A pupil rotation and drift detection method for an anamorphic secondary mirror telescope

Abstract

The application discloses a pupil rotation and drift detection method for a deformable secondary mirror telescope, and belongs to the technical field of adaptive optics. The method comprises the following steps: when an adaptive optical system is open-loop, a specific positive and negative voltage sequence is loaded on a specific driver, the wavefront sensor sub-aperture slope output is recorded, the position of the powered driver is solved, the pupil rotation angle and the pupil center position are fitted, and high-precision detection of the pupil rotation and drift is realized; when the adaptive optical system is closed-loop, the deformable secondary mirror driver voltage and the wavefront sensor sub-aperture slope in a period of time are recorded, the correlation coefficient matrix is calculated after data preprocessing, the position of the specific driver is solved through the correlation coefficient matrix, the pupil rotation angle and the pupil center position are fitted, and online real-time detection of the pupil rotation and drift is realized. The application can improve the closed-loop stability of the adaptive optical system and can be used for adaptive optical closed-loop control of a telescope based on a deformable secondary mirror.

Description

Technical Field

[0001] This invention belongs to the field of adaptive optics technology, specifically relating to a method for detecting pupil plane rotation and drift in deformable secondary mirror telescopes, applicable to closed-loop control of adaptive optics deformable secondary mirrors. Background Technology

[0002] As astronomical observations advance towards fainter and more distant targets, large-aperture ground-based telescopes must rely on adaptive optics techniques to overcome the effects of atmospheric turbulence. Among these techniques, deformable secondary mirror technology has attracted significant attention due to its integrated design. It integrates the telescope's secondary mirror itself into an active optical surface with hundreds to thousands of actuators, replacing the traditional rear-mounted, separate deformable mirror. This design offers significant advantages: it greatly reduces the number of optical path components, thereby minimizing light loss and unwanted thermal radiation; simultaneously, it simplifies the optical path and improves system stability. This technology has been successfully applied to large telescopes such as the MMT, LBT, and VLT.

[0003] However, in telescopes equipped with altazimuth rigs, deformable secondary mirror technology faces a critical challenge: dynamic pupil rotation and drift. Because the overall optical structure of an altazimuth telescope continuously rotates relative to a fixed instrument platform (such as a focus-endurance platform) when tracking a target, the telescope's exit pupil experiences continuous rotation (pupil rotation) and drift (pupil drift) relative to the downstream wavefront sensor. This problem severely impacts the adaptive optics closed-loop system. Normal system operation relies on a precise and stable spatial mapping between the wavefront sensor sub-aperture and the deformable secondary mirror actuator, characterized by a response matrix. Dynamic changes in the pupil state directly disrupt this mapping. Continuing to use a statically calibrated response matrix will cause correction commands to be applied to incorrect actuators, failing to effectively compensate for atmospheric turbulence and introducing additional system aberrations, ultimately leading to closed-loop failure.

[0004] To address this problem, current mainstream solutions rely on hardware derotation, mainly falling into two categories: inserting a rotatable K-mirror into the optical path, or directly rotating the instrument platform carrying the wavefront sensor. However, these solutions have inherent drawbacks: they significantly increase the optical and mechanical complexity of the system, introducing additional error sources; they are costly and have stringent requirements for motion accuracy; most importantly, in many compact, modified, or budget-constrained systems, physical space or structural design limitations make it impossible to install such large rotating hardware. Meanwhile, existing software derotation methods are underdeveloped, typically used as hardware-assisted methods for slow correction, with purely software derotation methods rarely studied. None of these methods can meet the requirements for real-time, high-precision tracking and correction of dynamic targets.

[0005] Therefore, developing a purely software-based derotation method that is independent of large rotating hardware, especially suitable for compact or modified facilities, is crucial for expanding the application scenarios of adaptive optics technology for deformable secondary mirrors and improving its system reliability and observation efficiency. One of the most important aspects of this is achieving a high-precision, real-time online calculation method for pupil state detection. This invention presents an innovative solution to address this urgent need. Summary of the Invention

[0006] The technical problem this invention aims to solve is: how to acquire the current pupil state and determine whether rotation or drift has occurred in an adaptive optics system for a deformable secondary mirror telescope without adding other large derotation hardware. Since adaptive optics systems are typically equipped with a Shaker-Hartmann wavefront sensor to detect the wavefront, this sensor can be used to detect the slope output under different deformable secondary mirror driver voltages, achieving fast and efficient pupil state detection. When the adaptive optics system operates in open-loop mode, the deformable secondary mirror driver voltage can be manually applied; in closed-loop mode, the deformable secondary mirror driver voltage is the closed-loop voltage calculated from the control matrix.

[0007] In view of this, the present invention provides a method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope. The method obtains wavefront sensor slope data by energizing a specific driver of the deformable secondary mirror in an open loop, stores the voltage of the deformable secondary mirror and the slope of the wavefront sensor in a closed loop, and calculates the position of the specific driver to obtain the pupil plane state under the current telescope state, thereby improving the stability and accuracy of the closed loop of the deformable secondary mirror.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope includes:

[0010] Step S110: When the telescope adaptive optics system is open-loop, perform high-precision open-loop pupil rotation and pupil drift detection. First, apply a specific positive and negative voltage sequence to the pre-selected drivers on the deformable secondary mirror that are spatially distributed on the pupil. Then, collect the slope output of the Shaker-Hartmann wavefront sensor. Then, calculate the position of the pre-selected driver on the wavefront sensor based on the slope. Finally, fit the pupil rotation angle and the pupil center position.

[0011] Step S120: When the telescope adaptive optics system is closed, online closed-loop pupil rotation and pupil drift detection is performed. First, the voltage of the deformable secondary mirror driver and the slope of the Shaker-Hartmann wavefront sensor are synchronously acquired at each moment in the closed-loop state. Then, the data is preprocessed according to the system conditions. Next, the correlation coefficient matrix between the preprocessed deformable secondary mirror driver voltage and the wavefront sensor slope is solved. Based on the correlation coefficient matrix, the position of the pre-selected driver on the wavefront sensor is calculated. Finally, the pupil rotation angle and the pupil center position are fitted to obtain the results.

[0012] Step S130: Based on the telescope status and the changing status of the tracked target, first select the deformable secondary mirror control matrix calculated according to the theoretical pupil surface status or the previous measured matrix as the initial matrix. Then select open-loop pupil rotation and pupil drift detection or closed-loop pupil rotation and pupil drift detection, update the deformable secondary mirror control matrix according to the measured pupil surface status, and correct the error in the initial matrix.

[0013] The beneficial effects of this invention are as follows:

[0014] It achieves a completely software-based solution, eliminating the reliance on high-cost, highly complex rotating hardware (such as K-mirrors and rotating platforms), making it particularly suitable for compact or modified telescope systems with limited physical space that cannot accommodate such hardware, significantly reducing system cost, complexity, and assembly difficulty.

[0015] A hybrid detection architecture combining open-loop high-precision detection and closed-loop online detection is proposed, achieving both high accuracy and high real-time performance. Different detection methods can be employed for different observation states and targets.

[0016] A fast open-loop detection method based on sparse excitation and specific positive and negative voltage sequences is proposed. The number of drivers applying the excitation is only a single digit. For deformable mirrors with hundreds of drivers, the single detection time will be greatly shortened compared with the global response matrix measurement time, and the efficiency will be improved by tens to hundreds of times. Furthermore, the signal-to-noise ratio and solution robustness are effectively improved by orthogonal excitation.

[0017] A closed-loop online detection method based on high-pass filtering and correlation calculation is proposed. The closed-loop data stream is used for online correlation analysis, which realizes "unobtrusive" monitoring of pupil state without introducing additional disturbances or affecting normal observation.

[0018] The method fits the pupil rotation angle and pupil center using multiple actuator positions calculated from the slope data of the wavefront sensor. It has wide applicability and good adaptability to non-ideal conditions such as uneven light intensity of the wavefront sensor sub-aperture, changes in guide star brightness (such as sodium beacons), and atmospheric noise, ensuring the effectiveness of the method in the actual measurement environment. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the pupil plane rotation and drift detection method used in the deformable secondary mirror telescope of the present invention.

[0020] Figure 2 This is a schematic diagram of the deformable secondary mirror actuator, the theoretical arrangement of the sub-aperture of the Shaker-Hartmann wavefront sensor, and the open-loop pupil detection power-on actuator in this invention.

[0021] Figure 3 This invention provides a high-precision open-loop detection of the Hadamard positive and negative voltage sequences applied to the six deformable secondary mirror actuators.

[0022] Figure 4 This refers to the specified driver position obtained by inverse calculation of open-loop detection in this invention.

[0023] Figure 5 This refers to the specified driver position obtained by inverse calculation of closed-loop detection in this invention.

[0024] The meanings of the reference numerals in the figure are as follows: 1 is the sub-aperture, 2 is the actuator, 3 is the actuator excited in the open-loop detection method, 4 is the actuator position, 5 is the pupil center position, and 6 is the effective actuator position. Detailed Implementation

[0025] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0026] This invention provides a method for detecting pupil plane rotation and drift in deformable secondary mirror telescopes. The working principle and process of this invention are as follows: During the open-loop pupil rotation and drift detection process, when a specific voltage is applied to the actuator at a specific position, the deformable secondary mirror at the corresponding position of the actuator will deform, forming a local aberration. The slope of the sub-aperture of the wavefront sensor corresponding to the position of the aberration will change. The slope of the wavefront sensor is collected, and the actual position of the specific actuator on the wavefront sensor can be calculated based on the direction and amplitude of the slope change. The pupil plane rotation angle and the pupil plane center position relative to the initial position are fitted by the current actual position of the specific actuator. In the closed-loop pupil rotation and drift detection process, the positional relationship of the deformable secondary mirror actuator on the wavefront sensor is implied in the actuator voltage and the wavefront sensor slope response. By continuously collecting deformable secondary mirror voltage and wavefront sensor slope data during the closed-loop process, and taking data for a specific time period, after eliminating system periodic delay and filtering out the influence of low-frequency atmospheric turbulence, a correlation analysis of the voltage slope can be performed to obtain the response relationship between the sub-aperture slope and the actuator voltage. The position of the actuator is determined by the sub-aperture distribution with the most obvious slope response for each actuator. Then, a robust algorithm is used to fit the position of the actuator with larger errors to obtain the pupil surface state in the closed-loop state, and the pupil rotation and drift values ​​are updated at a high frequency for closed-loop compensation. Because open-loop detection has high accuracy but cannot be performed at any time during the closed-loop process, it is suitable for observing stationary or slowly moving targets. Closed-loop detection has real-time performance but lower accuracy than open-loop detection, so it is suitable for observing fast-moving targets or targets that require continuous closed-loop observation and cannot be detected by open-loop detection. Based on the calculated pupil rotation angle and pupil center drift, the control matrix of the deformable secondary mirror can be updated to ensure that the control matrix always matches the current correspondence between the deformable secondary mirror and the wavefront sensor.

[0027] The following detailed description, in conjunction with the accompanying drawings, illustrates the specific implementation process as part of this specification. It demonstrates the principles of the invention through implementation, and other aspects, features, and advantages of the invention will become apparent from this detailed description.

[0028] Figure 1 A flowchart of the pupil plane rotation and drift detection method for a deformable secondary mirror telescope according to the present invention is shown, as follows: Figure 1 As shown, the method includes the following steps:

[0029] Step S110: When the telescope's adaptive optics system is in open loop, perform high-precision open-loop pupil rotation and pupil drift detection. First, apply a specific positive and negative voltage sequence to the pre-selected driver on the deformable secondary mirror, which has a specific spatial distribution (such as a hexagonal distribution) on the pupil. Then, acquire the slope output of the Shaker-Hartmann wavefront sensor, and calculate the corresponding position of the pre-selected driver on the wavefront sensor based on the slope. Finally, fit the pupil rotation angle and the pupil center position to obtain the result.

[0030] The acquisition time for the slope output of the Shaker-Hartmann wavefront sensor is much shorter than the time required for global response matrix measurement.

[0031] The process of fitting the pupil rotation angle and the pupil center position includes: performing a straight line fitting on the actuator located on the same straight line passing through the center of the deformable secondary mirror, calculating the angle between the straight line and the theoretical position to obtain the pupil rotation angle; performing a robust geometric fitting on the back-calculated actuator position, and calculating its center position based on the fitted geometry as the pupil center position.

[0032] Among them, the open-loop pupil rotation and pupil drift detection selects a specific number of actuators greater than or equal to 3, but less than the total number of actuators. The actuators are arranged in a specific regular spatial distribution and have rotational symmetry around the center position of the deformable secondary mirror.

[0033] In open-loop pupillary drift detection, for A pre-selected driver loads a specific sequence of positive and negative voltages, the voltage sequence The expression is:

[0034] ,

[0035] ,

[0036] in, These are the deformable secondary mirror driver number and voltage sequence number, respectively. for An orthogonal square matrix of order n, with dimensions n ,and Multiples of 4 For square array No. Line number The column takes values, and its meaning is the first value. The deformable secondary mirror driver The absolute value of the applied voltage, an integer. integer In each deformable secondary mirror driver When power is applied, positive and negative voltages are applied respectively. For the first The deformable secondary mirror driver The positive voltage value upon initial power-on For the first The deformable secondary mirror driver The negative voltage value upon initial power-on.

[0037] Select from the pre-selected drives The actuator group, whose theoretical position lies on a straight line passing through the center of the deformable secondary mirror, is fitted with a straight line using the actuator position calculated by inverse slope, based on... The pupil rotation angle is obtained by averaging the angles between the straight lines and the theoretical position, and is an integer. .

[0038] The center position of the pupil surface is obtained by fitting the driver position obtained by inverse calculation of the slope to a specific driver center position.

[0039] Step S120: When the telescope adaptive optics system is closed, online closed-loop pupil rotation and pupil drift detection is performed. First, the voltage of the deformable secondary mirror driver and the slope of the Shaker-Hartmann wavefront sensor are synchronously acquired at each moment in the closed-loop state. Then, the data is preprocessed according to the system conditions. Next, the correlation coefficient matrix between the preprocessed deformable secondary mirror driver voltage and the wavefront sensor slope is solved. Based on the correlation coefficient matrix, the position of the pre-selected driver on the wavefront sensor is calculated. Finally, the pupil rotation angle and the pupil center position are fitted to obtain the results.

[0040] Data preprocessing includes: time delay alignment / elimination of system time delay and high-pass filtering of driver voltage and sensor slope to suppress the influence of low-frequency components of atmospheric turbulence and closed-loop control, and extraction of signal components that reflect the inherent mapping relationship of the system.

[0041] The fitting process to obtain the pupil rotation angle and pupil center position includes: performing linear fitting on the actuator located on the same straight line passing through the center of the deformable secondary mirror, calculating the angle between the straight line and the theoretical position to obtain the pupil rotation angle, and calculating the intersection of multiple straight lines to obtain the pupil center position.

[0042] The expressions for the deformable secondary mirror driver voltage and wavefront sensor slope after eliminating system time delay are:

[0043] ,

[0044] ,

[0045] in, and After eliminating system latency The voltage of the deformable secondary mirror driver and the slope of the wavefront sensor at any given moment. Obtained directly The voltage of the deformable secondary mirror driver at any given time. Obtained directly Wavefront sensor slope at time, integer This represents the system delay cycle number.

[0046] High-pass filtering sets the cutoff frequency to be [value missing] for the deformable secondary mirror driver voltage and the wavefront sensor slope. High-pass filter, cutoff frequency It equals the error suppression bandwidth under the current system state.

[0047] The formula for calculating the correlation coefficient matrix between the voltage of the deformable secondary mirror driver and the slope of the wavefront sensor is as follows:

[0048] ,

[0049] ,

[0050] in, and These represent the slope number of the wavefront sensor and the driver number of the deformable secondary mirror, respectively. Let covariance matrix be the variance matrix. For the first The slope of the first wavefront sensor and the first The covariance of the voltage of the deformable secondary mirror driver The length of the collected data. for Time of the first Each wavefront sensor slope value, for Time of the first Voltage value of the deformable secondary mirror driver The correlation coefficient matrix, For the first The slope of the first wavefront sensor and the first The correlation coefficient of the voltage of the deformable secondary mirror driver and The first The slope of the first wavefront sensor and the first The standard deviation of the voltage of each deformable secondary mirror driver over this data length.

[0051] The location of the pre-selected actuator is calculated based on the correlation coefficient matrix. The selected actuator is far from the edge of the pupil surface, has a high slope response signal-to-noise ratio, and is arranged in a specific regular spatial distribution, with rotational symmetry around the center of the deformable secondary mirror.

[0052] Based on the back-calculated location of the manually selected driver, select The actuator group is theoretically located on a straight line passing through the center of the deformable secondary mirror. A straight line fit is performed on the actuator position based on... The pupil rotation angle is obtained by averaging the angles between the straight lines and the theoretical position. The center of the pupil plane is obtained by taking the center of the intersection of the three straight lines. (Integer) .

[0053] Step S130: Based on the telescope status and the changing status of the tracked target, first select the deformable secondary mirror control matrix calculated according to the theoretical pupil surface status or the previous measured matrix as the initial matrix. Then select open-loop pupil rotation and pupil drift detection or closed-loop pupil rotation and pupil drift detection, update the deformable secondary mirror control matrix according to the measured pupil surface status, and correct the error in the initial matrix.

[0054] When the target's movement speed is slow, the system performs high-precision open-loop pupil rotation and drift detection before closing the loop, and then updates the deformable secondary mirror control matrix based on the pupil rotation and drift status to achieve closed-loop control. When the target's movement speed is fast, the system obtains an initial deformable secondary mirror control matrix through theoretical calculation or open-loop detection before closing the loop, and then performs closed-loop online pupil rotation and drift detection, updates the pupil rotation and drift status in real time, updates the control matrix, and corrects errors in the initial matrix.

[0055] In specific implementation of this invention, such as Figure 2 As shown, the deformable secondary mirror contains 241 actuators (as indicated by reference numeral 2 in the attached figure), and the Shaker-Hartmann wavefront sensor contains 60 sub-apertures (as indicated by reference numeral 1 in the attached figure). During open-loop pupil plane rotation and drift detection, based on its theoretical design, six hexagonal actuators are selected as the energized actuators, i.e., the actuators excited in the open-loop detection method (as indicated by reference numeral 3 in the attached figure). These six actuators are not located in the outermost or innermost aperture rings on the wavefront sensor, and their slope response has a large signal-to-noise ratio, making them suitable for high-precision open-loop detection. The six actuators are then loaded as follows... Figure 3 The Hadamard positive and negative voltage sequence is shown. The Hadamard matrix has an order of 8. The voltage is applied 16 times. The slope output is calculated and averaged from 20 frames of images acquired by the Shaker-Hartmann wavefront sensor after the voltage is applied. This average is used as the slope output of the wavefront sensor.

[0056] Based on the slope of the wavefront sensor, the actual actuator positions of the six actuators at the wavefront sensor are calculated, such as... Figure 4 As shown. For the six drivers located at the six vertices of the regular hexagon, solve for the lines by pairwise solving for each diagonal, and then... Figure 2 The angle between each pair of diagonal lines is calculated, and the average of the three angles is taken to obtain the pupil rotation angle. Using the random sampling consensus method, four solved actuator positions are randomly selected for hexagonal fitting, and the optimal model is repeatedly iterated to find the optimal model. The center position of the hexagon is calculated, and the center position of the pupil is obtained as 5.

[0057] During closed-loop pupil rotation and drift detection, a preliminary closed loop is first achieved based on the control matrix calculated from the open-loop pupil rotation and drift detection. During the closed-loop process, the voltage of the deformable secondary mirror driver and the slope data of the wavefront sensor are continuously acquired for 5 seconds at a sampling frequency of 100Hz. The system time delay is set to 2 sampling cycles under the closed-loop frame frequency of 100Hz, and the cutoff frequency of the high-pass filter matched with the error suppression bandwidth is 10Hz. After data processing, the correlation coefficient matrix between the voltage of the deformable secondary mirror driver and the sub-aperture slope can be obtained, with a dimension of 241×120.

[0058] Based on the correlation coefficient matrix, all effective driver positions can be calculated, such as... Figure 5 As shown. Since the outer and inner ring actuators are located outside the detection range of the wavefront detector's sub-aperture, the number of effective actuators that can be calculated is less than the total number of actuators. To simplify the calculation and remove the influence of edge actuators with large errors on the fitting results, Figure 2 Using the six actuators forming the vertices of a regular hexagon as a reference, two more actuators are taken from each diagonal towards the center, for a total of 18 actuators, which are then selected manually. Figure 5 As shown. Using these 18 actuators, actuator position 4 is obtained. Then, principal component analysis is used to fit three sets of six actuators passing through the diagonal of the vertices of the regular hexagon, resulting in three fitted lines. The angles between the three lines and the theoretical line are calculated, and the average is taken to obtain the pupil rotation angle. The positions of the three intersection points of the three lines are calculated, and the center is taken to obtain the pupil center position 5.

[0059] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of explaining or limiting the subject matter of the invention.

Claims

1. A method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope, characterized in that, Includes the following steps: Step S110: When the telescope adaptive optics system is open-loop, perform high-precision open-loop pupil rotation and pupil drift detection. First, apply a specific positive and negative voltage sequence to the pre-selected drivers on the deformable secondary mirror that are spatially distributed on the pupil. Then, collect the slope output of the Shaker-Hartmann wavefront sensor. Then, calculate the position of the pre-selected driver on the wavefront sensor based on the slope. Finally, fit the pupil rotation angle and the pupil center position. Step S120: When the telescope adaptive optics system is closed, perform online closed-loop pupil rotation and pupil drift detection. First, synchronously collect the voltage of the deformable secondary mirror driver and the slope of the Shaker-Hartmann wavefront sensor at each moment in the closed-loop state. Then, preprocess the data according to the system conditions, and solve the correlation coefficient matrix between the preprocessed deformable secondary mirror driver voltage and the wavefront sensor slope. Based on the correlation coefficient matrix, calculate the position of the pre-selected driver on the wavefront sensor. Finally, fit the pupil rotation angle and the pupil center position. Step S130: Based on the telescope status and the changing status of the tracked target, first select the deformable secondary mirror control matrix calculated according to the theoretical pupil surface status or the previous measured matrix as the initial matrix. Then select open-loop pupil rotation and pupil drift detection or closed-loop pupil rotation and pupil drift detection, update the deformable secondary mirror control matrix according to the measured pupil surface status, and correct the error in the initial matrix.

2. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S110, the number of pre-selected drivers is greater than or equal to 3, but less than the total number of drivers. The drivers are arranged in a specific regular spatial distribution and have rotational symmetry around the center position of the deformable secondary mirror.

3. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S110, for A pre-selected driver loads a specific positive and negative voltage sequence, the voltage sequence The expression is: ， ， in, These are the deformable secondary mirror driver number and voltage sequence number, respectively. for An orthogonal square matrix of order n, with dimensions n ,and Multiples of 4 For square array No. Line number The column takes values, and its meaning is the first value. The deformable secondary mirror driver The absolute value of the applied voltage, an integer. integer In each deformable secondary mirror driver When power is applied, positive and negative voltages are applied respectively. For the first The deformable secondary mirror driver The positive voltage value upon initial power-on For the first The deformable secondary mirror driver The negative voltage value upon initial power-on.

4. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S110, a driver is selected from the pre-selected drivers. The actuator group, whose theoretical position lies on a straight line passing through the center of the deformable secondary mirror, is fitted with a straight line using the actuator position calculated by inverse slope, based on... The pupil rotation angle is obtained by averaging the angles between the straight lines and the theoretical position, and is an integer. .

5. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S110, the driver position obtained by inverse calculation of the slope is fitted to the pre-selected driver center position to obtain the pupil center position.

6. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S120, the data preprocessing includes two steps: eliminating system time delay and high-pass filtering.

7. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 6, characterized in that, The expressions for the deformable secondary mirror driver voltage and wavefront sensor slope after eliminating the system time delay are as follows: ， ， in, and After eliminating system latency The voltage of the deformable secondary mirror driver and the slope of the wavefront sensor at any given moment. Obtained directly The voltage of the deformable secondary mirror driver at any given time. Obtained directly Wavefront sensor slope at time, integer This represents the system delay cycle number.

8. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 6, characterized in that, The high-pass filter sets the cutoff frequency to be [value missing] for the deformable secondary mirror driver voltage and the wavefront sensor slope. High-pass filter, cutoff frequency It equals the error suppression bandwidth under the current system state.

9. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 7, characterized in that, In step S120, the formula for calculating the correlation coefficient matrix between the deformable secondary mirror driver voltage and the wavefront sensor slope is as follows: ， ， in, and These represent the slope number of the wavefront sensor and the driver number of the deformable secondary mirror, respectively. Let covariance matrix be the variance matrix. For the first The slope of the first wavefront sensor and the first The covariance of the voltage of the deformable secondary mirror driver The length of the collected data. for Time of the first Each wavefront sensor slope value, for Time of the first Voltage value of the deformable secondary mirror driver The correlation coefficient matrix, For the first The slope of the first wavefront sensor and the first The correlation coefficient of the voltage of the deformable secondary mirror driver and The first The slope of the first wavefront sensor and the first The standard deviation of the voltage of the deformable secondary mirror driver over this data length.

10. The method for detecting pupil plane rotation and drift in a deformable secondary mirror telescope according to claim 1, characterized in that, In step S120, the pre-selected driver position is selected based on the back-calculated position. The actuator group is theoretically located on a straight line passing through the center of the deformable secondary mirror. A straight line fit is performed on the actuator position based on... The pupil rotation angle is obtained by averaging the angles between the straight lines and the theoretical position. The center of the pupil plane is obtained by taking the center of the intersection of the three straight lines. (Integer) .

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