A calculation method for atomic oxygen or ultraviolet flux based on ray tracing

Abstract

The present invention provides a calculation method for atomic oxygen or ultraviolet flux based on ray tracing, which relates to the technical field of spacecraft simulation calculation. The calculation method includes: calculating the atomic oxygen flux influence parameter or ultraviolet flux influence parameter of the spacecraft at each point on the orbit according to the orbit parameters of the spacecraft; dividing the spacecraft surface into multiple polygon mesh units, and setting the initial value of atomic oxygen flux or ultraviolet flux for each of the polygon mesh units; calculating the increased value of atomic oxygen flux or ultraviolet flux for each of the polygon mesh units at each point on the spacecraft's motion orbit, and finally obtaining the cumulative value of atomic oxygen flux or ultraviolet flux. Compared with the prior art, the present invention can greatly improve the calculation time efficiency, reduce costs, provide verification data for the calculation results of the Monte Carlo simulation method, and provide an efficient technical means for the rapid screening of spacecraft surface coating materials, having obvious advantages and broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft simulation calculation, and in particular, to a calculation method for atomic oxygen or ultraviolet flux based on ray tracing. Background Art

[0002] During the in-orbit service of a spacecraft, its surface is exposed to an atomic oxygen environment and receives ultraviolet irradiation, and the protective coating material attached to the outer surface will be continuously eroded / pecked. The strength of the erosion / pecking effect depends on the magnitude of the atomic oxygen / ultraviolet irradiation flux and the selection of the spacecraft surface coating material. The atomic oxygen / ultraviolet irradiation flux depends on factors such as the flight altitude, flight orientation, atomic oxygen density, and ultraviolet irradiation intensity of the spacecraft. And the stronger the anti-erosion / pecking ability of the coating material, the higher its synthesis cost. When optimizing the spacecraft design, it is necessary to optimally select the surface coating material according to its design life. Using experimental research to select the optimal surface coating material is time-consuming and costly, and is not suitable for material selection. This requires the use of simulation software to calculate the atomic oxygen / ultraviolet flux at each location on the surface of the spacecraft according to the flight environment parameters of the spacecraft.

[0003] Currently, most simulation software uses the Monte Carlo simulation method to calculate the atomic oxygen / ultraviolet irradiation flux of each unit on the spacecraft surface. After each random experiment generates simulated particles and their velocities, it is necessary to enumerate each subdivision grid on the spacecraft surface, and determine the surface subdivision grid that the simulated particles first touch through calculation. This makes the computational complexity of this method grow superlinearly with the total number of surface subdivision grids of the spacecraft and linearly with the total number of random experiments, and the performance lacks scalability. In fact, when the Monte Carlo simulation has a medium-scale grid subdivision and a medium-sized total number of random experiments, it also requires a long time to wait for the flux calculation result. As a result, the response time of the calculation task is long, the user experience is poor, and it is easy to cause accidental interruption of the calculation, the computational time cost is large, resulting in a lack of technical means for the preliminary screening of coating materials in the spacecraft optimization design process, resulting in an extended design cycle, and restricting its application. Summary of the Invention

[0004] The problem solved by the present invention is at least one aspect of the long response time of the calculation task, poor user experience, easy accidental interruption of the calculation, large computational time cost, lack of technical means for the preliminary screening of coating materials in the spacecraft optimization design process, and extended design cycle in the prior art method of using Monte Carlo simulation to calculate the atomic oxygen / ultraviolet irradiation flux of each unit on the spacecraft surface.

[0005] To solve the above problems, the present invention provides a calculation method for atomic oxygen or ultraviolet flux based on ray tracing, including the following steps:

[0006] Step S1: Calculate the atomic oxygen flux influence parameter or ultraviolet flux influence parameter at each point on the orbit of the spacecraft according to the orbit parameters of the spacecraft.

[0007] Step S2: Divide the surface of the spacecraft into multiple polygon mesh cells, and set the initial atomic oxygen flux value or the initial ultraviolet flux value for each of the polygon mesh cells.

[0008] Step S3: Calculate the increase in atomic oxygen flux for each polygon mesh cell at each point on the spacecraft's motion orbit according to the motion direction, angle of the atomic oxygen particles relative to the spacecraft, and the atomic oxygen flux influence parameter, or calculate the increase in ultraviolet flux for each polygon mesh cell at each point on the spacecraft's motion orbit according to the motion direction, angle of the ultraviolet irradiation relative to the spacecraft, and the ultraviolet flux influence parameter.

[0009] Step S4: Obtain the cumulative atomic oxygen flux value for each polygon mesh cell on the surface of the spacecraft according to the initial atomic oxygen flux value and the increase in atomic oxygen flux, or obtain the cumulative ultraviolet flux value for each polygon mesh cell on the surface of the spacecraft according to the initial ultraviolet flux value and the increase in ultraviolet flux.

[0010] Preferably, in step S1, the atomic oxygen flux influence parameter includes the spacecraft's motion speed and atomic oxygen density.

[0011] Preferably, in step S1, the ultraviolet flux influence parameter includes the ultraviolet irradiation direction, the spacecraft's sun exposure factor, and the ultraviolet irradiation intensity.

[0012] Preferably, in step S3, the calculation of the increase in atomic oxygen flux for each polygon mesh cell at each point on the spacecraft's motion orbit according to the motion direction, angle of the atomic oxygen particles relative to the spacecraft, and the atomic oxygen flux influence parameter includes:

[0013] Step S31: Determine the shielding factor of the polygon mesh cell along the opposite direction of the spacecraft's motion speed according to the first calculation formula.

[0014] Step S32: Determine the cosine value of the angle between the normal vector of the polygon mesh cell and the opposite direction of the spacecraft's motion speed.

[0015] Step S33: Calculate the increase in atomic oxygen flux for each polygon mesh cell at each point on the spacecraft's motion orbit according to the atomic oxygen flux influence parameter, the cosine value of the angle between the normal vector of the polygon mesh cell and the opposite direction of the spacecraft's motion speed, and the shielding factor of the polygon mesh cell along the opposite direction of the spacecraft's motion speed.

[0016] Preferably, in step S31, the first calculation formula is: the shielding factor of the polygon mesh unit in the opposite direction of the spacecraft's motion speed = 1 - the number of first intersecting rays / the number of vertices of the polygon mesh unit, where the number of first intersecting rays is the number of intersections of the rays emitted from each vertex of the grid unit polygon in the opposite direction of the spacecraft's motion speed.

[0017] Preferably, in step S33, according to the atomic oxygen flux influence parameter, the cosine value of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed, and the shielding factor of the polygon mesh unit in the opposite direction of the spacecraft's motion speed, calculating the atomic oxygen flux increase value of each polygon mesh unit at each point on the spacecraft's motion orbit includes:

[0018] When the cosine value of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed is greater than 0, the atomic oxygen flux increase value of the polygon mesh unit at the orbit point is 0;

[0019] Otherwise, the atomic oxygen flux increase value is the product of the shielding factor of the polygon mesh unit in the opposite direction of the spacecraft's motion speed, the absolute value of the spacecraft's motion speed, the area of the grid unit polygon, the atomic oxygen density, and the absolute value of the cosine value of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed.

[0020] Preferably, in step S3, calculating the ultraviolet flux increase value of each polygon mesh unit at each point on the spacecraft's motion orbit according to the relative motion direction, angle of the ultraviolet irradiation with respect to the spacecraft, and the ultraviolet flux influence parameter includes:

[0021] Step S34, determining the shielding factor of the polygon mesh unit in the opposite direction of the ultraviolet irradiation according to the second calculation formula;

[0022] Step S35, determining the cosine value of the angle between the normal vector of the polygon mesh unit and the opposite direction of the ultraviolet irradiation;

[0023] Step S36, according to the ultraviolet flux influence parameter, the cosine value of the angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction, and the shielding factor of the polygon mesh unit in the opposite direction of the ultraviolet irradiation, calculating the ultraviolet flux increase value of each polygon mesh unit at each point on the spacecraft's motion orbit.

[0024] Preferably, in step S34, the second calculation formula is: the shielding factor of the polygon mesh unit in the opposite direction of the ultraviolet irradiation = 1 - the number of second intersecting rays / the number of vertices of the polygon mesh unit, where the number of second intersecting rays is the number of intersections of the rays emitted by each vertex of the mesh unit polygon in the opposite direction of the ultraviolet irradiation.

[0025] Preferably, in step S36, according to the ultraviolet flux influence parameter, the cosine value of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction, and the shielding factor of the polygon mesh unit in the opposite direction of the ultraviolet irradiation, calculate the increase in the ultraviolet flux of each polygon mesh unit at each point on the spacecraft motion orbit, including:

[0026] When the cosine value of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction is greater than 0 or the spacecraft sun exposure factor is 0, the increase in the ultraviolet flux of the polygon mesh unit at the orbit point is 0;

[0027] Otherwise, the increase in the ultraviolet flux is the product of the shielding factor of the polygon mesh unit in the opposite direction of the ultraviolet irradiation, the area of the mesh unit polygon, the ultraviolet irradiation intensity, and the absolute value of the cosine value of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction.

[0028] Preferably, in step S2, the initial value of the atomic oxygen flux or the initial value of the ultraviolet flux is 0.

[0029] The advantage of the calculation method of atomic oxygen or ultraviolet flux based on ray tracing according to the present invention compared with the prior art is that the high - efficiency approximate calculation method of atomic oxygen / ultraviolet flux based on ray tracing in this method has simple steps, is easy to implement, the operation process is transparent to users, the result is highly referential, and the ray tracing approximate calculation method proposed by the present invention can greatly improve the calculation time efficiency under the condition of slightly reduced calculation accuracy, reduce the cost of calculating, using and researching the atomic oxygen / ultraviolet irradiation flux on the spacecraft surface, provide verification data for the calculation results of the Monte Carlo simulation method, provide an efficient technical means for the rapid screening of spacecraft surface coating materials, and serve as a supporting technology for the teaching and demonstration of spacecraft optimization design simulation software, which has great significance. It has obvious advantages and broad application prospects in technical applications such as the promotion, teaching and demonstration of spacecraft optimization design and simulation software based on ablation / corrosion. Description of the Drawings

[0030] Figure 1 It is a flowchart of the calculation method of atomic oxygen or ultraviolet flux based on ray tracing in the embodiment of the present invention;

[0031] Figure 2Schematic diagram of the result of calculating atomic oxygen flux based on the Monte Carlo simulation method in the embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the result of calculating atomic oxygen flux based on ray tracing in the embodiment of the present invention;

[0033] Figure 4 Schematic diagram of the result of calculating ultraviolet flux based on the Monte Carlo simulation method in the embodiment of the present invention;

[0034] Figure 5 Schematic diagram of the result of calculating ultraviolet flux based on ray tracing in the embodiment of the present invention. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present application will be clearly and elaborately described below with reference to the accompanying drawings.

[0036] In the description of the embodiments of the present application, the description of the term "some embodiments" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0037] It should also be noted that in the description of the embodiments of the present application, the term "comprising" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or terminal device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the presence of additional identical elements in the process, method, article, or terminal device comprising the said elements.

[0038] As Figure 1 shown, the embodiment of the present invention provides a method for calculating atomic oxygen or ultraviolet flux based on ray tracing, including the following steps:

[0039] Step S1, calculate the atomic oxygen flux influence parameter or ultraviolet flux influence parameter of the spacecraft at each point on the orbit according to the orbit parameters of the spacecraft;

[0040] Step S2, divide the surface of the spacecraft into a plurality of polygon mesh units, and set the initial value of the atomic oxygen flux or the initial value of the ultraviolet flux for each of the polygon mesh units;

[0041] Step S3: Calculate the increment of atomic oxygen flux for each polygon mesh unit at each point on the spacecraft's motion orbit based on the motion direction, angle of the atomic oxygen particles relative to the spacecraft, and the atomic oxygen flux influence parameter, or calculate the increment of ultraviolet flux for each polygon mesh unit at each point on the spacecraft's motion orbit based on the motion direction, angle of the ultraviolet irradiation relative to the spacecraft, and the ultraviolet flux influence parameter;

[0042] Step S4: Obtain the cumulative atomic oxygen flux value for each polygon mesh unit on the spacecraft's surface based on the initial atomic oxygen flux value and the increment of atomic oxygen flux, or obtain the cumulative ultraviolet flux value for each polygon mesh unit on the spacecraft's surface based on the initial ultraviolet flux value and the increment of ultraviolet flux.

[0043] Thus, in this embodiment, when calculating the atomic oxygen flux, the ray tracing method is used to directly calculate the atomic oxygen flux of each subdivision mesh unit on the spacecraft's surface according to the motion direction and angle of the atomic oxygen particles relative to the spacecraft. Only the occlusion relationship of the surface mesh units in the motion direction is considered, the specular reflection and diffuse reflection effects of the atomic oxygen particles are ignored, and there is no need to simulate the generation of particles, achieving the purpose of greatly shortening the approximate calculation of the atomic oxygen flux. When calculating the ultraviolet flux, the ray tracing method is used to directly calculate the ultraviolet flux of each subdivision mesh unit on the spacecraft's surface according to the illumination direction relative to the spacecraft's motion direction and angle. Only the occlusion relationship of the surface mesh units to the illumination in the motion direction and the occlusion relationship of the spacecraft relative to the earth are considered, the specular reflection and diffuse reflection effects of the illumination are ignored, and there is no need to simulate the generation of particles, achieving the purpose of efficiently approximating the calculation of the ultraviolet irradiation flux.

[0044] In some embodiments, in step S1, the atomic oxygen flux influence parameter includes the spacecraft's motion speed vel and the atomic oxygen density density. Thus, the calculation of the atomic oxygen flux is accurate.

[0045] In some embodiments, in step S1, the ultraviolet flux influence parameter includes the ultraviolet irradiation direction dir, the spacecraft's sun exposure factor isShined, and the ultraviolet irradiation intensity strength. Thus, the calculation of the ultraviolet flux is accurate.

[0046] In some embodiments, in step S3, the calculation of the increment of atomic oxygen flux for each polygon mesh unit at each point on the spacecraft's motion orbit based on the motion direction, angle of the atomic oxygen particles relative to the spacecraft, and the atomic oxygen flux influence parameter includes:

[0047] Step S31: Determine the occlusion factor r of the polygon mesh unit along the opposite direction of the spacecraft's motion speed according to the first calculation formula o ;

[0048] Step S32, determine the cosine value cosα of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed;

[0049] Step S33, according to the atomic oxygen flux influence parameter, the cosine value cosα of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed, and the shielding factor r of the polygon mesh unit along the opposite direction of the spacecraft's motion speed o , calculate the increase value of the atomic oxygen flux of each polygon mesh unit at each point on the spacecraft's motion orbit. Thus, during the calculation process, the specular reflection and diffuse reflection effects of atomic oxygen particles are ignored and there is no need to simulate the generation of particles, achieving the purpose of greatly shortening the approximate calculation of the atomic oxygen flux.

[0050] In some embodiments, in step S31, the first calculation formula is: the shielding factor r of the polygon mesh unit along the opposite direction of the spacecraft's motion speed o = 1 - the number of first intersecting rays / the number of vertices of the polygon mesh unit, where the number of first intersecting rays is the number of intersections of the rays emitted along the opposite direction of the spacecraft's motion speed by each vertex of the polygon of the grid unit. Thus, examine whether the rays emitted along the opposite direction of the spacecraft's motion speed by each vertex of the polygon mesh unit intersect with the polygons of other grid units of the spacecraft to calculate the atomic oxygen flux.

[0051] In some embodiments, in step S33, according to the atomic oxygen flux influence parameter, the cosine value cosα of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed, and the shielding factor r of the polygon mesh unit along the opposite direction of the spacecraft's motion speed o , calculate the increase value of the atomic oxygen flux of each polygon mesh unit at each point on the spacecraft's motion orbit, including:

[0052] When the cosine value cosα of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed is greater than 0, the increase value of the atomic oxygen flux of the polygon mesh unit at the orbit point is 0;

[0053] Otherwise, the increase value of the atomic oxygen flux is the product of the shielding factor r of the polygon mesh unit along the opposite direction of the spacecraft's motion speed o , the absolute value of the spacecraft's motion speed vel, the area S of the polygon of the grid unit, the atomic oxygen density density, and the absolute value of the cosine value cosα of the angle between the normal vector of the polygon mesh unit and the opposite direction of the spacecraft's motion speed, that is, the increase value of the atomic oxygen flux is r o*|vel|*S*density*|cosα|. Thus, the calculation is simple.

[0054] In some embodiments, in step S3, calculating the increased value of the ultraviolet flux of each polygon mesh unit at each point of the spacecraft's motion orbit according to the motion direction, included angle of the ultraviolet irradiation relative to the spacecraft, and the ultraviolet flux influence parameter includes:

[0055] Step S34, determining the shielding factor r of the polygon mesh unit along the reverse direction of the ultraviolet irradiation according to the second calculation formula s ;

[0056] Step S35, determining the cosine value cosβ of the included angle between the normal vector of the polygon mesh unit and the reverse direction of the ultraviolet irradiation;

[0057] Step S36, according to the ultraviolet flux influence parameter, the cosine value cosβ of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction, and the shielding factor r of the polygon mesh unit along the reverse direction of the ultraviolet irradiation s , calculating the increased value of the ultraviolet flux of each polygon mesh unit at each point of the spacecraft's motion orbit. Thus, during the calculation process, the specular reflection and diffuse reflection effects of atomic oxygen particles are ignored and there is no need to simulate the generation of particles, achieving the purpose of greatly shortening the approximate calculation of the ultraviolet flux.

[0058] In some embodiments, in step S34, the second calculation formula is: the shielding factor r of the polygon mesh unit along the reverse direction of the ultraviolet irradiation s =1 - the number of second intersecting rays / the number of vertices of the polygon mesh unit, where the number of second intersecting rays is the number of intersections of the rays emitted along the reverse direction of the ultraviolet irradiation by each vertex of the polygon of the mesh unit. Thus, it is examined whether the rays emitted along the reverse direction of the ultraviolet irradiation by each vertex of the polygon mesh unit intersect with the polygons of other mesh units of the spacecraft to calculate the ultraviolet flux.

[0059] In some embodiments, in step S36, according to the ultraviolet flux influence parameter, the cosine value cosβ of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction, and the shielding factor r of the polygon mesh unit along the reverse direction of the ultraviolet irradiation s , calculating the increased value of the ultraviolet flux of each polygon mesh unit at each point of the spacecraft's motion orbit includes:

[0060] When the cosine value cosβ of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction is greater than 0 or the spacecraft sun exposure factor isShined is 0, the increased value of the ultraviolet flux of the polygon mesh unit at the orbital point is 0;

[0061] Otherwise, the increased value of the ultraviolet flux is the shielding factor r of the polygon mesh unit along the reverse direction of the ultraviolet irradiation s , the area S of the polygon of the grid cell, the ultraviolet irradiation intensity strength, and the product of the absolute value of the cosine value cosβ of the included angle between the normal vector of the polygon mesh unit and the ultraviolet irradiation direction, that is, the increased value of the ultraviolet flux is r s *S × strength × |cosβ|. Thus, the calculation is simple.

[0062] In some embodiments, in step S2, the initial value of the atomic oxygen flux or the initial value of the ultraviolet flux is 0. Thus, the calculation is convenient.

[0063] Therefore, the advantages of the calculation method of atomic oxygen or ultraviolet flux based on ray tracing in this embodiment compared with the prior art are that the steps of the efficient approximate calculation method of atomic oxygen / ultraviolet flux based on ray tracing in this method are simple, easy to implement, the operation process is transparent to users, the result reference is strong, and the ray tracing approximate calculation method proposed in this embodiment can greatly improve the calculation time efficiency under the condition of slightly reduced calculation accuracy, reduce the calculation, use and research costs of the atomic oxygen / ultraviolet irradiation flux on the spacecraft surface, provide verification data for the calculation results of the Monte Carlo simulation method, provide an efficient technical means for the rapid screening of spacecraft surface coating materials, and serve as the supporting technology for the teaching and demonstration of spacecraft optimization design simulation software, which has great significance. In the technical applications such as the popularization, teaching and demonstration of spacecraft optimization design and simulation software based on ablation / erosion, it has obvious advantages and broad application prospects.

[0064] Embodiment 1

[0065] This embodiment provides a calculation method of atomic oxygen flux based on ray tracing, including the following steps:

[0066] (1) Calculate the atomic oxygen flux influence parameters of the spacecraft at each point on the orbit according to the orbital parameters of the spacecraft, including the spacecraft motion speed vel and the atomic oxygen density density;

[0067] (2) Divide the spacecraft surface into multiple polygon mesh units, and set the initial value of the atomic oxygen flux of each polygon mesh unit to 0;

[0068] (3) Determine the occlusion factor r of the polygon mesh cell along the opposite direction of the spacecraft's motion velocity according to the first calculation formula. o ; and determine the cosine value cosα of the angle between the normal vector of the polygon mesh cell and the opposite direction of the spacecraft's motion velocity. When cosα > 0, the increased value of the atomic oxygen flux of the polygon mesh cell at the orbital point is 0; otherwise, the increased value of the atomic oxygen flux is r. o *|vel|*S*density*|cosα|, where S is the area of the polygon of the mesh cell. The first calculation formula is: r. o = 1 - the number of the first intersecting rays / the number of vertices of the polygon mesh cell. The number of the first intersecting rays is the number of intersections of the rays emitted from each vertex of the polygon of the mesh cell along the opposite direction of the spacecraft's motion velocity.

[0069] (4) Accumulate the increased values of the atomic oxygen flux of each polygon mesh cell at each point of the spacecraft's motion orbit to obtain the accumulated value of the atomic oxygen flux of each polygon mesh cell on the spacecraft surface and output it.

[0070] Embodiment 2

[0071] This embodiment provides a method for calculating the ultraviolet flux based on ray tracing, including the following steps:

[0072] (1) Calculate the ultraviolet flux influence parameters of the spacecraft at each point of the orbit according to the orbital parameters of the spacecraft, including the ultraviolet irradiation direction dir, the spacecraft sun exposure factor isShined, and the ultraviolet irradiation intensity strength.

[0073] (2) Divide the spacecraft surface into multiple polygon mesh cells, and set the initial value of the ultraviolet flux of each polygon mesh cell to 0.

[0074] (3) Determine the occlusion factor r of the polygon mesh cell along the opposite direction of the ultraviolet irradiation according to the second calculation formula. s , and determine the cosine value cosβ of the angle between the normal vector of the polygon mesh cell and the opposite direction of the ultraviolet irradiation. When cosβ > 0 or isShined = 0, the increased value of the ultraviolet flux of the polygon mesh cell at the orbital point is 0; otherwise, the increased value of the ultraviolet flux is r. s *S×strength×|cosβ|. Where S is the area of the polygon of the mesh cell. The second calculation formula is: r. s = 1 - the number of the second intersecting rays / the number of vertices of the polygon mesh cell. Where the number of the second intersecting rays is the number of intersections of the rays emitted from each vertex of the polygon of the mesh cell along the opposite direction of the ultraviolet irradiation.

[0075] (4) Accumulate the increased values of the ultraviolet fluxes of each of the polygon mesh cells at each point on the spacecraft motion orbit to obtain the accumulated values of the ultraviolet fluxes of each of the polygon mesh cells on the spacecraft surface and output them.

[0076] Embodiment 3

[0077] To verify the effectiveness of the calculation methods of atomic oxygen or ultraviolet flux based on ray tracing in Embodiment 1 and Embodiment 2, in this embodiment, the same grid density, number of particles, and number of particle reflections are used to perform Monte Carlo-based simulation calculations of atomic oxygen / ultraviolet flux for comparison. As Figures 2 - 5 shown, Figure 2 is a schematic diagram of the result of calculating the atomic oxygen flux based on the Monte Carlo simulation method in this embodiment, and the calculation time is 24.318. Figure 3 is a schematic diagram of the result of calculating the atomic oxygen flux based on ray tracing in Embodiment 1, and the calculation time is 3.451. Figure 4 is a schematic diagram of the result of calculating the ultraviolet flux based on the Monte Carlo simulation method in this embodiment, and the calculation time is 18.194. Figure 5 is a schematic diagram of the result of calculating the ultraviolet flux based on ray tracing in Embodiment 2, and the calculation time is 2.519. Among them, Figure 2 and Figure 3 in, the magnitude of the atomic oxygen flux is represented by the change in the depth of color. The darker the color, the greater the atomic oxygen flux. Figure 4 and Figure 5 in, the magnitude of the ultraviolet irradiation flux is represented by the change in the depth of color. The darker the color, the greater the ultraviolet irradiation flux. It can be seen from the figure that compared with the Monte Carlo-based atomic oxygen / ultraviolet flux simulation method in this embodiment, the calculation efficiency of the atomic oxygen or ultraviolet flux calculation methods based on ray tracing in Embodiment 1 and Embodiment 2 is greatly improved.

[0078] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A calculation method of atomic oxygen or ultraviolet flux based on ray tracing, characterized in that, It includes the following steps: Step S1, calculate the atomic oxygen flux influence parameter or ultraviolet flux influence parameter of the spacecraft at each point on the orbit according to the orbit parameters of the spacecraft, where the atomic oxygen flux influence parameter includes the spacecraft motion speed and atomic oxygen density; Step S2, divide the surface of the spacecraft into multiple polygon mesh units, and set the initial atomic oxygen flux value or initial ultraviolet flux value of each of the polygon mesh units; Step S3, calculate the increased value of the ultraviolet flux of each polygon mesh unit at each point on the spacecraft motion orbit according to the relative motion direction, included angle of the ultraviolet irradiation with respect to the spacecraft and the ultraviolet flux influence parameter, or calculate the increased value of the atomic oxygen flux of each polygon mesh unit at each point on the spacecraft motion orbit according to the relative motion direction, included angle of the atomic oxygen particles with respect to the spacecraft and the atomic oxygen flux influence parameter, including: Step S31, determine the shielding factor of the polygon mesh unit along the reverse direction of the spacecraft motion speed according to the first calculation formula, where the first calculation formula is: the shielding factor of the polygon mesh unit along the reverse direction of the spacecraft motion speed = 1 - the number of the first intersecting rays / the number of vertices of the polygon mesh unit, where the number of the first intersecting rays is the number of intersections of the rays emitted from each vertex of the polygon of the grid unit along the reverse direction of the spacecraft motion speed; Step S32, determine the cosine value of the included angle between the normal vector of the polygon mesh unit and the reverse direction of the spacecraft motion speed; Step S33, calculate the increased value of the atomic oxygen flux of each polygon mesh unit at each point on the spacecraft motion orbit according to the atomic oxygen flux influence parameter, the cosine value of the included angle between the normal vector of the polygon mesh unit and the reverse direction of the spacecraft motion speed, and the shielding factor of the polygon mesh unit along the reverse direction of the spacecraft motion speed; Step S4, obtain the cumulative atomic oxygen flux value of each polygon mesh unit on the surface of the spacecraft according to the initial atomic oxygen flux value and the increased value of the atomic oxygen flux, or obtain the cumulative ultraviolet flux value of each polygon mesh unit on the surface of the spacecraft according to the initial ultraviolet flux value and the increased value of the ultraviolet flux.

2. The calculation method of atomic oxygen or ultraviolet flux based on ray tracing according to claim 1, characterized in that In Step S1, the ultraviolet flux influence parameter includes the ultraviolet irradiation direction, the spacecraft sun exposure factor, and the ultraviolet irradiation intensity.

3. The calculation method of atomic oxygen or ultraviolet flux based on ray tracing according to claim 1, characterized in that, In Step S33, calculating the increased value of the atomic oxygen flux of each polygon mesh unit at each point on the spacecraft motion orbit according to the atomic oxygen flux influence parameter, the cosine value of the included angle between the normal vector of the polygon mesh unit and the reverse direction of the spacecraft motion speed, and the shielding factor of the polygon mesh unit along the reverse direction of the spacecraft motion speed, includes: When the cosine value of the included angle between the normal vector of the polygon mesh unit and the reverse direction of the spacecraft motion speed is greater than 0, the increased value of the atomic oxygen flux of the polygon mesh unit at the orbit point is 0; Otherwise, the increased value of the atomic oxygen flux is the product of the shielding factor of the polygon mesh cell along the opposite direction of the spacecraft's motion speed, the absolute value of the spacecraft's motion speed, the area of the polygon of the mesh cell, the atomic oxygen density, and the absolute value of the cosine value of the angle between the normal vector of the polygon mesh cell and the opposite direction of the spacecraft's motion speed.

4. The method for calculating atomic oxygen or ultraviolet flux based on ray tracing according to claim 2, wherein In step S3, calculating the increased value of the ultraviolet flux of each polygon mesh cell at each point on the spacecraft's motion orbit according to the motion direction of the ultraviolet irradiation relative to the spacecraft, the angle, and the ultraviolet flux influence parameter includes: Step S34, determining the shielding factor of the polygon mesh cell along the opposite direction of the ultraviolet irradiation according to the second calculation formula; Step S35, determining the cosine value of the angle between the normal vector of the polygon mesh cell and the opposite direction of the ultraviolet irradiation; Step S36, calculating the increased value of the ultraviolet flux of each polygon mesh cell at each point on the spacecraft's motion orbit according to the ultraviolet flux influence parameter, the cosine value of the angle between the normal vector of the polygon mesh cell and the ultraviolet irradiation direction, and the shielding factor of the polygon mesh cell along the opposite direction of the ultraviolet irradiation.

5. The calculation method of atomic oxygen or ultraviolet flux based on ray tracing according to claim 4, characterized in that, In step S34, the second calculation formula is: the shielding factor of the polygon mesh cell along the opposite direction of the ultraviolet irradiation = 1 - the number of second intersecting rays / the number of vertices of the polygon mesh cell, where the number of second intersecting rays is the number of intersections of the rays emitted along the opposite direction of the ultraviolet irradiation by each vertex of the polygon of the mesh cell.

6. The method for calculating atomic oxygen or ultraviolet flux based on ray tracing according to claim 5, wherein In step S36, calculating the increased value of the ultraviolet flux of each polygon mesh cell at each point on the spacecraft's motion orbit according to the ultraviolet flux influence parameter, the cosine value of the angle between the normal vector of the polygon mesh cell and the ultraviolet irradiation direction, and the shielding factor of the polygon mesh cell along the opposite direction of the ultraviolet irradiation includes: When the cosine value of the angle between the normal vector of the polygon mesh cell and the ultraviolet irradiation direction is greater than 0 or the spacecraft's sun exposure factor is 0, the increased value of the ultraviolet flux of the polygon mesh cell at the orbit point is 0; Otherwise, the increased value of the ultraviolet flux is the product of the shielding factor of the polygon mesh cell along the opposite direction of the ultraviolet irradiation, the area of the polygon of the mesh cell, the ultraviolet irradiation intensity, and the absolute value of the cosine value of the angle between the normal vector of the polygon mesh cell and the ultraviolet irradiation direction.

7. The method for calculating atomic oxygen or ultraviolet flux based on ray tracing according to claim 1, wherein In step S2, the initial value of the atomic oxygen flux or the initial value of the ultraviolet flux is 0.

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