On-satellite on-orbit compensation method for earth observation sight angle of optical remote sensing satellite

Abstract

The invention provides an on-satellite on-orbit compensation method for an earth observation sight angle of an optical remote sensing satellite. The method comprises the following steps: acquiring an atmospheric refractive index of an optical wave band; obtaining the partial derivative of the atmospheric refractive index to the pressure intensity and the partial derivative of the atmospheric refractive index to the temperature, and obtaining the calculation precision of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index to the pressure intensity and the partial derivative of the atmospheric refractive index to the temperature; carrying out adaptive layering on the atmosphere according to the calculation precision of the atmospheric refractive index model to obtain adaptive height layer distribution of the atmosphere; and on the basis of the atmospheric layer adaptive height layer distribution, acquiring the line-of-sight angle deviation of the optical remote sensing satellite for earth observation by using a ray tracing method, and compensating the line-of-sight angle of the optical remote sensing satellite for earth observation according to the line-of-sight angle deviation of the optical remote sensing satellite for earth observation. According to the invention, the technical problem that the earth observation sight angle compensation method in the prior art cannot satisfy on-satellite in-orbit real-time high-precision calculation can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of optical remote sensing satellites, and in particular to an on-orbit compensation method for an optical remote sensing satellite to observe a line of sight angle of the earth. Background Art

[0002] With the gradual development of satellite technology, optical remote sensing satellites are constantly pursuing higher resolution, higher positioning accuracy, faster dynamic response and on-orbit real-time processing capabilities. When high-resolution optical remote sensing satellites observe the earth, the incident light passes through the atmosphere with uneven density, resulting in line of sight angle deviation. The geometric positioning error caused by this atmospheric refraction error is far greater than one pixel, which seriously restricts the high-precision geometric positioning capability of optical remote sensing satellites.

[0003] In the prior art, in order to weaken the influence of atmospheric refraction on the geometric positioning of optical remote sensing satellites, the traditional method divides the atmosphere into equal intervals and evenly layers it, and uses the ray tracing method to calculate the line-of-sight angle deviation caused by atmospheric refraction, so as to achieve line-of-sight angle compensation for earth observation. To meet the high-precision requirements, the number of atmospheric height layers that need to be divided by this method continues to increase, and the demand for computing power is increasing. Due to the limited onboard resources, it is difficult to meet the real-time computing needs on the satellite.

[0004] Therefore, the existing technology cannot meet the demand for high-precision compensation of the Earth observation line of sight angle on orbit, and it is necessary to develop relevant algorithms that take into account both high precision and real-time performance and are suitable for real-time processing on board. Summary of the invention

[0005] The present invention provides an on-board on-orbit compensation method for an optical remote sensing satellite's earth observation sight line angle, which can solve the technical problem that the earth observation sight line angle compensation method in the prior art cannot satisfy the requirements of on-board on-orbit real-time high-precision calculation.

[0006] According to one aspect of the present invention, there is provided an on-orbit compensation method for an optical remote sensing satellite to observe the earth's line of sight angle, the method comprising:

[0007] Get the atmospheric refraction index in the optical band;

[0008] Obtain the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature, and obtain the calculation accuracy of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature;

[0009] Adaptively stratify the atmosphere according to the calculation accuracy of the atmospheric refractive index model to obtain the adaptive altitude layer distribution of the atmosphere;

[0010] Based on the adaptive altitude layer distribution of the atmosphere, the ray tracing method is used to obtain the line-of-sight angle deviation of the optical remote sensing satellite for earth observation, and the line-of-sight angle of the optical remote sensing satellite for earth observation is compensated according to the line-of-sight angle deviation of the optical remote sensing satellite for earth observation.

[0011] Preferably, the atmosphere is adaptively layered according to the calculation accuracy of the atmospheric refractive index model to obtain the adaptive altitude layer distribution of the atmosphere, including:

[0012] The atmosphere is evenly layered along the height direction according to the preset height, and the change of the atmospheric refractive index at each height layer is obtained;

[0013] The atmospheric refractive index changes of each altitude layer are accumulated in sequence from the highest altitude layer to the lowest altitude layer. After each accumulation, the current accumulated value is compared with the calculation accuracy of the atmospheric refractive index model. When the current accumulated value is less than the calculation accuracy of the atmospheric refractive index model, the next accumulation is continued; when the current accumulated value is greater than or equal to the calculation accuracy of the atmospheric refractive index model, the altitude corresponding to the start of accumulation to the current altitude is taken as an adaptive altitude layer, and the current accumulated value is cleared to zero before the next accumulation is performed until the atmospheric layer altitude reaches the altitude of the lowest altitude layer, thereby obtaining the atmospheric layer adaptive altitude layer distribution.

[0014] Preferably, obtaining the calculation accuracy of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature includes:

[0015] Compare the magnitude of the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature;

[0016] The larger value of the two is taken as the calculation accuracy of the atmospheric refractive index model.

[0017] Preferably, obtaining the line of sight angle deviation of the optical remote sensing satellite for earth observation by using the ray tracing method includes:

[0018] Obtain the initial incident angle of the observation light incident on the first adaptive height layer;

[0019] Obtain the incident angle and refraction angle of each adaptive height layer according to the initial incident angle;

[0020] According to the initial incident angle, the incident angle and the refraction angle of each adaptive altitude layer, the corresponding geocentric angle under the condition of atmospheric refraction is obtained;

[0021] The actual sight angle for earth observation is obtained according to the corresponding geocentric angle under the condition of atmospheric refraction;

[0022] The line of sight angle deviation of the optical remote sensing satellite for earth observation is obtained based on the actual line of sight angle of earth observation and the line of sight angle of earth observation with atmospheric refraction.

[0023] Preferably, the initial incident angle is obtained by the following formula:

[0024]

[0025] The incident angle of each adaptive altitude layer is obtained by the following formula:

[0026]

[0027] The refraction angle of each adaptive height layer is obtained by the following formula:

[0028]

[0029] The corresponding geocentric angle under atmospheric refraction is obtained by the following formula:

[0030]

[0031] The actual line of sight angle for earth observation is obtained by the following formula:

[0032]

[0033] The line of sight angle deviation caused by atmospheric refraction for earth observation is obtained by the following formula:

[0034] δ = β-γ;

[0035] Where i0 represents the initial incident angle, Re represents the radius of the earth, H represents the satellite altitude, β represents the line of sight angle for earth observation with atmospheric refraction, r0 represents the distance from the center of the earth to the initial adaptive altitude layer, i k-1 、i k They represent the incident angles of the light at the k-1th layer and the kth adaptive height layer, r k Indicates the distance from the center of the earth to the kth adaptive altitude layer, n k-1 、n k Respectively represent the refractive index of the k-1th layer and the kth adaptive height layer, θ k It represents the refraction angle of the light at the kth adaptive height layer. They represent the initial layer and the kth layer geocentric angles respectively under the condition of atmospheric refraction. It represents the geocentric angle corresponding to the atmospheric refraction, m represents the total number of adaptive altitude layers, γ represents the actual line of sight angle for earth observation, and δ represents the line of sight angle deviation caused by atmospheric refraction for earth observation.

[0036] Preferably, the atmospheric refractive index in the optical band is obtained by the following formula:

[0037]

[0038] Where N represents the atmospheric refractive index in the optical band, N gaxs 、N gws Represent the atmospheric refraction index caused by dry atmosphere and water vapor, ρ a , w They represent the dry air density and water vapor density under actual conditions, ρ axs They represent the dry air density under standard atmospheric pressure, ρ ws It indicates the water vapor density at a temperature of 20°C, a pressure of 1333 Pa, and a relative humidity of 1.

[0039] According to another aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the above methods when executing the computer program.

[0040] By applying the technical solution of the present invention, the atmosphere is adaptively stratified according to the calculation accuracy of the atmospheric refractive index model, and the atmospheric adaptive altitude layer distribution is obtained. On the basis of the atmospheric adaptive altitude layer distribution, the line of sight angle deviation of the optical remote sensing satellite for earth observation is obtained, thereby achieving high-precision compensation of the line of sight angle of the optical remote sensing satellite for earth observation, and the calculation time is greatly reduced, providing technical support for the realization of real-time on-orbit positioning on the satellite. In addition, compared with the traditional atmospheric stratification with equal intervals, under the condition of comparable uncontrolled geometric positioning accuracy of optical images, the method of this patent can greatly reduce the number of atmospheric stratifications and effectively improve the real-time performance of satellite on-orbit processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 A flowchart of an on-orbit compensation method for an optical remote sensing satellite to observe the earth's line of sight angle provided by an embodiment of the present invention is shown;

[0043] Figure 2 A schematic diagram of an optical remote sensing satellite observing the earth according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0047] like Figure 1 As shown, the present invention provides an on-orbit compensation method for an optical remote sensing satellite to observe the earth's line of sight angle, the method comprising:

[0048] S10, obtaining the atmospheric refractive index in the optical band;

[0049] S20, obtaining a partial derivative of the atmospheric refractive index with respect to pressure and a partial derivative of the atmospheric refractive index with respect to temperature, and obtaining a calculation accuracy of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature;

[0050] S30, adaptively stratifying the atmosphere according to the calculation accuracy of the atmospheric refractive index model to obtain an adaptive height layer distribution of the atmosphere;

[0051] S40. Based on the adaptive altitude layer distribution of the atmosphere, the line of sight angle deviation of the optical remote sensing satellite for earth observation is obtained by using the ray tracing method, and the line of sight angle of the optical remote sensing satellite for earth observation is compensated according to the line of sight angle deviation of the optical remote sensing satellite for earth observation.

[0052] The present invention adaptively stratifies the atmosphere according to the calculation accuracy of the atmospheric refractive index model, obtains the distribution of adaptive altitude layers of the atmosphere, and obtains the line of sight angle deviation of the optical remote sensing satellite for earth observation based on the distribution of adaptive altitude layers of the atmosphere, thereby realizing high-precision compensation of the line of sight angle of the optical remote sensing satellite for earth observation, greatly reducing the calculation time, and providing technical support for the realization of real-time on-orbit positioning on the satellite. In addition, compared with the traditional atmospheric stratification with equal intervals, under the condition of comparable uncontrolled geometric positioning accuracy of optical images, the method of this patent can greatly reduce the number of atmospheric stratifications and effectively improve the real-time performance of satellite on-orbit processing.

[0053] According to an embodiment of the present invention, in S10 of the present invention, according to the theoretical expression of Ciddor-Owens, the atmospheric refractive index of the optical band is obtained as follows:

[0054]

[0055] Where N represents the atmospheric refractive index in the optical band, N gaxs 、N gws Represent the atmospheric refraction index caused by dry atmosphere and water vapor, ρ a , w They represent the dry air density and water vapor density under actual conditions, ρ axs They represent the dry air density under standard atmospheric pressure, ρ ws It indicates the water vapor density at a temperature of 20°C, a pressure of 1333 Pa, and a relative humidity of 1.

[0056] In this embodiment, under standard atmospheric pressure, the atmospheric refractive index N caused by dry air is gaxs for:

[0057]

[0058] Where, k0 = 238.0185 μm -2 ,k1=5792105μm -2 ,k2=57.362μm -2 ,k3=167917μm -2 , λ is the wavelength in vacuum (unit: μm), χ cis the CO2 content in the atmosphere (unit: ppm, generally assuming χ c =375ppm).

[0059] At standard atmospheric pressure, the atmospheric refractive index N caused by water vapor gws for:

[0060]

[0061] Among them, ω0=295.235, ω1=2.6422μm 2 ,ω2=-0.032380μm 4 ,ω3=0.004028μm 6 .

[0062] In practical cases, the dry air density ρ a for:

[0063]

[0064] Where P is the actual pressure, M d =0.0289632kg·mol -1 is the molar mass of dry atmosphere, χ w =0 is relative humidity, R = 8.314510 J·mol -1 ·K -1 is the common gas constant; T = 273.15 + t is the absolute temperature under actual conditions, t is the Celsius temperature under actual conditions; Z is the compressibility factor under actual gas conditions, and the calculation formula is:

[0065]

[0066] in,

[0067] a0=1.58123×10 -6 K·Pa -1

[0068] a1=-2.9331×10 -8 Pa -1

[0069] a2=1.1043×10 -10 K -1 ·Pa -1

[0070] b0=5.707×10 -6 K·Pa -1

[0071] b1=-2.051×10 -8 Pa -1

[0072] c0=1.9898×10 -4 K·Pa -1

[0073] d0=1.83×10 -11 K 2 ·Pa -2

[0074] e0=-0.765×10 -8 K 2 ·Pa -2 .

[0075] At standard atmospheric pressure, the density of dry air is ρ axs for:

[0076]

[0077] in, is the absolute temperature under standard atmospheric pressure, P d =101325pa.

[0078] Similarly, the actual water vapor density ρ w for:

[0079]

[0080] Among them, M w =0.018015kg·mol -1 is the molar mass of water vapor, χ w =1 is relative humidity.

[0081] In T w =293.15K (ie t w =20℃), P w =1333Pa and χ w =1 water vapor density ρ ws The calculation formula is:

[0082]

[0083] in,

[0084] According to an embodiment of the present invention, based on the Ciddor-Owens atmospheric refractive index calculation model, it can be known that the atmospheric refractive index is affected by multiple factors such as wavelength, temperature, air pressure, humidity, CO2 content, etc., and the influence of a single factor on the atmospheric refractive index is further calculated under standard atmospheric environment conditions. The calculation process will not be repeated here.

[0085] Finally, it can be found that atmospheric pressure and temperature have a great influence on the atmospheric refractive index. Therefore, the present invention obtains the calculation accuracy of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature, specifically including:

[0086] S21. Compare the magnitudes of the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature;

[0087] S22. The larger value of the two is used as the calculation accuracy of the atmospheric refractive index model.

[0088] According to an embodiment of the present invention, in S30 of the present invention, the atmosphere is adaptively layered according to the calculation accuracy of the atmospheric refractive index model to obtain the adaptive altitude layer distribution of the atmosphere, including:

[0089] S31, uniformly stratifying the atmosphere along the height direction according to a preset height, and obtaining the change amount of the atmospheric refractive index of each height layer;

[0090] S32. Accumulate the atmospheric refractive index changes of each altitude layer in sequence from the highest altitude layer to the lowest altitude layer. After each accumulation, compare the current accumulated value with the calculation accuracy of the atmospheric refractive index model. When the current accumulated value is less than the calculation accuracy of the atmospheric refractive index model, continue to accumulate for the next time. When the current accumulated value is greater than or equal to the calculation accuracy of the atmospheric refractive index model, take the altitude corresponding to the start of accumulation to the current altitude as an adaptive altitude layer, and clear the current accumulated value before accumulating for the next time, until the altitude of the atmospheric layer reaches the altitude of the lowest altitude layer, thereby obtaining the atmospheric layer adaptive altitude layer distribution.

[0091] For example, assume that the atmosphere is 120 km high and the atmosphere is evenly layered at a minimum altitude of 50 m. Calculate the atmospheric refractive index N at each altitude layer. i And the change in atmospheric refractive index ΔN i Further iterative calculations are performed from the initial altitude of 120 km to calculate the cumulative value of the atmospheric refractive index change. like If the calculation accuracy ε of the atmospheric refractive index model is less than ε, the atmospheric refractive index change of the next altitude layer will continue to be accumulated; is greater than or equal to the calculation accuracy ε of the atmospheric refractive index model, and the current j-th layer height H j Set to the latest adaptive altitude layer H k , and Reset to 0 and continue the next iterative calculation until the atmosphere height is 0, thereby obtaining the adaptive altitude layer distribution of the atmosphere.

[0092] Assuming that each adaptive altitude layer obtained by the above method has the same atmospheric density, where the atmospheric density is dry atmospheric density or water vapor density, the light is refracted only at the interface of adjacent layers and follows Snell's refraction law. The ray tracing method is used to obtain the line of sight angle deviation of the optical remote sensing satellite for earth observation.

[0093] In this embodiment, if Figure 2 As shown, the electromagnetic signal of target P reaches satellite S in the form of a broken line, and the corresponding line of sight angle is γ; the satellite locates the target point P' according to the observed light, and the corresponding line of sight angle is β.

[0094] The specific calculation steps for obtaining the line of sight angle deviation of optical remote sensing satellite earth observation using ray tracing method are as follows:

[0095] S41. Calculate the initial incident angle and refraction angle

[0096] According to the sine law, the initial incident angle of the observation light incident on the first adaptive height layer is:

[0097]

[0098] When the line of sight enters the atmosphere, it is refracted, and the Snell formula gives:

[0099] n0 sin i0 = n1 sin θ1;

[0100] Where n0 is the vacuum refractive index, set to 1, then the initial refraction angle is:

[0101]

[0102] S42, calculate the incident angle and refraction angle of each adaptive height layer

[0103] The atmosphere is divided into m layers. Since each layer of the atmosphere is assumed to be uniform, the line of sight in each layer of the atmosphere is a straight line. According to the Bouquer formula:

[0104] r0n0 sin i0=r k n k sin i k =r m n m sin i m ;

[0105] Then the incident angle of each adaptive altitude layer is:

[0106]

[0107] The refraction angles of each adaptive altitude layer are:

[0108]

[0109] S43. Calculate the geocentric angle deviation caused by atmospheric refraction

[0110] According to the line of sight angle of the earth observation with atmospheric refraction, the corresponding geocentric angle without atmospheric refraction is obtained. The formula is as follows:

[0111]

[0112] According to the initial incident angle, the incident angle and the refraction angle of each adaptive altitude layer, the corresponding geocentric angle under atmospheric refraction is obtained. The formula is as follows:

[0113]

[0114] The geocentric angle deviation caused by atmospheric refraction is obtained based on the geocentric angle corresponding to the case without atmospheric refraction and the geocentric angle corresponding to the case with atmospheric refraction. The formula is as follows:

[0115]

[0116] S44. Calculate the line of sight angle deviation caused by atmospheric refraction in earth observation

[0117] Calculate the actual line of sight angle for earth observation according to the sine law:

[0118]

[0119] The line of sight angle deviation of the optical remote sensing satellite for earth observation is obtained based on the actual line of sight angle of earth observation and the line of sight angle of earth observation with atmospheric refraction. The formula is as follows:

[0120] δ = β-γ;

[0121] Where i0 represents the initial incident angle, Re represents the radius of the earth, H represents the satellite altitude, β represents the line of sight angle for earth observation with atmospheric refraction, r0 represents the distance from the center of the earth to the initial adaptive altitude layer, i k-1 、i k They represent the incident angles of the light at the k-1th layer and the kth adaptive height layer, r k Indicates the distance from the center of the earth to the kth adaptive altitude layer, n k-1 、n k Respectively represent the refractive index of the k-1th layer and the kth adaptive height layer, θ k It represents the refraction angle of the light at the kth adaptive height layer. They represent the initial layer and the kth layer geocentric angles respectively under the condition of atmospheric refraction. represents the geocentric angle corresponding to the atmospheric refraction, m represents the total number of adaptive altitude layers, γ represents the actual line of sight angle for earth observation, δ represents the line of sight angle deviation caused by atmospheric refraction for earth observation, θ1 represents the initial refraction angle, n1 represents the refractive index of the first adaptive altitude layer, represents the geocentric angle corresponding to the absence of atmospheric refraction, Represents the deviation of the geocentric angle caused by atmospheric refraction.

[0122] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the above methods when executing the computer program.

[0123] In summary, the present invention provides an on-board compensation method for the line-of-sight angle of an optical remote sensing satellite for earth observation, which adaptively stratifies the atmosphere according to the calculation accuracy of the atmospheric refractive index model to obtain an adaptive altitude layer distribution of the atmosphere, and obtains the line-of-sight angle deviation of the optical remote sensing satellite for earth observation based on the adaptive altitude layer distribution of the atmosphere, thereby achieving high-precision compensation of the line-of-sight angle of the optical remote sensing satellite for earth observation, greatly reducing the calculation time, and providing technical support for achieving on-board real-time positioning. In addition, compared with the traditional atmospheric stratification with equal intervals, under the condition that the uncontrolled geometric positioning accuracy of the optical image is equivalent, the method of this patent can greatly reduce the number of atmospheric stratifications and effectively improve the real-time performance of satellite on-orbit processing.

[0124] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0125] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0126] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0127] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An on-orbit compensation method for an optical remote sensing satellite's earth observation sight angle, characterized in that: The method comprises: Get the atmospheric refraction index in the optical band; Obtain the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature, and obtain the calculation accuracy of the atmospheric refractive index model according to the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature; Adaptively stratify the atmosphere according to the calculation accuracy of the atmospheric refractive index model to obtain the adaptive altitude layer distribution of the atmosphere; Based on the adaptive altitude layer distribution of the atmosphere, the ray tracing method is used to obtain the line-of-sight angle deviation of the optical remote sensing satellite for earth observation, and the line-of-sight angle of the optical remote sensing satellite for earth observation is compensated according to the line-of-sight angle deviation of the optical remote sensing satellite for earth observation.

2. The method according to claim 1, characterized in that According to the calculation accuracy of the atmospheric refractive index model, the atmosphere is adaptively layered, and the adaptive altitude layer distribution of the atmosphere is obtained, including: The atmosphere is evenly layered along the height direction according to the preset height, and the change of the atmospheric refractive index at each height layer is obtained; The atmospheric refractive index changes of each altitude layer are accumulated in sequence from the highest altitude layer to the lowest altitude layer. After each accumulation, the current accumulated value is compared with the calculation accuracy of the atmospheric refractive index model. When the current accumulated value is less than the calculation accuracy of the atmospheric refractive index model, the next accumulation is continued; when the current accumulated value is greater than or equal to the calculation accuracy of the atmospheric refractive index model, the altitude corresponding to the start of accumulation to the current altitude is taken as an adaptive altitude layer, and the current accumulated value is cleared to zero before the next accumulation is performed until the atmospheric layer altitude reaches the altitude of the lowest altitude layer, thereby obtaining the atmospheric layer adaptive altitude layer distribution.

3. The method according to claim 1, characterized in that The calculation accuracy of the atmospheric refractive index model obtained by the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature includes: Compare the magnitude of the partial derivative of the atmospheric refractive index with respect to pressure and the partial derivative of the atmospheric refractive index with respect to temperature; The larger value of the two is taken as the calculation accuracy of the atmospheric refractive index model.

4. The method according to claim 1, characterized in that: The line of sight angle deviation of optical remote sensing satellite earth observation obtained by ray tracing method includes: Obtain the initial incident angle of the observation light incident on the first adaptive height layer; Obtain the incident angle and refraction angle of each adaptive height layer according to the initial incident angle; According to the initial incident angle, the incident angle and the refraction angle of each adaptive altitude layer, the corresponding geocentric angle under the condition of atmospheric refraction is obtained; The actual sight angle for earth observation is obtained according to the corresponding geocentric angle under the condition of atmospheric refraction; The line of sight angle deviation of the optical remote sensing satellite for earth observation is obtained based on the actual line of sight angle of earth observation and the line of sight angle of earth observation with atmospheric refraction.

5. The method according to claim 1, characterized in that The initial incident angle is obtained by the following formula: The incident angle of each adaptive altitude layer is obtained by the following formula: The refraction angle of each adaptive height layer is obtained by the following formula: The corresponding geocentric angle under atmospheric refraction is obtained by the following formula: The actual line of sight angle for earth observation is obtained by the following formula: The line of sight angle deviation caused by atmospheric refraction for earth observation is obtained by the following formula: δ = β-γ; Where i0 represents the initial incident angle, Re represents the radius of the earth, H represents the satellite altitude, β represents the line of sight angle for earth observation with atmospheric refraction, r0 represents the distance from the center of the earth to the initial adaptive altitude layer, i k-1 、i k They represent the incident angles of the light at the k-1th layer and the kth adaptive height layer, r k Indicates the distance from the center of the earth to the kth adaptive altitude layer, n k-1 、n k Respectively represent the refractive index of the k-1th layer and the kth adaptive height layer, θ k It represents the refraction angle of the light at the kth adaptive height layer. They represent the initial layer and the kth layer geocentric angles respectively under the condition of atmospheric refraction. It represents the geocentric angle corresponding to the atmospheric refraction, m represents the total number of adaptive altitude layers, γ represents the actual line of sight angle for earth observation, and δ represents the line of sight angle deviation caused by atmospheric refraction for earth observation.

6. The method according to claim 1, characterized in that The atmospheric refractive index in the optical band is obtained by the following formula: Where N represents the atmospheric refractive index in the optical band, N gaxs 、N gws Represent the atmospheric refraction index caused by dry atmosphere and water vapor, ρ a , w They represent the dry air density and water vapor density under actual conditions, ρ axs They represent the dry air density under standard atmospheric pressure, ρ ws It indicates the water vapor density at a temperature of 20°C, a pressure of 1333 Pa, and a relative humidity of 1.

7. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

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