ΔR value, which is the angular rotation accuracy;

[0067] S2.4: Adjust the azimuth and pitch angle of the multi-dimensional adjustable reflector 9 to move the image point to the center of the circle, and repeat S2.3 until the angular rotation accuracy is minimized. At this time, the normal line of the multi-dimensional adjustable reflector 9 is the axis of the rotation axis, and the azimuth pitch axis system rotation axis is calibrated and the accuracy test is completed. After the adjustment, the position of the multi-dimensional adjustable reflector 9 and the adapter 10 is adjusted.

[0068] In some embodiments, Figure 5 As shown, S3 includes: placing a pentaprism 13 at the intersection of the first photoelectric self-collimation light tube 11 and the second photoelectric self-collimation light tube 12, the incident surface of the pentaprism 13 is aligned with the first photoelectric self-collimation light tube 11, and the light beam is emitted through the pentaprism 13 and observed by the second photoelectric self-collimation light tube 12. At this time, the self-collimation image deviation value is the axis verticality deviation.

[0069] In some embodiments, S3 also includes adjusting the verticality deviation of the axis system by adjusting the position of the azimuth axis system 2, and rechecking with reference to the azimuth pitch axis system position intersection detection route, and after the deviations of the two axis systems are adjusted, the axis system pins are matched.

[0070] In some embodiments, after the platform axis system is adjusted, the orthogonality of the azimuth and pitch axis systems meets the requirements, and the next step is to adjust the optical axis of the platform and the azimuth and pitch axis systems to be orthogonal to each other, that is, to form an orthogonal coordinate system. Figure 6 As shown, the S4 includes:

[0071] S4.1: Two reflective surfaces are set outside the inertial measurement unit 18 to replace its working axis, such as Figure 2 As shown, the two reflection surfaces include a first axis reference optical reflection surface 5 and a second axis reference optical reflection surface 6;

[0072] S4.2: Place a pentaprism 13 in front of the first photoelectric self-collimating light tube 11, adjust the incident surface of the pentaprism 13 to align with the first photoelectric self-collimating light tube 11, ensure that the outgoing light beam of the pentaprism 13 and the incident light beam are in the same horizontal plane, set up a third photoelectric self-collimating light tube 14 behind the outgoing light beam, the third photoelectric self-collimating light tube 14 is installed in the envelope area of ​​the second axis reference optical reflection surface 6, and adjust the third photoelectric self-collimating light tube 14 to make it orthogonal to the first photoelectric self-collimating light tube 11;

[0073] S4.3: remove the pentaprism 13, set up a fourth photoelectric self-collimation light tube 15 in front of the third photoelectric self-collimation light tube 14, and adjust the azimuth and elevation angles of the fourth photoelectric self-collimation light tube 15 so that it is aligned with the third photoelectric self-collimation light tube 14;

[0074] S4.4: A large-aperture standard plane mirror 17 is set up in front of the first photoelectric self-collimating light tube 11, and the large-aperture standard plane mirror 17 is aligned with the first photoelectric self-collimating light tube 11. A fifth photoelectric self-collimating light tube 16 is set up in the envelope area of ​​the first axis reference optical reflection surface 5, and the fifth photoelectric self-collimating light tube 16 is adjusted to align it with the large-aperture standard plane mirror 17. Then, the orthogonality detection and adjustment of the optical axis of the photoelectric platform and the axis system is completed.

[0075] In some embodiments, Figure 7 As shown, the S5 includes:

[0076] S5.1: Install the inertial measurement unit 18 at the center of gravity of the optoelectronic stabilization platform 1, and place it on the two-dimensional adjustment platform after assembly;

[0077] S5.2: Adjust the azimuth and elevation angles of the two-dimensional platform so that the first photoelectric self-collimation light tube 11 and the second photoelectric self-collimation light tube 12 are aligned with the multi-dimensional adjustable reflector 9 respectively;

[0078] S5.3: Adjust the position of the photoelectric stabilization platform 1 so that its optical axis identification reference reflection surface is aligned with the fourth photoelectric self-collimation light tube 15;

[0079] S5.4: Directly observe the deviation values ​​of the first axis reference optical reflection surface 5 and the second axis reference optical reflection surface 6 of the inertial measurement unit 18 through the third photoelectric self-collimation light tube 14 and the fifth photoelectric self-collimation light tube 16, and feed them back to the data processing subsystem to complete the deviation calibration of the inertial measurement unit.

[0080] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for calibrating an inertial measurement unit of an airborne optoelectronic platform, wherein the airborne optoelectronic platform comprises an optoelectronic stabilized platform, an azimuth axis system, a pitch axis system and a pitch frame arranged on the optoelectronic stabilized platform, wherein the azimuth axis system and the pitch axis system are respectively composed of two semi-axes, each having a rotation axis, and the rotation axes are intersecting and perpendicular in spatial position, and characterized in that: The method comprises: S1: Detect and adjust the intersection of the azimuth and pitch axis positions of the airborne platform; S2: Calibrate and perform accuracy test on the azimuth and pitch axis system of the airborne platform; S3: Check and adjust the verticality of the azimuth and pitch axis system of the airborne platform; S4: Detect and adjust the orthogonality of the optical axis and axis system of the optoelectronic platform; S5: Calibrate the inertial measurement unit coordinate system deviation.

2. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 1, characterized in that: The S1 includes: S1.1: Set up the airborne optoelectronic platform on the marble platform by adjusting the supporting fixture, and place the axes on both sides of the azimuth axis horizontally; S1.2: Use a height gauge to detect the center height of the half-axis rotation axis on both sides of the azimuth axis system, and adjust the posture of the photoelectric stabilization platform so that the azimuth axis is parallel to the marble platform plane; S1.3: Use a height meter to check the center height of the half-axes on both sides of the pitch axis system. Adjust the heights of the half-axes on both sides of the pitch axis system to be the same by rotating them up and down. Record the vertical height H1 from the center to the plane of the height meter. S1.4: Rotate the pitch axis 180° counterclockwise around the azimuth axis, repeat S1.3 to record the center to the altimeter plane and adjust the vertical height H2; S1.5: Calculate the difference between the vertical height H1 from the center to the altimeter plane and the adjusted vertical height H2 from the center to the altimeter plane. The difference H1-H2 is the intersection degree of the axis system position.

3. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 2, characterized in that: The S1 also includes comparing the intersection degree of the axis system position with the intersection degree index of the azimuth and pitch axis system position of the airborne optoelectronic platform. If the index requirement is not met, the axis system positions of the half axes on both sides of the pitch axis system are adjusted and S1.3-S1.5 are repeated.

4. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 1, characterized in that: The S2 includes: S2.1: Assemble the transfer fixture to the corresponding half-axes of the azimuth axis system and the pitch axis system to connect and tighten the azimuth axis system and the pitch axis system; S2.2: Attach the multi-dimensional adjustable reflector to the adapter fixture, respectively mount the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube at the working distance in front of the multi-dimensional adjustable reflector, perform coarse collimation through the laser collimation viewfinder of the multi-dimensional adjustable reflector, adjust the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube, so that the multi-dimensional adjustable reflector autocollimation image enters the detection field of view; S2.3: Finely adjust the first photoelectric autocollimation light tube and the second photoelectric autocollimation light tube to collimate the image to the center position, rotate the axis system at a constant speed, collect image points in real time, draw a fitting circle, and obtain the angular rotation accuracy; S2.4: Adjust the azimuth and pitch angle of the multi-dimensional adjustable reflector to move the image point toward the center of the circle, and repeat S2.3 until the angular rotation accuracy is minimized. At this time, the normal line of the multi-dimensional adjustable reflector surface is the axis of the rotation axis, and the calibration and accuracy detection of the azimuth and pitch axis system rotation axis are completed.

5. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 1, characterized in that: S3 includes: placing a pentaprism at the intersection of the first photoelectric self-collimation light tube and the second photoelectric self-collimation light tube, the incident surface of the pentaprism is aligned with the first photoelectric self-collimation light tube, and the light beam is observed through the second photoelectric self-collimation light tube after being emitted through the pentaprism. At this time, the self-collimation image deviation value is the axis verticality deviation.

6. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 5, characterized in that: The S3 also includes adjusting the verticality deviation of the axis system by adjusting the position of the azimuth axis system.

7. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 1, characterized in that: The S4 includes: S4.1: Two reflection surfaces are provided outside the inertial measurement unit to replace its working axis, and the two reflection surfaces include a reference optical reflection surface of the first axis of the measurement unit and a reference optical reflection surface of the second axis of the measurement unit; S4.2: Place a pentaprism in front of the first photoelectric autocollimation light tube, adjust the incident surface of the pentaprism to align with the first photoelectric autocollimation light tube, ensure that the outgoing light beam of the pentaprism and the incident light beam are in the same horizontal plane, set up a third photoelectric autocollimation light tube behind the outgoing light beam, the third photoelectric autocollimation light tube is installed in the enveloping area of ​​the second axis reference optical reflection surface of the measuring unit, and adjust the third photoelectric autocollimation light tube to make it orthogonal to the first photoelectric autocollimation light tube; S4.3: remove the pentaprism, set up a fourth photoelectric autocollimation light tube in front of the third photoelectric autocollimation light tube, and adjust the azimuth and elevation angles of the fourth photoelectric autocollimation light tube to align it with the third photoelectric autocollimation light tube; S4.4: Set up a large-aperture standard plane mirror in front of the first photoelectric autocollimation light tube, align the large-aperture standard plane mirror with the first photoelectric autocollimation light tube, set up the fifth photoelectric autocollimation light tube in the area enveloping the reference optical reflection surface of the first axis of the measuring unit, adjust the fifth photoelectric autocollimation light tube to align it with the large-aperture standard plane mirror, and the orthogonality detection and adjustment of the optical axis of the photoelectric platform and the axis system is completed.

8. The method for calibrating an airborne optoelectronic platform inertial measurement unit according to claim 1, characterized in that: The S5 includes: S5.1: Install the inertial measurement unit at the center of gravity of the optoelectronic stabilization platform and place it on the two-dimensional adjustment platform after assembly; S5.2: Adjust the azimuth and elevation angles of the two-dimensional platform so that the first photoelectric self-collimation light tube and the second photoelectric self-collimation light tube are aligned with the multi-dimensional adjustable reflector respectively; S5.3: Adjust the position of the photoelectric stabilization platform so that its optical axis identification reference reflection surface is aligned with the fourth photoelectric self-collimation light tube; S5.4: Directly observe the deviation values ​​of the first axis reference optical reflection surface and the second axis reference optical reflection surface of the inertial measurement unit through the third photoelectric autocollimation light tube and the fifth photoelectric autocollimation light tube, and feed them back to the data processing subsystem to complete the deviation calibration of the inertial measurement unit.

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