Geometric calibration and correction method for infrared hyperspectral atmospheric detector

Abstract

The invention relates to the technical field of satellite remote sensing, in particular to a geometric calibration and correction method for an infrared hyperspectral atmospheric detector, which comprises the following steps of: constructing the direction of optical axis light of a field of view of the detector in a satellite body coordinate system pixel by pixel; acquiring the rotation angle of the scanning mirror, calculating the normal direction of the plane mirror, and calculating the direction of reflected light by adopting a reflector formula; acquiring an orbit position and an attitude rotation matrix of a satellite body under an earth-fixed coordinate system; constructing an infrared hyperspectral detector imaging geometric positioning equation, and intersecting a visual axis direction with an earth ellipsoid to obtain a three-dimensional coordinate of a ground point; registering data of the infrared hyperspectral detector with a high-resolution image on the same platform, acquiring geometric coordinates of the high-resolution image as control points, and solving an installation error matrix of the rotating mirror by adopting least square iteration; and substituting the view field parameters of different detectors for calculation to generate the image element geographic coordinates of the infrared hyperspectral detector after geometric correction, thereby realizing error correction from an imaging source.

Description

Technical Field

[0001] This invention relates to the field of satellite remote sensing technology, and in particular to a geometric calibration and correction method for an infrared hyperspectral atmospheric sounder. Background Technology

[0002] Currently, all of my country's Fengyun-3 sun-synchronous orbit satellites are equipped with an Infrared Hyperspectral Imager (HIRAS). This instrument uses a point-scan imaging method, where the imager mechanically scans in a direction perpendicular to its flight trajectory, while the satellite platform moves along the flight direction, together forming a two-dimensional image. Based on Michelson interferometry and Fourier transform spectroscopy, HIRAS can acquire continuous and ultra-fine infrared spectral data, which can be used to retrieve high-precision atmospheric temperature, humidity profiles, and atmospheric composition information. Furthermore, by assimilating this data in numerical weather prediction models, forecast accuracy can be improved.

[0003] The Fengyun-3 satellite's scanning instrument rotates in the transorbital direction via its scanning mirror, sequentially conducting Earth observations, cold-space background observations, and internal blackbody calibration, achieving a nadir point resolution of approximately 14 km and a swath width of approximately 2300 km. The FY3D satellite carries a 4-pixel hyperspectral infrared detector (HIRAS) (2×2 array), while the FY3E, FY3F, and FY3H satellites have been upgraded to a 9-pixel (3×3 array). During ground geometry processing, information such as satellite orbit, attitude, imaging time, scanning mirror dwell (FOR) angle, and point pixel field of view (FOV) position is combined to construct a geometric positioning model for the point-scanning imaging instrument, obtaining the latitude and longitude and observation geometric parameters for each pixel.

[0004] Domestic scholars (using the FY-3E platform imager to evaluate the positioning and calibration accuracy of HIRAS-II) have used the geographic coordinates of HIRAS L1 data, combined with high-resolution MERSI imagery from the same platform for registration, to evaluate the geometric performance of the HIRAS payload, but have not further achieved compensation and correction for positioning errors. For similar payloads like the CrIS carried by US meteorological satellites such as NPP and JPSS, foreign scholars (Improved scheme for Cross-track Infrared Soundergeolocation assessment and optimization) have performed geometric corrections. Their method involves progressively adjusting the angles along the track and perpendicular to the track, then calculating the registration error to find the offset parameters for each field of view (FOV). This method has several drawbacks: it does not consider the three-dimensional angle errors during mirror installation, only the errors in two directions; the errors between different FORs are correlated, and coefficients obtained through individual correction may contain random errors; and each angle adjustment requires extensive pixel registration calculations, which is detrimental to subsequent updates of geometric calibration parameters. The IASI payload, carried by the European MetOp series satellites, has higher spectral dimensions and more refined spectra. However, research on geometric correction procedures and methods for such hyperspectral payloads is still relatively limited.

[0005] Because the Infrared Hyperspectral Imager (HIRAS) employs a rotating mirror structure, the FOR image formed by multiple pixels in a single row exhibits image rotation along the vertical track. This causes its geometric positioning error to display different patterns in the track-along and cross-track directions compared to conventional cross-track scanning, making traditional instrument mounting matrix calibration methods unsuitable. Therefore, constructing a geometric calibration model suitable for the Infrared Hyperspectral Imager (HIRAS) and improving the scanning mirror pointing accuracy is of significant practical importance for enhancing the data quality of the HIRAS. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a geometric calibration and correction method for an infrared hyperspectral atmospheric sounder (HIRAS). It presents a geometric positioning model for the sweeping imaging of the HIRAS, which accurately describes the HIRAS imaging process. Based on this model, a geometric calibration error equation is constructed for the first time. By solving for the installation error parameters of the rotating scanning mirror, the geometric positioning correction of HIRAS data from the Fengyun-3 series operational satellites is achieved. In particular, it can compensate for and correct the inconsistency between the edge of a line of HIRAS imaging and the reference base map.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] This invention provides a geometric calibration and correction method for an infrared hyperspectral atmospheric sounder, comprising the following steps:

[0009] The orientation of the line-of-sight rays of the detector's field of view (FOV) in the satellite body coordinate system is constructed pixel by pixel and then normalized.

[0010] Based on the shooting time of the dwell field of view (FOR), the rotation angle of the scanning mirror is obtained, and the normal direction of the plane mirror is calculated, including installation error correction;

[0011] Based on the corrected plane mirror normal direction, the direction of the reflected light is calculated using the mirror formula;

[0012] Based on the shooting time of the dwell field of view, the attitude Euler angles are interpolated from the attitude measurement system to obtain the orbital position and attitude rotation matrix of the satellite body in the ground-fixed coordinate system;

[0013] Construct the imaging geometric positioning equation of the Infrared Hyperspectral Detector (HIRAS), intersect the line of sight with the Earth ellipsoid, and obtain the three-dimensional coordinates of the ground points;

[0014] The data from the Infrared Hyperspectral Imager (HIRAS) was registered with the high-resolution image on the same platform. The geometric coordinates of the high-resolution image were used as control points, and the installation error matrix of the rotating mirror was solved by least squares iteration.

[0015] By substituting the field of view (FOV) parameters of different detectors into the calculation and applying the corrected installation error matrix, the geometrically corrected geographic coordinates of the infrared hyperspectral detector (HIRAS) pixels are generated.

[0016] As a further aspect of the present invention, the orientation of the line-of-sight rays of the detector's field of view (FOV) in the satellite body coordinate system is constructed pixel by pixel and normalized, including the following steps:

[0017] Based on the position coordinates of each detector's field of view (FOV) on the detector's focal plane Calculate the normalized pointer vector ,in, Indicates matrix transpose. , Suitable for multiple detector fields of view (FOV) (e.g.) to Based on the position of the detector's field of view (FOV) on the detector's focal plane, the pointing of different detector FOVs is constructed and normalized.

[0018] As a further aspect of the present invention, the rotation angle of the scanning mirror is obtained based on the shooting time of the dwell field of view (FOR), and the normal direction of the plane mirror is calculated, including the following steps:

[0019] Based on the initial direction of the scanning mirror normal Construct the normal direction vector in the satellite body coordinate system;

[0020] Based on the measured angle of the motor during the scanning mirror's observation in the field of view (FOR), calculate the rotation angle of the scanning mirror along the satellite's X-axis. and rotate angle Convert to rotation matrix , Then the direction of the normal after rotation is ;

[0021] According to the installation error matrix of the scanning mirror to be corrected Correct the direction of the normal. Among them, the installation error matrix Euler angles from satellite body coordinate system to orbital coordinate system Composition, rotating Euler angles according to the ZXY rotation order, and using... Variable substitution expression: .

[0022] As a further aspect of the present invention, the direction of the reflected light is calculated using the mirror formula based on the corrected plane mirror normal direction. The calculation formula is as follows:

[0023]

[0024] In the formula, The direction of the line of sight after being reflected by the mirror. The direction of the line of sight before reflection by the mirror. Substitute the expression for the variable.

[0025] As a further aspect of the present invention, based on the shooting time of the dwell field of view, the attitude Euler angles are interpolated from the attitude measurement system to obtain the orbital position and attitude rotation matrix of the satellite body in the Earth-fixed coordinate system, including the following steps:

[0026] Based on the shooting time of the field of view (FOR) Obtain the orbital position of the satellite in the Earth-fixed coordinate system. and attitude rotation matrix At that time, the attitude Euler angles are interpolated from the attitude measurement system to construct the transformation matrix from the satellite body to the orbital coordinate system. ;

[0027] calculate The position vector of a satellite in an inertial frame at any given time and velocity vector Construct the transformation matrix from the orbital coordinate system to the geocentric inertial coordinate system. ;

[0028] according to Using time and Earth's rotation parameters, obtain the rotation matrix from the geocentric inertial frame to the Earth-fixed coordinate system. ;

[0029] Finally, the rotation matrix from the satellite body to the Earth-fixed coordinate system is obtained. .

[0030] As a further aspect of the present invention, an imaging geometric positioning equation for an infrared hyperspectral imager (HIRAS) is constructed, and the intersection of the line of sight with the Earth ellipsoid is determined to obtain the three-dimensional coordinates of ground points. This includes the following steps:

[0031] Constructing the collinearity equations for HIRAS geometric positioning:

[0032] ;

[0033] in, These are the coordinates of the ground point where the ray's line of sight intersects the Earth's ellipsoid. This is the scaling factor;

[0034] Based on the ellipsoid parameters and the elevation DEM data, the ellipsoid equation is constructed as follows:

[0035] ;in, Let be the semi-major axis of the ellipsoid in the WGS84 coordinate system. Let be the minor semi-axis of the ellipsoid in the WGS84 coordinate system. The DEM elevation of this ground point;

[0036] Solve for the scaling factor of the view vector The coordinates of the ground points after the intersection are obtained. .

[0037] As a further aspect of the present invention, the geometric coordinates of the high-resolution image are obtained as follows: As control points, the installation error rotation matrix of the rotating mirror is solved using least squares. This includes the following steps:

[0038] The data from the infrared hyperspectral detector were registered with the high-resolution MERSI image from the same platform, and the obtained geometric coordinates were used as control points to construct the adjustment equations for the least squares solution:

[0039] ;

[0040] Based on the imaging time, FOR angle, attitude, and trajectory, the adjustment equation for solving the installation error is constructed. Through model linearization, the error equation is obtained as follows: ;in, For installation angle The amount of correction, The Jacobian matrix of the error equation for the observations with respect to the installation angle. is the constant vector of the observation error equation;

[0041] Solving by least squares ,in, To determine the number of control points, update the installation angle based on the correction calculated using the least squares method. The installation angle is iteratively updated until convergence, and the iteration ends when the results of two updates are less than the limit difference.

[0042] As a further aspect of the present invention, when generating the geometrically corrected geographic coordinates of infrared hyperspectral imager (HIRAS) pixels, the field-of-view (FOV) parameters of different imagers are substituted into the calculation to obtain the corresponding... Correction value, the corrected value Substitute the correction value into the geometric positioning equation to generate the geometrically corrected HIRAS pixel geographic coordinates.

[0043] Compared with existing technologies, the geometric calibration and correction method for the Infrared Hyperspectral Atmospheric Sounder (HIRAS) provided by this invention, based on the application requirements of the Fengyun-3 series operational satellites, achieves a significant improvement in pixel-level geometric accuracy through the constructed geometric positioning model and error correction equations, and has the following beneficial effects:

[0044] This invention is the first to construct a geometric positioning model for HIRAS oscillating scanning imaging and directly solves for the installation error parameters of the rotating scanning mirror through the geometric calibration error equation. This achieves error correction from the imaging source, avoiding the risk of secondary errors caused by inaccurate error verification, and specifically compensates for the inconsistency between the imaging edge and the reference base map. The method of this invention is applicable to various FOV (field of view) configurations and supports the direct use of quaternions to replace Euler angles to obtain the attitude matrix from the satellite body to the inertial frame, without relying on multiple conversions of orbital position, velocity, and Euler angle parameters, thus improving calibration efficiency. This invention also proposes a complete geometric calibration and correction method for HIRAS detectors for the first time, organically combining the geometric positioning model with the error equation. It not only corrects pixel coordinates but also corrects the scanning mirror pointing through the installation error matrix, improving accuracy from the hardware level. This significantly improves the geometric positioning accuracy of HIRAS data, ensuring the leading position of HIRAS detectors in the field of infrared hyperspectral atmospheric detection.

[0045] These or other aspects of the invention will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. In the drawings:

[0047] Figure 1 This is a flowchart of a geometric calibration and correction method for an infrared hyperspectral atmospheric detector according to the present invention.

[0048] Figure 2 This is a schematic diagram of the focal plane structure of the HIRAS detector of the FY3-E / F / H satellite in the geometric calibration and correction method of an infrared hyperspectral atmospheric detector of the present invention.

[0049] Figure 3 This is a schematic diagram of the HIRAS rotating mirror line-of-sight detection principle in the geometric calibration and correction method of an infrared hyperspectral atmospheric detector according to the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0051] The technical solutions in the exemplary embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described exemplary embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] See Figure 1 and Figure 3 As shown, embodiments of this application also provide a geometric calibration and correction method for an infrared hyperspectral atmospheric sounder, comprising the following steps:

[0053] Step S10: Construct the direction of the line-of-sight rays of the detector's field of view (FOV) in the satellite body coordinate system pixel by pixel, and perform normalization processing.

[0054] In this step, see Figure 2As shown, the orientation of the line-of-sight rays of the detector's field of view (FOV) in the satellite's body coordinate system is constructed pixel by pixel and normalized, including the following steps:

[0055] Based on the position coordinates of each detector's field of view (FOV) on the detector's focal plane Calculate the normalized pointer vector ,in, Indicates matrix transpose. , Suitable for multiple detector fields of view (FOV) (e.g.) to Based on the position of the detector's field of view (FOV) on the detector's focal plane, the pointing of different detector FOVs is constructed and normalized.

[0056] Step S20: Based on the shooting time of the dwell field of view (FOR), obtain the rotation angle of the scanning mirror and calculate the normal direction of the plane mirror.

[0057] In this step, see Figure 3 As shown, the specific steps include:

[0058] Step S201: According to the initial direction of the scanning mirror normal Construct the normal direction vector in the satellite body coordinate system;

[0059] Step S202: Calculate the rotation angle of the scanning mirror in the X-axis direction of the satellite based on the measured angle of the motor when the scanning mirror is detecting in the dwell field of view (FOR). and rotate angle Convert to rotation matrix , Then the direction of the normal after rotation is ;

[0060] Step S203: Based on the installation error matrix of the scanning mirror to be corrected Correct the direction of the normal. Among them, the installation error matrix Euler angles from satellite body coordinate system to orbital coordinate system Composition, rotating Euler angles according to the ZXY rotation order, and using... Variable substitution expression: .

[0061] Step S30: Calculate the direction of the reflected light using the mirror formula based on the corrected plane mirror normal direction.

[0062] In this step, the direction of the reflected ray is calculated using the mirror formula based on the corrected plane mirror normal direction. The formula is as follows:

[0063]

[0064] In the formula, The direction of the line of sight after being reflected by the mirror. The direction of the line of sight before reflection by the mirror. Substitute the expression for the variable.

[0065] Step S40: Based on the shooting time of the dwell field of view, interpolate the attitude Euler angles from the attitude measurement system to obtain the orbital position and attitude rotation matrix of the satellite body in the ground-fixed coordinate system.

[0066] In this step, based on the shooting time of the dwell field of view, the attitude Euler angles are interpolated from the attitude measurement system to obtain the orbital position and attitude rotation matrix of the satellite in the Earth-fixed coordinate system, including the following steps:

[0067] Step S401: Based on the shooting time of the field of view (FOR) Obtain the orbital position of the satellite in the Earth-fixed coordinate system. and attitude rotation matrix At that time, the attitude Euler angles are interpolated from the attitude measurement system to construct the transformation matrix from the satellite body to the orbital coordinate system. ;

[0068] Step S402, Calculation The position vector of a satellite in an inertial frame at any given time and velocity vector Construct the transformation matrix from the orbital coordinate system to the geocentric inertial coordinate system. ;

[0069] Step S403, according to Using time and Earth's rotation parameters, obtain the rotation matrix from the geocentric inertial frame to the Earth-fixed coordinate system. ;

[0070] Step S404: Finally, the rotation matrix from the satellite body to the Earth-fixed coordinate system is obtained. .

[0071] Step S50: Construct the imaging geometric positioning equation of the Infrared Hyperspectral Detector (HIRAS), intersect the line of sight with the Earth ellipsoid, and obtain the three-dimensional coordinates of the ground point.

[0072] In this step, the imaging geometric positioning equation of the Infrared Hyperspectral Imager (HIRAS) is constructed, and the intersection of the line of sight with the Earth ellipsoid is obtained to obtain the three-dimensional coordinates of the ground points. This includes the following steps:

[0073] Step S501: Construct the collinearity equations for HIRAS geometric positioning:

[0074] ;

[0075] in, These are the coordinates of the ground point where the ray's line of sight intersects the Earth's ellipsoid. This is the scaling factor;

[0076] Step S502: Construct the ellipsoid equation based on the ellipsoid parameters and the elevation DEM data:

[0077] ;in, Let be the semi-major axis of the ellipsoid in the WGS84 coordinate system. Let be the minor semi-axis of the ellipsoid in the WGS84 coordinate system. The DEM elevation of this ground point;

[0078] Solve for the scaling factor of the view vector The coordinates of the ground points after the intersection are obtained. .

[0079] Step S60: Register the data from the Infrared Hyperspectral Imager (HIRAS) with the high-resolution image on the same platform, obtain the geometric coordinates of the high-resolution image as control points, and use the least squares iterative method to solve for the installation error matrix of the rotating mirror. .

[0080] In this step, the geometric coordinates of the high-resolution image are obtained as follows: As control points, the installation error rotation matrix of the rotating mirror is solved using least squares. This includes the following steps:

[0081] Step S601: Register the infrared hyperspectral imager data with the high-resolution MERSI image on the same platform, and use the obtained geometric coordinates as control points to construct the adjustment equations for least squares solution:

[0082] ;

[0083] In this context, combining the control point coordinates, the HIRAS geometric positioning collinearity equation constructed in step S501 can be transformed into the following form:

[0084] .

[0085] Step S602: Based on the imaging time, FOR angle, attitude, and trajectory, construct the adjustment equation for the installation error calculation. The error equation is obtained through model linearization: ;in, For installation angle The amount of correction, The Jacobian matrix of the error equation for the observations with respect to the installation angle. This is the constant vector of the observation error equation; that is, the calculated value of the adjustment equation corresponding to this point, as follows:

[0086] ;

[0087] .

[0088] Step S603: Solve using least squares ,in, To determine the number of control points, update the installation angle based on the correction calculated using the least squares method. The installation angle is iteratively updated until convergence, and the iteration ends when the results of two updates are less than the limit difference.

[0089] Step S70: Substitute the field of view (FOV) parameters of different detectors into the calculation and apply the corrected installation error matrix. Generate geometrically corrected geographic coordinates of infrared hyperspectral detector (HIRAS) pixels.

[0090] In this step, when generating the geometrically corrected geographic coordinates of the infrared hyperspectral imager (HIRAS) pixels, the field of view (FOV) parameters of different imagers are substituted into the calculation to obtain the corresponding... Correction value, the corrected value Substitute the correction value into the geometric positioning equation to generate the geometrically corrected HIRAS pixel geographic coordinates.

[0091] This invention is the first to construct a geometric positioning model for HIRAS oscillating scanning imaging and directly solves for the installation error parameters of the rotating scanning mirror through the geometric calibration error equation. This achieves error correction from the imaging source, avoiding the risk of secondary errors caused by inaccurate error verification, and specifically compensates for the inconsistency between the imaging edge and the reference base map. The method of this invention is applicable to various FOV (field of view) configurations and supports the direct use of quaternions to replace Euler angles to obtain the attitude matrix from the satellite body to the inertial frame, without relying on multiple conversions of orbital position, velocity, and Euler angle parameters, thus improving calibration efficiency. This invention also proposes a complete geometric calibration and correction method for HIRAS detectors for the first time, organically combining the geometric positioning model with the error equation. It not only corrects pixel coordinates but also corrects the scanning mirror pointing through the installation error matrix, improving accuracy from the hardware level. This significantly improves the geometric positioning accuracy of HIRAS data, ensuring the leading position of HIRAS detectors in the field of infrared hyperspectral atmospheric detection.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for geometric calibration and correction of an infrared hyperspectral atmospheric sounder, characterized in that, The method comprises the following steps: The pointing of the optical axis of the field of view of the detector is constructed pixel by pixel in the satellite body coordinate system, and normalized processing is performed; According to the shooting time of the resident field of view, the rotation angle of the scanning mirror is obtained, and the normal direction of the plane mirror is calculated, including installation error correction; According to the corrected normal direction of the plane mirror, the pointing of the reflected light is calculated by using the mirror formula; According to the shooting time of the resident field of view, the Euler angle of the attitude is interpolated from the attitude measurement system, and the orbit position and attitude rotation matrix of the satellite body in the earth-fixed coordinate system are obtained; The imaging geometric positioning equation of the infrared hyperspectral detector is constructed, the pointing of the optical axis is intersected with the earth ellipsoid, and the three-dimensional coordinates of the ground points are obtained; The data of the infrared hyperspectral detector are registered with the high-resolution image of the same platform, the geometric coordinates of the high-resolution image are obtained as control points, and the installation error matrix of the rotating mirror is solved by using least square iteration; Different detector field of view parameters are substituted into the calculation, and the geometric corrected infrared hyperspectral detector pixel geographic coordinates are generated by using the corrected installation error matrix.

2. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 1, characterized in that, The pointing of the optical axis of the field of view of the detector is constructed pixel by pixel in the satellite body coordinate system, and normalized processing is performed, including the following steps: According to the position coordinates of each probe instrument field of view at the probe instrument focal plane , the normalized pointing vectors are calculated wherein , ; according to the position of the probe instrument field of view at the probe instrument focal plane, the pointing of different probe instrument fields of view is constructed and normalized.

3. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 2, characterized in that, According to the shooting time of the resident field of view, the rotation angle of the scanning mirror is obtained, and the normal direction of the plane mirror is calculated, including the following steps: According to the initial direction of the normal of the scanning mirror , construct the normal direction vector in the satellite body coordinate system; According to the measured angle of the motor of the scanning mirror when the scanning mirror is in the resident field of view detection, the rotation angle of the scanning mirror in the X-axis direction of the satellite is calculated , and the rotation angle is converted into a rotation matrix , , and the normal direction after rotation is ; According to the installation error matrix to be corrected of the scanning mirror Correcting the normal direction, Where the installation error matrix Euler angles from the satellite body coordinate system to the orbit coordinate system The Euler angles are rotated according to the rotation order of ZXY, and the expression is replaced by Variable replacement table 。 4. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 3, characterized in that, According to the corrected normal direction of the plane mirror, the pointing of the reflected light is calculated by using the mirror formula, and the calculation formula is: wherein is the line of sight direction after reflection by the mirror, is the line of sight direction before reflection by the mirror, is a variable substitution expression.

5. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 4, characterized in that, According to the shooting time of the resident field of view, the Euler angle of the attitude is interpolated from the attitude measurement system, and the orbit position and attitude rotation matrix of the satellite body in the earth-fixed coordinate system are obtained, including the following steps: According to the shooting time of the resident field of view , the orbit position of the satellite body under the earth-fixed coordinate system and the attitude rotation matrix are obtained ; Computing the position vector of the satellite in the inertial system at the time instant and the velocity vector , the conversion matrix of the orbital coordinate system to the geocentric inertial coordinate system ; According to the time and the earth rotation parameters, the rotation matrix from the geocentric inertial system to the earth-fixed coordinate system is obtained ; The rotation matrix of the satellite body to the earth-fixed coordinate system is finally obtained .

6. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 5, characterized in that, The imaging geometric positioning equation of the infrared hyperspectral detector is constructed, the pointing of the optical axis is intersected with the earth ellipsoid, and the three-dimensional coordinates of the ground points are obtained, including the following steps: The geometric positioning collinear equation of HIRAS is constructed: ； wherein, is the ground point coordinate after the light ray boresight intersects the Earth ellipsoid, is the scaling factor; According to the parameters of the ellipsoid, the ellipsoid equation is constructed in combination with the elevation DEM data: ; wherein, is the semi-major axis of the ellipsoid in the WGS84 coordinate system, is the semi-minor axis of the ellipsoid in the WGS84 coordinate system, is the DEM elevation of the ground point; Solving for scaling factor of view vector , to get the ground point coordinates after intersection .

7. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 6, characterized in that, The geometric coordinates of the high-score image are obtained As a control point, the installation error rotation matrix of the rotating mirror is solved by least squares , comprising the following steps: The data of the infrared hyperspectral detector are registered with the high-resolution MERSI image of the same platform, and the geometric coordinates obtained are used as control points to construct the adjustment equation for least square solution: ； According to the imaging time, the resident field angle, the attitude and the orbit, a mounting error solution adjustment equation is constructed, and the error equation is obtained through linearization of the model as follows: ; wherein, is a correction amount of the mounting angle, is a Jacobian matrix of the error equation of the observation value with respect to the mounting angle, is a constant vector of the error equation of the observation value.​ Solve by least square wherein, is the number of control points, update the installation angle according to the correction amount solved by least square , iteratively update the installation angle until convergence, and end the iteration when the results of two times of update are less than the limit difference.

8. The geometric calibration and correction method for infrared hyperspectral atmospheric sounder according to claim 7, characterized in that, When generating the geographic coordinates of the geometrically corrected infrared hyperspectral detector pixels, different detector field of view parameters are substituted into the calculation to obtain corresponding correction values, the corrected correction values are substituted into the geometric positioning equation to generate the geographic coordinates of the geometrically corrected HIRAS pixels.

Images