Method and system for resolving positioning deviation of long linear array load of stationary meteorological satellite

Abstract

The invention provides a stationary meteorological satellite long linear array load positioning deviation resolving method and system, positioning deviation resolving of a full observation area is achieved through a small number of geometric scaling points, and the method comprises the steps that a long linear array load positioning deviation resolving model is deduced according to the imaging principle of a long linear array load; considering the time-varying property of in-orbit deformation, and introducing a positioning deviation resolving model containing time variation; constructing a long linear array load positioning deviation resolving model; designing a positioning deviation calculation precision evaluation method; and designing a positioning deviation calculation precision improvement method considering geometric calibration point precision. According to the method, the working characteristics of the load are fully considered, and the positioning deviation calculation precision can be remarkably improved; the actual working state of the load can be reflected more accurately by constructing the positioning deviation resolving model considering the spatial dimension change caused by the load optical axis direction and the long linear array detector distribution, so that the resolving precision of the positioning deviation is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite overall design and image positioning and registration, and in particular to a method and system for solving positioning deviations of a long linear array payload of a geostationary meteorological satellite. Background Art

[0002] Image positioning is a key metric for geostationary remote sensing satellites, characterizing the accuracy of the observed target or image geometric information. Long linear array payloads achieve coverage of the observation area by driving a dual-mirror, dual-axis scanning imaging system. Due to their large width, long linear array payloads can significantly improve Earth observation efficiency, making them a key payload for meteorological satellites. However, given the complex on-orbit thermal environment of geostationary satellites, the satellite's illuminated surface changes with orbital position, causing complex structural deformation within the satellite platform and remote sensing instruments, leading to deviations in the payload's optical axis pointing and, consequently, positioning errors. Traditional methods for resolving positioning errors use landmarks or stars as reference points to directly identify the payload's optical axis pointing error. However, due to the imaging characteristics of long linear array payloads, the array and payload are dually coupled, resulting in different positioning errors corresponding to different payload pointing areas. Therefore, it is necessary to conduct research on long linear array payload positioning error resolution methods tailored to the payload's imaging method. This approach, using a small number of geometric calibration points, can resolve positioning errors for the entire observation area.

[0003] After literature research, in the paper "On-orbit Temperature Analysis and Thermal Design Optimization of the Gaofen-4 Satellite Camera" (Journal of Beijing University of Aeronautics and Astronautics, Vol. 47, No. 1, 2021), in view of the difficulties and characteristics of the thermal design of the Gaofen-4 satellite camera, based on the design concept of integrated structural thermal control, thermal control technologies such as heat flux shielding at the light entrance, indirect radiation temperature control, and heat dissipation surface coupling were adopted to achieve high-precision temperature control of the camera. The temperature data and compliance of the camera in orbit for 4 years were analyzed, the correctness of the camera's thermal design was verified, and thermal design optimization suggestions were put forward based on the on-orbit operation conditions, providing support for further improving the temperature control accuracy of the geostationary orbit camera and reducing thermal control resources. However, the paper did not involve the relevant content of the positioning deviation solution method.

[0004] The paper "Geopositioning and Bias Correction of the HY-2B Satellite Microwave Radiometer" (Journal of Marine Meteorology, Vol. 42, No. 4, 2022) describes the operating principle of the HY-2B satellite microwave radiometer, satellite ephemeris acquisition, antenna beam pointing calculation, and a series of coordinate system transformation methods. Based on the conical scanning operation of the microwave radiometer, an applicable geopositioning algorithm is proposed and positioning calculations are performed. By correcting relevant parameters, geopositioning bias is corrected. However, the paper does not discuss the relevant content of the positioning bias solution method.

[0005] In the paper “Research on GEO Satellite Image Positioning and Registration Technology and Simulation Verification” (Spacecraft Engineering, Issue 4, 2015), the basic principles of image positioning and registration were introduced, a mathematical model of compensation was established, and a real-time simulation system was used to replace the payload scanning radiometer, atmospheric vertical sounder, attitude and orbit control and other related subsystems to simulate the satellite's on-orbit working conditions. The image positioning and registration technology was simulated and verified, but the relevant content of the positioning deviation solution method was not involved.

[0006] The paper "Preliminary Evaluation of the Uncontrolled Positioning Accuracy of the Gaofen-14 Stereo Mapping Satellite" (Acta Geodaetica et Cartographica Sinica, Vol. 52, No. 1, 2023) focuses on the Gaofen-14 satellite payload and ground mapping processing system, as well as their performance. The paper also conducts a geometric performance evaluation using high-precision test fields at home and abroad. However, the paper does not address positioning bias correction.

[0007] The paper "A Brief Analysis of the Positioning Accuracy of the Tianhui-2 Satellite System" (Acta Geodaetica et Cartographica Sinica, Vol. 51, No. 12, 2022) provides a preliminary exploration of its positioning accuracy. Based on the INSAR mechanism model, the paper analyzes the sources of error affecting positioning accuracy, designs an INSAR data processing pipeline, and utilizes baseline measurement accuracy and ground processing accuracy indicators designed on the ground and measured on-orbit to conduct preliminary on-orbit testing and verification of satellite positioning accuracy in plain and mountainous areas. However, the paper does not address the topic of positioning bias correction.

[0008] In the patent "Method for Extracting Star Center of Mass for Linear Instruments of Geostationary Earth Observation Satellites" (201711002322.X), a method for extracting star center of mass for linear instruments of geostationary Earth observation satellites is disclosed. This patent is mainly aimed at extracting star targets from multi-column short linear array payloads. The disclosed method is to eliminate high-frequency errors in star point positions caused by factors such as detector optical imaging, circuit noise, and satellite high-frequency jitter through multi-column data information fusion processing and curve fitting, thereby improving the recognition accuracy of star position parameters. The core idea of the above patent is to introduce an image processing method for geometric calibration of long linear array payloads, and does not involve a specific positioning deviation solution method.

[0009] Therefore, it is necessary to propose a new technical solution. Summary of the Invention

[0010] In view of the defects in the prior art, the purpose of the present invention is to provide a method and system for solving the positioning deviation of a long linear array payload of a geostationary meteorological satellite.

[0011] According to the present invention, a method for calculating positioning deviation of a long linear array payload of a geostationary meteorological satellite is provided, the method comprising the following steps:

[0012] Step S1: Based on the imaging principle of the long linear array payload, a positioning deviation calculation model is derived and constructed that takes into account the spatial dimensional changes caused by the payload optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors;

[0013] Step S2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method.

[0014] Step S3: constructing a long linear array load positioning deviation solution model, wherein the long linear array load positioning deviation solution model is used to process input information of positioning deviation, wherein the input information includes time, positioning deviation, pointing angle, and pixel number of geometric control point, and solve the positioning deviation according to the input information;

[0015] Step S4: constructing a positioning deviation solution accuracy evaluation method, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy;

[0016] Step S5: Design a method for improving the accuracy of positioning deviation solution that takes into account the accuracy of geometric calibration points, including after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, then determine whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, eliminate the geometric calibration result with the largest solution deviation and re-solve the positioning deviation for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

[0017] Preferably, in step S1, the long linear array load positioning deviation solution model also considers the positioning deviation linearly related to the load two-dimensional scanning mechanism angle, the positioning deviation related to the quadratic term of the load two-dimensional scanning mechanism angle, and the positioning deviation related to the long linear array. The established relationship between the positioning deviation and the spatial dimension is as follows:

[0018] Δew=a1+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0019] Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0020] In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload;

[0021] Parameters a1 and b1 represent the basic deviation of load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the angle of the load's two-dimensional scanning mechanism; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction.

[0022] Preferably, in step S2, when using the positioning deviation solution model that includes time changes, it is necessary to consider the influence of satellite thermal deformation at different times on the positioning deviation, and solve the equivalent parameters through multiple geometric calibration data. The specific expression is as follows:

[0023]

[0024] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0025] Preferably, step S3 includes the following steps:

[0026] Step S3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point;

[0027] Step S3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. A larger Δn indicates a wider distribution of the control points on the long linear array detector, which is more conducive to solving the rotational deformation parameters of the long linear array detector.

[0028] Step S3.3: If Δn is greater than the long-line array positioning deviation calculation threshold, the positioning deviation calculation model including time variation in step S2 is used for calculation;

[0029] Step S3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution method is adopted.

[0030] Preferably, the step S4 includes the following steps:

[0031] Step S4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters;

[0032] Step S4.2: Evaluate the accuracy of the positioning deviation solution by subtracting the actual positioning deviation from the theoretical positioning deviation.

[0033] Preferably, the step S5 includes the following steps:

[0034] Step S5.1: Complete the positioning deviation solution accuracy assessment according to step S4. If all solution errors are less than the error threshold, it means that the solution is normal and the result is directly output; otherwise, the next step needs to be processed;

[0035] Step S5.2: Determine whether the number of geometric calibrations for this group is greater than a threshold. If not, the solution fails and the result is discarded. Otherwise, proceed to the next step.

[0036] Step S5.3: Eliminate the geometric calibration result with the largest solution deviation, recalculate the positioning deviation for the remaining geometric calibration data, and repeat steps S5.1 and S5.2.

[0037] The present invention also provides a system for calculating positioning deviation of a long linear array payload of a geostationary meteorological satellite, the system comprising the following modules:

[0038] Module M1: Based on the imaging principle of the long linear array payload, derive and construct a positioning deviation calculation model that takes into account the spatial dimensional changes caused by the payload optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors;

[0039] Module M2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method.

[0040] Module M3: Constructing a long-line array payload positioning deviation calculation model, which is used to process input information of positioning deviation, including time, positioning deviation, pointing angle, and pixel number of geometric control points, and calculate the positioning deviation based on the input information;

[0041] Module M4: Constructing a positioning deviation solution accuracy evaluation system, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy;

[0042] Module M5: Design a positioning deviation solution accuracy improvement system that takes into account the accuracy of geometric calibration points. This includes, after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, determining whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, the geometric calibration result with the largest solution deviation is eliminated, and the positioning deviation solution is recalculated for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

[0043] Preferably, in module M1, the long linear array load positioning deviation solution model also considers the positioning deviation linearly related to the load two-dimensional scanning mechanism angle, the positioning deviation related to the quadratic term of the load two-dimensional scanning mechanism angle, and the positioning deviation related to the long linear array. The established relationship between the positioning deviation and the spatial dimension is as follows:

[0044] Δew=a1+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0045] Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0046] In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload;

[0047] Parameters a1 and b1 represent the basic deviation of the load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the load's two-dimensional scanning mechanism angle; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction;

[0048] In module M2, when using the positioning deviation solution model that includes time changes, it is necessary to consider the impact of satellite thermal deformation on positioning deviation at different times, and solve the equivalent parameters through multiple geometric calibration data. The specific expression is as follows:

[0049]

[0050] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0051] Preferably, the module M3 includes the following modules:

[0052] Module M3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point;

[0053] Module M3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. The larger Δn is, the wider the distribution of the control points on the long linear array detector is, and the more conducive it is to solving the rotation deformation parameters of the long linear array detector.

[0054] Module M3.3: If Δn is greater than the long-line array positioning deviation solution threshold, the positioning deviation solution model containing time variation in module M2 is used for solution.

[0055] Module M3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution system is used;

[0056] The module M4 includes the following modules:

[0057] Module M4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters;

[0058] Module M4.2: Evaluate the accuracy of positioning deviation calculation by subtracting the actual positioning deviation from the theoretical positioning deviation.

[0059] Preferably, the module M5 includes the following modules:

[0060] Module M5.1: Complete the positioning deviation solution accuracy assessment based on module M4. If all solution errors are less than the error threshold, it means that the solution is normal and the results are output directly; otherwise, the next step is required.

[0061] Module M5.2: Determine whether the number of geometric calibrations of this group involved in the solution is greater than the threshold. If not, it means that the solution has failed and the solution result is discarded. Otherwise, the next step is required.

[0062] Module M5.3: Eliminate the geometric calibration results with the largest solution deviation, recalculate the positioning deviation of the remaining geometric calibration data, and repeatedly call modules M5.1 and M5.2.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] 1. By constructing a positioning deviation calculation model that takes into account the spatial dimensional changes caused by the payload's optical axis orientation and the distribution of long linear array detectors, the present invention can more accurately reflect the actual working state of the payload, thereby significantly improving the accuracy of positioning deviation calculation;

[0065] 2. The present invention introduces a positioning deviation solution model that includes time variation; reflecting the time-varying deformation of the load on track, making the solution result closer to the actual situation and improving the applicability and accuracy of the positioning deviation solution;

[0066] 3. The present invention can monitor and optimize the solution accuracy in real time during the solution process; once the solution error is found to exceed the threshold, the solution accuracy can be quickly improved by eliminating the geometric calibration result with the largest deviation and re-solving; thereby improving the solution efficiency and enhancing the robustness of the entire solution process. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0068] Figure 1 Flowchart for calculating positioning deviation of long linear array payload of geostationary meteorological satellite;

[0069] Figure 2This is a schematic diagram of the two-dimensional pointing direction of the long linear array payload for earth observation;

[0070] Figure 3 This is a schematic diagram of the tilt deformation of the long linear array load detector;

[0071] Figure 4 Positioning deviation handling process for long linear array loads;

[0072] Figure 5 A method to improve the accuracy of long linear array load positioning deviation solution. DETAILED DESCRIPTION

[0073] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0074] Example 1:

[0075] Reference Figure 1 and Figure 2 According to the present invention, a method for calculating the positioning deviation of a long linear array payload of a geostationary meteorological satellite is provided, the method comprising the following steps:

[0076] Step S1: Based on the imaging principle of a long linear array payload, a positioning deviation calculation model is derived and constructed that takes into account the spatial dimensional changes caused by the payload optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors. The long linear array payload positioning deviation calculation model also takes into account the positioning deviation linearly related to the angle of the payload's two-dimensional scanning mechanism, the positioning deviation related to the quadratic term of the angle of the payload's two-dimensional scanning mechanism, and the positioning deviation related to the long linear array. The established relationship between the positioning deviation and the spatial dimension is as follows:

[0077] Δew=a1+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0078] Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0079] In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload;

[0080] Parameters a1 and b1 represent the basic deviation of load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the angle of the load's two-dimensional scanning mechanism; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction.

[0081] Step S2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method. When using the positioning deviation calculation model that includes time variations, the influence of satellite thermal deformation at different times on the positioning deviation must be considered, and the equivalent parameters are solved using multiple geometric calibration data. The specific expressions are as follows:

[0082]

[0083] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0084] Step S3: constructing a long linear array load positioning deviation solution model, wherein the long linear array load positioning deviation solution model is used to process input information of positioning deviation, wherein the input information includes time, positioning deviation, pointing angle, and pixel number of geometric control point, and solve the positioning deviation according to the input information;

[0085] Step S3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point;

[0086] Step S3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. A larger Δn indicates a wider distribution of the control points on the long linear array detector, which is more conducive to solving the rotational deformation parameters of the long linear array detector.

[0087] Step S3.3: If Δn is greater than the long-line array positioning deviation calculation threshold, the positioning deviation calculation model including time variation in step S2 is used for calculation;

[0088] Step S3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution method is adopted.

[0089] Step S4: constructing a positioning deviation solution accuracy evaluation method, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy;

[0090] Step S4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters;

[0091] Step S4.2: Evaluate the accuracy of the positioning deviation calculation by subtracting the actual positioning deviation from the theoretical positioning deviation.

[0092] Step S5: Design a method for improving the accuracy of positioning deviation solution that takes into account the accuracy of geometric calibration points, including after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, then determine whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, eliminate the geometric calibration result with the largest solution deviation and re-solve the positioning deviation for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

[0093] Step S5.1: Complete the positioning deviation solution accuracy assessment according to step S4. If all solution errors are less than the error threshold, it means that the solution is normal and the result is directly output; otherwise, the next step needs to be processed;

[0094] Step S5.2: Determine whether the number of geometric calibrations for this group is greater than a threshold. If not, the solution fails and the result is discarded. Otherwise, proceed to the next step.

[0095] Step S5.3: Eliminate the geometric calibration result with the largest solution deviation, recalculate the positioning deviation for the remaining geometric calibration data, and repeat steps S5.1 and S5.2.

[0096] The present invention also provides a geostationary meteorological satellite long linear array payload positioning deviation solution system. The geostationary meteorological satellite long linear array payload positioning deviation solution system can be implemented by executing the process steps of the geostationary meteorological satellite long linear array payload positioning deviation solution method. That is, those skilled in the art can understand the geostationary meteorological satellite long linear array payload positioning deviation solution method as a preferred implementation of the geostationary meteorological satellite long linear array payload positioning deviation solution system.

[0097] Example 2:

[0098] The present invention also provides a system for calculating positioning deviation of a long linear array payload of a geostationary meteorological satellite, the system comprising the following modules:

[0099] Module M1: Based on the imaging principle of a long linear array payload, a positioning deviation calculation model is derived and constructed that takes into account the spatial dimensional changes caused by the payload's optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors. This long linear array payload positioning deviation calculation model also considers the positioning deviation linearly related to the angle of the payload's two-dimensional scanning mechanism, the positioning deviation related to the quadratic term of the payload's two-dimensional scanning mechanism angle, and the positioning deviation related to the long linear array. The established relationship between positioning deviation and spatial dimension is as follows:

[0100] Δew=a1+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0101] Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0102] In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload;

[0103] Parameters a1 and b1 represent the basic deviation of the load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the load's two-dimensional scanning mechanism angle; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction;

[0104] Module M2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method. When using the positioning deviation calculation model that includes time variations, the impact of satellite thermal deformation at different times on the positioning deviation must be considered, and the equivalent parameters are solved using multiple geometric calibration data. The specific expressions are as follows:

[0105]

[0106] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0107] Module M3: Constructing a long-line array payload positioning deviation calculation model, which is used to process input information of positioning deviation, including time, positioning deviation, pointing angle, and pixel number of geometric control points, and calculate the positioning deviation based on the input information;

[0108] Module M3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point;

[0109] Module M3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. The larger Δn is, the wider the distribution of the control points on the long linear array detector is, and the more conducive it is to solving the rotation deformation parameters of the long linear array detector.

[0110] Module M3.3: If Δn is greater than the long-line array positioning deviation solution threshold, the positioning deviation solution model containing time variation in module M2 is used for solution.

[0111] Module M3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution system is used;

[0112] Module M4: Constructing a positioning deviation solution accuracy evaluation system, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy;

[0113] Module M4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters;

[0114] Module M4.2: Evaluate the accuracy of positioning deviation calculation by subtracting the actual positioning deviation from the theoretical positioning deviation.

[0115] Module M5: Design a positioning deviation solution accuracy improvement system that takes into account the accuracy of geometric calibration points. This includes, after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, determining whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, the geometric calibration result with the largest solution deviation is eliminated, and the positioning deviation solution is recalculated for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

[0116] Module M5.1: Complete the positioning deviation solution accuracy assessment based on module M4. If all solution errors are less than the error threshold, it means that the solution is normal and the results are output directly; otherwise, the next step is required.

[0117] Module M5.2: Determine whether the number of geometric calibrations of this group involved in the solution is greater than the threshold. If not, it means that the solution has failed and the solution result is discarded. Otherwise, the next step is required.

[0118] Module M5.3: Eliminate the geometric calibration results with the largest solution deviation, recalculate the positioning deviation of the remaining geometric calibration data, and repeatedly call modules M5.1 and M5.2.

[0119] Example 3:

[0120] Image positioning is a key metric for geostationary remote sensing satellites, characterizing the accuracy of the observed target or image geometry. Long linear array payloads achieve coverage of the observation area by driving a dual-mirror, dual-axis scanning imaging system. Due to their large width, long linear array payloads significantly improve Earth observation efficiency, making them a crucial payload for meteorological satellites. However, given the complex on-orbit thermal environment of geostationary satellites, the illuminated surface of the satellite changes with orbital position, causing complex structural deformation within the satellite platform and remote sensing instruments, leading to deviations in the payload's optical axis pointing direction and, consequently, positioning errors. The traditional positioning deviation solution method is to use landmarks or stars as reference points to directly identify the optical axis pointing deviation of the payload. However, due to the characteristics of long-line array payload imaging, the array and the payload are doubly coupled, resulting in different positioning deviations corresponding to different areas of the payload pointing. Therefore, a positioning deviation solution method for long-line array payloads of geostationary meteorological satellites is proposed based on the imaging mode of the payload. Through a small number of geometric calibration points, the positioning deviation solution of the entire observation area is achieved. The main contents include the following: (1) According to the imaging principle of the long-line array payload, the positioning deviation solution model of the long-line array payload is derived; (2) Considering the time-varying deformation on orbit, a positioning deviation solution model including time variation is introduced; (3) The positioning deviation solution model of the long-line array payload is constructed; (4) A positioning deviation solution accuracy evaluation method is designed; (5) A positioning deviation solution accuracy improvement method considering the accuracy of geometric calibration points is designed. The positioning deviation solution method for long-line array payloads of geostationary meteorological satellites proposed in this invention fully considers the working characteristics of the payload and can significantly improve the positioning deviation solution accuracy. The method for calculating the positioning deviation of a long linear array payload of a geostationary meteorological satellite proposed in the present invention can effectively solve the problem of positioning deviation of a long linear array payload.

[0121] The specific implementation of the present invention is as follows:

[0122] 1) Establish a model for calculating the positioning deviation of long-array loads

[0123] According to the imaging principle of the long linear array payload of the geostationary meteorological satellite, its instantaneous observation field on the earth is distributed in the north-south direction. Figure 2 .

[0124] To achieve full Earth observation, the long linear array payload's two-dimensional scanning mechanism must be used to adjust the orientation of the payload's optical axis. Based on the long linear array payload's geometric imaging model, the positioning error of the long linear array payload is related to the pointing angle of the two-dimensional scanning mechanism, influenced by deformation within the payload and the satellite platform. This means that the positioning error corresponding to different positions of the long linear array payload's optical axis is inconsistent, and the relationship is not a simple linear one. Furthermore, given the north-south distribution of the long linear array payload's detectors, the positioning error caused by rotational deformation of the detectors is primarily reflected in the east-west direction. Furthermore, this positioning error is related to the long linear array pixel number, and the positioning error corresponding to different pixels is also inconsistent.

[0125] Therefore, when modeling the positioning deviation of a long linear array payload, not only the spatial dimension changes caused by the orientation of the payload optical axis but also the spatial dimension changes caused by the distribution of the long linear array detectors should be considered. Figure 3 , the relationship between the established positioning deviation and the spatial dimension is as follows:

[0126] Δew=a1+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0127] Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0128] In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the long linear array payload's two-dimensional scanning mechanism, and ns represents the east-west pointing angle of the long linear array payload's two-dimensional scanning mechanism. a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation. n represents the long linear array pixel number, and τ represents the pixel angular resolution of the long linear array payload.

[0129] Based on the above analysis, it can be seen that parameters a1 and b1 represent the basic deviation of load positioning; parameters a4, a5, b2, and b3 represent positioning deviations that are linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent positioning deviations related to the quadratic term of the angle of the load's two-dimensional scanning mechanism; and parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction.

[0130] After the satellite enters orbit, the current positioning deviations Δew and Δns can be accurately identified through geometric calibration, and the long linear array detector pixel numbers corresponding to the current payload 2D scanning mechanism angle and geometric control points are recorded. According to the above positioning deviation model, it is necessary to observe the geometric control points at different spatial positions and solve the equivalent parameters using the least squares method. The specific expression is as follows:

[0131]

[0132] In the above formula, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified for the nth geometric calibration. n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n nThe pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration.

[0133] a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, while b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation. By constructing the above linear equations and performing a least squares solution using multiple geometric calibration data, the equivalent parameters of the positioning deviation can be solved, thus forming the long-line array load positioning deviation calculation model.

[0134] 2) Build a positioning deviation solution model that includes time changes

[0135] Satellites and payloads are affected by the space environment while in orbit, and positioning errors vary over time. Time differences exist during on-orbit geometric calibration, and using multiple geometric calibration data for least squares calculations without considering time variations can introduce errors. Therefore, a positioning error calculation model that incorporates time variations was constructed:

[0136] Δew=a1+k a t+a2·ew+a3·ns+a4·ew 2 +a5·ns 2 +a6·nτ

[0137] Δns=b1+k b t+b2·ew+b3·ns+b4·ew 2 +b5·ns 2

[0138] In the above formula, t represents time, k a The parameter that characterizes the time-varying east-west positioning deviation, k b Parameters that characterize the temporal variation of east-west positioning deviation. Δew represents the east-west positioning deviation, and Δns represents the north-south positioning deviation. ew represents the east-west pointing angle of the long linear array payload's two-dimensional scanning mechanism, and ns represents the east-west pointing angle of the long linear array payload's two-dimensional scanning mechanism. a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, while b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation. n represents the long linear array pixel number, and τ represents the pixel angular resolution of the long linear array payload.

[0139] Similarly, geometric control points at different times and spatial positions are used for observation, and the equivalent parameters are solved by the least squares method. The specific expression is as follows:

[0140]

[0141] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew nThe east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified for the nth geometric calibration. n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0142] a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation, and k a 、k b Characterizing the time-dependent positioning deviation equivalent parameters. By constructing the above linear equations and performing a least squares solution using multiple geometric calibration data, the above positioning deviation equivalent parameters can be solved, i.e., the positioning deviation solution model for long linear array loads including time.

[0143] 3) Long linear array load positioning deviation processing process

[0144] Based on the above analysis, when solving the positioning deviation of the long linear array payload, the solution of the rotation deformation parameter a6 of the long linear array detector requires that the pixel number difference of the geometric control point image in a set of geometric calibration is as large as possible. However, due to the influence of observation constraints during geometric calibration, it is not possible to guarantee that each set of geometric calibration meets the requirements of solving the rotation deformation parameter of the long linear array detector. Therefore, a long linear array payload positioning deviation processing process is developed, see the attached Figure 4 , ensuring that different geometric calibration results can be solved. The detailed processing flow is as follows:

[0145] ① Obtain the input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point.

[0146] ② Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. The larger Δn is, the wider the distribution of the control points on the long linear array detector is, which is more conducive to the solution of the rotation deformation parameters of the long linear array detector.

[0147] ③ If Δn is greater than the long-line array positioning deviation calculation threshold, the calculation is performed according to the "positioning deviation calculation model including time variation" detailed in step 2.

[0148] ④ If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and the reduced-order solution method is used. Since the long-line array detector rotation only affects the east-west latitude positioning deviation, the reduced-order solution method is also only for the east-west dimension. The specific solution expression is as follows:

[0149]

[0150] In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n is the east-west positioning deviation identified by the nth geometric calibration, ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, is the rotational deformation parameter of the long linear array detector solved in the previous group, and τ represents the pixel angular resolution of the long linear array load.

[0151] 4) Design positioning deviation solution accuracy evaluation method

[0152] Each time the thermal deformation solution is completed using the geometric calibration data, the solution accuracy needs to be evaluated. The general process is as follows:

[0153] ① Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters. The calculation formula is as follows:

[0154]

[0155] In the above formula, is the theoretical positioning deviation of the east-west dimension of the nth geometric calibration calculated based on the deformation parameters, is the theoretical positioning deviation of the north-south dimension of the nth geometric calibration calculated based on the deformation parameters. n Represents the time corresponding to the nth geometric calibration. n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

[0156] ② By subtracting the actual positioning deviation from the theoretical positioning deviation, the accuracy of the positioning deviation calculation can be evaluated:

[0157]

[0158] In the above formula, The accuracy of the east-west dimension solution of the nth geometric calibration, is the north-south dimension solution accuracy of the nth geometric calibration. n Actual positioning deviation of the east-west dimension in the nth geometric calibration, Δns n is the actual positioning deviation of the north-south dimension after the nth geometric calibration. The theoretical positioning deviation of the east-west dimension for the nth geometric calibration is: is the theoretical positioning deviation of the north-south dimension after the nth geometric calibration.

[0159] 5) Improved positioning deviation calculation accuracy

[0160] The calculation of positioning deviation depends on the results of multiple geometric calibrations. If a certain geometric calibration produces a significant error, it will cause an overall calculation error. Therefore, it is necessary to design a method to improve the accuracy of positioning deviation calculation and optimize it according to the accuracy evaluation results of geometric calibration. See the attached Figure 5 , the specific processing flow for improving the solution accuracy is as follows:

[0161] ① According to the method described above, complete the positioning deviation solution accuracy assessment. If all solution errors are less than the error threshold, it means that the solution is normal and the results can be output directly; otherwise, the next step is required.

[0162] ② Determine whether the number of geometric calibrations involved in the solution of this group is greater than the threshold. If not, it means that the solution has failed and the solution result is discarded; otherwise, the next step is required.

[0163] ③ Eliminate the geometric calibration results with the largest solution deviation, recalculate the positioning deviation for the remaining geometric calibration data, and repeat steps ① and ②.

[0164] Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1 and Embodiment 2.

[0165] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0166] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for calculating the positioning deviation of a long linear array payload of a geostationary meteorological satellite, characterized in that: The method comprises the following steps: Step S1: Based on the imaging principle of the long linear array payload, a positioning deviation calculation model is derived and constructed that takes into account the spatial dimensional changes caused by the payload optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors; Step S2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method. Step S3: constructing a long linear array load positioning deviation solution model, wherein the long linear array load positioning deviation solution model is used to process input information of positioning deviation, wherein the input information includes time, positioning deviation, pointing angle, and pixel number of geometric control point, and solve the positioning deviation according to the input information; Step S4: constructing a positioning deviation solution accuracy evaluation method, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy; Step S5: Design a method for improving the accuracy of positioning deviation solution that takes into account the accuracy of geometric calibration points, including after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, then determine whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, eliminate the geometric calibration result with the largest solution deviation and re-solve the positioning deviation for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

2. The method for calculating positioning deviation of a long linear array payload of a geostationary meteorological satellite according to claim 1, characterized in that: In step S1, the long linear array load positioning deviation calculation model also considers the positioning deviation linearly related to the load two-dimensional scanning mechanism angle, the positioning deviation related to the quadratic term of the load two-dimensional scanning mechanism angle, and the positioning deviation related to the long linear array. The established relationship between the positioning deviation and the spatial dimension is as follows: <h2 style=";text-align:left;direction:ltr">Δew = a1+a2ew+a3ns+a4ew<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +a5·ns<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +a6·nτ Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2 In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload; Parameters a1 and b1 represent the basic deviation of load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the angle of the load's two-dimensional scanning mechanism; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction.

3. The method for calculating positioning deviation of a geostationary meteorological satellite long linear array payload according to claim 1, characterized in that: In step S2, when using the positioning deviation solution model that includes time changes, it is necessary to consider the impact of satellite thermal deformation at different times on the positioning deviation, and solve the equivalent parameters through multiple geometric calibration data. The specific expression is as follows: In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

4. The method for calculating positioning deviation of a geostationary meteorological satellite long linear array payload according to claim 1, characterized in that: The step S3 comprises the following steps: Step S3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point; Step S3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. A larger Δn indicates a wider distribution of the control points on the long linear array detector, which is more conducive to solving the rotational deformation parameters of the long linear array detector. Step S3.3: If Δn is greater than the long-line array positioning deviation calculation threshold, the positioning deviation calculation model including time variation in step S2 is used for calculation; Step S3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution method is adopted.

5. The method for calculating positioning deviation of a geostationary meteorological satellite long linear array payload according to claim 1, characterized in that: The step S4 comprises the following steps: Step S4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters; Step S4.2: Evaluate the accuracy of the positioning deviation calculation by subtracting the actual positioning deviation from the theoretical positioning deviation.

6. The method for calculating positioning deviation of a geostationary meteorological satellite long linear array payload according to claim 1, characterized in that: The step S5 includes the following steps: Step S5.1: Complete the positioning deviation solution accuracy assessment according to step S4. If all solution errors are less than the error threshold, it means that the solution is normal and the result is directly output; otherwise, the next step needs to be processed; Step S5.2: Determine whether the number of geometric calibrations for this group is greater than a threshold. If not, the solution fails and the result is discarded. Otherwise, proceed to the next step. Step S5.3: Eliminate the geometric calibration result with the largest solution deviation, recalculate the positioning deviation for the remaining geometric calibration data, and repeat steps S5.1 and S5.

2.

7. A geostationary meteorological satellite long-array payload positioning deviation calculation system, characterized in that: The system includes the following modules: Module M1: Based on the imaging principle of the long linear array payload, derive and construct a positioning deviation calculation model that takes into account the spatial dimensional changes caused by the payload optical axis orientation and the spatial dimensional changes caused by the distribution of the long linear array detectors; Module M2: Considering the time-varying nature of on-orbit deformation, a positioning deviation calculation model that includes time variations is introduced. Observations are performed using geometric control points at different times and spatial positions, and the equivalent parameters are solved using the least squares method. Module M3: Constructing a long-line array payload positioning deviation calculation model, which is used to process input information of positioning deviation, including time, positioning deviation, pointing angle, and pixel number of geometric control points, and calculate the positioning deviation based on the input information; Module M4: Constructing a positioning deviation solution accuracy evaluation system, including calculating the theoretical positioning deviation of each geometric calibration based on the solved thermal deformation parameters, and comparing the actual positioning deviation with the theoretical positioning deviation to evaluate the solution accuracy; Module M5: Design a positioning deviation solution accuracy improvement system that takes into account the accuracy of geometric calibration points. This includes, after completing the positioning deviation solution accuracy evaluation, if the solution error is greater than the error threshold, determining whether the number of geometric calibrations involved in the solution is greater than the threshold. If so, the geometric calibration result with the largest solution deviation is eliminated, and the positioning deviation solution is recalculated for the remaining geometric calibration data until the solution error is less than the error threshold or no more geometric calibration results can be eliminated.

8. The geostationary meteorological satellite long linear array payload positioning deviation calculation system according to claim 7, characterized in that: In module M1, the long linear array load positioning deviation calculation model also considers the positioning deviation linearly related to the load two-dimensional scanning mechanism angle, the positioning deviation related to the quadratic term of the load two-dimensional scanning mechanism angle, and the positioning deviation related to the long linear array. The established relationship between the positioning deviation and the spatial dimension is as follows: <h2 style=";text-align:left;direction:ltr">Δew = a1+a2ew+a3ns+a4ew<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +a5·ns<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +a6·nτ Δns=b1+b2·ew+b3·ns+b4·ew 2 +b5·ns 2 In the above formula, Δew is the east-west positioning deviation, Δns is the north-south positioning deviation, ew represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload, ns represents the east-west pointing angle of the two-dimensional scanning mechanism of the long linear array payload; a1, a2, a3, a4, a5, and a6 represent the equivalent parameters of the east-west positioning deviation, and b1, b2, b3, b4, and b5 represent the equivalent parameters of the north-south positioning deviation; n represents the pixel number of the long linear array, and τ represents the pixel angular resolution of the long linear array payload; Parameters a1 and b1 represent the basic deviation of the load positioning; parameters a4, a5, b2, and b3 represent the positioning deviation linearly related to the angle of the load's two-dimensional scanning mechanism; parameters a2, a3, b4, and b5 represent the positioning deviation related to the quadratic term of the load's two-dimensional scanning mechanism angle; parameter a6 represents the positioning deviation related to the long linear array and only affects the east-west direction; In module M2, when using the positioning deviation solution model that includes time changes, it is necessary to consider the impact of satellite thermal deformation on positioning deviation at different times, and solve the equivalent parameters through multiple geometric calibration data. The specific expression is as follows: In the above formula, t n Characterizes the time corresponding to the nth geometric calibration, Δew n The east-west positioning deviation identified by the nth geometric calibration, Δns n The north-south positioning deviation identified by the nth geometric calibration; ew n is the east-west pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, ns n is the north-south pointing angle of the two-dimensional scanning mechanism corresponding to the nth geometric calibration, n n is the pixel number of the long linear array detector corresponding to the geometric control point of the nth geometric calibration, and τ represents the pixel angular resolution of the long linear array payload.

9. The geostationary meteorological satellite long linear array payload positioning deviation calculation system according to claim 7, characterized in that: The module M3 includes the following modules: Module M3.1: Obtain input information for positioning deviation processing, including the time corresponding to each geometric calibration, east-west positioning deviation, north-south positioning deviation, east-west pointing angle, north-south pointing angle, and pixel number of the geometric control point; Module M3.2: Sort the pixel numbers of the geometric control points by size and calculate the maximum pixel number deviation Δn. The larger Δn is, the wider the distribution of the control points on the long linear array detector is, and the more conducive it is to solving the rotation deformation parameters of the long linear array detector. Module M3.3: If Δn is greater than the long-line array positioning deviation solution threshold, the positioning deviation solution model containing time variation in module M2 is used for solution. Module M3.4: If Δn is less than the long-line array positioning deviation solution threshold, the last long-line array detector rotation deformation parameter is referenced and a reduced-order solution system is used; The module M4 includes the following modules: Module M4.1: Calculate the theoretical positioning deviation of each geometric calibration based on the calculated thermal deformation parameters; Module M4.2: Evaluate the accuracy of positioning deviation calculation by subtracting the actual positioning deviation from the theoretical positioning deviation.

10. The geostationary meteorological satellite long linear array payload positioning deviation calculation system according to claim 7, characterized in that: The module M5 includes the following modules: Module M5.1: Complete the positioning deviation solution accuracy assessment based on module M4. If all solution errors are less than the error threshold, it means that the solution is normal and the results are output directly; otherwise, the next step is required. Module M5.2: Determine whether the number of geometric calibrations of this group involved in the solution is greater than the threshold. If not, it means that the solution has failed and the solution result is discarded. Otherwise, the next step is required. Module M5.3: Eliminate the geometric calibration results with the largest solution deviation, recalculate the positioning deviation of the remaining geometric calibration data, and repeatedly call modules M5.1 and M5.2.

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