Atmospheric density inversion and correction method, device, equipment and storage medium

Abstract

The invention discloses an atmospheric density inversion and correction method, device and equipment and a storage medium, and relates to the technical field of atmospheric density measurement, and the atmospheric density inversion and correction method comprises the steps: obtaining two orbital elements and a space environment index; inversion is carried out on the atmospheric density according to the number of the two rows of orbits, and an empirical atmospheric density model is obtained; and correcting the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and performing motion control on the spacecraft according to the corrected empirical atmospheric density model. According to the invention, the precision of the empirical atmospheric density model can be improved, and the spacecraft motion control accuracy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of atmospheric density measurement, and in particular to an atmospheric density inversion and correction method, device, equipment and storage medium. Background Art

[0002] The thermosphere refers to the atmosphere within the altitude range of 90km to 600km from the earth's surface, where low-orbit spacecraft such as space stations and some scientific experimental satellites operate. Although the thermosphere is very thin, due to the high-speed operation of low-orbit spacecraft, the atmospheric drag perturbation caused by the thermosphere becomes the largest perturbation force except for the non-spherical gravitational perturbation of the earth, affecting the orbital life of low-orbit spacecraft.

[0003] With the continuous development of space by human beings, when performing precise orbit determination, collision avoidance warning, space operation and re-entry control of spacecraft, it is necessary to control the atmospheric density predicted by the empirical atmospheric density model. The theory of atmospheric drag perturbation is relatively mature, but due to the complex physical characteristics of the thermosphere, the accuracy of the existing empirical atmospheric density model is not high. The root mean square error, which is used as an indicator to evaluate the accuracy of the empirical atmospheric density model, is about 30%. During geomagnetic storms, the root mean square error can reach 100%, or even higher. If the root mean square error of the empirical atmospheric density model is too large, it will affect the accuracy of spacecraft motion control.

[0004] Therefore, how to improve the accuracy of the empirical atmospheric density model is a problem that needs to be solved urgently. Summary of the invention

[0005] The main purpose of this application is to provide an atmospheric density inversion and correction method, device, equipment and storage medium, aiming to solve the technical problem of how to improve the accuracy of the empirical atmospheric density model and thereby improve the accuracy of spacecraft motion control.

[0006] To achieve the above-mentioned purpose, the present application provides an atmospheric density inversion and correction method, which is applied to spacecraft motion control, and the atmospheric density inversion and correction method includes:

[0007] Get two rows of orbital elements and space environment index;

[0008] Inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model;

[0009] The empirical atmospheric density model is corrected according to the space environment index to obtain a corrected empirical atmospheric density model, and the spacecraft is motion controlled according to the corrected empirical atmospheric density model.

[0010] In one embodiment, the step of inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model comprises:

[0011] Determine the semi-major axis parameter of the spacecraft according to the two orbital elements, and establish a relationship between the semi-major axis parameter and the atmospheric density;

[0012] The horizontal motion parameters of the spacecraft are determined according to the two orbital elements, and the empirical atmospheric density model is determined according to the relationship between the horizontal motion parameters, the semi-major axis parameters and the atmospheric density.

[0013] In one embodiment, the step of determining the semi-major axis parameter of the spacecraft according to the two orbital elements and establishing a relationship between the semi-major axis parameter and the atmospheric density comprises:

[0014] Determine the wind speed factor according to the orbital inclination in the two rows of orbital elements and the velocity in the inertial system of the spacecraft;

[0015] According to the earth's gravitational constant, the preset ballistic coefficient and the wind speed factor, a relationship between the semi-major axis parameter and the atmospheric density is established.

[0016] In one embodiment, the step of determining the mean motion parameters of the spacecraft according to the two orbital elements, and determining the empirical atmospheric density model according to the relationship between the mean motion parameters and the semi-major axis parameters and the atmospheric density comprises:

[0017] Determining the horizontal motion parameters of the spacecraft according to the two rows of orbital elements;

[0018] According to the relationship between the semi-major axis parameter and the atmospheric density, and the relationship between the semi-major axis parameter, the horizontal motion parameter and the earth's gravitational constant, a relationship between the horizontal motion parameter and the atmospheric density is established;

[0019] The mean value of the horizontal motion parameter within a preset time is calculated, and the empirical atmospheric density model is determined according to the mean value and a relationship between the horizontal motion parameter and the atmospheric density.

[0020] In one embodiment, the step of correcting the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and performing motion control on the spacecraft according to the corrected empirical atmospheric density model includes:

[0021] Constructing a correction function according to the spatial environment index;

[0022] The empirical atmospheric density model is corrected according to the correction function to obtain a corrected empirical atmospheric density model, and the spacecraft is motion controlled according to the corrected empirical atmospheric density model.

[0023] In one embodiment, the step of constructing a correction function according to the spatial environment index comprises:

[0024] Constructing a corresponding correction coefficient according to the space environment index;

[0025] Optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain an optimized correction coefficient;

[0026] A correction function is obtained according to the optimized correction coefficient and the space environment index.

[0027] In one embodiment, the step of optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain the optimized correction coefficient includes:

[0028] Constructing an error equation associated with the correction coefficient according to preset density set data and the empirical atmospheric density model;

[0029] Calculation is performed according to the error equation to obtain an optimized correction coefficient.

[0030] In addition, to achieve the above-mentioned purpose, the present application also provides an atmospheric density inversion and correction device, the atmospheric density inversion and correction device comprising:

[0031] An acquisition module is used to obtain two-row orbital elements and space environment index;

[0032] An inversion module, used for inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model;

[0033] A correction module is used to correct the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and to perform motion control on the spacecraft according to the corrected empirical atmospheric density model.

[0034] In addition, to achieve the above-mentioned purpose, the present application also proposes an atmospheric density inversion and correction device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the computer program is configured to implement the steps of the atmospheric density inversion and correction method as described above.

[0035] In addition, to achieve the above-mentioned purpose, the present application also provides a storage medium, which is a computer-readable storage medium, and the computer-readable storage medium stores a program for implementing the atmospheric density inversion and correction method. The program for implementing the atmospheric density inversion and correction method is executed by a processor to implement the steps of the atmospheric density inversion and correction method as described above.

[0036] The present application provides an atmospheric density inversion and correction method. The present application firstly combines the perturbation theory with two-row orbital elements to accurately invert the empirical atmospheric density model according to the key information of the spacecraft orbit, which helps to improve the prediction accuracy of the spacecraft environment. The space environment index provides a more accurate description of the atmospheric density changes under different space environment conditions, so that the empirical atmospheric density model can be corrected, so that the prediction results of the empirical atmospheric density model are closer to the actual space environment, further improving the accuracy of the empirical atmospheric density model, and then improving the accuracy of spacecraft motion control.

[0037] In summary, the present application inverts the atmospheric density through two-row orbital elements and the space environment index, and corrects the inversion results, thereby overcoming the technical defect of the large prediction error of the empirical atmospheric density model, improving the accuracy of the empirical atmospheric density model, and thus improving the accuracy of spacecraft motion control. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 A schematic diagram of a flow chart provided for the first embodiment of the atmospheric density inversion and correction method of the present application;

[0041] Figure 2 This is a schematic diagram of the data distribution of the model density data and calibration values ​​for this application;

[0042] Figure 3 This is a schematic diagram of the module structure of the atmospheric density inversion and correction device according to an embodiment of the present application;

[0043] Figure 4 Schematic diagram of the equipment structure of the hardware operating environment involved in the atmospheric density inversion and correction method in the embodiment of the present application.

[0044] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0045] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0046] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0047] The main solution of the present application is: to obtain two rows of orbital elements and a space environment index; to invert the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model; to correct the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and to control the motion of the spacecraft according to the corrected empirical atmospheric density model.

[0048] In the development of atmospheric density models, the Jacchia series of models based on thermosphere temperature parameters, the CIRA series of models based on satellite orbit decay data, the MSIS series of models based on mass spectrometer and incoherent scattering radar observation data, and the DTM series of models based on satellite drag and atmospheric temperature have been formed. At present, the research on atmospheric density inversion is mainly based on spacecraft orbit data and satellite-borne accelerometer data. There are also extensive studies on the correction of atmospheric density models. The US Air Force Space Analysis Center has established the JB2006 model and the JB2008 model, which are considered to have a forecast accuracy better than 15%. The disadvantage is that the observation data of solar and geomagnetic activity are not real-time. The US Air Force Laboratory has carried out a high-accuracy satellite drag model (HASDM: High Accuracy of Satellite Drag Model) project based on satellite drag data using the dynamic atmospheric correction algorithm (DCA: Dynamic Calibration Atmosphere). The accuracy can reach 6% to 8% in the altitude range of 200 to 800 km, but this project is confidential and not open to the public. The European Space Agency Space Operations Center (ESOC) has carried out quasi-real-time correction of atmospheric models, which is still in its infancy. Li Xie from the Flight Control Center used temperature parameters to correct the thermosphere density, and reduced the average model error from 40% to about 3% through detection values ​​and density data sets, but lacked the use of space environment index. Miao Juan used the Shenzhou 4 detection data to establish an error library sliding correction NRLMSISE-00 model, reducing the model's three-day prediction error from 20% to about 10%, but the detection data set was limited, which was not conducive to long-term application. Chen Xuxing used the data set to establish a model correction factor, reducing the 3-day forecast error of the NRLMSISE-00 model by more than 50%, and the forecast correction time was short. Du Kai gave a short-term pattern matching algorithm for the atmospheric density model based on the actual orbit measurement data, and completed point-by-point matching through the rotation, translation and scaling of the model value, which can only meet the needs of short-term orbit prediction (3 days) during the magnetic balance period, with a short time span, failed to reveal the long-term changes in the atmosphere, and there were cases of improvement failure. Therefore, how to improve the accuracy of the atmospheric density model is a problem that needs to be solved urgently.

[0049] This application inverts the atmospheric density through two-row orbital elements and the space environment index, and corrects the inversion result, thereby overcoming the technical defect of the large prediction error of the empirical atmospheric density model, improving the accuracy of the empirical atmospheric density model, and further improving the accuracy of spacecraft motion control.

[0050] It should be noted that the execution subject of this embodiment can be an atmospheric density inversion and correction system, or a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an atmospheric density inversion and correction device capable of realizing the above functions, etc., and this embodiment does not specifically limit this. The following takes the atmospheric density inversion and correction system as an example of the execution subject to illustrate this embodiment and the following embodiments.

[0051] Based on this, this application proposes the atmospheric density inversion and correction method of the first embodiment, please refer to Figure 1 The atmospheric density inversion and correction method is applied to spacecraft motion control, and the atmospheric density inversion and correction method comprises steps S10 to S30:

[0052] Step S10, obtaining two row track elements and a space environment index;

[0053] It should be noted that the two-line orbital elements are a set of data describing the spacecraft orbit information based on radar measurement data. They are the average orbital elements after eliminating the influence of the periodic term of the non-spherical gravitational perturbation of the earth, reflecting the long-term change trend of the spacecraft orbit. Each spacecraft has two lines of orbital elements, and its data format is divided into two lines. The first line includes parameters such as the spacecraft identifier, country / organization, launch year, launch number, and number of launches; the second line includes parameters such as the spacecraft's latitude, ascending node longitude, orbital inclination, perigee time, perigee argument, mean perigee angular velocity, and orbital period.

[0054] Space environment index is a parameter that describes the operating environment conditions of spacecraft and the impact on atmospheric density, which may include solar activity level, Earth's magnetic field strength or cosmic ray flux, etc. It can be obtained through various satellite observations, ground observations or numerical simulations.

[0055] Step S20, inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model;

[0056] It should be noted that the two orbital elements can be combined with the relevant theories or models of spacecraft motion control to invert the empirical atmospheric density model related to the spacecraft motion control process. The inversion process of this model can take into account the factors affecting the spacecraft in the atmosphere such as resistance and gravity, so that the spacecraft can be accurately controlled later based on the obtained empirical atmospheric density model.

[0057] Step S30, correcting the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and performing motion control on the spacecraft according to the corrected empirical atmospheric density model.

[0058] It should be noted that in the process of correcting the empirical atmospheric density model according to the space environment index, the atmospheric density value data with higher accuracy than the empirical atmospheric density model can be combined, and these data can be compared with the output of the empirical atmospheric density model, and the output of the empirical atmospheric density model can be corrected by adjusting the empirical atmospheric density model parameters or using correction factors; or a correction model can be established by using a machine learning algorithm such as a neural network or regression model for correction. After the correction is completed, the empirical atmospheric density model can more accurately reflect the current space environment conditions. The corrected empirical atmospheric density model can be applied to orbit prediction, attitude control or propulsion system design. The corrected model can be used to more accurately predict changes in atmospheric density, thereby optimizing the motion control strategy of the spacecraft.

[0059] This application provides an atmospheric density inversion and correction method. This application first uses two lines of orbital elements combined with perturbation theory to accurately invert the empirical atmospheric density model based on the key information of the spacecraft orbit, which helps to improve the accuracy of the prediction of the environment in which the spacecraft is located. The space environment index provides a more accurate description of the atmospheric density changes under different space environment conditions, so that the empirical atmospheric density model can be corrected, so that the prediction results of the empirical atmospheric density model are closer to the actual space environment, further improving the accuracy of the empirical atmospheric density model, and then improving the accuracy of spacecraft motion control.

[0060] In summary, the present application inverts the atmospheric density through two-row orbital elements and the space environment index, and corrects the inversion results, thereby overcoming the technical defect of the large prediction error of the empirical atmospheric density model, improving the accuracy of the empirical atmospheric density model, and thus improving the accuracy of spacecraft motion control.

[0061] In a feasible implementation, step S20 may include steps S201 to S202:

[0062] Step S201, determining the semi-major axis parameter of the spacecraft according to the two orbital elements, and establishing a relationship between the semi-major axis parameter and the atmospheric density;

[0063] Step S202, determining the horizontal motion parameters of the spacecraft according to the two orbital elements, and determining an empirical atmospheric density model according to a relationship between the horizontal motion parameters, the semi-major axis parameters and the atmospheric density.

[0064] It should be noted that the semi-major axis parameters of the spacecraft can be derived based on the perturbation theory and two rows of orbital elements. The information of the orbital inclination, perigee distance and apogee distance of the spacecraft can be obtained based on the two rows of orbital elements. The radius of the spacecraft orbital ellipse can be calculated based on the perigee distance and apogee distance of the orbit. The semi-major axis of the orbital ellipse is the average value of the radius of the orbital ellipse. According to the perturbation theory, considering the influence of perturbation effects such as the gravitational field on the orbit, the orbital semi-major axis is corrected to make it more consistent with the actual orbit. The corrected semi-major axis is the semi-major axis parameter of the spacecraft. According to the relationship between the semi-major axis parameter and the atmospheric density in the perturbation theory, the relationship between the semi-major axis parameter and the atmospheric density is established to describe the atmospheric influence on the spacecraft at different orbital positions. The horizontal motion parameters describe the motion state of objects on the orbit, including the orbital inclination, the position of the perigee and the apogee, etc. The horizontal motion parameters of the spacecraft can be determined by the two rows of orbital elements. By using the horizontal motion parameters and semi-major axis parameters as well as the previously established relationship between the semi-major axis parameters and the atmospheric density, the relationship between the atmospheric density conditions and the spacecraft motion state is determined, making it easier to perform attitude control, position control or motion control on the spacecraft based on the atmospheric density.

[0065] The method of this embodiment is used to invert the atmospheric density values ​​of the GRACE-A satellite along the track in 2003 and 2007, and the density calculation result ρ c , ρ d represents the measured density, The inversion value obtained by inverting the atmospheric density using the two-row orbital elements of the GRACE-A satellite is shown in the following density relative error statistics table, where RMS represents the root mean square error of the two, MRE represents the mean relative error, and Mean of ratio represents the mean of the ratio. It can be seen that the error of the empirical atmospheric density model value relative to the measured density in this embodiment is close to the error of the inversion value relative to the measured density, indicating that the empirical atmospheric density model inverted according to the method of this embodiment has a certain accuracy.

[0066] Density relative error statistics table

[0067]

[0068] In this embodiment, by using known orbital parameters, such as semi-major axis and peaceful motion parameters, and an atmospheric density model established by historical data, the atmospheric density can be inverted and estimated according to the orbital position change of the spacecraft. By establishing a relationship between the semi-major axis parameter and the atmospheric density, the influence of different orbital altitudes and orbital shapes on the atmospheric density can be considered, and the empirical atmospheric density model can be determined by the motion state of the spacecraft to achieve the association between the atmospheric density state and the motion state of the spacecraft, so as to facilitate the attitude control, position control or motion control of the spacecraft according to the atmospheric density.

[0069] In a feasible implementation, step S201 may include steps S2011 to S2012:

[0070] Step S2011, determining a wind speed factor according to the orbital inclination in the two rows of orbital elements and the speed in the inertial system of the spacecraft;

[0071] Step S2012, establishing a relationship between the semi-major axis parameter and the atmospheric density according to the earth's gravitational constant, the preset ballistic coefficient and the wind speed factor.

[0072] It should be noted that F is the wind speed factor, and the calculation formula is as follows:

[0073]

[0074] Among them, r is the distance from the center of the earth, ω e is the angular velocity of the Earth's rotation, i is the orbital inclination in the two rows of orbital elements, and v is the velocity of the spacecraft in the inertial system in the two rows of orbital elements.

[0075] The change of the semi-major axis is mainly caused by atmospheric drag and solar radiation pressure (SRP). According to perturbation theory, the relationship between the semi-major axis parameter and the atmospheric density can be written as:

[0076]

[0077] Among them, a M is the semi-major axis parameter, μ is the earth's gravitational constant, B is the preset ballistic coefficient, ρ is the atmospheric density, F is the wind speed factor, and v is the spacecraft inertial velocity in the two rows of orbital elements.

[0078] In the atmospheric drag perturbation acceleration, the ballistic coefficient B and the atmospheric density ρ are coupled together. In order to improve the inversion accuracy, the estimated ballistic coefficient can be derived based on the fluid mechanics theory as the preset ballistic coefficient, or it can be set according to the actual application.

[0079] In this implementation, the effects of multiple factors such as orbital inclination and spacecraft speed on the spacecraft orbit and operation are comprehensively considered, making the description of the relationship between the semi-major axis parameters and the atmospheric density more comprehensive and accurate, which helps to more accurately predict the operation of the spacecraft under different atmospheric densities, improve the prediction accuracy, and improve the accuracy of spacecraft motion control.

[0080] In a feasible implementation, step S202 may include steps S2021 to S2023:

[0081] Step S2021, determining the horizontal motion parameters of the spacecraft according to the two orbital elements;

[0082] Step S2022, establishing a relationship between the semi-major axis parameter and the atmospheric density according to the relationship between the semi-major axis parameter and the atmospheric density, and the relationship between the semi-major axis parameter, the horizontal motion parameter and the earth's gravitational constant;

[0083] Step S2023, calculating the mean of the horizontal motion parameter within a preset time, and determining an empirical atmospheric density model according to the mean and a relationship between the horizontal motion parameter and atmospheric density.

[0084] It should be noted that the relationship between the semi-major axis parameter, the horizontal motion parameter and the Earth's gravitational constant is:

[0085]

[0086] Among them, a M is the semi-major axis parameter, n M is the horizontal motion parameter, μ is the gravitational constant of the earth.

[0087] When the influence of solar radiation pressure SRP on spacecraft below 1000km is ignored, it can be obtained that:

[0088]

[0089] Further we can get:

[0090]

[0091] in, Indicates t k Time and t i Moment level movement M The mean is(t i ,t k ) is the weighted average of the atmospheric density ρ along the track during the period, with the weight Fv 3 .

[0092] In the atmospheric drag perturbation acceleration, the ballistic coefficient B and the atmospheric density ρ are coupled together. In order to improve the inversion accuracy, it is necessary to accurately determine the average ballistic coefficient The average ballistic coefficient can be determined by measuring or calculating the average value of the various ballistic coefficients of the spacecraft under specific conditions. Averaging can reduce the impact of changes in aerodynamic performance of the spacecraft under different operating conditions on the overall operating state, thereby simplifying the analysis and design process. Solve the above equation by segmented accumulation (assuming the step size is Δt) The inversion equation of the empirical atmospheric density model is obtained as follows:

[0093]

[0094] In this implementation, by calculating the mean of the horizontal motion parameters within a preset time, the noise and fluctuation in the data can be reduced, and more stable horizontal motion parameters can be obtained. According to the orbital motion parameters of the spacecraft and the empirical atmospheric density model of the atmospheric density, the operation of the spacecraft under different orbital positions and atmospheric densities can be considered, thereby obtaining a more accurate empirical atmospheric density model, providing an accurate reference for the motion control of the spacecraft.

[0095] In a feasible implementation, step S30 may include steps S301 to S302:

[0096] Step S301, constructing a correction function according to the spatial environment index;

[0097] Step S302, correcting the empirical atmospheric density model according to the correction function to obtain a corrected empirical atmospheric density model, and performing motion control on the spacecraft according to the corrected empirical atmospheric density model.

[0098] It should be noted that the existing empirical atmospheric model correction methods include scale bias correction and model parameter correction. Model parameter correction generally corrects the thermosphere temperature parameters. For example, the DCA algorithm (Distributed Consistency Algorithm) uses 13 spherical harmonic coefficients to correct the inflection point temperature T of the Jacchia71 model. x and the exosphere temperature T ∞ To calibrate the temperature distribution of the thermosphere and ultimately change the density distribution. There is also a method of correcting the scale deviation of the CIRA-72 model based on the model correction method for altitude, subsatellite latitude, and local solar time, but the significant disadvantage of this correction method is that the calculation is complicated and is not conducive to the rapid prediction and calibration of atmospheric density.

[0099] The space environment index is a parameter that describes the operating environment conditions of the spacecraft and affects the atmospheric density. It may include the level of solar activity, the strength of the Earth's magnetic field, cosmic ray flux, etc. A correction function is established to describe the relationship between the space environment index and the atmospheric density model. The correction function can be linear, nonlinear, or a set of equations. The obtained space environment index is used as the input of the correction function, and the empirical atmospheric density model is corrected using the correction function. The correction function adjusts the parameters or output of the empirical atmospheric density model according to the input space environment index. After correction, the corrected empirical atmospheric density model is obtained, which can determine the impact of specific space environment conditions on the atmospheric density, and thus more accurately predict the orbital changes of spacecraft under different environments in practical applications.

[0100] For example, when the space environment index includes F10.7 、F 10.7a When and Ap, construct the correction function f(F 10.7 ,F 10.7a ,Ap). Among them, F 10.7 Can represent the periodic changes in atmospheric density, F 10.7a It describes the long-term trend of atmospheric density, and Ap can represent the short-term high-frequency disturbance of geomagnetic activity on atmospheric density. At this time, the corrected empirical atmospheric density model can be defined as:

[0101] ρ corr (t) = f(F 10.7 ,F 10.7a ,Ap)·ρ uncorr (t)

[0102] Among them, ρ corr (t) represents the corrected empirical atmospheric density model, ρ uncorr (t) represents the empirical atmospheric density model to be corrected.

[0103] As a demonstration, the model density data of the GRACE-A satellite in 2003, 2004, 2007 and 2008 are selected for correction demonstration, and the results are as follows: Figure 2 As shown in the figure, the light-colored dots represent the model density data before correction, and the dark-colored dots represent the calibration values ​​after correction. It can be seen that the average error value of the model has been significantly reduced, which means that the accuracy of the model has been improved after correction, and the process of calculating complex spherical harmonic function coefficients and their partial derivatives has been avoided. Figure 2 In the figure, the ordinate MRE represents the mean relative error, the abscissa days represents the number of days, and calibration represents the calibration value. Figure 2 In (a), Model density and calibration values ​​in 2003 represent the model density data and calibration values ​​in 2003. Figure 2 In (b), Model density and calibration values ​​in 2004 represent the model density data and calibration values ​​in 2004. Figure 2 In (c), Model density and calibration values ​​in 2007 represent the model density data and calibration values ​​in 2007. Figure 2 In (d), Model density and calibration values ​​in 2008 represents the model density data and calibration values ​​in 2008.

[0104] In addition, the coefficients of the correction function of the previous year can be used to calibrate the forecast of the empirical density model for the next year, which can improve the forecast accuracy of the empirical atmospheric model.

[0105] In this implementation, by considering specific space environment factors, the correction function can make the empirical atmospheric density model more accurately reflect the actual situation. The corrected model can more accurately predict the atmospheric density, provide a reference for the orbit design and control of the spacecraft, and improve the accuracy of the spacecraft motion control.

[0106] In a feasible implementation, step S301 may include steps S3011 to S3013:

[0107] Step S3011, constructing a corresponding correction coefficient according to the space environment index;

[0108] Step S3012, optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain an optimized correction coefficient;

[0109] Step S3013, obtaining a correction function according to the optimized correction coefficient and the space environment index.

[0110] It should be noted that the space environment index includes F 10.7 、F 10.7a and Ap, F 10.7 Can represent the periodic changes in atmospheric density, F 10.7a It describes the long-term trend of atmospheric density. Ap can represent the short-term high-frequency disturbance of geomagnetic activity on atmospheric density. At the same time, the influence of three space environment indices on atmospheric density is considered, and the correction coefficients corresponding to the three space environment indices are constructed. The correction function is shown in the following formula:

[0111] f=k1+k2F 10.7 +k3F 10.7a +k4Ap

[0112] Among them, k1 is the constant term of the correction function, k2, k3 and k4 correspond to F 10.7 、F 10.7a and the correction factor of Ap.

[0113] The preset density set data generally selects a set of atmospheric density values ​​with higher accuracy than the above-mentioned empirical atmospheric density model. For example, the atmospheric density values ​​along the track obtained by inverting two rows of orbital elements of multiple satellites running on the same orbit can be selected. According to the preset density set data and the empirical atmospheric density model, the least squares method, gradient descent method, Newton method or other optimization algorithms or parameter fitting methods can be used to optimize the correction coefficients, and the optimized values ​​of k1, k2, k3 and k4 are obtained as correction coefficients. Combined with the above-mentioned correction function formula, the correction function is obtained.

[0114] In this embodiment, by constructing a correction coefficient based on the space environment index and integrating the optimized correction coefficient into the correction function, the correction function can accurately map the space environment index to the corresponding correction value, which helps to more accurately adjust the empirical atmospheric density model and make the correction function take into account the influence of different space environment conditions, thereby improving the accuracy and applicability of the empirical atmospheric density model, and further helping to improve the accuracy of spacecraft motion control.

[0115] In a feasible implementation, step S302 may include steps S3021 to S3022:

[0116] Step S3021, constructing an error equation associated with the correction coefficient according to the preset density set data and the empirical atmospheric density model;

[0117] Step S3022: Calculate according to the error equation to obtain an optimized correction coefficient.

[0118] It should be noted that, based on the preset density set data and the empirical atmospheric density model, the error equation is constructed as follows:

[0119] ∑(ρ set (t)-ρ corr (t)) 2

[0120] Among them, ρ set Represents the preset density set data, ρ corr (t) represents the density value of the corrected empirical atmospheric density model. When the residual square sum is minimized, the target parameter H of the error equation is obtained.

[0121] According to the target parameter H, the corrected empirical atmospheric density model density value ρ corr The matrix form of (t) can be expressed as:

[0122] ρ corr =HK

[0123]

[0124] ρ uncorrrepresents the empirical atmospheric density model density value to be corrected, F 10.7 、F 10.7a and Ap is the spatial environment index, then K can be obtained as:

[0125] K=(H T H) -1 H T ρ set

[0126] H is the n×4 partial derivative matrix, n is ρ set The data length is (n≥4), 1≤i≤n. By calculating the matrix parameters when the partial derivative of the target parameter H is zero, the optimal K parameter estimate can be obtained.

[0127] Among them, the relationship between K and the correction coefficient is:

[0128] K=[k1 k2 k3 k4] T

[0129] According to the specific value of K, the optimized correction coefficients k1, k2, k3 and k4 can be obtained respectively.

[0130] In this embodiment, by constructing an error equation based on preset density set data and optimizing model parameters through the least squares method, the correction process of calculating complex spherical harmonic coefficients and their partial derivatives is avoided, the amount of correction calculations can be reduced, and the correction efficiency can be improved. The corrected empirical atmospheric density model can better fit the actual data and adapt to different environmental conditions and input parameters, thereby improving the generalization ability, applicability and accuracy of the empirical atmospheric density model, which in turn helps to improve the accuracy of spacecraft motion control.

[0131] The present application also provides an atmospheric density inversion and correction device, please refer to Figure 3 , the atmospheric density inversion and correction device comprises:

[0132] An acquisition module 10 is used to obtain two orbital elements and a space environment index;

[0133] An inversion module 20 is used to invert the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model;

[0134] The correction module 30 is used to correct the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and to perform motion control on the spacecraft according to the corrected empirical atmospheric density model.

[0135] Optionally, the inversion module 20 further includes:

[0136] Determine the semi-major axis parameter of the spacecraft according to the two orbital elements, and establish a relationship between the semi-major axis parameter and the atmospheric density;

[0137] The horizontal motion parameters of the spacecraft are determined according to the two orbital elements, and the empirical atmospheric density model is determined according to the relationship between the horizontal motion parameters, the semi-major axis parameters and the atmospheric density.

[0138] Optionally, the inversion module 20 further includes:

[0139] Determine the wind speed factor according to the orbital inclination in the two rows of orbital elements and the velocity in the inertial system of the spacecraft;

[0140] According to the earth's gravitational constant, the preset ballistic coefficient and the wind speed factor, a relationship between the semi-major axis parameter and the atmospheric density is established.

[0141] Optionally, the inversion module 20 further includes:

[0142] Determining the horizontal motion parameters of the spacecraft according to the two rows of orbital elements;

[0143] According to the relationship between the semi-major axis parameter and the atmospheric density, and the relationship between the semi-major axis parameter, the horizontal motion parameter and the earth's gravitational constant, a relationship between the horizontal motion parameter and the atmospheric density is established;

[0144] The mean value of the horizontal motion parameter within a preset time is calculated, and the empirical atmospheric density model is determined according to the mean value and a relationship between the horizontal motion parameter and the atmospheric density.

[0145] Optionally, the correction module 30 further includes:

[0146] Constructing a correction function according to the spatial environment index;

[0147] The empirical atmospheric density model is corrected according to the correction function to obtain a corrected empirical atmospheric density model, and the spacecraft is motion controlled according to the corrected empirical atmospheric density model.

[0148] Optionally, the correction module 30 further includes:

[0149] Constructing a corresponding correction coefficient according to the space environment index;

[0150] Optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain an optimized correction coefficient;

[0151] A correction function is obtained according to the optimized correction coefficient and the space environment index.

[0152] Optionally, the correction module 30 further includes:

[0153] Constructing an error equation associated with the correction coefficient according to preset density set data and the empirical atmospheric density model;

[0154] Calculation is performed according to the error equation to obtain an optimized correction coefficient.

[0155] The atmospheric density inversion and correction device provided in the embodiment of the present application adopts the atmospheric density inversion and correction method in the above embodiment, which can solve the technical problem of how to improve the comprehensiveness and accuracy of the diagnostic report. Compared with the prior art, the beneficial effects of the atmospheric density inversion and correction device provided in the embodiment of the present application are the same as the beneficial effects of the atmospheric density inversion and correction method provided in the above embodiment, and the other technical features in the atmospheric density inversion and correction device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0156] The present application provides an atmospheric density inversion and correction device, which includes: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the atmospheric density inversion and correction method in the above-mentioned embodiment one.

[0157] Reference below Figure 4 , which shows a schematic diagram of the structure of an atmospheric density inversion and correction device suitable for implementing the embodiment of the present application. The atmospheric density inversion and correction device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 4 The atmospheric density inversion and correction device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0158] like Figure 4As shown, the atmospheric density inversion and correction device may include a processing device 1001 (such as a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. Various programs and data required for the operation of the atmospheric density inversion and correction device are also stored in the RAM 1004. The processing device 1001, the ROM 1002, and the RAM 1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the atmospheric density inversion and correction device to communicate wirelessly or wired with other devices to exchange data. Although the atmospheric density inversion and correction device with various systems is shown in the figure, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have instead.

[0159] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0160] The atmospheric density inversion and correction device provided by the present application adopts the atmospheric density inversion and correction method in the above embodiment, which can solve the technical problem of how to improve the accuracy of the empirical atmospheric density model and thus improve the accuracy of spacecraft motion control. Compared with the prior art, the beneficial effects of the atmospheric density inversion and correction device provided by the present application are the same as the beneficial effects of the atmospheric density inversion and correction method provided by the above embodiment, and the other technical features of the atmospheric density inversion and correction device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0161] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0162] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0163] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the atmospheric density inversion and correction method in the above-mentioned embodiment.

[0164] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0165] The computer-readable storage medium may be included in the atmospheric density inversion and correction device; or may exist independently without being assembled into the atmospheric density inversion and correction device.

[0166] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the atmospheric density inversion and correction device, the atmospheric density inversion and correction device: obtains two rows of orbital elements and a space environment index; inverts the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model; corrects the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and performs motion control on the spacecraft according to the corrected empirical atmospheric density model.

[0167] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0168] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0169] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0170] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned atmospheric density inversion and correction method, and can solve the technical problems of atmospheric density inversion and correction. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the atmospheric density inversion and correction method provided in the above-mentioned embodiment, and will not be repeated here.

[0171] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent processing scope of the present application.

Claims

1. A method for inversion and correction of atmospheric density, characterized in that: The atmospheric density inversion and correction method is applied to spacecraft motion control, and the atmospheric density inversion and correction method comprises: Get two rows of orbital elements and space environment index; Inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model; The empirical atmospheric density model is corrected according to the space environment index to obtain a corrected empirical atmospheric density model, and the spacecraft is motion controlled according to the corrected empirical atmospheric density model.

2. The method according to claim 1, characterized in that The step of inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model comprises: Determine the semi-major axis parameter of the spacecraft according to the two orbital elements, and establish a relationship between the semi-major axis parameter and the atmospheric density; The horizontal motion parameters of the spacecraft are determined according to the two orbital elements, and the empirical atmospheric density model is determined according to the relationship between the horizontal motion parameters, the semi-major axis parameters and the atmospheric density.

3. The method according to claim 2, characterized in that The step of determining the semi-major axis parameter of the spacecraft according to the two orbital elements and establishing a relationship between the semi-major axis parameter and the atmospheric density comprises: Determine the wind speed factor according to the orbital inclination in the two rows of orbital elements and the velocity in the inertial system of the spacecraft; According to the earth's gravitational constant, the preset ballistic coefficient and the wind speed factor, a relationship between the semi-major axis parameter and the atmospheric density is established.

4. The method according to claim 3, characterized in that The step of determining the horizontal motion parameters of the spacecraft according to the two orbital elements, and determining the empirical atmospheric density model according to the relationship between the horizontal motion parameters, the semi-major axis parameters and the atmospheric density, comprises: Determining the horizontal motion parameters of the spacecraft according to the two rows of orbital elements; According to the relationship between the semi-major axis parameter and the atmospheric density, and the relationship between the semi-major axis parameter, the horizontal motion parameter and the earth's gravitational constant, a relationship between the horizontal motion parameter and the atmospheric density is established; The mean value of the horizontal motion parameter within a preset time is calculated, and the empirical atmospheric density model is determined according to the mean value and a relationship between the horizontal motion parameter and the atmospheric density.

5. The method according to claim 1, characterized in that The step of correcting the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and performing motion control on the spacecraft according to the corrected empirical atmospheric density model comprises: Constructing a correction function according to the spatial environment index; The empirical atmospheric density model is corrected according to the correction function to obtain a corrected empirical atmospheric density model, and the spacecraft is motion controlled according to the corrected empirical atmospheric density model.

6. The method according to claim 5, characterized in that The step of constructing a correction function according to the space environment index comprises: Constructing a corresponding correction coefficient according to the space environment index; Optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain an optimized correction coefficient; A correction function is obtained according to the optimized correction coefficient and the space environment index.

7. The method according to claim 6, characterized in that The step of optimizing the correction coefficient according to the preset density set data and the empirical atmospheric density model to obtain the optimized correction coefficient comprises: Constructing an error equation associated with the correction coefficient according to preset density set data and the empirical atmospheric density model; Calculation is performed according to the error equation to obtain an optimized correction coefficient.

8. An atmospheric density inversion and correction device, characterized in that: The atmospheric density inversion and correction device comprises: An acquisition module is used to obtain two-row orbital elements and space environment index; An inversion module, used for inverting the atmospheric density according to the two rows of orbital elements to obtain an empirical atmospheric density model; A correction module is used to correct the empirical atmospheric density model according to the space environment index to obtain a corrected empirical atmospheric density model, and to perform motion control on the spacecraft according to the corrected empirical atmospheric density model.

9. An atmospheric density inversion and correction device, characterized in that: The atmospheric density inversion and correction device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the atmospheric density inversion and correction method as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the atmospheric density inversion and correction method according to any one of claims 1 to 7 are implemented.

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