Dynamic star point positioning method, device and equipment based on effective line spread function

Abstract

This application provides a dynamic star point localization method, apparatus, and device based on an effective line spread function, relating to the field of optical imaging measurement technology. The method includes: estimating the trailing parameters of a star point image based on the coarsely estimated coordinate position changes of the star point image on adjacent frames of starscape images; the coarsely estimated coordinate position characterizing the center position coordinates of the star point image obtained by calculating the centroid of the star point image using the threshold centroid method; establishing an effective line spread function under the current motion conditions based on an effective point spread function pre-established under static imaging conditions, and combining the trailing parameters; the effective line spread function characterizing the energy distribution pattern of the trailing star point image obtained by integrating the effective point spread function along the trailing trajectory; and using the effective line spread function to perform localization calculations on the imaging data of the trailing star point image to obtain a finely estimated coordinate of the star point image.

Description

Technical Field

[0001] This application relates to the field of optical imaging measurement technology, specifically to a dynamic star point positioning method, apparatus, and device based on the effective line spread function. Background Technology

[0002] Star sensors are the core components of spacecraft attitude determination systems. They enable high-precision autonomous astronomical attitude determination through star observation and are a key technological foundation for ensuring the successful implementation of space missions such as deep space exploration and high-resolution Earth observation.

[0003] When the star sensor is in dynamic operation, the relative motion between the star target and the imaging system causes the star spot to shift on the image plane during exposure. Light energy accumulates on multiple pixels along the spot's trajectory, forming a trailing image. This phenomenon causes energy dispersion and a reduced signal-to-noise ratio, directly affecting the accuracy of star positioning. Furthermore, the energy distribution pattern of the trailing image differs significantly from that under static imaging conditions, rendering the effective point spread function model of the star sensor based on static imaging assumptions inapplicable. This limits high-precision spot positioning and attitude measurement under dynamic conditions.

[0004] To address the problem of star sensor measurement under dynamic conditions, related technologies mainly follow two routes: one is to improve the signal-to-noise ratio and star extraction success rate of dynamic star images through image enhancement and filtering; the other is to restore long trailing speckles to circular speckles through image restoration. However, existing studies generally adopt image post-processing methods, focusing on enhancing or repairing the image after the star trailing occurs. While filtering and restoration processes improve the signal-to-noise ratio, they may also alter the true energy distribution of the stars, introducing new errors that are difficult to quantify.

[0005] Therefore, how to achieve high-precision positioning of star spots under dynamic imaging conditions is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this application is to provide a dynamic star point positioning method, apparatus, and device based on an effective line spread function. This can solve the problems in related technologies where positioning accuracy is limited due to star point image trailing and the inapplicability of the effective point spread function model based on static assumptions under dynamic conditions. By fusing the static effective point spread function with image motion information to construct an effective line spread function, high-precision positioning of dynamic star point images can be achieved, providing a reliable technical approach to improve the attitude measurement accuracy of star sensors under dynamic imaging conditions.

[0007] To solve the above-mentioned technical problems, this application is implemented as follows: A first aspect of this application discloses a dynamic star point positioning method based on an effective line spread function, the method comprising: Based on the coarsely estimated coordinate position change of star spots in adjacent frames of star sky images, the trailing parameter of star spots is estimated. The coarsely estimated coordinate position represents the center position coordinates of star spots calculated by the threshold centroid method. Based on the effective point spread function established in advance under static imaging conditions, and combined with the trailing parameters, an effective line spread function under the current motion conditions is established. The effective line spread function is used to characterize the energy distribution pattern of the trailing star spot obtained by integrating the effective point spread function along the trailing trajectory. Using the effective line spread function, the imaging data of the star spot forming a trailing pattern is used to perform positioning calculations to obtain the fine estimated coordinates of the star spot.

[0008] Optionally, the trailing parameters include trailing length and trailing direction; the trailing parameters of the star spots are estimated based on the coarsely estimated coordinate position changes of the star spots in adjacent frames of starry sky images, including: A star sensor image plane coordinate system is constructed with the lower left corner vertex of the star sensor image plane as the origin, the horizontal direction of the image plane as the positive X-axis, and the vertical direction of the image plane as the positive Y-axis; the coordinate values ​​in the star sensor image plane coordinate system represent the position of the star spot in the pixel array. Using the star sensor image plane coordinate system as a position reference, star map recognition is performed on the star sky image, and the center position coordinates of the star point image spots corresponding to the same navigation star in the current frame star sky image and the previous frame star sky image are calculated using the threshold centroid method. The velocity vector of star spots on the image plane is calculated based on the sampling time interval between adjacent frames, the center position coordinates of the current frame star image, and the center position coordinates of the previous frame star image. The trail length is calculated based on the magnitude of the motion velocity vector and the exposure time of the star sensor; The trailing direction is determined based on the direction of the motion velocity vector; wherein, the trailing direction is the angle between the motion velocity vector and the positive X-axis direction.

[0009] Optionally, based on the effective point spread function pre-established under static imaging conditions, and incorporating the trailing parameters, an effective line spread function under the current motion conditions is established, including: Under static imaging conditions, multi-frame average imaging data of point target spots at different sub-pixel positions on the image plane are acquired, the effective point spread function discrete sampling matrix of the star sensor is established, and the effective point spread function is obtained by interpolating the effective point spread function discrete sampling matrix through a two-dimensional interpolation method. The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction; wherein, the number of discrete points is positively correlated with the trailing length. Based on the sub-pixel coordinates, the arithmetic mean of the effective point spread function at each discrete point on the trailing trajectory is calculated, which is used as the effective line spread function under the current motion conditions.

[0010] Optionally, the trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction, including: Using the midpoint of the trailing trajectory as a reference point, the trailing trajectory is divided into multiple discrete points at equal intervals along the trailing direction, and the position offset of each discrete point relative to the reference point is determined. The sub-pixel coordinates of each discrete point relative to the target pixel center are calculated based on the offset of the star spot center relative to the pixel center, the position offset, and the trailing direction.

[0011] Optionally, the effective line spread function is used to perform localization calculations on the imaging data of the star-shaped image spots that form a trailing pattern, obtaining a fine estimate of the coordinates of the star-shaped image spots, including: Based on the effective line spread function, a joint probability density function of the pixel matrix within the region of interest in star spot imaging with respect to the center position of the star spot is constructed; The maximum likelihood estimation method is used to obtain the center position of the star spot that maximizes the probability of the pixel matrix by iteratively optimizing and minimizing the cost function derived from the joint probability density function. This position is then used as the fine-estimated coordinate of the star spot.

[0012] Optionally, the maximum likelihood estimation method is used to obtain the center position of the star spot that maximizes the probability of the pixel matrix by iteratively optimizing and minimizing the cost function derived from the joint probability density function, including: Taking the negative natural logarithm of the joint probability density function, a cost function is constructed regarding the center position of the star spot. Using the coarsely estimated coordinate position as the initial value for iteration, set the threshold for the number of iterations and the threshold for the iterative change of the star spot position coordinates; The cost function is iteratively optimized using the Newton-Raphson method, and the coordinates of the center position of the star spot are updated in each iteration. If the change in the coordinates of the center position of the star spot is less than the iteration change threshold during the iteration process, or if the number of iterations reaches the iteration number threshold, then the iteration is terminated. The coordinates of the star spot center obtained at the end of the iteration are taken as the star spot center position that maximizes the probability of the pixel matrix appearing.

[0013] Optionally, the method further includes: During the measurement process, if the positioning accuracy of the effective line spread function does not meet the preset measurement requirements, the trailing parameters of the star spot are re-estimated and the effective line spread function is updated for positioning calculation.

[0014] Optionally, the preset measurement requirements include: when the change in the field of view angle of the star sensor corresponding to the range of motion of the star spot on the image plane exceeds a preset angle threshold, it is determined that the positioning accuracy does not meet the requirements.

[0015] A second aspect of this application discloses a dynamic star point positioning device based on an effective line spread function, the device comprising: The parameter estimation module is used to estimate the trailing parameters of star spots based on the coarsely estimated coordinate position changes of star spots in adjacent frames of star sky images. The coarsely estimated coordinate position represents the center position coordinates of the star spots calculated by the threshold centroid method. The function establishment module is used to establish an effective line spread function under the current motion conditions based on the effective point spread function established in advance under static imaging conditions and the tail parameters. The effective line spread function is used to characterize the energy distribution pattern of the trailing star spot obtained by integrating the effective point spread function along the trailing trajectory. The positioning calculation module is used to perform positioning calculations on the imaging data of the star spot that forms a trailing pattern using the effective line spread function, so as to obtain the fine estimated coordinates of the star spot.

[0016] A third aspect of this application discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the dynamic star point positioning method based on the effective line spread function described in the first aspect of this application.

[0017] A fourth aspect of this application discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the dynamic star point positioning method based on the effective line spread function described in the first aspect of this application.

[0018] A fifth aspect of this application discloses a computer program product, including a computer program that, when executed by a processor, implements the steps of the dynamic star point positioning method based on the effective line spread function described in the first aspect of this application.

[0019] The embodiments of this application have the following advantages: First, the trailing parameters of star spots are estimated by coarsely estimating the coordinate position changes of star spots in adjacent frames, enabling real-time perception of the spot motion state. Then, based on a pre-calibrated static effective point spread function, the effective point spread function is integrated along the trailing trajectory by combining the trailing parameters to construct the effective line spread function under the current motion conditions. This process, starting from the imaging physical model, fuses imaging characteristics under static conditions with dynamic motion information, ensuring that the established effective line spread function accurately describes the true energy distribution of the trailing spots, thus overcoming the defect in related technologies where the static imaging model fails due to neglecting motion information.

[0020] Secondly, the established effective line spread function is used to directly calculate the location of the trailing speckle in the imaging data, eliminating the need for post-processing steps such as image enhancement, filtering, or restoration. Compared to related techniques that use post-processing to repair trailing images, which may alter the true energy distribution of stars and introduce errors that are difficult to quantify, this method, based on forward modeling of the imaging physics model, performs location calculations from the data source, enabling a more accurate reconstruction of the star center position.

[0021] Furthermore, through a linkage mechanism between trailing parameter estimation and the effective line spread function, the method can adapt to dynamic imaging conditions with different motion speeds and trailing lengths. When the image speckle motion state changes, the trailing parameters are updated accordingly, and the effective line spread function is adjusted accordingly, always maintaining the best match for the current imaging conditions and exhibiting good dynamic adaptability.

[0022] In summary, this application, starting from imaging physics modeling, integrates motion information to construct an effective line spread function, achieving high-precision positioning of dynamic star points, and providing a reliable technical approach to improve the measurement accuracy of optical imaging measurement systems such as star sensors under dynamic conditions. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating the steps of a dynamic star point positioning method based on an effective line spread function provided in an embodiment of this application. Figure 2 This is a schematic diagram of the velocity vector estimation of an image spot on the image plane provided in an embodiment of this application; Figure 3This is a schematic diagram of the target imaging energy distribution of a star sensor under static and dynamic conditions, provided in an embodiment of this application. Figure 4 This is a flowchart of another dynamic star point positioning method based on the effective line spread function provided in this application embodiment; Figure 5 This is a schematic diagram of the structure of a dynamic star point positioning device based on an effective line diffusion function provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] This application provides a dynamic star point localization method, apparatus, and device based on an effective line spread function. The technical concept addresses the problem of decreased localization accuracy caused by star spot trailing due to motion in dynamic imaging conditions. Starting from the imaging physics model, a pre-calibrated static effective point spread function is fused with spot motion information to construct an effective line spread function that accurately describes the energy distribution pattern of the trailing spot. Specifically, firstly, the trailing parameters are estimated using the coarsely estimated coordinate changes of star spots in adjacent frames, achieving real-time perception of the motion state. Then, based on the static effective point spread function, an effective line spread function under the current motion conditions is established by integrating along the trailing trajectory. Finally, based on this function, the maximum likelihood estimation method is used to calculate the localization of the trailing spot, obtaining precise center coordinates of the star spot. This method avoids the additional errors that may be introduced by traditional image post-processing, achieving high-precision localization of dynamic star points from the data source and possessing good dynamic adaptability.

[0027] The dynamic star point positioning method, apparatus, and device based on the effective line spread function provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0028] Reference Figure 1 As shown, Figure 1 This is a flowchart illustrating the steps of a dynamic star point localization method based on an effective line spread function, as provided in an embodiment of this application. Figure 1 As shown, the method may include steps S110 to S150: Step S110: Estimate the trailing parameters of the star spot based on the coarsely estimated coordinate position change of the star spot on the adjacent frame star sky image. The coarsely estimated coordinate position represents the center position coordinates of the star spot calculated by the threshold centroid method.

[0029] Among them, star spots refer to the image spots formed by stellar targets on the star sensor image sensor. The coarsely estimated coordinate position is calculated using the threshold centroid method, with an accuracy typically at the sub-pixel level, and is mainly used to obtain the motion trend of the image spots. The trailing parameters include the trailing length and trailing direction, which are used to describe the motion state of the image spots during exposure.

[0030] Specifically, under dynamic imaging conditions, star sensors produce a trailing effect due to the relative motion of star spots, and the shape of the trailing effect is determined by the velocity vector. To obtain the current motion state, this step first performs star pattern recognition on two adjacent frames of starscape images and uses the threshold centroid method to roughly calculate the center coordinates of the star spots of the same navigation star on the image plane. The threshold centroid method has low computational cost and high speed, which can meet real-time requirements, but its positioning accuracy is limited, hence it is called "coarse estimation of coordinate position". By comparing the changes in the coarsely estimated coordinate positions of adjacent frames and combining them with the known inter-frame sampling time interval, the velocity vector of the star spots on the image plane can be estimated, and then the trailing parameters such as the trailing length and trailing direction can be calculated.

[0031] Step S120: Based on the effective point spread function established in advance under static imaging conditions, and by combining the trailing parameters, an effective line spread function is established under the current motion conditions. The effective line spread function is used to characterize the energy distribution pattern of the trailing star point image spots obtained by integrating the effective point spread function along the trailing trajectory.

[0032] Under static imaging conditions, the imaging characteristics of a star sensor can be accurately described by the effective point spread function (PSF). This function integrates factors such as optical system diffraction, aberrations, and sensor response, and is the essential imaging model of the system. In this step, based on the pre-calibrated static effective point spread function and combined with the trailing parameters estimated in step S110, the static effective point spread function is integrated or accumulated along the trailing trajectory to construct an effective line spread function (LSF) suitable for the current motion conditions. This function reflects the cumulative energy distribution pattern of the star spot along the motion trajectory on the image plane during the exposure time, thus extending the static imaging model to dynamic imaging scenarios.

[0033] Step S130: Using the effective line spread function, perform localization calculations on the imaging data of the star spot that forms a trailing pattern to obtain the fine estimated coordinates of the star spot.

[0034] After obtaining the effective line spread function under the current motion conditions, this step utilizes this function to perform high-precision localization of the trailing star-shaped image patch. Specifically, based on the effective line spread function, a joint probability density function of the pixel matrix within the region of interest with respect to the center position of the star-shaped image patch is constructed. The center position coordinates that maximize this probability density function are then iteratively solved using the maximum likelihood estimation method. Since the effective line spread function accurately describes the energy distribution pattern of the trailing image patch, the localization calculation based on this model can fully utilize the response value information of each pixel, achieving theoretically optimal localization accuracy under noisy conditions. The final obtained center position coordinates of the star-shaped image patch are the fine-estimated coordinates, which have a higher accuracy than the coarse-estimated coordinates in step S110.

[0035] The technical solution adopted in this embodiment estimates the trailing parameters based on coarse coordinate estimation from adjacent frames, enabling real-time perception of the image spot's motion state. Then, by combining the static effective point spread function and the trailing parameters, an effective line spread function under the current motion conditions is constructed to accurately describe the energy distribution pattern of the trailing image spot. Finally, maximum likelihood estimation is performed based on this function to obtain the finely estimated coordinates of the star point image spot. This method, starting from the imaging physical model, fuses static system characteristics with dynamic motion information, avoiding the additional errors that may be introduced by traditional image post-processing, achieving high-precision positioning of dynamic star points, and possessing good dynamic adaptability.

[0036] In an optional embodiment, the trailing parameters include trailing length and trailing direction. Step S110 above, "estimating the trailing parameters of the star spots based on the coarsely estimated coordinate position changes of the star spots on adjacent frame starscape images," may include the following steps S110-1 to S110-5: Step S110-1: Construct a star sensor image plane coordinate system with the lower left corner vertex of the star sensor image plane as the origin, the horizontal direction of the image plane as the positive X-axis, and the vertical direction of the image plane as the positive Y-axis; the coordinate values ​​in the star sensor image plane coordinate system represent the position of the star spot in the pixel array.

[0037] To facilitate the description of the spatial location of star spots, a coordinate system for the star sensor image plane is established. The origin O is set at the lower left corner of the image sensor image plane. The positive X-axis extends horizontally (to the right along the row direction of the pixel array), and the positive Y-axis extends vertically (upward along the column direction of the pixel array), forming a two-dimensional Cartesian coordinate system. Within this coordinate system, any coordinate value... It directly corresponds to the actual position of the star-shaped image spots in the pixel array.

[0038] Step S110-2: Using the star sensor image plane coordinate system as a position reference, perform star map recognition on the star sky image, and use the threshold centroid method to calculate the center position coordinates of the star point image spots corresponding to the same navigation star in the current frame star sky image and the previous frame star sky image.

[0039] Star image recognition is performed on the star-sensor-acquired sky images to determine the star spots corresponding to the same navigation star in the current frame and the previous frame. For the same identified navigation star, a region of interest is delineated in its respective frame, and the center position coordinates of the star spot are calculated using the threshold centroid method. Let the calculated center position coordinates of the current frame and the previous frame be respectively... and .

[0040] Step S110-3: Calculate the velocity vector of star spots on the image plane based on the sampling time interval between adjacent frames, the center position coordinates of the current frame star image, and the center position coordinates of the previous frame star image.

[0041] The motion of the star spot on the image plane is caused by the relative angular motion between the star sensor and the star. In the short term, it can be approximated that the spot moves at a uniform linear velocity. Let the sampling times of the current frame and the previous frame be... and Then the time interval between adjacent frames is The components of the velocity vector in the X and Y axes are determined by the ratio of the coordinate change to the time interval, i.e., the velocity component in the X-axis direction. and the velocity component in the Y-axis direction They can be represented as follows:

[0042]

[0043] This yields the velocity vector of the star-shaped image spots on the image plane. This vector reflects the direction and rate of motion of the star-shaped image during exposure. Figure 2 This is a schematic diagram of the velocity vector estimation of an image spot on the image plane provided in an embodiment of this application.

[0044] Step S110-4: Calculate the trail length based on the magnitude of the motion velocity vector and the exposure time of the star sensor.

[0045] Wherein, the magnitude of the velocity vector It is obtained by taking the square root of the sum of the squares of the two components, that is:

[0046] The trailing length refers to the displacement distance of the image spot along the direction of motion during the exposure time, and is equal to the product of the magnitude of the velocity vector and the exposure time. Let the exposure time of the star sensor be... Then the length of the trail It can be represented as:

[0047] Understandably, the trail length is measured in pixels and reflects the length of the trailing image in the direction of motion.

[0048] Step S110-5: Determine the trailing direction based on the direction of the motion velocity vector; wherein the trailing direction is the angle between the motion velocity vector and the positive X-axis direction.

[0049] Specifically, the trailing direction is determined by the direction of the velocity vector, that is, the direction of the image spot's trajectory during exposure. Trailing direction angle. Defined as the angle between the velocity vector and the positive X-axis direction of the image plane, its calculation formula is:

[0050] The technical solution of this embodiment establishes a spatial coordinate system and quickly obtains coarsely estimated coordinates using the threshold centroid method. The motion velocity vector is calculated based on the coordinate changes between adjacent frames, reflecting the motion state of the image spot. Further calculations yield the trailing length and direction, which together constitute a complete description of the trailing image spot morphology. This achieves accurate estimation of the trailing parameters of star-shaped image spots under dynamic imaging conditions, providing accurate motion information input for the subsequent construction of the effective line spread function.

[0051] In an optional embodiment, step S120 above, "based on the effective point spread function pre-established under static imaging conditions, and combining the trailing parameters, to establish the effective line spread function under the current motion conditions," may include the following steps S120-1 to S120-3: Step S120-1: Under static imaging conditions, acquire multi-frame average imaging data of point target spots at different sub-pixel positions on the image plane, establish the effective point spread function discrete sampling matrix of the star sensor, and interpolate the effective point spread function discrete sampling matrix using a two-dimensional interpolation method to obtain the effective point spread function.

[0052] The effective point spread function is the core model describing the star sensor's response to a point light source imaging. To obtain this function, a calibration experiment was conducted under static imaging conditions: a point light source was used to simulate an infinitely distant star target via a collimator, and the star sensor was fixed on a high-precision turntable. By controlling the turntable to perform a two-axis step rotation with a small angle, the star spot produced a fine sub-pixel displacement on the image plane.

[0053] After stabilization at each sub-pixel location, multiple frames (e.g., 30 frames) of images are acquired and averaged to suppress random noise. By traversing all sub-pixel locations, the sampled values ​​of the effective point spread function on the discrete grid are obtained, forming a discrete sampling matrix. Two-dimensional interpolation techniques (such as cubic spline interpolation or bilinear interpolation) are used to interpolate the discrete sampling matrix to recover the effective point spread function of the continuous distribution. Under static imaging conditions, the center of the image spot relative to the pixel... The central location is At that time, the response value of the pixel after removing the background value and dark signal is .

[0054] Step S120-2: The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction; wherein, the number of discrete points is positively correlated with the trailing length.

[0055] The trailing trajectory is determined by the trailing length. and trailing direction It was jointly determined that it can be regarded as a line with the center of the star-shaped image spot as the midpoint and a length of [missing information]. , direction is The line segment. To numerically construct the effective line spread function, the trajectory is discretized into a finite number of points, and the cumulative effect of the entire trajectory is approximated by the effective point spread function values ​​at these points. The number of discrete points N and the tail length are... There is a positive correlation; for example, the value of N can be taken as... That is, the longer the tail, the more discrete points there are, in order to ensure the accuracy of the integral approximation.

[0056] This step is further implemented through the following sub-steps S120-2-1 to S120-2-2: Step S120-2-1: Using the midpoint of the trailing trajectory as a reference point, divide the trailing trajectory into multiple discrete points at equal intervals along the trailing direction, and determine the position offset of each discrete point relative to the reference point. Specifically, the trajectory is divided into N discrete points at equal intervals along the trailing direction, and the position offset of each discrete point relative to the reference point along the trajectory direction is: It can be represented as:

[0057] when hour, , corresponding to the starting point of the trail; when hour, , corresponding to the end of the trail.

[0058] Step S120-2-2: Calculate the sub-pixel coordinates of each discrete point relative to the target pixel center based on the offset of the star spot center relative to the pixel center, the position offset, and the trailing direction.

[0059] Specifically, let the center of the star-shaped image spot be relative to the target pixel. The sub-pixel offset at the center is The trailing angle is For each discrete point, its sub-pixel coordinates relative to the center of the target pixel. It equals the sub-pixel offset plus the position offset of the discrete point along the trailing direction, that is:

[0060] Step S120-3: Based on the sub-pixel coordinates, calculate the arithmetic mean of the effective point spread functions at each discrete point on the trailing trajectory, and use it as the effective line spread function under the current motion conditions.

[0061] For target pixel When the offset of the center of the star-shaped image spot relative to the center of the pixel is At that time, the response value of the pixel under dynamic imaging conditions can be determined by the effective line spread function. The description is obtained by taking the arithmetic mean of the effective point spread function values ​​at all discrete points on the trailing trajectory, that is:

[0062] This arithmetic averaging process is essentially a numerical approximation of the integral of the effective point spread function along the trailing trajectory, reflecting the energy distribution pattern formed by the accumulation of light energy along the motion trajectory during the exposure time. Figure 3 This is a schematic diagram of the target imaging energy distribution of a star sensor under static and dynamic conditions, provided in an embodiment of this application. From... Figure 3 From (a), we can see that under static conditions, the position of the star target remains unchanged, and the energy is concentrated at the center of the image spot (wherein...). (The location of the image spot center on the X-axis) is near; from Figure 3 As shown in (b), under dynamic conditions, the star target relative to the star sensor during the exposure time... The angular velocity motion of the image spot causes the center position of the image spot to change along the trajectory of motion, where , , , and These represent the points in time. , , , and The position of the image spot center on the X-axis is shown in the figure. The exposure time for the star sensor.

[0063] The technical solution of this embodiment realizes the construction from a static effective point spread function to a dynamic effective line spread function. A high-precision continuous static imaging model is established through sub-pixel displacement scanning and two-dimensional interpolation. The trailing trajectory is uniformly discretized, and the sub-pixel coordinates of each discrete point are accurately calculated, providing discrete sampling points for energy accumulation calculation. The energy accumulation on the trailing trajectory is calculated by arithmetic averaging, constructing an effective line spread function that accurately describes the energy distribution of the dynamic trailing image. This construction method starts from the imaging physical model, fusing the essential characteristics of the static system with dynamic motion information, enabling the established model to accurately characterize the true energy distribution morphology of the trailing image spot.

[0064] In an optional embodiment, step S130 above, "using the effective line spread function to perform localization calculations on the imaging data of the star spot forming the trailing pattern, and obtaining a fine estimate of the coordinates of the star spot," may include the following steps S130-1 to S130-2: Step S130-1: Based on the effective line spread function, construct the joint probability density function of the pixel matrix within the region of interest in star spot imaging with respect to the center position of the star spot.

[0065] The joint probability density function quantifies the different center locations. The probability of observing the current pixel matrix. Let the region of interest (ROI) for star spot imaging include... Each pixel in the region forms a pixel value matrix. During the imaging process, the pixels... The observed values ​​are affected by star energy, background radiation, and noise. According to the imaging physics model, the pixel... The expected number of photoelectrons in a target image is equal to the effective line spread function at that pixel divided by the gain coefficient K, plus the mean number of photoelectrons in the dark noise. Actual observations follow a Poisson distribution around this expected value. Therefore, at the center of a given star spot... Under the given conditions, the joint probability density function of the observed entire pixel matrix P is:

[0066] in, Indicates the center of the star point relative to the pixel. The sub-pixel offset at the center, where P is the pixel value matrix within the ROI. For pixels The pixel value, K is the gain coefficient of the star sensor image sensor from the number of photoelectrons to the pixel value. Let K be the variance of the pixel's dark signal level (dark noise variance), and s be the pixel value of the ambient background. Specifically, the gain coefficient K and the dark noise variance... It can be obtained by photon transfer method or by consulting a manual. s can be obtained by the average response value of pixels around the image spot without target energy distribution.

[0067] Step S130-2: Using the maximum likelihood estimation method, the cost function derived from the joint probability density function is minimized through iterative optimization to obtain the center position of the star spot that maximizes the probability of the pixel matrix appearing, which is then used as the fine estimated coordinate of the star spot.

[0068] Specifically, the basic idea of ​​maximum likelihood estimation is to find the parameter value that maximizes the probability of the observed data occurring, that is, to find the parameter value that maximizes the probability of the observed data occurring. The largest star point center position For ease of computation, maximization problems are usually transformed into minimization problems and solved through iterative optimization.

[0069] This step can be further achieved through the following steps S130-2-1 to S130-2-5: Step S130-2-1: Take the negative natural logarithm of the joint probability density function to construct a cost function for the center position of the star spot.

[0070] For example, the cost function It can be represented as:

[0071] It is understandable that maximizing the joint probability density function is equivalent to minimizing the cost function.

[0072] Step S130-2-2: Using the coarsely estimated coordinate position as the initial value for iteration, set the threshold for the number of iterations and the threshold for the iterative change of the star spot position coordinates.

[0073] Specifically, the coarsely estimated coordinate position obtained by the threshold centroid method in step S110 is used as the initial value for iteration. The initial value is close to the true center position, ensuring rapid convergence of the iteration. Two termination conditions are set: an iteration count threshold (e.g., 5 iterations) and an iteration change threshold for the image spot's position coordinates (e.g., 0.002 pixels). The iteration terminates when the position change is less than the iteration change threshold or the iteration count reaches the iteration count threshold.

[0074] Step S130-2-3: The cost function is iteratively optimized using the Newton-Raphson method, and the coordinates of the center position of the star spot are updated in each iteration.

[0075] Specifically, the Newton-Raphson method calculates the first and second derivatives of the cost function with respect to the position coordinates to obtain the update direction of the current position, gradually approximating the optimal solution. In each iteration, the expected response value of each pixel is recalculated using the currently estimated star center position, thereby updating the gradient and Hessian matrix to obtain a new position estimate.

[0076] Step S130-2-4: If the change in the coordinates of the center position of the star spot is less than the iteration change threshold during the iteration process, or the number of iterations reaches the iteration number threshold, then the iteration is terminated.

[0077] After each iteration, the change between the current estimated position and the previous estimated position is calculated. When the change is less than a preset iteration change threshold, it indicates that the position has stabilized, and further iteration offers limited improvement in accuracy; at this point, the iteration is terminated. Furthermore, if the number of iterations reaches a preset iteration threshold, the iteration is terminated even before convergence to the change threshold to ensure the algorithm's real-time performance. In practical applications, due to the relatively accurate initial values ​​and the fast convergence speed of the Newton-Raphson method, convergence is typically achieved after 2-4 iterations.

[0078] Step S130-2-5: Use the coordinates of the center position of the star spot obtained at the end of the iteration as the center position of the star spot that maximizes the probability of the pixel matrix appearing.

[0079] When the iteration terminates, the coordinates of the center positions of the star spots obtained from the last update are used as the final output. This result is what makes the joint probability density function... The parameter estimate that takes the maximum value is statistically optimal and unbiased, theoretically reaching the Cramer-Rhodes lower bound, i.e., the positioning accuracy limit. This result is better than the coarse estimate coordinates in step S110, and is therefore called "fine estimate coordinates".

[0080] The technical solution of this embodiment achieves high-precision dynamic star point positioning based on the effective line spread function. A joint probability density function is constructed based on the imaging physics model, transforming the positioning problem into a statistical inference problem. The optimal center position is solved using the maximum likelihood estimation method, and rapid iterative optimization via the Newton-Raphson method improves accuracy from coarse to fine estimation. This method fully utilizes the prior information of the tail energy distribution described by the effective line spread function, making the positioning results closer to the actual imaging physics process.

[0081] In an optional embodiment, the method further includes step S140: Step S140: During the measurement process, if the positioning accuracy of the effective line spread function does not meet the preset measurement requirements, the trailing parameters of the star spot are re-estimated and the effective line spread function is updated for positioning calculation.

[0082] In this embodiment, when the star sensor operates continuously under dynamic conditions, changes in its attitude may alter the motion state of the star spot. When the motion state changes, the effective line spread function established by the original trailing parameters will no longer accurately match the current imaging conditions. This embodiment introduces a model adaptive update mechanism (i.e., step S140 above) to ensure that the effective line spread function always matches the current motion state.

[0083] The preset measurement requirements include: when the change in the field of view angle of the star sensor corresponding to the range of motion of the star spot on the image plane exceeds a preset angle threshold, it is determined that the positioning accuracy does not meet the requirements. This preset measurement requirement is used to determine whether the current effective line spread function is still applicable. For example, the preset angle threshold can be 5 degrees, meaning that when the cumulative motion of the star spot on the image plane causes the corresponding change in the field of view angle of the star sensor to exceed 5 degrees, it is considered that the motion state has changed significantly and the model needs to be updated.

[0084] After determining that an update is needed, steps S110 to S120 are re-executed: the trailing parameters of the star spot are re-estimated, and the effective line spread function under the current motion conditions is re-established based on the static effective point spread function, and subsequent positioning calculations are continued.

[0085] Through the aforementioned adaptive update mechanism, this embodiment can automatically adjust the imaging model when the motion state of the star sensor changes, always maintaining the best match between the effective line spread function and the current imaging conditions, thereby ensuring that the dynamic star point positioning accuracy remains stable throughout the entire mission cycle.

[0086] The following specific embodiment illustrates the dynamic star point localization method based on the effective line spread function in this application. For example... Figure 4 As shown, Figure 4 This is a flowchart illustrating another dynamic star point localization method based on an effective line spread function provided in this application embodiment. Specifically, the method includes the following steps S410 to S490: Step S401: Construct a coordinate system for the star sensor image plane with the lower left corner vertex of the star sensor image plane as the origin, the horizontal direction of the image plane as the positive X-axis, and the vertical direction of the image plane as the positive Y-axis.

[0087] Step S402: Using the star sensor image plane coordinate system as a position reference, perform star map recognition on the star sky image, and use the threshold centroid method to calculate the center position coordinates of the star spot corresponding to the same navigation star in the current frame star sky image and the previous frame star sky image.

[0088] Step S403: Calculate the velocity vector of star spots on the image plane based on the sampling time interval between adjacent frames, the center position coordinates of the current frame star image, and the center position coordinates of the previous frame star image.

[0089] Step S404: Calculate the trail length based on the magnitude of the motion velocity vector and the exposure time of the star sensor.

[0090] Step S405: Determine the trailing direction based on the direction of the motion velocity vector; wherein the trailing direction is the angle between the motion velocity vector and the positive X-axis direction.

[0091] Step S406: Under static imaging conditions, acquire multi-frame average imaging data of point target spots at different sub-pixel positions on the image plane, establish the effective point spread function discrete sampling matrix of the star sensor, and interpolate the effective point spread function discrete sampling matrix using a two-dimensional interpolation method to obtain the effective point spread function.

[0092] Step S407: The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction.

[0093] Step S408: Based on the sub-pixel coordinates, calculate the arithmetic mean of the effective point spread functions at each discrete point on the trailing trajectory, and use it as the effective line spread function under the current motion conditions.

[0094] Step S409: Based on the effective line spread function, construct the joint probability density function of the pixel matrix within the region of interest for star spot imaging with respect to the center position of the star spot.

[0095] Step S4010: Using the maximum likelihood estimation method, the cost function derived from the joint probability density function is minimized through iterative optimization to obtain the center position of the star spot that maximizes the probability of the pixel matrix appearing, which is then used as the fine estimated coordinate of the star spot.

[0096] Step S41011: During the measurement process, determine whether the positioning accuracy of the effective line spread function meets the preset measurement requirements. If not, return to step S402, re-estimate the trailing parameters of the star spot and update the effective line spread function; if it meets the requirements, the dynamic star positioning is completed.

[0097] This embodiment achieves high-precision positioning of star spots under dynamic conditions through the coordinated operation of four major steps: motion parameter estimation, effective line spread function construction, maximum likelihood localization, and adaptive update. This provides reliable technical support for attitude measurement of star sensors in dynamic environments.

[0098] This application also provides a dynamic star point positioning device based on the effective line spread function, referring to... Figure 5 As shown, Figure 5 This is a schematic diagram of a dynamic star point positioning device based on an effective line spread function provided in an embodiment of this application. The device includes: The parameter estimation module 510 is used to estimate the trailing parameters of star spots based on the coarsely estimated coordinate position changes of star spots on adjacent frames of star sky images. The coarsely estimated coordinate position represents the center position coordinates of the star spots calculated by the threshold centroid method. The function establishment module 520 is used to establish an effective line spread function under the current motion conditions based on the effective point spread function established in advance under static imaging conditions and the tail parameters. The effective line spread function is used to characterize the energy distribution pattern of the trailing star spot obtained by integrating the effective point spread function along the trailing trajectory. The positioning calculation module 530 is used to perform positioning calculations on the imaging data of the star spot that forms a trailing pattern using the effective line spread function, so as to obtain the fine estimated coordinates of the star spot.

[0099] In an optional embodiment, the trailing parameters include trailing length and trailing direction; the parameter estimation module 510 is further configured to: A star sensor image plane coordinate system is constructed with the lower left corner vertex of the star sensor image plane as the origin, the horizontal direction of the image plane as the positive X-axis, and the vertical direction of the image plane as the positive Y-axis; the coordinate values ​​in the star sensor image plane coordinate system represent the position of the star spot in the pixel array. Using the star sensor image plane coordinate system as a position reference, star map recognition is performed on the star sky image, and the center position coordinates of the star point image spots corresponding to the same navigation star in the current frame star sky image and the previous frame star sky image are calculated using the threshold centroid method. The velocity vector of star spots on the image plane is calculated based on the sampling time interval between adjacent frames, the center position coordinates of the current frame star image, and the center position coordinates of the previous frame star image. The trail length is calculated based on the magnitude of the motion velocity vector and the exposure time of the star sensor; The trailing direction is determined based on the direction of the motion velocity vector; wherein, the trailing direction is the angle between the motion velocity vector and the positive X-axis direction.

[0100] In an optional embodiment, the function establishment module 520 is further configured to: Under static imaging conditions, multi-frame average imaging data of point target spots at different sub-pixel positions on the image plane are acquired, the effective point spread function discrete sampling matrix of the star sensor is established, and the effective point spread function is obtained by interpolating the effective point spread function discrete sampling matrix through a two-dimensional interpolation method. The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction; wherein, the number of discrete points is positively correlated with the trailing length. Based on the sub-pixel coordinates, the arithmetic mean of the effective point spread function at each discrete point on the trailing trajectory is calculated, which is used as the effective line spread function under the current motion conditions.

[0101] In an optional embodiment, the function establishment module 520 is further configured to: Using the midpoint of the trailing trajectory as a reference point, the trailing trajectory is divided into multiple discrete points at equal intervals along the trailing direction, and the position offset of each discrete point relative to the reference point is determined. The sub-pixel coordinates of each discrete point relative to the target pixel center are calculated based on the offset of the star spot center relative to the pixel center, the position offset, and the trailing direction.

[0102] In an optional embodiment, the positioning calculation module 530 is further configured to: Based on the effective line spread function, a joint probability density function of the pixel matrix within the region of interest in star spot imaging with respect to the center position of the star spot is constructed; The maximum likelihood estimation method is used to obtain the center position of the star spot that maximizes the probability of the pixel matrix by iteratively optimizing and minimizing the cost function derived from the joint probability density function. This position is then used as the fine-estimated coordinate of the star spot.

[0103] In an optional embodiment, the positioning calculation module 530 is further configured to: Taking the negative natural logarithm of the joint probability density function, a cost function is constructed regarding the center position of the star spot. Using the coarsely estimated coordinate position as the initial value for iteration, set the threshold for the number of iterations and the threshold for the iterative change of the star spot position coordinates; The cost function is iteratively optimized using the Newton-Raphson method, and the coordinates of the center position of the star spot are updated in each iteration. If the change in the coordinates of the center position of the star spot is less than the iteration change threshold during the iteration process, or if the number of iterations reaches the iteration number threshold, then the iteration is terminated. The coordinates of the star spot center obtained at the end of the iteration are taken as the star spot center position that maximizes the probability of the pixel matrix appearing.

[0104] In an optional embodiment, the device further includes: The update module, during the measurement process, if the positioning accuracy of the effective line spread function does not meet the preset measurement requirements, re-estimates the trailing parameters of the star spot and updates the effective line spread function to perform positioning calculations.

[0105] In one optional embodiment, the preset measurement requirement includes: when the change in the field of view angle of the star sensor corresponding to the range of motion of the star spot on the image plane exceeds a preset angle threshold, it is determined that the positioning accuracy does not meet the requirement.

[0106] It is understood that the dynamic star point positioning device based on the effective line diffusion function in the embodiments of this application can realize the dynamic star point positioning method based on the effective line diffusion function in the above embodiments. The dynamic star point positioning device based on the effective line diffusion function has the same advantages as the dynamic star point positioning method based on the effective line diffusion function in the prior art, and will not be repeated here.

[0107] This application also provides an electronic device, see embodiments thereof. Figure 6 , Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. For example... Figure 6 As shown, the electronic device 600 includes a memory 610 and a processor 620. The memory 610 and the processor 620 are connected via a bus for communication. The memory 610 stores a computer program that can run on the processor 620 to implement the steps of the dynamic star point positioning method based on the effective line spread function described in the embodiments of this application.

[0108] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the dynamic star point positioning method based on the effective line spread function described in this application.

[0109] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the dynamic star point positioning method based on the effective line spread function described in this application.

[0110] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0111] This application describes embodiments of methods and apparatus according to flowchart illustrations and / or block diagrams. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0112] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0114] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0115] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0116] The above provides a detailed description of a dynamic star point positioning method, apparatus, and device based on an effective line spread function provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A dynamic star point positioning method based on the effective line spread function, characterized in that, include: Based on the coarsely estimated coordinate position change of star spots in adjacent frames of star sky images, the trailing parameter of star spots is estimated. The coarsely estimated coordinate position represents the center position coordinates of star spots calculated by the threshold centroid method. Based on the effective point spread function established in advance under static imaging conditions, and combined with the trailing parameters, an effective line spread function under the current motion conditions is established. The effective line spread function is used to characterize the energy distribution pattern of the trailing star spot obtained by integrating the effective point spread function along the trailing trajectory. Using the effective line spread function, the imaging data of the star spot forming a trailing pattern is used to perform positioning calculations to obtain the fine estimated coordinates of the star spot.

2. The method according to claim 1, characterized in that, The trailing parameters include trailing length and trailing direction; based on the coarsely estimated coordinate position changes of star spots in adjacent frames of starscape images, the trailing parameters of star spots are estimated, including: A star sensor image plane coordinate system is constructed with the lower left corner vertex of the star sensor image plane as the origin, the horizontal direction of the image plane as the positive X-axis, and the vertical direction of the image plane as the positive Y-axis; the coordinate values ​​in the star sensor image plane coordinate system represent the position of the star spot in the pixel array. Using the star sensor image plane coordinate system as a position reference, star map recognition is performed on the star sky image, and the center position coordinates of the star point image spots corresponding to the same navigation star in the current frame star sky image and the previous frame star sky image are calculated using the threshold centroid method. The velocity vector of star spots on the image plane is calculated based on the sampling time interval between adjacent frames, the center position coordinates of the current frame star image, and the center position coordinates of the previous frame star image. The trail length is calculated based on the magnitude of the motion velocity vector and the exposure time of the star sensor; The trailing direction is determined based on the direction of the motion velocity vector; wherein, the trailing direction is the angle between the motion velocity vector and the positive X-axis direction.

3. The method according to claim 2, characterized in that, Based on the effective point spread function pre-established under static imaging conditions, and incorporating the trailing parameters, an effective line spread function is established under the current motion conditions, including: Under static imaging conditions, multi-frame average imaging data of point target spots at different sub-pixel positions on the image plane are acquired, the effective point spread function discrete sampling matrix of the star sensor is established, and the effective point spread function is obtained by interpolating the effective point spread function discrete sampling matrix through a two-dimensional interpolation method. The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction; wherein, the number of discrete points is positively correlated with the trailing length. Based on the sub-pixel coordinates, the arithmetic mean of the effective point spread function at each discrete point on the trailing trajectory is calculated, which is used as the effective line spread function under the current motion conditions.

4. The method according to claim 3, characterized in that, The trailing trajectory determined by the trailing parameters is uniformly discretized into multiple points, and the sub-pixel coordinates of each discrete point relative to the pixel center are calculated based on the position of each discrete point on the trailing trajectory and the trailing direction, including: Using the midpoint of the trailing trajectory as a reference point, the trailing trajectory is divided into multiple discrete points at equal intervals along the trailing direction, and the position offset of each discrete point relative to the reference point is determined. The sub-pixel coordinates of each discrete point relative to the target pixel center are calculated based on the offset of the star spot center relative to the pixel center, the position offset, and the trailing direction.

5. The method according to claim 1, characterized in that, Using the effective line spread function, the imaging data of the star-shaped image spots forming a trailing pattern are used to perform localization calculations to obtain a fine estimate of the coordinates of the star-shaped image spots, including: Based on the effective line spread function, a joint probability density function of the pixel matrix within the region of interest in star spot imaging with respect to the center position of the star spot is constructed; The maximum likelihood estimation method is used to obtain the center position of the star spot that maximizes the probability of the pixel matrix by iteratively optimizing and minimizing the cost function derived from the joint probability density function. This position is then used as the fine-estimated coordinate of the star spot.

6. The method according to claim 5, characterized in that, The maximum likelihood estimation method is used to obtain the center position of the star spot that maximizes the probability of the pixel matrix by iteratively minimizing the cost function derived from the joint probability density function, including: Taking the negative natural logarithm of the joint probability density function, a cost function is constructed regarding the center position of the star spot. Using the coarsely estimated coordinate position as the initial value for iteration, set the threshold for the number of iterations and the threshold for the iterative change of the star spot position coordinates; The cost function is iteratively optimized using the Newton-Raphson method, and the coordinates of the center position of the star spot are updated in each iteration. If the change in the coordinates of the center position of the star spot is less than the iteration change threshold during the iteration process, or if the number of iterations reaches the iteration number threshold, then the iteration is terminated. The coordinates of the star spot center obtained at the end of the iteration are taken as the star spot center position that maximizes the probability of the pixel matrix appearing.

7. The method according to claim 1, characterized in that, The method further includes: During the measurement process, if the positioning accuracy of the effective line spread function does not meet the preset measurement requirements, the trailing parameters of the star spot are re-estimated and the effective line spread function is updated for positioning calculation.

8. The method according to claim 7, characterized in that, The preset measurement requirements include: when the change in the field of view angle of the star sensor corresponding to the range of motion of the star spot on the image plane exceeds a preset angle threshold, it is determined that the positioning accuracy does not meet the requirements.

9. A dynamic star point positioning device based on an effective line spread function, characterized in that, include: The parameter estimation module is used to estimate the trailing parameters of star spots based on the coarsely estimated coordinate position changes of star spots in adjacent frames of star sky images. The coarsely estimated coordinate position represents the center position coordinates of the star spots calculated by the threshold centroid method. The function establishment module is used to establish an effective line spread function under the current motion conditions based on the effective point spread function established in advance under static imaging conditions and the tail parameters. The effective line spread function is used to characterize the energy distribution pattern of the trailing star spot obtained by integrating the effective point spread function along the trailing trajectory. The positioning calculation module is used to perform positioning calculations on the imaging data of the star spot that forms a trailing pattern using the effective line spread function, so as to obtain the fine estimated coordinates of the star spot.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the dynamic star point positioning method based on the effective line spread function as described in any one of claims 1-8.

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