Method and system for atmospheric refraction correction of optical satellite geometric model

Abstract

The present application belongs to the technical field of optical remote sensing, and discloses a method and system for atmospheric refraction correction of an optical satellite geometric model. First, satellite position information and atmospheric refractive index information are obtained, then the position information of light reaching the ground after atmospheric refraction correction is calculated according to the original rational polynomial model, satellite position information and atmospheric refractive index information, after that, the virtual three-dimensional grid points are re-established in combination with the position information of light reaching the ground after atmospheric refraction correction, and the coefficients of the rational polynomial model after atmospheric refraction correction are solved, finally, the coefficients of the rational polynomial model after atmospheric refraction correction are applied to the original rational polynomial model to obtain the rational polynomial model after atmospheric refraction correction. The present application can use the rational polynomial model after atmospheric refraction correction to perform geometric positioning of optical satellite images. The present application takes into account the influencing factors of atmospheric refraction, and can effectively improve the geometric positioning accuracy of optical satellite images.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical remote sensing, and more particularly relates to an optical satellite geometric model atmospheric refraction correction method and system. BACKGROUND

[0002] Optical satellite imaging plays an important role in obtaining ground information, but the imaging process is affected by factors such as atmospheric refraction, resulting in image geometric positioning errors. However, in existing optical remote sensing research, there are few related schemes considering atmospheric refraction. How to consider the influence factors of atmospheric refraction and then realize the atmospheric refraction correction of the optical satellite geometric model is a technical problem that needs to be solved in the field. SUMMARY

[0003] The present application provides an optical satellite geometric model atmospheric refraction correction method and system, which solves the problem of large image geometric positioning error caused by not considering the influence of atmospheric refraction in the existing optical satellite imaging.

[0004] The present application provides an optical satellite geometric model atmospheric refraction correction method, comprising the following steps:

[0005] Step 1, obtaining satellite position information and atmospheric refraction rate information; according to the original rational polynomial model, the satellite position information and the atmospheric refraction rate information, the position information of the light reaching the ground after atmospheric refraction correction is calculated;

[0006] Step 2, combining the position information of the light reaching the ground after atmospheric refraction correction, re-establishing a virtual three-dimensional grid point, and solving the coefficients of the rational polynomial model after atmospheric refraction correction; applying the coefficients of the rational polynomial model after atmospheric refraction correction to the original rational polynomial model to obtain the rational polynomial model after atmospheric refraction correction.

[0007] Preferably, the optical satellite geometric model atmospheric refraction correction method further comprises: step 3, using the rational polynomial model after atmospheric refraction correction to perform geometric positioning of optical satellite images.

[0008] Preferably, the satellite position information is obtained by the following method:

[0009] For optical satellite linear array push-broom imaging, one row of image corresponds to one satellite position, a plurality of virtual elevation planes are established by selecting a plurality of image points in a row of image, and the original rational polynomial model is used for calculation, so that the light passing through each image point intersects with the plurality of virtual elevation planes, and all the light rays in this row intersect at a point, and this intersection point corresponds to the satellite position corresponding to the row of image.

[0010] Preferably, for a certain image point (x i ,yi ), by the light rays of the image point intersecting a certain virtual elevation plane h j on the object side point (X ij , Y ij , Z ij ), i = 1, …, m, j = 1, …, n, m is the total number of image points on the kth row image, and n is the total number of virtual elevation planes;

[0011] A plurality of light rays passing through a plurality of image points on the kth row image intersect at the satellite position (X k , Y k , Z k );

[0012] For each object side point (X ij , Y ij , Z ij ), the following two linear equations are listed:

[0013] Y ij - Y k = K iy × (X ij - X k )

[0014] Z ij - Z k = K iz × (X ij - X k )

[0015] The initial values of the two slopes K iy , K iz in the above two linear equations are respectively:

[0016] K iy = (Y i1 - Y i2 ) / (X i1 - X i2 )

[0017] K iz = (Z i1 - Z i2 ) / (X i1 - X i2 )

[0018] For m x n points, 2m x n equations are listed, and the satellite position (X k , Y k , Z k ) corresponding to the kth row image is obtained by using the least square method.

[0019] Preferably, the atmospheric parameter information is collected, the atmospheric refractive index at the target position at the target time is calculated based on the atmospheric parameter information, and the atmospheric refractive index information includes atmospheric refractive indexes at multiple positions at the target time; and the atmospheric parameter information includes data corresponding to multiple parameters of atmospheric temperature, atmospheric pressure and atmospheric humidity.

[0020] Preferably, the atmospheric refractive index is calculated by using the following formula:

[0021] n = 1 + N / 10 6

[0022]

[0023] e = RH x e s

[0024]

[0025] In the formula, n represents the atmospheric refractive index, N represents the refractive index deviation, P represents the atmospheric pressure corresponding to the target height layer grid point; T represents the absolute temperature corresponding to the target height layer grid point, in units of Kelvin; e represents the water vapor partial pressure, RH represents the atmospheric relative humidity corresponding to the target height layer grid point, e s represents the saturated water vapor pressure; T d represents the dew point temperature, in units of Celsius.

[0026] Preferably, for a certain image point (x, y) and a certain virtual elevation plane h, the corresponding ground point coordinates (X, Y, Z) are calculated by using the original rational polynomial model and the atmospheric refractive index information;

[0027] The atmospheric refraction correction is performed in combination with the calculated ground point coordinates, the satellite position information and the atmospheric refractive index information, the light direction is processed, the position of the light ray after passing through the multi-layer atmosphere is calculated, and the virtual three-dimensional grid point is re-established.

[0028] Preferably, when the atmospheric refraction correction is performed, the satellite position corresponding to the image row where the image point is located is solved and recorded as (X0, Y0, Z0), the initial light direction is determined by using the satellite position (X0, Y0, Z0) and the ground point coordinates (X, Y, Z), the included angle between the initial light ray and the normal line of the earth is calculated, and the initial incident angle is calculated.

[0029] According to the Fresnel law, in combination with the satellite height corresponding to the image row where the image point is located, the atmospheric refractive index information and the initial incident angle, the refraction angle of the light ray when passing through a preset interval distance to a certain target height from the ground is calculated, and the propagation direction of the light ray is determined based on the calculated refraction angle.

[0030] The above process is repeated multiple times to repeatedly lower the light until the light reaches the ground, and the position (newLon, newLat) of the light when reaching the ground after refraction by the multi-layer atmosphere is calculated.

[0031] Preferably, the initial light direction is represented as (X-X0, Y-Y0, Z-Z0) ;

[0032] The re-established virtual three-dimensional grid point is represented as (x, y, h, newLon, newLat), and the re-established virtual three-dimensional grid point is used as a control point to solve the coefficients of the atmospheric refraction-corrected rational polynomial model.

[0033] In another aspect, the present application provides an optical satellite geometric model atmospheric refraction correction system, comprising:

[0034] An information acquisition module is configured to acquire satellite position information and atmospheric refraction index information;

[0035] A ground position calculation module is configured to calculate the position information of the light when reaching the ground after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction index information;

[0036] A solving module is configured to re-establish a virtual three-dimensional grid point in combination with the position information of the light when reaching the ground after atmospheric refraction correction, and solve the coefficients of the atmospheric refraction-corrected rational polynomial model;

[0037] A model correction module is configured to apply the coefficients of the atmospheric refraction-corrected rational polynomial model to the original rational polynomial model to obtain an atmospheric refraction-corrected rational polynomial model.

[0038] The optical satellite geometric model atmospheric refraction correction system is configured to perform the steps of the optical satellite geometric model atmospheric refraction correction method as described above.

[0039] One or more technical solutions provided in the present application have at least the following technical effects or advantages:

[0040] The present application firstly acquires satellite position information and atmospheric refraction index information, then calculates the position information of light rays reaching the ground after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction index information, then re-establishes virtual three-dimensional grid points in combination with the position information of light rays reaching the ground after atmospheric refraction correction, solves the coefficients of the rational polynomial model after atmospheric refraction correction, and finally applies the coefficients of the rational polynomial model after atmospheric refraction correction to the original rational polynomial model to obtain the rational polynomial model after atmospheric refraction correction, that is, the coefficients of the original rational polynomial model are replaced by the coefficients of the rational polynomial model after atmospheric refraction correction to obtain the geometric model after atmospheric refraction correction. On this basis, the present application can use the rational polynomial model after atmospheric refraction correction to perform geometric positioning of optical satellite images. That is, the present application proposes an atmospheric refraction correction method for a geometric model of an optical satellite based on a rational polynomial model and a corresponding system, considers the influencing factors of atmospheric refraction, acquires atmospheric parameters and applies them to the atmospheric refraction correction algorithm, and can effectively improve the geometric positioning accuracy of optical satellite images, especially the geometric positioning accuracy of optical satellite images with large angles. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A schematic diagram of calculating the position of a satellite in the optical satellite geometric model atmospheric refraction correction method provided by Embodiment 1 of the present application;

[0042] Figure 2 A schematic diagram of calculating the position of light rays reaching the ground after refraction by multiple layers of atmosphere in the optical satellite geometric model atmospheric refraction correction method provided by Embodiment 1 of the present application;

[0043] Figure 3 A positioning example comparison diagram before and after atmospheric refraction correction. DETAILED DESCRIPTION

[0044] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings in the specification and specific embodiments.

[0045] Embodiment 1:

[0046] Embodiment 1 provides an optical satellite geometric model atmospheric refraction correction method, mainly including the following steps:

[0047] Step 1, acquire satellite position information and atmospheric refraction index information; calculate the position information of light rays reaching the ground after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction index information;

[0048] Step 2, reestablish the virtual stereoscopic grid point in combination with the position information of the light reaching the ground after the atmospheric refraction correction, and solve the coefficients of the rational polynomial model after the atmospheric refraction correction; apply the coefficients of the rational polynomial model after the atmospheric refraction correction to the original rational polynomial model to obtain the rational polynomial model after the atmospheric refraction correction.

[0049] On the basis of the above scheme, the following can also be included:

[0050] Step 3, using the rational polynomial model after the atmospheric refraction correction to perform geometric positioning of the optical satellite image.

[0051] The present application will be described in detail below.

[0052] There are many specific ways to obtain satellite position information, and when satellite position information cannot be directly obtained, the present application provides a method for calculating satellite position. The present application can obtain satellite position information in the following way: for optical satellite linear array push-broom imaging, one row of image corresponds to one satellite position, a plurality of image points are selected on a certain row of image and a plurality of virtual elevation planes are established, the original rational polynomial model is calculated so that the light rays passing through each image point intersect with the plurality of virtual elevation planes, and all the light rays of this row intersect at one point, and this intersection point corresponds to the satellite position corresponding to the row of image.

[0053] Specifically, for a certain image point (x i ,y i ) on the kth row of image, the light ray passing through the image point intersects with a certain virtual elevation plane h j at the object side point (X ij , Y ij , Z ij ), i = 1, …, m, j = 1, …, n, m is the total number of image points on the kth row of image, and n is the total number of virtual elevation planes.

[0054] A plurality of light rays passing through a plurality of image points on the kth row of image intersect at the satellite position (X k , Y k , Z k );

[0055] The following two straight line equations are listed for each object side point (X ij , Y ij , Z ij ):

[0056] Y ij -Y k = K iy ×(X ij -X k )

[0057] Zij -Z k = K iz × (X ij -X k )

[0058] The initial values of the two slopes K iy , K iz in the above two linear equations are respectively:

[0059] K iy = (Y i1 -Y i2 ) / (X i1 -X i2 )

[0060] K iz = (Z i1 -Z i2 ) / (X i1 -X i2 )

[0061] For m x n points, 2m x n equations are listed, and the satellite position (X k , Y k , Z k ) corresponding to the kth row image is obtained by using the least square method.

[0062] Atmospheric parameter information is collected, for example, the atmospheric parameter information can be downloaded through the Internet, and then the atmospheric refractive index of the target position at the target time is calculated based on the atmospheric parameter information, and the atmospheric refractive index information includes the atmospheric refractive index of multiple positions at the target time; The atmospheric parameter information includes data corresponding to multiple parameters such as atmospheric temperature, atmospheric pressure and atmospheric humidity.

[0063] Specifically, the atmospheric refractive index can be calculated by the following formula:

[0064] n = 1 + N / 10 6

[0065]

[0066] e = RH x e s

[0067]

[0068] In the formula, n represents the atmospheric refractive index, N represents the refractive index deviation, P represents the atmospheric pressure corresponding to the target height layer grid point; T represents the absolute temperature corresponding to the target height layer grid point, in units of Kelvin; e represents the water vapor partial pressure, RH represents the atmospheric relative humidity corresponding to the target height layer grid point, e s represents the saturated water vapor pressure; T dThe dew point temperature is represented in degrees Celsius.

[0069] In the present application, for a certain image point (x, y) and a certain virtual elevation plane h, the corresponding ground point coordinates (X, Y, Z) are calculated by using the original rational polynomial model; the light ray direction is processed by combining the calculated ground point coordinates, the satellite position information and the atmospheric refraction information, and the position of the light ray after passing through the multi-layer atmosphere is calculated, and a virtual three-dimensional grid point is re-established.

[0070] In the present application, for a certain image point (x, y) and a certain virtual elevation plane h, the corresponding ground point coordinates (X, Y, Z) are calculated by using the original rational polynomial model; the light ray direction is processed by combining the calculated ground point coordinates, the satellite position information and the atmospheric refraction information, and the position of the light ray after passing through the multi-layer atmosphere is calculated, and a virtual three-dimensional grid point is re-established.

[0071] The re-established virtual three-dimensional grid point is represented as (x, y, h, newLon, newLat), and the re-established virtual three-dimensional grid point is used as a control point to solve the coefficients of the rational polynomial model after atmospheric refraction correction.

[0072] Embodiment 2 provides an optical satellite geometric model atmospheric refraction correction system, comprising:

[0073] The information acquisition module is configured to acquire satellite position information and atmospheric refraction information.

[0074] The information acquisition module is configured to acquire satellite position information and atmospheric refraction information.

[0075] The ground position calculation module is configured to obtain the position information of the light ray after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction information.

[0076] The solving module is configured to re-establish a virtual three-dimensional grid point in combination with the position information of the light ray after atmospheric refraction correction, and solve the coefficients of the rational polynomial model after atmospheric refraction correction.

[0077] A model correction module is configured to apply the coefficients of the atmospheric refraction corrected rational polynomial model to the original rational polynomial model to obtain the atmospheric refraction corrected rational polynomial model.

[0078] The optical satellite geometric model atmospheric refraction correction system is configured to perform the steps in the optical satellite geometric model atmospheric refraction correction method described in Embodiment 1.

[0079] Since the functions of the modules in the system provided in Embodiment 2 correspond to the steps in the method provided in Embodiment 1, Embodiment 2 can be understood by referring to the description of Embodiment 1, which will not be repeated here.

[0080] Based on the above description, the present application can be considered to mainly include the following four parts: (1) obtaining satellite position information, (2) obtaining atmospheric refraction information, (3) atmospheric refraction correction algorithm, and (4) recalculating a new atmospheric refraction corrected rational polynomial model.

[0081] In order to better understand the present application, the present application will be further described from the following four parts.

[0082] (1) Obtaining satellite position information.

[0083] Satellite position information can be obtained in various ways. Considering that satellite position information is often missing when a rational polynomial model is used, it is usually necessary to solve it by oneself, so a specific method for calculating satellite position is given herein.

[0084] Referring to Figure 1 For optical satellite linear array push-broom imaging, assuming that the satellite position (X k ,Y k ,Z k ) corresponding to the kth row of image, according to the rational polynomial model (RPM), the longitude and latitude coordinates of m image points on n elevation planes in the kth row of image can be calculated. Since the imaging light is a straight line, the light passing through each image point (x i ,y i ) intersects with each elevation plane h j at an object side point (X ij ,Y ij ,Z ij ), and these lights intersect with each other at the satellite point (X y ,Y y ,Z y ).(Wherein, i = 1, …, m, j = 1, …, n).

[0085] According to the above description, for each object side point (X ij ,Y ij ,Z ijTwo linear equations can be listed:

[0086] Y ij -Y k = K iy × (X ij -X k )

[0087] Z ij -Z k = K iz × (X ij -X k )

[0088] Where the slope K iy , K iz The initial value is:

[0089] K iy = (Y i1 -Y i2 ) / (X i1 -X i2 )

[0090] K iz = (Z i1 -Z i2 ) / (X i1 -X i2 )

[0091] For m x n points, 2m x n equations can be listed, and there are 3 + 2m unknowns (here, 3 refers to satellite coordinates X k , Y k and Z k , m refers to the slope K iy and K iz ). Therefore, as long as 2mn > 3 + 2m is met, it can be solved by the least square method. Generally, m = 5 and n = 3 are taken.

[0092] (2) Obtain atmospheric refractive index information.

[0093] The atmospheric refractive index information can be obtained in various ways, and the present application gives a method for calculating the atmospheric refractive index.

[0094] First, download atmospheric parameters such as temperature, pressure, humidity, etc. from the Internet, and then calculate the atmospheric refractive index based on the above parameters. Specifically, there are temperature, pressure, humidity and other data corresponding to each grid point of each earth height layer updated every few hours on the Internet every day. Using these data, the atmospheric refractive index of each grid point at the corresponding time and height can be calculated, and the atmospheric refractive index parameters at any time and any position in the earth's space can be obtained by numerical interpolation.

[0095] Atmospheric refractive index (n) is the ratio of the speed of light in the atmosphere to the speed of light in a vacuum. The calculation of atmospheric refractive index needs to consider the temperature, pressure and humidity of the atmosphere and other factors. Generally, the atmospheric refractive index is very close to 1, where: the atmospheric refractive index in a vacuum is 1, and the atmospheric refractive index of other atmospheres is greater than 1. Therefore, a small amount of refractive index minus 1 is commonly used to represent the refractive index deviation (N). The following provides a formula for calculating the refractive index deviation N.

[0096]

[0097] In the formula, N is the refractive index deviation, in units of parts per million (ppm); P is the air pressure, in units of hundred pascals (hPa); T is the absolute temperature, in units of Kelvin (K); and e is the water vapor partial pressure, in units of hundred pascals (hPa).

[0098] The specific calculation steps are as follows:

[0099] (1) Download atmospheric parameters from the Internet:

[0100] Air pressure P, temperature T, humidity RH (relative humidity).

[0101] (2) Calculate the water vapor partial pressure e:

[0102] The water vapor partial pressure can be calculated by the relative humidity RH and the saturated water vapor pressure e s The calculation is as follows:

[0103] e = RH × e s .

[0104] The saturated water vapor pressure e s can be estimated by the following formula:

[0105]

[0106] In the formula, T d is the dew point temperature (which can also be estimated by temperature and humidity).

[0107] (3) Calculate the refractive index deviation N:

[0108]

[0109] (4) Calculate the atmospheric refractive index n:

[0110] n = 1 + N / 10 6 .

[0111] A calculation example is given below.

[0112] Assume the following conditions: air pressure P = 1013.25 hPa (standard atmospheric pressure), temperature T = 20°C = 293.15 K, relative humidity RH = 50%.

[0113] (1) Calculate water vapor partial pressure e:

[0114]

[0115] e = 0.5 x 23.37 ≈ 11.685 hPa.

[0116] (2) Calculate the refractive index deviation N:

[0117]

[0118] (3) Calculate the atmospheric refractive index n:

[0119]

[0120] The atmospheric refractive index under given conditions can be calculated by the above method.

[0121] (3) Atmospheric refraction correction algorithm.

[0122] The present application proposes a new algorithm, which corrects the refraction of the image sight line direction according to the rational polynomial model and the atmospheric refractive index parameters of each layer of the earth ellipsoid.

[0123] Suppose the image point (x, y) and the virtual height plane h, using the original rational polynomial model and the atmospheric refractive index information, the corresponding ground point coordinates (X, Y, Z) can be obtained, and the satellite position (X0, Y0, Z0) of the point (corresponding to the line) can be obtained or calculated by the first step (i.e. using the content of the first part of the application). Therefore, the initial light direction is (X-X0, Y-Y0, Z-Z0), and the satellite height is h0, and the atmospheric refractive index n0 at this time and this place, and the angle between the light and the normal of the earth, i.e. the incident angle a0, is calculated.

[0124] Referring to Figure 2 After the light ray passes a distance Δh, it reaches a distance of h1 from the ground, and the atmospheric refractive index is n1. Assuming that the refractive index does not change within the distance Δh, according to the Fresnel law, the refraction angle b0 of the light ray at height h1 is calculated as follows: n0 x sin a0 = n1 x sin b0, b0 = asin (n0 x sin a0 / n1). Because n0 < n1, b0 < a0, the light ray slightly approaches the subsatellite point in the direction of the subsatellite point.

[0125] After a distance of Ah, the light reaches a height of h2 from the ground, and the atmospheric refraction index is n2. Assuming that the refraction index is constant in the distance of Ah, the refraction angle b1 of the light at the height of h2 is calculated according to the Fresnel law: n1×sina1=n2×sinb1, where the incident angle a1=b0, so b1=asin(n1×sina1 / n2). Because n1<n2, b1<a1, and the light is slightly closer to the nadir.

[0126] Thus, the position of the light on the ground can be calculated by repeated descending.

[0127] (4) Recalculating the rational polynomial model after new atmospheric refraction correction.

[0128] Further processing the light direction using the original rational polynomial model and atmospheric refraction correction, re-establishing virtual three-dimensional grid control points, and recalculating the rational polynomial model after new atmospheric refraction correction.

[0129] Dividing the original image into regular grids (x, y), and establishing multiple virtual elevation planes h, calculating the initial light direction for each object point (Lon, Lat) on each elevation plane, and then through repeated descending, the position (newLon, newLat) on the ground after passing through multiple atmospheric refraction, thus obtaining a set of virtual three-dimensional grid control points: (x, y, h, newLon, newLat), so that the new rational polynomial model coefficients can be solved.

[0130] The atmospheric refraction correction method for the optical satellite geometric model provided by the application can obtain the coefficients of the rational polynomial model after atmospheric refraction correction. For example, the rational polynomial model coefficients before (i.e., original) and after atmospheric refraction correction are shown in Table 1.

[0131] Table 1 Rational polynomial model coefficients before and after atmospheric refraction correction

[0132]

[0133]

[0134]

[0135] Correspondingly, the positioning examples before and after atmospheric refraction correction are shown in Table 2. Figure 3 The upper left of Table 2 corresponds to the positioning example before atmospheric refraction correction, Figure 3 The upper right of Table 2 corresponds to the positioning example after atmospheric refraction correction, Figure 3 The upper right of Table 2 corresponds to the positioning example after atmospheric refraction correction, Figure 3Below is a partial list of Ground Control Points (GCPs), showing that the geometric positioning accuracy of the optical satellite imagery has been improved after atmospheric refraction correction.

[0136] In summary, this invention proposes an atmospheric refraction correction method and system for optical satellite geometric models. By taking into account the influencing factors of atmospheric refraction, atmospheric parameters are obtained and applied to the atmospheric refraction correction algorithm. The original rational polynomial model coefficients are replaced with new rational polynomial model coefficients, which can significantly reduce the impact of atmospheric refraction on the geometric positioning accuracy of optical satellite images and improve the geometric positioning accuracy of optical satellite images. This method is applicable to various remote sensing application scenarios.

[0137] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for atmospheric refraction correction of an optical satellite geometric model, characterized in that, The method comprises the following steps: Step 1, obtaining satellite position information and atmospheric refraction information; calculating the position information of light rays reaching the ground after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction information; Step 2, re-establishing virtual three-dimensional grid points in combination with the position information of the light rays reaching the ground after atmospheric refraction correction, and solving the coefficients of the rational polynomial model after atmospheric refraction correction; applying the coefficients of the rational polynomial model after atmospheric refraction correction to the original rational polynomial model to obtain the rational polynomial model after atmospheric refraction correction; Step 3, using the rational polynomial model after atmospheric refraction correction to perform geometric positioning of optical satellite images; The satellite position information is obtained by the following method: for optical satellite linear array push-broom imaging, one row of images corresponds to one satellite position, a plurality of image points are selected in a row of images and a plurality of virtual elevation planes are established, the original rational polynomial model is used for calculation, so that the light rays passing through each image point intersect with the plurality of virtual elevation planes, and all the light rays in the row intersect at one point, which corresponds to the satellite position corresponding to the row of images; For a certain image point x , y ) and a certain virtual elevation plane h , the corresponding ground point coordinates X , Y , Z ) are calculated by using the original rational polynomial model and the atmospheric refraction information; the atmospheric refraction correction is performed in combination with the calculated ground point coordinates, the satellite position information and the atmospheric refraction information, the light direction is processed, the position of the light after passing through the multi-layer atmospheric refraction and reaching the ground is calculated, and the virtual stereoscopic grid points are re-established.

2. The method for optical satellite geometry model atmospheric refraction correction according to claim 1, characterized in that, For the i-th row image, the total number of image points is k , , , and the total number of virtual elevation planes is h j , , , , i =1, …, m , j =1, …, n , m , k , n . The plurality of light rays intersecting at the satellite position on the plurality of picture points of the line image k , , , ); The following two linear equations are listed for each object point , , ) The two slopes in the above two linear equations , The initial values ​​are as follows: for m × n List 2 points. m × n The equation is solved using the least squares method to obtain the th equation. k Satellite positions corresponding to the line image ( , , ).

3. The method of claim 1, wherein the optical satellite geometry model atmospheric refraction correction is determined by: The atmospheric parameter information is collected, and the atmospheric refraction at the target position at the target time is calculated based on the atmospheric parameter information, the atmospheric refraction information includes the atmospheric refraction at a plurality of positions at the target time, and the atmospheric parameter information includes data corresponding to atmospheric temperature, atmospheric pressure and atmospheric humidity.

4. The method of claim 3, wherein the method further comprises: The atmospheric refraction is calculated by the following formula: wherein, n represents the atmospheric refractive index, N represents the refractive index deviation, P represents the atmospheric pressure corresponding to the target height layer grid point; T represents the absolute temperature corresponding to the target height layer grid point, in Kelvin; e represents the water vapor partial pressure, RH represents the atmospheric relative humidity corresponding to the target height layer grid point, represents the saturated water vapor pressure; represents the dew point temperature, in Celsius.

5. The method of claim 1, wherein the optical satellite geometry model atmospheric refraction correction is determined by: When performing atmospheric refraction correction, the satellite position corresponding to the row of the image where the image point is located is denoted as ( ). X 0, Y 0, Z 0), using satellite position ( X 0, Y 0, Z 0) and ground point coordinates ( X , Y , Z Determine the initial ray direction, calculate the angle between the initial ray and the Earth's normal, and use it as the initial angle of incidence; According to the Fresnel law, in combination with the satellite height corresponding to the row of images where the image point is located, the atmospheric refraction information and the initial incident angle, the refraction angle of the light rays reaching a target height from the ground after each passing through a preset interval distance is calculated, and the propagation direction of the light rays is determined based on the calculated refraction angle; The above process is repeated many times, and the light repeatedly descends until the light reaches the ground, and the position of the light when it reaches the ground after being refracted by the multi-layer atmosphere is calculated newLon , newLat ).

6. The method of claim 5, wherein the method further comprises: The initial light ray direction is represented as X - X 0, Y - Y 0, Z - Z 0); The reestablished virtual stereoscopic grid point is represented as (x, y, h) x , y , h , newLon , newLat ), and the reestablished virtual stereoscopic grid point is taken as a control point to solve the coefficients of the rational polynomial model after atmospheric refraction correction.

7. An optical satellite geometric model atmospheric refraction correction system characterized by, The method comprises the following steps: An information acquisition module is configured to acquire satellite position information and atmospheric refraction information; A ground position calculation module is configured to calculate the position information of light rays reaching the ground after atmospheric refraction correction according to the original rational polynomial model, the satellite position information and the atmospheric refraction information; A solving module is configured to re-establish virtual three-dimensional grid points in combination with the position information of the light rays reaching the ground after atmospheric refraction correction, and solve the coefficients of the rational polynomial model after atmospheric refraction correction; A model correction module is configured to apply the coefficients of the rational polynomial model after atmospheric refraction correction to the original rational polynomial model to obtain the rational polynomial model after atmospheric refraction correction; The optical satellite geometric model atmospheric refraction correction system is configured to perform the steps in the optical satellite geometric model atmospheric refraction correction method according to any one of claims 1-6.

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