Agile optical satellite geometric external calibration method based on moon observation

Abstract

The embodiment of the invention discloses an agile optical satellite geometric external calibration method based on moon observation, and relates to the technical field of optical satellite data processing, and the method comprises the steps: obtaining a moon observation image shot by a to-be-calibrated optical satellite, and determining a lunar surface control point on the moon observation image; according to a lunar observation imaging mechanism of an optical satellite, constructing a lunar observation geometric calibration model considering light traveling time and aberration correction; and resolving the moon observation geometric calibration model through the plurality of lunar surface control points, and updating according to a resolving result to obtain camera installation parameters. According to the method, error sources such as the aberration and the light traveling time are comprehensively considered, the moon observation geometric calibration model considering the light traveling time and aberration correction is constructed, and camera installation parameters are solved by using the lunar surface control point, so that geometric external calibration processing of the agile optical satellite is realized, and the accuracy of the geometric external calibration of the agile optical satellite is improved. The method can effectively make up the defects of an on-orbit geometric calibration method based on a ground calibration field, and provides support for high-precision geometric positioning of an optical satellite.

Description

Technical Field

[0001] This application relates to the field of optical satellite data processing technology, and in particular to an agile optical satellite geometric external calibration method based on lunar observation. Background Technology

[0002] During their on-orbit operation, the imaging payloads of optical satellites are susceptible to changes in the space environment, satellite platform jitter, and equipment performance degradation, causing variations in the installation parameters of Earth observation cameras. To improve the direct positioning accuracy of optical satellite images, related technologies typically use high-precision control data from ground calibration fields to periodically or on-demand update the camera installation parameters. However, this approach is highly dependent on the global distribution of ground calibration fields and is easily limited by factors such as satellite orbit and observation weather, making it difficult to acquire high-quality optical satellite images covering ground calibration fields in a timely manner.

[0003] To compensate for the shortcomings of on-orbit geometric calibration methods based on ground calibration fields, some related technologies can be implemented by mounting high-precision angle detectors on satellites to measure the angle between the optical axis of the star sensor and the optical axis of the Earth observation camera in real time, i.e., the camera installation parameters. However, this approach is only applicable to certain satellites, and carrying additional equipment would incur higher costs.

[0004] In addition, some related technologies can also improve the agile maneuvering imaging capabilities of optical satellites. By simultaneously observing and imaging stars through star sensors and Earth observation cameras, and using stars as high-precision control points, the camera installation parameters can be updated in real time. However, since stars are point light sources, the imaging capabilities of the satellite are more demanding, and the number of bright stars that can be used is small and unevenly distributed, resulting in insufficient reliability in calculations.

[0005] Therefore, there is currently a lack of a method that can accurately update camera installation parameters in real time. Summary of the Invention

[0006] This application provides an agile optical satellite geometric external calibration method based on lunar observation to address the deficiencies in related technologies. The technical solution is as follows: In a first aspect, embodiments of this application provide a method for geometric external calibration of agile optical satellites based on lunar observations, the method comprising: Acquire lunar observation images taken by the optical satellite to be calibrated, and determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data; Based on the imaging mechanism of lunar observation by optical satellites, and combining the lunar surface points on the lunar observation images, the orbital parameters of the optical satellites, the initial camera parameters, the lunar parameters, and the Earth parameters, a geometric calibration model for lunar observation that takes into account the correction of optical travel time and optical travel aberration is constructed. The lunar observation geometric calibration model is solved using multiple lunar surface control points, and the camera installation parameters of the optical satellite are updated based on the solution results.

[0007] In one alternative of the first aspect, before constructing the lunar observation geometric calibration model that takes into account optical travel time and optical aberration corrections by combining lunar surface points, optical satellite orbital parameters, initial camera parameters, lunar parameters, and Earth parameters, the method further includes: The position and velocity of the optical satellite in the geocentric inertial coordinate system at the imaging moment are determined based on the optical satellite's orbital parameters. Determine the position of a point on the lunar surface in the lunar-Earth / lunar-rotational coordinate system; Determine the emission time of the imaging ray at the lunar surface point, and determine the position and velocity of the Moon in the geocentric inertial coordinate system at the emission time; The satellite body coordinate system and the camera coordinate system are established based on the optical satellite orbit parameters and the initial camera parameters; Based on the lunar parameters and the Earth parameters, determine the rotation matrix from the geocentric inertial coordinate system to the lunar inertial coordinate system, the rotation matrix from the lunar inertial coordinate system to the geocentric inertial coordinate system, the rotation matrix from the lunar inertial coordinate system at the time of transmission to the lunar-Earth / horizontal rotation axis coordinate system, and the rotation matrix from the lunar-Earth / horizontal rotation axis coordinate system at the time of transmission to the lunar inertial coordinate system. Based on the initial camera parameters, a rotation matrix from the satellite body coordinate system to the camera coordinate system is constructed. Based on the position and velocity of the optical satellite in the geocentric inertial coordinate system at the imaging time, combined with the Earth parameters, the rotation matrix from the geocentric inertial coordinate system to the satellite body coordinate system is determined.

[0008] In one alternative of the first aspect, the lunar observation geometric calibration model, which takes into account optical travel time and optical aberration corrections, is constructed by combining lunar surface points, optical satellite orbital parameters, initial camera parameters, lunar parameters, and Earth parameters, including: Calculate the observation vector from the optical satellite to the lunar control point in the lunar-Earth / lunar-rotation axis coordinate system. Apply the formula: ; Transform the observation view vector to the geocentric inertial coordinate system to obtain the observation view vector in the geocentric inertial coordinate system. Apply the formula: ; The object-side observation view vector is corrected for axial aberration to obtain the corrected observation view vector. Apply the formula: ; Determine the image point of the lunar surface point in the lunar observation image, and obtain the image-side observation view vector of the image point in the camera coordinate system. ; A geometric calibration model for lunar observations, taking into account corrections for optical travel time and optical aberration, is constructed by applying the following formula: ; Wherein, MER represents the lunar-Earth / lunar rotation axis coordinate system, MCI represents the lunar-centric inertial coordinate system, ECI represents the geocentric inertial coordinate system, Cam represents the camera coordinate system, and Body represents the satellite body coordinate system; Let P be the coordinates of a point on the lunar surface in MER. The time of issuance, The imaging time; for The rotation matrix from MCI to MER at time step; This is the rotation matrix from ECI to MCI; for The position of the optical satellite in the geocentric inertial coordinate system at any given time; for The Moon's position within the ECI at any given time; This is the rotation matrix from MCI to ECI; for The rotation matrix from MER to MCI at time 1; The velocity of the optical satellite under ECI; The speed of the moon under ECI; The speed of light; It is a scaling factor; Let be the rotation matrix from Body to Cam; for The rotation matrix from ECI to Body at time step ECI.

[0009] In one alternative embodiment of the first aspect, the step of solving the lunar observation geometric calibration model using multiple lunar surface control points includes: The image-side coordinates and object-side coordinates of multiple lunar control points are input in pairs into the lunar observation geometric calibration model. Iterative calculations are performed with the preset launch time as the initial value. If the results of the iterative calculations meet the preset conditions, the launch time corresponding to each lunar control point is output. The observation vector is updated based on the emission time of each lunar control point. The observation view vector The error equation is constructed by combining the aforementioned geometric calibration model for lunar observation; Based on the principle of least squares adjustment, the error equation is solved to calculate the camera mounting parameter correction.

[0010] In one alternative to the first aspect, the iterative calculation process applies the following formula: ; Determining whether the result obtained in the current iteration satisfies the preset conditions includes: If the difference between the emission time obtained in the current iteration and the emission time obtained in the previous iteration is less than a preset difference threshold, then the preset condition is met and the iteration stops. Output the emission time obtained in the current iteration; Where s represents the number of iterations.

[0011] In one alternative to the first aspect, the process of constructing the error equation includes: make ; ; ; The lunar observation geometric calibration model is rewritten in the following form: ; The error equations were constructed by combining the revised lunar observation geometric calibration model, including: ; ; ; ; ; Wherein, the subscript i represents the i-th lunar control point; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; The residual matrix of lunar control points. This represents the x-component of the residual at lunar control point i. This represents the component of the residual of lunar control point i in the y-direction; The design matrix is ​​composed of the partial derivatives of the camera mounting parameters; A correction matrix for camera mounting parameters; It is a matrix of constant terms.

[0012] In one alternative to the first aspect, the error equation is solved according to the least squares adjustment principle, using the formula: ; Calculate the camera mounting parameter corrections ; The step of updating the camera installation parameters of the optical satellite based on the calculation results includes: Update the camera installation parameters based on the camera parameter corrections. If the adjustment iteration fails to converge, then proceed to update the observation view vector based on the emission time of each lunar control point. The observation view vector Steps; If the adjustment iteration converges, the converged camera installation parameters are output.

[0013] Secondly, embodiments of this application also provide an agile optical satellite geometric external calibration device based on lunar observation, comprising: The control point measurement unit is used to acquire lunar observation images taken by the optical satellite to be calibrated, and to determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data. The geometric calibration modeling unit is used to construct a geometric calibration model for lunar observation that takes into account the correction of optical travel time and optical travel aberration, based on the imaging mechanism of optical satellite lunar observation and in combination with lunar surface points on the lunar observation image, optical satellite orbital parameters, initial camera parameters, lunar parameters and Earth parameters. The camera installation parameter calculation unit is used to solve the lunar observation geometric calibration model through multiple lunar surface control points, and update the camera installation parameters of the optical satellite based on the solution results.

[0014] Thirdly, embodiments of this application also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method provided by the first aspect or any implementation thereof of the embodiments of this application.

[0015] Fourthly, this application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method provided by the first aspect of the embodiments of this application or any implementation thereof.

[0016] The beneficial effects of the technical solutions provided in some embodiments of this application include at least the following: This application first obtains lunar control points on lunar observation images from high-precision lunar reference data. Second, based on the imaging mechanism of optical satellite lunar observation, it comprehensively considers the influence of error sources such as optical aberration and optical timing, and constructs a lunar observation geometric calibration model that takes into account corrections for optical timing and optical aberration. Then, based on the lunar observation geometric calibration model, it uses lunar control points to calculate the corrections for camera installation parameters, and then iteratively updates the initial camera parameters until the adjustment iteration converges, thus obtaining the accurate camera installation parameters of the optical satellite. This application, combined with the rapid maneuvering imaging capability of the agile optical satellite, updates camera installation parameters in real time through lunar control points, effectively compensating for the shortcomings of on-orbit geometric calibration methods based on ground calibration fields, and providing support for high-precision geometric positioning of optical satellites. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating an agile optical satellite geometric external calibration method based on lunar observation, provided in an embodiment of this application. Figure 2 This is a schematic diagram of the structure of an agile optical satellite geometry external calibration device based on lunar observation, provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions 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 of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or modules is not limited to the steps or modules listed, but may optionally include steps or modules not listed, or may optionally include other steps or modules inherent to such process, method, product, or apparatus.

[0021] It should be noted that the terms "first" and "second" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that "first" and "second" can be interchanged in a specific order or sequence where permitted. It should be understood that the objects distinguished by "first" and "second" can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in an order other than those described or illustrated herein.

[0022] It should be noted that, with the continuous improvement of the agile maneuvering imaging capabilities of optical satellites, lunar observation and imaging can be performed through the Earth observation camera on the optical satellite. The embodiments of this application can provide high-precision control information through lunar surface points.

[0023] Compared to Earth observation imaging, lunar observation imaging by optical satellites is affected by error sources such as optical aberration and optical timing. The embodiments of this application fully consider these possible error sources, thereby obtaining accurate camera installation parameters and achieving precise geometric external calibration.

[0024] The present application will now be described in detail with reference to specific embodiments.

[0025] Next, combine Figure 1 This application introduces an agile optical satellite geometric external calibration method based on lunar observation, as provided in its embodiments. For details, please refer to... Figure 1 , Figure 1 This document illustrates a flowchart of an agile optical satellite geometry external calibration method based on lunar observations, provided in an embodiment of this application. Figure 1 As shown, the method includes the following steps: S101, acquire lunar observation images taken by the optical satellite to be calibrated, and determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data; S102. Based on the imaging mechanism of optical satellite lunar observation, and combined with the lunar surface points on the lunar observation image, optical satellite orbital parameters, initial camera parameters, lunar parameters, and Earth parameters, a geometric calibration model for lunar observation that takes into account optical travel time and optical travel aberration correction is constructed. S103, the lunar observation geometric calibration model is solved using multiple lunar surface control points, and the camera installation parameters of the optical satellite are updated based on the solution results.

[0026] Specifically, in S101, multiple lunar control points can be determined based on publicly available high-precision lunar surface reference data, and the actual coordinate positions of the lunar control points, i.e., the object coordinates of the lunar control points, can be determined. Next, the corresponding position of each lunar control point in the lunar observation image can be determined, i.e., the image coordinates of the lunar control points. Based on this, each lunar control point has object coordinates in the real world and image coordinates in the lunar observation image.

[0027] In some embodiments, before constructing the lunar observation geometric calibration model that takes into account the optical travel time and optical travel aberration correction as described in S102 by combining lunar surface points, optical satellite orbit parameters, initial camera parameters, lunar parameters, and Earth parameters, the data used to construct the model can be determined based on these parameters.

[0028] It should be noted that a lunar point can be any point on the lunar surface, or any point other than a lunar control point, and has known object-space coordinates and image-space coordinates.

[0029] Specifically, the imaging time can be determined based on the optical satellite's orbital parameters. Position of optical satellites in Earth-Centered Inertial (ECI) coordinate system and speed ; Determine the position of point P on the lunar surface in the Moon Equator of Date / Mean Earth / Rotation (MER) coordinate system. ; Determine the emission time of the imaging ray from point P on the lunar surface. Determine the time of transmission The position of the Moon in the geocentric inertial coordinate system and speed ; The satellite body coordinate system and the camera coordinate system are established based on the optical satellite orbit parameters and the initial camera parameters; Based on the lunar parameters and the Earth parameters, determine the rotation matrix from the geocentric inertial coordinate system to the lunar-centered inertial coordinate system (MCI), the rotation matrix from the lunar-centered inertial coordinate system to the geocentric inertial coordinate system, and the emission time. The rotation matrix from the lunar inertial coordinate system to the lunar-Earth / lunar rotation axis coordinate system, and the time of issuance. Rotation matrix from the lunar-Earth / lunar rotation axis coordinate system to the lunar-centric inertial coordinate system; Based on the initial camera parameters, a rotation matrix from the satellite body coordinate system to the camera coordinate system is constructed, and based on the imaging time... The position and velocity of the optical satellite in the geocentric inertial coordinate system, combined with the Earth parameters, determine the rotation matrix from the geocentric inertial coordinate system to the satellite's body coordinate system.

[0030] It should be noted that lunar parameters may include lunar-related parameters such as libration, which are used to construct the rotation matrix from the lunar-centric inertial coordinate system to the lunar-to-Earth / to-rotation axis coordinate system, and the rotation matrix from the lunar-to-Earth / to-rotation axis coordinate system to the lunar-centric inertial coordinate system; Earth parameters may include parameters such as precession, nutation, polar motion, and rotation, which can be used to construct the rotation matrix from the geocentric inertial coordinate system to the satellite's body coordinate system.

[0031] Next, in step S102, a geometric calibration model for lunar observation that takes into account optical travel time and optical aberration corrections can be constructed by combining lunar surface points, optical satellite orbital parameters, initial camera parameters, lunar parameters, and Earth parameters, including: Calculate the observation vector from the optical satellite to the lunar control point in the lunar-Earth / lunar-rotation axis coordinate system. Apply the formula: ; Transform the observation view vector to the geocentric inertial coordinate system to obtain the observation view vector in the geocentric inertial coordinate system. Apply the formula: ; The object-side observation view vector is corrected for axial aberration to obtain the corrected observation view vector. Apply the formula: ; Determine the image point of the lunar surface point in the lunar observation image, and obtain the image-side observation view vector of the image point in the camera coordinate system. ; A geometric calibration model for lunar observations, taking into account corrections for optical travel time and optical aberration, is constructed by applying the following formula: ; Wherein, MER represents the lunar-Earth / lunar rotation axis coordinate system, MCI represents the lunar-centric inertial coordinate system, ECI represents the geocentric inertial coordinate system, Cam represents the camera coordinate system, and Body represents the satellite body coordinate system; Let P be the coordinates of a point on the lunar surface in MER. The time of issuance, The imaging time; for The rotation matrix from MCI to MER at time step; This is the rotation matrix from ECI to MCI; for The position of the optical satellite in the geocentric inertial coordinate system at any given time; for The Moon's position within the ECI at any given time; This is the rotation matrix from MCI to ECI; for The rotation matrix from MER to MCI at time 1; The velocity of the optical satellite under ECI; The speed of the moon under ECI; The speed of light; It is a scaling factor; Let be the rotation matrix from Body to Cam; for The rotation matrix from ECI to Body at time step ECI.

[0032] Specifically, in S103, the lunar observation geometric calibration model is solved using multiple lunar surface control points, including: S1031, input the image-side coordinates and object-side coordinates of multiple lunar control points in pairs into the lunar observation geometric calibration model, perform iterative calculations using a preset launch time as the initial value, and output the launch time corresponding to each lunar control point if the results of the iterative calculations meet preset conditions. .

[0033] The preset emission time can be set to 1.2 seconds based on experience. S1032, based on the transmission time of each lunar control point Update the observation view vector The observation view vector The error equation is constructed by combining the aforementioned geometric calibration model for lunar observation; S1033 solves the error equation based on the least squares adjustment principle and calculates the camera mounting parameter correction.

[0034] In some embodiments, S1031, the process of iteratively calculating the departure time corresponding to each lunar control point applies the following formula: ; Determining whether the result obtained in the current iteration satisfies the preset conditions includes: If the emission time obtained in the current iteration update The emission time obtained from the previous iteration If the difference is less than the preset difference threshold, then the preset condition is met and the iteration stops; Output the emission time obtained in the current iteration. ; Where s represents the number of iterations.

[0035] Specifically, in S1032, it can be based on the observation view vector. Observational view vector And a geometric calibration model for lunar observations was used to construct error equations, specifically including: make ; ; ; The lunar observation geometric calibration model is rewritten in the following form: ; The constructed error equations include: ; ; ; ; ; Wherein, the subscript i represents the i-th lunar control point; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; The residual matrix of lunar control points. This represents the x-component of the residual at lunar control point i. This represents the component of the residual of lunar control point i in the y-direction; The design matrix is ​​composed of the partial derivatives of the camera mounting parameters; A correction matrix for camera mounting parameters; It is a matrix of constant terms.

[0036] Specifically, in S1033, the error equation can be solved according to the least squares adjustment principle, using the following formula: ; Calculate the camera mounting parameter corrections ; The step of updating the camera installation parameters of the optical satellite based on the calculation results includes: Update the camera installation parameters based on the camera parameter corrections. If the adjustment iteration does not converge, proceed to step S1032 to update the observation view vector based on the emission time of each lunar control point. The observation view vector The steps are repeated iteratively. If the adjustment iteration converges, the converged camera installation parameters are output.

[0037] In this manner, the embodiments of this application first obtain lunar surface control points on lunar observation images from high-precision lunar surface reference data; secondly, based on the imaging mechanism of lunar observation by optical satellites, a lunar observation geometric calibration model that takes into account optical travel time and optical travel difference correction is constructed; then, based on the lunar observation geometric calibration model, using lunar surface control points, the corrections for camera installation parameters are calculated, and then iteratively updated based on the initial camera parameters until the adjustment iteration converges, thus obtaining the accurate camera installation parameters of the optical satellite; the embodiments of this application, combined with the rapid maneuvering imaging capability of agile optical satellites, update camera installation parameters in real time through lunar surface control points, which can effectively make up for the shortcomings of on-orbit geometric calibration methods based on ground calibration fields, and provide support for high-precision geometric positioning of optical satellites.

[0038] The following are device embodiments of this application, which can be used to execute the method embodiments of this application. For details not disclosed in the device embodiments of this application, please refer to the method embodiments of this application.

[0039] Please see below. Figure 2 The image below is a schematic diagram of a geometric external calibration device for an agile optical satellite based on lunar observation, provided as an exemplary embodiment of this application. The device includes: The control point measurement unit is used to acquire lunar observation images taken by the optical satellite to be calibrated, and to determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data. The geometric calibration modeling unit is used to construct a geometric calibration model for lunar observation that takes into account the correction of optical travel time and optical travel aberration, based on the imaging mechanism of optical satellite lunar observation and in combination with lunar surface points on the lunar observation image, optical satellite orbital parameters, initial camera parameters, lunar parameters and Earth parameters. The camera installation parameter calculation unit is used to solve the lunar observation geometric calibration model through multiple lunar surface control points, and update the camera installation parameters of the optical satellite based on the solution results.

[0040] It should be noted that the apparatus provided in the above embodiments, when executing an agile optical satellite geometric external calibration method based on lunar observation, is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. Furthermore, the apparatus provided in the above embodiments and the embodiment of the agile optical satellite geometric external calibration method based on lunar observation belong to the same concept, and its implementation process is detailed in the method embodiment, which will not be repeated here.

[0041] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the methods described above.

[0042] Please see Figure 3 This is a structural block diagram of an electronic device provided in an embodiment of this application.

[0043] like Figure 3 As shown, the electronic device 300 includes a processor 301 and a memory 302.

[0044] In this embodiment, the processor 301 is the control center of the computer system, and can be a processor of a physical machine or a processor of a virtual machine. The processor 301 may include one or more processing cores, such as a 4-core processor or an 8-core processor. The processor 301 can be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array).

[0045] Processor 301 may also include a main processor and a coprocessor. The main processor is a processor used to process data in the wake-up state, also known as a CPU (Central Processing Unit). The coprocessor is a low-power processor used to process data in the standby state.

[0046] Memory 302 may include one or more computer-readable storage media, which may be non-transitory. Memory 302 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments of this application, the non-transitory computer-readable storage media in memory 302 is used to store at least one instruction, which is executed by processor 301 to implement the method in the embodiments of this application.

[0047] In some embodiments, the electronic device 300 further includes a peripheral device interface 303 and at least one peripheral device 304. The processor 301, memory 302, and peripheral device interface 303 can be connected via a bus or signal line. Each peripheral device 304 can be connected to the peripheral device interface 303 via a bus, signal line, or circuit board. Specifically, the peripheral device 304 includes: a display screen, a camera, and audio circuitry. The peripheral device interface 303 can be used to connect at least one I / O (Input / Output) related peripheral device to the processor 301 and memory 302.

[0048] In some embodiments of this application, the processor 301, memory 302, and peripheral device interface 303 are integrated on the same chip or circuit board; in other embodiments of this application, any one or two of the processor 301, memory 302, and peripheral device interface 303 can be implemented on separate chips or circuit boards. This application does not specifically limit the implementation in this regard.

[0049] The electronic device structural block diagram shown in the embodiments of this application does not constitute a limitation on the electronic device 300. The electronic device 300 may include more or fewer components than shown, or combine certain components, or use different component arrangements.

[0050] 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 methods in any of the foregoing embodiments. The computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives, as well as magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0051] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for geometric external calibration of agile optical satellites based on lunar observation, characterized in that, include: Acquire lunar observation images taken by the optical satellite to be calibrated, and determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data; Based on the imaging mechanism of lunar observation by optical satellites, and combining the lunar surface points on the lunar observation images, the orbital parameters of the optical satellites, the initial camera parameters, the lunar parameters, and the Earth parameters, a geometric calibration model for lunar observation that takes into account the correction of optical travel time and optical travel aberration is constructed. The lunar observation geometric calibration model is solved using multiple lunar surface control points, and the camera installation parameters of the optical satellite are updated based on the solution results.

2. The agile optical satellite geometric external calibration method based on lunar observation according to claim 1, characterized in that, Before constructing the lunar observation geometric calibration model that takes into account optical travel time and optical aberration correction by combining lunar surface points, optical satellite orbit parameters, initial camera parameters, lunar parameters, and Earth parameters, the method further includes: The position and velocity of the optical satellite in the geocentric inertial coordinate system at the imaging moment are determined based on the optical satellite's orbital parameters. Determine the position of a point on the lunar surface in the lunar-Earth / lunar-rotational coordinate system; Determine the emission time of the imaging ray at the lunar surface point, and determine the position and velocity of the Moon in the geocentric inertial coordinate system at the emission time; The satellite body coordinate system and the camera coordinate system are established based on the optical satellite orbit parameters and the initial camera parameters; Based on the lunar parameters and the Earth parameters, determine the rotation matrix from the geocentric inertial coordinate system to the lunar inertial coordinate system, the rotation matrix from the lunar inertial coordinate system to the geocentric inertial coordinate system, the rotation matrix from the lunar inertial coordinate system at the time of transmission to the lunar-Earth / horizontal rotation axis coordinate system, and the rotation matrix from the lunar-Earth / horizontal rotation axis coordinate system at the time of transmission to the lunar inertial coordinate system. Based on the initial camera parameters, a rotation matrix from the satellite body coordinate system to the camera coordinate system is constructed. Based on the position and velocity of the optical satellite in the geocentric inertial coordinate system at the imaging time, combined with the Earth parameters, the rotation matrix from the geocentric inertial coordinate system to the satellite body coordinate system is determined.

3. The agile optical satellite geometric external calibration method based on lunar observation according to claim 2, characterized in that, The geometric calibration model for lunar observation, which incorporates lunar surface points, optical satellite orbital parameters, initial camera parameters, lunar parameters, and Earth parameters and takes into account optical travel time and optical aberration corrections, includes: Calculate the observation vector from the optical satellite to the lunar control point in the lunar-Earth / lunar-rotation axis coordinate system. Apply the formula: ； Transform the observation view vector to the geocentric inertial coordinate system to obtain the observation view vector in the geocentric inertial coordinate system. Apply the formula: ； The object-side observation view vector is corrected for axial aberration to obtain the corrected observation view vector. Apply the formula: ； Determine the image point of the lunar surface point in the lunar observation image, and obtain the image-side observation view vector of the image point in the camera coordinate system. ; A geometric calibration model for lunar observations, taking into account corrections for optical travel time and optical aberration, is constructed by applying the following formula: ； Where MER represents the lunar-Earth / lunar rotation axis coordinate system, MCI represents the lunar-centric inertial coordinate system, ECI represents the geocentric inertial coordinate system, Cam represents the camera coordinate system, and Body represents the satellite body coordinate system; Let P be the coordinates of a point on the lunar surface in MER. The time of issuance, The imaging time; for The rotation matrix from MCI to MER at time step; This is the rotation matrix from ECI to MCI; for The position of the optical satellite in the geocentric inertial coordinate system at any given time; for The Moon's position within the ECI at any given time; This is the rotation matrix from MCI to ECI; for The rotation matrix from MER to MCI at time 1; The velocity of the optical satellite under ECI; The speed of the moon under ECI; The speed of light; It is a scaling factor; Let be the rotation matrix from Body to Cam; for The rotation matrix from ECI to Body at time step ECI.

4. The method according to claim 3, characterized in that, The process of solving the lunar observation geometric calibration model using multiple lunar surface control points includes: The image-side coordinates and object-side coordinates of multiple lunar control points are input in pairs into the lunar observation geometric calibration model. Iterative calculations are performed with the preset launch time as the initial value. If the results of the iterative calculations meet the preset conditions, the launch time corresponding to each lunar control point is output. The observation vector is updated based on the emission time of each lunar control point. The observation view vector The error equation is constructed by combining the aforementioned geometric calibration model for lunar observation; Based on the principle of least squares adjustment, the error equation is solved to calculate the camera mounting parameter correction.

5. The method according to claim 4, characterized in that, The iterative calculation process uses the following formula: ； Determining whether the result obtained in the current iteration satisfies the preset conditions includes: If the difference between the emission time obtained in the current iteration and the emission time obtained in the previous iteration is less than a preset difference threshold, then the preset condition is met and the iteration stops. Output the emission time obtained in the current iteration; Where s represents the number of iterations.

6. The method according to claim 4, characterized in that, The method further includes: make ; ； ； The lunar observation geometric calibration model is rewritten in the following form: ； The error equations were constructed by combining the revised lunar observation geometric calibration model, including: ； ； ； ； ； Wherein, the subscript i represents the i-th lunar control point; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; For the observation view vector The component in the x-direction, For the observation view vector The component in the y-direction, For the observation view vector The component in the z-direction; The residual matrix of lunar control points. This represents the x-component of the residual at lunar control point i. This represents the component of the residual of lunar control point i in the y-direction; The design matrix is ​​composed of the partial derivatives of the camera mounting parameters; A correction matrix for camera mounting parameters; It is a matrix of constant terms.

7. The method according to claim 6, characterized in that, The error equation is solved according to the least squares adjustment principle, using the following formula: ； Calculate the camera mounting parameter corrections ; The step of updating the camera installation parameters of the optical satellite based on the calculation results includes: Update the camera installation parameters based on the camera parameter corrections. If the adjustment iteration fails to converge, then proceed to update the observation view vector based on the emission time of each lunar control point. The observation view vector Steps; If the adjustment iteration converges, the converged camera installation parameters are output.

8. A geometric external calibration device for agile optical satellites based on lunar observation, characterized in that, include: The control point measurement unit is used to acquire lunar observation images taken by the optical satellite to be calibrated, and to determine lunar surface control points on the lunar observation images based on high-precision lunar surface reference data. The geometric calibration modeling unit is used to construct a geometric calibration model for lunar observation that takes into account the correction of optical travel time and optical travel aberration, based on the imaging mechanism of optical satellite lunar observation and in combination with lunar surface points on the lunar observation image, optical satellite orbital parameters, initial camera parameters, lunar parameters and Earth parameters. The camera installation parameter calculation unit is used to solve the lunar observation geometric calibration model through multiple lunar surface control points, and update the camera installation parameters of the optical satellite based on the solution results.

9. 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 program, it implements the steps of the method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

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