Space camera micro-vibration image motion measurement system and method

Abstract

The invention provides a space camera micro-vibration image motion measurement system and method, and the system comprises an image motion measurement channel integrated on a space camera, and a laser light source, a light source angle adjustment device, a ground image collection device and a ground analysis processing system which are only used for ground measurement. And ground and in-orbit micro-vibration testing of the high-resolution camera can be realized at the same time. The image motion measurement channel can image a laser light source erected at a light inlet of the camera or ground scenery information to a high-frame-frequency detector specially used for micro-vibration measurement, and image motion information of a normal imaging channel of the camera is obtained through conversion by using an image detection algorithm and a data correction method. The image motion measurement channel and the normal imaging channel on the space camera can work simultaneously and share the main optical reflection element, so that high-precision image motion measurement can be realized.

Description

Technical Field

[0001] This invention belongs to the field of micro-vibration testing technology for spacecraft interference sources, and specifically relates to a micro-vibration image shift measurement system and method for space cameras. Background Technology

[0002] During their operation in orbit, space cameras are affected by various sources of vibration, such as the momentum wheel and solar panels of moving parts on the satellite, and the internal cooling and scanning mechanisms of the camera. The movement of these moving parts can cause the camera's optical axis to jitter, and the image formed by the focal plane to shift (referred to as image shift), which in turn affects the image quality. Therefore, high-resolution space cameras need to conduct high-precision analysis, testing and control of the effects of micro-vibrations throughout the entire process from ground to in-orbit.

[0003] Traditional methods for assessing the impact of camera micro-vibrations involve establishing a satellite-camera finite element simulation model, conducting acceleration response tests on the actual camera using modal or micro-vibration experiments to obtain acceleration response data for key camera components, and then refining the finite element model accordingly. Further simulation analysis is then performed to determine the angular changes of various optical elements affecting the camera's optical axis jitter, and this result is used in the optical sensitivity matrix to assess focal plane image shift. However, this method cannot directly establish a mapping relationship between acceleration response and image shift. Furthermore, the amplitude of satellite micro-vibrations is small, resulting in significant measurement errors. The finite element model also differs from the actual camera, making accurate correction difficult and leading to large calculation errors. Therefore, this method cannot intuitively and accurately reflect the impact of micro-vibrations on image quality.

[0004] To directly evaluate the optical axis jitter performance of a camera, Chinese patent 201810617609.1 discloses a verification system for the optical axis jitter performance of a high-resolution spacecraft camera. This system uses a light source-target-parallel light tube as a scene simulator. After the light passes through the camera, it is received by an integrated measuring instrument. Data processing accurately simulates the micro-vibration law of the optical axis. However, the integrated measuring instrument used in this system is an external device and cannot achieve on-orbit evaluation of micro-vibrations. The paper "A High-Resolution Space Camera Micro-Vibration Measurement Method Based on Target Images" introduces a method that extracts grayscale values ​​from the target image on the focal plane. Chinese Patent 201910662419.6 discloses a method for measuring the optical axis micro-vibration of a remote sensing satellite camera by measuring changes in the centroid. This method obtains the on-orbit micro-vibration optical axis disturbance by calculating the changes in consecutive frames of images. Both methods evaluate image movement or optical axis disturbance by directly analyzing the image formed by the camera's focal plane. The test accuracy is high and can be implemented for both ground and on-orbit measurements. However, this image analysis-based method requires a high image sampling frequency, i.e., the imaging frame rate must be at least several times the micro-vibration sensitive frequency, which is not applicable to low frame rate imaging cameras. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the inventors have conducted intensive research and provided a space camera micro-vibration image shift measurement system and method. Based on image processing, the system can simultaneously measure the micro-vibration image shift of the space camera on the ground and in orbit. The ground test system is simple to build, has high test accuracy, and is applicable to low frame rate space cameras.

[0006] The technical solution provided by this invention is as follows: In a first aspect, a space camera micro-vibration image motion measurement system includes a laser light source, a light source angle adjustment device, optical components of the image motion measurement channel optical path, a focal plane detector of the image motion measurement channel, ground image acquisition equipment, and a ground analysis and processing system. The optical components of the image shift measurement channel include a primary optical reflective element, an image shift switching mirror, an image shift folding mirror, and an image shift lens group. The primary optical reflective element is the same as that in the normal imaging channel of a space camera. In the optical path, the primary mirror, secondary mirror, folding mirror, third mirror, and fourth mirror are arranged in sequence. After the primary optical reflective element in the normal imaging channel, the infrared folding mirror, infrared lens group, and infrared focal plane detector are arranged in sequence. The image shift switching mirror and the image shift folding mirror are reflective mirrors. The image shift switching mirror is in a retracted state during normal imaging. During image shift measurement, it cuts into the optical path between the fourth mirror and the infrared folding mirror, introducing light into the image shift measurement channel. After passing through the image shift folding mirror and the image shift lens group, the light is imaged on the focal plane detector of the image shift measurement channel. The laser source, source angle adjustment device, ground image acquisition equipment, and ground analysis and processing system are only used for ground micro-vibration testing. The optical components of the image shift measurement channel and the focal plane detector of the image shift measurement channel are integrated with the space camera as a component of the camera and are used for ground and on-orbit micro-vibration testing. Under ground-based micro-vibration testing conditions, the laser source serves as the ground-based light source. The laser light enters the space camera through the light inlet at the top of the lens support frame. An image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, guiding the light into the image shift measurement channel and imaging it onto the focal plane detector of the image shift measurement channel. The ground-based image acquisition equipment samples the focal plane image of the image shift measurement channel and stores it in a time sequence. The ground-based analysis and processing system reads the stored image and determines the image shift P at the characteristic frequency of the image shift measurement channel. 像移 The ground analysis and processing system uses finite element analysis to determine the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation. Based on P... 成像 =P 像移 +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 determines the displacement of the normal imaging channel of the space camera, where Δ6, Δ7, and Δ8 are the vibration sensitivities of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror, respectively. Under on-orbit micro-vibration testing conditions, the image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, imaging the ground scene onto the focal plane detector of the image shift measurement channel. After sampling by the on-board analysis and processing system, the image shift P at the characteristic frequency of the image shift measurement channel is determined. 像移 Using P 成像 =P 像移 With +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 and the known θ6', θ7', and θ8', the image shift of the normal imaging channel is obtained.

[0007] Secondly, a method for measuring micro-vibration image displacement of a space camera includes: Under ground-based micro-vibration testing conditions, the laser source serves as the ground-based light source. The laser light enters the space camera through the light inlet at the top of the lens support frame. An image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, guiding the light into the image shift measurement channel and imaging it onto the focal plane detector of the image shift measurement channel. The ground-based image acquisition equipment samples the focal plane image of the image shift measurement channel and stores it in a time sequence. The ground-based analysis and processing system reads the stored image and determines the image shift P at the characteristic frequency of the image shift measurement channel. 像移 The ground analysis and processing system uses finite element analysis to determine the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation. Based on P... 成像 =P 像移 +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 determines the displacement of the normal imaging channel of the space camera, where Δ6, Δ7, and Δ8 are the vibration sensitivities of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror, respectively. Under on-orbit micro-vibration testing conditions, the image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, imaging the ground scene onto the focal plane detector of the image shift measurement channel. After sampling by the on-board analysis and processing system, the image shift P at the characteristic frequency of the image shift measurement channel is determined. 像移 Using P 成像 =P 像移 With +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 and the known θ6', θ7', and θ8', the image shift of the normal imaging channel is obtained.

[0008] The space camera micro-vibration image shift measurement system and method provided by the present invention have the following beneficial effects: (1) The present invention provides a space camera micro-vibration image movement measurement system and method, which adds an image movement measurement channel to the space camera and realizes the camera ground and on-orbit micro-vibration test at the same time. The image movement measurement channel and the normal imaging channel can work at the same time and share the main optical reflection element, thereby improving the accuracy of image movement measurement. (2) The present invention provides a space camera micro-vibration image shift measurement system and method, which uses a visible high frame rate CMOS detector to perform high-frequency image acquisition and realizes the Fourier transform of image shift from the time domain to the frequency domain; (3) The present invention provides a space camera micro-vibration image shift measurement system and method, which combines the traditional micro-vibration measurement method and adopts the method of direct image shift measurement combined with acceleration measurement simulation to evaluate the final image shift amount and complete the image shift amount measurement of the normal imaging channel. Attached Figure Description

[0009] Figure 1 This is a layout diagram of the optical system for the camera's infrared imaging channel and image shift measurement channel; Figure 2 This is a schematic diagram of the infrared imaging optical path of the camera; Figure 3 This is a schematic diagram of the ground test status of the space camera micro-vibration image motion measurement system; Figure 4 This is a schematic diagram of the on-orbit testing status of the space camera micro-vibration image displacement measurement system; Figure 5 It is a single-frame image formed by the focal plane of the ground micro-vibration test state image shift measurement channel; Figure 6 This is an example diagram of the time-domain curve of the image shift in the image shift measurement channel after calculation; Figure 7 This is an example graph of the frequency domain curve of the image shift in the image shift measurement channel after calculation. Detailed Implementation

[0010] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0011] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0012] like Figure 1 and Figure 2 As shown, a space camera optical system typically consists of primary, secondary, tertiary, and refracting primary optical reflective elements, relay optical reflective or transmissive elements, and a focal plane detector. Since the optical axis change caused by camera micro-vibrations is mainly affected by the angle change of the reflective elements, while the influence of the transmissive elements is relatively negligible, the construction of a micro-vibration image shift measurement system mainly considers the influence of the reflective mirrors.

[0013] like Figure 1As shown, the space camera micro-vibration image displacement measurement system of the present invention includes a laser light source, a light source angle adjustment device, optical components for the image displacement measurement channel, a focal plane detector for the image displacement measurement channel, a ground image acquisition device, and a ground analysis and processing system. The laser light source, light source angle adjustment device, ground image acquisition device, and ground analysis and processing system are only used in ground measurement mode; the remaining components are integrated with the camera and serve as part of the camera, enabling micro-vibration measurements both on the ground and in orbit. In in-orbit measurement mode, captured scene images can be directly extracted for image displacement calculation.

[0014] In the space camera micro-vibration image shift measurement system, the optical path of the image shift measurement channel and the normal imaging channel are partially shared. It uses the sub-aperture of the normal imaging channel, with the primary, secondary, folding, third, and fourth mirrors serving as reflectors (primary optical reflective elements), shared by both channels. The normal imaging channel consists of an infrared folding mirror, an infrared lens group, and an infrared focal plane detector. The image shift measurement channel, on the other hand, consists of an image shift switching mirror, an image shift folding mirror, an image shift lens group, and an image shift focal plane detector. The image shift switching mirror and the image shift folding mirror are reflectors. The image shift switching mirror is in a retracted state during normal imaging. During image shift measurement, it cuts into the optical path between the four mirrors and the infrared folding mirror, introducing light into the image shift measurement channel. The image shift switching mirror mechanism and the image shift folding mirror are mounted on the support structure of the primary optical reflective element, reflecting the micro-vibration of the primary optical reflective element. The image shift lens group and focal plane detector are mounted on the support structure of the infrared lens group.

[0015] The focal plane detector in the image shift measurement channel and the focal plane detector in the infrared imaging system have the same pixel resolution. Therefore, the angle change of the shared reflective optical element in the main optics has the same effect on the image shift in both channels. Based on the sensitivity matrix of the effect of the angle change of different optical elements in the optical system on the image shift, and the relative acceleration relationship of the non-shared optical elements, the image shift from the measured image shift in the image shift measurement channel to the image shift in the imaging channel is calculated.

[0016] Table 1. Relationship between angular changes of various optical components and image shift.

[0017] Based on Table 1 above, the relationships between the image shift of the two channels and the angle change of the optical components are as follows: P 成像 =θ1 / Δ1±θ2 / Δ2±θ3 / Δ3±θ4 / Δ4±θ5 / Δ5±θ6 / Δ6; P 像移 =θ1 / Δ1±θ2 / Δ2±θ3 / Δ3±θ4 / Δ4±θ5 / Δ5±θ7 / Δ7±θ8 / Δ8; In the formula, P 成像 and P 像移θ1, θ2, ..., θ8 represent the focal plane pixel movement (in pixels) for the normal imaging channel and the image shift measurement channel, respectively. θ1, θ2, ..., θ8 represent the angular changes (in inches) of each reflecting optical element, such as the primary mirror and secondary mirror. Δ1, Δ2, ..., Δ8 represent the vibration sensitivity (i.e., the angular change of the reflecting optical element when the focal plane detector image shifts by 1 pixel) of each reflecting optical element, and are fixed values. This can be further converted to: P 成像 =P 像移 θ7 / Δ7 θ8 / Δ8±θ6 / Δ6.

[0018] P 像移 The measured values ​​are obtained by solving the laser spot image. For example... Figure 3 As shown, the ground-based micro-vibration test is conducted using a highly stable laser light source, which is installed at the top of the lens support frame via a light source angle adjustment device. The camera installation boundary conditions should simulate the actual on-orbit conditions. Micro-vibration acceleration measurement sensors are attached to the infrared folding mirror, image shift switching mirror, and image shift folding mirror. Before measurement begins, the image shift switching mirror is inserted into the optical path between the four mirrors and the infrared folding mirror. The camera's image shift measurement channel can then be powered on to generate an image, which is the laser spot. Before the formal test, the environmental background noise is first tested, i.e., the image shift of the image shift measurement channel is sampled without the introduction of a micro-vibration excitation source. Subsequently, micro-vibration excitation is applied to the space camera or the entire satellite, and the image shift of the image shift measurement channel is tested again. The image shift of the image shift measurement channel without the introduction of a micro-vibration excitation source is subtracted to obtain the image shift P of the image shift measurement channel. 像移 Simultaneously, the acceleration response curves of three key components—the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror—were obtained.

[0019] When determining the image shift amount of the image shift measurement channel with / without introducing a micro-vibration excitation source, a laser source enters the camera from the light inlet at the top of the lens support frame. The image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, introducing the light into the image shift measurement channel, and finally imaging it onto the focal plane detector of the image shift measurement channel. Ground-based image acquisition equipment samples the focal plane image of the image shift measurement channel at a high frame rate and stores it in a time series. Then, a ground-based analysis and processing system reads the stored images, calculates the image shift changes, and obtains discrete data of the image position changing over time, i.e., x(t) and y(t). Subsequently, Fourier transforms are performed to obtain the image shift spectrum data, i.e., x(f) and y(f), thus revealing the magnitude of the image shift amount of the image shift measurement channel at different characteristic frequencies. Figure 5 This shows a single-frame image formed by the focal plane of the image displacement measurement channel during ground micro-vibration testing. Figure 6 An example graph showing the time-domain curve of the image shift in the image shift measurement channel after calculation is shown; Figure 7 An example graph showing the frequency domain curve of the image shift in the image shift measurement channel after calculation is provided.

[0020] θ6, θ7, and θ8 were determined using the finite element method: A finite element model of a space camera with optical components for the image shift measurement channel and a focal plane detector for the image shift measurement channel was established. By applying an excitation source and combining the measured acceleration responses of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror, the finite element model was corrected so that the simulated acceleration responses of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror were less than a set threshold compared to the measured results. This yielded the simulated values ​​θ6', θ7', and θ8' for θ6, θ7, and θ8. Therefore, P 成像 The calculated maximum value can be obtained according to P. 成像 =P 像移 +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6.

[0021] like Figure 4 As shown, during the on-orbit micro-vibration test, the image shift switching mirror is inserted into the optical path between the four mirrors and the infrared folding mirror. The image shift measurement channel is activated, images of the ground scene are formed, and high-frequency sampling is performed. After calculation, the image shift P of the image shift measurement channel can be obtained. 像移 Using P 成像 =P 像移 With +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 and the known θ6', θ7', and θ8', the image shift of the normal imaging channel is obtained.

[0022] The image motion measurement channel is a visible light imaging channel, which uses a visible CMOS high frame rate detector and can achieve an imaging frame rate of 2000Hz.

[0023] Laser light sources should be selected with small spot size, stable mode, and small divergence angle. Light sources with adjustable spot size and brightness are preferred to avoid excessively large imaging area or image saturation, which could affect the accuracy of the algorithm.

[0024] According to the working principle of the measurement system of the present invention, when designing the image shift measurement channel, the same common optical path reflective element should be used as much as possible with the normal imaging channel, and as few reflective elements should be set after the beam splitting path. The focal planes of the two channels should be close to each other and have high connection stiffness.

[0025] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0026] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A space camera micro-vibration image displacement measurement system, characterized in that, include: Laser source, source angle adjustment device, optical components of image shift measurement channel, focal plane detector of image shift measurement channel, ground image acquisition equipment and ground analysis and processing system; The optical components of the image shift measurement channel include a primary optical reflective element, an image shift switching mirror, an image shift folding mirror, and an image shift lens group. The primary optical reflective element is the same as that in the normal imaging channel of a space camera. In the optical path, the primary mirror, secondary mirror, folding mirror, third mirror, and fourth mirror are arranged in sequence. After the primary optical reflective element in the normal imaging channel, the infrared folding mirror, infrared lens group, and infrared focal plane detector are arranged in sequence. The image shift switching mirror and the image shift folding mirror are reflective mirrors. The image shift switching mirror is in a retracted state during normal imaging. During image shift measurement, it cuts into the optical path between the fourth mirror and the infrared folding mirror, introducing light into the image shift measurement channel. After passing through the image shift folding mirror and the image shift lens group, the light is imaged on the focal plane detector of the image shift measurement channel. The laser source, source angle adjustment device, ground image acquisition equipment, and ground analysis and processing system are only used for ground micro-vibration testing. The optical components of the image shift measurement channel and the focal plane detector of the image shift measurement channel are integrated with the space camera as a component of the camera and are used for ground and on-orbit micro-vibration testing. Under ground-based micro-vibration testing conditions, the laser source serves as the ground-based light source. The laser light enters the space camera through the light inlet at the top of the lens support frame. An image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, guiding the light into the image shift measurement channel and imaging it onto the focal plane detector of the image shift measurement channel. The ground-based image acquisition equipment samples the focal plane image of the image shift measurement channel and stores it in a time sequence. The ground-based analysis and processing system reads the stored image and determines the image shift P at the characteristic frequency of the image shift measurement channel. 像移 The ground analysis and processing system uses finite element analysis to determine the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation. Based on P... 成像 =P 像移 +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 determines the displacement of the normal imaging channel of the space camera, where Δ6, Δ7, and Δ8 are the vibration sensitivities of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror, respectively. Under on-orbit micro-vibration testing conditions, the image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, imaging the ground scene onto the focal plane detector of the image shift measurement channel. After sampling by the on-board analysis and processing system, the image shift P at the characteristic frequency of the image shift measurement channel is determined. 像移 Using P 成像 =P 像移 With +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 and the known θ6', θ7', and θ8', the image shift of the normal imaging channel is obtained.

2. The space camera micro-vibration image shift measurement system according to claim 1, characterized in that, The image shift switching mirror mechanism and the image shift folding mirror are mounted on the main optical reflective element support structure to reflect the micro-vibration of the main optical reflective element; the image shift lens group and the focal plane detector are mounted on the support structure of the infrared lens group.

3. The space camera micro-vibration image shift measurement system according to claim 1, characterized in that, The ground analysis and processing system determines the image shift P of the image shift measurement channel at the characteristic frequency. 像移 At the same time, images stored in the ground analysis and processing system are read when no micro-vibration excitation source is introduced and when it is introduced. The image shift change is calculated separately to obtain discrete data of image position change over time. Then, Fourier transform is performed to obtain image shift spectrum data, and the image shift amount of the image shift measurement channel at the characteristic frequency when no micro-vibration excitation source is introduced and when it is introduced is obtained. The image shift amount of the image shift measurement channel when no micro-vibration excitation source is introduced is subtracted from the image shift amount of the image shift measurement channel at the characteristic frequency when micro-vibration excitation source is introduced to obtain the image shift P of the image shift measurement channel. 像移 .

4. The space camera micro-vibration image shift measurement system according to claim 1, characterized in that, The ground analysis and processing system determines the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation using the finite element method. The system establishes a finite element model of a space camera with optical components for the image shift measurement channel and a focal plane detector for the image shift measurement channel. By applying an excitation source and combining the measured acceleration responses of the infrared folding mirror, image shift switching mirror, and image shift folding mirror, the system corrects the finite element model, ensuring that the simulated acceleration responses of the infrared folding mirror, image shift switching mirror, and image shift folding mirror are less than a set threshold compared to the measured results. This yields the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation.

5. The space camera micro-vibration image shift measurement system according to claim 1, characterized in that, The image shift measurement system is a visible light imaging system that uses a visible CMOS high frame rate detector.

6. A method for measuring image shift due to micro-vibrations in a space camera, characterized in that, The space camera micro-vibration image shift measurement system according to any one of claims 1 to 5 is characterized in that it comprises: Under ground-based micro-vibration testing conditions, the laser source serves as the ground-based light source. The laser light enters the space camera through the light inlet at the top of the lens support frame. An image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, guiding the light into the image shift measurement channel and imaging it onto the focal plane detector of the image shift measurement channel. The ground-based image acquisition equipment samples the focal plane image of the image shift measurement channel and stores it in a time sequence. The ground-based analysis and processing system reads the stored image and determines the image shift P at the characteristic frequency of the image shift measurement channel. 像移 The ground analysis and processing system uses finite element analysis to determine the angular changes θ6', θ7', and θ8' of the infrared folding mirror, image shift switching mirror, and image shift folding mirror after applying micro-vibration excitation. Based on P... 成像 =P 像移 +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 determines the displacement of the normal imaging channel of the space camera, where Δ6, Δ7, and Δ8 are the vibration sensitivities of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror, respectively. Under on-orbit micro-vibration testing conditions, the image shift switching mirror cuts into the optical path between the four mirrors and the infrared folding mirror, imaging the ground scene onto the focal plane detector of the image shift measurement channel. After sampling by the on-board analysis and processing system, the image shift P at the characteristic frequency of the image shift measurement channel is determined. 像移 Using P 成像 =P 像移 With +θ7' / Δ7+θ8' / Δ8+θ6' / Δ6 and the known θ6', θ7', and θ8', the image shift of the normal imaging channel is obtained.

7. The method for measuring micro-vibration image shift of a space camera according to claim 6, characterized in that, Under ground-based micro-vibration testing conditions, micro-vibration acceleration measurement sensors are attached to the infrared folding mirror, image shift switching mirror, and image shift folding mirror. Before the formal test, the environmental background noise is first measured, i.e., the image shift of the image shift measurement channel is sampled without the introduction of a micro-vibration excitation source. Then, micro-vibration excitation is applied to the space camera or the entire satellite, and the image shift of the image shift measurement channel is measured again. The image shift P of the image shift measurement channel is obtained by subtracting the image shift of the image shift measurement channel without the introduction of a micro-vibration excitation source. 像移 Simultaneously, the acceleration response curves of three key components—the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror—were obtained, which were used by the finite element method to determine the angular changes of the infrared folding mirror, the image shift switching mirror, and the image shift folding mirror after the application of micro-vibration excitation.

Images