Fixed star sight atmospheric refraction correction method for optical satellite limb observation

Abstract

The invention provides a fixed star sight atmospheric refraction correction method for optical satellite limb observation, and the method comprises the steps: constructing an atmospheric ellipsoid model according to an earth atmosphere parameter set and earth ellipsoid parameters; according to the satellite orbit, the attitude measurement value, the image imaging time, the fixed star image plane coordinate and the satellite camera parameter, calculating the fixed star sight line; performing penetration layer atmospheric refraction correction on the fixed star sight line based on the atmospheric ellipsoid model to obtain a corrected first fixed star sight line; based on the atmosphere ellipsoid model, performing penetrating layer atmosphere refraction correction on the corrected first fixed star sight line to obtain a corrected second fixed star sight line; and calculating the right ascension and declination of the fixed star by using the corrected second fixed star sight line. According to the method, fixed star sight atmospheric refraction correction processing of optical satellite limb observation can be realized, so that support is provided for high-precision geometric processing of optical satellite limb observation images.

Description

Technical Field

[0001] The present invention relates to the field of optical satellite technology, and in particular to a method for correcting atmospheric refraction of a star's line of sight during limb observation by an optical satellite. Background Art

[0002] With the rapid development of satellite, remote sensing, and computer technologies, the spatial, temporal, and spectral resolutions of optical satellites have significantly increased. Furthermore, the rapid, agile, and maneuverable imaging capabilities of optical satellites have also been significantly enhanced. Compared to conventional optical satellites, agile optical satellites can not only observe and image the Earth's surface, but also the Earth's limb and deep space. This rapid, agile, and maneuverable imaging capability significantly improves the real-time monitoring and early warning capabilities of optical satellites.

[0003] Compared to imaging of the Earth's surface and deep space, optical satellite imaging of the Earth's limb is affected by atmospheric refraction, which bends the propagation path of the imaging light. Furthermore, the closer to the Earth's surface, the greater the atmospheric refractive index, and the greater the effect of atmospheric refraction on the satellite imaging light. This atmospheric refraction can make the collinearity condition equations commonly used in geometric processing of optical satellite images no longer strictly applicable, thereby reducing the accuracy of optical satellite line-of-sight determination. Therefore, to improve the accuracy of optical satellite line-of-sight determination, atmospheric refraction is an error factor that must be considered.

[0004] Stars are a very important type of reference data for optical satellite observation and imaging. They can be used to assess the accuracy of line-of-sight determination of optical satellite images, thus providing an effective reference for the accuracy assessment of target line-of-sight. Therefore, studying the atmospheric refraction correction of stellar line-of-sight in limb observations has important research significance and application value. Compared with deep space observations and Earth observations, limb observations are more complexly affected by atmospheric refraction. In deep space observation mode, star light does not pass through the atmosphere and can directly enter the satellite imaging payload, so it is not affected by atmospheric refraction; in Earth observation mode, the target light passes through the atmosphere before entering the satellite imaging payload and is affected by atmospheric refraction once; while in limb observation mode, star light first passes through the atmosphere, then exits the atmosphere, and then enters the satellite imaging payload, and is affected by atmospheric refraction twice.

[0005] Currently, there is little research on atmospheric refraction correction for stellar line of sight in limb observations of optical satellites, and it remains one of the key issues that need to be urgently addressed in high-precision geometric processing of optical satellites. Summary of the Invention

[0006] The present invention provides a method for correcting atmospheric refraction of the line of sight of stars in optical satellite limb observation, which is used to solve the defects existing in the prior art. The method calculates the line of sight of stars based on the satellite position and attitude measurement values, the image formation time, the coordinates of the star image plane, the camera parameters and the earth parameters, and performs atmospheric refraction correction processing on the line of sight of stars when entering and exiting the layer according to the atmospheric ellipsoid model, and then calculates the right ascension and declination of the stars after the atmospheric refraction correction.

[0007] In a first aspect, the present invention provides a method for correcting atmospheric refraction of a star's line of sight during optical satellite limb observation, comprising: Construct an atmospheric ellipsoid model based on the Earth's atmospheric parameter set and the Earth's ellipsoid parameters; Calculate the star line of sight based on the satellite orbit, attitude measurements, image formation time, star image plane coordinates and satellite camera parameters; Based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the star sight line to obtain a corrected first star sight line; Based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the corrected first star sight line to obtain a corrected second star sight line; The right ascension and declination of the star are calculated using the corrected second star sight line.

[0008] According to the present invention, a method for correcting atmospheric refraction of a star's line of sight for optical satellite limb observation is provided, which constructs an atmospheric ellipsoid model based on a set of Earth's atmospheric parameters and Earth's ellipsoid parameters, including: Based on the official data of 41 atmospheric isobaric surfaces and the absolute temperature, relative humidity and atmospheric pressure of 361×181 regular grid points on each isobaric surface, the atmospheric refraction coefficient of each regular grid point on each atmospheric isobaric surface is calculated. According to the earth ellipsoid parameters and the potential height of 41 atmospheric isobaric surfaces, the average ellipsoid height corresponding to each isobaric surface is calculated to obtain 41 atmospheric ellipsoid surfaces. Nine atmospheric ellipsoid surfaces are set at equal intervals between two adjacent atmospheric ellipsoid surfaces to obtain 411 atmospheric ellipsoid surfaces. The 411 layers of atmospheric ellipsoid surfaces are numbered from 1 to 411 in descending order according to the ellipsoid height. Based on the atmospheric refractive index, the atmospheric refractive index of each regular grid point on the 411 layers of atmospheric ellipsoid surfaces is obtained by linear interpolation to obtain the atmospheric ellipsoid model.

[0009] According to the present invention, a method for correcting atmospheric refraction of the line of sight of stars for optical satellite limb observation is provided, which calculates the line of sight of stars based on the satellite orbit, attitude measurement value, image imaging time, star image plane coordinates and satellite camera parameters, including: According to the satellite orbit and attitude measurement values ​​and the image imaging time, the satellite orbit parameters and satellite attitude parameters corresponding to the image imaging time are obtained by interpolation; Calculate the star view vector based on the image imaging time, satellite orbit parameters, satellite attitude parameters, star image plane coordinates, camera parameters and earth parameters:

[0010] Where, is the apparent vector of the star; The rotation matrix from the J2000 coordinate system to the WGS84 coordinate system; is the rotation matrix from the satellite orbit coordinate system to the J2000 coordinate system; is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; is the rotation matrix from the camera coordinate system to the satellite body coordinate system; , is the star image coordinate, is the camera principal distance; The star line of sight is obtained by taking the satellite orbit parameters corresponding to the image formation time as the starting point of the star line of sight and the star line of sight vector as the line of sight direction.

[0011] According to a method for correcting atmospheric refraction of a star line of sight for optical satellite limb observation provided by the present invention, based on the atmospheric ellipsoid model, the star line of sight is corrected for atmospheric refraction in the penetration layer to obtain a corrected first star line of sight, comprising: Taking the star line of sight as the current star line of sight and the first atmospheric ellipsoid as the current atmospheric ellipsoid, calculate the intersection of the current star line of sight and the current atmospheric ellipsoid; if the two do not intersect, it is determined that the current star line of sight does not pass through the Earth's atmosphere, and no atmospheric refraction correction is required, and the calculation of the star's right ascension and declination is directly performed; otherwise, the periintersection point is used as the current intersection point, and the next step of calculation is performed; According to the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid, the atmospheric refraction coefficients of the current intersection point on the current layer and the previous layer of atmospheric ellipsoid are interpolated; Calculate the normal vector of the current atmospheric ellipsoid at the current intersection point :

[0012] Where, are the major and minor axes of the atmospheric ellipsoid of the current layer, are the intersection coordinates, Indicates the number of the atmospheric ellipsoid; Calculate the incident angle of the current star's line of sight on the current atmospheric ellipsoid and refraction angle :

[0013]

[0014] Where, is the visual vector of the current star’s line of sight, and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Construct the current star's view vector , the apparent vector of the star after refraction and normal vector The coplanarity condition equation is:

[0015] Where, , , ;in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction; Further solve the star's visual vector after refraction:

[0016] Take the current intersection point as the starting point of the line of sight and the star view vector after refraction as the line of sight direction to obtain the new current star line of sight. Take the atmospheric ellipsoid of the next layer as the atmospheric ellipsoid of the current layer, and calculate the intersection point of the current star line of sight and the current atmospheric ellipsoid. If the two do not intersect, proceed to the next step of calculation. Otherwise, take the near intersection point as the current intersection point and re-enter the calculation of the atmospheric refraction coefficient of the current intersection point on the current and previous atmospheric ellipsoids.

[0017] According to a method for correcting atmospheric refraction of a stellar line of sight for optical satellite limb observation provided by the present invention, based on the atmospheric ellipsoid model, the atmospheric refraction correction of the first corrected stellar line of sight is performed through the layer to obtain a corrected second stellar line of sight, comprising: The atmospheric ellipsoid of the previous layer of the current layer is used as the new atmospheric ellipsoid of the current layer, and the intersection point of the current star line of sight and the atmospheric ellipsoid of the current layer is calculated, and the far intersection point is used as the current intersection point; According to the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid, the atmospheric refraction coefficients of the current intersection point on the previous and current atmospheric ellipsoids are obtained by interpolation; Calculate the normal vector of the current atmospheric ellipsoid at the current intersection point :

[0018] Where, is the intersection coordinate; Calculate the incident angle of the current star's line of sight on the current atmospheric ellipsoid and refraction angle :

[0019]

[0020] Where, is the visual vector of the current star line of sight; and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Construct the current star's view vector , the apparent vector of the star after refraction and normal vector The coplanarity condition equation is:

[0021] Where, , , ; in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction; Further solve the star's visual vector after refraction:

[0022] If the current atmospheric ellipsoid is the first atmospheric ellipsoid, then enter the calculation of the star's right ascension and declination. Otherwise, use the current intersection as the starting point of the line of sight and the star's visual vector after refraction as the line of sight direction to obtain a new current star line of sight. Use the previous atmospheric ellipsoid as the current atmospheric ellipsoid, and calculate the intersection of the current star line of sight and the current atmospheric ellipsoid. Then use the peri-intersection point as the current intersection, and re-enter the calculation of the atmospheric refraction coefficient of the current intersection on the previous and current atmospheric ellipsoids.

[0023] According to a method for correcting atmospheric refraction of stellar line of sight in optical satellite limb observation provided by the present invention, the set of Earth's atmospheric parameters includes the absolute temperature, relative humidity, atmospheric pressure and geopotential height of the Earth's atmosphere.

[0024] In a second aspect, the present invention further provides a star line-of-sight atmospheric refraction correction system for optical satellite limb observation, comprising: A construction module, used for constructing an atmospheric ellipsoid model according to a set of earth atmosphere parameters and earth ellipsoid parameters; The first calculation module is used to calculate the star line of sight based on the satellite orbit, attitude measurement value, image imaging time, star image plane coordinates and satellite camera parameters; A first correction module is configured to perform atmospheric refraction correction on the star sight line based on the atmospheric ellipsoid model to obtain a corrected first star sight line; A second correction module is configured to perform atmospheric refraction correction on the corrected first star sight line based on the atmospheric ellipsoid model to obtain a corrected second star sight line; The second calculation module is used to calculate the right ascension and declination of the star using the corrected second star sight line.

[0025] In a third aspect, the present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements any of the above-described methods for correcting atmospheric refraction of the line of sight of stars in optical satellite limb observation.

[0026] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the atmospheric refraction correction method for stellar line of sight in optical satellite limb observation as described in any of the above-mentioned methods.

[0027] In a fifth aspect, the present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-described methods for correcting atmospheric refraction of the line of sight of stars in optical satellite limb observation.

[0028] The present invention provides a method for correcting atmospheric refraction for stellar line-of-sight during optical satellite limb observation. First, an atmospheric ellipsoid model is constructed based on the absolute temperature, relative humidity, atmospheric pressure, geopotential height, and Earth ellipsoid parameters of the Earth's atmosphere. Secondly, the stellar line-of-sight is calculated based on satellite position and attitude measurements, image formation time, stellar image plane coordinates, camera parameters, and Earth parameters. Then, based on the atmospheric ellipsoid model, atmospheric refraction corrections are performed on the stellar line-of-sight for both the entry and exit layers. Finally, the stellar right ascension and declination are calculated based on the atmospheric refraction-corrected stellar line-of-sight. Based on the propagation characteristics of stellar light during optical satellite limb observation, the present invention can perform atmospheric refraction correction on the stellar line-of-sight layer by atmospheric layer, obtaining accurate stellar line-of-sight and stellar right ascension and declination, thereby providing effective support for the accuracy assessment of optical satellite image line-of-sight determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is one of the flow charts of the atmospheric refraction correction method for stellar line of sight in optical satellite limb observation provided by the present invention; Figure 2 This is the second flow chart of the atmospheric refraction correction method for stellar line of sight in optical satellite limb observation provided by the present invention; Figure 3 This is a schematic diagram of the atmospheric refraction correction of the star line of sight provided by the present invention Figure 4 This is a schematic structural diagram of the atmospheric refraction correction system for stellar line of sight for optical satellite limb observation provided by the present invention; Figure 5 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] Figure 1 FIG. 1 is a flow chart of a method for correcting atmospheric refraction of a star's line of sight for optical satellite limb observation provided by an embodiment of the present invention. Figure 1 Shown, including: Step 100: constructing an atmospheric ellipsoid model according to the Earth's atmosphere parameter set and the Earth's ellipsoid parameters; Step 200: Calculate the star line of sight based on the satellite orbit, attitude measurement value, image formation time, star image plane coordinates and satellite camera parameters; Step 300: Based on the atmospheric ellipsoid model, the star sight line is corrected for atmospheric refraction to obtain a corrected first star sight line; Step 400: Based on the atmospheric ellipsoid model, the corrected first star sight line is corrected for refraction through the atmosphere to obtain a corrected second star sight line; Step 500: Calculate the right ascension and declination of the star using the corrected second star sight line.

[0033] Specifically, in an embodiment of the present invention, an atmospheric ellipsoid model is first constructed based on the absolute temperature, relative humidity, atmospheric pressure, potential height and Earth ellipsoid parameters of the Earth's atmosphere; secondly, the star line of sight is calculated based on the satellite position and attitude measurement values, image imaging time, star image plane coordinates, camera parameters and Earth parameters; then, according to the atmospheric ellipsoid model, the star line of sight is corrected for atmospheric refraction entering and exiting the layer respectively; finally, based on the star line of sight after atmospheric refraction correction, the star's right ascension and declination are calculated to realize the atmospheric refraction correction of the star line of sight for optical satellite limb observation.

[0034] In one embodiment, Figure 2 As shown, the overall process includes the following steps: Step 1: construct an atmospheric ellipsoid model based on the absolute temperature, relative humidity, atmospheric pressure, geopotential height and earth ellipsoid parameters of the earth's atmosphere; Step 1.1: Based on the absolute temperature, relative humidity, and atmospheric pressure of the 41 atmospheric isobaric surfaces and the 361 × 181 regular grid points on each isobaric surface provided by the U.S. National Centers for Environmental Prediction, calculate the atmospheric refraction coefficient of each regular grid point on each atmospheric isobaric surface. Step 1.2: Calculate the mean ellipsoid height corresponding to each isobaric surface based on the Earth's ellipsoid parameters and the potential heights of the 41 atmospheric isobaric surfaces to obtain 41 atmospheric ellipsoid surfaces. Then, set 9 atmospheric ellipsoid surfaces at equal intervals between two adjacent atmospheric ellipsoid surfaces to obtain 411 atmospheric ellipsoid surfaces. Step 1.3: Number the 411 atmospheric ellipsoids from 1 to 411 in descending order according to the ellipsoid height. Based on the atmospheric refractive index calculated in step 1.1, interpolate the atmospheric refractive index of each regular grid point on the 411 atmospheric ellipsoids by linear interpolation to obtain the atmospheric ellipsoid model. Step 2: Calculate the star line of sight based on the satellite position and attitude measurements, the image formation time, the star image plane coordinates, and the satellite camera parameters; Step 2.1, based on the satellite orbit and attitude measurement values ​​and the image imaging time, interpolate to obtain the satellite orbit parameters and satellite attitude parameters corresponding to the image imaging time; Step 2.2: Calculate the star view vector based on the image imaging time, satellite orbit parameters, satellite attitude parameters, star image plane coordinates, camera parameters, and Earth parameters, as shown in Equation (1): (1) Where, is the apparent vector of the star; The rotation matrix from the J2000 coordinate system to the WGS84 coordinate system; is the rotation matrix from the satellite orbit coordinate system to the J2000 coordinate system; is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; is the rotation matrix from the camera coordinate system to the satellite body coordinate system; ,and is the star image coordinate, is the camera principal distance; Step 2.3: Use the satellite orbit parameters corresponding to the image formation time as the starting point of the star line of sight and the star view vector as the line of sight direction to obtain the star line of sight; Step 3, such as Figure 3 As shown, according to the atmospheric ellipsoid model, the star sight obtained in step 2 is corrected for refraction through the atmosphere to obtain the corrected star sight; In step 3.1, use the star line of sight from step 2.3 as the current star line of sight, and the first atmospheric ellipsoid from step 1.3 as the current atmospheric ellipsoid. Calculate the intersection of the current star line of sight and the current atmospheric ellipsoid. If the two do not intersect, it indicates that the current star line of sight does not pass through the Earth's atmosphere, and no atmospheric refraction correction is required. Go directly to step 5. If the two intersect, use the near intersection point as the current intersection point and go to step 3.2. Step 3.2, interpolating the atmospheric refraction coefficients of the current intersection point on the current layer and the previous layer of the atmospheric ellipsoid based on the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid; Step 3.3, calculate the normal vector of the current atmospheric ellipsoid at the current intersection point , as shown in formula (2): (2) Where, are the major and minor axes of the current atmospheric ellipsoid, are the intersection coordinates, Indicates the number of the atmospheric ellipsoid; Step 3.4, calculate the incident angle of the current star line of sight on the current atmospheric ellipsoid and refraction angle , as shown in formula (3) and formula (4) respectively: (3) (4) Where, is the visual vector of the current star line of sight; and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Step 3.5, construct the current star's visual vector , the apparent vector of the star after refraction and normal vector The coplanar condition equation is shown in formula (5): (5) Where, , , ;in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction.

[0035] According to formula (5), the star's visual vector after refraction is calculated as shown in formula (6): (6) Step 3.6: Use the current intersection point as the starting point of the line of sight and the refracted star's line of sight vector as the line of sight direction to obtain the new current star line of sight. Use the next atmospheric ellipsoid as the current atmospheric ellipsoid and calculate the intersection point of the current star line of sight with the current atmospheric ellipsoid. If the two do not intersect, proceed to step 4; if they do intersect, use the near intersection point as the current intersection point and re-enter step 3.2. Step 4, such as Figure 3 As shown, according to the atmospheric ellipsoid model, the star sight obtained in step 3 is corrected for refraction through the atmosphere to obtain the corrected star sight; Step 4.1: Using the atmospheric ellipsoid of the previous layer in step 3.6 as the new atmospheric ellipsoid of the current layer, calculate the intersection point between the current star line of sight and the atmospheric ellipsoid of the current layer, and use the far intersection point as the current intersection point; Step 4.2, interpolating the atmospheric refraction coefficients of the current intersection point on the previous and current atmospheric ellipsoids based on the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid; Step 4.3, calculate the normal vector of the current atmospheric ellipsoid at the current intersection point , as shown in formula (7): (7) Where, is the intersection coordinate; Step 4.4, calculate the incident angle of the current star line of sight on the current atmospheric ellipsoid and refraction angle , as shown in formula (8) and formula (9) respectively: (8) (9) Where, is the visual vector of the current star line of sight; and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Step 4.5: Construct the current star's visual vector , the apparent vector of the star after refraction and normal vector The coplanar condition equation is shown in formula (10): (10) Where, , , ;in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction.

[0036] According to formula (10), the star's visual vector after refraction is calculated as shown in formula (11): (11) In step 4.6, if the current atmospheric ellipsoid is the first atmospheric ellipsoid, proceed to step 5. Otherwise, use the current intersection point as the starting point of the line of sight and the refracted star view vector as the line of sight direction to obtain a new current star line of sight. Use the previous atmospheric ellipsoid as the current atmospheric ellipsoid, calculate the intersection point of the current star line of sight with the current atmospheric ellipsoid, and then use the near intersection point as the current intersection point and re-enter step 4.2. Step 5: Calculate the right ascension and declination of the star based on the line of sight of the star obtained in step 4.

[0037] The star right ascension and declination after atmospheric refraction correction are obtained, and the atmospheric refraction correction processing of the star line of sight in the optical satellite limb observation is realized, and the atmospheric refraction correction work of the star line of sight is completed.

[0038] The atmospheric refraction correction system for stellar line of sight for optical satellite limb observation provided by the present invention is described below. The atmospheric refraction correction system for stellar line of sight for optical satellite limb observation described below and the atmospheric refraction correction method for stellar line of sight for optical satellite limb observation described above can be referenced to each other.

[0039] Figure 4 FIG. 1 is a schematic diagram of the structure of the atmospheric refraction correction system for stellar line of sight for optical satellite limb observation provided by an embodiment of the present invention. Figure 4As shown, it includes: a construction module 41, a first calculation module 42, a first correction module 43, a second correction module 44 and a second calculation module 45, wherein: The construction module 41 is used to construct an atmospheric ellipsoid model based on the set of Earth's atmospheric parameters and the Earth's ellipsoid parameters; the first calculation module 42 is used to calculate the star line of sight based on the satellite orbit, attitude measurement value, image imaging time, star image plane coordinates and satellite camera parameters; the first correction module 43 is used to perform atmospheric refraction correction on the star line of sight based on the atmospheric ellipsoid model to obtain a corrected first star line of sight; the second correction module 44 is used to perform atmospheric refraction correction on the corrected first star line of sight based on the atmospheric ellipsoid model to obtain a corrected second star line of sight; the second calculation module 45 is used to use the corrected second star line of sight to calculate the right ascension and declination of the star.

[0040] Figure 5 An example of a physical structure diagram of an electronic device is shown below. Figure 5 As shown, the electronic device may include: a processor 510, a communications interface 520, a memory 530, and a communications bus 540, wherein the processor 510, the communications interface 520, and the memory 530 communicate with each other via the communications bus 540. The processor 510 may call logic instructions in the memory 530 to execute a method for atmospheric refraction correction of star sight lines for optical satellite limb observations. The method includes: constructing an atmospheric ellipsoid model based on a set of Earth's atmospheric parameters and Earth's ellipsoid parameters; calculating star sight lines based on satellite orbits, attitude measurements, image formation time, star image plane coordinates, and satellite camera parameters; correcting the star sight lines for atmospheric refraction in the entry layer based on the atmospheric ellipsoid model to obtain a corrected first star sight line; correcting the corrected first star sight line for atmospheric refraction in the exit layer based on the atmospheric ellipsoid model to obtain a corrected second star sight line; and calculating the right ascension and declination of the star using the corrected second star sight line.

[0041] Furthermore, the logic instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0042] On the other hand, the present invention also provides a computer program product, which includes a computer program, and the computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the atmospheric refraction correction method for star line of sight of optical satellite limb observation provided by the above methods. The method includes: constructing an atmospheric ellipsoid model based on a set of Earth's atmospheric parameters and Earth's ellipsoid parameters; calculating the star line of sight based on the satellite orbit, attitude measurement value, image imaging time, star image plane coordinates and satellite camera parameters; based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the star line of sight into the layer to obtain a corrected first star line of sight; based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the star line of sight out of the layer to obtain a corrected second star line of sight; using the corrected second star line of sight to calculate the right ascension and declination of the star.

[0043] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the atmospheric refraction correction method for stellar line of sight for optical satellite limb observation provided by the above-mentioned methods. The method includes: constructing an atmospheric ellipsoid model based on a set of Earth's atmospheric parameters and Earth's ellipsoid parameters; calculating the stellar line of sight based on the satellite orbit, attitude measurement values, image imaging time, stellar image plane coordinates and satellite camera parameters; based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the stellar line of sight into the penetration layer to obtain a corrected first stellar line of sight; based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the corrected first stellar line of sight through the exit layer to obtain a corrected second stellar line of sight; and using the corrected second stellar line of sight to calculate the right ascension and declination of the star.

[0044] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0045] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for correcting atmospheric refraction of the line of sight of stars in optical satellite limb observation, characterized in that: include: Construct an atmospheric ellipsoid model based on the Earth's atmospheric parameter set and the Earth's ellipsoid parameters; Calculate the star line of sight based on the satellite orbit, attitude measurements, image formation time, star image plane coordinates and satellite camera parameters; Based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the star sight line to obtain a corrected first star sight line; Based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the corrected first star sight line to obtain a corrected second star sight line; The right ascension and declination of the star are calculated using the corrected second star sight line.

2. The method for correcting atmospheric refraction of stellar line of sight for optical satellite limb observation according to claim 1, characterized in that: According to the Earth's atmospheric parameters and the Earth's ellipsoid parameters, an atmospheric ellipsoid model is constructed, including: Based on the official data of 41 atmospheric isobaric surfaces and the absolute temperature, relative humidity and atmospheric pressure of 361×181 regular grid points on each isobaric surface, the atmospheric refraction coefficient of each regular grid point on each atmospheric isobaric surface is calculated. According to the earth ellipsoid parameters and the potential height of 41 atmospheric isobaric surfaces, the average ellipsoid height corresponding to each isobaric surface is calculated to obtain 41 atmospheric ellipsoid surfaces. Nine atmospheric ellipsoid surfaces are set at equal intervals between two adjacent atmospheric ellipsoid surfaces to obtain 411 atmospheric ellipsoid surfaces. The 411 layers of atmospheric ellipsoid surfaces are numbered from 1 to 411 in descending order according to the ellipsoid height. Based on the atmospheric refractive index, the atmospheric refractive index of each regular grid point on the 411 layers of atmospheric ellipsoid surfaces is obtained by linear interpolation to obtain the atmospheric ellipsoid model.

3. The method for correcting atmospheric refraction of stellar line of sight for optical satellite limb observation according to claim 1, characterized in that: Calculate the star line of sight based on the satellite orbit, attitude measurements, image formation time, star image plane coordinates and satellite camera parameters, including: According to the satellite orbit and attitude measurement values ​​and the image imaging time, the satellite orbit parameters and satellite attitude parameters corresponding to the image imaging time are obtained by interpolation; Calculate the star view vector based on the image imaging time, satellite orbit parameters, satellite attitude parameters, star image plane coordinates, camera parameters and earth parameters: Where, is the apparent vector of the star; The rotation matrix from the J2000 coordinate system to the WGS84 coordinate system; is the rotation matrix from the satellite orbit coordinate system to the J2000 coordinate system; is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; is the rotation matrix from the camera coordinate system to the satellite body coordinate system; , is the star image coordinate, is the camera principal distance; The star line of sight is obtained by taking the satellite orbit parameters corresponding to the image formation time as the starting point of the star line of sight and the star line of sight vector as the line of sight direction.

4. The method for correcting atmospheric refraction of stellar line of sight for optical satellite limb observation according to claim 1, characterized in that: Based on the atmospheric ellipsoid model, the star sight line is corrected for refraction of the atmospheric penetration layer to obtain a corrected first star sight line, including: Taking the star line of sight as the current star line of sight and the first atmospheric ellipsoid as the current atmospheric ellipsoid, calculate the intersection of the current star line of sight and the current atmospheric ellipsoid; if the two do not intersect, it is determined that the current star line of sight does not pass through the Earth's atmosphere, and no atmospheric refraction correction is required, and the calculation of the star's right ascension and declination is directly performed; otherwise, the periintersection point is used as the current intersection point, and the next step of calculation is performed; According to the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid, the atmospheric refraction coefficients of the current intersection point on the current layer and the previous layer of atmospheric ellipsoid are interpolated; Calculate the normal vector of the current atmospheric ellipsoid at the current intersection point : Where, are the major and minor axes of the atmospheric ellipsoid of the current layer, are the intersection coordinates, Indicates the number of the atmospheric ellipsoid; Calculate the incident angle of the current star's line of sight on the current atmospheric ellipsoid and refraction angle : Where, is the visual vector of the current star’s line of sight, and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Construct the current star's view vector , the apparent vector of the star after refraction and normal vector The coplanarity condition equation is: Where, , , ;in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction; Further solve the star's visual vector after refraction: Take the current intersection point as the starting point of the line of sight and the star view vector after refraction as the line of sight direction to obtain the new current star line of sight. Take the atmospheric ellipsoid of the next layer as the atmospheric ellipsoid of the current layer, and calculate the intersection point of the current star line of sight and the current atmospheric ellipsoid. If the two do not intersect, proceed to the next step of calculation. Otherwise, take the near intersection point as the current intersection point and re-enter the calculation of the atmospheric refraction coefficient of the current intersection point on the current and previous atmospheric ellipsoids.

5. The method for correcting atmospheric refraction of stellar line of sight for optical satellite limb observation according to claim 1, characterized in that: Based on the atmospheric ellipsoid model, performing atmospheric refraction correction on the corrected first star sight line to obtain a corrected second star sight line, including: The atmospheric ellipsoid of the previous layer of the current layer is used as the new atmospheric ellipsoid of the current layer, and the intersection point of the current star line of sight and the atmospheric ellipsoid of the current layer is calculated, and the far intersection point is used as the current intersection point; According to the atmospheric refraction coefficients of the regular grid points on the atmospheric ellipsoid, the atmospheric refraction coefficients of the current intersection point on the previous and current atmospheric ellipsoids are obtained by interpolation; Calculate the normal vector of the current atmospheric ellipsoid at the current intersection point : Where, is the intersection coordinate; Calculate the incident angle of the current star's line of sight on the current atmospheric ellipsoid and refraction angle : Where, is the visual vector of the current star line of sight; and are the atmospheric refraction coefficients of the previous and current atmospheric ellipsoids at the current intersection point respectively; Construct the current star's view vector , the apparent vector of the star after refraction and normal vector The coplanarity condition equation is: Where, , , ； in, is the normal vector The unit vector expression of is the current star's apparent vector The unit vector expression of is the apparent vector of the star after refraction; Further solve the star's visual vector after refraction: If the current atmospheric ellipsoid is the first atmospheric ellipsoid, then enter the calculation of the star's right ascension and declination. Otherwise, use the current intersection as the starting point of the line of sight and the star's visual vector after refraction as the line of sight direction to obtain a new current star line of sight. Use the previous atmospheric ellipsoid as the current atmospheric ellipsoid, and calculate the intersection of the current star line of sight and the current atmospheric ellipsoid. Then use the peri-intersection point as the current intersection, and re-enter the calculation of the atmospheric refraction coefficient of the current intersection on the previous and current atmospheric ellipsoids.

6. The method for correcting atmospheric refraction of stellar line of sight for optical satellite limb observation according to claim 1, characterized in that: The set of parameters of the earth's atmosphere includes the absolute temperature, relative humidity, atmospheric pressure and geopotential height of the earth's atmosphere.

7. An atmospheric refraction correction system for stellar line of sight for optical satellite limb observation, characterized in that: include: A construction module, used for constructing an atmospheric ellipsoid model according to a set of earth atmosphere parameters and earth ellipsoid parameters; The first calculation module is used to calculate the star line of sight based on the satellite orbit, attitude measurement value, image imaging time, star image plane coordinates and satellite camera parameters; A first correction module is configured to perform atmospheric refraction correction on the star sight line based on the atmospheric ellipsoid model to obtain a corrected first star sight line; A second correction module is configured to perform atmospheric refraction correction on the corrected first star sight line based on the atmospheric ellipsoid model to obtain a corrected second star sight line; The second calculation module is used to calculate the right ascension and declination of the star using the corrected second star sight line.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the atmospheric refraction correction method for stellar line of sight in optical satellite limb observation is implemented as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for correcting atmospheric refraction of a star's line of sight for optical satellite limb observation according to any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method for correcting atmospheric refraction of a star's line of sight for optical satellite limb observation according to any one of claims 1 to 6 is implemented.

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