Geometric recalibration method and device based on star group time sequence image and electronic equipment

Abstract

The invention provides a geometric recalibration method and device based on a star group time sequence image and electronic equipment, and relates to the technical field of satellite data processing.The geometric recalibration method based on the star group time sequence image comprises the steps that the long-period included angle variable quantity between any two star sensors is counted according to time sequence observation vectors of the star sensors, and the time sequence observation vectors of the star sensors are calculated according to the long-period included angle variable quantity; decomposing the variable quantity of the included angle into a three-axis attitude change angle; performing aberration compensation according to the original data of the star sensor, and determining a three-axis attitude correction value; determining a three-axis optimized attitude angle based on the three-axis attitude change angle and the three-axis attitude correction value of the long-period change of the included angle; and a re-calibration model is determined according to the three-axis optimization attitude angle, and the re-calibration model is solved to obtain an optimal calibration model for image calibration, so that the technical problem of space reference change of the satellite group long-time sequence image in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of satellite data processing, and in particular, to a geometric recalibration method, device and electronic device based on constellation time-series images. Background Art

[0002] Before a satellite is launched, strict laboratory calibration of on-board payload parameters is carried out. However, due to factors such as changes in the space environment during satellite launch and operation, the structure and state of the on-board payload change, resulting in a large error between the laboratory calibration parameters and the true parameters after being on orbit.

[0003] As the time span increases, the differences in orbital measurement factors, attitude measurement factors, time factors, space environment factors, etc. of the geometric quality of the constellation sequence satellite images will also increase. This will inevitably introduce systematic errors, reduce the geometric positioning accuracy of the images, and the inconsistency of the spatial reference will be more serious. Summary of the Invention

[0004] The present application aims to at least solve one of the technical problems in the related art to some extent.

[0005] To this end, the first object of the present application is to propose a geometric recalibration method based on constellation time-series images to improve the geometric positioning accuracy of the images and accurately analyze constellation images.

[0006] The second object of the present application is to propose a geometric recalibration device based on constellation time-series images.

[0007] The third object of the present application is to propose an electronic device.

[0008] The fourth object of the present application is to propose a computer-readable storage medium.

[0009] The fifth object of the present application is to propose a computer program product.

[0010] To achieve the above object, an embodiment of the first aspect of the present application proposes a geometric recalibration method based on constellation time-series images, including:

[0011] Statistically calculate the long-period included angle change amount between any two star sensors according to the time-series observation vectors of the star sensors, and decompose the long-period included angle change amount into three-axis attitude change angles;

[0012] Perform aberration compensation according to the original data of the star sensors to determine the three-axis attitude correction value;

[0013] Based on the three-axis attitude change angles and the three-axis attitude correction values of the included angle long-period change, determine the three-axis optimized attitude angles;

[0014] Determine a recalibration model based on the three-axis optimized attitude angles, and solve the recalibration model to obtain an optimal calibration model for image calibration.

[0015] To achieve the above object, an embodiment of the second aspect of the present application provides a geometric recalibration device based on star cluster time-series images, including:

[0016] A first acquisition module, configured to statistically calculate the long-period included angle change amount between any two star sensors according to the time-series observation vectors of the star sensors, and decompose the long-period included angle change amount into three-axis attitude change angles;

[0017] A second acquisition module, configured to perform light-time correction based on the original data of the star sensors to determine three-axis attitude correction values;

[0018] A third acquisition module, configured to determine three-axis optimized attitude angles based on the three-axis attitude change angles and the three-axis attitude correction values that vary with the long period of the included angle;

[0019] A calibration model acquisition module, configured to determine a recalibration model based on the three-axis optimized attitude angles, and solve the recalibration model to obtain an optimal calibration model for image calibration.

[0020] To achieve the above object, an embodiment of the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0021] The memory stores computer-executable instructions;

[0022] The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of the embodiments of the first aspect.

[0023] To achieve the above object, an embodiment of the fourth aspect of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of the embodiments of the first aspect.

[0024] To achieve the above object, an embodiment of the fifth aspect of the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the method according to any one of the embodiments of the first aspect.

[0025] The geometric recalibration method, device, and electronic device based on constellation time-series images provided by this application determine the long-period angle change amount, decompose it according to the long-period angle change amount to obtain the three-axis attitude change angles, determine the attitude correction value based on aberration compensation, obtain the three-axis optimized attitude angles according to the attitude correction value and the three-axis attitude change angles. These optimized attitude angles incorporate the compensated and corrected attitude values and the angle change characteristics, construct a more accurate recalibration model, solve this recalibration model to obtain the optimal calibration model for image calibration, solve the problem of the spatial reference change of constellation long time-series images in the prior art, and significantly improve the geometric positioning accuracy compared with traditional methods.

[0026] Additional aspects and advantages of this application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of this application. Brief Description of the Drawings

[0027] The above-mentioned and / or additional aspects and advantages of this application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0028] Figure 1 is a schematic flowchart of a geometric recalibration method based on constellation time-series images provided by an embodiment of this application;

[0029] Figure 2 is a schematic flowchart of another geometric recalibration method based on constellation time-series images provided by an embodiment of this application;

[0030] Figure 3 is a schematic structural diagram of a geometric recalibration device based on constellation time-series images provided by an embodiment of this application. Detailed Description of the Embodiments

[0031] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain this application and should not be construed as limiting this application.

[0032] In the prior art, the on-orbit geometric calibration work of the single-satellite system was carried out immediately after on-orbit operation, and on-orbit geometric calibration was performed regularly to continuously track and analyze the state of the on-satellite payload, aiming to eliminate the external system errors of the satellite platform (such as the deformation of the camera installation angle relative to the laboratory calibration value under the influence of the space mechanical environment during satellite launch) and the internal system errors of the camera (such as the calibration error of the principal point distance and the optical distortion of the objective lens), so as to ensure the geometric quality of the image products.

[0033] The existing calibration model is as follows:

[0034]

[0035] Among them, is the viewing vector of the Charge-Coupled Device (CCD) detector element in the camera coordinate system; is the transformation matrix from the camera coordinate system to the satellite body coordinate system; is the transformation matrix from the satellite body coordinate system to the J2000 inertial coordinate system; is the rotation matrix from the inertial coordinate system to the Earth-Centered Earth-Fixed (ECEF) coordinate system; λ is the proportionality coefficient; is the position of the satellite platform at the imaging moment of ephemeris interpolation; is the geocentric rectangular coordinates of the intersection point of the CCD detector element's line of sight and the Earth ellipsoid; is the eccentric vector from the projection center to the antenna phase center in the satellite body coordinate system.

[0036] With the development of hardware technology, the on-orbit life of satellites is getting longer and longer. It is precisely because satellites operate on orbit for a long time that there are significant differences in the space environment such as temperature, humidity, and air pressure at different times during on-orbit operation. Factors such as the measurement benchmarks of imaging sensors, orbit attitude measurement sensors, etc. with long time intervals and the device loss and aging caused by long-term use will also lead to different imaging parameters for different satellites in the constellation for the sequence images of the same mission area.

[0037] The existing technology only considers the geometric positioning situation of a single satellite at a certain moment, does not consider the geometric positioning situation of the long-time series images of constellation data, nor does it consider the change situation of the space reference. In order to achieve the consistency of the space reference of optical satellite constellation remote sensing images, it is necessary to accurately know various imaging parameters (such as imaging moment, space cold and hot environment, shooting angle, solar altitude angle, star sensor reference switching, long-period low-frequency error, etc.) of the imaging sensor during image acquisition, and perform compensation based on the strict geometric relationship model between traditional optical satellite images and ground targets.

[0038] Due to the combined influence of four types of error sources: camera design, attitude orbit observation, time synchronization, and observed data in processing, the traditional attitude processing and geometric calibration methods cannot meet the geometric positioning accuracy requirements. In view of this, the main purpose of the present invention is to, on the basis of traditional geometric calibration technology, take into account the long and short period laws based on attitude correction processing and the change of the optical axis angle, introduce a long-term time-varying attitude error correction model for compensation, and based on the characteristics of the long-period change law of the corrected attitude and the change of the optical axis angle, establish a low-frequency error time-varying correction model considering the corrected attitude and the change of the optical axis angle, and perform correction and verification through big data analysis to solve the technical problems existing in the prior art.

[0039] The geometric recalibration method, device, and electronic device based on constellation time-series images according to the embodiments of the present application will be described below with reference to the accompanying drawings.

[0040] Figure 1 The following is a schematic flowchart of a geometric recalibration method based on constellation time-series images provided by the embodiments of the present application. As Figure 1 shown, the method includes the following steps:

[0041] S101: According to the time-series observation vectors of star sensors, statistically calculate the long-period angular change amount between any two star sensors, and decompose the long-period angular change amount into three-axis attitude change angles.

[0042] A star sensor is a high-precision attitude-sensitive measurement instrument. Taking the stars as the reference system, it can provide accurate spatial orientation and reference, and has the advantages of high precision, strong anti-interference ability, and independent navigation. Optionally, in this embodiment, the time-series observation vector of the star sensor is the quaternion observation value of the star sensor. The star sensor can directly obtain the quaternion of the satellite in the inertial space, and the quaternion observation value is the key data for describing the attitude and position of the spacecraft in space.

[0043] For star sensor A and star sensor B, their corresponding quaternion observation values at time t are respectively expressed as:

[0044]

[0045] where is the observation vector of star sensor A at time t; is the observation vector of star sensor B at time t; and are respectively the quaternion observation values of star sensor A; and are respectively the quaternion observation values of star sensor B.

[0046] In some implementations, the coordinate representation of the sensitive optical axis (observation direction) corresponding to the star sensor in the inertial coordinate system can be determined according to the observation vector of the star sensor. For example, the coordinate representations of star sensor A and star sensor B in the inertial coordinate system are respectively:

[0047]

[0048] where Z A is the coordinate representation of the sensitive optical axis corresponding to star sensor A in the inertial coordinate system; Z B is the coordinate representation of the sensitive optical axis corresponding to star sensor B in the inertial coordinate system.

[0049] Further, the included angle can be calculated based on the respective coordinate representations of star sensor A and star sensor B. The included angle between star sensor A and star sensor B is expressed as:

[0050]

[0051] Wherein, is the included angle between star sensor A and star sensor B.

[0052] It can be understood that the included angle between star sensor A and star sensor B will vary at different sampling points. The average value of the included angles of the corresponding two star sensors during the satellite shooting period can be used as the long-period included angle value for this recalibration, while the reference included angle is the corresponding satellite design value or the included angle value of the previous calibration. The difference between the long-period included angle value during the shooting period and the reference included angle is used as the current long-period included angle change amount; in some implementations, the sampling points of the star sensors during the shooting period specifically depend on the sampling frequency. For example, when the sampling frequency is 4 Hz, 1 second includes 4 sampling points, and when the sampling frequency is 16 Hz, 1 second includes 16 sampling points.

[0053] In this embodiment, when actually analyzing and obtaining the long-period included angle change amount, the average value of the included angle change amounts of all sampling points during the satellite shooting period can be obtained, and the difference between the average value and the reference included angle value is used as the final long-period included angle change amount. For example, if the satellite shooting period is 2 seconds and the sampling frequency is 4 Hz, the change amount between the average included angle of 8 sampling points within 2 seconds and the reference included angle value is used as the final long-period included angle change amount. Based on this long-period included angle change amount, the attitude change angle is obtained to consider the geometric positioning in the long-time series images of the star cluster data and improve the geometric positioning accuracy.

[0054] Further, after obtaining the long-period included angle change amount of star sensor A and star sensor B, the long-period included angle change amount is decomposed into three-axis attitude change angles. The three-axis attitude angles include yaw angle Yaw, pitch angle Pitch, and roll angle Roll, which respectively describe the rotation angles of an object around the Z-axis, Y-axis, and X-axis of the fixed coordinate system; optionally, the rotation order can be determined. For example, the rotation order follows the Z-Y-X Euler angle system, that is, first rotate around the Z-axis (yaw angle), then rotate around the Y-axis (pitch angle), and finally rotate around the X-axis (roll angle). For this rotation order, the rotation matrix is determined. For the Z-Y-X rotation order, the rotation matrix can be expressed as the product of three basic rotation matrices. The rotation matrix can be calculated through the included angle change amount, and the three-axis attitude change angles, that is, Yaw, Pitch, and Roll, can be inversely deduced according to the rotation matrix. The specific details are not elaborated here.

[0055] S102. Perform aberration compensation based on the original data of the star sensor to determine the three-axis attitude correction value.

[0056] Optionally, the geocentric velocity and satellite velocity at the current moment can be obtained, and the aberration compensation amount at the current moment can be calculated based on the geocentric velocity and satellite velocity at the current moment. The preliminary three-axis attitude values of the star sensor are obtained, and the calculated aberration compensation amount is applied to the preliminary three-axis attitude values for correction to obtain the corrected three-axis attitude correction values, ensuring the high precision and reliability of the star sensor in measurement. The processes of obtaining the geocentric velocity, satellite velocity, and preliminary three-axis attitude values can all adopt conventional means and are not specifically described in this embodiment.

[0057] S103. Determine the three-axis optimized attitude angles based on the three-axis attitude change angles and three-axis attitude correction values with long-period changes in the included angle.

[0058] Optionally, the sums of the attitude change angles and attitude correction values on the corresponding axes can be calculated respectively, and the sum results are used as the optimized attitude angles on the corresponding axes. For example, the sum of the Yaw attitude change angle and the Yaw attitude correction value is the Yaw optimized attitude angle, the sum of the Pitch attitude change angle and the Pitch attitude correction value is the Pitch optimized attitude angle, and the sum of the Roll attitude change angle and the Roll attitude correction value is the Roll optimized attitude angle.

[0059] S104. Determine the recalibration model based on the three-axis optimized attitude angles, and solve the recalibration model to obtain the optimal calibration model for image calibration.

[0060] Optionally, the attitude angles in the existing calibration model can be updated according to the three-axis optimized attitude angles, so as to obtain the recalibration model. That is, the recalibration model in this embodiment can be expressed as:

[0061]

[0062] roll = roll 修正值 + Δroll 变化角

[0063] pitch = pitch 修正值 + Δpitch 变化角

[0064] yaw = yaw 修正值 + Δyaw 变化角

[0065]

[0066] Wherein, is the conversion matrix from the camera coordinate system to the satellite body coordinate system. The roll, pitch, and yaw in this rotation matrix are the optimized attitude angles respectively, that is, the sums of the attitude change angles and attitude correction values on the corresponding axes.

[0067] Further, the calibration parameters in the recalibration model are solved. In this embodiment, the calibration parameters include internal calibration parameters and external calibration parameters. The internal calibration parameters include a0, a1, a2, a3, b0, b1, b2, and b3, which are used to determine the pointing angles of each CCD detector element in the camera coordinate system. The external calibration parameter is used to compensate for the errors of the external orientation elements of the camera and determine the attitude of the camera coordinate system in space. After calculating the calibration parameters in the recalibration model, update the parameters in the recalibration model based on the calculated calibration parameters to obtain an optimal calibration model for image calibration, so as to improve the accuracy of block positioning.

[0068] In this embodiment, the long-period angle change amount is determined through the time-series observation vectors of the star sensors, and the three-axis attitude change angles are decomposed according to the long-period angle change amount. Based on the aberration compensation, the corrected attitude correction value is determined. Based on the corrected attitude correction value and the three-axis attitude change angles, the three-axis optimized attitude angles are obtained. These optimized attitude angles integrate the compensated and corrected attitude values and the angle change characteristics, comprehensively consider the influence of errors, construct a more accurate recalibration model, and solve the recalibration model to obtain the optimal calibration model under the optimal parameters for image calibration, which solves the problem of inconsistency of the spatial reference of optical satellite remote sensing images and significantly improves the geometric positioning accuracy compared with traditional methods.

[0069] Based on the above embodiments, Figure 2 is a schematic flowchart of another geometric recalibration method based on star cluster time-series images provided by the embodiments of the present application. As Figure 2 shown, the method includes the following steps:

[0070] S201, statistically calculate the long-period angle change amount between any two star sensors according to the time-series observation vectors of the star sensors, and decompose the long-period angle change amount into three-axis attitude change angles.

[0071] In some implementations, the coordinate representation of the star sensor in the inertial coordinate system can be determined according to the time-series observation vector of the star sensor at the current moment. In this embodiment, the current moment is the current sampling point. The time-series observation vectors of any star sensor A and star sensor B at time t can be respectively expressed as and The coordinate representation of star sensor A is The corresponding coordinate representation of star sensor B is

[0072] Further, based on the coordinate representations of the star sensors, determine the angle between any two star sensors. In this embodiment, the angle between star sensor A and star sensor B is calculated as

[0073] Further, determine the difference between the included angle and the reference included angle to obtain the included angle change amount, where the included angle is the average value of the included angles of the corresponding two star sensors during the satellite shooting period, and the reference included angle is the corresponding satellite design value or the included angle value of the previous calibration. By way of example, if the currently analyzed sampling frame is the 3rd sampling point, calculate the average value of all the included angles of star sensor A and star sensor B during the satellite shooting period as the long-period included angle, and take the difference between the long-period included angle (average value of the included angles) of star sensor A and star sensor B during the satellite shooting period and the reference included angle as the long-period included angle change amount.

[0074] In the embodiments of the present application, the implementation method of step S201 can be implemented in any one of the embodiments of the present disclosure, and no limitation is made herein and no further elaboration is provided.

[0075] S202. Perform light-time correction based on the original data of the star sensor to determine the three-axis attitude correction value.

[0076] In the embodiments of the present application, the implementation method of step S202 can be implemented in any one of the embodiments of the present disclosure, and no limitation is made herein and no further elaboration is provided.

[0077] S203. Obtain the roll optimized attitude angle according to the summation result of the roll attitude change angle and the roll attitude correction value.

[0078] In this embodiment, the summation result of the roll attitude change angle and the roll attitude correction value is used as the roll optimized attitude angle.

[0079] S204. Obtain the pitch optimized attitude angle according to the summation result of the pitch attitude change angle and the pitch attitude correction value.

[0080] In this embodiment, the summation result of the pitch attitude change angle and the pitch attitude correction value is used as the pitch optimized attitude angle.

[0081] S205. Obtain the yaw optimized attitude angle according to the summation result of the yaw attitude change angle and the yaw attitude correction value.

[0082] In this embodiment, the summation result of the yaw attitude change angle and the yaw attitude correction value is used as the yaw optimized attitude angle.

[0083] S206. Determine the optimized transformation matrix from the camera coordinate system to the satellite body coordinate system based on the three-axis optimized attitude angles.

[0084] Optionally, the optimized transformation matrix can be expressed as:

[0085]

[0086] Among them, roll 修正值 , pitch 修正值 and yaw 修正值 respectively represent the roll attitude correction value, the pitch attitude correction value, and the yaw attitude correction value; Δroll 变化角 , Δpitch 变化角 and Δyaw 变化角 respectively represent the roll attitude change angle, the pitch attitude change angle, and the yaw attitude change angle.

[0087] S207. Obtain the set of model parameters, and determine the recalibration model according to the set of model parameters and the optimized rotation matrix.

[0088] Among them, the set of model parameters includes at least the viewing vector of the charge-coupled device (CCD) detector element in the camera coordinate system, the transformation matrix from the satellite body coordinate system to the J2000 inertial coordinate system, the rotation matrix from the inertial coordinate system to the Earth-Centered Earth-Fixed (ECEF) coordinate system, the satellite platform position, the geocentric rectangular coordinate position of the intersection of the CCD detector element's line of sight and the Earth ellipsoid, and the eccentric vector from the projection center to the antenna phase center in the satellite body coordinate system.

[0089] Optionally, the recalibration model can be expressed as:

[0090]

[0091] Among them, is the viewing vector of the CCD detector element in the camera coordinate system; is the optimized transformation matrix from the camera coordinate system to the satellite body coordinate system, which can also be expressed as the sum of the attitude value and the corrected attitude angle, that is is the transformation matrix from the satellite body coordinate system to the J2000 inertial coordinate system; is the rotation matrix from the inertial coordinate system to the Earth-Centered Earth-Fixed (ECEF) coordinate system; λ is the proportionality coefficient; is the position of the satellite platform at the imaging time interpolated from the ephemeris; is the geocentric rectangular coordinate of the intersection of the CCD detector element's line of sight and the Earth ellipsoid; is the eccentric vector from the projection center to the antenna phase center in the satellite body coordinate system.

[0092] S208. Solve the recalibration model to obtain the optimal calibration model for image calibration.

[0093] Optionally, uniformly distributed high-precision control points can be measured on the image to be calibrated; determine the external calibration parameters and internal calibration parameters in the recalibration model. In this embodiment, let:

[0094]

[0095] Then, based on the derivation, it can be obtained that:

[0096]

[0097] Among them, X E is the external calibration parameter, that is, roll 优化 , pitch 优化 and yaw 优化 , where x1, x2, …, z2 and z3 are constructed based on the sine and cosine values of the optimized attitude angles of the three axes; X I is the internal calibration parameter, specifically 8 parameters a0, a1, …, b2 and b3.

[0098] Furthermore, based on the high-precision control points, the external calibration parameters and internal calibration parameters are solved to obtain the optimal external calibration parameters and optimal internal calibration parameters; according to the optimal external calibration parameters and optimal internal calibration parameters, the parameters in the re-calibration model are updated to determine the optimal calibration model parameters for determining the optimal calibration model.

[0099] In some implementations, the initial values of the external calibration parameters and internal calibration parameters can be determined, and according to the initial values of the internal calibration parameters, the external calibration parameters are iteratively solved for each high-precision control point using the least squares method to determine the first updated external calibration parameters for each iteration; according to the difference between the first updated external calibration parameters of the current iteration and the second updated external calibration parameters of the previous iteration, the external calibration parameter correction amount is determined; in response to the external calibration parameter correction amounts all being less than the first threshold, the first updated external calibration parameters of the current iteration are determined as the optimal external calibration parameters and the iteration is stopped.

[0100] Exemplarily, assuming that the initial value of the external calibration parameter is A1, taking the initial value of the internal calibration parameter as the "true value", the external calibration parameters are solved for each high-precision control point using the least squares method to obtain the current first updated external calibration parameter A2. At this time, the external calibration parameter correction amount is the difference between the current A2 and the previous initial value A1; if the external calibration parameter correction amount is greater than or equal to the first threshold, continue to solve the external calibration parameters for each high-precision control point using the least squares method to obtain the current first updated external calibration parameter A3. At this time, the external calibration parameter correction amount is the difference between the current A3 and the previous A2. If the current external calibration parameter correction amounts are all less than the first threshold, then A3 is determined as the optimal external calibration parameter.

[0101] It can be understood that the first updated external calibration parameter in this embodiment is a parameter value obtained based on the sum of the attitude correction value and the attitude change angle, that is, an optimized attitude value obtained by combining the aberration compensation and integrating the characteristics of the change in the optical axis included angle, which can effectively improve the acquisition accuracy of the external calibration parameter.

[0102] Further, based on a method similar to the above iterative acquisition of the optimal external calibration parameter, the internal calibration parameter can be iteratively solved for each high-precision control point by using the least squares method based on the optimal external calibration parameter, and the first updated internal calibration parameter for each iteration is determined; according to the difference between the first updated internal calibration parameter of the current iteration and the second updated internal calibration parameter of the previous iteration, the internal calibration parameter correction amount is determined; in response to the internal calibration parameter correction amounts all being less than the second threshold, the first updated internal calibration parameter of the current iteration is determined as the optimal internal calibration parameter and the iteration is stopped.

[0103] That is, the optimal external calibration parameter is determined as the true value, the initial value of the internal calibration parameter is denoted as B1, the internal calibration parameter is calculated for each control point by using the least squares method to obtain the current first updated internal calibration parameter B2. At this time, the internal calibration parameter correction amount is the difference between the current B2 and the previous initial value B1. If the internal calibration parameter correction amount is greater than or equal to the second threshold, the internal calibration parameter is continuously calculated for each high-precision control point by using the least squares method to obtain the current first updated internal calibration parameter B3. At this time, the internal calibration parameter correction amount is the difference between the current B3 and the previous B2. If the current internal calibration parameter correction amounts are all less than the second threshold, B3 is determined as the optimal internal calibration parameter.

[0104] It can be understood that after determining the optimal external calibration parameter and the optimal internal calibration parameter, the parameters in the recalibration model are updated based on the optimal external calibration parameter and the optimal internal calibration parameter to obtain the optimal calibration model under the optimal parameters, and image calibration is performed according to this optimal calibration model.

[0105] Further, during the process of image calibration based on the optimal calibration model, the parameters in the optimal calibration model can also be adaptively adjusted based on the included angle change in the actual scene to ensure that the optimal calibration model can best adapt to the calibration scene and improve the calibration analysis accuracy.

[0106] In this embodiment, the long-period angle change amount is determined by the average value of the angle changes between star sensors, and then the three-axis attitude change angles under the comprehensive change are determined according to the long-period angle change amount. The attitude correction value after light-time correction is summed with the attitude change angle under the corresponding axis to obtain the optimized attitude angle of the corresponding axis. The recalibration model is determined according to the three-axis optimized attitude angles, and the optimal external calibration parameters and internal calibration parameters are obtained by solving the recalibration model based on the least squares method. In this embodiment, the external calibration parameters are different from the traditional attitude angles, and the optimal calibration model is determined based on the optimized attitude angles after optimizing the errors, effectively improving the geometric positioning accuracy of the optimal calibration model.

[0107] To implement the above embodiment, the present application also proposes a geometric recalibration device based on star cluster time-series images.

[0108] Figure 3 FIG. is a schematic structural diagram of a geometric recalibration device based on star cluster time-series images provided by an embodiment of the present application.

[0109] As Figure 3 shown, the geometric recalibration device 300 based on star cluster time-series images includes:

[0110] A first acquisition module 301, configured to statistically calculate the long-period angle change amount between any two star sensors according to the time-series observation vectors of the star sensors, and decompose the long-period angle change amount into three-axis attitude change angles;

[0111] A second acquisition module 302, configured to perform light-time correction according to the original data of the star sensors to determine the three-axis attitude correction values;

[0112] A third acquisition module 303, configured to determine the three-axis optimized attitude angles based on the three-axis attitude change angles and the three-axis attitude correction values of the long-period angle change;

[0113] A calibration model acquisition module 304, configured to determine a recalibration model according to the three-axis optimized attitude angles, and solve the recalibration model to obtain an optimal calibration model for image calibration.

[0114] Further, in a possible implementation manner of the embodiment of the present application, the first acquisition module 301 includes:

[0115] Determine the coordinate representation of the star sensor in the inertial coordinate system according to the time-series observation vector of the star sensor at the current moment;

[0116] Based on the coordinate representation of the star sensor, determine the angle between any two star sensors, and determine the long-period angle between the two star sensors according to the average value of all angles between the corresponding two star sensors during the satellite shooting period;

[0117] Determine the difference between the long-period angle and the reference angle to obtain the long-period angle change amount, where the reference angle is the corresponding satellite design value or the angle value of the previous calibration.

[0118] Further, in a possible implementation manner of the embodiment of the present application, the third acquisition module 303 includes:

[0119] Obtain the roll optimized attitude angle according to the summation result of the roll attitude change angle and the roll attitude correction value;

[0120] Obtain the pitch optimized attitude angle according to the summation result of the pitch attitude change angle and the pitch attitude correction value;

[0121] Obtain the yaw optimized attitude angle according to the summation result of the yaw attitude change angle and the yaw attitude correction value.

[0122] Further, in a possible implementation manner of the embodiment of the present application, the calibration model acquisition module 304 includes:

[0123] Determine the optimized transformation matrix from the camera coordinate system to the satellite body coordinate system based on the three-axis optimized attitude angle;

[0124] Obtain the model parameter set, and determine the recalibration model according to the model parameter set and the optimized rotation matrix; where the model parameter set at least includes the viewing vector of the charge-coupled device (CCD) detector element in the camera coordinate system, the transformation matrix from the satellite body coordinate system to the J2000 inertial coordinate system, the rotation matrix from the inertial coordinate system to the Earth-centered Earth-fixed (ECEF) coordinate system, the satellite platform position, the geocentric rectangular coordinate position of the intersection of the CCD detector element's line of sight and the Earth ellipsoid, and the eccentric vector from the projection center to the antenna phase center in the satellite body coordinate system.

[0125] Further, in a possible implementation manner of the embodiment of the present application, the calibration model acquisition module 304 includes:

[0126] Measure uniformly distributed high-precision control points on the image to be calibrated;

[0127] Determine the external calibration parameters and internal calibration parameters in the recalibration model, and solve the external calibration parameters and internal calibration parameters based on the high-precision control points to obtain the optimal external calibration parameters and optimal internal calibration parameters;

[0128] Update the parameters in the recalibration model according to the optimal external calibration parameters and optimal internal calibration parameters to determine the optimal calibration model parameters for determining the optimal calibration model.

[0129] Further, in a possible implementation manner of the embodiment of the present application, the calibration model acquisition module 304 includes:

[0130] Determine the initial values of the external calibration parameters and the internal calibration parameters, and based on the initial values of the internal calibration parameters, use the least squares method to iteratively solve the external calibration parameters for each high-precision control point to determine the first updated external calibration parameters for each iteration.

[0131] Determine the external calibration parameter correction amount according to the difference between the first updated external calibration parameters of the current iteration and the second updated external calibration parameters of the previous iteration.

[0132] In response to the external calibration parameter correction amounts all being less than the first threshold, determine the first updated external calibration parameters of the current iteration as the optimal external calibration parameters and stop the iteration.

[0133] Furthermore, in a possible implementation manner of the embodiment of the present application, the calibration model acquisition module 304 includes:

[0134] Based on the optimal external calibration parameters, use the least squares method to iteratively solve the internal calibration parameters for each high-precision control point to determine the first updated internal calibration parameters for each iteration.

[0135] Determine the internal calibration parameter correction amount according to the difference between the first updated internal calibration parameters of the current iteration and the second updated internal calibration parameters of the previous iteration.

[0136] In response to the internal calibration parameter correction amounts all being less than the second threshold, determine the first updated internal calibration parameters of the current iteration as the optimal internal calibration parameters and stop the iteration.

[0137] It should be noted that the foregoing explanation of the embodiment of the geometric recalibration method based on constellation time-series images also applies to the geometric recalibration device based on constellation time-series images of this embodiment, and will not be elaborated here.

[0138] In the embodiment of the present application, the long-period angle change amount is determined by the average value of the angle changes between star sensors, and then the triaxial attitude change angles under the comprehensive change are determined according to the long-period angle change amount. The attitude correction value after light travel time compensation is summed with the attitude change angle under the corresponding axis to obtain the optimized attitude angle of the corresponding axis; the recalibration model is determined according to the triaxial optimized attitude angles, and the recalibration model is solved based on the least squares method to obtain the optimal external calibration parameters and internal calibration parameters. Moreover, the external calibration parameters in this embodiment are different from the traditional attitude angles, and the optimal calibration model is determined based on the optimized attitude angles after optimizing the errors, effectively improving the geometric positioning accuracy of the optimal calibration model.

[0139] To implement the above embodiment, the present application also proposes an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiment.

[0140] To implement the above embodiments, the present application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0141] To implement the above embodiments, the present application also provides a computer program product including a computer program, which, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0142] The collection, storage, use, processing, transmission, provision, and disclosure of the user's personal information involved in the present application all comply with the provisions of relevant laws and regulations and do not violate public order and good customs.

[0143] It should be noted that personal information from users should be collected for legal and reasonable purposes and not shared or sold outside of such legal uses. In addition, such collection / sharing should be carried out after obtaining the informed consent of the user, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization including authorizing relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others with access to the personal information data comply with their privacy policies and procedures.

[0144] The present application anticipates providing embodiments that allow users to selectively block the use or access of personal information data. That is, the present disclosure anticipates providing hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, the risk can be minimized by restricting data collection and deleting the data. In addition, when applicable, personal identifiers are removed from such personal information to protect the privacy of the user.

[0145] In the description of the foregoing embodiments, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0146] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0147] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logical function or process. The scope of the preferred embodiments of this application includes additional implementations, where functions may be performed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the technical field to which the embodiments of this application pertain.

[0148] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with such instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0149] It should be understood that each part of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following techniques known in the art or a combination thereof can be used: discrete logic circuits with logic gate circuits for implementing logic functions on data signals, application specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0150] Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program. The said program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0151] In addition, each functional unit in various embodiments of the present application can be integrated in a processing module, or each unit can exist physically alone, or two or more units can be integrated in a module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the above integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0152] The above-mentioned storage medium can be a read-only memory, a magnetic disk, an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A geometric recalibration method based on constellation time-series images, characterized in that Including: Statistically analyze the long-period angular change between any two star sensors based on the timing observation vectors of the star sensors, and decompose the long-period angular change into three-axis attitude change angles; Perform light-time correction based on the original data of the star sensors to determine three-axis attitude correction values; Determine three-axis optimized attitude angles based on the three-axis attitude change angles and the three-axis attitude correction values due to the long-period angular change; Determine a recalibration model based on the three-axis optimized attitude angles, and solve the recalibration model to obtain an optimal calibration model for image calibration.

2. The method according to claim 1, wherein The step of statistically analyzing the long-period angular change between any two star sensors based on the timing observation vectors of the star sensors includes: Determine the coordinate representation of the star sensor in the inertial coordinate system based on the timing observation vector of the star sensor at the current moment; Based on the coordinate representation of the star sensor, determine the angle between any two star sensors, and determine the long-period angle between the two star sensors according to the average value of all angles between the corresponding two star sensors during the satellite shooting period; Determine the difference between the long-period angle and the reference angle to obtain the long-period angular change, where the reference angle is the corresponding satellite design value or the angle value of the previous calibration.

3. The method according to claim 1 or 2, characterized in that, The step of determining three-axis optimized attitude angles based on the three-axis attitude change angles and the three-axis attitude correction values due to the long-period angular change includes: Obtain the optimized roll attitude angle according to the sum of the roll attitude change angle and the roll attitude correction value; Obtain the optimized pitch attitude angle according to the sum of the pitch attitude change angle and the pitch attitude correction value; Obtain the optimized yaw attitude angle according to the sum of the yaw attitude change angle and the yaw attitude correction value.

4. The method according to claim 3, characterized in that, The step of determining a recalibration model based on the three-axis optimized attitude angles includes: Determine an optimized transformation matrix from the camera coordinate system to the satellite body coordinate system based on the three-axis optimized attitude angles; Obtain a set of model parameters, and determine a recalibration model according to the set of model parameters and the optimized rotation matrix; where the set of model parameters at least includes the view vector of the charge-coupled device (CCD) detector element in the camera coordinate system, the transformation matrix from the satellite body coordinate system to the J2000 inertial coordinate system, the rotation matrix from the inertial coordinate system to the Earth-centered, Earth-fixed (ECEF) coordinate system, the satellite platform position, the geocentric rectangular coordinate position of the intersection of the CCD detector element's line of sight and the Earth ellipsoid, and the eccentricity vector from the projection center to the antenna phase center in the satellite body coordinate system.

5. The method according to claim 4, characterized in that, The step of solving the recalibration model to obtain optimal calibration model parameters includes: Measure uniformly distributed high-precision control points on the image to be calibrated; Determine the external calibration parameters and internal calibration parameters in the recalibration model, and solve the external calibration parameters and the internal calibration parameters based on the high-precision control points to obtain the optimal external calibration parameters and the optimal internal calibration parameters; Update the parameters in the recalibration model according to the optimal external calibration parameters and the optimal internal calibration parameters to determine the optimal calibration model parameters for determining the optimal calibration model.

6. The method according to claim 5, wherein The method for obtaining the optimal external calibration parameters includes: Determine the initial values of the external calibration parameters and the internal calibration parameters, and based on the initial values of the internal calibration parameters, use the least squares method to iteratively solve the external calibration parameters for each of the high-precision control points to determine the first updated external calibration parameters for each iteration; Determine the external calibration parameter correction amount based on the difference between the first updated external calibration parameters of the current iteration and the second updated external calibration parameters of the previous iteration; In response to the external calibration parameter correction amounts all being less than the first threshold, determine the first updated external calibration parameters of the current iteration as the optimal external calibration parameters and stop the iteration.

7. The method according to claim 6, wherein The method for obtaining the optimal internal calibration parameters includes: Based on the optimal external calibration parameters, use the least squares method to iteratively solve the internal calibration parameters for each of the high-precision control points to determine the first updated internal calibration parameters for each iteration; Determine the internal calibration parameter correction amount based on the difference between the first updated internal calibration parameters of the current iteration and the second updated internal calibration parameters of the previous iteration; In response to the internal calibration parameter correction amounts all being less than the second threshold, determine the first updated internal calibration parameters of the current iteration as the optimal internal calibration parameters and stop the iteration.

8. A geometric recalibration device based on constellation time-series images, characterized in that, It includes: A first acquisition module, configured to statistically calculate the long-period included angle change amount between any two star sensors according to the time-series observation vectors of the star sensors, and decompose the long-period included angle change amount into three-axis attitude change angles; A second acquisition module, configured to perform light travel time compensation according to the original data of the star sensors to determine the three-axis attitude correction value; A third acquisition module, configured to determine the three-axis optimized attitude angles based on the three-axis attitude change angles and the three-axis attitude correction values of the long-period included angle change; A calibration model acquisition module, configured to determine a recalibration model according to the three-axis optimized attitude angles, and solve the recalibration model to obtain an optimal calibration model for image calibration.

9. An electronic device, characterized in that, It includes: A processor and a memory communicatively connected to the processor; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, Computer execution instructions are stored in the computer-readable storage medium, and when the computer execution instructions are executed by the processor, they are used to implement the method according to any one of claims 1-7.

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