Satellite orbit autonomous control method based on performance continuous adjustable ion electric propulsion

Abstract

The invention discloses a satellite orbit autonomous control method based on performance continuous adjustable ion electric propulsion. The method comprises the following steps: S1, constructing an optimal matching feature database of ion electric propulsion thrust performance continuous adjustable; s2, constructing an atmospheric damping-thrust incidence matrix of a typical orbit height; s3, multivariate data real-time processing is carried out based on the satellite real-time orbit parameters, the atmospheric density parameters and the satellite structure design parameters, and atmospheric damping corresponding to the orbit height is calculated in real time through a spaceborne computer; s4, a performance continuous adjustable ion electric propulsion system control module rapidly completes high-precision thrust output, and variable thrust continuous output is achieved; s5, the real-time orbit height of the satellite is compared with a preset corresponding nominal value, deviation is calculated, and orbit control height calibration is achieved; and S6, carrying out a track maintenance task based on ion electric propulsion in a self-service and continuous manner, and realizing on-track autonomous operation. According to the method, transformation and improvement of low-orbit satellite orbit control means from long-term attended operation to unmanned autonomous controllability are realized.

Description

Technical Field

[0001] The present invention relates to the field of advanced aerospace power-space electric propulsion technology, and in particular to a method for autonomous orbit control of a low-orbit satellite based on ion electric propulsion with continuously adjustable performance. Background Art

[0002] A notable feature of the on-orbit application of space electric propulsion is that the low-thrust mode works continuously for a long time. Therefore, when satellites use space electric propulsion to perform complex tasks, they are constrained by different orbital environments, and their application modes and application control strategies are diverse and very complex. In addition, the working sequence of the electric propulsion system is also relatively complex, which leads to the difficulty, low efficiency and frequent failures of ground-based manual measurement and control and application management of satellites based on electric propulsion. For some satellites with high mission frequency and complex control rate, a large amount of manpower, material and resource support is required on the ground. Therefore, it is extremely urgent to seek a method that can realize the autonomous management of satellites on orbit based on space electric propulsion, so that electric propulsion satellites have the ability to autonomously manage on orbit, which can greatly reduce the difficulty and cost of ground-based manual control. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a low-orbit satellite orbit autonomous control method based on ion electric propulsion with continuously adjustable performance, so as to solve the problems of large orbit control tasks, low efficiency, easy errors and high costs when the existing ion electric propulsion performs satellite orbit maintenance tasks.

[0004] To achieve the above object, the present invention provides a method for autonomous satellite orbit control based on ion electric propulsion with continuously adjustable performance, the method comprising the following steps: S1: Based on the ground performance test data set of the continuously adjustable ion electric propulsion system, a database of optimal matching characteristics of continuously adjustable ion electric propulsion thrust performance is constructed; S2: Based on the nominal typical orbit altitude damping database, the atmospheric damping-thrust correlation matrix of typical orbit altitude is constructed; S3: Based on the satellite's real-time orbit parameters, atmospheric density parameters and satellite structure design parameters, multivariate data is processed in real time, and the atmospheric damping corresponding to the orbital altitude is calculated in real time using the onboard computer; S4: Performance continuously adjustable ion electric propulsion system control module quickly completes high-precision thrust output and realizes variable thrust continuous output; S5: Compare the satellite's real-time orbit altitude with the preset corresponding nominal value, calculate the deviation, and realize orbit control altitude calibration; S6: Self-service and continuous orbit maintenance mission based on ion electric propulsion to achieve autonomous operation in orbit.

[0005] Further, step S1 specifically includes: S11: Based on the ground performance test data set of the continuously adjustable ion electric propulsion system, establish a multivariate parameter matching feature database with optimal thrust performance; S12: Combine the thrust performance optimal characteristic database and performance test results to form a database of specific control methods for quickly achieving different thrust performances.

[0006] Furthermore, the multivariate parameters include ion electric propulsion operating voltage, current, propellant flow rate and thrust adjustment resolution.

[0007] Furthermore, the control method may be a rapid adjustment of a single parameter, or a coupled regulation of two or more parameters.

[0008] Furthermore, in step S2, the minimum orbit-maintaining thrust values ​​required for different orbital altitudes are calculated according to the windward surface area of ​​the satellite's entire design structure and the typical orbit nominal damping rate, forming a one-to-one mapping relationship between damping and thrust.

[0009] Further, step S3 includes: S31: Use the satellite's own sensors to obtain satellite orbit parameters, orbital atmospheric density and satellite attitude parameters in real time; S32: Carry out multi-information fusion processing to obtain the damping compensation thrust value required for the current orbit.

[0010] Furthermore, the multivariate information includes orbital atmospheric density, satellite orbital parameters, satellite attitude and thrust-damping mapping association.

[0011] Further, in step S4, according to the need for real-time damping compensation, the ion electric propulsion control module performs thrust regulation and output operations based on a preset on-orbit application strategy and the control method formed in step S1.

[0012] Furthermore, in step S5, the ion electric propulsion system control module is used to perform a comparison analysis of the deviation between the satellite's real-time orbital altitude and the module's preset orbital altitude.

[0013] Furthermore, in step S6, according to the orbit control needs of the entire satellite, the ion electric propulsion system with continuously adjustable performance is used to carry out orbit maintenance operations autonomously for a long time.

[0014] Beneficial effects: The method for autonomous control of low-orbit satellite orbit based on ion electric propulsion with continuously adjustable performance proposed in the present invention is based on the continuously adjustable performance ion electric propulsion and its ground performance adjustment test that has been applied in engineering, combined with the real-time working and operating environment parameters of the on-orbit satellite, it provides a new idea for autonomous orbit maintenance of satellites, supports autonomous orbit maintenance without measurement and control conditions, and has important engineering application value; it enables electric propulsion satellites to have the ability to autonomously manage work on orbit, and can reduce the difficulty and cost of manual control on the ground. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion according to the present invention is shown; Figure 2 A flowchart of building a characteristic database of a satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion according to the present invention is shown; Figure 3 A multi-information fusion processing flow chart of a satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion according to the present invention is shown. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The following combination Figure 1-Figure 3 The specific embodiments of the present invention are described in detail. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0020] like Figure 1-Figure 3As shown, the present invention provides a low-orbit satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion, which is implemented based on the existing performance-continuously adjustable ion electric propulsion test data set and multivariate data fusion algorithm. Based on the electrical parameter data set obtained from the thrust performance-continuously adjustable ion electric propulsion ground adjustment test, this method develops a wide thrust output range performance optimal matching feature database that depends on multiple parameters such as the working voltage, current and flow rate of the ion electric propulsion system, and associates the feature database with the damping value of the nominal typical orbit height, thereby constructing a damping-thrust association matrix. Then, the satellite orbit and structural parameter data and the orbit atmospheric density detection data are used to calculate the damping required for orbit maintenance in real time through the onboard computer. Synchronously, the ion electric propulsion system control module quickly completes the adjustment and output of the high-precision thrust performance of the ion electric propulsion according to the real-time orbit damping calculation results and the damping-thrust association matrix, and autonomously completes the control of the satellite orbit height. Finally, the semi-major axis of the satellite's real-time orbit is compared with the semi-major axis of the nominal orbit height to ensure the accuracy and reliability of orbit control.

[0021] The satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion of the present invention comprises the following steps: Step S1: Based on the ground performance test data set of the ion electric propulsion system with continuously adjustable performance, a database of optimal matching characteristics of the ion electric propulsion thrust performance with continuous adjustment is constructed. Specifically, it includes: Step S11: Based on the ground performance test data set of the continuously adjustable ion electric propulsion system, which includes the performance test results of multivariate parameters traversed under different powers, different thrusts, different specific impulses, different voltages, different flow rates, different background pressures, different magnetic fields, and different neutralizer currents, key characteristic influencing parameters are proposed to establish a multivariate parameter characteristic database of ion electric propulsion with optimal performance over a wide thrust range.

[0022] The parameters used in the ion electric propulsion multivariate parameter characteristic database include: electric propulsion propellant supply flow rate, external magnetic field strength, electric propulsion anode current, and electric propulsion output thrust.

[0023] Since the on-orbit application of electric propulsion mainly focuses on thrust output performance, the optimal screening strategy mainly optimizes the accuracy of output thrust and the rapid thrust adjustment time.

[0024] like Figure 2 As shown in the figure, the process of establishing the feature database is as follows: S111. Based on the test data of long-term ground tests, multi-dimensional data processing and analysis are carried out to obtain the dependence of the thrust adjustment change of the continuously adjustable ion electric propulsion system on the propellant supply flow, electric propulsion anode current, and external magnetic field strength. The linear relationship between the thrust change and the above three parameters is obtained by using the evolution curve of the thrust change and a single parameter, combined with the least squares data fitting processing method; S112. According to the linear relationship obtained in S111, verify it through experiments. Simultaneously, during the test, measure the thrust response time and thrust adjustment accuracy when the above three parameters are adjusted, where each response time point is obtained by averaging the results of 5 sets of repeated tests. Using the analysis method in S111, obtain the linear relationship between the thrust response time, thrust adjustment accuracy and the above three parameters respectively; obtain: Thrust change ( ) and the linear relationship between the working fluid flow rate, the thrust change ( ) and the linear relationship between the anode current and the thrust change ( ) and the linear relationship between the magnetic field current; thrust response time ( ) and the linear relationship between the working fluid flow rate, thrust response time ( ) and the linear relationship between the anode current and the thrust response time ( ) and the linear relationship between the magnetic field current; thrust adjustment accuracy ( ) and the linear relationship between the working fluid flow rate and the thrust adjustment accuracy ( ) and the linear relationship between the anode current and the thrust adjustment accuracy ( ) and the linear relationship between magnetic field current; S113. Based on the linear relationship obtained from S111 and S112, a multidimensional function of the effect of working fluid flow on thrust variation, thrust response time, and thrust regulation accuracy is obtained by using a polynomial fitting analysis method; based on this method, a multidimensional function corresponding to the applied magnetic field intensity and anode current is also obtained: S114. Based on the three sets of multidimensional functions obtained in S113, a thrust adjustment function based on three adjustable parameters is constructed by using a function summation method; S115. Test and verify the regulation function obtained in S114, remove the unreasonable data points that are difficult to implement in engineering, and thus construct a database with one-to-one correspondence between propellant flow rate, external magnetic field strength, and anode current and thrust regulation: .

[0025] Step S12: Combined with the constructed thrust performance optimal characteristic database, carry out thrust performance adjustment test, and according to the performance test results, use the SWOT method to carry out weighted analysis from the four dimensions of "fastest, most stable, most efficient, and most feasible", take the result with the highest weight, and screen out a database of specific adjustment methods for quickly realizing different thrust performances (under different thrust performances, the dominant working parameters are different).

[0026] Among them, "fastest" is characterized by time indicators, "most stable" is characterized by thrust output accuracy, "most efficient" is characterized by the number of adjustment parameters, and "most feasible" is characterized by engineering feasibility. The selection criteria for indicators in the four dimensions are: shortest time, smallest thrust output deviation, least adjustment parameters, and most reliable discharge state.

[0027] SWOT is an analysis method, similar to the quadrant in mathematics, which divides the results into four categories: strengths, weaknesses, opportunities, and threats. According to the previous performance test results, the test results are summarized and classified, and the adjustment strategies with advantages and opportunities are retained; at the same time, for the data points with repeated thrust in the retained results, weighted analysis is carried out according to the four dimensions of shortest time, smallest thrust output deviation, least adjustment parameters, and most reliable discharge state, and combined with the application strategy to form a control method with different priorities.

[0028] Different control methods refer to whether to use a single adjustment method of flow rate, magnetic field, or current, or to adjust two of these parameters at the same time, or to adjust all three parameters synchronously in order to achieve high-precision thrust output in engineering applications.

[0029] The control method can be a single parameter fast adjustment, or two or more parameters coupled control. According to the previous performance test results, the test results are summarized and classified, and the control strategies with advantages and opportunities are retained; at the same time, for the data points with repeated thrust in the retained results, weighted analysis is carried out according to the four dimensions of shortest time, smallest thrust output deviation, least adjustment parameters, and most reliable discharge state, and control methods with different priorities are formed in combination with application strategies.

[0030] Step S2: Based on the nominal typical orbit height damping database, the atmospheric damping-thrust correlation matrix of the typical orbit height is constructed. Specifically, according to the area of ​​the windward surface of the satellite's entire design structure, combined with the typical orbit nominal damping rate in high or low solar activity years, the atmospheric damping suffered by different satellite flight attitudes at different orbit heights is calculated, and the average thrust compensation value required for orbit maintenance is obtained according to the damping force, and a one-to-one mapping relationship matrix between damping and average thrust is constructed; the constructed mapping relationship calculation formula is: H (track damping ∝ track height, windward equivalent area, side area) = T (thrust).

[0031] S1 establishes a database for fast and efficient thrust adjustment, while S2 uses a database of atmospheric damping at different orbital altitudes that has been used in the aerospace field. In engineering applications, it is necessary to link the atmospheric damping database with the thrust database to achieve damping balance at different orbital altitudes through thrust adjustment (that is, using thrust to offset damping).

[0032] Step S3: Perform real-time multivariate data processing based on the satellite's real-time orbit parameters, atmospheric density parameters, and satellite structural design parameters, and use the onboard computer to calculate the atmospheric damping corresponding to the orbital altitude in real time. Specifically, step S31: Use the satellite's own sensors, star catalog, and navigation and positioning system to obtain real-time parameters such as the satellite's orbit, orbital atmospheric density, and satellite attitude; step S32: Use the onboard computer and the multivariate information fusion processing algorithm based on the vector machine to carry out multivariate information fusion calculation processing such as orbital atmospheric density, orbital parameters, satellite attitude, and corresponding damping rate, and obtain the average thrust value of damping compensation required for the current orbit;

[0033] like Figure 3 As shown in Figure 2, the multivariate information fusion processing flow is as follows: S311. Based on the real-time measurement data of the satellite's own star catalog, obtain the satellite's orbital altitude, atmospheric density, damping force, and satellite attitude real-time information; S312. Based on the real-time measurement data of the satellite ground control station, the orbital height of the satellite is obtained and compared with the data measured in S311. If the error is within 1%, it is considered appropriate; S313. Combine the orbital height, damping force, satellite attitude and other data measured by S311 and S312 with the existing orbital atmospheric density database, orbital damping rate database, satellite structural number parameters (windward area), etc. to perform data fusion processing and calculate the real-time orbital damping force; S314. The real-time orbit damping force is calculated according to S313, and data fusion processing is performed on the electric propulsion application control strategy based on the orbit height measured by S311 and S312, the damping-thrust correlation matrix obtained by S12 and other information, so as to accurately obtain the real-time orbit compensation thrust and its implementation method.

[0034] Multivariate information fusion processing algorithms are a variety of mature computing and processing methods represented by vector machines.

[0035] Compensated average thrust value: Based on parameters such as the satellite revisit period, the orbital altitude to be maintained, the satellite flight attitude, solar power, and orbital damping rate, the total damping force required to maintain the satellite's orbital altitude and the operating time of the electric propulsion energy to be turned on in orbit are calculated, and the average electric propulsion thrust required to offset the total damping force is then obtained.

[0036] Step S4: The performance-continuously adjustable ion electric propulsion system control module quickly completes high-precision thrust output and realizes variable thrust continuous output. Specifically, according to the real-time damping compensation requirements obtained in step S3, the satellite service management system sends specific thrust output instructions to the ion electric propulsion system control module; the ion electric propulsion system control module responds to the instructions and autonomously starts the ion electric propulsion system working mode based on the preset on-orbit application strategy and the control method formed in step S1, and quickly performs thrust adjustment and output operations, thereby completing real-time damping compensation; Step S5: Compare the satellite's real-time orbital altitude with the preset corresponding nominal value, calculate the deviation, and implement orbital control altitude calibration. Specifically, use the ion electric propulsion system control module to conduct a comparison analysis of the deviation between the satellite's real-time orbital altitude (obtained in step S3) and the module's preset orbital altitude. If the deviation is higher than 10%, continue to perform the next orbital maintenance mission. If the deviation exceeds 10% for three consecutive times, keep the satellite status unchanged, terminate the mission, and notify the ground for manual intervention. If the deviation is lower than 10%, continue to perform the autonomous orbital maintenance mission until the deviation between the real-time satellite orbital altitude and the expected value is also lower than 10%, then stop the current orbital control mission. The real-time orbital altitude is obtained through the satellite’s own altimeter, navigation and positioning system, ground station measurement and control, etc. Nominal value: The nominal value is the orbital altitude designed for the satellite, which is a design value.

[0037] Step S6: Self-service continuous orbit maintenance mission based on ion electric propulsion to achieve autonomous operation on orbit. Specifically, according to the orbit control needs of the entire satellite and the workflow of steps S1-S5, the performance-continuously adjustable ion electric propulsion system is used to autonomously carry out orbit maintenance operations of low-orbit satellites for a long time.

[0038] This method solves the problem of low efficiency of ground-based manual measurement and control orbit maintenance caused by factors such as high frequency of low-orbit satellite orbit maintenance, long orbit maintenance time with small-thrust ion electric propulsion, and complex orbit control strategies. It realizes the transformation and improvement of low-orbit satellite orbit control means from long-term manned participation to unmanned autonomous control, and has high engineering application value and good application prospects.

[0039] Any process or method description in the flowchart of the present invention or described in other ways herein can be understood as a module, segment or part of a code including one or more executable instructions for implementing the steps of a specific logical function or process, which can be implemented in any computer-readable medium for use by an instruction execution system, device or equipment, and the computer-readable medium can be any medium containing storage, communication, propagation or transmission programs for use by execution systems, devices or equipment, including read-only memories, magnetic disks or optical disks, etc.

[0040] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, those skilled in the art can combine or combine different embodiments or examples described in this specification and the features therein without causing any contradiction.

[0041] Although the above content has shown and described the embodiments of the present invention, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace, modify and other update operations on the above embodiments within the scope of the present invention.

Claims

1. A satellite orbit autonomous control method based on performance-continuously adjustable ion electric propulsion, characterized in that: The method comprises the following steps: S1: Based on the ground performance test data set of the continuously adjustable ion electric propulsion system, a database of optimal matching characteristics of continuously adjustable ion electric propulsion thrust performance is constructed; S2: Based on the nominal typical orbit altitude damping database, the atmospheric damping-thrust correlation matrix of typical orbit altitude is constructed; S3: Based on the satellite's real-time orbit parameters, atmospheric density parameters and satellite structure design parameters, multivariate data is processed in real time, and the atmospheric damping corresponding to the orbital altitude is calculated in real time using the onboard computer; S4: Performance continuously adjustable ion electric propulsion system control module quickly completes high-precision thrust output and realizes variable thrust continuous output; S5: Compare the satellite's real-time orbit altitude with the preset corresponding nominal value, calculate the deviation, and realize orbit control altitude calibration; S6: Self-service and continuous orbit maintenance mission based on ion electric propulsion to achieve autonomous operation in orbit.

2. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized in that: Step S1 specifically includes: S11: Based on the ground performance test data set of the continuously adjustable ion electric propulsion system, establish a multivariate parameter matching feature database with optimal thrust performance; S12: Combine the thrust performance optimal characteristic database and performance test results to form a database of specific control methods for quickly achieving different thrust performances.

3. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 2 is characterized in that: The multivariate parameters include ion electric propulsion operating voltage, current, propellant flow rate and thrust adjustment resolution.

4. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 2 is characterized in that: The control method is a rapid adjustment of a single parameter, or a coupled control of two or more parameters.

5. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized by: In step S2, the minimum orbit-maintaining thrust values ​​required for different orbital altitudes are calculated according to the windward surface area of ​​the satellite's entire design structure and the typical orbit nominal damping rate, forming a one-to-one mapping relationship between damping and thrust.

6. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized by: Step S3 includes: S31: Use the satellite's own sensors to obtain satellite orbit parameters, orbital atmospheric density and satellite attitude parameters in real time; S32: Carry out multi-information fusion processing to obtain the damping compensation thrust value required for the current orbit.

7. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 6 is characterized by: The multivariate information includes orbital atmospheric density, satellite orbital parameters, satellite attitude and thrust-damping mapping association.

8. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized by: In step S4, according to the need for real-time damping compensation, the ion electric propulsion control module performs thrust adjustment and output operations based on the preset on-orbit application strategy and the control method formed in step S1.

9. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized by: In step S5, the ion electric propulsion system control module is used to perform a comparison analysis of the deviation between the satellite's real-time orbital altitude and the module's preset orbital altitude.

10. The satellite orbit autonomous control method based on performance continuously adjustable ion electric propulsion according to claim 1 is characterized by: In step S6, according to the orbit control needs of the entire satellite, the ion electric propulsion system with continuously adjustable performance is used to carry out orbit maintenance operations autonomously for a long time.

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