On-orbit tuning method for space remote sensing cameras

Abstract

The present invention relates to the technical field of on-orbit adjustment of space remote sensing cameras, and in particular to an on-orbit optimization method for a space remote sensing camera. First, based on the area array working mode of a time-delayed integrated linear array detector, the space remote sensing camera is tested in a stationary state after its attitude is stabilized. The secondary mirror position is coarsely adjusted by stargazing. When the obtained diffuse spot size and shape are close to a circular diffuse spot size and the diffuse spot size reaches a minimum, the focus position is coarsely adjusted. Then, the secondary mirror position and the focus position are finely adjusted based on a knife-edge target on the ground. Finally, the time-delayed integrated linear array detector is tested in a push-scan state. After confirming that the TDI direction and image motion speed are correct, fine on-orbit optimization is performed. By setting reasonable optimization steps, the present invention can effectively improve optimization efficiency, thereby saving optimization time and reducing the consumption of on-orbit resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of on-orbit adjustment of space remote sensing cameras, and in particular relates to an on-orbit optimization method for a space remote sensing camera based on a time-delayed integrated linear array detector. Background Art

[0002] After launch into orbit, space remote sensing cameras operate in the microgravity environment of space. Throughout their development, they are inevitably affected by ground gravity. As the aperture and focal length of space remote sensing cameras increase, the adverse effects of gravity on the assembly and testing of optical systems are greatly amplified, making it increasingly difficult to ensure the position accuracy of mirrors in large-aperture, long-focal-length optical systems. When a space remote sensing camera reaches optimal performance through assembly and testing under ground gravity conditions, the optical system already includes gravitational deformation of the mirrors, their supporting structures, and the camera body. During launch, the camera is subject to vibration and impact, and after entering orbit, this gravitational deformation is released in the microgravity environment of space, causing the position of each mirror in the optical system to change. This, in turn, generates certain wave aberrations in the optical system, impacting the on-orbit imaging quality of the space remote sensing camera.

[0003] Current solutions to gravity deformation primarily rely on ground-based gravity unloading. However, this method struggles to completely eliminate the effects of gravity deformation. Furthermore, the gravity unloading process can easily induce localized stress in space remote sensing cameras, making it difficult to guarantee the effectiveness of gravity unloading. Therefore, new methods are needed to address the technical challenges of gravity-induced difficulties in the assembly and inspection of large-aperture space remote sensing cameras. In addition to the effects of ground-based gravity, environmental factors such as vibration and shock during launch, as well as on-orbit temperature fluctuations, can significantly impact space remote sensing cameras. These factors can cause post-orbit misalignment wave aberrations to exceed design requirements, impacting the camera's on-orbit imaging quality. Due to the random nature of these factors, simulation analysis can only be performed by estimating the extremes of misalignment.

[0004] The invention patent with publication number CN113093361A proposes a method for on-orbit adjustment of a space camera. The ground processing steps of the space camera before launch include: (1) the temperature of the installation and experiment is kept consistent with the on-orbit design temperature; (2) reverse loading of gravity is performed, and the influence of gravity on the position of the optical elements of the telephoto camera is analyzed through system simulation, and the adjustment range of the secondary mirror is estimated; (3) for the two postures of 0° and 180° when the camera is on the ground, the adjustment amount of the secondary mirror position caused by the influence of gravity is quantitatively measured; (4) before the camera is launched, the adjustment direction and adjustment amount of the secondary mirror position are pre-set according to the measurement results of the adjustment amount. The ground verification steps of the secondary mirror adjustment include: (1) placing the camera according to the on-orbit posture, adjusting the ambient temperature to the on-orbit design temperature, measuring the wave aberration of the optical system, and adjusting the position of the secondary mirror to the optimal state; (2) flipping the camera 180 degrees based on the on-orbit posture, adjusting the ambient temperature to the on-orbit design temperature, measuring the wave aberration of the optical system, and adjusting the position of the secondary mirror. The position adjustment makes the system wave aberration reach the optimal state; the direction and range of the secondary mirror position adjustment are determined by this scheme; the steps of adjusting the secondary mirror on track include: (1) focusing by the climbing method to obtain the optimal focal plane position, that is, the focal plane position when the transfer function is maximum; (2) adjusting the secondary mirror position in the X direction to obtain the secondary mirror position in the X direction when the transfer function is maximum; (3) adjusting the secondary mirror position in the Y direction to obtain the secondary mirror position in the Y direction when the transfer function is maximum; (4) rotating the secondary mirror angle in the X direction to obtain the secondary mirror rotation angle in the X direction when the transfer function is maximum; (5) rotating the secondary mirror angle in the Y direction to obtain the secondary mirror rotation angle in the Y direction when the transfer function is maximum; at the same time, the judgment criteria for the optimal position and rotation angle on track are introduced: shooting the target laid on the ground, performing fine image shift matching, performing real-time imaging of the ground target, adjusting the position of the secondary mirror, and calculating the transfer function value through target image analysis at different secondary mirror positions and rotation angles. The secondary mirror position and angle corresponding to the maximum value of the transfer function are the optimal position and rotation angle of the secondary mirror on track.

[0005] However, the patent does not take into account that image shift mismatch, defocus and wave aberration may all cause image blur. Specific means and judgment criteria are needed to separate the three and find out the causes of image blur in order to achieve the optimal on-orbit adjustment of the space remote sensing camera. Summary of the Invention

[0006] In view of this, the present invention aims to provide an on-orbit optimization method for a space remote sensing camera to solve the problem that the patent publication number CN113093361A cannot achieve on-orbit optimal state optimization of a space remote sensing camera.

[0007] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0008] A method for on-orbit tuning of a space remote sensing camera. The space remote sensing camera includes a camera controller, an optical system, a time-delayed integrated linear array detector, and an imaging processing unit. The optical system includes a focusing mechanism and a secondary mirror adjustment mechanism. The camera controller is used to receive control instructions from the ground, control the focusing mechanism and the secondary mirror adjustment mechanism, set the operating mode of the time-delayed integrated linear array detector, and set the operating mode of the imaging processing unit.

[0009] The on-orbit tuning method includes the following steps:

[0010] S1: Set the working mode of the time delay integration linear array detector to the area array working mode through the camera controller, and use the secondary mirror adjustment mechanism to perform coarse adjustment of the secondary mirror through star observation to obtain the optimal secondary mirror position range;

[0011] S2: Maintaining the area array working mode of the time delay integration linear array detector unchanged, after the secondary mirror coarse adjustment is completed, perform coarse focusing using the focusing mechanism through star observation to obtain the optimal focusing position range;

[0012] S3: Maintaining the time delay integration linear array detector in planar array mode, perform a static modulation transfer function test on a knife-edge target on the ground, and fine-tune the secondary mirror within the optimal secondary mirror position range to obtain the secondary mirror position corresponding to the maximum static modulation transfer function.

[0013] S4: Maintaining the area array operating mode of the time delay integration linear array detector unchanged, perform a static modulation transfer function test on a knife-edge target on the ground, and fine-tune the focus position within the optimal focus position range to obtain the focus position corresponding to the maximum static modulation transfer function;

[0014] S5: The camera controller is used to set the working mode of the time delay integration linear array detector to the linear array working mode. A dynamic modulation transfer function test is performed by observing a knife-edge target on the ground. The dynamic modulation transfer function values ​​of the two TDI directions are compared, and the direction with the larger dynamic modulation transfer function value is taken as the TDI direction.

[0015] S6: Maintaining the linear array working mode of the time delay integration linear array detector unchanged, a dynamic modulation transfer function test is performed on the edge target on the ground. By performing positive and negative deviations on the image motion velocity, the velocity corresponding to the maximum value of the dynamic modulation transfer function is taken as the image motion velocity;

[0016] S7: If, in the linear array working mode, the image in the vertical track direction is clear, while the image in the along track direction is blurred, and in the area array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the image blur is caused by opposite TDI directions or image motion velocity mismatch; if, in the linear array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the TDI direction is correct or the image motion velocity is matched; if, in the area array working mode, the images in both the along track and vertical track directions are blurred, then it is determined that the image blur is caused by additional factors.

[0017] Furthermore, the working mode of the time delay integration linear array detector is set to the area array working mode through the camera controller, and a static modulation transfer function test is performed on the edge target on the ground through star observation to evaluate the optimal secondary mirror position and focal plane position.

[0018] Furthermore, when the imaging processing unit is in the normal working mode, the image data is conditioned and the conditioned image data is output; when the imaging processing unit is in the star observation tuning mode, the diffuse light spots of the star point target are counted, the center of the star point target is used as the coordinate origin, the grayscale value in the diffuse light spot is multiplied by the distance between the diffuse light spot and the coordinate origin, and the calculation result is fed back to the camera controller; when the imaging processing unit is in the ground observation tuning mode, the dynamic modulation transfer function and the static modulation transfer function are calculated based on the knife edge method, and the calculation result is fed back to the camera controller.

[0019] Furthermore, additional factors are defocus or wavefront aberration exceeding a threshold.

[0020] Furthermore, the constraints between the operating wavelength λ, focal ratio F, and pixel size a of the optical system are as follows: .

[0021] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0022] (1) Improve tuning efficiency by setting reasonable tuning steps, thereby saving tuning time and reducing the consumption of on-orbit resources;

[0023] (2) By switching between the area array and linear array working modes of the time delay integration linear array detector, it is possible to quickly determine whether there is an image shift mismatch, thereby quickly locating the tuning problem;

[0024] (3) By switching between different working states of the imaging processing unit, relevant results can be calculated quickly on orbit. There is no need to wait for the data to be transmitted to the ground for processing and calculation before the next adjustment operation. This increases the cycle speed of the tuning and reduces the cycle period, thereby improving the tuning efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 2 is a schematic structural diagram of a space remote sensing camera according to an embodiment of the present invention.

[0027] Description of reference numerals: camera controller 1 , optical system 2 , time-delay integration linear array detector 3 and imaging processing unit 4 . DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0033] The present invention provides an on-orbit optimization method for a space remote sensing camera. The structure of the space remote sensing camera is as follows: Figure 1 As shown, the space remote sensing camera includes a camera controller 1, an optical system 2, a time-delayed integrated linear array detector 3 and an imaging processing unit 4; wherein, the optical system 2 includes a focusing mechanism and a secondary mirror adjustment mechanism, and the camera controller 1 is used to receive control instructions from the ground and perform different operation controls, including controlling the focusing mechanism and the secondary mirror adjustment mechanism to realize secondary mirror adjustment and focusing, setting the working mode of the time-delayed integrated linear array detector and setting the working mode of the imaging processing unit.

[0034] In a specific embodiment, the camera controller 1 adopts an architecture based on DSP+FPGA and stepper motor; the optical system 2 adopts an off-axis three-mirror adjustment secondary mirror form; the time-delayed integral linear array detector 3 adopts a focal plane component based on a TDICCD detector or a TDICMOS detector; and the imaging processing unit 4 is implemented using an FPGA from Xilinx or Fudan Microelectronics.

[0035] The operating wavelength λ, focal ratio F, and pixel size a of the optical system 2 need to satisfy the following constraints:

[0036] .

[0037] The purpose of this constraint is to ensure that the size of the diffuse spot is large enough, at least larger than 3 pixels. If the size of the diffuse spot is too small, the accuracy of calculating the centroid position of the spot will be reduced. If the size of the diffuse spot is only one pixel, the centroid position of the spot cannot be subdivided. If the size of the diffuse spot is two pixels, the subdivision accuracy is low.

[0038] The purpose of the present invention is to achieve the separation of image motion mismatch, defocus, and wavefront aberration. The time-delayed integrated linear array detector 3 can avoid the effects of image motion mismatch in the area array operating mode. By comparing the area array operating mode with the linear array operating mode, it is possible to determine whether image motion mismatch exists. Defocus and wavefront aberration can be separated through stargazing. If the secondary mirror is adjusted in the stargazing mode, the diffuse spot size of the star point can be reduced and the shape of the star point more symmetrical, then wavefront aberration still exists. If the focus is adjusted in the stargazing mode, the size of the star point can be made smaller, then defocus exists.

[0039] The on-orbit tuning method of a space remote sensing camera provided by the present invention comprises the following steps:

[0040] S1: Set the working mode of the time delay integration linear array detector to the area array working mode through the camera controller, and use the secondary mirror adjustment mechanism to perform coarse adjustment of the secondary mirror through star observation to obtain the optimal secondary mirror position range.

[0041] When adjusting the secondary mirror in stargazing mode, if the diffuse spot size of the star becomes smaller and the shape of the star becomes more symmetrical, then wave aberration still exists. During the secondary mirror adjustment process, record the position where the diffuse spot size of the star is smallest and the shape of the star is most symmetrical. This is considered the optimal secondary mirror position.

[0042] S2: Maintain the area array working mode of the time delay integral linear array detector unchanged. After the secondary mirror coarse adjustment is completed, perform coarse focusing using the focusing mechanism through star observation to obtain the optimal focusing position range.

[0043] The array working mode based on the time-delayed integral linear array detector ensures that the space remote sensing camera is tested in a static state after its posture is stable. The secondary mirror state is roughly adjusted by stargazing. When the obtained diffuse spot size is close to circular and the diffuse spot size reaches the minimum, the coarse focusing of the optical system is started.

[0044] If adjusting the focus in stargazing mode makes the star point smaller, then there is defocus. During the focusing process, record the position where the star point diffuse spot size is the smallest, which is the optimal focus position.

[0045] S3: Maintaining the array working mode of the time delay integration linear array detector unchanged, perform a static modulation transfer function test on the edge target on the ground, fine-tune the secondary mirror within the optimal secondary mirror position range, and obtain the secondary mirror position corresponding to the maximum static modulation transfer function.

[0046] In the stargazing mode, a large range of secondary mirror position adjustment is performed. After obtaining the optimal position of the secondary mirror coarse adjustment, the secondary mirror position is finely adjusted. The adjustment range is less than 1 / 10 of the coarse adjustment range, and the modulation amount each time is less than 1 / 10 of the coarse adjustment. After each adjustment, a static modulation transfer function test is performed, and the position of the maximum static modulation transfer function is recorded, which is regarded as the optimal secondary mirror position.

[0047] S4: Maintaining the area array working mode of the time delay integration linear array detector unchanged, perform a static modulation transfer function test on the edge target on the ground, fine-tune the focus position within the optimal focus position range, and obtain the focus position corresponding to the maximum static modulation transfer function.

[0048] Perform a wide range of focal adjustments in Stargazing mode. After obtaining the optimal coarse focus position, fine-tune the focus position. The adjustment range should be less than 1 / 10 of the coarse adjustment range, and the modulation amount should be less than 1 / 10 of the coarse adjustment. Perform a static modulation transfer function test after each adjustment. The position with the maximum static modulation transfer function is recorded as the optimal focal position.

[0049] The working mode of the time delay integration linear array detector is set to the planar array working mode through the camera controller, and a static modulation transfer function test is performed on the edge target on the ground through star observation. When the static modulation transfer function corresponding to the secondary mirror position is the largest, it is considered to be the optimal secondary mirror position; when the static modulation transfer function corresponding to the focal plane position is the largest, it is considered to be the optimal focal plane position.

[0050] S5: The working mode of the time delay integration linear array detector is set to the linear array working mode through the camera controller, and a dynamic modulation transfer function test is performed by observing the edge target on the ground. By comparing the dynamic modulation transfer function values ​​of the two TDI directions, the direction with the larger dynamic modulation transfer function value is taken as the TDI direction.

[0051] The two TDI directions refer to the same direction as the set instruction and the opposite direction as the set instruction. By comparing the imaging effects of the two TDI directions, it is determined whether there is a TDI direction error.

[0052] S6: Maintaining the linear array working mode of the time delay integration linear array detector unchanged, a dynamic modulation transfer function test is performed on the edge target observation on the ground. By performing positive and negative deviations on the image motion speed, the speed corresponding to the maximum value of the dynamic modulation transfer function is used as the image motion speed.

[0053] Achieving a high-dynamic modulation transfer function requires image motion matching, meaning that the charge transfer line frequency matches the image motion velocity on orbit. The image motion velocity is calculated based on the satellite's position and attitude in space. This calculation is complex, and the satellite's position and attitude measured on orbit may differ, leading to a discrepancy between the calculated line frequency and the actual image motion velocity. Therefore, to achieve a higher dynamic modulation transfer function and optimal imaging, a positive and negative deviation is applied to the line frequency corresponding to the calculated image motion velocity. This means that, based on the line frequency corresponding to the calculated image motion velocity, a range of positive and negative deviations are used for comparative testing to determine whether the resulting imaging effect improves.

[0054] For example: negative bias 60%, negative bias 50%, negative bias 40%, negative bias 30%, negative bias 20%, negative bias 10%, negative bias 5%, calculated value, positive bias 5%, positive bias 10%, positive bias 20%, positive bias 30%, positive bias 40%, positive bias 50%, positive bias 60%.

[0055] S7: If, in the linear array working mode, the image in the vertical track direction is clear, while the image in the along track direction is blurred, and in the area array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the image blur is caused by opposite TDI directions or image motion velocity mismatch; if, in the linear array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the TDI direction is correct or the image motion velocity is matched; if, in the area array working mode, the images in both the along track and vertical track directions are blurred, then it is determined that the image blur is caused by additional factors.

[0056] The vertical track direction refers to the scanning direction perpendicular to the space track or perpendicular to the flight direction; the along track direction refers to the scanning direction parallel to the space track or the flight direction.

[0057] The imaging effects in two dimensions are used to determine whether the TDI direction is opposite or the image motion speed is mismatched:

[0058] When the time delay integration linear array detector is in linear array mode, the image in the vertical direction is clear (dynamic modulation transfer function is high), but the image in the along-track direction is blurred (dynamic modulation transfer function is low), and when the time delay integration linear array detector is in area array mode, the image in both the along-track and vertical directions is clear (static modulation transfer function is high), it is determined that the image blur is caused by opposite TDI directions or image motion velocity mismatch;

[0059] When the time delay integration linear array detector is in the linear array working mode, the images in the along-track direction and the perpendicular-track direction are both clear (dynamic modulation transfer function is high), then it is determined that the TDI direction is correct or the image motion speed is matched, and there is no possibility of the TDI direction being opposite or the image motion speed being mismatched;

[0060] When a time delay integration linear array detector operates in area array mode and images are blurred in both the along-track and cross-track directions (with low static modulation transfer functions), the image blur is determined to be caused by factors other than TDI direction reversal or image motion velocity mismatch. These factors can be defocus or excessive wavefront aberration exceeding the threshold.

[0061] It should be noted that imaging in the area array working mode belongs to the static modulation transfer function, while imaging in the linear array working mode belongs to the dynamic modulation transfer function.

[0062] By switching between the area array working mode and the linear array working mode of the time delay integral linear array imaging focal plane, it is possible to quickly determine whether there is an image motion mismatch, thereby quickly locating the tuning problem.

[0063] According to different working modes of the imaging processing unit, the different working states of the imaging processing unit are switched:

[0064] When the imaging processing unit is in a normal working mode, the image data is conditioned and the conditioned image data is output;

[0065] When the imaging processing unit is in the stargazing tuning mode, the diffuse light spots of the star point target are counted. The center of the star point target is used as the coordinate origin. The grayscale value within the diffuse light spot of the star point target is multiplied by the distance between the diffuse light spot of the star point target and the coordinate origin of the diffuse light spot of the star point target, and the calculation result is fed back to the camera controller;

[0066] When the imaging processing unit is in the ground object optimization mode, the modulation transfer function is calculated based on the knife edge method, and the calculation result is fed back to the camera controller.

[0067] By switching between different working states of the imaging processing unit, relevant results can be calculated quickly on orbit. There is no need to wait for the data to be transmitted to the ground for processing and calculation before making the next adjustment operation. This increases the cycle speed of the tuning and reduces the cycle period, thereby improving the tuning efficiency.

[0068] The present invention can effectively improve the optimization efficiency by setting reasonable optimization steps, thereby saving optimization time and reducing the consumption of on-orbit resources.

[0069] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0070] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for on-orbit tuning of a space remote sensing camera, wherein the space remote sensing camera comprises a camera controller, an optical system, a time-delayed integrated linear array detector, and an imaging processing unit. The optical system comprises a focusing mechanism and a secondary mirror adjustment mechanism. The camera controller is configured to receive control instructions from the ground, control the focusing mechanism and the secondary mirror adjustment mechanism, set the operating mode of the time-delayed integrated linear array detector, and set the operating mode of the imaging processing unit. The method is characterized in that: The on-orbit tuning method includes the following steps: S1: Set the working mode of the time delay integration linear array detector to the area array working mode through the camera controller, and use the secondary mirror adjustment mechanism to perform coarse adjustment of the secondary mirror through star observation to obtain the optimal secondary mirror position range; S2: Maintaining the area array working mode of the time delay integration linear array detector unchanged, after the secondary mirror coarse adjustment is completed, perform coarse focusing using the focusing mechanism through star observation to obtain the optimal focusing position range; S3: Maintaining the time delay integration linear array detector in planar array mode, perform a static modulation transfer function test on a knife-edge target on the ground, and fine-tune the secondary mirror within the optimal secondary mirror position range to obtain the secondary mirror position corresponding to the maximum static modulation transfer function. S4: Maintaining the area array operating mode of the time delay integration linear array detector unchanged, perform a static modulation transfer function test on a knife-edge target on the ground, and fine-tune the focus position within the optimal focus position range to obtain the focus position corresponding to the maximum static modulation transfer function; S5: The camera controller sets the working mode of the time delay integration linear array detector to the linear array working mode, performs a dynamic modulation transfer function test on a knife-edge target on the ground, compares the dynamic modulation transfer function values ​​in two TDI directions, and takes the direction with the larger dynamic modulation transfer function value as the TDI direction; the two TDI directions are the same direction as the setting instruction and the opposite direction to the setting instruction respectively; S6: Maintaining the linear array working mode of the time delay integration linear array detector unchanged, a dynamic modulation transfer function test is performed on the edge target on the ground. By performing positive and negative deviations on the image motion velocity, the velocity corresponding to the maximum value of the dynamic modulation transfer function is taken as the image motion velocity; S7: If, in the linear array working mode, the image in the vertical track direction is clear, while the image in the along track direction is blurred, and in the area array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the image blur is caused by opposite TDI directions or image motion velocity mismatch; if, in the linear array working mode, the images in both the along track and vertical track directions are clear, then it is determined that the TDI direction is correct or the image motion velocity is matched; if, in the area array working mode, the images in both the along track and vertical track directions are blurred, then it is determined that the image blur is caused by additional factors.

2. The on-orbit tuning method for a space remote sensing camera according to claim 1, characterized in that: The working mode of the time delay integration linear array detector is set to the area array working mode through the camera controller. The static modulation transfer function test of the edge target on the ground is performed by star observation to evaluate the optimal secondary mirror position and focal plane position.

3. The on-orbit tuning method for a space remote sensing camera according to claim 1, characterized in that: When the imaging processing unit is in normal working mode, the image data is conditioned and the conditioned image data is output; when the imaging processing unit is in star observation tuning mode, the diffuse light spots of the star point target are counted, the center of the star point target is used as the coordinate origin, the grayscale value in the diffuse light spot is multiplied by the distance between the diffuse light spot and the coordinate origin, and the calculation result is fed back to the camera controller; when the imaging processing unit is in ground observation tuning mode, the dynamic modulation transfer function and the static modulation transfer function are calculated based on the knife edge method, and the calculation result is fed back to the camera controller.

4. The on-orbit tuning method for a space remote sensing camera according to claim 1, characterized in that: Additional factors are defocus or wave aberration exceeding a threshold.

5. The on-orbit tuning method for a space remote sensing camera according to claim 1, characterized in that: The constraints between the operating wavelength λ, focal ratio F, and pixel size a of the optical system are: .

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