Starlight refraction information calculation method and device based on two-stage fine light ray tracing

Abstract

The application relates to a starlight refraction information calculation method and device based on two-stage fine light ray tracing. According to a global three-dimensional atmospheric refraction index field, the method determines the refraction index distribution of all atmospheric layers in a starlight refraction propagation path, divides a vector two-layer atmosphere into multiple layers, calculates the refraction index of each fine layer, and then calculates the refraction angle change amount and the height change amount from the center of the earth of the starlight passing through the fine layer of the first starlight path and the second starlight path. The obtained refraction angle change amount is summed to obtain the total refraction angle of the starlight passing through the atmospheric layer. Compared with an empirical starlight atmospheric refraction model, the method can accurately simulate the refraction path of the starlight passing through the global atmospheric layer by using a two-stage fine light ray tracing method, avoids the simplification error caused by the empirical starlight atmospheric refraction model when simulating starlight refraction, and improves the accuracy of the starlight refraction angle and starlight refraction visual height and other refraction information.

Description

Technical Field

[0001] The present application relates to the field of astronomical navigation technology, and in particular to a method and device for calculating starlight refraction information based on two-stage fine ray tracing. Background Art

[0002] In autonomous navigation using starlight atmospheric refraction, information such as the starlight refraction angle and apparent altitude formed when starlight passes through the atmosphere is crucial. In the simulation of the starlight atmospheric simulation system, it is necessary to accurately calculate the refraction path of starlight through the atmosphere and obtain information such as the starlight refraction angle and apparent altitude for subsequent simulation. When solving the starlight atmospheric refraction navigation solution, the geometric constraint relationship between the apparent altitude of starlight refraction and the spacecraft position enables autonomous positioning of the spacecraft. To ensure the positioning accuracy of the starlight atmospheric refraction navigation system, it is necessary to ensure the accuracy of the spacecraft's acquisition of the apparent altitude of starlight refraction.

[0003] Typically, the starlight refraction angle and apparent altitude are calculated using an empirical atmospheric refraction model. This model simplifies the refraction of starlight through the atmosphere and uses the USSA1976 reference atmospheric model to describe the refraction process, without accounting for variations in global atmospheric parameters. Therefore, the accuracy of refraction information such as the starlight refraction angle and apparent altitude obtained using this empirical model cannot be guaranteed. Summary of the Invention

[0004] Based on this, it is necessary to provide a method and device for calculating starlight refraction information based on two-stage fine ray tracing, which can ensure the calculation accuracy of refraction information such as starlight refraction angle and refraction apparent height, in order to address the above technical problems.

[0005] A method for calculating starlight refraction information based on two-stage fine ray tracing, the method comprising:

[0006] Step 1: Based on the global three-dimensional atmospheric refractive index field, determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path.

[0007] Step 2: In k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer determines the refractive index of the fine layer; where, k and l All are integers greater than 0.

[0008] Step 3: Calculate the starlight zenith angle of the fine layer in the first segment of the starlight path based on the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere.

[0009] Step 4: According to the height of the fine layer, the starlight zenith angle and refractive index of the corresponding fine layer, k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs.

[0010] Step 5: Based on the starlight zenith angle, determine whether the first segment of the starlight path meets the minimum refraction cut height. If not, continue the process from step 3 to step 4 until the requirement is met. If so, determine the starlight refraction apparent altitude based on the starlight cut height and the refractive index at the starlight cut height.

[0011] Step 6: Repeat the process from Step 3 to Step 4, replacing the first segment of the starlight path with the second segment of the starlight path. Determine the change in the refraction angle of the starlight in the second segment of the starlight path as it passes through the fine layer and the change in the altitude from the center of the earth where the refraction occurs, until the starlight passes through the highest atmospheric layer.

[0012] Step 7: Determine the total refraction angle of starlight as it passes through the atmosphere based on the sum of the changes in the refraction angles of starlight passing through the fine layers in the first and second starlight paths.

[0013] In one embodiment, in k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer is determined as:

[0014]

[0015]

[0016] in, For the i The refractive index of the fine layer, For the i The height of the fine layer, , For the distance between each fine layer, and Respectively k+ 1st floor and k Layer height, and Respectively k+ 1st floor and k The refractive index of the atmosphere.

[0017] In one embodiment, the starlight zenith angle of the fine layer in the first segment of the starlight path is calculated based on the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere:

[0018]

[0019] in, The first star path i A finely layered zenith angle of starlight, is the height of the highest atmosphere, is the refractive index of the uppermost atmospheric layer, For the i The height of the fine layer, For the i The refractive index of a fine layer, is the zenith angle of starlight at the highest level of the atmosphere.

[0020] In one embodiment, the changes in the refraction angles of the starlight passing through the fine layers in the first segment of the starlight path in step 4 are:

[0021]

[0022]

[0023]

[0024]

[0025] in, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, and Respectively Layer and k The refractive index of the atmosphere, and Respectively k+ 1st floor and k Layer height, For the i The refractive index of the fine layer, is the conversion variable, The first segment of the starlight path i A finely layered zenith angle of starlight, For the i The height of the fine layer.

[0026] In one embodiment, the change in altitude from the center of the Earth where the starlight passes through the fine layer in the first segment of the starlight path occurs is:

[0027]

[0028] wherein, is the zenith angle of the starlight passing through the i-th fine layer in the first segment of the starlight path, i is the variation of the height from the center of the earth at which the fine layer refraction occurs.

[0029] In one of the embodiments, the constraint formula for determining whether the first segment of the starlight path satisfies the minimum refraction cut height is:

[0030]

[0031] wherein, is the zenith angle of the starlight passing through the i-th fine layer in the first segment of the starlight path, i is the zenith angle of the starlight passing through the i-th fine layer in the first segment of the starlight path, is the set threshold value.

[0032] In one of the embodiments, the starlight refraction apparent height is:

[0033]

[0034] wherein, is the starlight refraction apparent height, is the refraction index at the starlight cut height, is the radius of the earth.

[0035] In one of the embodiments, the total starlight refraction angle of the starlight passing through the atmosphere is determined according to the sum of the refraction angle variations of the starlight passing through the fine layers in the first segment of the starlight path and the second segment of the starlight path:

[0036]

[0037] wherein, R is the total starlight refraction angle of the starlight passing through the atmosphere, M and n2 are respectively the number of the atmospheric layers passed through by the two segments of the starlight path, N is the refraction angle variation of the starlight passing through the i-th fine layer in the first segment of the starlight path, is the refraction angle variation of the starlight passing through the i-th fine layer in the second segment of the starlight path. i i

[0038] A starlight refraction information calculation device based on two-segment fine ray tracing, the device comprising:

[0039] An atmospheric layer refraction index distribution determination module, configured to determine the refraction index distribution of all the atmospheric layers in the starlight refraction propagation path according to a global three-dimensional atmospheric refraction index field. ​​​​

[0040] Fine-grained refractive index determination module for the k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer determines the refractive index of the fine layer; where, k and l All are integers greater than 0.

[0041] The module for calculating the starlight zenith angle of the fine layer is used to calculate the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere.

[0042] The calculation module of the refraction angle change and the height change of the refraction point from the center of the earth is used to calculate the refraction angle change according to the height of the fine layer, the starlight zenith angle and refraction index of the corresponding fine layer, the first k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs.

[0043] The starlight refraction apparent altitude determination module is used to determine whether the first segment of the starlight path meets the minimum refraction tangent altitude based on the starlight zenith angle. If not, the refraction angle change and the height change from the center of the earth at which the refraction occurs calculation module and the starlight refraction apparent altitude determination module are repeatedly executed until the requirements are met; if so, the starlight refraction apparent altitude is determined based on the starlight tangent altitude and the refraction index at the starlight tangent altitude.

[0044] The second segment starlight path ray tracing module is used to repeatedly execute the refraction angle change and the change in height from the center of the earth at which the refraction occurs calculation module and the starlight refraction apparent height determination module, replace the first segment starlight path with the second segment starlight path, determine the refraction angle change and the height change from the center of the earth at which the refraction occurs in the second segment starlight path as the starlight passes through the fine layer, until the starlight passes through the highest atmospheric layer.

[0045] The module for determining the total refraction angle of starlight passing through the atmosphere is used to determine the total refraction angle of starlight passing through the atmosphere based on the sum of the refraction angle changes of starlight passing through fine layers in the first and second starlight paths.

[0046] The above-mentioned method and device for calculating starlight refraction information based on two-stage fine ray tracing determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path based on the global three-dimensional atmospheric refractive index field. The method then subdivides the space between the two atmospheric layers into multiple layers, calculates the refractive index of each fine layer, and then calculates the change in the refractive angle of the starlight passing through the fine layer and the change in the altitude from the center of the Earth at the point of refraction for the first and second starlight paths. The obtained refractive angle changes are summed to obtain the total refractive angle of the starlight passing through the atmosphere. Compared with the empirical starlight atmospheric refraction model, this method uses a two-stage fine ray tracing method to accurately simulate the refraction path of starlight through the global atmosphere, avoiding the simplification errors introduced by the empirical starlight atmospheric refraction model when simulating starlight refraction. It also improves the accuracy of refraction information such as the starlight refraction angle and the apparent altitude of the starlight refraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 1 is a flow chart of a method for calculating starlight refraction information based on two-stage fine ray tracing in one embodiment;

[0048] Figure 2 A flow chart of a two-stage fine ray tracing method for calculating starlight refraction information in one embodiment;

[0049] Figure 3 Graphs showing the results of calculating starlight refraction information using a two-stage fine ray tracing method in one embodiment, wherein (a) shows the calculation results of the starlight refraction angle, and (b) shows the calculation results of the starlight refraction apparent altitude;

[0050] Figure 4 1 is a structural block diagram of a device for calculating starlight refraction information based on two-stage fine ray tracing in one embodiment. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0052] In one embodiment, Figure 1 、 Figure 2 As shown, a method for calculating starlight refraction information based on two-stage fine ray tracing is provided. This method is suitable for autonomous navigation systems for starlight atmospheric refraction and can accurately obtain refraction information of starlight passing through the atmosphere, such as the starlight refraction angle and the starlight refraction apparent altitude. Taking a low-orbit spacecraft as an example, the method includes the following steps:

[0053] Step 1: Based on the global three-dimensional atmospheric refractive index field, determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path.

[0054] Specifically, based on the ERA5 global atmospheric reanalysis dataset released by the European Centre for Medium-Range Weather Forecasts, the global atmospheric refractive index field in the optical band was obtained, and the refractive index distribution of all atmospheric layers in the starlight refraction propagation path was determined based on the global atmospheric refractive index field.

[0055] Step 2: In k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer determines the refractive index of the fine layer; where, k and l All are integers greater than 0.

[0056] Specifically, the k+ 1st floor and k The atmosphere is divided into 10 layers, and the distance between each fine layer is 100m. The height of the fine layer is for:

[0057]

[0058] in, .

[0059] Step 3: Calculate the starlight zenith angle of the fine layer in the first segment of the starlight path based on the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere.

[0060] Specifically, at the highest altitude in the atmosphere , the refractive index of the highest atmospheric layer Under the condition of , calculate the starlight zenith angle of each fine layer in the first segment of the starlight path.

[0061] Step 4: According to the height of the fine layer, the starlight zenith angle and refractive index of the corresponding fine layer, k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs.

[0062] Step 5: Based on the starlight zenith angle, determine whether the first segment of the starlight path meets the minimum refraction cut height. If not, continue the process from step 3 to step 4 until the requirement is met. If so, determine the starlight refraction apparent altitude based on the starlight cut height and the refractive index at the starlight cut height.

[0063] Step 6: Repeat the process from Step 3 to Step 4, replacing the first segment of the starlight path with the second segment of the starlight path. Determine the change in the refraction angle of the starlight in the second segment of the starlight path as it passes through the fine layer and the change in the altitude from the center of the earth where the refraction occurs, until the starlight passes through the highest atmospheric layer.

[0064] Step 7: Determine the total refraction angle of starlight as it passes through the atmosphere based on the sum of the changes in the refraction angles of starlight passing through the fine layers in the first and second starlight paths.

[0065] In the above-mentioned method for calculating starlight refraction information based on two-stage fine ray tracing, the method determines the refractive index distribution of all atmospheric layers in the starlight refraction propagation path based on the global three-dimensional atmospheric refractive index field, subdivides the space between the two atmospheric layers into multiple layers, calculates the refractive index of each fine layer, and then calculates the change in the refractive angle of the starlight passing through the fine layer and the change in the altitude from the center of the Earth at the point of refraction for the first and second starlight paths. The obtained refractive angle changes are summed to obtain the total refractive angle of the starlight passing through the atmosphere. Compared with the empirical starlight atmospheric refraction model, this method, using two-stage fine ray tracing, can accurately simulate the refraction path of starlight passing through the global atmosphere, avoiding the simplification errors introduced by the empirical starlight atmospheric refraction model when simulating starlight refraction. It also improves the accuracy of refraction information such as the starlight refraction angle and the apparent altitude of the starlight refraction.

[0066] In one embodiment, step 2 includes: k+ 1st floor and k The atmosphere is divided into layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer is determined as:

[0067]

[0068]

[0069] in, For the i The refractive index of the fine layer, For the i The height of the fine layer, , For the distance between each fine layer, and Respectively k+ 1st floor and k Layer height, and Respectively k+ 1st floor and k The refractive index of the atmosphere.

[0070] In one embodiment, step 3 includes: calculating the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the uppermost atmosphere:

[0071]

[0072] in, The first star path i A finely layered zenith angle of starlight, is the height of the highest atmosphere, is the refractive index of the uppermost atmospheric layer, For the i The height of the fine layer, For the i The refractive index of a fine layer, is the zenith angle of starlight at the highest level of the atmosphere.

[0073] In one embodiment, the changes in the refraction angles of the starlight passing through the fine layers in the first segment of the starlight path in step 4 are:

[0074]

[0075]

[0076]

[0077]

[0078] in, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, and Respectively k+ 1st floor and k The refractive index of the atmosphere, and Respectively k+ 1st floor and k Layer height, For the i The refractive index of the fine layer, is the conversion variable, The first segment of the starlight path i A finely layered zenith angle of starlight, For the i The height of the fine layer.

[0079] In one embodiment, the change in height from the center of the Earth at the point where the starlight in the first segment of the starlight path passes through the fine layer of refraction occurs in step 4 is:

[0080]

[0081] in, The first segment of the starlight path is the starlight passing through the i The change in altitude from the center of the Earth where fine-grained refraction occurs.

[0082] In one embodiment, the constraint formula for determining whether the first segment of the starlight path satisfies the minimum refraction cut height in step 5 is:

[0083]

[0084] in, The first segment of the starlight path i A finely layered zenith angle of starlight, To set the threshold.

[0085] In one embodiment, the apparent altitude of starlight refraction is:

[0086]

[0087] in, is the apparent height of starlight refraction, Starlight cut height The refractive index at is the radius of the Earth.

[0088] In one embodiment, step 7 includes: determining the total refraction angle of starlight passing through the atmosphere based on the sum of the changes in the refraction angle of starlight passing through the fine layers in the first segment of the starlight path and the second segment of the starlight path:

[0089]

[0090] in, R is the total refraction angle of starlight as it passes through the atmosphere, M and N are the number of atmospheric layers that the two starlight paths pass through, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, The second segment of the starlight path is the starlight passing through the i The variation of refraction angle in fine layers.

[0091] It should be understood that although Figure 1The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0092] In a verification example, a low-orbit spacecraft is used as the simulation object, and the simulation start time is 31 Dec 2023 12:00:00.000 UTCG. The orbital elements of the low-orbit spacecraft are: semi-major axis ; eccentricity ; Orbital inclination ; Ascending node right ascension ; Pericenter angular distance True anomaly .

[0093] The results of using the two-stage fine ray tracing method to calculate the starlight refraction information are as follows Figure 3 As shown, (a) is the calculation result of the starlight refraction angle, and (b) is the calculation result of the starlight refraction apparent altitude.

[0094] In one embodiment, Figure 4 As shown, a starlight refraction information calculation device based on two-stage fine ray tracing is provided, comprising: a module for determining the refractive index distribution of atmospheric layers, a module for determining the refractive index of fine layers, a module for calculating the starlight zenith angle of fine layers, a module for calculating the change in refraction angle and the change in the height from the center of the earth at which the refraction occurs, a module for determining the apparent height of starlight refraction, a module for tracing the second segment of the starlight path, and a module for determining the total refraction angle of starlight as it passes through the atmospheric layers, wherein:

[0095] The atmospheric layer refractive index distribution determination module is used to determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path based on the global three-dimensional atmospheric refractive index field.

[0096] Fine-grained refractive index determination module for the k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer determines the refractive index of the fine layer; where, k andl All are integers greater than 0.

[0097] The module for calculating the starlight zenith angle of the fine layer is used to calculate the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere.

[0098] The calculation module of the refraction angle change and the height change of the refraction point from the center of the earth is used to calculate the refraction angle change according to the height of the fine layer, the starlight zenith angle and refraction index of the corresponding fine layer, the first k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs.

[0099] The starlight refraction apparent altitude determination module is used to determine whether the first segment of the starlight path meets the minimum refraction tangent altitude based on the starlight zenith angle. If not, the refraction angle change and the height change from the center of the earth at which the refraction occurs calculation module and the starlight refraction apparent altitude determination module are repeatedly executed until the requirements are met; if so, the starlight refraction apparent altitude is determined based on the starlight tangent altitude and the refraction index at the starlight tangent altitude.

[0100] The second segment starlight path ray tracing module is used to repeatedly execute the refraction angle change and the change in height from the center of the earth at which the refraction occurs calculation module and the starlight refraction apparent height determination module, replace the first segment starlight path with the second segment starlight path, determine the refraction angle change and the height change from the center of the earth at which the refraction occurs in the second segment starlight path as the starlight passes through the fine layer, until the starlight passes through the highest atmospheric layer.

[0101] The module for determining the total refraction angle of starlight passing through the atmosphere is used to determine the total refraction angle of starlight passing through the atmosphere based on the sum of the refraction angle changes of starlight passing through fine layers in the first and second starlight paths.

[0102] In one embodiment, the fine layered refractive index determination module is further configured to: k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer is determined as:

[0103]

[0104]

[0105] in, For thei The refractive index of the fine layer, For the i The height of the fine layer, , For the distance between each fine layer, and Respectively k+ 1st floor and k Layer height, and Respectively k+ 1st floor and k The refractive index of the atmosphere.

[0106] In one embodiment, the module for calculating the starlight zenith angle of the fine layer is further configured to calculate the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmospheric layer:

[0107]

[0108] in, The first starlight path i A finely layered zenith angle of starlight, is the height of the highest atmosphere, is the refractive index of the uppermost atmospheric layer, For the i The height of the fine layer, For the i The refractive index of a fine layer, is the zenith angle of starlight at the highest level of the atmosphere.

[0109] In one embodiment, the refraction angle change and the height change from the center of the earth at the refraction location calculation module are as follows:

[0110]

[0111]

[0112]

[0113]

[0114] in, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, and Respectively k+ 1st floor and kThe refractive index of the atmosphere, and Respectively k+ 1st floor and k Layer height, For the i The refractive index of the fine layer, is the conversion variable, The first segment of the starlight path i A finely layered zenith angle of starlight, For the i The height of the fine layer.

[0115] In one embodiment, in the calculation module for the change in refraction angle and the change in the height from the center of the earth at which the starlight passes through the fine layer in the first segment of the starlight path, the change in the height from the center of the earth at which the starlight passes through the fine layer is:

[0116]

[0117] in, The first segment of the starlight path is the starlight passing through the i The change in altitude from the center of the Earth where fine-grained refraction occurs.

[0118] In one embodiment, the constraint formula used in the starlight refraction apparent altitude determination module to determine whether the first segment of the starlight path meets the minimum refraction tangent altitude is:

[0119]

[0120] in, The first segment of the starlight path i A finely layered zenith angle of starlight, To set the threshold.

[0121] In one embodiment, the apparent altitude of starlight refraction is:

[0122]

[0123] in, is the apparent height of starlight refraction, Starlight cut height The refractive index at is the radius of the Earth.

[0124] In one embodiment, the module for determining the total refraction angle of starlight passing through the atmosphere is further configured to determine the total refraction angle of starlight passing through the atmosphere based on the sum of the changes in the refraction angles of starlight passing through fine layers in the first and second segments of the starlight path:

[0125]

[0126] in, R is the total refraction angle of starlight as it passes through the atmosphere, M and N are the number of atmospheric layers that the two starlight paths pass through, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, The second segment of the starlight path is the starlight passing through the i The variation of refraction angle in fine layers.

[0127] The specific limitations of the device for calculating starlight refraction information based on two-stage fine ray tracing can be found in the limitations of the method for calculating starlight refraction information based on two-stage fine ray tracing described above and will not be further elaborated here. Each module in the device for calculating starlight refraction information based on two-stage fine ray tracing can be implemented in whole or in part via software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a computer device memory in software form, allowing the processor to call and execute the corresponding operations of each module.

[0128] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for calculating starlight refraction information based on two-stage fine ray tracing, characterized in that: The method comprises: Step 1: Based on the global three-dimensional atmospheric refractive index field, determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path; Step 2: In k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer determines the refractive index of the fine layer; where, k and l All are integers greater than 0; Step 3: Calculate the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmospheric layer; Step 4: According to the height of the fine layer, the starlight zenith angle and refractive index of the corresponding fine layer, k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs; Step 5: Determine whether the first segment of the starlight path meets the minimum refraction cut height based on the starlight zenith angle. If not, continue the process from step 3 to step 4 until the requirement is met. If so, determine the starlight refraction apparent height based on the starlight cut height and the refractive index at the starlight cut height. Step 6: Repeat steps 3 and 4, replacing the first segment of the starlight path with the second segment. Determine the change in the refraction angle of the starlight as it passes through the finer layers and the change in the altitude from the center of the Earth where the refraction occurs, until the starlight passes through the highest atmospheric layer. Step 7: Determine the total refraction angle of starlight as it passes through the atmosphere based on the sum of the changes in the refraction angles of starlight passing through the fine layers in the first and second starlight paths.

2. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: In the k+ 1st floor and k The atmosphere is divided into l layer, according to the height of each fine layer and the k+ 1st floor and k The refractive index of the layer is determined as: in, For the i The refractive index of the fine layer, For the i The height of the fine layer, , For the distance between each fine layer, and Respectively k+ 1st floor and k Layer height, 、 Respectively k+ 1st floor and k The refractive index of the atmosphere.

3. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: According to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmosphere, the starlight zenith angle of the fine layer in the first segment of the starlight path is calculated as: in, The first star path i A finely layered zenith angle of starlight, is the height of the highest atmosphere, is the refractive index of the uppermost atmospheric layer, For the i The height of the fine layer, For the i The refractive index of a fine layer, is the zenith angle of starlight at the highest level of the atmosphere.

4. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: The changes in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path in step 4 are: in, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, and Respectively k+ 1st floor and k The refractive index of the atmosphere, and Respectively k+ 1st floor and k Layer height, For the i The refractive index of the fine layer, is the conversion variable, The first segment of the starlight path i A finely layered zenith angle of starlight, For the i The height of the fine layer.

5. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 4, characterized in that: In the first segment of the starlight path, the change in height from the center of the earth where the starlight passes through the fine layer of refraction occurs is: in, The first segment of the starlight path is the starlight passing through the i The change in altitude from the center of the Earth where fine-grained refraction occurs.

6. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: The constraint formula used to determine whether the first segment of the starlight path meets the minimum refraction cut height is: in, The first segment of the starlight path i A finely layered zenith angle of starlight, To set the threshold.

7. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: The apparent height of starlight refraction is: in, is the apparent height of starlight refraction, Starlight cut height The refractive index at is the radius of the Earth.

8. The method for calculating starlight refraction information based on two-stage fine ray tracing according to claim 1, characterized in that: Based on the sum of the changes in the refraction angle of starlight passing through the fine layers in the first and second segments of the starlight path, the total refraction angle of starlight passing through the atmosphere is determined to be: in, R is the total refraction angle of starlight as it passes through the atmosphere, M and N are the number of atmospheric layers that the two starlight paths pass through, The first segment of the starlight path is the starlight passing through the i The variation of refraction angle of fine layering, The second segment of the starlight path is the starlight passing through the i The variation of refraction angle in fine layers.

9. A device for calculating starlight refraction information based on two-stage fine ray tracing, characterized in that: The device comprises: The atmospheric layer refractive index distribution determination module is used to determine the refractive index distribution of all atmospheric layers in the starlight refraction propagation path based on the global three-dimensional atmospheric refractive index field; Fine-grained refractive index determination module for the Layer and k The atmosphere is divided into l layer, according to the height of each fine layer and the Layer and k The refractive index of the layer determines the refractive index of the fine layer; where, k and l All are integers greater than 0; A module for calculating the starlight zenith angle of a fine layer, configured to calculate the starlight zenith angle of the fine layer in the first segment of the starlight path according to the height of the fine layer, the refractive index of the corresponding fine layer, and the height and refractive index of the highest atmospheric layer; The calculation module of the refraction angle change and the height change of the refraction occurrence point from the center of the earth is used to calculate the refraction angle change according to the height of the fine layer, the starlight zenith angle and refraction index of the corresponding fine layer, the first k+ 1st floor and k The height and refractive index of the layer are used to calculate the change in the refraction angle of the starlight passing through the fine layer in the first segment of the starlight path and the change in the height from the center of the earth where the refraction occurs; a starlight refraction apparent altitude determination module, configured to determine whether the first segment of the starlight path meets the minimum refraction tangent altitude based on the starlight zenith angle; if not, repeatedly executing the refraction angle change and refraction height change calculation modules and the starlight refraction apparent altitude determination module until the requirements are met; if so, determining the starlight refraction apparent altitude based on the starlight tangent altitude and the refractive index at the starlight tangent altitude; A second segment starlight path ray tracing module is used to repeatedly execute the refraction angle change and refraction point altitude change calculation module and the starlight refraction apparent altitude determination module, replacing the first segment starlight path with the second segment starlight path, and determining the refraction angle change and refraction point altitude change from the center of the earth as the starlight passes through fine layers in the second segment starlight path until the starlight passes through the highest atmospheric layer; The module for determining the total refraction angle of starlight passing through the atmosphere is used to determine the total refraction angle of starlight passing through the atmosphere based on the sum of the refraction angle changes of starlight passing through fine layers in the first and second starlight paths.

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