A representation method for space environment simulation data

Abstract

The present invention provides a method for characterizing space environment simulation data, which belongs to the field of aerospace technology. The method comprises: characterizing the simulation data of a spacecraft during space operation based on three-dimensional space and two-dimensional space, and drawing an instantaneous curve graph of the space environment data based on the characterization of the spacecraft's space environment in three-dimensional space and two-dimensional space based on continuous time changes. The present invention quantitatively characterizes the simulation data of the spacecraft's space operation state and its space environment from two dimensions of three-dimensional space and two-dimensional space, determines the spacecraft's spatial position and motion state through three-dimensional data, determines the spacecraft's attitude through four-dimensional data, and characterizes the spacecraft's space environment based on cloud map analysis of the spacecraft's trajectory, so that a large amount of multi-dimensional heterogeneous data can be displayed in the same scene, which is of great significance for analyzing the complex space environment of spacecraft in engineering and improving the on-orbit service life and reliability of spacecraft.

Description

Technical Field

[0001] The present invention relates to the field of aviation and aerospace technology, and in particular to a method for characterizing space environment simulation data. Background Art

[0002] The impact of the space environment on spacecraft is a fundamental focus of space environmental effects research. Key scientific questions include understanding the fundamental laws governing the interaction between the space environment and spacecraft and their engineering applications. Space environmental effects are the macroscopic and microscopic manifestations of the interaction between the space environment and spacecraft, involving various physical, chemical, and mechanical processes. The study of the space environment is the foundation and prerequisite for the study of space effects. In-depth research into the impact of the space environment on spacecraft is crucial for improving the on-orbit service life and reliability of spacecraft.

[0003] However, the space environment is extremely complex. According to different environmental types, the space environment can be divided into the upper atmosphere of the Earth, the space radiation particle environment and the space plasma environment. Among them, (1) the neutral atmosphere can produce a variety of negative effects on low-Earth orbit spacecraft. In low-Earth orbits below about 800 km, the residual atmosphere of the Earth constitutes a neutral atmosphere, which can produce aerodynamic drag on spacecraft. For large asymmetric spacecraft, the unevenness of the drag effect can produce torque, affecting the attitude of the spacecraft, which needs to be adjusted by the attitude control system. Aerodynamic drag can also cause the spacecraft's orbit to drop, and it needs to be regularly raised by the orbit control engine. Under low-Earth orbit conditions, atomic oxygen is a neutral atmospheric component that must be considered. The average kinetic energy of its impact on the front surface of the spacecraft can reach about 5eV, which can cause surface erosion of many polymer materials (such as Kapton, C / C composites) and Ag. There is an intrinsic gas environment around the spacecraft formed by the gas released by itself. Due to the effects of high vacuum and space radiation, it can cause the surface material of the spacecraft to outgas, becoming a source of contamination for optically sensitive surfaces. Neutral gas molecules generated in the backflow region of orbit control and attitude control engine plumes are also a common source of contamination. In low-Earth orbit, this neutral gas environment is often the initiator of the UV-visible-infrared diffuse luminescence phenomenon seen on spacecraft surfaces. This complex luminescence phenomenon is a recovery effect of catalytic and excitation processes on the material surface and is dependent on a variety of factors, including orbital altitude, attitude, material properties, surface temperature, time in orbit, lighting conditions, and spacecraft size. In recent years, increasing attention has been paid to the hazards of a spacecraft's own atmosphere. Firstly, it can be a source of gaseous molecular contamination, and secondly, it can easily trigger electrostatic discharge or produce a glow.

[0004] (2) The damage effects of space charged particle irradiation on spacecraft involve radiation damage and deep dielectric charging and discharging. The latter is that high-energy electrons penetrate into the interior of the spacecraft, deposit charges in the electrical insulator and eventually lead to arc discharge. Radiation damage effects can be temporary or permanent. When the energy of the charged particles is high enough, a single particle passing through may cause the state of the electronic device to change, which is called a single particle event. The resulting impact is to flip the random storage unit, increase the noise of the CCD device, and induce various error signals. In severe cases, a single particle event will cause the integration circuit to lock or burn out, resulting in permanent damage. Common space charged particle radiation damage effects are caused by the accumulation of ionizing absorbed dose, which is called the total ionizing dose effect (TID). This is a gradual accumulation process of damage, which mainly manifests as the degradation of the performance of key materials and devices such as thermal control coatings, electronic devices and optical devices. For a long time, the research on space charged particle radiation damage effects and protection has been a topic of great concern in spacecraft design, and is also an important part of the research on the interaction between the space environment and spacecraft. The electromagnetic radiation of various bands of the sun can also have an adverse effect on spacecraft. Low-frequency radio frequency interference can affect electronic systems. Infrared radiation from the sun, the Earth, and other celestial bodies can affect the thermal balance of an orbiting spacecraft. Reflection of visible light from certain surfaces or dust particles near sensors can produce weak signals or images. Solar ultraviolet radiation can directly degrade the properties of spacecraft surface materials and influence the charging and discharging processes on the surface by inducing photoelectrons. Solar ultraviolet radiation can also promote the formation of contaminant films on sensitive surfaces through photochemical bonding. X-rays and gamma rays (primarily from man-made sources) can penetrate surfaces and generate charged particles within the spacecraft's shielding, thereby affecting sensitive systems.

[0005] (3) The main impact of the plasma environment on spacecraft is that it causes current to flow into the exposed surfaces of the spacecraft, resulting in a charge accumulation effect. The electric field generated by the high-voltage power supply system exposed to the space environment will have a significant impact on the flow of this current. The accumulated charge can generate a potential difference between different electrically insulating surfaces of the spacecraft, and even cause destructive arc discharge; or, generate electromagnetic noise and ablate the surface by forming micro-arcs. This surface ablation effect will promote the formation of a gas and dust environment around the spacecraft. The low-Earth orbit plasma environment can cause high-voltage solar cell arrays (>100V) to generate arc discharges. Even under lower voltage conditions, it is necessary to avoid micro-arc discharges and the electromagnetic interference caused by solar cell arrays from the design. Generally, the operating voltage of the solar cell array should be lower than 200V (the empirical threshold of the arc starting voltage). This will significantly increase the weight of the spacecraft power distribution system. Under geosynchronous orbit conditions, the energy of the plasma is high, which will form a charging environment that is much more serious than that of the low-Earth orbit plasma, and can form a potential difference of several thousand volts between the spacecraft structure and the space plasma or between different surfaces. It has been found that the arc discharge generated can directly cause spacecraft failure. The charge accumulated on the spacecraft surface can also easily attract charged contaminant gas molecules to sensitive surfaces, causing changes in their properties. For example, this can reduce the surface's electrical conductivity or alter its charging characteristics. This suggests that under geosynchronous orbit conditions, ambient plasma and ionized gas molecules may produce synergistic effects. On the surface of solar arrays, the incoming neutral gas may also ionize and provide electrons, increasing the likelihood of arcing discharges, known as the secondary electron multiplication effect. Therefore, geosynchronous spacecraft must incorporate necessary design measures to prevent the occurrence of charging and discharging effects caused by the plasma environment.

[0006] Furthermore, during the on-orbit operation of a spacecraft, not only is the environment in which it is located in need of research, but also the characterization of its operational status data. The space environment data generated by simulation analysis in existing technologies has the following characteristics: First, the data size is enormous, with data volumes in the tens of thousands. For certain scenarios, the data volume of long-term space environment calculations can even reach hundreds of millions. Such a massive data size requires appropriate characterization methods to unravel this vast amount of data and present it in engineering applications. Second, the data types are diverse. When analyzing and characterizing the space environment in which a spacecraft resides, multiple spacecraft may exist simultaneously in the same scene, with different spacecraft operating on different orbits. At the same time, each spacecraft in a scene may be located in different spatial locations, and the space environment in which each spacecraft resides is also different. Furthermore, the space environment in which a spacecraft resides is also diverse, with numerous and complex types. A variety of simulation models are used to quantitatively characterize different types of space environments. Furthermore, the environmental data of different types of space environments vary significantly, with distinct characteristics such as unique dimensions, data values, and varying ranges.

[0007] The presentation of multi-dimensional and heterogeneous massive data in the same scene is of great significance for engineering analysis of the complex space environment of aircraft. Therefore, how to effectively and intuitively represent the multi-dimensional data encountered in the process of space environment simulation data characterization with different data types is an important technical problem that needs to be solved urgently. Summary of the Invention

[0008] The problem solved by the present invention is how to quantitatively represent the operating state of a spacecraft and the space environment simulation data of its location.

[0009] To solve the above problems, the present invention provides a method for characterizing space environment simulation data, comprising:

[0010] The simulation data of the spacecraft during its operation in space is represented in three-dimensional space, specifically including: obtaining the spacecraft's spatial position data and trajectory based on the three-dimensional Cartesian coordinate system based on continuous time changes,

[0011] Characterizing the attitude of the spacecraft in three-dimensional space,

[0012] Acquiring a cloud image along the trajectory, and characterizing the space environment of the spacecraft in three-dimensional space based on the cloud image of the trajectory;

[0013] The simulation data of the spacecraft during its operation in space are represented in two-dimensional space, specifically including: obtaining the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation based on continuous time changes,

[0014] Acquire a cloud image along the trajectory of the sub-satellite point, and characterize the space environment of the spacecraft in two-dimensional space based on the cloud image of the sub-satellite point;

[0015] Based on the continuous time change, an instantaneous curve graph of the space environment data is drawn according to the representation of the space environment of the spacecraft in three-dimensional space and two-dimensional space.

[0016] Preferably, the time is represented by Julian day, and the Julian day is calculated according to a first formula, wherein the first formula includes:

[0017] ;

[0018] Where JD represents the Julian day, INT() represents rounding, Year represents the year in the Gregorian calendar, Month represents the month, Day represents the day, Hour represents the hour, Minute represents the minute, and Second represents the second.

[0019] Preferably, the obtaining of the spatial position data and the trajectory of the spacecraft based on the three-dimensional Cartesian coordinate system includes:

[0020] Establish a three-dimensional Cartesian coordinate system, place the three-dimensional earth sphere in the three-dimensional Cartesian coordinate system, and define the origin of the three-dimensional Cartesian coordinate system at the center of mass of the three-dimensional earth sphere. Determine the three-dimensional coordinates of the spacecraft according to the X, Y, and Z coordinate axis data of the three-dimensional Cartesian coordinate system to obtain the spatial position point of the spacecraft.

[0021] Preferably, the obtaining of the spatial position data and the trajectory of the spacecraft based on the three-dimensional Cartesian coordinate system further includes:

[0022] Based on the continuous time change, the various spatial position points of the spacecraft as time passes are obtained in sequence, and the various spatial position points of the spacecraft are connected in sequence to obtain the movement trajectory of the spacecraft in space as time passes.

[0023] Preferably, characterizing the attitude of the spacecraft in three-dimensional space includes:

[0024] The orbital coordinate system is defined as O0X0Y0Z0, and the direction vector of the rotation axis e in the orbital coordinate system is ,in, Represents direction cosines, and the orbital coordinate system rotates around the rotation axis e by an angle α to obtain the satellite body coordinate system O b X b Y b Z bThe coordinate origin of the satellite body coordinate system is located at the center of mass of the spacecraft, and the X axis, Y axis, and Z axis of the satellite body coordinate system are respectively the three principal inertia axes of the spacecraft;

[0025] The attitude of the spacecraft is represented in a quaternion manner to obtain attitude quaternion data of the spacecraft. The attitude quaternion q of the spacecraft is:

[0026]

[0027] in, 、 、 are vector components, is a scalar component, and .

[0028] Preferably, the characterization of the attitude of the spacecraft in three-dimensional space also includes: solving the relative relationship between the satellite body coordinate system and the J2000 inertial coordinate system in inertial space based on the attitude quaternion data of the spacecraft, making corresponding attitude adjustments to the spacecraft and displaying it in the three-dimensional space.

[0029] Preferably, the step of obtaining a cloud map along the running trajectory includes:

[0030] Acquiring environmental data of the space environment at the space operating position of the spacecraft at different times,

[0031] According to the environmental data and a preset standard, a color corresponding to the value of the environmental data is obtained, wherein the preset standard includes a one-to-one correspondence between the color change and the value of the environmental data.

[0032] The segments at corresponding moments on the trajectory of the spacecraft are colored according to the colors to obtain a cloud map along the trajectory.

[0033] Preferably, the space environment includes an atmospheric environment, a space radiation environment and a plasma environment, wherein the atmospheric environment is described by the atmospheric mass density, the fractional density of each component and the atmospheric temperature, the space radiation environment is described by the energy level of radiation particles, and the plasma environment is described by the density and temperature of plasma particle clusters.

[0034] Preferably, the characterization of the space radiation environment includes: a real-time trajectory cloud map display along the spacecraft trajectory, a mean energy spectrum of space charged particle radiation based on the entire mission cycle, and a space instantaneous flux curve and a cumulative flux curve, wherein the flux of the radiation particles includes an integral flux and a differential flux.

[0035] Preferably, the method of obtaining the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation includes: converting the three-dimensional coordinates of the spacecraft into the WGS84 coordinate system through coordinate transformation, taking the geodetic longitude and latitude coordinates to obtain the two-dimensional coordinates of the spacecraft, and connecting them in chronological order to obtain the sub-satellite point trajectory of the spacecraft.

[0036] The beneficial effects of the present invention compared to the prior art are:

[0037] The present invention quantitatively represents the simulation data of the spacecraft's spatial operation state and its spatial environment from two dimensions of three-dimensional space and two-dimensional space based on continuous time changes, determines the spatial position motion state of the spacecraft through three-dimensional data, determines the spacecraft's attitude through four-dimensional data, and represents the spacecraft's spatial environment based on cloud map analysis of the spacecraft's operation trajectory. It realizes the representation of multi-dimensional heterogeneous data involving three-dimensional spatial coordinate representation, three-dimensional spatial attitude representation based on quaternions, three-dimensional representation of spatial environment data, two-dimensional plane trajectory representation, two-dimensional plane space environment data representation, etc., so that massive multi-dimensional heterogeneous data can be presented in the same scene, which is of great significance for analyzing the complex space environment of spacecraft in practical application engineering and improving the on-orbit service life and reliability of spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of a method for characterizing space environment simulation data according to an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the WGS-84 coordinate system in an embodiment of the present invention;

[0040] Figure 3 is a schematic diagram of an Earth-centered Earth-fixed coordinate system in an embodiment of the present invention;

[0041] Figure 4 Schematic diagram of the J2000 inertial coordinate system and the satellite body coordinate system in an embodiment of the present invention;

[0042] Figure 5 A schematic diagram of the spacecraft attitude represented by quaternion data in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of a spacecraft orbit representation in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram representing a cloud map of a spacecraft's space environment along its trajectory in an embodiment of the present invention;

[0045] Figure 8 Schematic diagram of instantaneous quantification of charged particles at various energy levels in the space radiation environment of a spacecraft according to an embodiment of the present invention;

[0046] Figure 9 Schematic diagram of instantaneous quantification of various data of the spacecraft space atmospheric environment in an embodiment of the present invention.

[0047] Reference numerals:

[0048] 1. Greenwich meridian plane; 2. Target point; 3. Equator; 4. Mean equinox at J2000 time. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0050] A method for characterizing spatial environment simulation data according to an embodiment of the present invention is as follows: Figure 1 As shown, it includes: characterizing the simulation data of the spacecraft during its operation in space based on three-dimensional space; characterizing the simulation data of the spacecraft during its operation in space based on two-dimensional space; and drawing an instantaneous curve graph of the space environment data based on the characterization of the space environment of the spacecraft in three-dimensional space and two-dimensional space based on continuous time changes.

[0051] Among them, the simulation data of the spacecraft during its operation in space is represented based on three-dimensional space, specifically including: based on continuous time changes, obtaining the spatial position data and operation trajectory of the spacecraft based on a three-dimensional Cartesian coordinate system; characterizing the posture of the spacecraft in three-dimensional space; obtaining a cloud map along the operation trajectory, and characterizing the spatial environment of the spacecraft in three-dimensional space based on the cloud map of the operation trajectory.

[0052] Among them, the simulation data of the spacecraft during its operation in space is represented based on two-dimensional space, specifically including: based on continuous time changes, obtaining the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation; obtaining a cloud map along the sub-satellite point trajectory, and representing the space environment of the spacecraft in two-dimensional space based on the cloud map of the sub-satellite point.

[0053] Since the spatial environment data obtained through computer simulation technology usually has the characteristics of huge data volume and multiple data types, the data involves spatial three-dimensional coordinate representation, spatial three-dimensional attitude representation based on quaternions, three-dimensional representation of spatial environment data, two-dimensional plane trajectory representation, two-dimensional plane spatial environment data representation, etc., the above involves the analysis and representation of multi-dimensional heterogeneous data, which is an important problem to be solved in engineering. The purpose of this invention is to solve the problem of effectively and intuitively representing multi-dimensional data encountered in the spatial environment simulation data representation process when the data types are different.

[0054] To establish a representation for multi-source, heterogeneous data about the space environment, it is first necessary to analyze and understand the multivariate data. From a multidimensional perspective, the analysis and representation of the space environment in which a spacecraft (also known as a spacecraft) resides begins with the spacecraft as the unit. Multiple spacecraft may exist simultaneously in the same scene, with different spacecraft operating on different orbits. At the same moment, each spacecraft in the scene may be located at a different spatial location, and the surrounding spatial environment is also different. Therefore, it is necessary to solve the problem for each spacecraft individually. Furthermore, the space environment in which a spacecraft resides is also multivariate, with numerous and complex environments. Numerous simulation models exist for quantitatively representing different types of space environments. Furthermore, the environmental data of different types of space environments vary significantly, with distinct dimensions, resulting in significant differences in numerical values ​​and ranges. From the perspective of data heterogeneity, the space and motion conditions of spacecraft are based on continuous time changes. The spatial position motion state of the spacecraft is determined by three-dimensional data. The description of the spacecraft attitude motion state based on quaternions is determined by four-dimensional data. The overall description of the space atmospheric environment is described by multi-dimensional data such as atmospheric mass density, fractional density of each component, and atmospheric temperature. The space radiation environment is distinguished by the different energy levels of radiation particles, and the particle flux is described by integral flux and differential flux. The plasma environment is described by the density and temperature of plasma particle clusters, etc.

[0055] From the above analysis, we can see that spacecraft space environment data has extremely strong multi-heterogeneous characteristics, so the quantitative representation of these data is extremely important and necessary. The specific analysis of multi-heterogeneous data of spacecraft space environment is as follows:

[0056] The operating status of a spacecraft changes over time, and the space environment also changes over time, so it is necessary to first analyze the time data. In the embodiment of the present invention, the Gregorian calendar year, month, day, hour, minute, and second are used as engineering applications to define UTC time. In internal simulation calculations, the time is converted into a continuous linear real number using the Julian day time, which facilitates calculation and simulation solutions. In a specific embodiment, the time is represented by the Julian day, and the method for calculating the Julian day by the Gregorian calendar is to calculate the Julian day according to the first formula, which includes:

[0057] ;

[0058] Where JD represents the Julian day, INT() represents rounding, Year represents the year in the Gregorian calendar, Month represents the month, Day represents the day, Hour represents the hour, Minute represents the minute, and Second represents the second.

[0059] In some embodiments, obtaining the spatial position data and trajectory of the spacecraft based on a three-dimensional Cartesian coordinate system includes:

[0060] Establishing a three-dimensional Cartesian coordinate system, placing the three-dimensional Earth sphere in the three-dimensional Cartesian coordinate system, defining the origin of the three-dimensional Cartesian coordinate system at the center of mass of the three-dimensional Earth sphere, and determining the three-dimensional coordinates of the spacecraft based on X, Y, and Z coordinate axis data of the three-dimensional Cartesian coordinate system to obtain the spatial position point of the spacecraft;

[0061] Based on the continuous time change, the various spatial position points of the spacecraft are obtained in sequence as the time passes, and the various spatial position points of the spacecraft are connected in sequence to obtain the trajectory of the spacecraft in space as the time passes. The characterization result is as follows: Figure 6 As shown in the figure, SAT - 1 indicates the name of the satellite.

[0062] The spacecraft's spatial operating position is described in a spatial Cartesian coordinate system. The aircraft's spatial position is determined using the coordinate system's X, Y, and Z axis data. The orbital spatial operating position is three-dimensional data. This embodiment of the present invention calculates the spacecraft's spatial position data in the J2000 geocentric inertial Cartesian coordinate system. The coordinate system used in this embodiment is described in detail below.

[0063] 1) Earth-centered Earth-fixed coordinate system: The Earth-centered Earth-fixed coordinate system is defined as follows: Figure 3 As shown, the origin of the Earth-centered, Earth-fixed coordinate system coincides with the Earth's center of mass, the Z axis points to the Earth's North Pole, the X axis points to the intersection of the equator 3 and the Greenwich meridian plane 1, and the Y axis, X axis, and Z axis form a right-handed rectangular coordinate system. The Earth-centered, Earth-fixed coordinate system can be transformed into and from the Earth-centered, Earth-fixed coordinate system.

[0064] 2) Geocentric coordinate system: The characteristic is that the latitude and longitude of the earth are used to express the orientation. In the embodiment of the present invention, the most commonly used WGS-84 coordinate system is used. The coordinate system is defined as follows: WGS-84 is a barycentric coordinate system, and the origin coincides with the center of mass of the earth. Figure 2As shown, its Z-axis points toward the Conventional Terrestrial Pole (CTP) defined by the International Time Bureau in 1984.0, the X-axis points to the intersection of the Conventional Meridian Plane and the Prime Meridian Plane with the Equator 3, and the Y-axis, along with the X- and Z-axes, forms a right-handed rectangular coordinate. The geodetic coordinates (lon, lat, alt) in the WGS-84 coordinate system are the latitude and longitude of the target in the WGS-84 coordinate system. The geodetic longitude lon is the angle between the geodetic meridian plane and the prime meridian plane of target point 2, and the geodetic latitude lat is the angle between the normal to the WGS-84 ellipsoid passing through target point 2 and the Equator 3 plane. One of the dashed lines forming the angle lat in the figure represents a line on the Equator 3 plane, and alt is the distance between target point 2 and the normal to the WGS-84 ellipsoid. The light-colored line in the figure represents the ellipsoid.

[0065] 3) J2000 Geocentric Inertial Coordinate System. The celestial reference coordinate system is defined using the celestial equator3 and the equinoxes at J2000 (January 1, 2000, 12:00). Figure 4 As shown, the origin of the J2000 coordinate system coincides with the center of mass of the Earth, the X-axis points to the mean equinox 4 at the time of J2000, the Z-axis points to the North Pole, and the Y-axis, X-axis, and Z-axis form a right-handed rectangular coordinate system, which is an inertial coordinate system.

[0066] 4) Satellite body coordinate system: The coordinate system is defined as follows, such as Figure 4 As shown, the coordinate origin is located at the satellite's center of mass, and the Xs, Ys, and Zs axes are the three principal axes of inertia of the satellite body. In the absence of attitude deviation, the three coordinate axes of the satellite body coordinate system (Xs, Ys, and Zs) coincide with the satellite orbit coordinate system. At this time, the satellite's Zs axis points toward the center of the Earth, the Xs axis coincides with the direction of satellite motion, and the Ys axis points toward the negative normal of the satellite's orbital plane, forming a right-handed rectangular coordinate system with the Xs and Zs axes. Here, α represents the orbital inclination, β represents the longitude of the ascending node, and δ represents the angular distance of periapsis.

[0067] In the prior art, Euler angles (pitch angle, yaw angle, roll angle) are usually used in the analysis and calculation of spacecraft attitude to intuitively describe the pitch, yaw, roll and other attitude changes of the spacecraft attitude. However, the Euler angle description has a singularity problem, that is, it cannot satisfy the unique correspondence between attitude and data. Therefore, the quaternion representation is introduced in this embodiment to define the satellite attitude. Therefore, the simulation process needs to process the four-dimensional data of the spacecraft attitude based on the quaternion.

[0068] In a specific embodiment, the characterization of the attitude of the spacecraft in three-dimensional space includes:

[0069] The orbital coordinate system is defined as O0X0Y0Z0, and the direction vector of the rotation axis e in the orbital coordinate system is ,in, Represents direction cosines, and the orbital coordinate system rotates around the rotation axis e by an angle α to obtain the satellite body coordinate system O b X b Y b Z b The coordinate origin of the satellite body coordinate system is located at the center of mass of the spacecraft, and the X axis, Y axis, and Z axis of the satellite body coordinate system are respectively the three principal inertia axes of the spacecraft;

[0070] The attitude of the spacecraft is represented by quaternions, and the result is as follows Figure 5 As shown, the attitude quaternion data of the spacecraft is obtained, and the attitude quaternion of the spacecraft is:

[0071]

[0072] in, 、 、 are vector components, is a scalar component, and .

[0073] In some of the embodiments, the characterization of the attitude of the spacecraft in three-dimensional space also includes: solving the relative relationship between the satellite body coordinate system and the J2000 inertial coordinate system in inertial space based on the attitude quaternion data of the spacecraft, making corresponding attitude adjustments to the spacecraft and displaying it in the three-dimensional space.

[0074] In some embodiments, the cloud map along the trajectory includes: obtaining environmental data of the space environment at the spacecraft's operating position at different times, obtaining a color corresponding to the value of the environmental data based on the environmental data and a preset standard, wherein the preset standard includes a one-to-one correspondence between color changes and the numerical values ​​of the environmental data, and coloring the segments at corresponding moments on the spacecraft's trajectory according to the colors to obtain a cloud map along the trajectory. For example, Figure 7 As shown, the space environment of the spacecraft is determined according to the spacecraft's position in space at that time. The relevant environmental values ​​are extracted, and a one-to-one correspondence standard between color changes and values ​​from small to large is established. The color corresponding to the environmental value is found, and the segment at the corresponding time is selected on the satellite trajectory for coloring. Figure 7 CRRES stands for Radiation Effect Satellite and GTO stands for Geosynchronous Transfer Orbit.

[0075] In some embodiments, obtaining the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation includes: converting the three-dimensional coordinates of the spacecraft into the WGS84 coordinate system through coordinate transformation in two-dimensional space, obtaining geodetic longitude and latitude coordinates to obtain the two-dimensional coordinates of the spacecraft, i.e., points on a two-dimensional map, and then sequentially connecting these points in chronological order to obtain the sub-satellite point trajectory of the spacecraft. The spatial environment data in two-dimensional space is represented by color segmentation using the same method as in three-dimensional space, thereby obtaining a two-dimensional spatial environment spacecraft trajectory cloud map.

[0076] In some embodiments, the space environment includes an atmospheric environment, a space radiation environment, and a plasma environment, wherein the atmospheric environment is described by atmospheric mass density, fractional density of each component, and atmospheric temperature; the space radiation environment is described by the energy level of radiation particles; and the plasma environment is described by the density and temperature of plasma particle clusters.

[0077] Specifically, the multidimensional data analysis of the space radiation environment of a spacecraft, based on the charged particle flux, is as follows. The Earth's radiation belt contains charged particles, and calculations involve numerous dimensions. The particle property dimension is divided into the positively charged proton radiation belt environment and the negatively charged electron radiation belt environment. From the particle energy level dimension, numerical values ​​can be freely selected within the range of 0.04-10 MeV for electrons and 0.1-300 MeV for protons. The calculated radiation flux is divided into two types: integral flux and differential flux, thus enabling a description of the space charged particle radiation environment.

[0078] In a specific embodiment, the characterization of the space radiation environment includes: a real-time trajectory cloud display along the spacecraft trajectory, a mean energy spectrum of space charged particle radiation based on the entire mission cycle, and a space instantaneous flux curve and a cumulative flux curve. The instantaneous quantitative characterization results of charged particles at various energy levels in the spacecraft space radiation environment are as follows: Figure 8 shown.

[0079] Specifically, the multi-dimensional heterogeneous data of the space atmospheric environment in which the spacecraft is located, which is based on the molecular number density and the atmospheric mass density and temperature, are analyzed as follows. The data dimensions calculated by the space environment atmospheric model are numerous, including the following three categories: 1. The main components of the atmosphere described by the particle number density; 2. The atmospheric density properties described by the particle material mass density; 3. The Earth's atmospheric temperature in different regions described by the atmospheric temperature.

[0080] Among them, the number density of each major component of the space atmosphere environment in type I includes: helium atom number density (per cubic centimeter), oxygen atom number density (per cubic centimeter), nitrogen molecule number density (per cubic centimeter), oxygen molecule number density (per cubic centimeter), argon atom number density (per cubic centimeter), hydrogen atom number density (per cubic centimeter), nitrogen atom number density (per cubic centimeter), atomic oxygen number density (per cubic centimeter). For the total mass density of the space atmosphere environment in type II, the atmospheric mass density (g / cm3) at different locations on the earth can be obtained. 3 ). The temperature data of the space atmosphere environment in category 3 include: exosphere temperature and the atmospheric temperature at the location, in K. The instantaneous quantitative characterization results of the above data of the spacecraft space atmosphere environment are as follows Figure 9 shown.

[0081] Specifically, the analysis of space plasma is as follows: Space plasma is an important environmental factor that affects various orbiting spacecraft. There are regions of plasma with different energies and densities in the geomagnetic layer, including the ionosphere, plasmasphere and plasma sheet. The ionosphere and plasmasphere are located in the atmosphere and the inner magnetosphere respectively, and the latter three are the outer magnetosphere plasma gathering areas. The outer magnetosphere is an important area for storing particles from the solar wind and continuously transporting them to the inner magnetosphere. It is susceptible to drastic changes due to solar and geomagnetic activities. Outside the geomagnetic layer is the thin solar wind plasma, which flows radially outward from the sun in interplanetary space. Ionosphere: The neutral atmosphere extends from the surface of the earth to an altitude of about 2500km, and the corresponding atmospheric mass density drops to about 10 -17 kg / m 3 . As the altitude continues to increase, the atmospheric density decreases continuously, and there is no strict outer boundary. The shortwave electromagnetic radiation from the sun can ionize the neutral atmosphere and produce plasma. In the altitude range of 50 to 1000 km, the area where part of the neutral atmosphere undergoes photoionization is called the ionosphere. Below 1000 km, the number density of plasma is lower than that of the neutral atmosphere. Above about 150 km, plasma rarely collides with neutral gases and hardly interacts with each other. This makes the behavior of ionospheric plasma mainly controlled by electrostatic effects. Between about 50 km and 150 km, the neutral atmosphere and the ionosphere interact in a complex way. The ionosphere is generally electrically neutral, and the electron density is equal to the total positive ion density (the sum of the densities of various positive ions). The ionosphere has a high electron density (>10 3 -10 4 cm -3 ) and low energy (equivalent temperature <3000K, average kinetic energy <0.3eV), and is often called cold, dense plasma.

[0082] Plasmasphere: Its shape is like a rotating body of dipole magnetic field lines about 5RE (RE is the radius of the earth) from the center of the earth. The plasmasphere is actually a fully ionized area in the upper atmosphere. It can be regarded as an extension of the ionosphere to the geomagnetic layer. Its main components are H + (protons) and electrons, and a small amount of He + and O + The inner boundary of the plasma layer is composed of ion components from the top of the ionosphere to the O + Change to H + The altitude of the ionosphere is defined as the time when O + The charge exchange process with H atoms, that is , leading to the formation of a plasmasphere. The inner boundary of the plasmasphere varies between 500 and 2000 km in altitude, depending on the geophysical conditions. An electric field directed toward Earth exists within the plasmasphere, which, in conjunction with the geomagnetic field, causes the plasmasphere to rotate with the Earth. Coulomb collisions cause particles in the plasmasphere to exhibit a Maxwellian velocity distribution.

[0083] Plasma sheet: Near the equatorial plane of the Earth's magnetic tail, there is a hot plasma region shaped like a flat plate with a neutral sheet in the center.

[0084] The description of the plasma environment usually defines the properties of different plasmas through the macroscopic temperature and density of the plasma cluster, and obtains the energy distribution of the plasma cluster through Maxwell function.

[0085] In some embodiments, plotting the instantaneous spatial environment data curve includes: based on the aforementioned time definition method, i.e., using the time defined by the Julian day as the basis, with the simulation start time as 0 seconds, the abscissa being the total simulation duration from the simulation start time, i.e., one abscissa being taken for each simulation step, and the ordinate being the spatial environment simulation data. The x-axis of the instantaneous spatial environment data curve is a linear coordinate representing the simulation time in seconds, and the y-axis of the instantaneous spatial environment data curve is a logarithmic coordinate representing the spatial environment data. Because the spatial environment data varies widely and exhibits orders of magnitude variations, the units are determined based on the type of spatial environment data.

[0086] The multi-heterogeneous data characterization method for space environment data of an embodiment of the present invention is mainly for solving the quantitative characterization of the spacecraft operation status and the space environment simulation data of its position. The embodiment is based on continuous time changes, and is carried out from two dimensions of three-dimensional space and two-dimensional space. The spatial position motion state of the spacecraft is determined by three-dimensional data, and the attitude of the spacecraft is determined by four-dimensional data. The spacecraft space environment is characterized based on cloud map analysis of the spacecraft operation trajectory, and the characterization of multi-heterogeneous data involving three-dimensional spatial coordinate characterization, three-dimensional spatial attitude characterization based on quaternions, three-dimensional characterization of space environment data, two-dimensional plane trajectory characterization, and two-dimensional plane space environment data characterization is realized. The representation of multi-heterogeneous data such as three-dimensional spatial coordinate characterization, three-dimensional spatial attitude characterization based on quaternions, three-dimensional characterization of space environment data, two-dimensional plane trajectory characterization, and two-dimensional plane space environment data characterization is realized, so that massive multi-heterogeneous data can be displayed in the same scene, which is of great significance for analyzing the complex space environment of spacecraft in practical application engineering and improving the on-orbit service life and reliability of spacecraft.

[0087] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for characterizing spatial environment simulation data, characterized in that: include: The simulation data of the spacecraft during its operation in space is represented in three-dimensional space, specifically including: obtaining the spacecraft's spatial position data and trajectory based on the three-dimensional Cartesian coordinate system based on continuous time changes, Characterizing the attitude of the spacecraft in three-dimensional space, Acquiring a cloud image along the trajectory, and characterizing the space environment of the spacecraft in three-dimensional space based on the cloud image of the trajectory; The simulation data of the spacecraft during its operation in space are represented in two-dimensional space, specifically including: obtaining the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation based on continuous time changes, Acquire a cloud image along the trajectory of the sub-satellite point, and characterize the space environment of the spacecraft in two-dimensional space based on the cloud image of the sub-satellite point; Drawing instantaneous curve graphs of space environment data based on continuous time changes and according to representations of the space environment of the spacecraft in three-dimensional space and two-dimensional space; The characterization of the attitude of the spacecraft in three-dimensional space includes: The orbital coordinate system is defined as O0X0Y0Z0, and the direction vector of the rotation axis e in the orbital coordinate system is ,in, Represents direction cosines, and the orbital coordinate system rotates around the rotation axis e by an angle α to obtain the satellite body coordinate system O b X b Y b Z b The coordinate origin of the satellite body coordinate system is located at the center of mass of the spacecraft, and the X axis, Y axis, and Z axis of the satellite body coordinate system are respectively the three principal inertia axes of the spacecraft; The attitude of the spacecraft is represented in a quaternion manner to obtain attitude quaternion data of the spacecraft. The attitude quaternion q of the spacecraft is: in, 、 、 are vector components, is a scalar component, and .

2. The method for characterizing spatial environment simulation data according to claim 1, characterized in that: The time is represented by Julian day, and the Julian day is calculated according to a first formula, wherein the first formula includes: ； Where JD represents the Julian day, INT represents rounding, Year represents the year in the Gregorian calendar, Month represents the month, Day represents the day, Hour represents the hour, Minute represents the minute, and Second represents the second.

3. The method for characterizing spatial environment simulation data according to claim 1, wherein: The acquisition of the spacecraft's spatial position data and trajectory based on a three-dimensional Cartesian coordinate system includes: Establish a three-dimensional Cartesian coordinate system, place the three-dimensional earth sphere in the three-dimensional Cartesian coordinate system, and define the origin of the three-dimensional Cartesian coordinate system at the center of mass of the three-dimensional earth sphere. Determine the three-dimensional coordinates of the spacecraft according to the X, Y, and Z coordinate axis data of the three-dimensional Cartesian coordinate system to obtain the spatial position point of the spacecraft.

4. The method for characterizing spatial environment simulation data according to claim 3, wherein: The obtaining of the spatial position data and the trajectory of the spacecraft based on the three-dimensional Cartesian rectangular coordinate system further includes: Based on the continuous time change, the various spatial position points of the spacecraft as time passes are obtained in sequence, and the various spatial position points of the spacecraft are connected in sequence to obtain the movement trajectory of the spacecraft in space as time passes.

5. The method for characterizing spatial environment simulation data according to claim 1, wherein: The characterization of the attitude of the spacecraft in three-dimensional space also includes: solving the relative relationship between the satellite body coordinate system and the J2000 inertial coordinate system in inertial space based on the attitude quaternion data of the spacecraft, making corresponding attitude adjustments to the spacecraft and displaying it in the three-dimensional space.

6. The method for characterizing spatial environment simulation data according to claim 1, wherein: The obtaining of a cloud image along the running trajectory includes: Acquiring environmental data of the space environment at the space operating position of the spacecraft at different times, According to the environmental data and a preset standard, a color corresponding to the value of the environmental data is obtained, wherein the preset standard includes a one-to-one correspondence between the color change and the value of the environmental data. The segments at corresponding moments on the trajectory of the spacecraft are colored according to the colors to obtain a cloud map along the trajectory.

7. The method for characterizing space environment simulation data according to claim 1, characterized in that: The space environment includes an atmospheric environment, a space radiation environment and a plasma environment, wherein the atmospheric environment is described by atmospheric mass density, fractional density of each component and atmospheric temperature, the space radiation environment is described by the energy level of radiation particles, and the plasma environment is described by the density and temperature of plasma particle clusters.

8. The method for characterizing spatial environment simulation data according to claim 7, characterized in that: The characterization of the space radiation environment includes: a real-time trajectory cloud map display along the spacecraft trajectory, a mean energy spectrum of space charged particle radiation based on the entire mission cycle, and a space instantaneous flux curve and a cumulative flux curve, wherein the flux of the radiation particles includes an integral flux and a differential flux.

9. The method for characterizing spatial environment simulation data according to claim 3, wherein: The obtaining of the two-dimensional coordinates of the spacecraft and the sub-satellite point trajectory based on coordinate transformation includes: The three-dimensional coordinates of the spacecraft are converted into the WGS84 coordinate system through coordinate transformation, and the geodetic longitude and latitude coordinates are taken to obtain the two-dimensional coordinates of the spacecraft. The sub-satellite point trajectory of the spacecraft is obtained by connecting them in sequence according to time.

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